Sample records for acceptable toxicant concentrations

  1. Freeform solar concentrator with a highly asymmetric acceptance cone

    NASA Astrophysics Data System (ADS)

    Wheelwright, Brian; Angel, J. Roger P.; Coughenour, Blake; Hammer, Kimberly

    2014-10-01

    A solar concentrator with a highly asymmetric acceptance cone is investigated. Concentrating photovoltaic systems require dual-axis sun tracking to maintain nominal concentration throughout the day. In addition to collecting direct rays from the solar disk, which subtends ~0.53 degrees, concentrating optics must allow for in-field tracking errors due to mechanical misalignment of the module, wind loading, and control loop biases. The angular range over which the concentrator maintains <90% of on-axis throughput is defined as the optical acceptance angle. Concentrators with substantial rotational symmetry likewise exhibit rotationally symmetric acceptance angles. In the field, this is sometimes a poor match with azimuth-elevation trackers, which have inherently asymmetric tracking performance. Pedestal-mounted trackers with low torsional stiffness about the vertical axis have better elevation tracking than azimuthal tracking. Conversely, trackers which rotate on large-footprint circular tracks are often limited by elevation tracking performance. We show that a line-focus concentrator, composed of a parabolic trough primary reflector and freeform refractive secondary, can be tailored to have a highly asymmetric acceptance angle. The design is suitable for a tracker with excellent tracking accuracy in the elevation direction, and poor accuracy in the azimuthal direction. In the 1000X design given, when trough optical errors (2mrad rms slope deviation) are accounted for, the azimuthal acceptance angle is +/- 1.65°, while the elevation acceptance angle is only +/-0.29°. This acceptance angle does not include the angular width of the sun, which consumes nearly all of the elevation tolerance at this concentration level. By decreasing the average concentration, the elevation acceptance angle can be increased. This is well-suited for a pedestal alt-azimuth tracker with a low cost slew bearing (without anti-backlash features).

  2. Development of an acceptable factor to estimate chronic end points from acute toxicity data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Venman, B.C.; Flaga, C.

    1985-12-01

    Acceptable daily intake (ADI) values are routinely developed for threshold toxicants from NOAELs determined from human or animal chronic or subchronic data. These NOAELs are then divided by appropriate uncertainty factors ranging from 10 to 1000 depending on the quality of the data. However, for the vast majority of chemicals used industrially, adequate toxicity data needed to use this process are not available. Thus, a procedure to estimate a chronic toxicity endpoint from acute toxicity data, such as an oral rat LD50, becomes necessary. An acute-to-chronic application factor of 0.0001 was developed, which when multiplied by an oral LD50 formore » an individual chemical, yields a surrogate chronic NOAEL. This figure can then be used to estimate an acceptable daily exposure for humans. The process used to estimate this application factor is detailed.« less

  3. Group Waterpipe Tobacco Smoking Increases Smoke Toxicant Concentration

    PubMed Central

    Ramôa, Carolina P.; Shihadeh, Alan; Salman, Rola

    2016-01-01

    Abstract Introduction: Waterpipe tobacco smoking is a global health concern. Laboratory research has focused on individual waterpipe users while group use is common. This study examined user toxicant exposure and smoke toxicant yield associated with individual and group waterpipe smoking. Methods: Twenty-two pairs of waterpipe smokers used a waterpipe individually and as a dyad. Before and after smoking, blood was sampled and expired carbon monoxide (CO) measured; puff topography was recorded throughout. One participant from each pair was selected randomly and their plasma nicotine and expired air CO concentrations were compared when smoking alone to when smoking as part of a dyad. Recorded puff topography was used to machine-produce smoke that was analyzed for toxicant content. Results: There was no difference in mean plasma nicotine concentration when an individual smoked as part of a dyad (mean = 14.9ng/ml; standard error of the mean [ SEM ] = 3.0) compared to when smoking alone (mean = 10.0ng/ml; SEM = 1.5). An individual smoking as part of as a dyad had, on average, lower CO (mean = 15.8 ppm; SEM = 2.0) compared to when smoking alone (mean= 21.3 ppm; SEM = 2.7). When two participants smoked as a dyad they took, on average, more puffs (mean = 109.8; SEM = 7.6) than a singleton smoker (mean = 77.7; SEM = 8.1) and a shorter interpuff interval (IPI; dyad mean = 23.8 seconds; SEM = 1.9; singleton mean = 40.8 seconds; SEM = 4.8). Higher concentrations of several toxicants were observed in dyad-produced smoke. Discussion: Dyad smoking may increase smoke toxicant content, likely due to the dyad’s shorter IPIs and greater puff number. More work is needed to understand if group waterpipe smoking alters the health risks of waterpipe tobacco smoking. Implications: This study is the first to measure toxicants in smoke generated from a waterpipe when used by a dyad. Relative to smoke generated by a singleton, dyad smoke had higher concentration of some toxicants. These

  4. The chemical exposure toxicity space (CETS) model: Displaying exposure time, aqueous and organic concentration, activity, and onset of toxicity.

    PubMed

    Mackay, Donald; Celsie, Alena K D; Parnis, J Mark; McCarty, Lynn S; Arnot, Jon A; Powell, David E

    2017-05-01

    A 1-compartment toxicokinetic model is used to characterize the chemical exposure toxicity space (CETS), providing a novel graphic tool that can aid in the design of aquatic toxicity tests for fish and for interpreting their results. The graph depicts the solution to the differential equation describing the uptake kinetics of a chemical by a modeled fish under conventional bioassay conditions. The model relates the exposure concentration in the water to a dimensionless time and the onset of toxicity as determined by an estimated or assumed critical body residue or incipient lethal aqueous concentration. These concentration graphs are specific to each chemical and exposure and organism parameters and clearly demonstrate differences in toxicity between chemicals and how factors such as hydrophobicity influence the toxic endpoint. The CETS plots can also be used to assess bioconcentration test conditions to ensure that concentrations are well below toxic levels. Illustrative applications are presented using a recent set of high-quality toxicity data. Conversion of concentrations to chemical activities in the plots enables results for different baseline toxicants to be superimposed. For chemicals that have different modes of toxic action, the increased toxicity then becomes apparent. Implications for design and interpretation of aquatic toxicity tests are discussed. The model, and pictorial visualization of the time-course of aquatic toxicity tests, may contribute to improvements in test design, implementation, and interpretation, and to reduced animal usage. Environ Toxicol Chem 2017;36:1389-1396. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

  5. Group Waterpipe Tobacco Smoking Increases Smoke Toxicant Concentration.

    PubMed

    Ramôa, Carolina P; Shihadeh, Alan; Salman, Rola; Eissenberg, Thomas

    2016-05-01

    Waterpipe tobacco smoking is a global health concern. Laboratory research has focused on individual waterpipe users while group use is common. This study examined user toxicant exposure and smoke toxicant yield associated with individual and group waterpipe smoking. Twenty-two pairs of waterpipe smokers used a waterpipe individually and as a dyad. Before and after smoking, blood was sampled and expired carbon monoxide (CO) measured; puff topography was recorded throughout. One participant from each pair was selected randomly and their plasma nicotine and expired air CO concentrations were compared when smoking alone to when smoking as part of a dyad. Recorded puff topography was used to machine-produce smoke that was analyzed for toxicant content. There was no difference in mean plasma nicotine concentration when an individual smoked as part of a dyad (mean = 14.9 ng/ml; standard error of the mean [SEM] = 3.0) compared to when smoking alone (mean = 10.0 ng/ml; SEM = 1.5). An individual smoking as part of as a dyad had, on average, lower CO (mean = 15.8 ppm; SEM = 2.0) compared to when smoking alone (mean= 21.3 ppm; SEM = 2.7). When two participants smoked as a dyad they took, on average, more puffs (mean = 109.8; SEM = 7.6) than a singleton smoker (mean = 77.7; SEM = 8.1) and a shorter interpuff interval (IPI; dyad mean = 23.8 seconds; SEM = 1.9; singleton mean = 40.8 seconds; SEM = 4.8). Higher concentrations of several toxicants were observed in dyad-produced smoke. Dyad smoking may increase smoke toxicant content, likely due to the dyad's shorter IPIs and greater puff number. More work is needed to understand if group waterpipe smoking alters the health risks of waterpipe tobacco smoking. This study is the first to measure toxicants in smoke generated from a waterpipe when used by a dyad. Relative to smoke generated by a singleton, dyad smoke had higher concentration of some toxicants. These differences may be attributed to differences in puffing behavior

  6. Concentrations, sources and human health risk of inhalation exposure to air toxics in Edmonton, Canada.

    PubMed

    Bari, Md Aynul; Kindzierski, Warren B

    2017-04-01

    With concern about levels of air pollutants in recent years in the Capital Region of Alberta, an investigation of ambient concentrations, sources and potential human health risk of hazardous air pollutants (HAPs) or air toxics was undertaken in the City of Edmonton over a 5-year period (2009-2013). Mean concentrations of individual HAPs in ambient air including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and trace metals ranged from 0.04 to 1.73 μg/m 3 , 0.01-0.54 ng/m 3 , and 0.05-3.58 ng/m 3 , respectively. Concentrations of benzene, naphthalene, benzo(a)pyrene (BaP), arsenic, manganese and nickel were far below respective annual Alberta Ambient Air Quality Objectives. Carcinogenic and non-carcinogenic risk of air toxics were also compared with risk levels recommended by regulatory agencies. Positive matrix factorization identified six air toxics sources with traffic as the dominant contributor to total HAPs (4.33 μg/m 3 , 42%), followed by background/secondary organic aerosol (SOA) (1.92 μg/m 3 , 25%), fossil fuel combustion (0.92 μg/m 3 , 11%). On high particulate air pollution event days, local traffic was identified as the major contributor to total HAPs compared to background/SOA and fossil fuel combustion. Carcinogenic risk values of traffic, background/SOA and metals industry emissions were above the USEPA acceptable level (1 × 10 -6 ), but below a tolerable risk (1 × 10 -4 ) and Alberta benchmark (1 × 10 -5 ). These findings offer useful preliminary information about current ambient air toxics levels, dominant sources and their potential risk to public health; and this information can support policy makers in the development of appropriate control strategies if required. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Global concentration additivity and prediction of mixture toxicities, taking nitrobenzene derivatives as an example.

    PubMed

    Li, Tong; Liu, Shu-Shen; Qu, Rui; Liu, Hai-Ling

    2017-10-01

    The toxicity of a mixture depends not only on the mixture concentration level but also on the mixture ratio. For a multiple-component mixture (MCM) system with a definite chemical composition, the mixture toxicity can be predicted only if the global concentration additivity (GCA) is validated. The so-called GCA means that the toxicity of any mixture in the MCM system is the concentration additive, regardless of what its mixture ratio and concentration level. However, many mixture toxicity reports have usually employed one mixture ratio (such as the EC 50 ratio), the equivalent effect concentration ratio (EECR) design, to specify several mixtures. EECR mixtures cannot simulate the concentration diversity and mixture ratio diversity of mixtures in the real environment, and it is impossible to validate the GCA. Therefore, in this paper, the uniform design ray (UD-Ray) was used to select nine mixture ratios (rays) in the mixture system of five nitrobenzene derivatives (NBDs). The representative UD-Ray mixtures can effectively and rationally describe the diversity in the NBD mixture system. The toxicities of the mixtures to Vibrio qinghaiensis sp.-Q67 were determined by the microplate toxicity analysis (MTA). For each UD-Ray mixture, the concentration addition (CA) model was used to validate whether the mixture toxicity is additive. All of the UD-Ray mixtures of five NBDs are global concentration additive. Afterwards, the CA is employed to predict the toxicities of the external mixtures from three EECR mixture rays with the NOEC, EC 30 , and EC 70 ratios. The predictive toxicities are in good agreement with the experimental toxicities, which testifies to the predictability of the mixture toxicity of the NBDs. Copyright © 2017. Published by Elsevier Inc.

  8. Honeybee (Apis cerana) foraging responses to the toxic honey of Tripterygium hypoglaucum (Celastraceae): changing threshold of nectar acceptability.

    PubMed

    Tan, K; Guo, Y H; Nicolson, S W; Radloff, S E; Song, Q S; Hepburn, H R

    2007-12-01

    To investigate honeybee foraging responses to toxic nectar, honey was collected from Apis cerana colonies in the Yaoan county of Yunnan Province, China, during June, when flowers of Tripterygium hypoglaucum were the main nectar source available. Pollen analysis confirmed the origin of the honey, and high-performance liquid chromatography showed the prominent component triptolide to be present at a concentration of 0.61 mug/g +/- 0.11 SD. In cage tests that used young adult worker bees, significantly more of those provided with a diet of T. hypoglaucum honey mixed with sugar powder (1:1) died within 6 d (68.3%) compared to control groups provided with normal honey mixed with sugar powder (15.8%). Honeybees were trained to visit feeders that contained honey of T. hypoglaucum (toxic honey) as the test group and honey of Vicia sativa or Elsholtzia ciliata as control groups (all honeys diluted 1:3 with water). Bees preferred the feeders with normal honey to those with toxic honey, as shown by significantly higher visiting frequencies and longer imbibition times. However, when the feeder of normal honey was removed, leaving only honey of T. hypoglaucum, the foraging bees returned to the toxic honey after a few seconds of hesitation, and both visiting frequency and imbibition time increased to values previously recorded for normal honey. Toxic honey thus became acceptable to the bees in the absence of other nectar sources.

  9. Prediction of toxic metals concentration using artificial intelligence techniques

    NASA Astrophysics Data System (ADS)

    Gholami, R.; Kamkar-Rouhani, A.; Doulati Ardejani, F.; Maleki, Sh.

    2011-12-01

    Groundwater and soil pollution are noted to be the worst environmental problem related to the mining industry because of the pyrite oxidation, and hence acid mine drainage generation, release and transport of the toxic metals. The aim of this paper is to predict the concentration of Ni and Fe using a robust algorithm named support vector machine (SVM). Comparison of the obtained results of SVM with those of the back-propagation neural network (BPNN) indicates that the SVM can be regarded as a proper algorithm for the prediction of toxic metals concentration due to its relative high correlation coefficient and the associated running time. As a matter of fact, the SVM method has provided a better prediction of the toxic metals Fe and Ni and resulted the running time faster compared with that of the BPNN.

  10. Biological treatment and toxicity of low concentrations of oily wastewater (bilgewater).

    PubMed

    Stamper, David M; Montgomery, Michael T

    2008-08-01

    The biodegradability and toxicity of low concentrations of oily wastewater (bilgewater) were tested under simulated sanitary wastewater treatment conditions. This was done to establish the feasibility of a combined shipboard oily and nonoily wastewater treatment system. The biodegradability of oily wastewater was determined by proxy; 14C-labeled dodecane, toluene, and phenanthrene (representing alkane, aromatic, and polyaromatic compounds, respectively) were mineralized in petroleum fuels and lubricants. We found that low concentrations of oily wastewater components were mineralized, even in the presence of more abundant substrates (such as synthetic graywater, containing vegetable oil, detergent, gelatin, and starch). The toxic effects of diesel fuel and several other components of oily wastewater (such as surfactants and a synthetic lubricant) on a naïve wastewater assemblage was also tested. In concentrations much higher than would be expected under normal shipboard conditions, we found no evidence of toxic effects of the bilgewater compounds tested. Thus, a combined shipboard bilgewater and sanitary wastewater system might be feasible.

  11. Concentration rather than dose defines the local brain toxicity of agents that are effectively distributed by convection-enhanced delivery.

    PubMed

    Zhang, Rong; Saito, Ryuta; Mano, Yui; Kanamori, Masayuki; Sonoda, Yukihiko; Kumabe, Toshihiro; Tominaga, Teiji

    2014-01-30

    Convection-enhanced delivery (CED) has been developed as a potentially effective drug-delivery strategy into the central nervous system. In contrast to systemic intravenous administration, local delivery achieves high concentration and prolonged retention in the local tissue, with increased chance of local toxicity, especially with toxic agents such as chemotherapeutic agents. Therefore, the factors that affect local toxicity should be extensively studied. With the assumption that concentration-oriented evaluation of toxicity is important for local CED, we evaluated the appearance of local toxicity among different agents after delivery with CED and studied if it is dose dependent or concentration dependent. Local toxicity profile of chemotherapeutic agents delivered via CED indicates BCNU was dose-dependent, whereas that of ACNU was concentration-dependent. On the other hand, local toxicity for doxorubicin, which is not distributed effectively by CED, was dose-dependent. Local toxicity for PLD, which is extensively distributed by CED, was concentration-dependent. Traditional evaluation of drug induced toxicity was dose-oriented. This is true for systemic intravascular delivery. However, with local CED, toxicity of several drugs exacerbated in concentration-dependent manner. From our study, local toxicity of drugs that are likely to distribute effectively tended to be concentration-dependent. Concentration rather than dose may be more important for the toxicity of agents that are effectively distributed by CED. Concentration-oriented evaluation of toxicity is more important for CED. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Concentration-response data on toxicity of pyrolysis gases from some natural and synthetic polymers

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Huttlinger, N. V.

    1978-01-01

    Concentration-response data are presented on the toxic effects of the pyrolysis gases from some natural and synthetic polymers, using the toxicity screening test method developed at the University of San Francisco. The pyrolysis gases from wool, red oak, Douglas fir, polycaprolactam, polyether sulfone, polyaryl sulfone, and polyphenylene sulfide appeared to exhibit the concentration-response relationships commonly encountered in toxicology. Carbon monoxide seemed to be an important toxicant in the pyrolysis gases from red oak, Douglas fir, and polycaprolactam, but did not appear to have been the principal toxicant in the pyrolysis gases from polyether sulfone and polyphenylene sulfide.

  13. Heavy metal concentrations and toxicity in water and sediment from stormwater ponds and sedimentation tanks.

    PubMed

    Karlsson, Kristin; Viklander, Maria; Scholes, Lian; Revitt, Mike

    2010-06-15

    Sedimentation is a widely used technique in structural best management practices to remove pollutants from stormwater. However, concerns have been expressed about the environmental impacts that may be exerted by the trapped pollutants. This study has concentrated on stormwater ponds and sedimentation tanks and reports on the accumulated metal concentrations (Cd, Cr, Ni, Pb, and Zn) and the associated toxicity to the bacteria Vibrio fischeri. The metal concentrations are compared with guidelines and the toxicity results are assessed in relation to samples for which metal concentrations either exceed or conform to these values. The water phase metal concentrations were highest in the ponds whereas the sedimentation tanks exhibited a distinct decrease towards the outlet. However, none of the water samples demonstrated toxicity even though the concentrations of Cu, Pb, and Zn exceeded the threshold values for the compared guidelines. The facilities with higher traffic intensities had elevated sediment concentrations of Cr, Cu, Ni, and Zn which increased towards the outlet for the sedimentation tanks in agreement with the highest percentage of fine particles. The sediments in both treatment facilities exhibited the expected toxic responses in line with their affinity for heavy metals but the role of organic carbon content is highlighted. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Self-tracking solar concentrator with an acceptance angle of 32°.

    PubMed

    Zagolla, Volker; Dominé, Didier; Tremblay, Eric; Moser, Christophe

    2014-12-15

    Solar concentration has the potential to decrease the cost associated with solar cells by replacing the receiving surface aperture with cheaper optics that concentrate light onto a smaller cell aperture. However a mechanical tracker has to be added to the system to keep the concentrated light on the size reduced solar cell at all times. The tracking device itself uses energy to follow the sun's position during the day. We have previously shown a mechanism for self-tracking that works by making use of the infrared energy of the solar spectrum, to activate a phase change material. In this paper, we show an implementation of a working 53 x 53 mm(2) self-tracking system with an acceptance angle of 32° ( ± 16°). This paper describes the design optimizations and upscaling process to extend the proof-of-principle self-tracking mechanism to a working demonstration device including the incorporation of custom photodiodes for system characterization. The current version demonstrates an effective concentration of 3.5x (compared to 8x theoretical) over 80% of the desired acceptance angle. Further improvements are expected to increase the efficiency of the system and open the possibility to expand the device to concentrations as high as 200x (C(geo) = 400x, η = 50%, for a solar cell matched spectrum).

  15. Wide acceptance angle, high concentration ratio, optical collector

    NASA Technical Reports Server (NTRS)

    Kruer, Mark Arthur (Inventor)

    1990-01-01

    The invention is directed to an optical collector requiring a wide acceptance angle, and a high concentration ratio. The invention is particularly adapted for use in solar collectors of cassegrain design. The optical collector system includes a parabolic circular concave primary mirror and a hyperbolic circular convex secondary mirror. The primary mirror includes a circular hole located at its center wherein a solar collector is located. The mirrored surface of the secondary mirror has three distinct zones: a center circle, an on-axis annulus, and an off-axis section. The parabolic shape of the primary mirror is chosen so that the primary mirror reflects light entering the system on-axis onto the on-axis annulus. A substantial amount of light entering the system off-axis is reflected by the primary mirror onto either the off-axis section or onto the center circle. Subsequently, the off-axis sections reflect the off-axis light toward the solar collector. Thus, off-axis light is captured which would otherwise be lost to the system. The novelty of the system appears to lie in the configuration of the primary mirror which focuses off-axis light onto an annular portion of the secondary mirror to enable capture thereof. This feature results in wide acceptance angle and a high concentration ratio, and also compensates for the effects of non-specular reflection, and enables a cassegrain configuration to be used where such characteristics are required.

  16. Effects of temperature and oxygen concentration in sediment toxicity testing.

    PubMed

    Airas, Sari; Leppänen, Matti; Kukkonen, Jussi V K

    2008-07-01

    Joint effects of temperature and oxygen concentrations for the results of sediment toxicity tests were studied at 10 and 20 degrees C with 40% and 80% dissolved oxygen (DO) saturation. Growth, feeding rate, and reproduction of Lumbriculus variegatus (Oligochaete) and growth, emergence, and survival of Chironomus riparius (Diptera) were tested in a polluted and in a reference sediment. Both the feeding of L. variegatus and the emergence of C. riparius were significantly retarded at low temperature. Additionally, differences in the sex ratio of the emerged adults of C. riparius were observed. The oxygen concentration alone did not have any significant effect on the endpoints, but significant combined effects of polluted sediment and low DO were observed on the biomass of L. variegatus. The standard sediment toxicity tests might offer only limited data for risk assessment of contaminated sediments at sites where the actual conditions largely differ from the laboratory conditions.

  17. Hydrogen concentrations as an indicator of the predominant terminal electron-accepting reactions in aquatic sediments

    USGS Publications Warehouse

    Lovley, D.R.; Goodwin, S.

    1988-01-01

    Factors controlling the concentration of dissolved hydrogen gas in anaerobic sedimentary environments were investigated. Results, presented here or previously, demonstrated that, in sediments, only microorganisms catalyze the oxidation of H2 coupled to the reduction of nitrate, Mn(IV), Fe(III), sulfate, or carbon dioxide. Theoretical considerations suggested that, at steady-state conditions, H2 concentrations are primarily dependent upon the physiological characteristics of the microorganism(s) consuming the H2 and that organisms catalyzing H2 oxidation, with the reduction of a more electrochemically positive electron acceptor, can maintain lower H2 concentrations than organisms using electron acceptors which yield less energy from H2 oxidation. The H2 concentrations associated with the specified predominant terminal electron-accepting reactions in bottom sediments of a variety of surface water environments were: methanogenesis, 7-10 nM; sulfate reduction, 1-1.5 nM; Fe(III) reduction, 0.2 nM; Mn(IV) or nitrate reduction, less than 0.05 nM. Sediments with the same terminal electron acceptor for organic matter oxidation had comparable H2 concentrations, despite variations in the rate of organic matter decomposition, pH, and salinity. Thus, each terminal electron-accepting reaction had a unique range of steady-state H2 concentrations associated with it. Preliminary studies in a coastal plain aquifer indicated that H2 concentrations also vary in response to changes in the predominant terminal electron-accepting process in deep subsurface environments. These studies suggest that H2 measurements may aid in determining which terminal electron-accepting reactions are taking place in surface and subsurface sedimentary environments. ?? 1988.

  18. Analysis of Mobile Source Air Toxics (MSATS)–Near-Road VOC and CarbonylConcentrations

    EPA Science Inventory

    This presentation examines data from a year-long study of measured near-road mobile source air toxic (MSAT) concentrations and compares these data with modeled 2005 National Air Toxic Assessment (NATA) results. Field study measurements were collected during a field campaign in ...

  19. Toxic effects of lead on biochemical and histological alterations in green mussel (Perna viridis) induced by environmentally relevant concentrations.

    PubMed

    Hariharan, G; Purvaja, R; Ramesh, R

    2014-01-01

    Acute and chronic toxicity tests were conducted on green mussel (Perna viridis) to determine the adverse effects of lead (Pb). Exposure of organisms to acute toxicity test for 96 h and lethal concentration (LC(50)) was the endpoint of the test. Acute toxicity for 96-h LC(50) and 95% confidence intervals of P. viridis was 2.62 ± 0.12 (2.62-3.24) mg/L Pb. Chronic toxicity tests revealed that survival of exposed organisms decreased with elevated exposure concentrations. No-observed-effect concentration (NOEC) and lowest-observed-effect concentration (LOEC) were calculated based on survival of test organisms. Results of this study demonstrated an increase in toxicity in test organisms with rise in exposure time and concentration. In this study, histology and biochemical enzymes, namely, catalase, reduced glutathione, glutathione S-transferase, and lipid peroxides, were correlated with chronic value and survival endpoints of P. viridis after chronic exposure to Pb. Biochemical and histological responses to different concentrations of Pb were assessed and significant differences were observed between control and increasing exposure concentrations. Biomarker studies in internal organs confirmed that the observed changes are due to adverse effects of Pb. This assessment of toxicity was the first step to determining the seawater quality criteria for marine organisms.

  20. Predicting the toxicity of sediment-associated trace metals with simultaneously extracted trace metal: Acid-volatile sulfide concentrations and dry weight-normalized concentrations: A critical comparison

    USGS Publications Warehouse

    Long, E.R.; MacDonald, D.D.; Cubbage, J.C.; Ingersoll, C.G.

    1998-01-01

    The relative abilities of sediment concentrations of simultaneously extracted trace metal: acid-volatile sulfide (SEM: AVS) and dry weight-normalized trace metals to correctly predict both toxicity and nontoxicity were compared by analysis of 77 field-collected samples. Relative to the SEM:AVS concentrations, sediment guidelines based upon dry weight-normalized concentrations were equally or slightly more accurate in predicting both nontoxic and toxic results in laboratory tests.

  1. Dechlorination kinetics of TCE at toxic TCE concentrations: Assessment of different models.

    PubMed

    Haest, P J; Springael, D; Smolders, E

    2010-01-01

    The reductive dechlorination of trichloroethene (TCE) in a TCE source zone can be self-inhibited by TCE toxicity. A study was set up to examine the toxicity of TCE in terms of species specific degradation kinetics and microbial growth and to evaluate models that describe this self-inhibition. A batch experiment was performed using the TCE dechlorinating KB-1 culture at initial TCE concentrations ranging from 0.04mM to saturation (8.4mM). Biodegradation activity was highest at 0.3mM TCE and no activity was found at concentrations from 4 to 8mM. Species specific TCE and cis-DCE (cis-dichloroethene) degradation rates and Dehalococcoides numbers were modeled with Monod kinetics combined with either Haldane inhibition or a log-logistic dose-response inhibition on these rates. The log-logistic toxicity model appeared the most appropriate model and predicts that the species specific degradation activities are reduced by a factor 2 at about 1mM TCE, respectively cis-DCE. However, the model showed that the inhibitive effects on the time for TCE to ethene degradation are a complex function of degradation kinetics and the initial cell densities of the dechlorinating species. Our analysis suggests that the self-inhibition on biodegradation cannot be predicted by a single concentration threshold without information on the cell densities.

  2. Assessment of sediment toxicity and chemical concentrations in the San Diego Bay region, California, USA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fairey, R.; Roberts, C.; Jacobi, M.

    1998-08-01

    Sediment quality within San Diego Bay, Mission Bay, and the Tijuana River Estuary of California was investigated as part of an ongoing statewide monitoring effort (Bay Protection and Toxic Cleanup Program). Study objectives were to determine the incidence, spatial patterns, and spatial extent of toxicity in sediments and porewater; the concentration and distribution of potentially toxic anthropogenic chemicals; and the relationships between toxicity and chemical concentrations. Rhepoxynius abronius survival bioassays, grain size, and total organic carbon analyses were performed on 350 sediment samples. Strongylocentrotus purpuratus development bioassays were performed on 164 pore-water samples. Toxicity was demonstrated throughout the San Diegomore » Bay region, with increased incidence and concordance occurring in areas of industrial and shipping activity. Trace metal and trace synthetic organic analyses were performed on 229 samples. Copper, zinc, mercury, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlordane were found to exceed ERM (effects range median) or PEL (probable effects level) sediment quality guidelines and were considered the six major chemicals or chemical groups of concern. Statistical analysis of the relationships between amphipod toxicity, bulk phase sediment chemistry, and physical parameters demonstrated few significant linear relationships. Significant differences in chemical levels were found between toxic and nontoxic responses using multivariate and univariate statistics. Potential sources of anthropogenic chemicals were discussed.« less

  3. Critical predicted no effect concentrations (PNECs) should not be based on a single toxicity test.

    PubMed

    Chapman, Peter M; Elphick, James R

    2015-05-01

    Predicted no-effect concentrations (PNECs), which represent the concentration of a substance below which an unacceptable effect most likely will not occur, are widely used for risk assessment and in environmental policy and regulation. They are typically based on single-species laboratory toxicity tests; often, a single test result for the most sensitive endpoints drives the derivation of a PNEC. In the present study, the authors provide a case study emphasizing the importance of determining the reliability of those most sensitive endpoints. Five 21-d Daphnia magna toxicity tests conducted using the same procedures by 2 laboratories gave 20% inhibitory concentration responses to a specific ionic composition of total dissolved solids that varied from 684 mg/L to more than 1510 mg/L. The concentration-response curve was shallow; thus, these differences could have been attributable to chance alone. The authors strongly recommend that the most sensitive endpoints that determine PNECs not be based on a single toxicity test result but rather on the geometric mean of at least 3 test results to adequately assess and bound test variability, especially when the concentration-response curve is shallow. © 2015 SETAC.

  4. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-02

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  5. Nanoscale zerovalent iron (nZVI) at environmentally relevant concentrations induced multigenerational reproductive toxicity in Caenorhabditis elegans.

    PubMed

    Yang, Ying-Fei; Chen, Pei-Jen; Liao, Vivian Hsiu-Chuan

    2016-05-01

    Nanoscale zerovalent iron (nZVI) is widely used with large scale for environmental remediation for in situ or ex situ applications. The potential impact of nZVI on biota at environmentally relevant concentrations needs to be elucidated. In this study, the reproductive toxicities of three irons species: carboxymethyl cellulose (CMC)-stabilized nZVI, nanoscale iron oxide (nFe3O4), and ferrous ion (Fe(II)aq) in the soil-dwelling nematode Caenorhabditis elegans were examined. In addition, the generational transfer of reproductive toxicity of CMC-nZVI on C. elegans was investigated. The results showed that CMC-nZVI, nFe3O4, and Fe(II)aq did not cause significant mortality after 24 h exposure at the examined concentrations. Reproductive toxicity assays revealed that CMC-nZVI, nFe3O4, and Fe(II)aq significantly decreased offsprings in parental generation (F0) in accompany with the increased intracellular reactive oxygen species (ROS). Furthermore, the reproductive toxicity of CMC-nZVI at environmentally relevant concentrations was transferrable from the F0 to the F1 and F2 generations, but then recovered in the F3 and F4 generations. Further evidence showed that total irons were accumulated in the F0 and F1 generations of C. elegans after CMC-nZVI parental exposure. This study demonstrated that environmentally relevant concentrations of CMC-nZVI induced multigenerational reproductive toxicity which can be ascribed to its high production of ROS in F0 generation, toxicity of Fe(II)aq, and iron accumulation in C. elegans. Since nZVI is widely used for environmental remediation, considering the multigenerational toxicity, this study thus implicates a potential environmental risk of nZVI-induced nanotoxicity in the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Pesticide concentrations in water and sediment and associated invertebrate toxicity in Del Puerto and Orestimba Creeks, California, 2007-2008.

    PubMed

    Ensminger, Michael; Bergin, Rick; Spurlock, Frank; Goh, Kean S

    2011-04-01

    The California's San Joaquin River and its tributaries including Orestimba (ORC) and Del Puerto (DPC) Creeks are listed on the 2006 US EPA Clean Water Act §303(d) list for pesticide impairment. From December 2007 through June 2008, water and sediment samples were collected from both creeks in Stanislaus County to determine concentrations of organophosphorus (OP) and pyrethroid insecticides and to identify toxicity to Ceriodaphnia dubia and Hyalella azteca. OPs were detected in almost half (10 of 21) of the water samples, at concentrations from 0.005 to 0.912 μg L(-1). Diazinon was the most frequently detected OP, followed by chlorpyrifos and dimethoate. Two water samples were toxic to C. dubia; based on median lethal concentrations (LC50), chlorpyrifos was likely the cause of this toxicity. Pyrethroids were detected more frequently in sediment samples (18 detections) than in water samples (three detections). Pyrethroid concentrations in water samples ranged from 0.005 to 0.021 μg L(-1). These concentrations were well below reported C. dubia LC50s, and toxicity was not observed in laboratory bioassays. Cyfluthrin, bifenthrin, esfenvalerate, and λ-cyhalothrin were detected in sediment samples at concentrations ranging from 1.0 to 74.4 ng g(-1), dry weight. At DPC, all but one sediment sample caused 100% toxicity to H. azteca. Based on estimated toxicity units (TUs), bifenthrin was likely responsible for this toxicity and λ-cyhalothrin also contributed. At ORC, survival of H. azteca was significantly reduced in four of the 11 sediment samples. However, pyrethroids were detected in only two of these samples. Based on TUs, bifenthrin and λ-cyhalothrin likely contributed to the toxicity.

  7. CONCENTRATIONS OF TOXIC AIR POLLUTANTS IN THE U.S. SIMULATED BY AN AIR QUALITY MODEL

    EPA Science Inventory

    As part of the US National Air Toxics Assessment, we have applied the Community Multiscale Air Quality Model, CMAQ, to study the concentrations of twenty gas-phase, toxic, hazardous air pollutants (HAPs) in the atmosphere over the continental United States. We modified the Carbo...

  8. Cefepime plasma concentrations and clinical toxicity: a retrospective cohort study.

    PubMed

    Huwyler, T; Lenggenhager, L; Abbas, M; Ing Lorenzini, K; Hughes, S; Huttner, B; Karmime, A; Uçkay, I; von Dach, E; Lescuyer, P; Harbarth, S; Huttner, A

    2017-07-01

    Cefepime remains an important antibiotic for severe bacterial infections, yet some meta-analyses have shown elevated mortality among patients randomized to it. Therapeutic drug monitoring (TDM) of β-lactam antibiotics is increasing, but optimal plasma concentrations remain unknown. We examined clinical outcomes of patients undergoing cefepime TDM in an initial effort to define the drug's toxicity threshold. In this single-centre retrospective cohort study, we enrolled all adult hospitalized patients receiving cefepime and undergoing TDM from January 2013 through July 2016. The primary outcome was the incidence of clinical toxicity; a secondary outcome was clinical failure. Plasma samples were analysed via high-performance liquid chromatography with ultraviolet detection. A total of 161 cefepime concentrations were drawn from 93 patients. Roughly half (82/161, 51%) and one-third (49/161, 30%) were trough and steady-state levels from patients receiving intermittent and continuous infusions, respectively; median concentrations were 17.6 mg/L (IQR 9.7-35.2) and 29.2 mg/L (IQR 18.9-45.9). Ten patients (11%) experienced a neurologic event considered at least possibly related to cefepime; neurotoxicity was associated with poorer renal function (median creatinine clearance 54 (IQR 39-97) vs. 75 mL/min/1.73 2 (IQR 44-104)) and longer cefepime durations (mean 8.3 (SD±6.7) vs. 13.3 days (± 14.2), p = 0.071). Patients with trough levels >20 mg/L had a fivefold higher risk for neurologic events (OR 5.05, 95% CI 1.3-19.8). Neurotoxicity potentially related to cefepime occurred at plasma concentrations >35 mg/L. For those receiving intermittent infusions, trough concentrations >20 mg/L should be avoided until further information is available from prospective studies. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  9. The potentiation effect makes the difference: non-toxic concentrations of ZnO nanoparticles enhance Cu nanoparticle toxicity in vitro.

    PubMed

    Li, Lingxiangyu; Fernández-Cruz, María Luisa; Connolly, Mona; Conde, Estefanía; Fernández, Marta; Schuster, Michael; Navas, José María

    2015-02-01

    Here we examined whether the addition of a non-toxic concentration (6.25 μg/mL) of zinc oxide nanoparticles (ZnONPs: 19, 35 and 57 nm, respectively) modulates the cytotoxicity of copper nanoparticles (CuNPs, 63 nm in size) in the human hepatoma cell line HepG2. The cytotoxic effect of CuNPs on HepG2 cells was markedly enhanced by the ZnONPs, the largest ZnONPs causing the highest increase in toxicity. However, CuNPs cytotoxicity was not affected by co-incubation with medium containing only zinc ions, indicating the increase in toxicity might be attributed to the particle form of ZnONPs. Transmission electron microscopy (TEM) revealed the presence of CuNPs and ZnONPs inside the cells co-exposed to both types of NP and outflow of cytoplasm through the damaged cell membrane. Inductively coupled plasma mass spectrometry (ICP-MS) determined an increase in the concentration of zinc and a decrease in that of copper in co-exposed cells. On the basis of these results, we propose that accumulation of large numbers of ZnONPs in the cells alters cellular membranes and the cytotoxicity of CuNPs is increased. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Cadmium toxicity at low concentration on rabbit spermatozoa motility, morphology and membrane integrity in vitro.

    PubMed

    Roychoudhury, Shubhadeep; Massanyi, Peter; Bulla, Jozef; Choudhury, Manabendra Dutta; Lukac, Norbert; Filipejova, Terezia; Trandzik, Jozef; Toman, Robert; Almasiova, Viera

    2010-09-01

    In this study the effect of cadmium on various parameters of spermatozoa motility, morphology as well as on the spermatozoa membrane integrity in rabbits was analyzed in vitro, experimental concentrations ranging from 0.62 to 0.98 micro g CdCl(2)/mL. Pooled rabbit (n = 5) semen was cultured in vitro with cadmium and subsequently diluted to various experimental concentrations apart from control which received no cadmium exposure. Using computer assisted semen analysis method (CASA) we detected decrease of total motility with in the higher concentration range at Time 0. However, with increasing time (after 1 and 2 h of culture), cadmium exerted deleterious effect leading to significant motility reduction in comparison to control. A similar trend was exhibited in case of progressive motility, too. Most of the spermatozoa distance and velocity parameters detected no significant change in comparison to control at the beginning of culture (Time 0), although the toxic effect became significant (P < 0.05) with the passage of culture time (Times 1 and 2 h) in all concentrations. Analysis of spermatozoa morphology detected significant (P < 0.05) alterations at higher concentrations. At higher concentrations acrosomal changes, head without flagellum/separated flagellum, broken flagellum and other abnormalities were significantly higher (P < 0.05), while knob-twisted flagellum and small heads differed significantly (P < 0.05) in comparison to control at all concentrations. In regards to flagellum torso, flagellum ball and retention of cytoplasmic drop statistically higher values (P < 0.05) were noted at the maxium experimental concentration only. Annexin analysis for detection of spermatozoa with disordered membranes revealed higher occurrence of positive spermatozoa in cadmium exposed groups. Annexin-positive reactions suggested alterations in anterior part of head (acrosome) and in flagellum (mitochondrial segment) of spermatozoa. This paper underlines that cadmium is highly

  11. Evaluation of toxicity and estrogenicity of the landfill-concentrated leachate during advanced oxidation treatment: chemical analyses and bioanalytical tools.

    PubMed

    Wang, Guifang; Lu, Gang; Zhao, Jiandi; Yin, Pinghe; Zhao, Ling

    2016-08-01

    Landfill-concentrated leachate from membrane separation processes is a potential pollution source for the surroundings. In this study, the toxicity and estrogenicity potentials of concentrated leachate prior to and during UV-Fenton and Fenton treatments were assessed by a combination of chemical (di (2-ethylhexyl) phthalate and dibutyl phthalate were chosen as targets) and biological (Daphnia magna, Chlorella vulgaris, and E-screen assay) analyses. Removal efficiencies of measured di (2-ethylhexyl) phthalate and dibutyl phthalate were more than 97 % after treatment with the two methods. Biological tests showed acute toxicity effects on D. magna tests in untreated concentrated leachate samples, whereas acute toxicity on C. vulgaris tests was not observed. Both treatment methods were found to be efficient in reducing acute toxicity effects on D. magna tests. The E-screen test showed concentrated leachate had significant estrogenicity, UV-Fenton and Fenton treatment, especially the former, were effective methods for reducing estrogenicity of concentrated leachate. The EEQchem (estradiol equivalent concentration) of all samples could only explain 0.218-5.31 % range of the EEQbio. These results showed that UV-Fenton reagent could be considered as a suitable method for treatment of concentrated leachate, and the importance of the application of an integrated (biological + chemical) analytical approach for a comprehensive evaluation of treatment suitability.

  12. PAHs concentration and toxicity in organic solvent extracts of atmospheric particulate matter and sea sediments.

    PubMed

    Ozaki, Noriatsu; Takeuchi, Shin-ya; Kojima, Keisuke; Kindaichi, Tomonori; Komatsu, Toshiko; Fukushima, Takehiko

    2012-01-01

    The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources.

  13. LARGE-SCALE PREDICTIONS OF MOBILE SOURCE CONTRIBUTIONS TO CONCENTRATIONS OF TOXIC AIR POLLUTANTS

    EPA Science Inventory

    This presentation shows concentrations and deposition of toxic air pollutants predicted by a 3-D air quality model, the Community Multi Scale Air Quality (CMAQ) modeling system. Contributions from both on-road and non-road mobile sources are analyzed.

  14. Study on the Effect of Heavy metals toxicity according to changing Hardness concentration using D.magna

    NASA Astrophysics Data System (ADS)

    Chun Sang, H.

    2016-12-01

    n order to determine and prevent the number of ecological effects of heavy metals in the materials, we have to accurately measure the heavy metals present in the water-based protection ecosystems and may determine the effects to humans. Heavy metals occurred in the industrial effluent which is a state in which the monitor, based on the emission standards are made by the Ministry of Environment and managed and waste water contained Copper, Zinc, lead, etc. These heavy metals are able to express the toxic effects only when present in the free-ions in the aqueous condition, which appears differently affected by the degree to hardness change in accordance with the season, precipitation. Generally changing hardness concentration can not precisely evaluate toxic effects of heavy metals in the water system. Anderson announced a study on bioassay for heavy metals from industrial waste water using Daphnia magna(Anderson, 1944, 1948). Breukelman published study the resitivity difference for the mercury Chloride(HgCl2). Braudouin(1974) compared the zooplankton(Daphnia sp.) acute toxicity of the different heavy metals and confirmed the sensitivity. Shcherban(1979) presented for toxicity evaluation results for the heavy metal of the Daphnia magna according to different temperature conditions. In the United States Environmental Protection Agency(EPA) established a standard test method for water fleas, managed and supervised water ecosystems, and announced the adoption of a bioassay standard method. This study was performed to evaluate acute inhibition using the Daphnia magna for the biological effect of heavy metal ions in water-based toxicity in the hardness change. Evaluation methods were conducted in EPA Water Quality process test criteria. TU(Toxic Unit), NOEC (No Observable Effect Concentration), LOEC (Lowest Observable Effect Concentration), EC50 (Median Effective Concentration) was calculated by Toxcalc 5.0 Program. Keywords : D. magna, Hardness, Toxic Unit, Heavy metal

  15. Evaluation of AQUI-S(TM) (efficacy and minimum toxic concentration) as a fish anaesthetic/sedative for public aquaculture in the United States

    USGS Publications Warehouse

    Stehly, G.R.; Gingerich, W.H.

    1999-01-01

    A preliminary evaluation of efficacy and minimum toxic concentration of AQUI-S(TM), a fish anaesthetic/sedative, was determined in two size classes of six species of fish important to US public aquaculture (bluegill, channel catfish, lake trout, rainbow trout, walleye and yellow perch). In addition, efficacy and minimum toxic concentration were determined in juvenile-young adult (fish aged 1 year or older) rainbow trout acclimated to water at 7 ??C, 12 ??C and 17 ??C. Testing concentrations were based on determinations made with range-finding studies for both efficacy and minimum toxic concentration. Most of the tested juvenile-young adult fish species were induced in 3 min or less at a nominal AQUI-S(TM) concentration of 20 mg L-1. In juvenile-young adult fish, the minimum toxic concentration was at least 2.5 times the selected efficacious concentration. Three out of five species of fry-fingerlings (1.25-12.5 cm in length and < 1 year old) were induced in ??? 4.1 min at a nominal concentration of 20 mg L-1 AQUI-S(TM), with the other two species requiring nominal concentrations of 25 and 35 mg L-1 for similar times of induction. Recovery times were ??? 7.3 rain for all species in the two size classes. In fry-fingerlings, the minimum toxic concentration was at least 1.4 times the selected efficacious concentration. There appeared to be little relationship between size of fish and concentrations or times to induction, recovery times and minimum toxic concentration. The times required for induction and for recovery were increased in rainbow trout as the acclimation temperature was reduced.

  16. Is the Factor-of-2 Rule Broadly Applicable for Evaluating the Prediction Accuracy of Metal-Toxicity Models?

    PubMed

    Meyer, Joseph S; Traudt, Elizabeth M; Ranville, James F

    2018-01-01

    In aquatic toxicology, a toxicity-prediction model is generally deemed acceptable if its predicted median lethal concentrations (LC50 values) or median effect concentrations (EC50 values) are within a factor of 2 of their paired, observed LC50 or EC50 values. However, that rule of thumb is based on results from only two studies: multiple LC50 values for the fathead minnow (Pimephales promelas) exposed to Cu in one type of exposure water, and multiple EC50 values for Daphnia magna exposed to Zn in another type of exposure water. We tested whether the factor-of-2 rule of thumb also is supported in a different dataset in which D. magna were exposed separately to Cd, Cu, Ni, or Zn. Overall, the factor-of-2 rule of thumb appeared to be a good guide to evaluating the acceptability of a toxicity model's underprediction or overprediction of observed LC50 or EC50 values in these acute toxicity tests.

  17. Amelioration of boron toxicity in sweet pepper as affected by calcium management under an elevated CO2 concentration.

    PubMed

    Piñero, María Carmen; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2017-04-01

    We investigated B tolerance in sweet pepper plants (Capsicum annuun L.) under an elevated CO 2 concentration, combined with the application of calcium as a nutrient management amelioration technique. The data show that high B affected the roots more than the aerial parts, since there was an increase in the shoot/root ratio, when plants were grown with high B levels; however, the impact was lessened when the plants were grown at elevated CO 2 , since the root FW reduction caused by excess B was less marked at the high CO 2 concentration (30.9% less). Additionally, the high B concentration affected the membrane permeability of roots, which increased from 39 to 54% at ambient CO 2 concentration, and from 38 to 51% at elevated CO 2 concentration, producing a cation imbalance in plants, which was differentially affected by the CO 2 supply. The Ca surplus in the nutrient solution reduced the nutritional imbalance in sweet pepper plants produced by the high B concentration, at both CO 2 concentrations. The medium B concentration treatment (toxic according to the literature) did not result in any toxic effect. Hence, there is a need to review the literature on critical and toxic B levels taking into account increases in atmospheric CO 2 .

  18. Automated Test Systems for Toxic Vapor Detectors

    NASA Technical Reports Server (NTRS)

    Mattson, C. B.; Hammond, T. A.; Schwindt, C. J.

    1997-01-01

    The NASA Toxic Vapor Detection Laboratory (TVDL) at the Kennedy Space Center (KSC), Florida, has been using Personal Computer based Data Acquisition and Control Systems (PCDAS) for about nine years. These systems control the generation of toxic vapors of known concentrations under controlled conditions of temperature and humidity. The PCDAS also logs the test conditions and the test article responses in data files for analysis by standard spreadsheets or custom programs. The PCDAS was originally developed to perform standardized qualification and acceptance tests in a search for a commercial off-the-shelf (COTS) toxic vapor detector to replace the hydrazine detectors for the Space Shuttle launch pad. It has since become standard test equipment for the TVDL and is indispensable in producing calibration standards for the new hydrazine monitors at the 10 part per billion (ppb) level. The standard TVDL PCDAS can control two toxic vapor generators (TVG's) with three channels each and two flow/ temperature / humidity (FTH) controllers and it can record data from up to six toxic vapor detectors (TVD's) under test and can deliver flows from 5 to 50 liters per minute (L/m) at temperatures from near zero to 50 degrees Celsius (C) using an environmental chamber to maintain the sample temperature. The concentration range for toxic vapors depends on the permeation source installed in the TVG. The PCDAS can provide closed loop control of temperature and humidity to two sample vessels, typically one for zero gas and one for the standard gas. This is required at very low toxic vapor concentrations to minimize the time required to passivate the sample delivery system. Recently, there have been several requests for information about the PCDAS by other laboratories with similar needs, both on and off KSC. The purpose of this paper is to inform the toxic vapor detection community of the current status and planned upgrades to the automated testing of toxic vapor detectors at the

  19. Automated Test Systems for Toxic Vapor Detectors

    NASA Technical Reports Server (NTRS)

    Mattson, C. B.; Hammond, T. A.; Schwindt, C. J.

    1997-01-01

    The NASA Toxic Vapor Detection Laboratory (TVDL) at the Kennedy Space Center (KSC), Florida, has been using Personal Computer based Data Acquisition and Control Systems (PCDAS) for about nine years. These systems control the generation of toxic vapors of known concentrations under controlled conditions of temperature and humidity. The PCDAS also logs the test conditions and the test article responses in data files for analysis by standard spreadsheets or custom programs. The PCDAS was originally developed to perform standardized qualification and acceptance tests in a search for a commercial off-the-shelf (COTS) toxic vapor detector to replace the hydrazine detectors for the Space Shuttle launch pad. It has since become standard test equipment for the TVDL and is indispensable in producing calibration standards for the new hydrazine monitors at the 10 part per billion (ppb) level. The standard TVDL PCDAS can control two toxic vapor generators (TVG's) with three channels each and two flow/temperature/humidity (FIFH) controllers and it can record data from up to six toxic vapor detectors (TVD's) under test and can deliver flows from 5 to 50 liters per minute (L/m) at temperatures from near zero to 50 degrees Celsius (C) using an environmental chamber to maintain the sample temperature. The concentration range for toxic vapors depends on the permeation source installed in the TVG. The PCDAS can provide closed loop control of temperature and humidity to two sample vessels, typically one for zero gas and one for the standard gas. This is required at very low toxic vapor concentrations to minimize the time required to passivate the sample delivery system. Recently, there have been several requests for information about the PCDAS by other laboratories with similar needs, both on and off KSC. The purpose of this paper is to inform the toxic vapor detection community of the current status and planned upgrades to the automated testing of toxic vapor detectors at the Kennedy

  20. The toxic effect of different concentrations of povidone iodine on the rabbit's cornea.

    PubMed

    Jiang, Jin; Wu, Miaoqin; Shen, Ting

    2009-01-01

    To investigate the effects of polyvinylpyrrolidone (i.e., povidone) iodine (PVP-I) in different concentrations on the rabbit's cornea. PVP-I in various concentrations was instilled into the conjunctival sac and injected into the anterior chamber independently. The toxicity to the cornea was assessed by fluorescence dye, specular microscopy, and corneal pachymetry. After conjunctival sac PVP-I instillation, severe epithelial damage was observed at the concentrations of 5.0% and 2.5%. After anterior chamber PVP-I injection, significant corneal edema was observed at the concentrations of 2.0% and 1.5%. It can be safe and feasible to use 0.5% or 1.0% concentrations of PVP-I in conjunctival sac instillation for preoperative antisepsis.

  1. Protectiveness of species sensitivity distribution hazard concentrations for acute toxicity used in endangered species risk assessment.

    PubMed

    Raimondo, Sandy; Vivian, Deborah N; Delos, Charles; Barron, Mace G

    2008-12-01

    A primary objective of threatened and endangered species conservation is to ensure that chemical contaminants and other stressors do not adversely affect listed species. Assessments of the ecological risks of chemical exposures to listed species often rely on the use of surrogate species, safety factors, and species sensitivity distributions (SSDs) of chemical toxicity; however, the protectiveness of these approaches can be uncertain. We comprehensively evaluated the protectiveness of SSD first and fifth percentile hazard concentrations (HC1, HC5) relative to the application of safety factors using 68 SSDs generated from 1,482 acute (lethal concentration of 50%, or LC50) toxicity records for 291 species, including 24 endangered species (20 fish, four mussels). The SSD HC5s and HCls were lower than 97 and 99.5% of all endangered species mean acute LC50s, respectively. The HC5s were significantly less than the concentrations derived from applying safety factors of 5 and 10 to rainbow trout (Oncorhynchus mykiss) toxicity data, and the HCls were generally lower than the concentrations derived from a safety factor of 100 applied to rainbow trout toxicity values. Comparison of relative sensitivity (SSD percentiles) of broad taxonomic groups showed that crustaceans were generally the most sensitive taxa and taxa sensitivity was related to chemical mechanism of action. Comparison of relative sensitivity of narrow fish taxonomic groups showed that standard test fish species were generally less sensitive than salmonids and listed fish. We recommend the use of SSDs as a distribution-based risk assessment approach that is generally protective of listed species.

  2. Toxic plasma concentration of ropivacaine after a paravertebral block in a patient suffering from severe hypoalbuminemia.

    PubMed

    Calenda, Emile; Baste, Jean Marc; Hajjej, Ridha; Danielou, Eric; Peillon, Christophe

    2014-03-01

    A case of systemic ropivacaine toxicity from a continuous thoracic paravertebral block in an adult patient who received a lobectomy is presented. The catheter was placed by the surgeon. Eleven hours after the start of the infusion, the patient experienced an arrhythmia leading to death. The total venous plasma concentration of ropivacaine was high (3.2 μg/mL). Furthermore, the patient had severe hypoalbuminemia (albumin 24 g/L), which resulted in the increase of the unbound ropivacaine plasma concentration that was responsible for the toxic side effects. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Acute Toxicity of Ternary Cd-Cu-Ni and Cd-Ni-Zn Mixtures to Daphnia magna: Dominant Metal Pairs Change along a Concentration Gradient.

    PubMed

    Traudt, Elizabeth M; Ranville, James F; Meyer, Joseph S

    2017-04-18

    Multiple metals are usually present in surface waters, sometimes leading to toxicity that currently is difficult to predict due to potentially non-additive mixture toxicity. Previous toxicity tests with Daphnia magna exposed to binary mixtures of Ni combined with Cd, Cu, or Zn demonstrated that Ni and Zn strongly protect against Cd toxicity, but Cu-Ni toxicity is more than additive, and Ni-Zn toxicity is slightly less than additive. To consider multiple metal-metal interactions, we exposed D. magna neonates to Cd, Cu, Ni, or Zn alone and in ternary Cd-Cu-Ni and Cd-Ni-Zn combinations in standard 48 h lethality tests. In these ternary mixtures, two metals were held constant, while the third metal was varied through a series that ranged from nonlethal to lethal concentrations. In Cd-Cu-Ni mixtures, the toxicity was less than additive, additive, or more than additive, depending on the concentration (or ion activity) of the varied metal and the additivity model (concentration-addition or independent-action) used to predict toxicity. In Cd-Ni-Zn mixtures, the toxicity was less than additive or approximately additive, depending on the concentration (or ion activity) of the varied metal but independent of the additivity model. These results demonstrate that complex interactions of potentially competing toxicity-controlling mechanisms can occur in ternary-metal mixtures but might be predicted by mechanistic bioavailability-based toxicity models.

  4. Single oral dose toxicity test of blue honeysuckle concentrate in mice.

    PubMed

    Kim, Hyung-Soo; Park, Sang-In; Choi, Seung-Hoon; Song, Chang-Hyun; Park, Soo-Jin; Shin, Yong-Kook; Han, Chang-Hyun; Lee, Young Joon; Ku, Sae-Kwang

    2015-03-01

    The objective of this study was to obtain single oral dose toxicity information for concentrated and lyophilized powder of blue honeysuckle (Lonicera caerulea L., Caprifoliaceae; BHcL) in female and male ICR mice to aid in the process of developing natural origin medicinal ingredients or foods following proximate analysis and phytochemical profile measurement. The proximate analysis revealed that BHcL had an energy value of 3.80 kcal/g and contained 0.93 g/g of carbohydrate, 0.41 g/g of sugar, 0.02 g/g of protein, and 0.20 mg/g of sodium. BHcL did not contain lipids, including saturated lipids, trans fats, or cholesterols. Further, BHcL contained 4.54% of betaine, 210.63 mg/g of total phenols, 159.30 mg/g of total flavonoids, and 133.57 mg/g of total anthocyanins. Following administration of a single oral BHcL treatment, there were no treatment-related mortalities, changes in body weight (bw) or organ weight, clinical signs, necropsy or histopathological findings up to 2,000 mg/kg bw, the limited dosage for rodents of both sexes. We concluded that BHcL is a practically non-toxic material in toxicity potency.

  5. Single Oral Dose Toxicity Test of Blue Honeysuckle Concentrate in Mice

    PubMed Central

    Park, Sang-In; Choi, Seung-Hoon; Song, Chang-Hyun; Park, Soo-Jin; Shin, Yong-Kook; Han, Chang-Hyun; Lee, Young Joon; Ku, Sae-Kwang

    2015-01-01

    The objective of this study was to obtain single oral dose toxicity information for concentrated and lyophilized powder of blue honeysuckle (Lonicera caerulea L., Caprifoliaceae; BHcL) in female and male ICR mice to aid in the process of developing natural origin medicinal ingredients or foods following proximate analysis and phytochemical profile measurement. The proximate analysis revealed that BHcL had an energy value of 3.80 kcal/g and contained 0.93 g/g of carbohydrate, 0.41 g/g of sugar, 0.02 g/g of protein, and 0.20 mg/g of sodium. BHcL did not contain lipids, including saturated lipids, trans fats, or cholesterols. Further, BHcL contained 4.54% of betaine, 210.63 mg/g of total phenols, 159.30 mg/g of total flavonoids, and 133.57 mg/g of total anthocyanins. Following administration of a single oral BHcL treatment, there were no treatment-related mortalities, changes in body weight (bw) or organ weight, clinical signs, necropsy or histopathological findings up to 2,000 mg/kg bw, the limited dosage for rodents of both sexes. We concluded that BHcL is a practically non-toxic material in toxicity potency. PMID:25874034

  6. A METHOD OF ASSESSING AIR TOXICS CONCENTRATIONS IN URBAN AREAS USING MOBILE PLATFORM MEASUREMENTS

    EPA Science Inventory

    The objective of this paper is to demonstrate an approach to characterize the spatial variability in ambient air concentrations using mobile platform measurements. This approach may be useful for air toxic assessments in Environmental Justice applications, epidemiological studies...

  7. Effects of calcium at toxic concentrations of cadmium in plants.

    PubMed

    Huang, Danlian; Gong, Xiaomin; Liu, Yunguo; Zeng, Guangming; Lai, Cui; Bashir, Hassan; Zhou, Lu; Wang, Dafei; Xu, Piao; Cheng, Min; Wan, Jia

    2017-05-01

    This review provides new insight that calcium plays important roles in plant growth, heavy metal accumulation and translocation, photosynthesis, oxidative damage and signal transduction under cadmium stress. Increasing heavy metal pollution problems have raised word-wide concerns. Cadmium (Cd), being a highly toxic metal, poses potential risks both to ecosystems and human health. Compared with conventional technologies, phytoremediation, being cost-efficient, highly stable and environment-friendly, is believed to be a promising green technology for Cd decontamination. However, Cd can be easily taken up by plants and may cause severe phytotoxicity to plants, thus limiting the efficiency of phytoremediation. Various researches are being done to investigate the effects of exogenous substances on the mitigation of Cd toxicity to plants. Calcium (Ca) is an essential plant macronutrient that involved in various plant physiological processes, such as plant growth and development, cell division, cytoplasmic streaming, photosynthesis and intracellular signaling transduction. Due to the chemical similarity between Ca and Cd, Ca may mediate Cd-induced physiological or metabolic changes in plants. Recent studies have shown that Ca could be used as an exogenous substance to protect plants against Cd stress by the alleviation of growth inhibition, regulation of metal uptake and translocation, improvement of photosynthesis, mitigation of oxidative damages and the control of signal transduction in the plants. The effects of Ca on toxic concentrations of Cd in plants are reviewed. This review also provides new insight that plants with enhanced Ca level have improved resistance to Cd stress.

  8. Molecular Control of TiO2-NPs Toxicity Formation at Predicted Environmental Relevant Concentrations by Mn-SODs Proteins

    PubMed Central

    Wu, Qiuli; Li, Yiping; Tang, Meng; Ye, Boping; Wang, Dayong

    2012-01-01

    With growing concerns of the safety of nanotechnology, the in vivo toxicity of nanoparticles (NPs) at environmental relevant concentrations has drawn increasing attentions. We investigated the possible molecular mechanisms of titanium nanoparticles (Ti-NPs) in the induction of toxicity at predicted environmental relevant concentrations. In nematodes, small sizes (4 nm and 10 nm) of TiO2-NPs induced more severe toxicities than large sizes (60 nm and 90 nm) of TiO2-NPs on animals using lethality, growth, reproduction, locomotion behavior, intestinal autofluorescence, and reactive oxygen species (ROS) production as endpoints. Locomotion behaviors could be significantly decreased by exposure to 4-nm and 10-nm TiO2-NPs at concentration of 1 ng/L in nematodes. Among genes required for the control of oxidative stress, only the expression patterns of sod-2 and sod-3 genes encoding Mn-SODs in animals exposed to small sizes of TiO2-NPs were significantly different from those in animals exposed to large sizes of TiO2-NPs. sod-2 and sod-3 gene expressions were closely correlated with lethality, growth, reproduction, locomotion behavior, intestinal autofluorescence, and ROS production in TiO2-NPs-exposed animals. Ectopically expression of human and nematode Mn-SODs genes effectively prevented the induction of ROS production and the development of toxicity of TiO2-NPs. Therefore, the altered expression patterns of Mn-SODs may explain the toxicity formation for different sizes of TiO2-NPs at predicted environmental relevant concentrations. In addition, we demonstrated here a strategy to investigate the toxicological effects of exposure to NPs upon humans by generating transgenic strains in nematodes for specific human genes. PMID:22973466

  9. Toxicity of environmentally realistic concentrations of chlorpyrifos and terbuthylazine in indoor microcosms.

    PubMed

    Pereira, Ana Santos; Cerejeira, Maria José; Daam, Michiel A

    2017-09-01

    Few studies have been conducted into the evaluation of environmentally realistic pesticide mixtures using model ecosystems. In the present study, the effects of single and combined environmentally realistic concentrations of the herbicide terbuthylazine and the insecticide chlorpyrifos were evaluated using laboratory microcosms. Direct toxic effects of chlorpyrifos were noted on copepod nauplii and cladocerans and the recovery of the latter was likely related with the decrease observed in rotifer abundances. Terbuthylazine potentiated the effect of chlorpyrifos on feeding rates of Daphnia magna, presumably by triggering the transformation of chlorpyrifos to more toxic oxon-analogs. Possible food-web interactions resulting from multiple chemical (and other) stressors likely to be present in edge-of-field water bodies need to be further evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Effect of diet quality on chronic toxicity of aqueous lead to the amphipod Hyalella azteca

    USGS Publications Warehouse

    Besser, John M.; Ivey, Chris D.; Brumbaugh, William G.; Ingersoll, Christopher G.

    2016-01-01

    The authors investigated the chronic toxicity of aqueous Pb to the amphipod Hyalella azteca (Hyalella) in 42-d tests using 2 different diets: 1) the yeastþcereal leafþtrout pellet (YCT) diet, fed at the uniform low ration used in standard methods for sediment toxicity tests; and 2) a new diet of diatomsþTetraMin flakes (DT), fed at increasing rations over time, that has been optimized for use in Hyalella water-only tests. Test endpoints included survival, weight, biomass, fecundity, and total young. Lethal effects of Pb were similar for the DT and YCT tests (20% lethal concentration [LC20]¼13 mg/L and 15mg/L, respectively, as filterable Pb). In contrast, weight and fecundity endpoints were not significantly affected in the DT test at Pb concentrations up to 63 mg/L, but these endpoints were significantly reduced by Pb in the YCT test—and in a 2005 test in the same laboratory with a diet of conditioned Rabbit Chow (RC-2005). The fecundity and total young endpoints from the YCT and RC-2005 tests were considered unreliable because fecundity in controls did not meet test acceptability criteria, but both of these tests still produced lower Pb effect concentrations (for weight or biomass) than the test with the DT diet. The lowest biotic ligand model–normalized effect concentrations for the 3 tests ranged from 3.7mg/L (weight 20% effect concentration [EC20] for the RC-2005 test) to 8.2 mg/L (total young EC20 for the DT test), values that would rank Hyalella as the second or third most sensitive of 13 genera in a species sensitivity distribution for chronic Pb toxicity. These results demonstrate that toxicity tests with Hyalella fed optimal diets can meet more stringent test acceptability criteria for control performance, but suggest that results of these tests may underestimate sublethal toxic effects of Pb to Hyalella under suboptimal feeding regimes.

  11. Determination of toxic metals in drinking water sources in the Chief Albert Luthuli Local Municipality in Mpumalanga, South Africa

    NASA Astrophysics Data System (ADS)

    Nthunya, Lebea N.; Masheane, Monaheng L.; Malinga, Soraya P.; Nxumalo, Edward N.; Mamba, Bhekie B.; Mhlanga, Sabelo D.

    2017-08-01

    This study was conducted to determine the presence and levels of toxic metals on selected water sources in a rural community in Lochiel, South Africa. Collection of water samples from identified drinking water sources (open wells, community tanks, water treatment works and boreholes) was done in all seasons of the year (winter, spring, summer and autumn) between 2014 and 2015. The concentrations of identified toxic metals (cobalt, chromium, copper, lead, zinc, manganese and iron) were measured using ICP-OES. Some water sources were found to contain concentrations of toxic metals at levels slightly higher than USEPA, WHO and SANS241 set limits (e.g. manganese and cobalt), while others were found to be within the acceptable limits. This suggested that the residents residing in locations that have water sources containing toxic metals at the concentrations above the set limits are at risk and susceptible to suffer diseases caused by these toxic metals. The side effects of the metals may not be acute; however prolonged exposure to the toxic metals may result in detrimental effects since they are known to bioaccumulate in the body.

  12. Toxicity of Monoterpene Structure, Diversity and Concentration to Mountain Pine Beetles, Dendroctonus ponderosae: Beetle Traits Matter More.

    PubMed

    Reid, Mary L; Sekhon, Jagdeep K; LaFramboise, Lanielle M

    2017-04-01

    A high diversity of plant defenses may be a response to herbivore diversity or may be collectively more toxic than single compounds, either of which may be important for understanding insect-plant associations. Monoterpenes in conifers are particularly diverse. We tested the fumigant toxicity of four monoterpenes, alone and in combination, to mountain pine beetles, Dendroctonus ponderosae, in the context of the beetles' individual body traits. Chemical structures of tested monoterpene hydrocarbons had modest effects on beetle survival, mass loss, water content and fat content, with (R)-(+)-limonene tending to be more toxic than (-)-α-pinene, (-)-β-pinene, and (+)-3-carene. Monoterpene diversity (all qualitative combinations of one to four monoterpenes) did not affect toxicity. Concentration (0 to 1200 ppm) of individual monoterpenes was a strong determinant of toxicity. Beetle body size and body condition index strongly and positively affected survival during monoterpene treatments. Larger beetles in better condition lost proportionally less mass during exposure, where proportion mass loss negatively affected survivorship. Toxicity was much more associated with water loss than with fat loss, suggesting that a main cost of detoxification is excretion, a process that has received little attention. These results provide insight into the determinants of beetle success in historic and novel hosts that differ in monoterpene composition and concentration. We also suggest that water availability will affect beetle success directly through their ability to tolerate detoxification as well as indirectly through host responses to drought.

  13. Shelf Life Extension of Tomato Paste Through Organoleptically Acceptable Concentration of Betel Leaf Essential Oil Under Accelerated Storage Environment.

    PubMed

    Basak, Suradeep

    2018-05-01

    This study was attempted with two objectives: (1) to find an acceptable concentration of betel leaf essential oil (BLEO) based on sensory evaluation that can be employed in tomato paste; (2) to evaluate the effect of the acceptable concentration of BLEO in the paste during accelerated storage under 89 ± 1.2% RH at 39 ± 1 °C. Linguistic data obtained from sensory evaluation of tomato paste treated with 4 different concentrations of BLEO were analyzed using fuzzy logic approach. The organoleptically acceptable concentration was determined to be 0.25 mg/g of BLEO in tomato paste. The effect of the selected concentration of BLEO on different physicochemical and microbial attributes of tomato paste during accelerated storage was studied. Untreated tomato paste was found to have 12% less total antioxidant capacity than treated paste at the end of storage. Based on a * /b * value in CIELAB color space, the BLEO treated paste efficiently extended the shelf life by 14 days with respect to untreated paste samples under accelerated storage conditions. BLEO comes with a tag contributing to green consumerism, and its application as food preservative is no less than a value addition to the product. Essential oil is considered to have promising potential as an alternative food preservative, and its use is practically possible if they could overcome the sensory barrier, while retaining the preservative potency. The importance of identifying the sensory attributes for commercial success of essential oil treated food product was considered in this study. It contributes to the potency of organoleptically acceptable concentration of BLEO in shelf life extension of tomato paste under accelerated storage conditions. At industrial level, the estimated shelf life of treated tomato paste can be increased by incorporating more hurdles alongside BLEO. © 2018 Institute of Food Technologists®.

  14. Determination and validation of an aquatic Maximum Acceptable Concentration-Environmental Quality Standard (MAC-EQS) value for the agricultural fungicide azoxystrobin.

    PubMed

    Rodrigues, Elsa Teresa; Pardal, Miguel Ângelo; Gante, Cristiano; Loureiro, João; Lopes, Isabel

    2017-02-01

    The main goal of the present study was to determine and validate an aquatic Maximum Acceptable Concentration-Environmental Quality Standard (MAC-EQS) value for the agricultural fungicide azoxystrobin (AZX). Assessment factors were applied to short-term toxicity data using the lowest EC 50 and after the Species Sensitivity Distribution (SSD) method. Both ways of EQS generation were applied to a freshwater toxicity dataset for AZX based on available data, and to marine toxicity datasets for AZX and Ortiva ® (a commercial formulation of AZX) obtained by the present study. A high interspecific variability in AZX sensitivity was observed in all datasets, being the copepoda Eudiaptomus graciloides (LC 50,48h  = 38 μg L -1 ) and the gastropod Gibbula umbilicalis (LC 50,96h  = 13 μg L -1 ) the most sensitive freshwater and marine species, respectively. MAC-EQS values derived using the lowest EC 50 (≤0.38 μg L -1 ) were more protective than those derived using the SSD method (≤3.2 μg L -1 ). After comparing the MAC-EQS values estimated in the present study to the smallest AA-EQS available, which protect against the occurrence of prolonged exposure of AZX, the MAC-EQS values derived using the lowest EC 50 were considered overprotective and a MAC-EQS of 1.8 μg L -1 was validated and recommended for AZX for the water column. This value was derived from marine toxicity data, which highlights the importance of testing marine organisms. Moreover, Ortiva affects the most sensitive marine species to a greater extent than AZX, and marine species are more sensitive than freshwater species to AZX. A risk characterization ratio higher than one allowed to conclude that AZX might pose a high risk to the aquatic environment. Also, in a wider conclusion, before new pesticides are approved, we suggest to improve the Tier 1 prospective Ecological Risk Assessment by increasing the number of short-term data, and apply the SSD approach, in order to ensure the safety of

  15. Effects of calcium, magnesium, and sodium on alleviating cadmium toxicity to Hyalella azteca

    USGS Publications Warehouse

    Jackson, B.P.; Lasier, P.J.; Miller, W.P.; Winger, P.V.

    2000-01-01

    Toxicity of trace metal ions to aquatic organisms, arising through either anthropogenic inputs or acidification of surface waters, continues to be both a regulatory and environmental problem. It is generally accepted that the free metal ion is the major toxic species (Florence et a1.,1992) and that inorganic or organic complexation renders the metal ion non-bioavailable (Meador, 1991, Galvez and Wood, 1997). However, water chemistry parameters such as alkalinity, hardness, dissolved organic carbon and pH influence metal ion toxicity either directly by lowering free metal ion concentration or indirectly through synergistic or antagonistic effects. Alkalinity and salinity can affect the speciation of metal ions by increasing ion-pair formation, thus decreasing free metal ion concentration. For example, Cu was found to be less toxic to rainbow trout in waters of high alkalinity (Miller and Mackay, 1980), due to formation of CuCO3 ion pair, and corresponding reduction in free Cu2+ concentration. The influence of salinity on the toxicity of cadmium to various organisms has been demonstrated in a number of studies (Bervoets et al., 1995, Hall et al., 1995, Lin and Dunson, 1993, Blust et al., 1992). In all these studies the apparent toxicity of cadmium was lowered as salinity was increased due to increased formation of CdC1+ and CDCl2 aqueous complexes that are non-toxic or of much lower toxicity than the free Cd2+ ion. Changes in pH exert both a biological and chemical effect on metal ion toxicity (Campbell and Stokes, 1985). Low pH favors greater metal ion solubility, and, in the absence of complexing ions, reduced speciation of the metal ion, which tends to increase toxicity compared to higher pH. However, Iow pH also enhances competition between H+ and metal ion for cell surface binding sites, which tends to decrease metal ion toxicity.

  16. Spacecraft Minimum Allowable Concentrations: Determination, Application, and Contingency Situations

    NASA Technical Reports Server (NTRS)

    Marshburn, Thomas H.; Dawson, David L. (Technical Monitor)

    1999-01-01

    This document is an outline of a presentation about the determination of minimum allowable concentrations in spacecraft. The presentation reviews the type of toxins and mechanisms to determine the acceptable concentrations of these toxic substances. The considerations for the unique situation that spaceflight entails including zero gravity, and the intense scrutiny are reviewed. The current measurement hardware is reviewed. The spacecraft atmospheres on the Shuttle, airflow, the Space Station and the EMU in respect to airflow, pressure, constituents are also summarized. Contingency situations and potential hazards are also discussed.

  17. Preschool children's taste acceptance of highly concentrated fluoride compounds: effects on nonverbal behavior.

    PubMed

    Kolb, Anne-Kathrin; Schmied, Kirsten; Fassheber, Peter; Heinrich-Weltzien, Roswitha

    2013-01-01

    The aim of this video-based study was to examine the taste acceptance of children between the ages of 2 and 5 years regarding highly concentrated fluoride preparations in kindergarten-based preventive programs. The fluoride preparation Duraphat was applied to 16 children, Elmex fluid to 15 children, and Fluoridin N5 to 14 children. The procedure was conducted according to a standardized protocol and videotaped Three raters evaluated the children's nonverbal behavior as a measure of taste acceptance on the Frankl Behavior Rating Scale. The interrater reliability (intraclass correlation coefficient; ICC) was .86. In an interview, children indicated the taste of the fluoride preparations on a three-point "smiley" rating scale. The interviewer used a hand puppet during the survey to establish confidence between the children and examiners. Children's nonverbal behavior was significantly more positive after Fluoridin N5 and Duraphat were applied compared to the application of Elmex fluid. The same trend was found during the smiley assessment. The response of children who displayed cooperative positive behavior before the application of fluoride preparations was significantly more positive than those who displayed uncooperative negative behavior. To achieve a high acceptance of the application of fluoride preparations among preschool children, flavorful preparations should be used.

  18. [Potentially toxic antibiotics concentrations after administration using impregnated dressing in a severe burned patient: A case report].

    PubMed

    Dupouey, Julien; Wiramus, Sandrine; Albanese, Jacques; Guilhaumou, Romain; Blin, Olivier

    2016-10-01

    Severe burned patients present high risk of skins infections, frequently due to Pseudomonas aeruginosa. Impregnated dressings with amikacin or colistin could be a good alternative to obtain effective concentration directly at the infected site. Therapeutic drug monitoring for these antibiotics is currently recommended after an intravenous administration to obtain effective and non-toxic plasmatic concentrations. However, data are lacking about systemic exposition and risk of toxicity after an administration with impregnated dressings. We report the case of a severe burned patient with cutaneous infection treated with amikacin and colistin impregnated dressings, for which plasmatic pharmacokinetic profiles were performed. Copyright © 2016 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

  19. Pyrethroid insecticide concentrations and toxicity in streambed sediments and loads in surface waters of the San Joaquin Valley, California, USA

    USGS Publications Warehouse

    Domagalski, Joseph L.; Weston, Donald P.; Zhang, Minghua; Hladik, Michelle L.

    2010-01-01

    Pyrethroid insecticide use in California, USA, is growing, and there is a need to understand the fate of these compounds in the environment. Concentrations and toxicity were assessed in streambed sediment of the San Joaquin Valley of California, one of the most productive agricultural regions of the United States. Concentrations were also measured in the suspended sediment associated with irrigation or storm‐water runoff, and mass loads during storms were calculated. Western valley streambed sediments were frequently toxic to the amphipod, Hyalella azteca, with most of the toxicity attributable to bifenthrin and cyhalothrin. Up to 100% mortality was observed in some locations with concentrations of some pyrethroids up to 20 ng/g. The western San Joaquin Valley streams are mostly small watersheds with clay soils, and sediment‐laden irrigation runoff transports pyrethroid insecticides throughout the growing season. In contrast, eastern tributaries and the San Joaquin River had low bed sediment concentrations (<1 ng/g) and little or no toxicity because of the preponderance of sandy soils and sediments. Bifenthrin, cyhalothrin, and permethrin were the most frequently detected pyrethroids in irrigation and storm water runoff. Esfenvalerate, fenpropathrin, and resmethrin were also detected. All sampled streams contributed to the insecticide load of the San Joaquin River during storms, but some compounds detected in the smaller creeks were not detected in the San Joaquin River. The two smallest streams, Ingram and Hospital Creeks, which had high sediment toxicity during the irrigation season, accounted for less than 5% of the total discharge of the San Joaquin River during storm conditions, and as a result their contribution to the pyrethroid mass load of the larger river was minimal. 

  20. Assessing time-integrated dissolved concentrations and predicting toxicity of metals during diel cycling in streams

    USGS Publications Warehouse

    Balistrieri, Laurie S.; Nimick, David A.; Mebane, Christopher A.

    2012-01-01

    Evaluating water quality and the health of aquatic organisms is challenging in systems with systematic diel (24 hour) or less predictable runoff-induced changes in water composition. To advance our understanding of how to evaluate environmental health in these dynamic systems, field studies of diel cycling were conducted in two streams (Silver Bow Creek and High Ore Creek) affected by historical mining activities in southwestern Montana. A combination of sampling and modeling tools were used to assess the toxicity of metals in these systems. Diffusive Gradients in Thin Films (DGT) samplers were deployed at multiple time intervals during diel sampling to confirm that DGT integrates time-varying concentrations of dissolved metals. Thermodynamic speciation calculations using site specific water compositions, including time-integrated dissolved metal concentrations determined from DGT, and a competitive, multiple-metal biotic ligand model incorporated into the Windemere Humic Aqueous Model Version 6.0 (WHAM VI) were used to determine the chemical speciation of dissolved metals and biotic ligands. The model results were combined with previously collected toxicity data on cutthroat trout to derive a relationship that predicts the relative survivability of these fish at a given site. This integrative approach may prove useful for assessing water quality and toxicity of metals to aquatic organisms in dynamic systems and evaluating whether potential changes in environmental health of aquatic systems are due to anthropogenic activities or natural variability.

  1. Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

    USGS Publications Warehouse

    Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.

    1998-01-01

    Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. We investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by ???70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

  2. Influence of potentially confounding factors on sea urchin porewater toxicity tests

    USGS Publications Warehouse

    Carr, R.S.; Biedenbach, J.M.; Nipper, M.

    2006-01-01

    The influence of potentially confounding factors has been identified as a concern for interpreting sea urchin porewater toxicity test data. The results from >40 sediment-quality assessment surveys using early-life stages of the sea urchin Arbacia punctulata were compiled and examined to determine acceptable ranges of natural variables such as pH, ammonia, and dissolved organic carbon on the fertilization and embryological development endpoints. In addition, laboratory experiments were also conducted with A. punctulata and compared with information from the literature. Pore water with pH as low as 6.9 is an unlikely contributor to toxicity for the fertilization and embryological development tests with A. punctulata. Other species of sea urchin have narrower pH tolerance ranges. Ammonia is rarely a contributing factor in pore water toxicity tests using the fertilization endpoint, but the embryological development endpoint may be influenced by ammonia concentrations commonly found in porewater samples. Therefore, ammonia needs to be considered when interpreting results for the embryological development test. Humic acid does not affect sea urchin fertilization at saturation concentrations, but it could have an effect on the embryological development endpoint at near-saturation concentrations. There was no correlation between sediment total organic carbon concentrations and porewater dissolved organic carbon concentrations. Because of the potential for many varying substances to activate parthenogenesis in sea urchin eggs, it is recommended that a no-sperm control be included with every fertilization test treatment. ?? 2006 Springer Science+Business Media, Inc.

  3. Assessing the toxic effects of DMSO on cord blood to determine exposure time limits and the optimum concentration for cryopreservation.

    PubMed

    Fry, L J; Querol, S; Gomez, S G; McArdle, S; Rees, R; Madrigal, J A

    2015-08-01

    Advantages of using cord blood (CB) over other sources of haematopoietic progenitor cells, such as bone marrow, include the ability to cryopreserve and bank the samples until requested for a transplant. Cryopreservation requires the addition of a cryoprotectant to prevent the formation of intracellular ice during freezing. Dimethyl sulphoxide (DMSO) is commonly used at a concentration of 10% (v/v); however, there is evidence to suggest this chemical is toxic to cells as well as to patients after infusion. The toxic effects of DMSO were assessed through cell viability and in vitro functional assays in fresh and post-thaw CB samples before determining the maximum exposure time and optimal concentration for cryopreservation. A dose-dependent toxicity of DMSO was observed in fresh samples with 40% removing all viable and functional haematopoietic progenitor cells (HPC). In fresh and post-thaw analysis, minimal toxic effect was observed when cryopreservation was delayed for up to 1 h after 10% DMSO addition. After thawing, DMSO washout was superior to dilution or unmanipulated when maintained for long periods (advantage observed 1 h after thawing). Finally, the optimum concentration for cryopreserving CB was found to be 7.5 to 10% with detrimental effects observed outside of this range. These results support the use of 7.5-10% as the optimal DMSO concentration and the maximum exposure time should be limited to <1 h prior to freezing and 30 min post-thaw. © 2015 International Society of Blood Transfusion.

  4. Mixture toxicity of wood preservative products in the fish embryo toxicity test.

    PubMed

    Coors, Anja; Dobrick, Jan; Möder, Monika; Kehrer, Anja

    2012-06-01

    Wood preservative products are used globally to protect wood from fungal decay and insects. We investigated the aquatic toxicity of five commercial wood preservative products, the biocidal active substances and some formulation additives contained therein, as well as six generic binary mixtures of the active substances in the fish embryo toxicity test (FET). Median lethal concentrations (LC50) of the single substances, the mixtures, and the products were estimated from concentration-response curves and corrected for concentrations measured in the test medium. The comparison of the experimentally observed mixture toxicity with the toxicity predicted by the concept of concentration addition (CA) showed less than twofold deviation for all binary mixtures of the active substances and for three of the biocidal products. A more than 60-fold underestimation of the toxicity of the fourth product by the CA prediction was detected and could be explained fully by the toxicity of one formulation additive, which had been labeled as a hazardous substance. The reason for the 4.6-fold underestimation of toxicity of the fifth product could not be explained unambiguously. Overall, the FET was found to be a suitable screening tool to verify whether the toxicity of formulated wood preservatives can reliably be predicted by CA. Applied as a quick and simple nonanimal screening test, the FET may support approaches of applying component-based mixture toxicity predictions within the environmental risk assessment of biocidal products, which is required according to European regulations. Copyright © 2012 SETAC.

  5. Concentration addition and independent action model: Which is better in predicting the toxicity for metal mixtures on zebrafish larvae.

    PubMed

    Gao, Yongfei; Feng, Jianfeng; Kang, Lili; Xu, Xin; Zhu, Lin

    2018-01-01

    The joint toxicity of chemical mixtures has emerged as a popular topic, particularly on the additive and potential synergistic actions of environmental mixtures. We investigated the 24h toxicity of Cu-Zn, Cu-Cd, and Cu-Pb and 96h toxicity of Cd-Pb binary mixtures on the survival of zebrafish larvae. Joint toxicity was predicted and compared using the concentration addition (CA) and independent action (IA) models with different assumptions in the toxic action mode in toxicodynamic processes through single and binary metal mixture tests. Results showed that the CA and IA models presented varying predictive abilities for different metal combinations. For the Cu-Cd and Cd-Pb mixtures, the CA model simulated the observed survival rates better than the IA model. By contrast, the IA model simulated the observed survival rates better than the CA model for the Cu-Zn and Cu-Pb mixtures. These findings revealed that the toxic action mode may depend on the combinations and concentrations of tested metal mixtures. Statistical analysis of the antagonistic or synergistic interactions indicated that synergistic interactions were observed for the Cu-Cd and Cu-Pb mixtures, non-interactions were observed for the Cd-Pb mixtures, and slight antagonistic interactions for the Cu-Zn mixtures. These results illustrated that the CA and IA models are consistent in specifying the interaction patterns of binary metal mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Sediment nickel bioavailability and toxicity to estuarine crustaceans of contrasting bioturbative behaviors--an evaluation of the SEM-AVS paradigm.

    PubMed

    Chandler, G Thomas; Schlekat, Christian E; Garman, Emily R; He, Lijian; Washburn, Katherine M; Stewart, Emily R; Ferry, John L

    2014-11-04

    Robust sediment quality criteria require chemistry and toxicity data predictive of concentrations where population/community response should occur under known geochemical conditions. Understanding kinetic and geochemical effects on toxicant bioavailability is key, and these are influenced by infaunal sediment bioturbation. This study used fine-scale sediment and porewater measurement of contrasting infaunal effects on carbon-normalized SEM-AVS to evaluate safe or potentially toxic nickel concentrations in a high-binding Spartina saltmarsh sediment (4%TOC; 35-45 μmol-S2-·g(-1)). Two crustaceans producing sharply contrasting bioturbation--the copepod Amphiascus tenuiremis and amphipod Leptocheirus plumulosus--were cultured in oxic to anoxic sediments with SEM[Ni]-AVS, TOC, porewater [Ni], and porewater DOC measured weekly. From 180 to 750 μg-Ni·g(-1) sediment, amphipod bioturbation reduced [AVS] and enhanced porewater [Ni]. Significant amphipod uptake, mortality, and growth-depression occurred at the higher sediment [Ni] even when [SEM-AVS]/foc suggested acceptable risk. Less bioturbative copepods produced higher AVS and porewater DOC but exhibited net population growth despite porewater [Ni] 1.3-1.7× their aqueous [Ni] LOEC. Copepod aqueous tests with/without dissolved organic matter showed significant aqueous DOC protection, which suggests porewater DOC attenuates sediment Ni toxicity. The SEM[Ni]-AVS relationship was predictive of acceptable risk for copepods at the important population-growth level.

  7. Prevalidation of the ex-vivo model PCLS for prediction of respiratory toxicity.

    PubMed

    Hess, A; Wang-Lauenstein, L; Braun, A; Kolle, S N; Landsiedel, R; Liebsch, M; Ma-Hock, L; Pirow, R; Schneider, X; Steinfath, M; Vogel, S; Martin, C; Sewald, K

    2016-04-01

    In acute inhalation toxicity studies, animals inhale substances at given concentrations. Without additional information, however, appropriate starting concentrations for in-vivo inhalation studies are difficult to estimate. The goal of this project was the prevalidation of precision-cut lung slices (PCLS) as an ex-vivo alternative to reduce the number of animals used in inhalation toxicity studies. According to internationally agreed principles for Prevalidation Studies, the project was conducted in three independent laboratories. The German BfR provided consultancy in validation principles and independent support with biostatistics. In all laboratories, rat PCLS were prepared and exposed to 5 concentrations of 20 industrial chemicals under submerged culture conditions for 1h. After 23 h post-incubation, toxicity was assessed by measurement of released lactate dehydrogenase and mitochondrial activity. In addition, protein content and pro-inflammatory cytokine IL-1α were measured. For all endpoints IC50 values were calculated if feasible. For each endpoint test acceptance criteria were established. This report provides the final results for all 20 chemicals. More than 900 concentration-response curves were analyzed. Log10[IC50 (μM)], obtained for all assay endpoints, showed best intra- and inter-laboratory consistency for the data obtained by WST-1 and BCA assays. While WST-1 and LDH indicated toxic effects for the majority of substances, only some of the substances induced an increase in extracellular IL-1α. Two prediction models (two-group classification model, prediction of LC50 by IC50) were developed and showed promising results. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Toxicity bioassays with concentrated cell culture media-a methodology to overcome the chemical loss by conventional preparation of water samples.

    PubMed

    Niss, Frida; Rosenmai, Anna Kjerstine; Mandava, Geeta; Örn, Stefan; Oskarsson, Agneta; Lundqvist, Johan

    2018-04-01

    The use of in vitro bioassays for studies of toxic activity in environmental water samples is a rapidly expanding field of research. Cell-based bioassays can assess the total toxicity exerted by a water sample, regardless whether the toxicity is caused by a known or unknown agent or by a complex mixture of different agents. When using bioassays for environmental water samples, it is often necessary to concentrate the water samples before applying the sample. Commonly, water samples are concentrated 10-50 times. However, there is always a risk of losing compounds in the sample in such sample preparation. We have developed an alternative experimental design by preparing a concentrated cell culture medium which was then diluted in the environmental water sample to compose the final cell culture media for the in vitro assays. Water samples from five Swedish waste water treatment plants were analyzed for oxidative stress response, estrogen receptor (ER), and aryl hydrocarbon receptor (AhR) activity using this experimental design. We were able to detect responses equivalent to 8.8-11.3 ng/L TCCD for AhR activity and 0.4-0.9 ng/L 17β-estradiol for ER activity. We were unable to detect oxidative stress response in any of the studied water samples. In conclusion, we have developed an experimental design allowing us to examine environmental water samples in toxicity in vitro assays at a concentration factor close to 1, without the risk of losing known or unknown compounds during an extraction procedure.

  9. Effect of increasing bromide concentration on toxicity in treated drinking water.

    PubMed

    Sawade, Emma; Fabris, Rolando; Humpage, Andrew; Drikas, Mary

    2016-04-01

    Research is increasingly indicating the potential chronic health effects of brominated disinfection by-products (DBPs). This is likely to increase with elevated bromide concentrations resulting from the impacts of climate change, projected to include extended periods of drought and the sudden onset of water quality changes. This will demand more rigorous monitoring throughout distribution systems and improved water quality management at water treatment plants (WTPs). In this work the impact of increased bromide concentration on formation of DBPs following conventional treatment and chlorination was assessed for two water sources. Bioanalytical tests were utilised to determine cytotoxicity of the water post disinfection. Coagulation was shown to significantly reduce the cytotoxicity of the water, indicating that removal of natural organic matter DBP precursors continues to be an important factor in drinking water treatment. Most toxic species appear to form within the first half hour following disinfectant addition. Increasing bromide concentration across the two waters was shown to increase the formation of trihalomethanes and shifted the haloacetic acid species distribution from chlorinated to those with greater bromine substitution. This correlated with increasing cytotoxicity. This work demonstrates the challenges faced by WTPs and the possible effects increasing levels of bromide in source waters could have on public health.

  10. Potential toxicity of improperly discarded exhausted photovoltaic cells.

    PubMed

    Motta, C M; Cerciello, R; De Bonis, S; Mazzella, V; Cirino, P; Panzuto, R; Ciaravolo, M; Simoniello, P; Toscanesi, M; Trifuoggi, M; Avallone, B

    2016-09-01

    Low tech photovoltaic panels (PVPs) installed in the early '80s are now coming to the end of their life cycle and this raises the problem of their proper disposal. As panels contain potentially toxic elements, unconventional, complex and costly procedures are required to avoid environmental health risks and in countries where environmental awareness and economic resources are limited this may be especially problematic. This work was designed to investigate potential risks from improper disposal of these panels. To accomplish this aim an exhausted panel was broken into pieces and these were placed in water for 30 days. The resulting leached solution was analyzed to determine chemical release or used in toto, to determine its potential toxicity in established tests. The end points were seed germination (on Cucumis sativus and Lens culinaris) and effects on early development in three larval models: two crustaceans, Daphnia magna and Artemia salina, and the sea urchin Paracentrotus lividus. Our results show that the panels release small amounts of electrolytes (Na, Ca and Mg) into solution, along with antimony and manganese, with a concentration under the accepted maximum contaminant level, and nickel at a potentially toxic concentration. Developmental defects are seen in the plant and animal test organisms after experimental exposure to the whole solution leached from the broken panel. The toxic effects revealed in in vitro tests are sufficient to attract attention considering that they are exerted on both plants and aquatic animals and that the number of old PVPs in disposal sites will be very high. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. An ecological risk assessment of the acute and chronic toxicity of the herbicide picloram to the threatened bull trout (salvelinus confluentus) and the rainbow trout (onchorhyncus mykiss)

    USGS Publications Warehouse

    Fairchild, J.F.; Feltz, K.P.; Sappington, L.C.; Allert, A.L.; Nelson, K.J.; Valle, J.

    2009-01-01

    We conducted acute and chronic toxicity studies of the effects of picloram acid on the threatened bull trout (Salvelinus confluentus) and the standard coldwater surrogate rainbow trout (Oncorhynchus mykiss). Juvenile fish were chronically exposed for 30 days in a proportional flow-through diluter to measured concentrations of 0, 0.30, 0.60, 1.18, 2.37, and 4.75 mg/L picloram. No mortality of either species was observed at the highest concentration. Bull trout were twofold more sensitive to picloram (30-day maximum acceptable toxic concentration of 0.80 mg/L) compared to rainbow trout (30-day maximum acceptable toxic concentration of 1.67 mg/L) based on the endpoint of growth. Picloram was acutely toxic to rainbow trout at 36 mg/L (96-h ALC50). The acute:chronic ratio for rainbow trout exposed to picloram was 22. The chronic toxicity of picloram was compared to modeled and measured environmental exposure concentrations (EECs) using a four-tiered system. The Tier 1, worst-case exposure estimate, based on a direct application of the current maximum use rate (1.1 kg/ha picloram) to a standardized aquatic ecosystem (water body of 1-ha area and 1-m depth), resulted in an EEC of 0.73 mg/L picloram and chronic risk quotients of 0.91 and 0.44 for bull trout and rainbow trout, respectively. Higher-tiered exposure estimates reduced chronic risk quotients 10-fold. Results of this study indicate that picloram, if properly applied according to the manufacturer's label, poses little risk to the threatened bull trout or rainbow trout in northwestern rangeland environments on either an acute or a chronic basis. ?? 2008 Springer Science+Business Media, LLC.

  12. Evaluation of Time- and Concentration-dependent Toxic Effect Models for use in Aquatic Risk Assessments, Oral Presentation

    EPA Science Inventory

    Various models have been proposed for describing the time- and concentration-dependence of toxic effects to aquatic organisms, which would improve characterization of risks in natural systems. Selected models were evaluated using results from a study on the lethality of copper t...

  13. Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

    USGS Publications Warehouse

    Johnson, W. Waynon; Finley, Mack T.

    1980-01-01

    Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates.The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies.Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978a).The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity data

  14. MODELING AIR TOXICS AND PM 2.5 CONCENTRATION FIELDS AS A MEANS FOR FACILITATING HUMAN EXPOSURE ASSESSMENTS

    EPA Science Inventory

    The capability of the US EPA Models-3/Community Multiscale Air Quality (CMAQ) modeling system is extended to provide gridded ambient air quality concentration fields at fine scales. These fields will drive human exposure to air toxics and fine particulate matter (PM2.5) models...

  15. The concentrations of arsenic and other toxic elements in Bangladesh's drinking water.

    PubMed

    Frisbie, Seth H; Ortega, Richard; Maynard, Donald M; Sarkar, Bibudhendra

    2002-11-01

    For drinking water, the people of Bangladesh used to rely on surface water, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases. To reduce the incidences of these diseases, millions of tubewells were installed in Bangladesh since independence in 1971. This recent transition from surface water to groundwater has significantly reduced deaths from waterborne pathogens; however, new evidence suggests disease and death from arsenic (As) and other toxic elements in groundwater are affecting large areas of Bangladesh. In this evaluation, the areal and vertical distribution of As and 29 other inorganic chemicals in groundwater were determined throughout Bangladesh. This study of 30 analytes per sample and 112 samples suggests that the most significant health risk from drinking Bangladesh's tubewell water is chronic As poisoning. The As concentration ranged from < 0.0007 to 0.64 mg/L, with 48% of samples above the 0.01 mg/L World Health Organization drinking water guideline. Furthermore, this study reveals unsafe levels of manganese (Mn), lead (Pb), nickel (Ni), and chromium (Cr). Our survey also suggests that groundwater with unsafe levels of As, Mn, Pb, Ni, and Cr may extend beyond Bangladesh's border into the four adjacent and densely populated states in India. In addition to the health risks from individual toxins, possible multimetal synergistic and inhibitory effects are discussed. Antimony was detected in 98% of the samples from this study and magnifies the toxic effects of As. In contrast, Se and Zn were below our detection limits in large parts of Bangladesh and prevent the toxic effects of As.

  16. Bacillus subtilis as a bioindicator for estimating pentachlorophenol toxicity and concentration.

    PubMed

    Ayude, M A; Okada, E; González, J F; Haure, P M; Murialdo, S E

    2009-05-01

    Pentachlorophenol (PCP) and its sodium salt (Na-PCP) are extremely toxic chemicals responsible for important soil and groundwater pollution, mainly caused by wastes from wood-treatment plants, because chlorinated phenols are widely used as wood preservatives. The methods most commonly used for routine analysis of pesticides such as PCP and Na-PCP are high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS). A variety of rapid biological screening tests using marine organisms, bioluminescent bacteria, and enzymes have also been reported. In this study, rapid biological screening analysis using Bacillus subtilis was developed, to assess the biodegradation of PCP and its by-products in liquid samples. An empirical model is proposed for spectrophotometric analysis of Na-PCP concentration after growth of Bacillus subtilis.

  17. Is ozonation environmentally benign for reverse osmosis concentrate treatment? Four-level analysis on toxicity reduction based on organic matter fractionation.

    PubMed

    Weng, Jingxia; Jia, Huichao; Wu, Bing; Pan, Bingcai

    2018-01-01

    Ozonation is a promising option to treat reverse osmosis concentrate (ROC). However, a systematic understanding and assessment of ozonation on toxicity reduction is insufficient. In this study, ROC sampled from a typical industrial park wastewater treatment plant of China was fractionated into hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON), and hydrophilic fraction (HI). Systematic bioassays covering bacteria, algae, fish, and human cell lines were conducted to reveal the role of ozonation in toxicity variation of the four ROC fractions. HOA in the raw ROC exhibited the highest toxicity, followed by HON and HI. Ozonation significantly reduced total organic carbon (TOC) and UV 254 values in HOA, HON, and HI and their toxicity except in HOB. Correlation analysis indicated that chemical data (TOC and UV 254 ) of HOA and HON correlated well with their toxicities; however, poor correlations were observed for HOB and HI, suggesting that a battery of toxicity assays is necessary. This study indicates that TOC reduction during ozonation could not fully reflect the toxicity issue, and toxicity assessment is required in conjunction with the chemical data to evaluate the effectiveness of ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Effects of biochar addition on toxic element concentrations in plants: A meta-analysis.

    PubMed

    Peng, Xin; Deng, Yinger; Peng, Yan; Yue, Kai

    2018-03-01

    Consuming food contaminated by toxic elements (TEs) could pose a substantial risk to human health. Recently, biochar has been extensively studied as an effective soil ameliorant in situ because of its ability to suppress the phytoavailability of TEs. However, despite the research interest, the effects of biochar applications to soil on different TE concentrations in different plant parts remain unclear. Here, we synthesize 1813 individual observations data collected from 97 articles to evaluate the effects of biochar addition on TE concentrations in plant parts. We found that (1) the experiment type, biochar feedstock and pyrolysis temperature all significantly decreased the TE concentration in plant parts; (2) the responses of Cd and Pb concentrations in edible and indirectly edible plant parts were significantly more sensitive to the effect of biochar than the Zn, Ni, Mn, Cr, Co and Cu concentrations; and (3) the biochar dosage and surface area, significantly influenced certain TE concentrations in plant tissues as determined via correlation analysis. Moreover, the only exception in this study was found for metalloid element (i.e., As) concentrations in plants, which were not significantly influenced by biochar addition. Overall, the effects of biochar on TE concentrations in plant tissues were negative, at least on average, and the central trends suggest that biochar has a considerable ability to mitigate the transfer of TEs to food, thereby reducing the associated health risks. Our results provide an initial quantitative determination of the effects of biochar addition on multifarious TEs in different plant parts as well as an assessment of the ability of biochar to reduce TE concentrations in plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Toxicity risk assessment of mercury, DDT and arsenic legacy pollution in sediments: A triad approach under low concentration conditions.

    PubMed

    Marziali, L; Rosignoli, F; Drago, A; Pascariello, S; Valsecchi, L; Rossaro, B; Guzzella, L

    2017-09-01

    The determination of sediment toxicity is challenging due to site-specific factors affecting pollutants distribution and bioavailability, especially when contamination levels are close to expected non-effect concentrations. Different lines of evidence and sensitive tools are necessary for a proper toxicity risk assessment. We examined the case study of the Toce River (Northern Italy), where past industrial activities determined Hg, DDT and As enrichment in sediments. A triad approach comprising chemical, ecotoxicological and ecological analyses (benthic invertebrates) was carried out for risk assessment of residual contamination in river sediments. A "blank" site upstream from the industrial site was selected to compare the other sites downstream. Sediment, water and benthic invertebrate samplings were carried out following standard protocols. Results emphasized that despite the emissions of the industrial site ceased about 20years ago, sediments in the downstream section of the river remain contaminated by Hg, DDT and As with concentrations exceeding Threshold Effect Concentrations. A chronic whole-sediment test with Chironomus riparius showed decreased development rate and a lower number of eggs per mass in the contaminated sediments. Benthic community was analyzed with the calculation of integrated (STAR_ICMi) and stressor-specific metrics (SPEAR pesticide and mean sensitivity to Hg), but no significant differences were found between upstream and downstream sites. On the other hand, multivariate analysis (partial Redundancy Analysis and variation partitioning) emphasized a slight impact on invertebrate community, accounting for 5% variation in taxa composition. Results show that legacy contaminants in sediments, even at low concentrations, may be bioavailable and possibly toxic for benthic invertebrates. At low concentration levels, sensitive and site-specific tools need to be developed for a proper risk analysis. Copyright © 2017 Elsevier B.V. All rights

  20. Toxicological approach to setting spacecraft maximum allowable concentrations for carbon monoxide

    NASA Technical Reports Server (NTRS)

    Wong, K. L.; Limero, T. F.; James, J. T.

    1992-01-01

    The Spacecraft Maximum Allowable Concentrations (SMACs) are exposure limits for airborne chemicals used by NASA in spacecraft. The aim of these SMACs is to protect the spacecrew against adverse health effects and performance decrements that would interfere with mission objectives. Because of the 1 and 24 hr SMACs are set for contingencies, minor reversible toxic effects that do not affect mission objectives are acceptable. The 7, 30, or 180 day SMACs are aimed at nominal operations, so they are established at levels that would not cause noncarcinogenic toxic effects and more than one case of tumor per 1000 exposed individuals over the background. The process used to set the SMACs for carbon monoxide (CO) is described to illustrate the approach used by NASA. After the toxicological literature on CO was reviewed, the data were summarized and separated into acute, subchronic, and chronic toxicity data. CO's toxicity depends on the formation of carboxyhemoglobin (COHb) in the blood, reducing the blood's oxygen carrying capacity. The initial task was to estimate the COHb levels that would not produce toxic effects in the brain and heart.

  1. Correlations between homologue concentrations of PCDD/Fs and toxic equivalency values in laboratory-, package boiler-, and field-scale incinerators.

    PubMed

    Iino, Fukuya; Takasuga, Takumi; Touati, Abderrahmane; Gullett, Brian K

    2003-01-01

    The toxic equivalency (TEQ) values of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are predicted with a model based on the homologue concentrations measured from a laboratory-scale reactor (124 data points), a package boiler (61 data points), and operating municipal waste incinerators (114 data points). Regardless of the three scales and types of equipment, the different temperature profiles, sampling emissions and/or solids (fly ash), and the various chemical and physical properties of the fuels, all the PCDF plots showed highly linear correlations (R(2)>0.99). The fitting lines of the reactor and the boiler data were almost linear with slope of unity, whereas the slope of the municipal waste incinerator data was 0.86, which is caused by higher predicted values for samples with high measured TEQ. The strong correlation also implies that each of the 10 toxic PCDF congeners has a constant concentration relative to its respective total homologue concentration despite a wide range of facility types and combustion conditions. The PCDD plots showed significant scatter and poor linearity, which implies that the relative concentration of PCDD TEQ congeners is more sensitive to variations in reaction conditions than that of the PCDF congeners.

  2. Lower tier toxicity risk assessment of agriculture pesticides detected on the Río Madre de Dios watershed, Costa Rica.

    PubMed

    Arias-Andrés, M; Rämö, R; Mena Torres, F; Ugalde, R; Grandas, L; Ruepert, C; Castillo, L E; Van den Brink, P J; Gunnarsson, J S

    2016-10-25

    Costa Rica is a tropical country with one of the highest biodiversity on Earth. It also has an intensive agriculture, and pesticide runoff from banana and pineapple plantations may cause a high toxicity risk to non-target species in rivers downstream the plantations. We performed a first tier risk assessment of the maximum measured concentrations of 32 pesticides detected over 4 years in the River Madre de Dios (RMD) and its coastal lagoon on the Caribbean coast of Costa Rica. Species sensitivity distributions (SSDs) were plotted in order to derive HC 5 values for each pesticide, i.e., hazard concentrations for 5 % of the species, often used as environmental criteria values in other countries. We also carried out toxicity tests for selected pesticides with native Costa Rican species in order to calculate risk coefficients according to national guidelines in Costa Rica. The concentrations of herbicides diuron and ametryn and insecticides carbofuran, diazinon, and ethoprophos exceeded either the HC 5 value or the lower limit of its 90 % confidence interval suggesting toxic risks above accepted levels. Risk coefficients of diuron and carbofuran derived using local guidelines indicate toxicity risks as well. The assessed fungicides did not present acute toxic risks according to our analysis. Overall, these results show a possible toxicity of detected pesticides to aquatic organisms and provide a comparison of Costa Rican national guidelines with more refined methods for risk assessment based on SSDs. Further higher tier risk assessments of pesticides in this watershed are also necessary in order to consider pesticide water concentrations over time, toxicity from pesticide mixtures, and eventual effects on ecosystem functions.

  3. Spatiotemporal trend analysis of metal concentrations in sediments of a residential California stream with toxicity and regulatory implications.

    PubMed

    Hall, Lenwood W; Anderson, Ronald D; Killen, William D

    2017-06-07

    The objective of this study was to determine if concentrations of arsenic, cadmium, chromium, copper, lead, nickel and zinc measured in the sediments of a residential stream in California (Pleasant Grove Creek) have changed temporally or spatially from 2006 to 2016. Threshold Effect Levels (TELs), conservative ecological effects benchmarks, and exceedances for the seven metals were also evaluated over the 11-year time period to provide insight into potential metal toxicity to resident benthic communities. In addition, the bioavailability of metals in sediments was also determined by calculating Simultaneous Extracted Metal/Acid Volatle Sulfide (SEM/AVS) ratios to allow an additional assessment of toxicity. Regulatory implications of this data set and the role of metal toxicity are also discussed. Stream-wide temporal trend analysis showed no statistically significant trends for any of the metals. However, spatial analysis for several sites located near storm drains did show a significant increase for most metals over the 11-year period. TEL exceedances during the 7 years of sampling, spanning 2006-2016, were reported for all metals with the number of exceedances ranging from 47 for copper and zinc to 1 for lead. A spatial analysis showed that the highest number of TEL exceedances and the highest number of SEM/AVS ratios greater than one with at least one metal exceeding a TEL occurred at upstream sites. The potentially toxic metal concentrations reported in Pleasant Grove Creek should be used in the 303 (d) listing process for impaired water bodies in California.

  4. Concentration-dependent toxicity effect of SDBS on swimming behavior of freshwater fishes.

    PubMed

    Zhang, Ying; Ma, Jing; Zhou, Siyun; Ma, Fang

    2015-07-01

    Sodium dodecyl benzene sulfonate (SDBS) is a kind of widely used anionic surfactant and its discharge may pose potential risk to the receiving aquatic ecosystem. The aim of our study is to investigate the toxic effect of SDBS on fish swimming behavior quantitatively, followed by examination whether there are significant differences of swimming behavior among applied fish species (i.e. zebra fish (Danio rerio), Japanese medaka (Oryzias latipes) and red carp (Cyprinus carpio)). The swimming speed and vertical position were analyzed after the fish exposed to SDBS aiming to reflect the toxicity of SDBS on fish. Our results showed that the swimming behavior of three fishes was significantly affected by SDBS, although there were slight differences of swimming pattern changes among three fish species when they exposed to the same concentration of SDBS. It could be seen that red carp, one of the native fish species in China, can be used as a model fish to reflect the water quality changes as well as zebra fish and Japanese medaka which are commonly used as model fishes. Our study also illustrated that the swimming behavior monitoring may have a good application prospect in pre-warning of water quality. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. SEDIMENT TOXICITY ASSESSMENT: COMPARISON OF STANDARD AND NEW TESTING DESIGNS

    EPA Science Inventory

    Standard methods of sediment toxicity testing are fairly well accepted; however, as with all else, evolution of these methods is inevitable. We compared a standard ASTM 10-day amphipod toxicity testing method with smaller, 48- and 96-h test methods using very toxic and reference ...

  6. Assessing the concentrations and risks of toxicity from the antibiotics ciprofloxacin, sulfamethoxazole, trimethoprim and erythromycin in European rivers.

    PubMed

    Johnson, Andrew C; Keller, Virginie; Dumont, Egon; Sumpter, John P

    2015-04-01

    This study evaluated the potential concentrations of four antibiotics: ciprofloxacin (CIP), sulfamethoxazole (SUF), trimethoprim (TRI) and erythromycin (ERY) throughout the rivers of Europe. This involved reviewing national consumption rates together with assessing excretion and sewage treatment removal rates. From this information, it was possible to construct best, expected and worst case scenarios for the discharge of these antibiotics into rivers. Consumption data showed surprising variations, up to 200-fold in the popularity of different antibiotics across different European nations. Using the water resources model GWAVA which has a spatial resolution of approximately 6×9 km, river water concentrations throughout Europe were predicted based on 31-year climate data. The modelled antibiotic concentrations were within the range of measurements reported previously in European effluents and rivers. With the expected scenario, the predicted annual-average antibiotic concentrations ranged between 0 and 10 ng/L for 90% by length of surface waters. In the worst case scenario concentrations could reach between 0.1 and 1 μg/L at the most exposed locations. As both predicted and observed sewage effluent concentrations were below reported effect levels for the most sensitive aquatic wildlife, no direct toxicity in rivers is expected. Predicted river concentrations for CIP and ERY were closest to effect levels in wildlife, followed by SUF which was 2-3 orders of magnitude lower. TRI appeared to be of the least concern with around 6 orders of magnitude difference between predicted and effect levels. However, mixture toxicity may elevate this risk and antibiotic levels of 0.1-1 μg/L in hotspots may contribute to local environmental antibiotic resistance in microorganisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Comparison of short-term chronic and chronic silver toxicity to fathead minnows in unamended and sodium chloride-amended waters.

    PubMed

    Naddy, Rami B; Rehner, Anita B; McNerney, Gina R; Gorsuch, Joseph W; Kramer, James R; Wood, Chris M; Paquin, Paul R; Stubblefield, William A

    2007-09-01

    The chronic (early life stage [ELS]) and short-term chronic (STC) toxicity of silver (as silver nitrate) to fathead minnows (FHM) was determined concurrently in flow-through exposures (33 volume additions/d). Paired ELS (approximately 30 d) and STC (7 d) studies were conducted with and without the addition of 60 mg/L Cl (as NaCl). The paired studies in unamended water were later repeated using standard flow conditions (9 volume additions/d). The purpose of the paired studies was to determine if short-term chronic endpoints can be used to predict effects in ELS studies. For each experiment, a "split-chamber" design (organisms were held in a common exposure chamber) allowed the direct comparison between short-term and chronic exposures. It appeared that the chronic toxicity of silver was mitigated to some extent by NaCl addition. The maximum acceptable toxicant concentration for growth in the ELS study was 0.53 microg dissolved Ag/L under standard flow conditions. Early life stage and STC endpoints in all three studies typically agreed within a factor of two. Whole-body sodium and silver concentrations measured in individual fathead minnows during these studies showed an increase in silver body burdens and a decrease in sodium concentration. These results indicate that the STC study could be used as a surrogate test to estimate chronic toxicity and that the mechanism of chronic silver toxicity may be the same as for acute toxicity.

  8. Therapeutic and toxic blood concentrations of nearly 1,000 drugs and other xenobiotics

    PubMed Central

    2012-01-01

    Introduction In order to assess the significance of drug levels measured in intensive care medicine, clinical and forensic toxicology, as well as for therapeutic drug monitoring, it is essential that a comprehensive collection of data is readily available. Therefore, it makes sense to offer a carefully referenced compilation of therapeutic and toxic plasma concentration ranges, as well as half-lives, of a large number of drugs and other xenobiotics for quick and comprehensive information. Methods Data have been abstracted from original papers and text books, as well as from previous compilations, and have been completed with data collected in our own forensic and clinical toxicology laboratory. The data presented in the table and corresponding annotations have been developed over the past 20 years and longer. A previous compilation has been completely revised and updated. In addition, more than 170 substances, especially drugs that have been introduced to the market since 2003 as well as illegal drugs, which became known to cause intoxications, were added. All data were carefully referenced and more than 200 new references were included. Moreover, the annotations providing details were completely revised and more than 100 annotations were added. Results For nearly 1,000 drugs and other xenobiotics, therapeutic ("normal") and, if data were available, toxic and comatose-fatal blood-plasma concentrations and elimination half-lives were compiled in a table. Conclusions In case of intoxications, the concentration of the ingested substances and/or metabolites in blood plasma better predicts the clinical severity of the case when compared to the assumed amount and time of ingestion. Comparing and contrasting the clinical case against the data provided, including the half-life, may support the decision for or against further intensive care. In addition, the data provided are useful for the therapeutic monitoring of pharmacotherapies, to facilitate the diagnostic assessment

  9. Intra- and interlaboratory variability in acute toxicity tests with glochidia and juveniles of freshwater mussels (Unionidae)

    USGS Publications Warehouse

    Wang, N.; Augspurger, T.; Barnhart, M.C.; Bidwell, Joseph R.; Cope, W.G.; Dwyer, F.J.; Geis, S.; Greer, I.E.; Ingersoll, C.G.; Kane, C.M.; May, T.W.; Neves, R.J.; Newton, T.J.; Roberts, A.D.; Whites, D.W.

    2007-01-01

    The present study evaluated the performance and variability in acute toxicity tests with glochidia and newly transformed juvenile mussels using the standard methods outlined in American Society for Testing and Materials (ASTM). Multiple 48-h toxicity tests with glochidia and 96-h tests with juvenile mussels were conducted within a single laboratory and among five laboratories. All tests met the test acceptability requirements (e.g., ???90% control survival). Intralaboratory tests were conducted over two consecutive mussel-spawning seasons with mucket (Actinonaias ligamentina) or fatmucket (Lampsilis siliquoidea) using copper, ammonia, or chlorine as a toxicant. For the glochidia of both species, the variability of intralaboratory median effective concentrations (EC50s) for the three toxicants, expressed as the coefficient of variation (CV), ranged from 14 to 27% in 24-h exposures and from 13 to 36% in 48-h exposures. The intralaboratory CV of copper EC50s for juvenile fatmucket was 24% in 48-h exposures and 13% in 96-h exposures. Interlaboratory tests were conducted with fatmucket glochidia and juveniles by five laboratories using copper as a toxicant. The interlaboratory CV of copper EC50s for glochidia was 13% in 24-h exposures and 24% in 48-h exposures, and the interlaboratory CV for juveniles was 22% in 48-h exposures and 42% in 96-h exposures. The high completion success and the overall low variability in test results indicate that the test methods have acceptable precision and can be performed routinely. ?? 2007 SETAC.

  10. CORRELATIONS BETWEEN HOMOLOGUE CONCENTRATIONS OF PCDD/FS AND TOXIC EQUIVALENCY VALUES IN LABORATORY-, PACKAGE BOILER-, AND FIELD-SCALE INCINERATORS

    EPA Science Inventory

    The toxic equivalency (TEQ) values of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are predicted with a model based on the homologue concentrations measured from a laboratory-scale reactor (124 data points), a package boiler (61 data points), and ...

  11. Calculation and evaluation of sediment effect concentrations for the amphipod Hyalella azteca and the midge Chironomus riparius

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Haverland, Pamela S.; Brunson, Eric L.; Canfield, Timothy J.; Dwyer, F. James; Henke, Chris; Kemble, Nile E.; Mount, David R.; Fox, Richard G.

    1996-01-01

    calculated using sediment concentrations normalized to total organic carbon (TOC) concentrations did not improve the reliability compared to SECs calculated using dry-weight concentrations. The range of TOC concentrations in our database was relatively narrow compared to the ranges of contaminant concentrations. Therefore, normalizing dry-weight concentrations to a relatively narrow range of TOC concentrations had little influence on relative concentra of contaminants among samples. When SECs are used to conduct a preliminary screening to predict the potential for toxicity in the absence of actual toxicity testing, a low number of SEC exceedances should be used to minimize the potential for false negatives; however, the risk of accepting higher false positives is increased.

  12. Comparison of extracts and toxicities of organic compounds in drinking water concentrated by single and composite XAD resins.

    PubMed

    Zhou, Xue; Xiang, Lunhui; Wu, Fenghong; Peng, Xiaoling; Xie, Hong; Wang, Jiachun; Yang, Kedi; Lu, Wenqing; Wu, Zhigang

    2013-12-01

    We compared extracts and toxicities of organic compounds (OCs) in drinking water concentrated by composite XAD-2/8 resin (mixed with an equal volume of XAD-2 and XAD-8 resins) with those extracted by single XAD-2 (non-polar) and XAD-8 (polar) resins. Drinking water was processed from raw water of the Han River and the Yangtze River in Wuhan section, China. The extraction efficiency of all resins was controlled at 30%. The types of extracted OCs were detected by gas chromatography-mass spectrometry, and the cytotoxicity and genotoxicity were assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and comet assays, respectively, in human hepatoma HepG2 cells. Our results showed that XAD-2/8 extracted a larger variety of OCs, compared with XAD-8 and XAD-2. The cytotoxicity and genotoxicity of extracted OCs were in the order of XAD-8> XAD-2/8> XAD-2 at almost all tested concentrations after 24 h treatment (P < 0.05). Our findings suggest that single XAD resin selectively extracts either polar or non-polar OCs, which would lead to over- or under-estimation of the toxicity of drinking water. Nevertheless, composite resin extracts both polar and non-polar OCs, and could be utilized as a useful extraction technique to evaluate the level and toxicity of OCs in drinking water.

  13. Toxicity of seabird guano to sea urchin embryos and interaction with Cu and Pb.

    PubMed

    Rial, Diego; Santos-Echeandía, Juan; Álvarez-Salgado, Xosé Antón; Jordi, Antoni; Tovar-Sánchez, Antonio; Bellas, Juan

    2016-02-01

    Guano is an important source of marine-derived nutrients to seabird nesting areas. Seabirds usually present high levels of metals and other contaminants because the bioaccumulation processes and biotic depositions can increase the concentration of pollutants in the receiving environments. The objectives of this study were to investigate: the toxicity of seabird guano and the joint toxicity of guano, Cu and Pb by using the sea urchin embryo-larval bioassay. In a first experiment, aqueous extracts of guano were prepared at two loading rates (0.462 and 1.952 g L(-1)) and toxicity to sea-urchin embryos was tested. Toxicity was low and not dependent of the load of guano used (EC50 0.42 ± 0.03 g L(-1)). Trace metal concentrations were also low either in guano or in aqueous extracts of guano and the toxicity of extracts were apparently related to dissolved organic matter. In a second experiment, the toxicity of Cu-Pb mixtures in artificial seawater and in extracts of guano (at two loadings: 0.015 and 0.073 g L(-1)), was tested. According to individual fittings, Cu added to extracts of guano showed less toxicity than when dissolved in artificial seawater. The response surfaces obtained for mixtures of Cu and Pb in artificial seawater, and in 0.015 g L(-1) and 0.073 g L(-1) of guano, were better described by Independent Action model adapted to describe antagonism, than by the other proposed models. This implied accepting that EC50 for Cu and Pb increased with the load of guano and with a greater interaction for Cu than for Pb. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. LINKING AIR TOXIC CONCENTRATIONS FROM CMAQ TO THE HAPEM5 EXPOSURE MODEL AT NEIGHORHOOD SCALES FOR THE PHILADELPHIA AREA

    EPA Science Inventory

    This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multi-scale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For ...

  15. Aquatic toxicity and biodegradability of a surfactant produced by Bacillus subtilis ICA56.

    PubMed

    De Oliveira, Darlane W F; Cara, Alejandro B; Lechuga-Villena, Manuela; García-Román, Miguel; Melo, Vania M M; Gonçalves, Luciana R B; Vaz, Deisi A

    2017-01-28

    In this work, the environmental compatibility of a biosurfactant produced by a Bacillus subtilis strain isolated from the soil of a Brazilian mangrove was investigated. The biosurfactant, identified as surfactin, is able to reduce surface tension (ST) to 31.5 ± 0.1 mN m -1 and exhibits a lowcritical micelle concentration (CMC) value (0.015 ± 0.003 g L -1 ). The highest crude biosurfactant concentration (224.3 ± 1.9 mg L -1 ) was reached at 72 h of fermentation. Acute toxicity tests, carried out with Daphnia magna, Vibrio fischeri and Selenastrum capricornutum indicated that the toxicity of the biosurfactant is lower than that of its chemically derived counterparts. The results of the biodegradability tests demonstrated that the crude surfactin extract was degraded by both Pseudomonas putida and a mixed population from a sewage-treatment plant, in both cases the biodegradation efficiency being dependent on the initial concentration of the biosurfactant. Finally, as the biodegradation percentages obtained fall within the acceptance limits established by the Organization for Economic Co-operation and Development (Guidelines for Testing of Chemicals, OECD 301E), crude surfactin can be classified as a "readily" biodegradable compound.

  16. The Simplest Flowchart Stating the Mechanisms for Organic Xenobiotics-induced Toxicity: Can it Possibly be Accepted as a "Central Dogma" for Toxic Mechanisms?

    PubMed

    Park, Yeong-Chul; Lee, Sundong; Cho, Myung-Haing

    2014-09-01

    Xenobiotics causing a variety of toxicity in biological systems could be classified as two types, inorganic and organic chemicals. It is estimated that the organic xenobiotics are responsible for approximately 80~90% of chemical-induced toxicity in human population. In the class for toxicology, we have encountered some difficulties in explaining the mechanisms of toxicity caused especially by organic chemicals. Here, a simple flowchart was introduced for explaining the mechanism of toxicity caused by organic xenobiotics, as the central dogma of molecular biology. This flowchart, referred to as a central dogma, was described based on a view of various aspects as follows: direct-acting chemicals vs. indirect-acting chemicals, cytochrome P450-dependent vs. cytochrome P450-independent biotransformation, reactive intermediates, reactivation, toxicokinetics vs. toxicodynamics, and reversibility vs. irreversibility. Thus, the primary objective of this flowchart is to help better understanding of the organic xenobiotics-induced toxic mechanisms, providing a major pathway for toxicity occurring in biological systems.

  17. Prevalidation of an Acute Inhalation Toxicity Test Using the EpiAirway In Vitro Human Airway Model.

    PubMed

    Jackson, George R; Maione, Anna G; Klausner, Mitchell; Hayden, Patrick J

    2018-06-01

    Introduction: Knowledge of acute inhalation toxicity potential is important for establishing safe use of chemicals and consumer products. Inhalation toxicity testing and classification procedures currently accepted within worldwide government regulatory systems rely primarily on tests conducted in animals. The goal of the current work was to develop and prevalidate a nonanimal ( in vitro ) test for determining acute inhalation toxicity using the EpiAirway™ in vitro human airway model as a potential alternative for currently accepted animal tests. Materials and Methods: The in vitro test method exposes EpiAirway tissues to test chemicals for 3 hours, followed by measurement of tissue viability as the test endpoint. Fifty-nine chemicals covering a broad range of toxicity classes, chemical structures, and physical properties were evaluated. The in vitro toxicity data were utilized to establish a prediction model to classify the chemicals into categories corresponding to the currently accepted Globally Harmonized System (GHS) and the Environmental Protection Agency (EPA) system. Results: The EpiAirway prediction model identified in vivo rat-based GHS Acute Inhalation Toxicity Category 1-2 and EPA Acute Inhalation Toxicity Category I-II chemicals with 100% sensitivity and specificity of 43.1% and 50.0%, for GHS and EPA acute inhalation toxicity systems, respectively. The sensitivity and specificity of the EpiAirway prediction model for identifying GHS specific target organ toxicity-single exposure (STOT-SE) Category 1 human toxicants were 75.0% and 56.5%, respectively. Corrosivity and electrophilic and oxidative reactivity appear to be the predominant mechanisms of toxicity for the most highly toxic chemicals. Conclusions: These results indicate that the EpiAirway test is a promising alternative to the currently accepted animal tests for acute inhalation toxicity.

  18. Deriving allowable daily intakes for systemic toxicants lacking chronic toxicity data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Layton, D.W.; Mallon, B.J.; Rosenblatt, D.H.

    1987-03-01

    The lack of human toxicological data for most chemical compounds makes it difficult to quickly assess health risks associated with exposure to contaminants at hazardous waste sites. It would therefore be advantageous to have a technique for estimating acceptable daily intakes (ADIs) of potentially toxic substances based on more widely available animal toxicity data. This article focuses on the use of LD50 data to derive provisional ADIs, and it suggests multiplying oral LD50 values (expressed in mg/kg of body wt) by a factor in the range of 5 X 10(-6) to 1 X 10(-5) day-1 to convert them to suchmore » ADIs. It is emphasized that these interim ADI values are no substitute for toxicity testing, but that such testing would most likely result in higher ADI estimates.« less

  19. High concentrations of protein test substances may have non-toxic effects on Daphnia magna: implications for regulatory study designs and ecological risk assessments for GM crops.

    PubMed

    Raybould, Alan; Burns, Andrea; Hamer, Mick

    2014-01-01

    Laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (NTOs) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (IRGM) crops. To increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for NTOs are exposed to concentrations of insecticidal proteins that are in excess of worst-case predicted exposures in the field. High concentrations in effects tests are achieved by using protein test substances produced in microbes, such as Escherichia coli. In a study that exposed Daphnia magna to a single high concentration of a microbial test substance containing Vip3Aa20, the insecticidal protein in MIR162 maize, small reductions in growth were observed. These effects were surprising as many other studies strongly suggest that the activity of Vip3Aa20 is limited to Lepidoptera. A plausible explanation for the effect on growth is that high concentrations of test substance have a non-toxic effect on Daphnia, perhaps by reducing its feeding rate. A follow-up study tested that hypothesis by exposing D. magna to several concentrations of Vip3Aa20, and a high concentration of a non-toxic protein, bovine serum albumin (BSA). Vip3Aa20 and BSA had sporadic effects on the reproduction and growth of D. magna. The pattern of the effects suggests that they result from non-toxic effects of high concentrations of protein, and not from toxicity. The implications of these results for regulatory NTO effects testing and ERA of IRGM crops are discussed.

  20. Developmental Toxicity Evaluations of Whole Mixtures of Disinfection By-products using Concentrated Drinking Water in Rats: Gestational and Lactational Effects of Sulfate and Sodium

    EPA Science Inventory

    A developmental toxicity bioassay was used in three experiments to evaluate drinking water concentrates for suitability in multigenerational studies. First, chlorinated water was concentrated 135 fold by reverse osmosis; select lost disinfection by-products were spiked back. Co...

  1. Developmental Toxicity Evaluations of Whole Mixtures of Disinfection By-products using Concentrated Drinking Water in Rats: Gestational and Lactational Effects of Sulfate and Sodium*

    EPA Science Inventory

    A developmental toxicity bioassay was used in three experiments to evaluate drinking water concentrates for suitability in multigenerational studies. First, chlorinated water was concentrated 135 fold by reverse osmosis; select lost disinfection by-products were spiked back. Conc...

  2. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea.

    PubMed

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-08-05

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  3. Defences against ammonia toxicity in tropical air-breathing fishes exposed to high concentrations of environmental ammonia: a review.

    PubMed

    Ip, Y K; Chew, S F; Wilson, J M; Randall, D J

    2004-10-01

    In the tropics, air-breathing fishes can be exposed to environmental ammonia when stranded in puddles of water during the dry season, during a stay inside a burrow, or after agricultural fertilization. At low concentrations of environmental ammonia, NH(3) excretion is impeded, as in aerial exposure, leading to the accumulation of endogenous ammonia. At high concentrations of environmental ammonia, which results in a reversed NH(3) partial pressure gradient (DeltaP(NH3)), there is retention of endogenous ammonia and uptake of exogenous ammonia. In this review, several tropical air-breathing fishes (giant mudskipper, African catfish, oriental weatherloach, swamp eel, four-eyed sleeper, abehaze and slender African lungfish), which can tolerate high environmental ammonia exposure, are used as examples to demonstrate how eight different adaptations can be involved in defence against ammonia toxicity. Four of these adaptations deal with ammonia toxicity at branchial and/or epithelial surfaces: (1) active excretion of NH(4)(+); (2) lowering of environmental pH; (3) low NH(3) permeability of epithelial surfaces; and (4) volatilization of NH(3), while another four adaptations ameliorate ammonia toxicity at the cellular and subcellular levels: (5) high tolerance of ammonia at the cellular and subcellular levels; (6) reduction in ammonia production; (7) glutamine synthesis; and (8) urea synthesis. The responses of tropical air-breathing fishes to high environmental ammonia are determined apparently by behavioural adaptations and the nature of their natural environments.

  4. A Perspective on the Toxicity of Low Concentrations of Petroleum-Derived Polycyclic Aromatic Hydrocarbons to Early Life Stages of Herring and Salmon

    PubMed Central

    Page, David S.; Chapman, Peter M.; Landrum, Peter F.; Neff, Jerry; Elston, Ralph

    2012-01-01

    This article presents a critical review of two groups of studies that reported adverse effects to salmon and herring eggs and fry from exposure to 1 μg/L or less of aqueous total polycyclic aromatic hydrocarbons (TPAH), as weathered oil, and a more toxic aqueous extract of “very weathered oil.” Exposure media were prepared by continuously flowing water up through vertical columns containing gravel oiled at different concentrations of Prudhoe Bay crude oil. Uncontrolled variables associated with the use of the oiled gravel columns included time- and treatment-dependent variations in the PAH concentration and composition in the exposure water, unexplored toxicity from other oil constituents/degradation products, potential toxicity from bacterial and fungal activity, oil droplets as a potential contaminant source, inherent differences between control and exposed embryo populations, and water flow rate differences. Based on a review of the evidence from published project reports, peer-reviewed publications, chemistry data in a public database, and unpublished reports and laboratory records, the reviewed studies did not establish consistent dose (concentration) response or causality and thus do not demonstrate that dissolved PAH alone from the weathered oil resulted in the claimed effects on fish embryos at low μg/L TPAH concentrations. Accordingly, these studies should not be relied on for management decision-making, when assessing the risk of very low–level PAH exposures to early life stages of fish. PMID:22754275

  5. The relationship between historical development and potentially toxic element concentrations in urban soils.

    PubMed

    McIlwaine, Rebekka; Doherty, Rory; Cox, Siobhan F; Cave, Mark

    2017-01-01

    Increasing urbanisation has a direct impact on soil quality, resulting in elevated concentrations of potentially toxic elements (PTEs) in soils. This research aims to assess if soil PTE concentrations can be used as an 'urbanisation tracer' by investigating geogenic and anthropogenic source contributions and controls, and considering PTE enrichment across historical urban development zones. The UK cities of Belfast and Sheffield are chosen as study areas, where available shallow and deep concentrations of PTEs in soil are compared to identify geogenic and anthropogenic contributions to PTEs. Cluster analysis and principal component analysis are used to elucidate the main controls over PTE concentrations. Pollution indices indicate that different periods of historical development are linked to enrichment of different PTEs. Urban subdomains are identified and background values calculated using various methodologies and compared to generic site assessment criteria. Exceedances for a number of the PTEs considered suggest a potential human health risk could be posed across subdomains of both Belfast and Sheffield. This research suggests that airborne diffuse contamination from often historical sources such as traffic, domestic combustion and industrial processes contribute greatly to soil contamination within urban environments. The relationship between historical development and differing PTEs is a novel finding, suggesting that PTEs have the potential for use as 'urbanisation tracers'. The investigative methodology employed has potential applications for decision makers, urban planners, regulators and developers of urban areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Identification of acute toxicants in New Bedford Harbor sediments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ho, K.T.; McKinney, R.A.; Kuhn, A.

    1997-03-01

    New Bedford Harbor (NBH) is a marine Superfund site contaminated with high concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and metals. Experiments were conducted to determine the causal toxic agent(s) in pore waters from New Bedford Harbor sediments to amphipods and mysid shrimp. Chemical manipulations to characterize toxicity revealed that pore-water toxicity was organic in nature. Fractionation and subsequent mass spectral identification of peaks in the toxic fraction indicated that PCBs. PAHs, and unknown compounds were present. Comparisons of PAH LC50s and PAH concentrations in this fraction indicated that the toxicity was not due to PAHs because themore » PAH concentrations were much lower than the reported PAH LC50s. One unknown peak was positively identified as bis(2-ethylhexyl) phthalate, and the other tentatively identified as pyrazole. Toxicity tests and comparison of toxicity in the blank and toxic fractions eliminated the two unknowns as toxic causal agents. The authors determined the range of PCB LC50s to fall between 10 and 110 ppb for Mysidopsis bahia and Ampelisca abdita. Concentrations of PCBs for the toxic fractions ranged from 12 to 27 ppb. This range falls within the observed PCB LC50s for M. bahia and A. abdita. Based upon these PCB concentrations, they concluded that PCBs were the acute toxic agents in NBH pore waters. Other compounds in the toxic fractions, or compounds that coeluted and were undistinguished from PCBs had minor contributions to the measured toxicity.« less

  7. Endothelial Function and Serum Concentration of Toxic Metals in Frequent Consumers of Fish

    PubMed Central

    Buscemi, Silvio; Vasto, Sonya; Di Gaudio, Francesca; Grosso, Giuseppe; Bergante, Sonia; Galvano, Fabio; Massenti, Fatima Maria; Amodio, Emanuele; Rosafio, Giuseppe; Verga, Salvatore

    2014-01-01

    Background Endothelial dysfunction is involved in the pathogenesis of atherosclerosis. Consumption of fish is associated with reduced cardiovascular risk, but there is paucity of data concerning its effect on endothelial function. Furthermore, investigation of the effects of fish consumption on health must take into account the ingestion of contaminants, including transition metals and some metalloids, which may have unfavorable effects on health, including those on the cardiovascular system. We investigated the association between fish consumption, endothelial function (flow mediated dilation of the brachial artery), and serum concentration of some toxic metals in apparently healthy people. Methods Twenty-nine high fish consumers (at least 3 portions a week) were compared with 25 low fish consumers (less than 1 portion a week). All participants were free of diabetes, cardiovascular or other systemic diseases. Serum metal (antimonium, arsenic, mercury, lead, cobalt, copper, zinc, selenium, strontium) concentrations were measured in subgroups of 24 high fish consumers and 19 low fish consumers. Results Both groups exhibited similar habitual dietary patterns, age and anthropometric characteristics. The high fish consumers had higher flow mediated dilation (9.7±1.8 vs. 7.3±1.9%; P<0.001), but also higher serum concentrations of mercury (5.87±2.69 vs. 1.65±1.10 mcg/L; P<0.001) and arsenic (6.04±3.25 vs. 2.30±1.58 mcg/L; P<0.001). The fasting plasma glucose concentrations were significantly correlated with both mercury (r = 0.39; P = 0.01) and arsenic concentrations (r = 0.55; P<0.001). Conclusions Habitual consumption of high amounts of fish is associated with better endothelial function despite higher serum concentrations of mercury and arsenic. PMID:25401695

  8. Prevalidation of an Acute Inhalation Toxicity Test Using the EpiAirway In Vitro Human Airway Model

    PubMed Central

    Jackson, George R.; Maione, Anna G.; Klausner, Mitchell

    2018-01-01

    Abstract Introduction: Knowledge of acute inhalation toxicity potential is important for establishing safe use of chemicals and consumer products. Inhalation toxicity testing and classification procedures currently accepted within worldwide government regulatory systems rely primarily on tests conducted in animals. The goal of the current work was to develop and prevalidate a nonanimal (in vitro) test for determining acute inhalation toxicity using the EpiAirway™ in vitro human airway model as a potential alternative for currently accepted animal tests. Materials and Methods: The in vitro test method exposes EpiAirway tissues to test chemicals for 3 hours, followed by measurement of tissue viability as the test endpoint. Fifty-nine chemicals covering a broad range of toxicity classes, chemical structures, and physical properties were evaluated. The in vitro toxicity data were utilized to establish a prediction model to classify the chemicals into categories corresponding to the currently accepted Globally Harmonized System (GHS) and the Environmental Protection Agency (EPA) system. Results: The EpiAirway prediction model identified in vivo rat-based GHS Acute Inhalation Toxicity Category 1–2 and EPA Acute Inhalation Toxicity Category I–II chemicals with 100% sensitivity and specificity of 43.1% and 50.0%, for GHS and EPA acute inhalation toxicity systems, respectively. The sensitivity and specificity of the EpiAirway prediction model for identifying GHS specific target organ toxicity-single exposure (STOT-SE) Category 1 human toxicants were 75.0% and 56.5%, respectively. Corrosivity and electrophilic and oxidative reactivity appear to be the predominant mechanisms of toxicity for the most highly toxic chemicals. Conclusions: These results indicate that the EpiAirway test is a promising alternative to the currently accepted animal tests for acute inhalation toxicity. PMID:29904643

  9. Major Pesticides Are More Toxic to Human Cells Than Their Declared Active Principles

    PubMed Central

    Spiroux de Vendômois, Joël; Séralini, Gilles-Eric

    2014-01-01

    Pesticides are used throughout the world as mixtures called formulations. They contain adjuvants, which are often kept confidential and are called inerts by the manufacturing companies, plus a declared active principle, which is usually tested alone. We tested the toxicity of 9 pesticides, comparing active principles and their formulations, on three human cell lines (HepG2, HEK293, and JEG3). Glyphosate, isoproturon, fluroxypyr, pirimicarb, imidacloprid, acetamiprid, tebuconazole, epoxiconazole, and prochloraz constitute, respectively, the active principles of 3 major herbicides, 3 insecticides, and 3 fungicides. We measured mitochondrial activities, membrane degradations, and caspases 3/7 activities. Fungicides were the most toxic from concentrations 300–600 times lower than agricultural dilutions, followed by herbicides and then insecticides, with very similar profiles in all cell types. Despite its relatively benign reputation, Roundup was among the most toxic herbicides and insecticides tested. Most importantly, 8 formulations out of 9 were up to one thousand times more toxic than their active principles. Our results challenge the relevance of the acceptable daily intake for pesticides because this norm is calculated from the toxicity of the active principle alone. Chronic tests on pesticides may not reflect relevant environmental exposures if only one ingredient of these mixtures is tested alone. PMID:24719846

  10. Toxicity and biodegradability of high strength/toxic organic liquid industrial effluents and hazardous landfill leachates.

    PubMed

    Naidoo, V; du Preez, M; Rakgotho, T; Odhav, B; Buckley, C A

    2002-01-01

    Industrial effluents and leachates from hazardous landfill sites were tested for toxicity using the anaerobic toxicity assay. This test was done on several industrial effluents (brewery spent grain effluent, a chemical industry effluent, size effluent), and several hazardous landfill leachates giving vastly different toxicity results. The brewery effluent, spent grain effluent and size effluent were found to be less toxic than the chemical effluent and hazardous landfill leachate samples. The chemical industry effluent was found to be most toxic. Leachate samples from the H:h classified hazardous landfill site were found to be less toxic at high concentrations (40% (v/v)) while the H:H hazardous landfill leachate samples were found to be more toxic even at low concentrations of 4% (v/v). The 30 d biochemical methane potential tests revealed that the brewery effluent, organic spent grain effluent and size effluent were 89%, 63%, and 68% biodegradable, respectively. The leachate from Holfontein hazardous landfill site was least biodegradable (19%) while the chemical effluent and Aloes leachate were 29% and 32% biodegradable under anaerobic conditions.

  11. Potential hepatic toxicity of buprofezin at sublethal concentrations: ROS-mediated conversion of energy metabolism.

    PubMed

    Ji, Xiaotong; Ku, Tingting; Zhu, Na; Ning, Xia; Wei, Wei; Li, Guangke; Sang, Nan

    2016-12-15

    Buprofezin is known for its broad-spectrum action and environmental safety. The popularity of buprofezin has raised concerns about its potentially adverse effects on human health and risk to the environment. In this study, we first identified the liver as one of the major organs in which buprofezin accumulated, and we detected a severe oxidative stress response. Next, we demonstrated that sublethal concentrations of buprofezin promoted the conversion of energy metabolism from the aerobic tricarboxylic acid (TCA) cycle and oxidative phosphorylation to anaerobic glycolysis. Importantly, reactive oxygen species (ROS) generation partially accounted for the shunting of the energy metabolism through the buprofezin-mediated inhibition of cytochrome c oxidase activity. ROS directly perturbed the activities of several key TCA cycle enzymes, stimulated glycolysis, and indirectly disturbed the activity of the respiratory chain complex by altering mitochondrial DNA (mtDNA). These findings clarify the potential mechanisms of buprofezin toxicity and provide biomarkers for buprofezin-mediated hepatotoxicity at sublethal concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Direct toxicity assessment - Methods, evaluation, interpretation.

    PubMed

    Gruiz, Katalin; Fekete-Kertész, Ildikó; Kunglné-Nagy, Zsuzsanna; Hajdu, Csilla; Feigl, Viktória; Vaszita, Emese; Molnár, Mónika

    2016-09-01

    Direct toxicity assessment (DTA) results provide the scale of the actual adverse effect of contaminated environmental samples. DTA results are used in environmental risk management of contaminated water, soil and waste, without explicitly translating the results into chemical concentration. The end points are the same as in environmental toxicology in general, i.e. inhibition rate, decrease in the growth rate or in yield and the 'no effect' or the 'lowest effect' measurement points of the sample dilution-response curve. The measurement unit cannot be a concentration, since the contaminants and their content in the sample is unknown. Thus toxicity is expressed as the sample proportion causing a certain scale of inhibition or no inhibition. Another option for characterizing the scale of toxicity of an environmental sample is equivalencing. Toxicity equivalencing represents an interpretation tool which enables toxicity of unknown mixtures of chemicals be converted into the concentration of an equivalently toxic reference substance. Toxicity equivalencing, (i.e. expressing the toxicity of unknown contaminants as the concentration of the reference) makes DTA results better understandable for non-ecotoxicologists and other professionals educated and thinking based on the chemical model. This paper describes and discusses the role, the principles, the methodology and the interpretation of direct toxicity assessment (DTA) with the aim to contribute to the understanding of the necessity to integrate DTA results into environmental management of contaminated soil and water. The paper also introduces the benefits of the toxicity equivalency method. The use of DTA is illustrated through two case studies. The first case study focuses on DTA of treated wastewater with the aim to characterize the treatment efficacy of a biological wastewater treatment plant by frequent bioassaying. The second case study applied DTA to investigate the cover layers of two bauxite residue (red mud

  13. Toxicity of herbicides in highway runoff.

    PubMed

    Huang, Xinjiang; Fong, Stephanie; Deanovic, Linda; Young, Thomas M

    2005-09-01

    Previous field monitoring at two highway sites found highway-applied herbicides in storm water runoff at maximum concentrations ranging from 10 microg/L for glyphosate and diuron to as high as 200 microg/L for oryzalin. To determine whether these herbicides at these concentrations can cause any toxicity to aquatic organisms, a standard toxicity study was conducted. Storm water was collected along Highway 37, Sonoma County, California, USA, and the herbicides isoxaben, oryzalin, diuron, clopyralid, and glyphosate were spiked into the storm water at the highest concentrations observed during the five previous field-monitoring campaigns. Three different toxicity studies were conducted and the results showed the following: No significant reduction in reproduction or increase in mortality relative to the control for an 8-d Ceriodaphnia (water flea) toxicity test; no significant increase in mortality or decrease in biomass compared to the control during a 7-d Pimephales (fish) toxicity test; and, in a 96-h Selenastrum (algae) toxicity test, both the 10-microg/L diuron treatment and the combined 50-microg/L isoxaben plus 200-microg/L oryzalin treatment produced significant (p < 0.05) reductions in algal growth compared to the controls, although the 30-microg/L clopyralid or 10-microg/L glyphosate treatments did not exhibit any toxic effects.

  14. 40 CFR 261.24 - Toxicity characteristic.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the contaminants listed in table 1 at the concentration equal to or greater than the respective value... Hazardous Waste Number specified in Table 1 which corresponds to the toxic contaminant causing it to be hazardous. Table 1—Maximum Concentration of Contaminants for the Toxicity Characteristic EPA HW No. 1...

  15. Weathering and aging of 2,4,6-trinitrotoluene in soil increases toxicity to potworm Enchytraeus crypticus.

    PubMed

    Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Phillips, Carlton T; Kolakowski, Jan E; Kurnas, Carl W

    2005-10-01

    Energetic materials are employed in a wide range of commercial and military activities and often are released into the environment. Scientifically based ecological soil-screening levels (Eco-SSLs) are needed to identify contaminant explosive levels in soil that present an acceptable ecological risk. Insufficient information for 2,4,6-trinitrotoluene (TNT) to generate Eco-SSLs for soil invertebrates necessitated toxicity testing. We adapted the standardized Enchytraeid Reproduction Test and selected Enchytraeus crypticus for these studies. Tests were conducted in Sassafras sandy loam soil, which supports relatively high bioavailability of TNT. Weathering and aging procedures for TNT amended to test soil were incorporated into the study design to produce toxicity data that better reflect the soil exposure conditions in the field compared with toxicity in freshly amended soils. This included exposing hydrated TNT-amended soils in open glass containers in the greenhouse to alternating wetting and drying cycles. Definitive tests showed that toxicity for E. crypticus adult survival and juvenile production was increased significantly in weathered and aged soil treatments compared with toxicity in freshly amended soil based on 95% confidence intervals. The median effect concentration and 20% effective concentration for reproduction were 98 and 77 mg/kg, respectively, for TNT freshly amended into soil and 48 and 37 mg/kg, respectively, for weathered and aged TNT soil treatments. These findings of increased toxicity to E. crypticus in weathered and aged TNT soil treatments compared with exposures in freshly amended soils show that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information on ecotoxicological effects of energetic contaminants in soil.

  16. The Simplest Flowchart Stating the Mechanisms for Organic Xenobiotics-induced Toxicity: Can it Possibly be Accepted as a “Central Dogma” for Toxic Mechanisms?

    PubMed Central

    Lee, Sundong; Cho, Myung-Haing

    2014-01-01

    Xenobiotics causing a variety of toxicity in biological systems could be classified as two types, inorganic and organic chemicals. It is estimated that the organic xenobiotics are responsible for approximately 80~90% of chemical-induced toxicity in human population. In the class for toxicology, we have encountered some difficulties in explaining the mechanisms of toxicity caused especially by organic chemicals. Here, a simple flowchart was introduced for explaining the mechanism of toxicity caused by organic xenobiotics, as the central dogma of molecular biology. This flowchart, referred to as a central dogma, was described based on a view of various aspects as follows: direct-acting chemicals vs. indirect-acting chemicals, cytochrome P450-dependent vs. cytochrome P450-independent biotransformation, reactive intermediates, reactivation, toxicokinetics vs. toxicodynamics, and reversibility vs. irreversibility. Thus, the primary objective of this flowchart is to help better understanding of the organic xenobiotics-induced toxic mechanisms, providing a major pathway for toxicity occurring in biological systems. PMID:25343011

  17. Effect of concentration, exposure time, temperature, and relative humidity on the toxicity of sulfur dioxide to the spores of Botrytis cinerea

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Couey, H.M.; Uota, M.

    1961-12-01

    When spores of Botrytis cinerea are exposed to SO/sub 2/ gas, the subsequent reduction in spore germination is quantitatively proportional to the SO/sub 2/ concentration and the exposure time. The toxicity of SO/sub 2/ increases with increasing relative humidity. In an atmosphere of 96% RH, SO/sub 2/ is more than 20 times as effective as at 75% RH. The toxicity also increases about 1.5 times for each 10/sup 0/C rise in temperature between 0/sup 0/ and 30/sup 0/C. 8 references, 4 figures, 1 table.

  18. A mixture toxicity approach to predict the toxicity of Ag decorated ZnO nanomaterials.

    PubMed

    Azevedo, S L; Holz, T; Rodrigues, J; Monteiro, T; Costa, F M; Soares, A M V M; Loureiro, S

    2017-02-01

    Nanotechnology is a rising field and nanomaterials can now be found in a vast variety of products with different chemical compositions, sizes and shapes. New nanostructures combining different nanomaterials are being developed due to their enhancing characteristics when compared to nanomaterials alone. In the present study, the toxicity of a nanostructure composed by a ZnO nanomaterial with Ag nanomaterials on its surface (designated as ZnO/Ag nanostructure) was assessed using the model-organism Daphnia magna and its toxicity predicted based on the toxicity of the single components (Zn and Ag). For that ZnO and Ag nanomaterials as single components, along with its mixture prepared in the laboratory, were compared in terms of toxicity to ZnO/Ag nanostructures. Toxicity was assessed by immobilization and reproduction tests. A mixture toxicity approach was carried out using as starting point the conceptual model of Concentration Addition. The laboratory mixture of both nanomaterials showed that toxicity was dependent on the doses of ZnO and Ag used (immobilization) or presented a synergistic pattern (reproduction). The ZnO/Ag nanostructure toxicity prediction, based on the percentage of individual components, showed an increase in toxicity when compared to the expected (immobilization) and dependent on the concentration used (reproduction). This study demonstrates that the toxicity of the prepared mixture of ZnO and Ag and of the ZnO/Ag nanostructure cannot be predicted based on the toxicity of their components, highlighting the importance of taking into account the interaction between nanomaterials when assessing hazard and risk. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Aquatic Toxicity Screening of Fire Fighting Agents; 2003 Report

    DTIC Science & Technology

    2003-06-02

    Aqueous Film Forming Foam ( AFFF ), the reference toxicant. The aquatic toxicity screening consisted of an acute, static, range-finding...five concentrations of 3M Light Water Brand Aqueous Film Forming Foam ( AFFF ), the reference toxicant. The aquatic toxicity screening consisted of an...experimental foam concentrates against current Military Specification MIL-F-24385F Fire Extinguishing Agent, Aqueous Film Forming Foam

  20. Linking sub-individual and population level toxicity effects in Daphnia schoedleri (Cladocera: Anomopoda) exposed to sublethal concentrations of the pesticide α-cypermethrin.

    PubMed

    Martínez-Jerónimo, Fernando; Arzate-Cárdenas, Mario; Ortiz-Butrón, Rocío

    2013-08-01

    Synthetic pyrethroids are classified as moderately toxic to mammals and birds; nevertheless, they are highly toxic to non-target aquatic organisms such as fish and zooplankters. Chemical pollutants produce different effects in exposed organisms, ranging from biochemical to population responses. Cladocerans can modify the energy content of their offspring according to the surrounding medium as a way to improve their odds in case they have to cope with stressful conditions at birth. In this study, the effect of a synthetic pesticide on two levels of response in a Daphnia species different from those traditionally used as test organisms was evaluated. With this aim, Daphnia schoedleri neonates (<24 h) were exposed for 21 days to three sublethal concentrations of α-cypermethrin, 0.54, 5.4, and 54 ng L(-1), which correspond to 48-h EC1/100, EC1/10, and EC1, respectively. Effects were measured through a life table analysis for fecundity and survivorship. For effects on progeny, protein, carbohydrates, and lipids were determined and then transformed to caloric content. Biomarkers (BM) were expected to be the most sensitive evaluated response; nevertheless, population parameters such as survivorship and net reproductive rate (R0) were more sensitive since they presented significant differences with respect to controls at the lowest tested concentration. Neonates' caloric content varied during the reproductive period assessed and was negatively correlated to fecundity: as more neonates were born, less energy was provided by the adult females. Macromolecules concentration and caloric content values in cypermethrin-exposed adults were not different from those recorded in the control at the end of exposure time. The results herein presented suggest that stressed daphnids allocate more energy reserves to their offspring, although this strategy can vary depending on the number of reproductive events during the lifecycle, and on the toxicant's concentration. Sub

  1. Characterizing toxicity of metal-contaminated sediments from mining areas

    USGS Publications Warehouse

    Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.

    2015-01-01

    This paper reviews methods for testing the toxicity of metals associated with freshwater sediments, linking toxic effects with metal exposure and bioavailability, and developing sediment quality guidelines. The most broadly applicable approach for characterizing metal toxicity is whole-sediment toxicity testing, which attempts to simulate natural exposure conditions in the laboratory. Standard methods for whole-sediment testing can be adapted to test a wide variety of taxa. Chronic sediment tests that characterize effects on multiple endpoints (e.g., survival, growth, and reproduction) can be highly sensitive indicators of adverse effects on resident invertebrate taxa. Methods for testing of aqueous phases (pore water, overlying water, or elutriates) are used less frequently. Analysis of sediment toxicity data focuses on statistical comparisons between responses in sediments from the study area and responses in one or more uncontaminated reference sediments. For large or complex study areas, a greater number of reference sediments is recommended to reliably define the normal range of responses in uncontaminated sediments – the ‘reference envelope’. Data on metal concentrations and effects on test organisms across a gradient of contamination may allow development of concentration-response models, which estimate metal concentrations associated with specified levels of toxic effects (e.g. 20% effect concentration or EC20). Comparisons of toxic effects in laboratory tests with measures of impacts on resident benthic invertebrate communities can help document causal relationships between metal contamination and biological effects. Total or total-recoverable metal concentrations in sediments are the most common measure of metal contamination in sediments, but metal concentrations in labile sediment fractions (e.g., determined as part of selective sediment extraction protocols) may better represent metal bioavailability. Metals released by the weak-acid extraction

  2. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea

    PubMed Central

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-01-01

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  3. Indices of benthic community tolerance in contaminated Great Lakes sediments: Relations with sediment contaminant concentrations, sediment toxicity, and the sediment quality triad

    USGS Publications Warehouse

    Wildhaber, M.L.; Schmitt, C.J.

    1998-01-01

    We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls – PCBs, polycyclic aromatic hydrocarbons – PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (TL and TH, respectively); toxic units accounted for 42% TL and 53% TH of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of TL and TH indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.

  4. Exposure to toxic waste containing high concentrations of hydrogen sulphide illegally dumped in Abidjan, Côte d'Ivoire.

    PubMed

    Dongo, Kouassi; Tiembré, Issiaka; Koné, Blaise Atioumonou; Zurbrügg, Christian; Odermatt, Peter; Tanner, Marcel; Zinsstag, Jakob; Cissé, Guéladio

    2012-09-01

    On August 2006, a cargo ship illegally dumped 500 t of toxic waste containing high concentrations of hydrogen sulphide in numerous sites across Abidjan. Thousands of people became ill. Seventeen deaths were associated with toxic waste exposure. This study reports on environmental and health problems associated with the incident. A cross-sectional transect study was conducted in five waste dumping site areas. Of the households, 62.1% (n = 502) were exposed to the effects of the pollutants and 51.1% of the interviewed people (n = 2,368) in these households showed signs of poisoning. Most important symptoms were cough (37.1%), asthenia (33.1%), pruritus (29.9%) and nausea (29.1%). The health effects showed different frequencies in the five waste impact sites. Among the poisoned persons, 21.1% (n = 532) presented symptoms on the survey day (i.e., 4 months after incident). Transect sampling allowed to determine a radius of vulnerability to exposure of up to 3 km from the point of toxic waste disposal. The area of higher vulnerability is influenced by various environmental factors, such as size and severity of pollution site, duration of toxic waste pollution on the impact site and locally climatic conditions. The surveillance of effects on environment and human health is warranted to monitor the development.

  5. Toxicity of pyrolysis gases from synthetic polymers

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Soriano, J. A.; Kosola, K. L.; Kourtides, D. A.; Parker, J. A.

    1977-01-01

    The screening test method was used to investigate toxicity in polyethylene, polystyrene, polymethyl methacrylate, polyaryl sulfone, polyether sulfone, polyphenyl sulfone, and polyphenylene sulfide. Changing from a rising temperature program to a fixed temperature program resulted on shorter times to animal responses. This effect was attributed in part to more rapid generation of toxicants. The toxicants from the sulfur containing polymers appeared to act more rapidly than the toxicants from the other polymers. It was not known whether this effect was due primarily to difference in concentration or in the nature of the toxicants. The carbon monoxide concentration found did not account for the results observed with the sulfur containing polymers. Polyphenyl sulfone appeared to exhibit the least toxicity among the sulfur containing polymers evaluated under these test conditions.

  6. Effects of increasing nitrogen and phosphorus concentrations on phytoplankton community growth and toxicity during Planktothrix blooms in Sandusky Bay, Lake Erie.

    PubMed

    Davis, Timothy W; Bullerjahn, George S; Tuttle, Taylor; McKay, Robert Michael; Watson, Susan B

    2015-06-16

    Sandusky Bay experiences annual toxic cyanobacterial blooms dominated by Planktothrix agardhii/suspensa. To further understand the environmental drivers of these events, we evaluated changes in the growth response and toxicity of the Planktothrix-dominated blooms to nutrient amendments with orthophosphate (PO4) and inorganic and organic forms of dissolved nitrogen (N; ammonium (NH4), nitrate (NO3) and urea) over the bloom season (June - October). We complemented these with a metagenomic analysis of the planktonic microbial community. Our results showed that bloom growth and microcystin (MC) concentrations responded more frequently to additions of dissolved N than PO4, and that the dual addition of NH4 + PO4 and Urea + PO4 yielded the highest MC concentrations in 54% of experiments. Metagenomic analysis confirmed that P. agardhii/suspensa was the primary MC producer. The phylogenetic distribution of nifH revealed that both heterocystous cyanobacteria and heterotrophic proteobacteria had the genetic potential for N2 fixation in Sandusky Bay. These results suggest that as best management practices are developed for P reductions in Sandusky Bay, managers must be aware of the negative implications of not managing N loading into this system as N may significantly impact cyanobacterial bloom size and toxicity.

  7. The role of dissolved organic carbon concentration and composition on nickel toxicity to early life-stages of the blue mussel Mytilus edulis and purple sea urchin Strongylocentrotus purpuratus.

    PubMed

    Blewett, Tamzin A; Dow, Elissa M; Wood, Chris M; McGeer, James C; Smith, D Scott

    2018-05-24

    Nickel (Ni) emissions resulting from production and transportation raise concerns about the impact of Ni exposure to marine ecosystems. Ni bioavailability models are established for FW systems, but the influence of chemical parameters (e.g. dissolved organic carbon (DOC)) on Ni toxicity within marine systems is less well understood. To examine the effects of DOC concentration and composition on Ni toxicity, acute toxicity tests were conducted on early life-stages of blue mussels (Mytilus edulis) and sea urchin embryos (Strongylocentrotus purpuratus) in full strength sea water (32 ppt). Nine different field collected samples of water with varying concentration (up to 4.5 mg C/L) and composition of DOC were collected from the east coast of the United States. Organic matter compositional analysis included molecular fluorescence and absorbance spectroscopy. The different DOC sources had different protective effects against embryo toxicity. The control (no DOC) Ni 48 h-EC 50 for Mytilus embryos was 133 µg/L (95% confidence interval (C.I.) of 123-144 µg/L), while Strongylocentrotus embryos displayed control 96-h EC 50 values of 207 µg/L (167-247 µg/L). The most significantly protective sample had high humic acid concentrations (as determined from fluorescence spectroscopy), which yielded an EC 50 of 195 µg/L (169-222 µg/L) for Mytilus, and an EC 50 of 394 µg/L (369-419 µg/L) for S. purpuratus. Among all samples, protection was related to both DOC quantity and quality, with fluorescence-resolved humic and fulvic acid concentrations showing the strongest correlations with protection for both species. These data suggest that DOC is protective against Ni toxicity in M. edulis and S. purpuratus, and that accounting for a DOC quality factor will improve predictive toxicity models such as the biotic ligand model. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Determination of Trace Metals, Moisture, pH and Assessment of Potential Toxicity of Selected Smokeless Tobacco Products

    PubMed Central

    Prabhakar, V.; Jayakrishnan, G.; Nair, S. V.; Ranganathan, B.

    2013-01-01

    The characterization and classification of smokeless tobacco products has been a continuously evolving process. This is based on a number of different parameters like nicotine content, moisture content, amount of heavy metals, pH, and in vitro cytotoxicity assays. Their contexts often vary between countries, research institutions, and legal requirements. The categorisation of these products is quite challenging due to the diffused sample sizes, diverse array of branded products on offer, and the absence of a centralized manufacturing facility. This study aims at a systematic classification of 10 smokeless tobacco product samples from the retail market based on their potential toxicity upon long-term use. The estimation of potential toxicity follows a well-established method that employs the concentration of toxic metals in the different samples. The potential toxicity as well as heavy metal concentrations of the smokeless tobacco products analysed was found to be much higher than acceptable limits. For instance, the levels of lead, cadmium, copper and zinc of 2.5, 1, 4 and 23 ppm, respectively, are well above their recommended limits. The results from the study indicate that chronic use of smokeless tobacco products is a significant health risk, especially in the vulnerable population. Further studies of this nature will help establish a toxicological fingerprint on the diverse class of products that floods the market now. PMID:24082341

  9. Concentrations and geographical variations of selected toxic elements in meat from semi-domesticated reindeer (Rangifer tarandus tarandus L.) in mid- and northern Norway: evaluation of risk assessment.

    PubMed

    Hassan, Ammar Ali; Brustad, Magritt; Sandanger, Torkjel M

    2012-05-01

    Meat samples (n = 100) from semi-domesticated reindeer (Rangifer tarandus tarandus L.) were randomly collected from 10 grazing districts distributed over four Norwegian counties in 2008 and 2009. The main aim was to study concentrations and geographical variations in selected toxic elements; cadmium (Cd), lead (Pb), arsenic (As), copper (Cu), nickel (Ni) and vanadium (V) in order to assess the risk associated with reindeer meat consumption. Sample solutions were analysed using an inductively coupled plasma high resolution mass spectrometer (ICP-HRMS), whereas analysis of variance (ANOVA) was used for statistical analyses. Geographical variations in element concentrations were revealed, with As and Cd demonstrating the largest geographical differences. No clear geographical gradient was observed except for the east-west downward gradient for As. The As concentrations were highest in the vicinity of the Russian border, and only Cd was shown to increase with age (p < 0.05). Sex had no significant effect on the concentration of the studied elements. The concentrations of all the studied elements in reindeer meat were generally low and considerably below the maximum levels (ML) available for toxic elements set by the European Commission (EC). Thus, reindeer meat is not likely to be a significant contributor to the human body burden of toxic elements.

  10. Concentrations and Geographical Variations of Selected Toxic Elements in Meat from Semi-Domesticated Reindeer (Rangifer tarandus tarandus L.) in Mid- and Northern Norway: Evaluation of Risk Assessment

    PubMed Central

    Hassan, Ammar Ali; Brustad, Magritt; Sandanger, Torkjel M.

    2012-01-01

    Meat samples (n = 100) from semi-domesticated reindeer (Rangifer tarandus tarandus L.) were randomly collected from 10 grazing districts distributed over four Norwegian counties in 2008 and 2009. The main aim was to study concentrations and geographical variations in selected toxic elements; cadmium (Cd), lead (Pb), arsenic (As), copper (Cu), nickel (Ni) and vanadium (V) in order to assess the risk associated with reindeer meat consumption. Sample solutions were analysed using an inductively coupled plasma high resolution mass spectrometer (ICP-HRMS), whereas analysis of variance (ANOVA) was used for statistical analyses. Geographical variations in element concentrations were revealed, with As and Cd demonstrating the largest geographical differences. No clear geographical gradient was observed except for the east-west downward gradient for As. The As concentrations were highest in the vicinity of the Russian border, and only Cd was shown to increase with age (p < 0.05). Sex had no significant effect on the concentration of the studied elements. The concentrations of all the studied elements in reindeer meat were generally low and considerably below the maximum levels (ML) available for toxic elements set by the European Commission (EC). Thus, reindeer meat is not likely to be a significant contributor to the human body burden of toxic elements. PMID:22754467

  11. Toxic and trace metal concentrations in liver and kidney of dogs: influence of diet, sex, age, and pathological lesions.

    PubMed

    Löpez-Alonso, Marta; Miranda, Marta; García-Partida, Paulino; Mendez, Adriana; Castillo, Cristina; Benedito, José Luis

    2007-05-01

    The aim of this study was to provide data on the main toxic and trace metals in the liver and kidney of domestic dogs in Galicia, NW Spain and to evaluate the influence of diet, sex, age, and pathological lesions on metal accumulation. Samples of the liver and kidney from 77 male and female dogs, aged between 6 mo and 18 yr, were collected during ordinary necropsy. Samples were acid-digested and metal concentrations determined by inductively coupled plasma (ICP)-mass spectrometry and ICP-atomic emission spectrometry. Mean toxic metal concentrations (geometric means for liver and kidney respectively) were 11.5 and 15.8 microg/kg wet weight for As, 56.3 and 166 microg/kg for Cd, 32.7 and 51.9 microg/kg for Hg, and 60.1 and 23.6 microg/kg for Pb. For the trace metals, these concentrations were respectively 16.3 and 21.0 microg/kg for Co, 57.6 and 43.9 microg/kg for Cr, 42.1 and 5.95 mg/kg for Cu, 394 mg/kg and 95.7 mg/kg for Fe, 2.39 and 0.956 mg/kg for Mn, 0.522 and 0.357 mg/kg for Mo, 23.8 and 26.8 microg/kg for Ni, 0.686 and 1.39 mg/kg for Se, and 46.7 and 26.0 mg/kg for Zn. Cd concentrations in the kidney significantly increased with age, and Co concentrations in the liver and kidney significantly decreased with age. Hepatic Pb concentrations were significantly higher in growing (<1 yr) and old (>10 yr) dogs. Animals with pathological lesions showed significantly higher Co and lower Mn and Zn concentrations in liver than animals without macroscopic abnormalities. Dogs that received commercial diets in general showed low variability in hepatic mineral status compared to animals that receive homemade feeds or a mixture of commercial and homemade feeds.

  12. Toxicity profiles and solvent-toxicant interference in the planarian Schmidtea mediterranea after dimethylsulfoxide (DMSO) exposure.

    PubMed

    Stevens, An-Sofie; Pirotte, Nicky; Plusquin, Michelle; Willems, Maxime; Neyens, Thomas; Artois, Tom; Smeets, Karen

    2015-03-01

    To investigate hydrophobic test compounds in toxicological studies, solvents like dimethylsulfoxide (DMSO) are inevitable. However, using these solvents, the interpretation of test compound-induced responses can be biased. DMSO concentration guidelines are available, but are mostly based on acute exposures involving one specific toxicity endpoint. Hence, to avoid solvent-toxicant interference, we use multiple chronic test endpoints for additional interpretation of DMSO concentrations and propose a statistical model to assess possible synergistic, antagonistic or additive effects of test compounds and their solvents. In this study, the effects of both short- (1 day) and long-term (2 weeks) exposures to low DMSO concentrations (up to 1000 µl l(-1) ) were studied in the planarian Schmidtea mediterranea. We measured different biological levels in both fully developed and developing animals. In a long-term exposure set-up, a concentration of 500 µl l(-1) DMSO interfered with processes on different biological levels, e.g. behaviour, stem cell proliferation and gene expression profiles. After short exposure times, 500 µl l(-1) DMSO only affected motility, whereas the most significant changes on different parameters were observed at a concentration of 1000 µl l(-1) DMSO. As small sensitivity differences exist between biological levels and developmental stages, we advise the use of this solvent in concentrations below 500 µl l(-1) in this organism. In the second part of our study, we propose a statistical approach to account for solvent-toxicant interactions and discuss full-scale solvent toxicity studies. In conclusion, we reassessed DMSO concentration limits for different experimental endpoints in the planarian S. mediterranea. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Analysis of the Toxic Element Concentrations in the Mesozoic Siliceous Rocks in Terms of the Raw Material Importance

    NASA Astrophysics Data System (ADS)

    Pękala, Agnieszka

    2017-10-01

    As part of an integrated system of environmental protection at every stage of the product life cycle such as: raw material extraction, its transportation and processing as well the subsequent use and development is required to carry out actions towards reducing or completely eliminating products that contain harmful substances to the environment. The purpose of the presented paper is an analysis of the toxic element concentrations in the extracted siliceous minerals at the initial stage of the raw material recognition. The research material is constituted by rocks collected from the Mesozoic bedrock from the Bełchatów lignite deposit. A group of the studied rocks is represented by diatomites, gaizes, opoka-rocks and light opoka-rocks, enriched with minerals from the group of SiO2. Most of the recognized petrographic sediments have a real possibility of potential applications in the building material industry, but it needs to carry out a detailed and thorough research. The studies of the chemical composition were determined by atomic absorption spectroscopy (AAS) using Philips PU 9100Xi Camera SX-100 spectrometer and an atomic emission spectroscopy with inductively coupled plasma (ICP AES) using PLASMA 40 spectrometer. There were carried out a chemical analyses and determined the content of some toxic elements: Pb, Cr, Cd, Ni, Zn, Cu, Co, As, Sr, Ba, Zr. in the studied sedimentary rocks. The analysis of the results draws attention to the high content of cadmium in the case of the studied sediments. The concentration of this element in the described rocks is an average of 0.22 mg/kg -the diatomites, 0.05 mg/kg -the gaizes, 0.4 mg/kg -the opoka-rocks, 2.23 mg/kg -the light opoka-rocks. It was moreover registered varied concentration of arsenic in diatomites, that is formed in the range of 0.05 - 9.6 mg/kg, an average of 6.3 mg/kg. The content of the other designated elements with toxic properties in the analysed groups of rocks does not exceed the limit values. An

  14. Heavy metal toxicity to bacteria - are the existing growth media accurate enough to determine heavy metal toxicity?

    PubMed

    Rathnayake, I V N; Megharaj, Mallavarapu; Krishnamurti, G S R; Bolan, Nanthi S; Naidu, Ravi

    2013-01-01

    A new minimal medium was formulated considering the limitations of the existing media for testing heavy metal sensitivity to bacteria. Toxicity of cadmium and copper to three bacteria was investigated in the new medium and compared with three other media commonly used to study the effect of the toxic metals. Based on speciation data arrived at using ion-selective electrodes, the available free-metal concentration in solution was highest in the MES-buffered medium. This finding was strongly supported by the estimated EC(50) values for the metals tested based on the toxicity bioassays. The free-ionic cadmium and copper concentrations in the medium provide more accurate determination of metal concentrations that affects the bacteria, than with most of other existing media. This will avoid doubts on other media and misleading conclusions relevant to the toxicity of heavy metals to bacteria and provides a better option for the study of metal-bacteria interactions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Development of a general baseline toxicity QSAR model for the fish embryo acute toxicity test.

    PubMed

    Klüver, Nils; Vogs, Carolina; Altenburger, Rolf; Escher, Beate I; Scholz, Stefan

    2016-12-01

    Fish embryos have become a popular model in ecotoxicology and toxicology. The fish embryo acute toxicity test (FET) with the zebrafish embryo was recently adopted by the OECD as technical guideline TG 236 and a large database of concentrations causing 50% lethality (LC 50 ) is available in the literature. Quantitative Structure-Activity Relationships (QSARs) of baseline toxicity (also called narcosis) are helpful to estimate the minimum toxicity of chemicals to be tested and to identify excess toxicity in existing data sets. Here, we analyzed an existing fish embryo toxicity database and established a QSAR for fish embryo LC 50 using chemicals that were independently classified to act according to the non-specific mode of action of baseline toxicity. The octanol-water partition coefficient K ow is commonly applied to discriminate between non-polar and polar narcotics. Replacing the K ow by the liposome-water partition coefficient K lipw yielded a common QSAR for polar and non-polar baseline toxicants. This developed baseline toxicity QSAR was applied to compare the final mode of action (MOA) assignment of 132 chemicals. Further, we included the analysis of internal lethal concentration (ILC 50 ) and chemical activity (La 50 ) as complementary approaches to evaluate the robustness of the FET baseline toxicity. The analysis of the FET dataset revealed that specifically acting and reactive chemicals converged towards the baseline toxicity QSAR with increasing hydrophobicity. The developed FET baseline toxicity QSAR can be used to identify specifically acting or reactive compounds by determination of the toxic ratio and in combination with appropriate endpoints to infer the MOA for chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. The influence of magnesium supplementation on concentrations of chosen bioelements and toxic metals in adult human hair. Magnesium and chosen bioelements in hair.

    PubMed

    Kozielec, Tadeusz; Sałacka, Anna; Karakiewicz, Beata

    2004-09-01

    The basic functions of bioelements in biological systems is widely known. Depletion of bioelements and excess of toxic elements lead to impairment of metabolism in the living organism. The existence of magnesium deficiencies in the adult and pediatric populations may cause increased accumulation of toxic metals including lead and cadmium. Prevention of adverse effects of toxic metals may include supplementation with some bioelements and vitamins. The aim of this study was to evaluate the influence of magnesium supplementation on concentrations of chosen bioelements and toxic metals in hair in the adult human population. The research was performed on 124 individuals (53 males and 71 females aged 19-72 years), inhabitants of the city of Szczecin. The concentrations of magnesium, zinc, copper, lead and cadmium were studied in hair. Measurements were performed using the inversion volt-amperometry method with application of an EDD-Tribo PC ETP volt-amperometer. Finally, the supplementation study enrolled 65 individuals with an increased concentration of lead. The studied individuals were divided into two groups: one treated group that enrolled 50 patients who were supplemented with magnesium and the control group that enrolled 15 persons receiving placebo. Finally, supplementation was completed by 32 individuals from the treated group and 10 individuals from the control group. Supplementation was performed using Slow-Mag-B6 preparation at the total daily dose of five tablets divided into 2-3 doses. One tablet contains 535 mg of magnesium chloride i.e. 64 mg of magnesium ions (5.26 mEgMg2) and 5 mg of vitamin B6. Supplementation was performed for a period of 3 months. The remaining individuals did not complete the supplementation due to various reasons; however, none of them resulted from the poor tolerance of the preparation or its adverse events. The results achieved underwent statistical analysis. The results of the study revealed a positive influence of

  17. Development of a toxicity identification evaluation procedure for characterizing metal toxicity in marine sediments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Burgess, R.M.; Cantwell, M.G.; Pelletier, M.C.

    2000-04-01

    A multiagency effort is underway to develop whole sediment toxicity identification evaluation (TIE) methods. Whole sediment TIE methods will be critical tools for characterizing toxicity at hazardous waste sites and in the conduct of environmental risk assessments. The research approach is based on the predominance of three classes of toxicants in sediments: ammonia, nonpolar organic chemicals, and metals. Here the authors describe a procedure for characterizing acute toxicity caused by metals in whole marine sediments. The procedure involves adding a chelating resin to sediments, resulting in the sequestration of bioavailable metal while not stressing testing organisms. Within the testing chambers,more » the presence of resin resulted in statistically significant reductions in the overlying and interstitial water concentrations of five metals (cadmium, copper, nickel, lead, and zinc) generally by factors of 40 and 200. Toxicity to both the amphipod Ampelisca abdita and mysid Americamysis bahia (formerly Mysidopsis bahia) of sediments spiked with the five metals was decreased by approximately a factor of four when resin was present. While very effective at reducing the concentrations and toxicity of metals, the resin has only minor ameliorative effects on the toxicity of ammonia and a representative nonpolar toxicant (Endosulfan). Resin and accumulated metal were easily isolated from the testing system following exposures allowing for the initiation of phase II TIE (identification) procedures. This procedure using the addition of a chelating resin provides an approach for determining the importance of metals to the toxicity of marine sediments. Work is continuing to validate the method with environmentally contaminated sediments.« less

  18. VORICONAZOLE TOXICITY IN MULTIPLE PENGUIN SPECIES.

    PubMed

    Hyatt, Michael W; Georoff, Timothy A; Nollens, Hendrik H; Wells, Rebecca L; Clauss, Tonya M; Ialeggio, Donna M; Harms, Craig A; Wack, Allison N

    2015-12-01

    Aspergillosis is a common respiratory fungal disease in penguins managed under human care. Triazole antifungal drugs, including itraconazole, are most commonly used for treatment; however, itraconazole treatment failures from drug resistance are becoming more common, requiring newer treatment options. Voriconazole, a newer triazole, is being used more often. Until recently, no voriconazole pharmacokinetic studies had been performed in penguins, leading to empiric dosing based on other avian studies. This has led to increased anecdotal reporting of apparent voriconazole toxicity in penguins. This report describes 18 probable and 6 suspected cases of voriconazole toxicity in six penguin species from nine institutions: 12 African penguins (Spheniscus demersus), 5 Humboldt penguins (Spheniscus humboldti), 3 Magellanic penguins (Spheniscus magellanicus), 2 gentoo penguins (Pygoscelis papua papua), 1 macaroni penguin (Eudyptes chrysolophus), and 1 emperor penguin (Aptenodytes forsteri). Observed clinical signs of toxicity included anorexia, lethargy, weakness, ataxia, paresis, apparent vision changes, seizure-like activity, and generalized seizures. Similar signs of toxicity have also been reported in humans, in whom voriconazole therapeutic plasma concentration for Aspergillus spp. infections is 2-6 μg/ml. Plasma voriconazole concentrations were measured in 18 samples from penguins showing clinical signs suggestive of voriconazole toxicity. The concentrations ranged from 8.12 to 64.17 μg/ml, with penguins having plasma concentrations above 30 μg/ml exhibiting moderate to severe neurologic signs, including ataxia, paresis, and seizures. These concentrations were well above those known to result in central nervous system toxicity, including encephalopathy, in humans. This case series highlights the importance of species-specific dosing of voriconazole in penguins and plasma therapeutic drug monitoring. Further investigation, including pharmacokinetic studies, is

  19. Acute toxicity of leachates of tire wear material to Daphnia magna--variability and toxic components.

    PubMed

    Wik, Anna; Dave, Göran

    2006-09-01

    Large amounts of tire rubber are deposited along the roads due to tread wear. Several compounds may leach from the rubber and cause toxicity to aquatic organisms. To investigate the toxic effects of tire wear material from different tires, rubber was abraded from the treads of twenty-five tires. Leachates were prepared by allowing the rubber to equilibrate with dilution water at 44 degrees C for 72 h. Then the rubber was filtered from the leachates, and test organisms (Daphnia magna) were added. Forty-eight hour EC50s ranged from 0.5 to >10.0 g l(-1). The toxicity identification evaluation (TIE) indicated that non-polar organic compounds caused most of the toxicity. UV exposure of the filtered tire leachates caused no significant increase in toxicity. However, when tested as unfiltered leachates (the rubber was not filtered from the leachates before addition of D. magna) photo-enhanced toxicity was considerable for some tires, which means that test procedures are important when testing tire leachates for aquatic (photo) toxicity. The acute toxicity of tire wear for Daphnia magna was found to be <40 times a predicted environmental concentration based on reports on the concentration of a tire component found in environmental samples, which emphasizes the need for a more extensive risk assessment of tire wear for the environment.

  20. STATISTICAL APPROACH TO PREDICTING CHRONIC TOXICITY OF CHEMICALS TO FISHES FROM ACUTE TOXICITY TEST DATA

    EPA Science Inventory

    A comprehensive approach to predicting chronic toxicity from cute toxicity data was developed in which simultaneous onsideration is given to concentration, degree of response, and ime course of effect. onsistent endpoint (lethality) and degree of response (0 percent) were used to...

  1. Assessment of environmental risks from toxic and nontoxic stressors; a proposed concept for a risk-based management tool for offshore drilling discharges.

    PubMed

    Smit, Mathijs G D; Jak, Robbert G; Rye, Henrik; Frost, Tone Karin; Singsaas, Ivar; Karman, Chris C

    2008-04-01

    In order to improve the ecological status of aquatic systems, both toxic (e.g., chemical) and nontoxic stressors (e.g., suspended particles) should be evaluated. This paper describes an approach to environmental risk assessment of drilling discharges to the sea. These discharges might lead to concentrations of toxic compounds and suspended clay particles in the water compartment and concentrations of toxic compounds, burial of biota, change in sediment structure, and oxygen depletion in marine sediments. The main challenges were to apply existing protocols for environmental risk assessment to nontoxic stressors and to combine risks arising from exposure to these stressors with risk from chemical exposure. The defined approach is based on species sensitivity distributions (SSDs). In addition, precautionary principles from the EU-Technical Guidance Document were incorporated to assure that the method is acceptable in a regulatory context. For all stressors a protocol was defined to construct an SSD for no observed effect concentrations (or levels; NOEC(L)-SSD) to allow for the calculation of the potentially affected fraction of species from predicted exposures. Depending on the availability of data, a NOEC-SSD for toxicants can either be directly based on available NOECs or constructed from the predicted no effect concentration and the variation in sensitivity among species. For nontoxic stressors a NOEL-SSD can be extrapolated from an SSD based on effect or field data. Potentially affected fractions of species at predicted exposures are combined into an overall risk estimate. The developed approach facilitates environmental management of drilling discharges and can be applied to define risk-mitigating measures for both toxic and nontoxic stress.

  2. Sediment toxicity in Savannah Harbor

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.

    1995-01-01

    Savannah Harbor, located near the mouth of the Savannah River, Georgia and South Carolina, is impacted by industrial and municipal effluents. Potential release of contaminants stored in harbor sediments through dredging and shipping operations requires that contaminated areas be identified for proper management of the system and protection of wildlife resources. During 1991, Hyalella azteca were exposed in 10-d static-renewal toxicity tests to pore-water and solid-phase sediment samples collected from 26 sites within Savannah Harbor. Pore-water toxicity was more pronounced than that for solidphase sediment. Toxicity and reduced leaf consumption demonstrated impaired sediment quality at specific sites within Savannah Harbor and Back River. Factors responsible for the decreased sediment quality were ammonia, alkalinity, and metal concentrations (cadmium, chromium, lead, molybdenum, and nickel). Elevated concentrations of metals and toxicities in Back River sediments indicated impacts from adjacent dredge-spoil areas.

  3. Fluvial biofilms: A pertinent tool to assess beta-blockers toxicity.

    PubMed

    Bonnineau, Chloé; Guasch, Helena; Proia, Lorenzo; Ricart, Marta; Geiszinger, Anita; Romaní, Anna M; Sabater, Sergi

    2010-02-18

    Among increasingly used pharmaceutical products, beta-blockers have been commonly reported at low concentrations in rivers and littoral waters of Europe and North America. Little is known about the toxicity of these chemicals in freshwater ecosystems while their presence may lead to chronic pollution. Hence, in this study the acute toxicity of 3 beta-blockers: metoprolol, propranolol and atenolol on fluvial biofilms was assessed by using several biomarkers. Some were indicative of potential alterations in biofilm algae (photosynthetic efficiency), and others in biofilm bacteria (peptidase activity, bacterial mortality). Propranolol was the most toxic beta-blocker, mostly affecting the algal photosynthetic process. The exposure to 531microg/L of propranolol caused 85% of inhibition of photosynthesis after 24h. Metoprolol was particularly toxic for bacteria. Though estimated No-Effect Concentrations (NEC) were similar to environmental concentrations, higher concentrations of the toxic (503microg/L metoprolol) caused an increase of 50% in bacterial mortality. Atenolol was the least toxic of the three tested beta-blockers. Effects superior to 50% were only observed at very high concentration (707mg/L). Higher toxicity of metoprolol and propranolol might be due to better absorption within biofilms of these two chemicals. Since beta-blockers are mainly found in mixtures in rivers, their differential toxicity could have potential relevant consequences on the interactions between algae and bacteria within river biofilms. 2009 Elsevier B.V. All rights reserved.

  4. Testing the toxicity of metals, phenol, effluents, and receiving waters by root elongation in Lactuca sativa L.

    PubMed

    Lyu, Jie; Park, Jihae; Kumar Pandey, Lalit; Choi, Soyeon; Lee, Hojun; De Saeger, Jonas; Depuydt, Stephen; Han, Taejun

    2018-03-01

    Phytotoxicity tests using higher plants are among the most simple, sensitive, and cost-effective of the methods available for ecotoxicity testing. In the present study, a hydroponic-based phytotoxicity test using seeds of Lactuca sativa was used to evaluate the water quality of receiving waters and effluents near two industrial sites (Soyo and Daejon) in Korea with respect to the toxicity of 10 metals (As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, Zn) and phenol, and of the receiving waters and effluents themselves. First, the L. sativa hydroponic bioassay was used to determine whether the receiving water or effluents were toxic; then, the responsible toxicant was identified. The results obtained with the L. sativa bioassay ranked the EC 50 toxicities of the investigated metal ions and phenol as: Cd > Ni > Cu > Zn > Hg > phenol > As > Mn > Cr > Pb > Fe. We found that Zn was the toxicant principally responsible for toxicity in Daejeon effluents. The Daejeon field effluent had a higher Zn concentration than permitted by the effluent discharge criteria of the Ministry of Environment of Korea. Our conclusion on the importance of Zn toxicity was supported by the results of the L. sativa hydroponic assay, which showed that the concentration of Zn required to inhibit root elongation in L. sativa by 50% (EC 50 ) was higher in the Daejeon field effluent than that of pure Zn. More importantly, we proved that the L. sativa hydroponic test method can be applied not only as an alternative tool for determining whether a given waste is acceptable for discharge into public water bodies, but also as an alternative method for measuring the safety of aquatic environments using EC 20 values, with respect to the water pollutants investigated (i.e., Cd, Cr, Cu, Pb, Mn, Hg, Ni, Zn, and phenol). Copyright © 2017. Published by Elsevier Inc.

  5. Comparative chronic toxicity of imidacloprid, clothianidin, and thiamethoxam to Chironomus dilutus and estimation of toxic equivalency factors.

    PubMed

    Cavallaro, Michael C; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

    2017-02-01

    Nontarget aquatic insects are susceptible to chronic neonicotinoid insecticide exposure during the early stages of development from repeated runoff events and prolonged persistence of these chemicals. Investigations on the chronic toxicity of neonicotinoids to aquatic invertebrates have been limited to a few species and under different laboratory conditions that often preclude direct comparisons of the relative toxicity of different compounds. In the present study, full life-cycle toxicity tests using Chironomus dilutus were performed to compare the toxicity of 3 commonly used neonicotinoids: imidacloprid, clothianidin, and thiamethoxam. Test conditions followed a static-renewal exposure protocol in which lethal and sublethal endpoints were assessed on days 14 and 40. Reduced emergence success, advanced emergence timing, and male-biased sex ratios were sensitive responses to low-level neonicotinoid exposure. The 14-d median lethal concentrations for imidacloprid, clothianidin, and thiamethoxam were 1.52 μg/L, 2.41 μg/L, and 23.60 μg/L, respectively. The 40-d median effect concentrations (emergence) for imidacloprid, clothianidin, and thiamethoxam were 0.39 μg/L, 0.28 μg/L, and 4.13 μg/L, respectively. Toxic equivalence relative to imidacloprid was estimated through a 3-point response average of equivalencies calculated at 20%, 50%, and 90% lethal and effect concentrations. Relative to imidacloprid (toxic equivalency factor [TEF] = 1.0), chronic (lethality) 14-d TEFs for clothianidin and thiamethoxam were 1.05 and 0.14, respectively, and chronic (emergence inhibition) 40-d TEFs were 1.62 and 0.11, respectively. These population-relevant endpoints and TEFs suggest that imidacloprid and clothianidin exert comparable chronic toxicity to C. dilutus, whereas thiamethoxam induced comparable effects only at concentrations an order of magnitude higher. However, the authors caution that under field conditions, thiamethoxam readily degrades to

  6. Synergistic effect of piperonyl butoxide on acute toxicity of pyrethrins to Hyalella azteca.

    PubMed

    Giddings, Jeffrey; Gagne, James; Sharp, Janice

    2016-08-01

    A series of acute toxicity tests with the amphipod Hyalella azteca was performed to quantify the synergistic effect of piperonyl butoxide (PBO) on pyrethrin toxicity. Concentrations of PBO <4 µg/L caused no toxicity enhancement, whereas toxicity increased with PBO concentrations between 4 µg/L and 15 µg/L. Additive toxicity calculations showed that true synergism accounted for an increase in pyrethrin toxicity (decrease in median lethal concentration) of 1.4-fold to 1.6-fold and varied only slightly between 4 µg/L and 15 µg/L PBO, whereas direct toxicity of PBO accounted for an additional increase in mixture toxicity (up to 3.2-fold) that was proportional to PBO concentration. The results can be used to assess the risk of measured or predicted co-occurring concentrations of PBO and pyrethrins in surface waters. Environ Toxicol Chem 2016;35:2111-2116. © 2016 SETAC. © 2016 SETAC.

  7. PREDICTING CHRONIC TOXICITY OF CHEMICALS TO FISHES FROM ACUTE TOXICITY TEST DATA: CONCEPT AND LINEAR REGRESSION

    EPA Science Inventory

    A comprehensive approach to predicting chronic toxicity from acute.toxicity data was developed in which simultaneous consideration is given to concentration, degree of response, and time course of effect. onsistent endpoint (lethality) and degree of response (O%) were used to com...

  8. Occurrence and risk assessment of potentially toxic elements and typical organic pollutants in contaminated rural soils.

    PubMed

    Xu, Yongfeng; Dai, Shixiang; Meng, Ke; Wang, Yuting; Ren, Wenjie; Zhao, Ling; Christie, Peter; Teng, Ying

    2018-07-15

    The residual levels and risk assessment of several potentially toxic elements (PTEs), phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in rural soils near different types of pollution sources in Tianjin, China, were studied. The soils were found to be polluted to different extents with PTEs, PAEs and PAHs from different pollution sources. The soil concentrations of chromium (Cr), nickel (Ni), di-n-butyl phthalate (DnBP), acenaphthylene (Any) and acenaphthene (Ane) were higher than their corresponding regulatory reference limits. The health risk assessment model used to calculate human exposure indicates that both non-carcinogenic and carcinogenic risks from selected pollutants were generally acceptable or close to acceptable. Different types of pollution sources and soil physicochemical properties substantially affected the soil residual concentrations of and risks from these pollutants. PTEs in soils collected from agricultural lands around industrial and residential areas and organic pollutants (PAEs and PAHs) in soils collected from agricultural areas around livestock breeding were higher than those from other types of pollution sources and merit long-term monitoring. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Polychlorinated biphenyl toxicity to Japanese quail as related to degree of chlorination

    USGS Publications Warehouse

    Hill, E.F.; Heath, R.G.; Spann, J.W.; Williams, J.D.

    1974-01-01

    To learn if the percentage of chlorine in a mixture of polychlorinated biphenyls (PCB's) alone determines toxicity, Japanese quail were fed diets containing Aroelor 1248, 1254, or 1260 at levels that added equal amounts of chlorine to the feed. The experiment comprised two consecutive 5-day periods; three sublethal concentrations of chlorine were evaluated during the first period and three lethal concentrations during the second period. Evaluations utilized comparisons of mortality, time to death, weight change, and food consumption. Sublethal concentrations produced no detectable effects. Lethal concentrations with equal Chlorine showed Aroelor 1248 to be less toxic at the highest chlorine concentrations, but at lower concentrations Aroelor 1254 was more toxic than Aroclor 1260. Although chlorine percentage of a PCB is positively correlated with its avian toxicity, PCB toxicity is apparently not simply a function of chlorination.

  10. Fluoroacetate-mediated toxicity of fluorinated ethanes.

    PubMed

    Keller, D A; Roe, D C; Lieder, P H

    1996-04-01

    A series of 1-(di)halo-2-fluoroethanes reported in the literature to be nontoxic or of low toxicity were found to be highly toxic by the inhalation route. Experiments were performed that showed the compounds, 1,2-difluoroethane, 1-chloro-2-fluoroethane, 1-chloro-1,2-difluoroethane, and 1-bromo-2-fluoroethane to be highly toxic to rats upon inhalation for 4 hr. All four compounds had 4-hr approximate lethal concentrations of < or = 100 ppm in rats. In contrast, 1,1-difluoroethane (commonly referred to as HFC-152a) has very low acute toxicity with a 4-hr LC50 of > 400,000 ppm in rats. Rats exposed to the selected toxic fluoroethanes showed clinical signs of fluoroacetate toxicity (lethargy, hunched posture, convulsions). 1,2-Difluoroethane, 1-chloro-2-fluoroethane, 1-chloro-1,2-difluoroethane, and 1-bromo-2-fluoroethane were shown to increase concentrations of citrate in serum and heart tissue, a hallmark of fluoroacetate intoxication. 19F NMR analysis confirmed that fluoroacetate was present in the urine of rats exposed to each toxic compound. Fluorocitrate, a condensation product of fluoroacetate and oxaloacetate, was identified in the kidney of rats exposed to 1,2-difluoroethane. There was a concentration-related elevation of serum and heart citrate in rats exposed to 0-1000 ppm 1,2-fluoroethane. Serum citrate was increased up to 5-fold and heart citrate was increased up to 11-fold over control citrate levels. Metabolism of 1,2-difluoroethane by cytochrome P450 (most likely CYP2E1) is suspected because pretreatment of rats or mice with SKF-525F, disulfiram, or dimethyl sulfoxide prevented or delayed the toxicity observed in rats not pretreated. Experimental evidence indicates that the metabolism of the toxic fluoroethanes is initiated at the carbon-hydrogen bond, with metabolism to fluoroacetate via an aldehyde or an acyl fluoride. The results of these studies show that 1-(di)halo-2-fluoroethanes are highly toxic to rats and should be considered a hazard to humans

  11. High exposure to zidovudine during the first 2 weeks of life and concentration-toxicity relationships.

    PubMed

    Hirt, Déborah; Warszawski, Josiane; Firtion, Ghislaine; Giraud, Carole; Chappuy, Hélène; Lechenadec, Jérôme; Benaboud, Sihem; Urien, Saïk; Blanche, Stéphane; Tréluyer, Jean-Marc

    2013-08-15

    The aims of the study were in a large group of neonates to identify the relative effect of bodyweight, postnatal age, and gestational age on zidovudine (ZDV) pharmacokinetics; to link concentrations with lactate and hemoglobin levels; and to find the more appropriate neonatal ZDV dose. In 484 neonates aged 3-30 days, born to HIV-infected mothers, 767 ZDV and 417 ZDV glucuronide concentrations were collected. Using a population approach, ZDV clearance per kilogram increased with postnatal age but not with gestational age. High neonatal exposures were found as follows: 14,025 ng/mL·h the first week and 6528 ng/mL·h the second week in comparison to 3000 ng/mL·h in adults. At month 1, median lactate level was 2.8 mmol/L (60%, ≥2.5 mmol/L) and median hemoglobin was 10.1 g/dL (90%, <12 g/dL). ZDV trough concentrations at first sampling (days 3-7) or at last sampling (day 20 ± 10) were significantly negatively correlated to hemoglobin at months 1, 3, and 6 (P < 0.02). ZDV maximal or trough concentrations at days 3-7 and at day 20 ± 10 were significantly positively correlated to lactate levels at months 3 and 6, respectively. To obtain an exposure comparable to adults, which should reduce neonatal toxicity, doses should to be decreased during the first 2 weeks of life.

  12. Acceptance of sugar reduction in flavored yogurt.

    PubMed

    Chollet, M; Gille, D; Schmid, A; Walther, B; Piccinali, P

    2013-09-01

    To investigate what level of sugar reduction is accepted in flavored yogurt, we conducted a hedonic test focusing on the degree of liking of the products and on optimal sweetness and aroma levels. For both flavorings (strawberry and coffee), consumers preferred yogurt containing 10% added sugar. However, yogurt containing 7% added sugar was also acceptable. On the just-about-right scale, yogurt containing 10% sugar was more often described as too sweet compared with yogurt containing 7% sugar. On the other hand, the sweetness and aroma intensity for yogurt containing 5% sugar was judged as too low. A second test was conducted to determine the effect of flavoring concentration on the acceptance of yogurt containing 7% sugar. Yogurts containing the highest concentrations of flavoring (11% strawberry, 0.75% coffee) were less appreciated. Additionally, the largest percentage of consumers perceived these yogurts as "not sweet enough." These results indicate that consumers would accept flavored yogurts with 7% added sugar instead of 10%, but 5% sugar would be too low. Additionally, an increase in flavor concentration is undesirable for yogurt containing 7% added sugar. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Predicting the toxicity of metal mixtures

    USGS Publications Warehouse

    Balistrieri, Laurie S.; Mebane, Christopher A.

    2013-01-01

    The toxicity of single and multiple metal (Cd, Cu, Pb, and Zn) solutions to trout is predicted using an approach that combines calculations of: (1) solution speciation; (2) competition and accumulation of cations (H, Ca, Mg, Na, Cd, Cu, Pb, and Zn) on low abundance, high affinity and high abundance, low affinity biotic ligand sites; (3) a toxicity function that accounts for accumulation and potency of individual toxicants; and (4) biological response. The approach is evaluated by examining water composition from single metal toxicity tests of trout at 50% mortality, results of theoretical calculations of metal accumulation on fish gills and associated mortality for single, binary, ternary, and quaternary metal solutions, and predictions for a field site impacted by acid rock drainage. These evaluations indicate that toxicity of metal mixtures depends on the relative affinity and potency of toxicants for a given aquatic organism, suites of metals in the mixture, dissolved metal concentrations and ratios, and background solution composition (temperature, pH, and concentrations of major ions and dissolved organic carbon). A composite function that incorporates solution composition, affinity and competition of cations for two types of biotic ligand sites, and potencies of hydrogen and individual metals is proposed as a tool to evaluate potential toxicity of environmental solutions to trout.

  14. Toxicity test of xanthone from mangosteen on zebrafish embryos

    NASA Astrophysics Data System (ADS)

    Noordin, Muhammad Akram Mohd; Noor, Mahanem Mat; Kamaruddin, Wan Mohd Aizat Wan; Lazim, Azwan Mat; Fazry, Shazrul

    2016-11-01

    Xanthone is a chemical compound identified in mangosteen pericarp. A previous study showed that xanthone has anti-proliferating effect on cancer cells. In this study we investigate the toxicity level of xanthone in zebrafish embryo to for future reference on other animal model. We employed Fish Embryo Toxicity (FET) assay to determine the toxicity level of different concentrations of xanthone. Embryos were observed at 24, 48 and 72 hours post fertilization (hpf) under microscope at 4× magnification. The extract showed toxicity effect on embryo at concentrations of 250, 125 and 62.5 µg/mL. Concentrations at 15.63, 7.81 and 3.91 µg / mL of xanthone did not harm the embryos and showed 100% of survival.

  15. The Impact of a Nickel-Copper Smelter on Concentrations of Toxic Elements in Local Wild Food from the Norwegian, Finnish, and Russian Border Regions

    PubMed Central

    Hansen, Martine D.; Nøst, Therese H.; Heimstad, Eldbjørg S.; Evenset, Anita; Dudarev, Alexey A.; Rautio, Arja; Myllynen, Päivi; Dushkina, Eugenia V.; Jagodic, Marta; Christensen, Guttorm N.; Anda, Erik E.; Brustad, Magritt; Sandanger, Torkjel M.

    2017-01-01

    Toxic elements emitted from the Pechenganickel complex on the Kola Peninsula have caused concern about potential effects on local wild food in the border regions between Norway, Finland and Russia. The aim of this study was to assess Ni, Cu, Co, As, Pb, Cd, and Hg concentrations in local wild foods from these border regions. During 2013–2014, we collected samples of different berry, mushroom, fish, and game species from sites at varying distances from the Ni-Cu smelter in all three border regions. Our results indicate that the Ni-Cu smelter is the main source of Ni, Co, and As in local wild foods, whereas the sources of Pb and Cd are more complex. We observed no consistent trends for Cu, one of the main toxic elements emitted by the Ni-Cu smelter; nor did we find any trend for Hg in wild food. Concentrations of all investigated toxic elements were highest in mushrooms, except for Hg, which was highest in fish. EU maximum levels of Pb, Cd, and Hg were exceeded in some samples, but most had levels considered safe for human consumption. No international thresholds exist for the other elements under study. PMID:28657608

  16. The Impact of a Nickel-Copper Smelter on Concentrations of Toxic Elements in Local Wild Food from the Norwegian, Finnish, and Russian Border Regions.

    PubMed

    Hansen, Martine D; Nøst, Therese H; Heimstad, Eldbjørg S; Evenset, Anita; Dudarev, Alexey A; Rautio, Arja; Myllynen, Päivi; Dushkina, Eugenia V; Jagodic, Marta; Christensen, Guttorm N; Anda, Erik E; Brustad, Magritt; Sandanger, Torkjel M

    2017-06-28

    Toxic elements emitted from the Pechenganickel complex on the Kola Peninsula have caused concern about potential effects on local wild food in the border regions between Norway, Finland and Russia. The aim of this study was to assess Ni, Cu, Co, As, Pb, Cd, and Hg concentrations in local wild foods from these border regions. During 2013-2014, we collected samples of different berry, mushroom, fish, and game species from sites at varying distances from the Ni-Cu smelter in all three border regions. Our results indicate that the Ni-Cu smelter is the main source of Ni, Co, and As in local wild foods, whereas the sources of Pb and Cd are more complex. We observed no consistent trends for Cu, one of the main toxic elements emitted by the Ni-Cu smelter; nor did we find any trend for Hg in wild food. Concentrations of all investigated toxic elements were highest in mushrooms, except for Hg, which was highest in fish. EU maximum levels of Pb, Cd, and Hg were exceeded in some samples, but most had levels considered safe for human consumption. No international thresholds exist for the other elements under study.

  17. Pesticide toxicity index for freshwater aquatic organisms

    USGS Publications Warehouse

    Munn, Mark D.; Gilliom, Robert J.

    2001-01-01

    The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is designed to assess current water-quality conditions, changes in water quality over time, and the effects of natural and human factors on water quality for the Nation's streams and ground-water resources. For streams, one of the most difficult parts of the assessment is to link chemical conditions to effects on aquatic biota, particularly for pesticides, which tend to occur in streams as complex mixtures with strong seasonal patterns. A Pesticide Toxicity Index (PTI) was developed that combines pesticide exposure of aquatic biota (measured concentrations of pesticides in stream water) with toxicity estimates (standard endpoints from laboratory bioassays) to produce a single index value for a sample or site. The development of the PTI was limited to pesticide compounds routinely measured in NAWQA studies and to toxicity data readily available from existing databases. Qualifying toxicity data were found for one or more types of test organisms for 75 of the 83 pesticide compounds measured in NAWQA samples, but with a wide range of bioassays per compound (1 to 65). There were a total of 2,824 bioassays for the 75 compounds, including 287 48-hour EC50 values (concentration at which 50 percent of test organisms exhibit a nonlethal response) for freshwater cladocerans, 585 96-hour LC50 values (concentration lethal to 50 percent of test organisms) for freshwater benthic invertebrates, and 1,952 96-hour LC50 values for freshwater fish. The PTI for a particular sample is the sum of toxicity quotients (measured concentration divided by the median toxicity concentration from bioassays) for each detected pesticide. The PTI can be calculated for specific groups of pesticides and for specific taxonomic groups.While the PTI does not determine whether water in a sample is toxic, its values can be used to rank or compare the toxicity of samples or sites on a relative basis for use in further analysis or

  18. Purified terephthalic acid wastewater biodegradation and toxicity.

    PubMed

    Zhang, Xu-xiang; Wan, Yu-qiu; Cheng, Shu-pei; Sun, Shi-lei; Zhu, Cheng-jun; Li, Wei-xin; Zhang, Xiao-chun; Wang, Gui-lin; Lu, Jian-hua; Luo, Xiang; Gu, Ji-dong

    2005-01-01

    The biodegradation and toxicity of the purified terephthalic acid (PTA) processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process (CASP). Sludge loading rate (SLR) for Fhhh to COD of the wastewater was 1.09 d(-1) and to PTA in the wastewater was 0.29 d(-1). The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 (median lethal concentration) to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were 5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

  19. Pharmacokinetic drivers of toxicity for basic molecules: Strategy to lower pKa results in decreased tissue exposure and toxicity for a small molecule Met inhibitor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Diaz, Dolores, E-mail: diaz.dolores@gene.com; Ford, Kevin A.; Hartley, Dylan P.

    Several toxicities are clearly driven by free drug concentrations in plasma, such as toxicities related to on-target exaggerated pharmacology or off-target pharmacological activity associated with receptors, enzymes or ion channels. However, there are examples in which organ toxicities appear to correlate better with total drug concentrations in the target tissues, rather than with free drug concentrations in plasma. Here we present a case study in which a small molecule Met inhibitor, GEN-203, with significant liver and bone marrow toxicity in preclinical species was modified with the intention of increasing the safety margin. GEN-203 is a lipophilic weak base as demonstratedmore » by its physicochemical and structural properties: high LogD (distribution coefficient) (4.3) and high measured pKa (7.45) due to the basic amine (N-ethyl-3-fluoro-4-aminopiperidine). The physicochemical properties of GEN-203 were hypothesized to drive the high distribution of this compound to tissues as evidenced by a moderately-high volume of distribution (Vd > 3 l/kg) in mouse and subsequent toxicities of the compound. Specifically, the basicity of GEN-203 was decreased through addition of a second fluorine in the 3-position of the aminopiperidine to yield GEN-890 (N-ethyl-3,3-difluoro-4-aminopiperidine), which decreased the volume of distribution of the compound in mouse (Vd = 1.0 l/kg), decreased its tissue drug concentrations and led to decreased toxicity in mice. This strategy suggests that when toxicity is driven by tissue drug concentrations, optimization of the physicochemical parameters that drive tissue distribution can result in decreased drug concentrations in tissues, resulting in lower toxicity and improved safety margins. -- Highlights: ► Lower pKa for a small molecule: reduced tissue drug levels and toxicity. ► New analysis tools to assess electrostatic effects and ionization are presented. ► Chemical and PK drivers of toxicity can be leveraged to improve safety.« less

  20. [Concentrations of alkaloids, cyanogenic glycosides, polyphenols and saponins in selected medicinal plants from Ecuador and their relationship with acute toxicity against Artemia salina].

    PubMed

    Jaramillo Jaramillo, Carmita; Jaramillo Espinoza, Anyi; D'Armas, Haydelba; Troccoli, Luis; Rojas de Astudillo, Luisa

    2016-09-01

    Alkaloids, polyphenols, cyanogenic glycosides and saponins are among the main chemical compounds synthesized by plants but not considered essential for their basic metabolism. These compounds have different functions in plants, and have been recognized with medicinal and pharmacological properties. In this research, concentrations of the mentioned secondary metabolites were determined in the medicinal plants Artemisia absinthium, Cnidoscolus aconitifolius, Parthenium hysterophorus, Piper carpunya and Taraxacum officinale, from Ecuador, and related with cytotoxic effects against Artemia salina. Alcoholic and aqueous extracts from leaves of these selected plants were prepared at different concentrations. To assess cytotoxicity of these extracts, different bioassays with A. salina were undertaken, and the mortality rates and LC50 were obtained. Besides, concentrations of alkaloids, cyanogenic glycosides, phenols, tannins and saponins were determined by spectrophotometric methods; this constituted the first report of quantification of secondary metabolites in the selected plants from Ecuador. T. officinale had the highest concentration of total phenols (22.30 ± 0.23 mg/g) and tannins (11.70 ± 0.10 mg/g), C. aconitifolius of cyanogenic glycosides (5.02 ± 0.37 µg/g) and P. hysterophorus of saponins (6.12 ± 0.02 mg/g). Tannins values obtained were not adverse to their consumption. Alcoholic and aqueous extracts of selected plants had hemolytic activity depending on the concentration of saponins. Although the values of cyanogenic glycosides were permissible, it was necessary to monitor the presence of this metabolite in plants to minimize health problems. LC50 values ranged from extremely toxic (3.37 µg/mL) to highly toxic (274.34 μg/mL), in P. carpunya and T. officinale, respectively. From correlation analysis, it was observed that increase values of alkaloids concentrations had highly significant (p<0.001) acute toxicity against A. salina, while at a higher

  1. Cardiovascular toxicity with levetiracetam overdose.

    PubMed

    Page, Colin B; Mostafa, Ahmed; Saiao, Ana; Grice, Jeffrey E; Roberts, Michael S; Isbister, Geoffrey K

    2016-01-01

    To describe the cardiovascular toxicity and pharmacokinetics of levetiracetam in overdose. A 43-year-old female presented 8 h post ingestion of 60-80 g of levetiracetam with mild central nervous system depression, bradycardia, hypotension and oliguria. Her cardiovascular toxicity transiently responded to atropine and intravenous fluids. A bedside echocardiogram demonstrated normal left and right ventricular contractility. Despite her cardiovascular toxicity and oliguria, she had normal serial venous lactates and renal function; and made a complete recovery over 48 h. Her levetiracetam concentration was 463 mcg/ml 8 h post ingestion (therapeutic range 10-40 mcg/ml) and her concentration-time data best fitted a one-compartment model with first-order input and an elimination half-life of 10.4 h. Levetiracetam in large ingestions appears to cause bradycardia and hypotension that is potentially responsive to atropine and intravenous fluids. Based on a normal echocardiogram, the mechanism for this effect may be levetiracetam acting at muscarinic receptors at high concentration. The pharmacokinetics of levetiracetam in overdose appeared to be similar to therapeutic levetiracetam dosing.

  2. Chronic toxicity of an environmentally relevant mixture of pharmaceuticals to three aquatic organisms (alga, daphnid, and fish).

    PubMed

    Watanabe, Haruna; Tamura, Ikumi; Abe, Ryoko; Takanobu, Hitomi; Nakamura, Ataru; Suzuki, Toshinari; Hirose, Akihiko; Nishimura, Tetsuji; Tatarazako, Norihisa

    2016-04-01

    Principles of concentration addition and independent action have been used as effective tools to predict mixture toxicity based on individual component toxicity. The authors investigated the toxicity of a pharmaceutical mixture composed of the top 10 detected active pharmaceutical ingredients (APIs) in the Tama River (Tokyo, Japan) in a relevant concentration ratio. Both individual and mixture toxicities of the 10 APIs were evaluated by 3 short-term chronic toxicity tests using the alga Pseudokirchneriella subcapitata, the daphnid Ceriodaphnia dubia, and the zebrafish Danio rerio. With the exception of clarithromycin toxicity to alga, the no-observed-effect concentration of individual APIs for each test species was dramatically higher than the highest concentration of APIs found in the environment. The mixture of 10 APIs resulted in toxicity to alga, daphnid, and fish at 6.25 times, 100 times, and 15,000 times higher concentrations, respectively, than the environmental concentrations of individual APIs. Predictions by concentration addition and independent action were nearly identical for alga, as clarithromycin was the predominant toxicant in the mixture. Both predictions described the observed mixture toxicity to alga fairly well, whereas they slightly underestimated the observed mixture toxicity in the daphnid test. In the fish embryo test, the observed toxicity fell between the predicted toxicity by concentration addition and independent action. These results suggested that the toxicity of environmentally relevant pharmaceutical mixtures could be predicted by individual toxicity using either concentration addition or independent action. © 2015 SETAC.

  3. Comparative toxicity of silver nanoparticles and silver ions to Escherichia coli.

    PubMed

    Choi, Yoojin; Kim, Hyun-A; Kim, Kyoung-Woong; Lee, Byung-Tae

    2018-04-01

    With the increase in silver (Ag)-based products in our lives, it is essential to test the potential toxicity of silver nanoparticles (AgNPs) and silver ions (Ag ions) on living organisms under various conditions. Here, we investigated the toxicity of AgNPs with Ag ions to Escherichia coli K-12 strain under various conditions. We observed that both AgNPs and Ag ions display antibacterial activities, and that Ag ions had higher toxicity to E. coli K-12 strain than AgNPs under the same concentrations. To understand the toxicity of AgNPs at a cellular level, reactive oxygen species (ROS) enzymes were detected for use as antioxidant enzymatic biomarkers. We have also studied the toxicity of AgNPs and Ag ions under various coexistence conditions including: fixed total concentration, with a varied the ratio of AgNPs to Ag ions; fixed the AgNPs concentration and then increased the Ag ions concentration; fixed Ag ions concentration and then increasing the AgNPs concentration. Exposure to AgNPs and Ag ions clearly had synergistic toxicity; however, decreased toxicity (for a fixed AgNPs concentration of 5mg/L, after increasing the Ag ions concentration) to E. coli K-12 strain. AgNPs and Ag ions in the presence of L-cysteine accelerated the bacterial cell growth rate, thereby reducing the bioavailability of Ag ions released from AgNPs under the single and coexistence conditions. Further works are needed to consider this potential for AgNPs and Ag ions toxicity across a range of environmental conditions. As silver nanoparticles (AgNPs)-based products are being broadly used in commercial industries, an ecotoxicological understanding of the AgNPs being released into the environment should be further considered. Here, we investigate the comparative toxicity of AgNPs and silver ions (Ag ions) to Escherichia coli K-12 strain, a representative ecotoxicological bioreporter. This study showed that toxicities of AgNPs and Ag ions to E. coli K-12 strain display different relationships

  4. 46 CFR 153.526 - Toxic vapor detectors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Toxic vapor detectors. 153.526 Section 153.526 Shipping... Requirements § 153.526 Toxic vapor detectors. (a) When Table 1 refers to this section, a tankship must have two toxic vapor detectors, at least one of which must be portable, each able to measure vapor concentrations...

  5. 46 CFR 153.526 - Toxic vapor detectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Toxic vapor detectors. 153.526 Section 153.526 Shipping... Requirements § 153.526 Toxic vapor detectors. (a) When Table 1 refers to this section, a tankship must have two toxic vapor detectors, at least one of which must be portable, each able to measure vapor concentrations...

  6. 46 CFR 153.526 - Toxic vapor detectors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Toxic vapor detectors. 153.526 Section 153.526 Shipping... Requirements § 153.526 Toxic vapor detectors. (a) When Table 1 refers to this section, a tankship must have two toxic vapor detectors, at least one of which must be portable, each able to measure vapor concentrations...

  7. 46 CFR 153.526 - Toxic vapor detectors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Toxic vapor detectors. 153.526 Section 153.526 Shipping... Requirements § 153.526 Toxic vapor detectors. (a) When Table 1 refers to this section, a tankship must have two toxic vapor detectors, at least one of which must be portable, each able to measure vapor concentrations...

  8. 46 CFR 153.526 - Toxic vapor detectors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Toxic vapor detectors. 153.526 Section 153.526 Shipping... Requirements § 153.526 Toxic vapor detectors. (a) When Table 1 refers to this section, a tankship must have two toxic vapor detectors, at least one of which must be portable, each able to measure vapor concentrations...

  9. Factors influencing alert acceptance: a novel approach for predicting the success of clinical decision support

    PubMed Central

    Seidling, Hanna M; Phansalkar, Shobha; Seger, Diane L; Paterno, Marilyn D; Shaykevich, Shimon; Haefeli, Walter E

    2011-01-01

    Background Clinical decision support systems can prevent knowledge-based prescription errors and improve patient outcomes. The clinical effectiveness of these systems, however, is substantially limited by poor user acceptance of presented warnings. To enhance alert acceptance it may be useful to quantify the impact of potential modulators of acceptance. Methods We built a logistic regression model to predict alert acceptance of drug–drug interaction (DDI) alerts in three different settings. Ten variables from the clinical and human factors literature were evaluated as potential modulators of provider alert acceptance. ORs were calculated for the impact of knowledge quality, alert display, textual information, prioritization, setting, patient age, dose-dependent toxicity, alert frequency, alert level, and required acknowledgment on acceptance of the DDI alert. Results 50 788 DDI alerts were analyzed. Providers accepted only 1.4% of non-interruptive alerts. For interruptive alerts, user acceptance positively correlated with frequency of the alert (OR 1.30, 95% CI 1.23 to 1.38), quality of display (4.75, 3.87 to 5.84), and alert level (1.74, 1.63 to 1.86). Alert acceptance was higher in inpatients (2.63, 2.32 to 2.97) and for drugs with dose-dependent toxicity (1.13, 1.07 to 1.21). The textual information influenced the mode of reaction and providers were more likely to modify the prescription if the message contained detailed advice on how to manage the DDI. Conclusion We evaluated potential modulators of alert acceptance by assessing content and human factors issues, and quantified the impact of a number of specific factors which influence alert acceptance. This information may help improve clinical decision support systems design. PMID:21571746

  10. Warming reduces tall fescue abundance but stimulates toxic alkaloid concentrations in transition zone pastures of the U.S.

    NASA Astrophysics Data System (ADS)

    Mcculley, Rebecca; Bush, Lowell; Carlisle, Anna; Ji, Huihua; Nelson, Jim

    2014-10-01

    Tall fescue pastures cover extensive acreage in the eastern half of the United States and contribute to important ecosystem services, including the provisioning of forage for grazing livestock. Yet little is known concerning how these pastures will respond to climate change. Tall fescue’s ability to persist and provide forage under a warmer and wetter environment, as is predicted for much of this region as a result of climate change, will likely depend on a symbiotic relationship the plant can form with the fungal endophyte, Epichloë coenophiala. While this symbiosis can confer environmental stress tolerance to the plant, the endophyte also produces alkaloids toxic to insects (e.g., lolines) and mammals (ergots; which can cause ‘fescue toxicosis’ in grazing animals). The negative animal health and economic consequences of fescue toxicosis make understanding the response of the tall fescue symbiosis to climate change critical for the region. We experimentally increased temperature (+3oC) and growing season precipitation (+30% of the long-term mean) from 2009 - 2013 in a mixed species pasture, that included a tall fescue population that was 40% endophyte-infected. Warming reduced the relative abundance of tall fescue within the plant community, and additional precipitation did not ameliorate this effect. Warming did not alter the incidence of endophyte infection within the tall fescue population; however, warming significantly increased concentrations of ergot alkaloids (by 30-40%) in fall-harvested endophyte-infected individuals. Warming alone did not affect loline alkaloid concentrations, but when combined with additional precipitation, levels increased in fall-harvested material. Although future warming may reduce the dominance of tall fescue in eastern U.S. pastures and have limited effect on the incidence of endophyte infection, persisting endophyte-infected tall fescue will have higher concentrations of toxic alkaloids which may exacerbate fescue

  11. Warming reduces tall fescue abundance but stimulates toxic alkaloid concentrations in transition zone pastures of the U.S.

    PubMed Central

    McCulley, Rebecca L.; Bush, Lowell P.; Carlisle, Anna E.; Ji, Huihua; Nelson, Jim A.

    2014-01-01

    Tall fescue pastures cover extensive acreage in the eastern half of the United States and contribute to important ecosystem services, including the provisioning of forage for grazing livestock. Yet little is known concerning how these pastures will respond to climate change. Tall fescue's ability to persist and provide forage under a warmer and wetter environment, as is predicted for much of this region as a result of climate change, will likely depend on a symbiotic relationship the plant can form with the fungal endophyte, Epichloë coenophiala. While this symbiosis can confer environmental stress tolerance to the plant, the endophyte also produces alkaloids toxic to insects (e.g., lolines) and mammals (ergots; which can cause “fescue toxicosis” in grazing animals). The negative animal health and economic consequences of fescue toxicosis make understanding the response of the tall fescue symbiosis to climate change critical for the region. We experimentally increased temperature (+3°C) and growing season precipitation (+30% of the long-term mean) from 2009–2013 in a mixed species pasture, that included a tall fescue population that was 40% endophyte-infected. Warming reduced the relative abundance of tall fescue within the plant community, and additional precipitation did not ameliorate this effect. Warming did not alter the incidence of endophyte infection within the tall fescue population; however, warming significantly increased concentrations of ergot alkaloids (by 30–40%) in fall-harvested endophyte-infected individuals. Warming alone did not affect loline alkaloid concentrations, but when combined with additional precipitation, levels increased in fall-harvested material. Although future warming may reduce the dominance of tall fescue in eastern U.S. pastures and have limited effect on the incidence of endophyte infection, persisting endophyte-infected tall fescue will have higher concentrations of toxic alkaloids which may exacerbate fescue

  12. Leachate composition and toxicity assessment: an integrated approach correlating physicochemical parameters and toxicity of leachates from MSW landfill in Delhi.

    PubMed

    Gupta, Anshu; Paulraj, R

    2017-07-01

    Landfills are considered the most widely practiced method for disposal of municipal solid waste (MSW) and 95% of the total MSW collected worldwide is disposed of in landfills. Leachate produced from MSW landfills may contain a number of pollutants and pose a potential environmental risk for surface as well as ground water. In the present study, chemical analysis and toxicity assessment of landfill leachate have been carried out. Leachate samples were collected from Ghazipur landfill site, New Delhi. Leachates were characterized by measuring the concentration of heavy metals (Pb, Cu, Cr and Ni), 5-day biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD), pH, electrical conductivity and SO 4 2 -. For toxicity testing of leachate, Triticum aestivum (wheat) was selected and testing was done in a time- and dose-dependent manner using the crude leachate. Median lethal concentration after 24 and 48 h of exposure was observed. The main objective of this study was to evaluate toxicity of MSW landfill leachate and establish a possible correlation between the measured physicochemical parameters and resultant toxicity. Statistical analysis showed that toxicity was dependent on the concentration of heavy metals (Pb, Cu), conductivity, and organic matter (COD and BOD5).

  13. An evaluation of the seven-day toxicity test with Americamysis bahia (formerly Mysidopsis bahia)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lussier, S.M.; Kuhn, A.; Comeleo, R.

    The 7-d test measuring survival, growth, and fecundity of Americamysis bahia (formerly Mysidopsis bahia) was developed for estimating the chronic toxicity of effluents and associated receiving waters for National Pollutant Discharge Elimination System permits. Currently, this test and its derivatives are also used in toxicity identification evaluation (TIE), risk assessment, and other applications. To evaluate the relative sensitivity of three measurement endpoints (survival, growth, and fecundity), the authors analyzed results from 115 tests with effluents, organic or inorganic chemicals, and receiving waters suspected of being toxic. Controls for 78 of these achieved acceptable survival and growth. Fifty of these 78more » tests also achieved acceptable control fecundity. In the 47 tests with significant effects, survival was the most sensitive response in 57%, fecundity in 30%, and growth in 30%. There was little duplication in responses. Improving pretest holding conditions by decreasing the maximum density from {approximately}20 to 10 animals/L and increasing the temperature from {approximately}26 C to a range of 26 to 27 C improved the growth and fecundity in controls. Although the percentage of tests achieving acceptable control survival and growth decreased from 93 to 86%, the percentage achieving acceptable fecundity in controls increased from 60 to 97%. Seasonal differences in fecundity were detected among control groups. Although variable, fecundity is often the most sensitive measure of response. The 7-d mysid test estimates the chronic toxicity of effluents most effectively when all three endpoints are used.« less

  14. Evaluation of the toxicity of sediments from the Anniston PCB Site to the mussel Lampsilis siliquoidea

    USGS Publications Warehouse

    Schein, Allison; Sinclair, Jesse A.; MacDonald, Donald D.; Ingersoll, Christopher G.; Kemble, Nile E.; Kunz, James L.

    2015-01-01

    concentrations of PCBs were associated with the highest concentrations of PAHs, PCDDs/PCDFs, and organochlorine pesticides. Specifically, sediments 08, 18, and 19 exceeded probable effect concentration quotients (PEC-Qs) of 1.0 for all organic classes of contaminants. These three sediment samples also had high concentrations of mercury and lead, which were the only metals found at elevated concentrations (i.e., above the probable effect concentration [PEC]) in the samples collected. Many sediment samples were highly contaminated with mercury, based on comparisons to samples collected from reference locations. The whole-sediment laboratory toxicity tests conducted with L. siliquoidea met the test acceptability criteria (e.g., control survival was greater than or equal to 80%). Survival of mussels was high in most samples, with 4 of 23 samples (17%) classified as toxic based on the survival endpoint. Biomass and weight were more sensitive endpoints for the L. siliquoidea toxicity tests, with both endpoints classifying 52% of the samples as toxic. Samples 19 and 30 were most toxic to L. siliquoidea, as they were classified as toxic according to all four endpoints (survival, biomass, weight, and length). Mussels were less sensitive in toxicity tests conducted with sediments from the Anniston PCB Site than Hyalella azteca and Chironomus dilutus. Biomass of L. siliquoidea was less sensitive compared to biomass of H. azteca or biomass of larval C. dilutus. Based on the most sensitive endpoint for each species, 52% of the samples were toxic to L. siliquoidea, whereas 67% of sediments were toxic to H. azteca (based on reproduction) and 65% were toxic to C. dilutus (based on adult biomass). The low-risk toxicity threshold (TTLR) was higher for L. siliquoidea biomass (e.g., 20,400 µg/kg dry weight [DW]) compared to that for H. azteca reproduction (e.g., 499 µg/kg DW) or C. dilutus adult biomass (e.g., 1,140 µg/kg DW; MacDonald et al. 2014). While mussels such as L. sili

  15. Cryoprotectant Toxicity: Facts, Issues, and Questions

    PubMed Central

    2015-01-01

    Abstract High levels of penetrating cryoprotectants (CPAs) can eliminate ice formation during cryopreservation of cells, tissues, and organs to cryogenic temperatures. But CPAs become increasingly toxic as concentration increases. Many strategies have been attempted to overcome the problem of eliminating ice while minimizing toxicity, such as attempting to optimize cooling and warming rates, or attempting to optimize time of adding individual CPAs during cooling. Because strategies currently used are not adequate, CPA toxicity remains the greatest obstacle to cryopreservation. CPA toxicity stands in the way of cryogenic cryopreservation of human organs, a procedure that has the potential to save many lives. This review attempts to describe what is known about CPA toxicity, theories of CPA toxicity, and strategies to reduce CPA toxicity. Critical analysis and suggestions are also included. PMID:25826677

  16. OECD validation study to assess intra- and inter-laboratory reproducibility of the zebrafish embryo toxicity test for acute aquatic toxicity testing.

    PubMed

    Busquet, François; Strecker, Ruben; Rawlings, Jane M; Belanger, Scott E; Braunbeck, Thomas; Carr, Gregory J; Cenijn, Peter; Fochtman, Przemyslaw; Gourmelon, Anne; Hübler, Nicole; Kleensang, André; Knöbel, Melanie; Kussatz, Carola; Legler, Juliette; Lillicrap, Adam; Martínez-Jerónimo, Fernando; Polleichtner, Christian; Rzodeczko, Helena; Salinas, Edward; Schneider, Katharina E; Scholz, Stefan; van den Brandhof, Evert-Jan; van der Ven, Leo T M; Walter-Rohde, Susanne; Weigt, Stefan; Witters, Hilda; Halder, Marlies

    2014-08-01

    The OECD validation study of the zebrafish embryo acute toxicity test (ZFET) for acute aquatic toxicity testing evaluated the ZFET reproducibility by testing 20 chemicals at 5 different concentrations in 3 independent runs in at least 3 laboratories. Stock solutions and test concentrations were analytically confirmed for 11 chemicals. Newly fertilised zebrafish eggs (20/concentration and control) were exposed for 96h to chemicals. Four apical endpoints were recorded daily as indicators of acute lethality: coagulation of the embryo, lack of somite formation, non-detachment of the tail bud from the yolk sac and lack of heartbeat. Results (LC50 values for 48/96h exposure) show that the ZFET is a robust method with a good intra- and inter-laboratory reproducibility (CV<30%) for most chemicals and laboratories. The reproducibility was lower (CV>30%) for some very toxic or volatile chemicals, and chemicals tested close to their limit of solubility. The ZFET is now available as OECD Test Guideline 236. Considering the high predictive capacity of the ZFET demonstrated by Belanger et al. (2013) in their retrospective analysis of acute fish toxicity and fish embryo acute toxicity data, the ZFET is ready to be considered for acute fish toxicity for regulatory purposes. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Toxicity of trifluoroacetate to aquatic organisms

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Berends, A.G.; Rooij, C.G. de; Boutonnet, J.C.

    1999-05-01

    As a result of the atmospheric degradation of several hydrofluorocarbons and hydrochlorofluorocarbons, trifluoroacetate (TFA) will be formed. Through precipitation, TFA will enter aquatic ecosystems. To evaluate the impact on the aquatic environment, an aquatic toxicity testing program was carried out with sodium trifluoroacetate (NaTFA). During acute toxicity tests, no effects of NaTFA on water fleas (Daphnia magna) and zebra fish (Danio retrio) were found at a concentration of 1,200 mg/L. A 7-d study with duckweed (Lemna gibba Ge) revealed a NOEC of 300 mg/L. On the basis of the results of five toxicity tests with Selenastrum capricornutum, they determined amore » NOEC of 0.12 mg/L. However, algal toxicity tests with NaTFA and Chlorella vulgaris, Scenedesmus subspicatus, Chlamydomonas reinhardtii, Dunaliella tertiolecta, Eugelan gracilis, Phaeodactylum tricornutum, Navicula pelliculosa, Skeletonema costatum, Anabaena flos-aquae, and Microcystis aeruginosa resulted in EC50 values that were all higher than 100 mg/L. The toxicity of TFA to S. capricornutum could be due to metabolic defluorination to monofluoroacetate (MFA), which is known to inhibit the citric acid cycle. A toxicity test with MFA and S. capricornutum revealed it to be about three orders of magnitude more toxic than TFA. However, a bioactivation study revealed that defluorination of TFA was less than 4%. On the other hand, S. capricornutum exposed to a toxic concentration of NaTFA showed a recovery of growth when citric acid was added, suggesting that TFA (or a metabolite of TFA) interferes with the citric acid cycle. A recovery of the growth of S. capricornutum was also found when TFA was removed from the test solutions. Therefore, TFA should be considered algistatic and not algicidic for S. capricornutum. On the basis of the combined results of the laboratory tests and a previously reported semi-field study, they can consider a TFA concentration of 0.10 mg/L as safe for the aquatic ecosystem.« less

  18. Aspects of nitrogen dioxide toxicity in environmental urban concentrations in human nasal epithelium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Koehler, C.; Ginzkey, C.; Friehs, G.

    Cytotoxicity and genotoxicity of nitrogen dioxide (NO{sub 2}) as part of urban exhaust pollution are widely discussed as potential hazards to human health. This study focuses on toxic effects of NO{sub 2} in realistic environmental concentrations with respect to the current limit values in a human target tissue of volatile xenobiotics, the epithelium of the upper aerodigestive tract. Nasal epithelial cells of 10 patients were cultured as an air-liquid interface and exposed to 0.01 ppm NO{sub 2}, 0.1 ppm NO{sub 2}, 1 ppm NO{sub 2}, 10 ppm NO{sub 2} and synthetic air for half an hour. After exposure, genotoxicity wasmore » evaluated by the alkaline single-cell microgel electophoresis (Comet) assay and by induction of micronuclei in the micronucleus test. Depression of proliferation and cytotoxic effects were determined using the micronucleus assay and trypan blue exclusion assay, respectively. The experiments revealed genotoxic effects by DNA fragmentation starting at 0.01 ppm NO{sub 2} in the Comet assay, but no micronucleus inductions, no changes in proliferation, no signs of necrosis or apoptosis in the micronucleus assay, nor did the trypan blue exclusion assay show any changes in viability. The present data reveal a possible genotoxicity of NO{sub 2} in urban concentrations in a screening test. However, permanent DNA damage as indicated by the induction of micronuclei was not observed. Further research should elucidate the effects of prolonged exposure.« less

  19. Acute toxicity of ingested fluoride.

    PubMed

    Whitford, Gary Milton

    2011-01-01

    This chapter discusses the characteristics and treatment of acute fluoride toxicity as well as the most common sources of overexposure, the doses that cause acute toxicity, and factors that can influence the clinical outcome. Cases of serious systemic toxicity and fatalities due to acute exposures are now rare, but overexposures causing toxic signs and symptoms are not. The clinical course of systemic toxicity from ingested fluoride begins with gastric signs and symptoms, and can develop with alarming rapidity. Treatment involves minimizing absorption by administering a solution containing calcium, monitoring and managing plasma calcium and potassium concentrations, acid-base status, and supporting vital functions. Approximately 30,000 calls to US poison control centers concerning acute exposures in children are made each year, most of which involve temporary gastrointestinal effects, but others require medical treatment. The most common sources of acute overexposures today are dental products - particularly dentifrices because of their relatively high fluoride concentrations, pleasant flavors, and their presence in non-secure locations in most homes. For example, ingestion of only 1.8 ounces of a standard fluoridated dentifrice (900-1,100 mg/kg) by a 10-kg child delivers enough fluoride to reach the 'probably toxic dose' (5 mg/kg body weight). Factors that may influence the clinical course of an overexposure include the chemical compound (e.g. NaF, MFP, etc.), the age and acid-base status of the individual, and the elapsed time between exposure and the initiation of treatment. While fluoride has well-established beneficial dental effects and cases of serious toxicity are now rare, the potential for toxicity requires that fluoride-containing materials be handled and stored with the respect they deserve. Copyright © 2011 S. Karger AG, Basel.

  20. Influence of the method of fluoride administration on toxicity and fluoride concentrations in Japanese quail

    USGS Publications Warehouse

    Fleming, W.J.; Schuler, C.A.

    1988-01-01

    Young Japanese quail (Coturnix japonica) were administered NaF for 16 d either in their diet or by esophageal intubation. Based on the total fluoride ion (Emg F-) intake over the l6-d experimental period, fluoride administered by intubation was at least six times more toxic than that fed in the diet. Dietary concentrations of 1,000 ppm F- (Emg F- for 16 d = approx. 144) produced no mortality, whereas intubated doses produced 73% or greater mortality in all groups administered 54 mg F- /kg/d or more (Emg F- for 16 d _ approx. 23 mg). GraphIc companson of the regression of log F- ppm in femurs/mg F- intake showed that fluoride levels in the femurs of quail administered fluoride by intubation were higher than in those administered fluoride in the diet.

  1. Toxicity of sediments and pore water from Brunswick Estuary, Georgia

    USGS Publications Warehouse

    Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

    1993-01-01

    A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

  2. Evaluation of toxic and interactive toxic effects of three agrochemicals and copper using a battery of microbiotests.

    PubMed

    Kungolos, A; Emmanouil, C; Tsiridis, V; Tsiropoulos, N

    2009-08-01

    Three commonly used test organisms of different trophic levels (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) were exposed to selected agrochemicals (fosthiazate, metalaxyl-M, imidacloprid) and copper, in single doses or in binary mixtures. The toxicity of each single compound varied up to two orders of magnitude, depending on the test species examined. V. fischeri was the most sensitive test organism regarding fosthiazate and metalaxyl-M, indicating an IC(50) value of 0.20 mg/L (0.17-0.25 mg/L) and 0.88 mg/L (0.35-1.57 mg/L), respectively. Imidacloprid was the least toxic compound, indicating an EC(50) value on D. magna of 64.6 mg/L (43.3-122.5 mg/L) and an IC(50) value on V. fischeri of 226 mg/L (159-322 mg/L), while for imidacloprid at a concentration of 1000 mg/L the effect on P. subcapitata was lower than 50%. Copper was the most toxic compound towards all test organisms exhibiting the highest toxic effect on P. subcapitata, with an IC(50) value of 0.05 mg/L (0.003-0.008 mg/L). The toxic effects of the binary mixtures have been compared to the theoretically expected effect, resulting from a simple mathematical model based on the theory of probabilities. The independent action model was used in order to predict the theoretically expected effect. The interactive effects were mostly antagonistic or additive, while in few cases (interactive effects of metalaxyl-M and copper on V. fischeri) a synergistic mode of action was observed for some concentration combinations. Experiments showed that interactive effects of chemicals may vary depending on the test species used as well as on the chemicals and their respective concentrations. Although most of the concentrations of chemicals tested in this study are higher than the ones usually found in natural environment, the evaluation of their interactive toxic effects using a battery of bioassays may comprise a useful tool for the estimation of the environmental hazard of chemicals.

  3. Toxicity evaluation and prediction of toxic chemicals on activated sludge system.

    PubMed

    Cai, Bijing; Xie, Li; Yang, Dianhai; Arcangeli, Jean-Pierre

    2010-05-15

    The gaps of data for evaluating toxicity of new or overloaded organic chemicals on activated sludge system resulted in the requirements for methodology of toxicity estimation. In this study, 24 aromatic chemicals typically existed in the industrial wastewater were selected and classified into three groups of benzenes, phenols and anilines. Their toxicity on activated sludge was then investigated. Two indexes of IC(50-M) and IC(50-S) were determined respectively from the respiration rates of activated sludge with different toxicant concentration at mid-term (24h) and short-term (30min) time intervals. Experimental results showed that the group of benzenes was the most toxic, followed by the groups of phenols and anilines. The values of IC(50-M) of the tested chemicals were higher than those of IC(50-S). In addition, quantitative structure-activity relationships (QSARs) models developed from IC(50-M) were more stable and accurate than those of IC(50-S). The multiple linear models based on molecular descriptors and K(ow) presented better reliability than single linear models based on K(ow). Among these molecular descriptors, E(lumo) was the most important impact factor for evaluation of mid-term toxicity. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  4. Research to Support the Determination of Spacecraft Maximum Acceptable Concentrations of Potential Atmospheric Contaminants

    NASA Technical Reports Server (NTRS)

    Orr, John L.

    1997-01-01

    In many ways, the typical approach to the handling of bibliographic material for generating review articles and similar manuscripts has changed little since the use of xerographic reproduction has become widespread. The basic approach is to collect reprints of the relevant material and place it in folders or stacks based on its dominant content. As the amount of information available increases with the passage of time, the viability of this mechanical approach to bibliographic management decreases. The personal computer revolution has changed the way we deal with many familiar tasks. For example, word processing on personal computers has supplanted the typewriter for many applications. Similarly, spreadsheets have not only replaced many routine uses of calculators but have also made possible new applications because the cost of calculation is extremely low. Objective The objective of this research was to use personal computer bibliographic software technology to support the determination of spacecraft maximum acceptable concentration (SMAC) values. Specific Aims The specific aims were to produce draft SMAC documents for hydrogen sulfide and tetrachloroethylene taking maximum advantage of the bibliographic software.

  5. Gossypol Toxicity from Cottonseed Products

    PubMed Central

    Gadelha, Ivana Cristina N.; Fonseca, Nayanna Brunna S.; Oloris, Silvia Catarina S.; Melo, Marília M.

    2014-01-01

    Gossypol is a phenolic compound produced by pigment glands in cotton stems, leaves, seeds, and flower buds (Gossypium spp.). Cottonseed meal is a by-product of cotton that is used for animal feeding because it is rich in oil and proteins. However, gossypol toxicity limits cottonseed use in animal feed. High concentrations of free gossypol may be responsible for acute clinical signs of gossypol poisoning which include respiratory distress, impaired body weight gain, anorexia, weakness, apathy, and death after several days. However, the most common toxic effects is the impairment of male and female reproduction. Another important toxic effect of gossypol is its interference with immune function, reducing an animal's resistance to infections and impairing the efficiency of vaccines. Preventive procedures to limit gossypol toxicity involve treatment of the cottonseed product to reduce the concentration of free gossypol with the most common treatment being exposure to heat. However, free gossypol can be released from the bound form during digestion. Agronomic selection has produced cotton varieties devoid of glands producing gossypol, but these varieties are not normally grown because they are less productive and are more vulnerable to attacks by insects. PMID:24895646

  6. Quantifying loading, toxic concentrations, and systemic persistence of chloride in a contemporary mixed-land-use watershed using an experimental watershed approach.

    PubMed

    Hubbart, J A; Kellner, E; Hooper, L W; Zeiger, S

    2017-03-01

    A nested-scale experimental watershed study was implemented to quantify loading and persistence of chloride in an urbanizing, mixed-land-use watershed. A Midwest USA (Missouri) watershed was partitioned into five sub-basins with contrasting dominant land use. Streamwater was tested for chloride concentration four days per week from October 2009 through May 2014 at each site. Monitoring sites included co-located gauging and climate stations recording variables at 30-minute intervals. Results indicate significant (p<0.01) differences in chloride concentrations and loading between sites. Loading consistently increased from the forested headwaters (average=507kgday -1 ) to primarily urban watershed terminus (average=7501kgday -1 ). Chloride concentrations were highest (average=83.9mgL -1 ) with the greatest frequency of acutely toxic conditions (i.e. 860mgL -1 ) mid-watershed. This finding is in-part attributable to the ratio of chloride application to streamflow volume (i.e. increasing flow volume with stream distance resulted in chloride dilution, offsetting increased percent urban land use with stream distance). Results highlight the important, yet often confounding, interactions between pollutant loading and flow dynamics. Chloride peaks occurred during late winter/early spring melting periods, implicating road salt application as the primary contributor to the chloride regime. Floodplain groundwater analysis indicated seasonal sink/source relationships between the stream and floodplain, which could contribute to chronic toxicity and persistent low Cl - concentrations in streamwater year-round. Results hold important implications for resource managers wishing to mitigate water quality and aquatic habitat degradation, and suggest important water quality limitations to stream restoration success in complex urban aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Spacecraft Maximum Allowable Concentrations for Airborne Contaminants

    NASA Technical Reports Server (NTRS)

    James, John T.

    2008-01-01

    The enclosed table lists official spacecraft maximum allowable concentrations (SMACs), which are guideline values set by the NASA/JSC Toxicology Group in cooperation with the National Research Council Committee on Toxicology (NRCCOT). These values should not be used for situations other than human space flight without careful consideration of the criteria used to set each value. The SMACs take into account a number of unique factors such as the effect of space-flight stress on human physiology, the uniform good health of the astronauts, and the absence of pregnant or very young individuals. Documentation of the values is given in a 5 volume series of books entitled "Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants" published by the National Academy Press, Washington, D.C. These books can be viewed electronically at http://books.nap.edu/openbook.php?record_id=9786&page=3. Short-term (1 and 24 hour) SMACs are set to manage accidental releases aboard a spacecraft and permit risk of minor, reversible effects such as mild mucosal irritation. In contrast, the long-term SMACs are set to fully protect healthy crewmembers from adverse effects resulting from continuous exposure to specific air pollutants for up to 1000 days. Crewmembers with allergies or unusual sensitivity to trace pollutants may not be afforded complete protection, even when long-term SMACs are not exceeded. Crewmember exposures involve a mixture of contaminants, each at a specific concentration (C(sub n)). These contaminants could interact to elicit symptoms of toxicity even though individual contaminants do not exceed their respective SMACs. The air quality is considered acceptable when the toxicity index (T(sub grp)) for each toxicological group of compounds is less than 1, where T(sub grp), is calculated as follows: T(sub grp) = C(sub 1)/SMAC(sub 1) + C(sub 2/SMAC(sub 2) + ...+C(sub n)/SMAC(sub n).

  8. Acute toxicity and associated mechanisms of four strobilurins in algae.

    PubMed

    Liu, Xiaoxu; Wang, Yu; Chen, Hao; Zhang, Junli; Wang, Chengju; Li, Xuefeng; Pang, Sen

    2018-06-01

    Strobilurins have been reported highly toxic to non-target aquatic organisms but few illustrated how they cause toxic effects on algae. This study investigated the acute toxicity of Kresoxim-methy (KRE), Pyraclostrobin (PYR), Trifloxystrobin (TRI) and Picoxystrobin (PIC) on two algae and their toxicity mechanisms. Four strobilurins showed lower toxic effects on Chlorella pyrenoidsa but higher on Chlorella vulgaris. bc1 complex activities in C. vulgaris were significantly inhibited by all strobilurins, suggesting bc 1 complex might be the target of strobilurin toxicity in algae. Moreover, SOD, CAT and POD activities were significantly up-regulated by all doses of KRE, PYR and PIC. In contrast, low concentrations of TRI stimulated SOD and POD activities but highest concentration significantly inhibited those activities. Comet assays showed damaged DNA in C. vulgaris by four strobulirins, suggesting their potential genotoxic threats to algae. The results illustrated acute toxicity by strobulirins on algae and their possible toxicity mechanisms. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Pollutant Concentrations and Toxic Effects on the Red Alga Ceramium tenuicorne of Sediments from Natural Harbors and Small Boat Harbors on the West Coast of Sweden.

    PubMed

    Eklund, Britta; Hansson, Tomas; Bengtsson, Henrik; Eriksson Wiklund, Ann-Kristin

    2016-04-01

    This investigation set out to analyze the toxicity of surface sediments in a number of natural harbors and small boat harbors on the west coast of Sweden. This was done with the growth inhibition method with Ceramium tenuicorne. Also, concentrations of copper (Cu), lead (Pb), zinc (Zn), irgarol, organotin compounds, and polycyclic aromatic hydrocarbons (PAHs) in the sediments were analyzed. The small boat harbors were heavily polluted by Cu, Zn, butyltins, and PAHs, and to a lesser extent by Pb. The Cu, Pb, Zn, and butyltins probably originated from their past and/or present use in antifouling paints, whereas the PAHs probably had multiple sources, including boat motor exhausts. The measured toxicity of the sediment was generally related to their Cu, Zn, and butyltin content, although other toxic substances than those analyzed here probably contributed to the toxicity in some of the harbors. The natural harbor sediments contained less pollutants and were less toxic than the small boat harbor sediments. Nevertheless, our data indicate that the boating pressure today may be high enough to produce toxic effects even in natural harbors in pristine areas. The strongest relationship between toxicity and the major pollutants was obtained when the sediment toxicity was expressed as gram wet weight per liter compared with gram dry weight per liter and gram total organic carbon per liter. Hence, for pollutants that can be elutriated with natural sea water, sediment toxicity expressed as gram wet weight per liter appears preferable.

  10. Systemic toxicity of ropivacaine during ovine pregnancy.

    PubMed

    Santos, A C; Arthur, G R; Pedersen, H; Morishima, H O; Finster, M; Covino, B G

    1991-07-01

    Ropivacaine is a new amide local anesthetic structurally related to bupivacaine and mepivacaine. Its potency and duration of action are similar to those of bupivacaine but its therapeutic index may be greater. Since pregnancy enhances the cardiotoxicity of bupivacaine, the current study was devised to compare the toxicity of ropivacaine in chronically instrumented nonpregnant and pregnant ewes during continuous intravenous infusion of the drug at the rate of 0.5 mg.kg-1.min-1. In all animals, symptoms of local anesthetic toxicity occurred in the usual order--convulsions, hypotension, apnea, and circulatory collapse. There were no significant differences between the two groups of animals in the doses and plasma concentrations of ropivacaine associated with each toxic manifestations. For example, circulatory collapse occurred at a mean dose of 11.3 +/- 1.1 mg.kg-1 in nonpregnant and 12.4 +/- 0.9 mg.kg-1 in pregnant animals, with corresponding plasma concentrations of 7.3 +/- 0.3 and 9.6 +/- 2.1 micrograms.ml-1 (P = not significant). Protein binding of ropivacaine in the concentration range associated with toxic manifestations was similar in sera obtained from nonpregnant and pregnant ewes. In conclusion, ovine pregnancy does not enhance the systemic toxicity of ropivacaine, possibly because of an absence of gestation-related increase in the availability of free drug.

  11. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  12. COMMUNITY SCALE AIR TOXICS MODELING WITH CMAQ

    EPA Science Inventory

    Consideration and movement for an urban air toxics control strategy is toward a community, exposure and risk-based modeling approach, with emphasis on assessments of areas that experience high air toxic concentration levels, the so-called "hot spots". This strategy will requir...

  13. Photosynthetic and cellular toxicity of cadmium in Chlorella vulgaris.

    PubMed

    Ou-Yang, Hui-Ling; Kong, Xiang-Zhen; Lavoie, Michel; He, Wei; Qin, Ning; He, Qi-Shuang; Yang, Bin; Wang, Rong; Xu, Fu-Liu

    2013-12-01

    The toxic effects of cadmium (Cd) on the green alga Chlorella vulgaris were investigated by following the response to Cd of various toxicity endpoints (cell growth, cell size, photochemical efficiency of PSII in the light or Φ(PSII), maximal photochemical efficiency or Fv/Fm, chlorophyll a fluorescence, esterase activity, and cell viability). These toxicity endpoints were studied in laboratory batch cultures of C. vulgaris over a long-term 96-h exposure to different Cd concentrations using flow cytometry and pulse amplitude modulated fluorometry. The sequence of sensitivity of these toxicity endpoints was: cell yield > Φ(PSII) ≈ esterase activity > Fv/Fm > chlorophyll a fluorescence ≈ cell viability. It is shown that cell apoptosis or cell death only accounted for a minor part of the reduction in cell yield even at very high algistatic free Cd²⁺ concentrations, and other mechanisms such as blocked cell divisions are major contributors to cell yield inhibition. Furthermore, cadmium may affect both the electron donors and acceptors of the electron transport chain at high free Cd²⁺ concentration. Finally, the resistance of cells to cell death was size-dependent; medium-sized cells had the highest toxicity threshold. The present study brings new insights into the toxicity mechanisms of Cd in C. vulgaris and provides a detailed comparison of the sensitivity of various Cd toxicity endpoints. © 2013 SETAC.

  14. Yellow phosphorus process to convert toxic chemicals to non-toxic products

    DOEpatents

    Chang, S.G.

    1994-07-26

    The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O[sub 3], PO, PO[sub 2], etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like. 20 figs.

  15. Yellow phosphorus process to convert toxic chemicals to non-toxic products

    DOEpatents

    Chang, Shih-Ger

    1994-01-01

    The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O.sub.3, PO, PO.sub.2, etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like.

  16. Variations in toxicity of semi-coking wastewater treatment processes and their toxicity prediction.

    PubMed

    Ma, Xiaoyan; Wang, Xiaochang; Liu, Yongjun; Gao, Jian; Wang, Yongkun

    2017-04-01

    Chemical analyses and bioassays using Vibrio fischeri and Daphnia magna were conducted to evaluate comprehensively the variation of biotoxicity caused by contaminants in wastewater from a semi-coking wastewater treatment plant (WWTP). Pretreatment units (including an oil-water separator, a phenols extraction tower, an ammonia stripping tower, and a regulation tank) followed by treatment units (including anaerobic-oxic treatment units, coagulation-sedimentation treatment units, and an active carbon adsorption column) were employed in the semi-coking WWTP. Five benzenes, 11 phenols, and five polycyclic aromatic hydrocarbons (PAHs) were investigated as the dominant contaminants in semi-coking wastewater. Because of residual extractant, the phenols extraction process increased acute toxicity to V. fischeri and immobilization and lethal toxicity to D. magna. The acute toxicity of pretreated wastewater to V. fischeri was still higher than that of raw semi-coking wastewater, even though 90.0% of benzenes, 94.8% of phenols, and 81.0% of PAHs were removed. After wastewater pretreatment, phenols and PAHs were mainly removed by anaerobic-oxic and coagulation-sedimentation treatment processes respectively, and a subsequent active carbon adsorption process further reduced the concentrations of all target chemicals to below detection limits. An effective biotoxicity reduction was found during the coagulation-sedimentation and active carbon adsorption treatment processes. The concentration addition model can be applied for toxicity prediction of wastewater from the semi-coking WWTP. The deviation between the measured and predicted toxicity results may result from the effects of compounds not detectable by instrumental analyses, the synergistic effect of detected contaminants, or possible transformation products. Copyright © 2016. Published by Elsevier Inc.

  17. Comparative toxicant sensitivity of sexual and asexual reproduction in the rotifer Brachionus calyciflorus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Snell, T.W.; Carmona, M.J.

    Cyclically parthenogenetic zooplankters like rotifers are important tools for assessing toxicity in aquatic environments. Sexual reproduction is an essential component of rotifer life cycles, but current toxicity tests utilize only asexual reproduction. The authors compared the effects of four toxicants on asexual and sexual reproduction of the rotifer Brachionus calyciflorus. Toxicants had a differential effect on sexual and asexual reproduction, with sexual reproduction consistently the most sensitive. Concentrations of 0.2 {mu}g/ml PCP (sodium pentachlorophenate) had no effect on the asexual reproductive rate, but significantly reduced sexual reproduction. Likewise, chlorpyrifos concentrations of 0.3 {mu}g/ml had no significant effect on asexual reproduction,more » but sexual reproduction was significantly reduced. There was no difference in NOECs, LOECs, and chronic values for asexual and sexual reproduction for cadmium and naphthol tests. However, comparison of toxicant effect levels revealed that sexual reproduction was more strongly reduced at each toxicant concentration. The four toxicants tested inhibited sexual reproduction 2 to 68 times more than asexual reproduction at the lowest observed effect concentrations. Toxicants inhibited sexual reproduction in its initial step: sexual female production. Because sexual reproduction is more sensitive, toxicity tests based exclusively on asexual reproduction may not be protective of rotifer life cycles.« less

  18. The acute toxicity of major ion salts to Ceriodaphnia dubia: I. ...

    EPA Pesticide Factsheets

    The ions Na+, K+, Ca2+, Mg2+, Cl-, SO42-, and HCO3-/CO32- (referred to as “major ions”) are present in all fresh waters and are physiologically required by aquatic organisms, but can be increased to harmful levels by a variety of anthropogenic activities that speed geochemical weathering or otherwise introduce or concentrate ions. While toxicity of these ions to aquatic organisms has been previously shown, it is also known that their toxicity can vary depending on the concentrations of other co-occurring anions, and understanding these relationships is key to predicting toxicity and establishing appropriate environmental limits. In this paper we conduct a series of experiments with Ceriodaphnia dubia to evaluate the acute toxicity of all twelve major ionsalts (pairing one of the cations with one of the anions) and to determine how toxicity of these salts varies as a function of background water chemistry. All salts except CaSO4 and CaCO3 were acutely toxic to C. dubia below saturation, with the lowest LC50s found for K salts. Of the remaining salts, all but CaCl2 showed some degree of decreased toxicity as the ionic content of the background water increased. Experiments that independently varied Ca:Mg ratio, Na:K ratio, Cl:SO4 ratio, and alkalinity/pH were used to show that Ca concentration was the primary factor influencing the toxicities of Na and Mg salts. In contrast, the toxicities of K salts were primarily influenced by the concentration of Na. Th

  19. Evaluation of phase II toxicity identification evaluation methods for freshwater whole sediment and interstitial water.

    PubMed

    Phillips, Bryn M; Anderson, Brian S; Hunt, John W; Clark, Sara L; Voorhees, Jennifer P; Tjeerdema, Ron S; Casteline, Jane; Stewart, Margaret

    2009-02-01

    Phase I whole sediment toxicity identification evaluation (TIE) methods have been developed to characterize the cause of toxicity as organic chemicals, metals, or ammonia. In Phase II identification treatments, resins added to whole sediment to reduce toxicity caused by metals and organics can be separated and eluted much like solid-phase extraction (SPE) columns are eluted for interstitial water. In this study, formulated reference sediments spiked with toxic concentrations of copper, fluoranthene, and nonylphenol were subjected to whole sediment and interstitial water TIE treatments to evaluate Phase I and II TIE procedures for identifying the cause of toxicity to Hyalella azteca. Phase I TIE treatments consisted of adding adsorbent resins to whole sediment, and using SPE columns to remove spiked chemicals from interstitial water. Phase II treatments consisted of eluting resins and SPE columns and the preparation and testing of eluates for toxicity and chemistry. Whole sediment resins and SPE columns significantly reduced toxicity, and the eluates from all treatments contained toxic concentrations of the spiked chemical except for interstitial water fluoranthene. Toxic unit analysis based on median lethal concentrations (LC50s) allowed for the comparison of chemical concentrations among treatments, and demonstrated that the bioavailability of some chemicals was reduced in some samples and treatments. The concentration of fluoranthene in the resin eluate closely approximated the original interstitial water concentration, but the resin eluate concentrations of copper and nonylphenol were much higher than the original interstitial water concentrations. Phase II whole sediment TIE treatments provided complementary lines of evidence to the interstitial water TIE results.

  20. Toxicity and Metabolism of Layered Double Hydroxide Intercalated with Levodopa in a Parkinson’s Disease Model

    PubMed Central

    Kura, Aminu Umar; Ain, Nooraini Mohd; Hussein, Mohd Zobir; Fakurazi, Sharida; Hussein-Al-Ali, Samer Hasan

    2014-01-01

    Layered hydroxide nanoparticles are generally biocompatible, and less toxic than most inorganic nanoparticles, making them an acceptable alternative drug delivery system. Due to growing concern over animal welfare and the expense of in vivo experiments both the public and the government are interested to find alternatives to animal testing. The toxicity potential of zinc aluminum layered hydroxide (ZAL) nanocomposite containing anti-Parkinsonian agent may be determined using a PC 12 cell model. ZAL nanocomposite demonstrated a decreased cytotoxic effect when compared to levodopa on PC12 cells with more than 80% cell viability at 100 μg/mL compared to less than 20% cell viability in a direct levodopa exposure. Neither levodopa-loaded nanocomposite nor the un-intercalated nanocomposite disturbed the cytoskeletal structure of the neurogenic cells at their IC50 concentration. Levodopa metabolite (HVA) released from the nanocomposite demonstrated the slow sustained and controlled release character of layered hydroxide nanoparticles unlike the burst uptake and release system shown with pure levodopa treatment. PMID:24722565

  1. Relative potency estimates of acceptable residues and reentry intervals after nerve agent release

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Watson, A.P.; Jones, T.D.; Adams, J.D.

    1992-06-01

    In the event of an unplanned release of a chemical warfare agent during any stage of the Chemical Stockpile Disposal Program, the potential exists for off-post contamination of drinking water, forage crops, grains, garden produce, and livestock. The more persistent agents, such as the organophosphate nerve agent VX, pose the greatest human health concern for reentry. A relative potency approach comparing the toxicity of VX to organophosphate insecticide analogues is developed and used to estimate allowable residues for VX in agricultural products and reentry intervals for public access to contaminated areas. Analysis of mammalian LD50 data by all exposure routesmore » indicates that VX is 10(3) to 10(4) times more toxic than most commercially available organophosphate insecticides. Thus, allowable residues of VX could be considered at concentration levels 10(3) to 10(4) lower than those established for certain insecticides by the U.S. EPA. Evaluation of reentry intervals developed for these organophosphate analogues indicate that, if environmental monitoring cannot reliably demonstrate acceptable levels of VX, restricted access to suspect or contaminated areas may be on the order of weeks to months following agent release. Planning for relocation, mass care centers, and quarantine should take this time period into account.« less

  2. Variability of LD50 Values from Rat Oral Acute Toxicity Studies: Implications for Alternative Model Development

    EPA Science Inventory

    Alternative models developed for estimating acute systemic toxicity are generally evaluated using in vivo LD50 values. However, in vivo acute systemic toxicity studies can produce variable results, even when conducted according to accepted test guidelines. This variability can ma...

  3. Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation.

    PubMed

    Sydow, Mateusz; Owsianiak, Mikołaj; Framski, Grzegorz; Woźniak-Karczewska, Marta; Piotrowska-Cyplik, Agnieszka; Ławniczak, Łukasz; Szulc, Alicja; Zgoła-Grześkowiak, Agnieszka; Heipieper, Hermann J; Chrzanowski, Łukasz

    2018-01-01

    Little is known about the effect of ionic liquids (ILs) on the structure of soil microbial communities and resulting biodiversity. Therefore, we studied the influence of six trihexyl(tetradecyl)phosphonium ILs (with either bromide or various organic anions) at sublethal concentrations on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs where biodegradation extent was higher than 80%. (i.e. [P 66614 ][Br] and [P 66614 ][2,4,4]). Despite this general decrease in biodiversity, which can be explained by ecotoxic effect of the ILs, the microbial community in the microcosms was enriched with Gram-negative hydrocarbon-degrading genera e.g. Sphingomonas. It is hypothesized that, in addition to toxicity, the observed decrease in biodiversity and change in the microbial community structure may be explained by the primary biodegradation of the ILs or their metabolites by the mentioned genera, which outcompeted other microorganisms unable to degrade ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Non-animal Replacements for Acute Toxicity Testing.

    PubMed

    Barker-Treasure, Carol; Coll, Kevin; Belot, Nathalie; Longmore, Chris; Bygrave, Karl; Avey, Suzanne; Clothier, Richard

    2015-07-01

    Current approaches to predicting adverse effects in humans from acute toxic exposure to cosmetic ingredients still heavily necessitate the use of animals under EU legislation, particularly in the context of the REACH system, when cosmetic ingredients are also destined for use in other industries. These include the LD50 test, the Up-and-Down Procedure and the Fixed Dose Procedure, which are regarded as having notable scientific deficiencies and low transferability to humans. By expanding on previous in vitro tests, such as the animal cell-based 3T3 Neutral Red Uptake (NRU) assay, this project aims to develop a truly animal-free predictive test for the acute toxicity of cosmetic ingredients in humans, by using human-derived cells and a prediction model that does not rely on animal data. The project, funded by Innovate UK, will incorporate the NRU assay with human dermal fibroblasts in animal product-free culture, to generate an in vitro protocol that can be validated as an accepted replacement for the currently available in vivo tests. To date, the project has successfully completed an assessment of the robustness and reproducibility of the method, by using sodium lauryl sulphate (SLS) as a positive control, and displaying analogous results to those of the original studies with mouse 3T3 cells. Currently, the testing of five known ingredients from key groups (a surfactant, a preservative, a fragrance, a colour and an emulsifier) is under way. The testing consists of initial range-finding runs followed by three valid runs of a main experiment with the appropriate concentration ranges, to generate IC50 values. Expanded blind trials of 20 ingredients will follow. Early results indicate that this human cell-based test holds the potential to replace aspects of in vivo animal acute toxicity testing, particularly with reference to cosmetic ingredients. 2015 FRAME.

  5. [Iron concentration and acceptation of yoghurt prepared in casting iron pots (iron migration and acceptation of yogurt)].

    PubMed

    Quintaes, Késia Diego; Almeyda Haj-Isa, Niurka M; Morgano, Marcelo Antônio

    2005-12-01

    Food fortification is an interesting strategy to treat and prevent iron anemia. This study aims to quantify the iron in yoghurt, with gelatin and sugar and without, prepared in iron and glass containers. Sensorial test was use to evaluate the acceptance and preference of the both products. The yoghurt was prepared in containers of iron and glass with UHT milk, powder milk and natural industrialized yoghurt. After fermentation, half of the product received addition of sugar and strawberry flavor gelatin. The collected samples get the total iron quantified by ICP OES. Sensorial analysis involving 105 consumers was use to determine the acceptance and preference of the products. 0,018 and 0,882mg of iron per 100g added in the natural yoghurt prepared in the glass and in the iron pots, respectively. The yoghurt with gelatin presented 0,037 and 1,302mg of iron per 100g when prepared in the glass and in the iron pots, respectively. The preference was low for the yoghurt prepared in the iron pot (29,5%), but when added strawberry gelatin it was about 51,5%. The yoghurt prepared in iron pots, is easily home made and adds important amount of iron. Add gelatin and sugar can favored its consumption.

  6. Aquatic toxicity of nine aircraft deicer and anti-icer formulations and relative toxicity of additive package ingredients alkylphenol ethoxylates and 4,5-methyl-1H-henzotriazoles.

    PubMed

    Corsi, Steven R; Geis, Steven W; Loyo-Rosales, Jorge E; Rice, Clifford P

    2006-12-01

    Characterization of the effects of aircraft deicer and anti-icer fluid (ADAF) runoff on aquatic organisms in receiving streams is a complex issue because the identities of numerous toxic additives are proprietary and not publicly available. Most potentially toxic and endocrine disrupting effects caused by ADAF are due to the numerous additive package ingredients which vary among manufacturers and types of ADAF formulation. Toxicity investigations of nine ADAF formulations indicate that endpoint concentrations for formulations of different manufacturers are widely variable. Type IV ADAF (anti-icers) are more toxic than Type I (deicers) for the four organisms tested (Vibrio fischeri, Pimephales promelas, Ceriodaphnia dubia, and Selenastrum capricornutum). Acute toxicity endpoint concentrations ranged from 347 to 7700 mg/L as ADAF for Type IV and from 1550 to 45,100 mg/L for Type I formulations. Chronic endpoint concentrations ranged from 70 to 1300 mg/L for Type IV and from 37 to 18,400 mg/L for Type I formulations. Alkylphenol ethoxylates and tolyltriazoles are two known classes of additives. Nonylphenol, nonylphenol ethoxylates, octylphenol, octylphenol ethoxylates, and 4,5-methyl-1H-benzotriazoles were quantified in the nine ADAF formulations, and toxicity tests were conducted with nonylphenol ethoxylates and 4,5-methyl-1H-benzotriazoles. Toxicity units computed for glycol and these additives, with respect to toxicity of the ADAF formulations, indicate that a portion of ADAF toxicity can be explained by the known additives and glycols, but much of the toxicity is due to unidentified additives.

  7. Toxic trace elements at gastrointestinal level.

    PubMed

    Vázquez, M; Calatayud, M; Jadán Piedra, C; Chiocchetti, G M; Vélez, D; Devesa, V

    2015-12-01

    Many trace elements are considered essential [iron (Fe), zinc (Zn), copper (Cu)], whereas others may be harmful [lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As)], depending on their concentration and chemical form. In most cases, the diet is the main pathway by which they enter our organism. The presence of toxic trace elements in food has been known for a long time, and many of the food matrices that carry them have been identified. This has led to the appearance of legislation and recommendations concerning consumption. Given that the main route of exposure is oral, passage through the gastrointestinal tract plays a fundamental role in their entry into the organism, where they exert their toxic effect. Although the digestive system can be considered to be of crucial importance in their toxicity, in most cases we do not know the events that occur during the passage of these elements through the gastrointestinal tract and of ascertaining whether they may have some kind of toxic effect on it. The aim of this review is to summarize available information on this subject, concentrating on the toxic trace elements that are of greatest interest for organizations concerned with food safety and health: Pb, Cd, Hg and As. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Albendazole Induced Recurrent Acute Toxic Hepatitis: A Case Report.

    PubMed

    Bilgic, Yilmaz; Yilmaz, Cengiz; Cagin, Yasir Furkan; Atayan, Yahya; Karadag, Nese; Harputluoglu, Murat Muhsin Muhip

    2017-01-01

    Drug induced acute toxic hepatitis can be idiosyncratic. Albendazole, a widely used broad spectrum antiparasitic drug is generally accepted as a safe drug. It may cause asymptomatic transient liver enzyme abnormalities but acute toxic hepatitis is very rare. Case Report : Herein, we present the case of 47 year old woman with recurrent acute toxic hepatitis after a single intake of albendazole in 2010 and 2014. The patient was presented with symptoms and findings of anorexia, vomiting and jaundice. For diagnosis, other acute hepatitis etiologies were excluded. Roussel Uclaf Causality Assessment Method (RUCAM) score was calculated and found to be 10, which meant highly probable drug hepatotoxicity. Within 2 months, all pathological findings came to normal. There are a few reported cases of albendazole induced toxic hepatitis, but at adults, there is no known recurrent acute toxic hepatitis due to albendazole at this certainty according to RUCAM score. Physicians should be aware of this rare and potentially fatal adverse effect of albendazole. © Acta Gastro-Enterologica Belgica.

  9. Toxic Hazards Research Unit 1989

    DTIC Science & Technology

    1990-10-01

    frequently be developed to drive the experimental design and to assist in risk avsessments. The Toxic Hazards Division, Harry G. Armstrong Aerospace...postexposure, respectively. The experimental design (Section 3.3, Subchronic Inhalation Toxicity Studies on 3.1 Oil at Concentrations of 250, 50, and...sodium salt and the pH was adjusted to 7.4. 101 EXPERIMENTAL DESIGN Initiation Assessment A total of seven groups consisting of eight animals per

  10. Copper toxicity in aquaculture: A practical approach

    USDA-ARS?s Scientific Manuscript database

    Copper sulfate is used as a therapeutant for various applications in aquaculture. There is a great deal of information on the toxicity of copper, especially in low-alkalinity waters; however, much of this information is fragmented, and a comprehensive guide of copper toxicity and safe concentration...

  11. Serotonin toxicity involving MDMA (ecstasy) and moclobemide.

    PubMed

    Pilgrim, J L; Gerostamoulos, D; Woodford, N; Drummer, Olaf H

    2012-02-10

    The use of MDMA (ecstasy) in Australia is a widespread and growing problem, promoting acute toxicity and disease which can lead to premature death in users. We report four cases of fatal serotonin toxicity caused by the combination of MDMA and moclobemide, a reversible MAO-A inhibitor with potent serotonergic activity. Despite the highly reported toxicity of this drug combination, there are very few reports of fatalities attributed to a MDMA and moclobemide interaction. Pathology and toxicology reports, initial police reports and coroners' findings were examined to determine the circumstances of the deaths. Symptoms of some of the four cases as reported by paramedics and medical staff included hyperthermia, hyperkalemia, profuse sweating, twitching and shaking. Two cases involved moclobemide concentrations consistent with common prescribed doses, while the other two cases involved much higher concentrations often associated with toxicity. Three of these cases presented with some form of heart disease. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Comprehensive assessment of a chlorinated drinking water concentrate in a rat multigenerational reproductive toxicity study.

    PubMed

    Narotsky, Michael G; Klinefelter, Gary R; Goldman, Jerome M; Best, Deborah S; McDonald, Anthony; Strader, Lillian F; Suarez, Juan D; Murr, Ashley S; Thillainadarajah, Inthirany; Hunter, E Sidney; Richardson, Susan D; Speth, Thomas F; Miltner, Richard J; Pressman, Jonathan G; Teuschler, Linda K; Rice, Glenn E; Moser, Virginia C; Luebke, Robert W; Simmons, Jane Ellen

    2013-09-17

    Some epidemiological studies report associations between drinking water disinfection byproducts (DBPs) and adverse reproductive/developmental effects, e.g., low birth weight, spontaneous abortion, stillbirth, and birth defects. Using a multigenerational rat bioassay, we evaluated an environmentally relevant "whole" mixture of DBPs representative of chlorinated drinking water, including unidentified DBPs as well as realistic proportions of known DBPs at low-toxicity concentrations. Source water from a water utility was concentrated 136-fold, chlorinated, and provided as drinking water to Sprague-Dawley rats. Timed-pregnant females (P0 generation) were exposed during gestation and lactation. Weanlings (F1 generation) continued exposures and were bred to produce an F2 generation. Large sample sizes enhanced statistical power, particularly for pup weight and prenatal loss. No adverse effects were observed for pup weight, prenatal loss, pregnancy rate, gestation length, puberty onset in males, growth, estrous cycles, hormone levels, immunological end points, and most neurobehavioral end points. Significant, albeit slight, effects included delayed puberty for F1 females, reduced caput epidydimal sperm counts in F1 adult males, and increased incidences of thyroid follicular cell hypertrophy in adult females. These results highlight areas for future research, while the largely negative findings, particularly for pup weight and prenatal loss, are notable.

  13. Analysis of mobile source air toxics (MSATs)–Near-Road VOC and carbonyl concentrations

    EPA Science Inventory

    Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, a subset of compounds are considered high priority due to their significant contribution to cancer and...

  14. Oxaliplatin-Related Ocular Toxicity

    PubMed Central

    Mesquida, Marina; Sanchez-Dalmau, Bernardo; Ortiz-Perez, Santiago; Pelegrín, Laura; Molina-Fernandez, Juan José; Figueras-Roca, Marc; Casaroli-Marano, Ricardo; Adán, Alfredo

    2010-01-01

    We report the case of a 52-year-old woman with advanced colorectal cancer who was treated with oxaliplatin on a FOLFOX schedule. After 3 cycles of chemotherapy, she started to complain of visual loss, altered color vision and neurological symptoms. Due to the suspicion of ocular and neurological toxicity, antineoplastic treatment was stopped. Her visual field showed a concentric bilateral scotoma and the electrooculogram test revealed severe impairment of the retinal pigment epithelium. Visual acuity, color vision and visual field recovered completely 8 months later, although electrooculogram remained abnormal. Ocular toxicity has been reported as an infrequent adverse event of oxaliplatin. Findings in this case indicate toxicity of this chemotherapeutic agent on the retinal pigment epithelium, which has not been reported before. This damage could be permanent, and it thus differs from previously described oxaliplatin-induced ocular toxicities, which are usually transient and reversible. With increasing use of oxaliplatin as first-line treatment in advanced colorectal cancer, we have to be aware of this possible toxicity. PMID:21151636

  15. Essential and toxic element concentrations in blood and urine and their associations with diet: results from a Norwegian population study including high-consumers of seafood and game.

    PubMed

    Birgisdottir, B E; Knutsen, H K; Haugen, M; Gjelstad, I M; Jenssen, M T S; Ellingsen, D G; Thomassen, Y; Alexander, J; Meltzer, H M; Brantsæter, A L

    2013-10-01

    The first aim of the study was to evaluate calculated dietary intake and concentrations measured in blood or urine of essential and toxic elements in relation to nutritional and toxicological reference values. The second aim was to identify patterns of the element concentrations in blood and urine and to identify possible dietary determinants of the concentrations of these elements. Adults with a known high consumption of environmental contaminants (n=111), and a random sample of controls (n=76) answered a validated food frequency questionnaire (FFQ). Complete data on biological measures were available for 179 individuals. Blood and urine samples were analyzed for selenium, iodine, arsenic, mercury, cadmium and lead. Principal component analysis was used to identify underlying patterns of correlated blood and urine concentrations. The calculated intakes of selenium, iodine, inorganic arsenic and mercury were within guideline levels. For cadmium 24% of the high consumer group and 8% of the control group had intakes above the tolerable weekly intake. Concentrations of lead in blood exceeded the bench-mark dose lower confidence limits for some participants. However, overall, the examined exposures did not give rise to nutritional or toxicological concerns. Game consumption was associated with lead in blood (B(ln) 0.021; 95%CI:0.010, 0.031) and wine consumption. Seafood consumption was associated with urinary cadmium in non-smokers (B(ln) 0.009; 95%CI:0.003, 0.015). A novel finding was a distinct pattern of positively associated biological markers, comprising iodine, selenium, arsenic and mercury (eigenvalue 3.8), reflecting seafood intake (B 0.007; 95%CI:0.004, 0.010). The study clearly demonstrates the significance of seafood as a source of both essential nutrients and toxic elements simultaneously and shows that exposure to various essential and toxic elements can be intertwined. © 2013 Elsevier B.V. All rights reserved.

  16. A 7-d toxicity test for marine pollutants using the Pacific mysid Mysidopsis intii. 2: Protocol evaluation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Harmon, V.L.; Langdon, C.J.

    1996-10-01

    The sensitivity of the Pacific coast mysid Mysidopsis intii to pollutants was compared in 7-d toxicity tests with that of the Gulf coast mysid M. bahia and the Pacific coast mysid Holmesimysis costata. Survival and growth responses of M. intii to zinc (maximum acceptable toxicant concentration [MATC] survival and growth, 152 {micro}g/L) were as sensitive as survival of both M. bahia (MATC survival, 152 {micro}g/L) and H. costata (MATC survival, 152 {micro}g/L). In contrast, the 7-d test for M. intii was less sensitive (MATC growth and survival, 4.99 mg/L) than the test for H. costata (MATC survival, 1.99 mg/L) whenmore » sodium dodecyl sulfate (SDS) was used as the toxicant. Interlaboratory evaluation of the 7-d test for M. intii exposed to SDS indicated that the test was reliable. The mean test results for the group of participating laboratories were not significantly different from those of a group of three in-house tests, indicating that shipping and handling did not affect mysid sensitivity to SDS. Mysid growth was not as sensitive to SDS as survival in the interlaboratory tests. Although there were significant differences in median lethal concentration (LC50) values among participating laboratories, coefficients of variation of LC50 and MATC survival values among laboratories were 10.3 and 37%, respectively. These coefficients were comparable to those reported for interlaboratory tests with H. costata.« less

  17. Lead concentration in plasma as a biomarker of exposure and risk, and modification of toxicity by δ-aminolevulinic acid dehydratase gene polymorphism.

    PubMed

    Tian, Liting; Zheng, Guang; Sommar, Johan Nilsson; Liang, Yihuai; Lundh, Tomas; Broberg, Karin; Lei, Lijian; Guo, Weijun; Li, Yulan; Tan, Mingguang; Skerfving, Staffan; Jin, Taiyi; Bergdahl, Ingvar A

    2013-08-14

    Blood lead concentration (B-Pb), the main biomarker of lead exposure and risk, is curvi-linearily related to exposure. We assessed plasma lead (P-Pb) as a marker for both lead exposure and toxic effects. We examined claims that δ-aminolevulinic acid dehydratase genotype (ALAD) can modify lead toxicity. In 290 lead-exposed and 91 unexposed Chinese workers, we determined P-Pb, B-Pb, urinary lead (U-Pb), ALAD polymorphism (rs1800435, ALAD1/2; TaqMan assay), and also toxic effects on heme synthesis (blood zinc protoporphyrin and hemoglobin, urinary δ-aminolevulic acid), on the kidneys (urinary albumin, β2-microglobulin and N-acetyl-β-d-glucosaminidase) and on the peripheral nervous system (sensory and motor conduction velocities). In exposed workers, median P-Pb was 4.10 (range 0.35-27)μg/L, B-Pb 401 (110-950)μg/L, and U-Pb 188 (22-590)μg/g creatinine. P-Pb had a higher ratio between exposed and unexposed workers (median 39, range 18-110) than B-Pb (19, 15-36; p<0.001) and U-Pb (28, 15-36; p<0.001). All three biomarkers were associated with all toxic effects (P-Pb: rS=-0.10 to 0.79; B-Pb: rS=-0.08 to 0.75; all p<0.05). In the exposed workers, B-Pb and U-Pb were significantly higher (p=0.04) in ALAD2 carriers (7% in the exposed population) than in ALAD1 homozygotes. P-Pb values were similar; ALAD1 homozygotes suffered higher kidney toxicity at the same P-Pb. (i) P-Pb has advantages over B-Pb as a biomarker of high Pb exposure, but it was not significantly better as an index of risk of toxicity. (ii) The ALAD genotype modifies toxicokinetics and toxicodynamics. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Impacts of waste from concentrated animal feeding operations on water quality

    USGS Publications Warehouse

    Burkholder, J.; Libra, B.; Weyer, P.; Heathcote, S.; Kolpin, D.; Thorne, P.S.; Wichman, M.

    2007-01-01

    Waste from agricultural livestock operations has been a long-standing concern with respect to contamination of water resources, particularly in terms of nutrient pollution. However, the recent growth of concentrated animal feeding operations (CAFOs) presents a greater risk to water quality because of both the increased volume of waste and to contaminants that may be present (e.g., antibiotics and other veterinary drugs) that may have both environmental and public health importance. Based on available data, generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste. Impacts on surface water sources and wildlife have been documented in many agricultural areas in the United States. Potential impacts on human and environmental health from long-term inadvertent exposure to water contaminated with pharmaceuticals and other compounds are a growing public concern. This workgroup, which is part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards-Searching for Solutions, identified needs for rigorous ecosystem monitoring in the vicinity of CAFOs and for improved characterization of major toxicants affecting the environment and human health. Last, there is a need to promote and enforce best practices to minimize inputs of nutrients and toxicants from CAFOs into freshwater and marine ecosystems.

  19. Impacts of Waste from Concentrated Animal Feeding Operations on Water Quality

    PubMed Central

    Burkholder, JoAnn; Libra, Bob; Weyer, Peter; Heathcote, Susan; Kolpin, Dana; Thorne, Peter S.; Wichman, Michael

    2007-01-01

    Waste from agricultural livestock operations has been a long-standing concern with respect to contamination of water resources, particularly in terms of nutrient pollution. However, the recent growth of concentrated animal feeding operations (CAFOs) presents a greater risk to water quality because of both the increased volume of waste and to contaminants that may be present (e.g., antibiotics and other veterinary drugs) that may have both environmental and public health importance. Based on available data, generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste. Impacts on surface water sources and wildlife have been documented in many agricultural areas in the United States. Potential impacts on human and environmental health from long-term inadvertent exposure to water contaminated with pharmaceuticals and other compounds are a growing public concern. This work-group, which is part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards—Searching for Solutions, identified needs for rigorous ecosystem monitoring in the vicinity of CAFOs and for improved characterization of major toxicants affecting the environment and human health. Last, there is a need to promote and enforce best practices to minimize inputs of nutrients and toxicants from CAFOs into freshwater and marine ecosystems. PMID:17384784

  20. Sucrose acceptance, discrimination and proboscis responses of honey bees (Apis mellifera L.) in the field and the laboratory.

    PubMed

    Mujagic, Samir; Erber, Joachim

    2009-04-01

    Laboratory studies in honey bees have shown positive correlations between sucrose responsiveness, division of labour and learning. We tested the relationships between sucrose acceptance and discrimination in the field and responsiveness in the laboratory. Based on acceptance in the field three groups of bees were differentiated: (1) bees that accept sucrose concentrations >10%, (2) bees that accept some but not all of the sucrose concentrations <10% and water, and (3) bees that accept water and all offered sucrose concentrations. Sucrose acceptance can be described in a model in which sucrose- and water-dependent responses interact additively. Responsiveness to sucrose was tested in the same bees in the laboratory by measuring the proboscis extension response (PER). The experiments demonstrated that PER responsiveness is lower than acceptance in the field and that it is not possible to infer from the PER measurements in the laboratory those concentrations the respective bees accepted in the field. Discrimination between sucrose concentrations was tested in three groups of free-flying bees collecting low, intermediate or high concentrations of sucrose. The experiments demonstrated that bees can discriminate between concentrations differences down to 0.2 relative log units. There exist only partial correlations between discrimination, acceptance and PER responsiveness.

  1. Subchronic (13-week) toxicity and prenatal developmental toxicity studies of dietary astaxanthin in rats.

    PubMed

    Vega, Katherine; Edwards, James; Beilstein, Paul

    2015-12-01

    Two studies examined the effects of dietary astaxanthin on Hanlbm Wistar (SPF) rats. Male and female rats receiving astaxanthin concentrations up to 1.52% of the feed for 13 weeks showed no evidence of toxicity; no effects were noted in the offspring of female rats exposed to astaxanthin at up to 1.39% of the feed during the period of organogenesis (GD 7-16). Discoloration of the feces and yellow pigmentation of adipose tissue was seen in the 13-week study, an intrinsic property of the substance, and not a sign of toxicity. Differences between the control and astaxanthin groups, some of which reached statistical significance, were generally sporadic (i.e., transient and/or not related to astaxanthin concentration) and not considered of biological or toxicological significance. Blood cholesterol levels, for example, were greater in animals receiving astaxanthin for 13 weeks, but remained within the normal range. The highest dietary concentration of astaxanthin in each of the studies is proposed as a no-observable-adverse-effect level (NOAEL). Specifically, 1.52% for the 13-week study, corresponding to a mean intake of 1033 mg/kg bw/day (range: 880-1240 mg/kg bw/day), and 1.39% for the developmental toxicity study, corresponding to a mean intake of approximately 830 mg/kg bw/day (range: 457-957 mg/kg bw/day). Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Toxicity and repellency to rats of actidione

    USGS Publications Warehouse

    Traub, R.; DeWitt, J.B.; Welch, J.F.; Newman, D.

    1950-01-01

    The antibiotic actidione was found to be highly repellent to laboratory rats and to significantly reduce gnawing attacks upon treated paperboards. Rats refused to accept food or water containing this material even under conditions of acute starvation and died of starvation and thirst,rather than accept water containing l.0 mg. of actidione per liter. The compound is highly toxic to .rats with the minimum .lethal dose by oral administration being approximately l.0 mg./Kg body weight. Paperboard treated with the compound resisted gnawing attacks by specially trained and motivated rats for periods of two hundred hours, although similar .untreated boards were pierced within thirty-to sixty minutes.

  3. Pesticide toxicity index for freshwater aquatic organisms, 2nd edition

    USGS Publications Warehouse

    Munn, Mark D.; Gilliom, Robert J.; Moran, Patrick W.; Nowell, Lisa H.

    2006-01-01

    The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is designed to assess current water-quality conditions, changes in water quality over time, and the effects of natural and human factors on water quality for the Nation's streams and ground-water resources. For streams, one of the most difficult parts of the assessment is to link chemical conditions to effects on aquatic biota, particularly for pesticides, which tend to occur in streams as complex mixtures with strong seasonal patterns. A Pesticide Toxicity Index (PTI) was developed that combines pesticide exposure of aquatic biota (measured concentrations of pesticides in stream water) with acute toxicity estimates (standard endpoints from laboratory bioassays) to produce a single index value for a sample or site. The development of the PTI was limited to pesticide compounds routinely measured in NAWQA studies and to toxicity data readily available from existing databases. Qualifying toxicity data were found for one or more types of test organisms for 124 of the 185 pesticide compounds measured in NAWQA samples, but with a wide range of available bioassays per compound (1 to 232). In the databases examined, there were a total of 3,669 bioassays for the 124 compounds, including 398 48-hour EC50 values (concentration at which 50 percent of test organisms exhibit a sublethal response) for freshwater cladocerans, 699 96-hour LC50 values (concentration lethal to 50 percent of test organisms) for freshwater benthic invertebrates, and 2,572 96-hour LC50 values for freshwater fish. The PTI for a particular sample is the sum of toxicity quotients (measured concentration divided by the median toxicity concentration from bioassays) for each detected pesticide, and thus, is based on the concentration addition model of pesticide toxicity. The PTI can be calculated for specific groups of pesticides and for specific taxonomic groups. Although the PTI does not determine whether water in a sample is

  4. Assessment of Jatropha curcas L. biodiesel seed cake toxicity using the zebrafish (Danio rerio) embryo toxicity (ZFET) test.

    PubMed

    Hallare, Arnold V; Ruiz, Paulo Lorenzo S; Cariño, J C Earl D

    2014-05-01

    Consequent to the growing demand for alternative sources of energy, the seeds from Jatropha curcas remain to be the favorite for biodiesel production. However, a significant volume of the residual organic mass (seed cake) is produced during the extraction process, which raises concerns on safe waste disposal. In the present study, we assessed the toxicity of J. curcas seed cake using the zebrafish (Danio rerio) embryotoxicity test. Within 1-h post-fertilization (hpf), the fertilized eggs were exposed to five mass concentrations of J. curcas seed cake and were followed through 24, 48, and 72 hpf. Toxicity was evaluated based on lethal endpoints induced on zebrafish embryos namely egg coagulation, non-formation of somites, and non-detachment of tail. The lowest concentration tested, 1 g/L, was not able to elicit toxicity on embryos whereas 100 % mortality (based also on lethal endpoints) was recorded at the highest concentration at 2.15 g/L. The computed LC50 for the J. curcas seed cake was 1.61 g/L. No further increase in mortality was observed in the succeeding time points (48 and 72 hpf) indicating that J. curcas seed cake exerted acute toxicity on zebrafish embryos. Sublethal endpoints (yolk sac and pericardial edema) were noted at 72 hpf in zebrafish embryos exposed to higher concentrations. The observed lethal endpoints induced on zebrafish embryos were discussed in relation to the active principles, notably, phorbol esters that have remained in the seed cake even after extraction.

  5. Evaluation of soil toxicity at Joliet Army Ammunition Plant

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Simini, M.; Amos, J.C.; Wentsel, R.S.

    1995-04-01

    Environmental toxicity testing and chemical analyses of soil were performed as part of an ecological risk assessment at the Joliet Army Ammunition Plant (JAAP), Joliet, Illinois. Soils were collected from an area where munitions were loaded, assembled, and packed (area L7, group 1), and from an area where waste explosives were burned on unprotected soil (area L2). Control samples were collected from an adjacent field. Soil toxicity was determined using early seedling growth and vigor tests, earthworm survival and growth tests, and Microtox{reg_sign} assays. Relative toxicity of soils was determined within each area based on statistical significant (p = 0.05)more » of plant and earthworm growth and survival, and the effective concentration at which luminescence of the bacterium Photobacterium phosphoreum was reduced by 50% (EC50) in the Microtox assay. Samples were designated as having high, moderate, or no significant toxicity. Soil that had significant toxicity according to at least one test, and representative samples showing no toxicity, were analyzed for munitions via HPLC. Chemical residues found in soils were 2,4,6-trinitrotoluene (TNT); 1,3,5-trinitrobenzene (TNB); 2,4-dinitrotoluene (2,4-DNT); 2,6-dinitrotoluene; 2-amino-4,6-DNT; 4-amino-2,6-DNT; 1,3,5-trinitro-1,3,5-triazine (RDX); and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). All soils with no significant toxicity were void of these chemicals. However, some soils void of munitions still showed toxicity that may have been caused by elevated levels of heavy metals. Linear regressions of toxicity test results vs. chemical concentrations showed that TNT and TNB accounted for most off the soil toxicity. Lowest-observable-effect concentrations (LOEC) of TNT were determined from these data. This study presents a simple, relatively inexpensive methodology for assessing toxicity of soils containing TNT, RDX, and other contaminants related to munitions production.« less

  6. Study on acute toxicity of amoxicillin wastewater to Zebrafish

    NASA Astrophysics Data System (ADS)

    Xie, Weifang; Shen, Hongyan

    2017-12-01

    The main research in this paper is to obtain the effect of pharmaceutical wastewater on the acute toxicity of Zebrafish. The experimental method of exposure is used in this research. Experiments were carried out with different groups of pharmaceutical wastewater. Zebrafish was cultivated in a five liter fish tank. In the experiment, according to mortality, initially a 96h preliminary test was carried out at exposure concentrations to determine if the amoxicillin wastewater was toxic and to define the concentration range (24h LC100, 96h LC0) to be employed in the definitive tests. Based on the half lethal concentration of Zebrafish, the acute toxicity of amoxicillin wastewater to Zebrafish was calculated and the toxicity grade of wastewater was determined. In the experiment, the Zebrafish was exposed with amoxicillin wastewater during 96h. The 24h, 48h, 72h and 96h LC50 of amoxicillin wastewater on the Zebrafish were 63.10%, 53.70%, 41.69% and 40.74%, respectively. At 96h, the test time is the longest, and the value of LC50 is the smallest. In the observation period of 96 hours, the LC50 of amoxicillin wastewater were in the range of 40% ~ 60% and the value of Tua is 1 ~ 2. It indicates amoxicillin wastewater is low toxic wastewater when the experimental time is shorter than 48h, amoxicillin wastewater is moderate toxicity wastewater when the experimental time is higher than 48h. According to the experimental data, with the exposure time and the volume percentage of amoxicillin wastewater increases, the mortality rate of Zebrafish is gradually increased and the toxicity of amoxicillin wastewater increases. It indicates that the toxicity of amoxicillin wastewater is the biggest and the effect of wastewater on Zebrafish is greatest. In some ways, the toxicity of amoxicillin wastewater can be affected by the test time.

  7. Metal-Polycyclic Aromatic Hydrocarbon Mixture Toxicity in Hyalella azteca. 1. Response Surfaces and Isoboles To Measure Non-additive Mixture Toxicity and Ecological Risk.

    PubMed

    Gauthier, Patrick T; Norwood, Warren P; Prepas, Ellie E; Pyle, Greg G

    2015-10-06

    Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in aquatic environments, yet relatively little is known regarding their potential to produce non-additive toxicity (i.e., antagonism or potentiation). A review of the lethality of metal-PAH mixtures in aquatic biota revealed that more-than-additive lethality is as common as strictly additive effects. Approaches to ecological risk assessment do not consider non-additive toxicity of metal-PAH mixtures. Forty-eight-hour water-only binary mixture toxicity experiments were conducted to determine the additive toxic nature of mixtures of Cu, Cd, V, or Ni with phenanthrene (PHE) or phenanthrenequinone (PHQ) using the aquatic amphipod Hyalella azteca. In cases where more-than-additive toxicity was observed, we calculated the possible mortality rates at Canada's environmental water quality guideline concentrations. We used a three-dimensional response surface isobole model-based approach to compare the observed co-toxicity in juvenile amphipods to predicted outcomes based on concentration addition or effects addition mixtures models. More-than-additive lethality was observed for all Cu-PHE, Cu-PHQ, and several Cd-PHE, Cd-PHQ, and Ni-PHE mixtures. Our analysis predicts Cu-PHE, Cu-PHQ, Cd-PHE, and Cd-PHQ mixtures at the Canadian Water Quality Guideline concentrations would produce 7.5%, 3.7%, 4.4% and 1.4% mortality, respectively.

  8. Concentration of potentially toxic elements in field crops grown near and far from cities of the Pampas (Argentina).

    PubMed

    Lavado, Raúl S

    2006-07-01

    Soils of the Pampas show no signs of contamination with potentially toxic elements (PTEs), except in the areas that surround cities. The concentration of PTE in crops grown in this region is in most cases unknown. Our objective was to determine the PTE concentration in main field crops and pastures grown in 'a priori' non-contaminated areas and in potentially contaminated areas around cities. Forty-eight plots from farms located far from cities or roads and 36 plots from farms located very close to cities or to high traffic roads were sampled. The area ranged from 33 degrees 40' S to 36 degrees 0' S and from 57 degrees 35' W to 61 degrees 22' W. Maize, soybean, wheat, grazed grassland and pastures, and their top soils were sampled. All samples were acid digested. Cadmium, zinc, chromium, copper, nickel and lead were determined using ICPES. Standard t-tests were performed. All soils were within the known normal values of soil PTE concentrations, with the exception of a few cases around cities. PTE accumulation on grains and aerial biomass is considered almost negligible in crops grown in both studied areas, with the exception of a few elements in soybean. PTE concentrations in crops and pastures are in keeping with the low content of trace metals found in soils of the Pampas.

  9. The Role of Intestinal Microbiota in Development of Irinotecan Toxicity and in Toxicity Reduction through Dietary Fibres in Rats

    PubMed Central

    Lin, Xiaoxi B.; Farhangfar, Arazm; Valcheva, Rosica; Sawyer, Michael B.; Dieleman, Levinus; Schieber, Andreas; Gänzle, Michael G.; Baracos, Vickie

    2014-01-01

    CPT-11 is a drug used as chemotherapy for colorectal cancer. CPT-11 causes toxic side-effects in patients. CPT-11 toxicity has been attributed to the activity of intestinal microbiota, however, intestinal microbiota may also have protective effects in CP!-11 chemotherapy. This study aimed to elucidate mechanisms through which microbiota and dietary fibres could modify host health. Rats bearing a Ward colon carcinoma were treated with a two-cycle CPT-11/5-fluorouracil therapy recapitulating clinical therapy of colorectal cancer. Animals were fed with a semi-purified diet or a semi-purified diet was supplemented with non-digestible carbohydrates (isomalto-oligosaccharides, resistant starch, fructo-oligosaccharides, or inulin) in 3 independent experiments. Changes in intestinal microbiota, bacteria translocating to mesenteric lymphnodes, cecal GUD activity, and cecal SCFA production, and the intestinal concentration of CPT-11 and its metabolites were analysed. Non-digestible carbohydrates significantly influenced feed intake, body weight and other indicators of animal health. The identification of translocating bacteria and their quantification in cecal microbiota indicated that overgrowth of the intestine by opportunistic pathogens was not a major contributor to CPT-11 toxicity. Remarkably, fecal GUD activity positively correlated to body weight and feed intake but negatively correlated to cecal SN-38 concentrations and IL1-β. The reduction in CPT-11 toxicity by non-digestible carbohydrates did not correlate to stimulation of specific bacterial taxa. However, cecal butyrate concentrations and feed intake were highly correlated. The protective role of intestinal butyrate production was substantiated by a positive correlation of the host expression of MCT1 (monocarboxylate transporter 1) with body weight as well as a positive correlation of the abundance of bacterial butyryl-CoA gene with cecal butyrate concentrations. These correlations support the interpretation

  10. Toxicity of sediment-associated pesticides to Chironomus dilutus and Hyalella azteca.

    PubMed

    Ding, Yuping; Weston, Donald P; You, Jing; Rothert, Amanda K; Lydy, Michael J

    2011-07-01

    Two hundred sediment samples were collected and their toxicity evaluated to aquatic species in a previous study in the agriculturally dominated Central Valley of California, United States. Pyrethroid insecticides were the main contributors to the observed toxicity. However, mortality in approximately one third of the toxic samples could not be explained solely by the presence of pyrethroids in the matrices. Hundreds of pesticides are currently used in the Central Valley of California, but only a few dozen are analyzed in standard environmental monitoring. A significant amount of unexplained sediment toxicity may be due to pesticides that are in widespread use that but have not been routinely monitored in the environment, and even if some of them were, the concentrations harmful to aquatic organisms are unknown. In this study, toxicity thresholds for nine sediment-associated pesticides including abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin were established for two aquatic species, the midge Chironomus dilutus and the amphipod Hyalella azteca. For midges, the median lethal concentration (LC₅₀) of the pesticides ranged from 0.18 to 964 μg/g organic carbon (OC), with abamectin being the most toxic and propargite being the least toxic pesticide. A sublethal growth endpoint using average individual ash-free dry mass was also measured for the midges. The no-observable effect concentration values for growth ranged from 0.10 to 633 μg/g OC for the nine pesticides. For the amphipods, fenpropathrin was the most toxic, with an LC₅₀ of 1-2 μg/g OC. Abamectin, diazinon, and methyl parathion were all moderately toxic (LC₅₀s 2.8-26 μg/g OC). Dicofol, indoxacarb, oxyfluorfen, propargite, and pyraclostrobin were all relatively nontoxic, with LC₅₀s greater than the highest concentrations tested. The toxicity information collected in the present study will be helpful in decreasing the

  11. Oil and oil dispersant do not cause synergistic toxicity to fish embryos.

    PubMed

    Adams, Julie; Sweezey, Michael; Hodson, Peter V

    2014-01-01

    Atlantic herring (Clupea harengus) embryos were exposed to water accommodated fractions (WAFs; oil dissolved in water) and chemically enhanced water accommodated fractions (CEWAFs; oil dispersed in water with Corexit 9500A) of Medium South American (MESA) crude oil. The CEWAF was approximately 100-fold more toxic than WAF based on nominal loadings of test solutions (% v/v). In contrast, the ratio of WAF and CEWAF toxicity expressed as measured oil concentrations approximated 1.0, indicating that the higher toxicity of CEWAFs was caused by an increase in exposure to hydrocarbons with chemical dispersion. In a second experiment, the chronic toxicity of Corexit 9500A and chemically dispersed heavy fuel oil 7102 (HFO 7102) to rainbow trout (Oncorhynchus mykiss) embryos was compared to chemically dispersed Nujol, a nontoxic mineral oil. Dispersant alone was toxic, but caused different signs of toxicity than HFO 7102. Nujol at a dispersant-to-oil ratio of 1:20 was nontoxic, suggesting that dispersant was sequestered by oil and not present at toxic concentrations. In contrast, the same nominal loadings of dispersed HFO 7102 caused concentration-dependent increases in toxicity. Both experiments suggest that chemically dispersed oil was more toxic to fish embryos than solutions created by mechanical mixing due to the increased exposure of fish to petroleum hydrocarbons and not to changes in hydrocarbon toxicity. The Nujol control discriminated between the toxicity of oil and chemical dispersant and would be a practical addition to programs of dispersant testing.

  12. Lead toxicity.

    PubMed

    Gidlow, D A

    2015-07-01

    Since the last In-Depth Review of lead toxicity in 2004 there have been further developments with regard to safe exposure levels for lead workers. To advise occupational health professionals of the latest research on the multi-system toxic effects of lead and the implications of this research for setting new safe and appropriate occupational suspension limits. An extensive review of the current literature and an investigation of the database used by lead users to produce their submission under the REACH Regulations. Much of the published research on lead toxicity is on the effects of lead on the general population where blood lead levels are considerably lower than those seen in lead-exposed workers. It is always difficult to compare such studies with those undertaken on exposed workers as they may not be directly comparable and may not have taken into account all confounding variables and the well-acknowledged 'healthy worker' concept. However, it is clear that there is substantial evidence that potential health effects on lead workers may be seen at levels which were previously accepted as 'safe'. There is undoubtedly a narrow margin of safety between current occupational blood lead suspension limits and subclinical effect. As a result, the lead users have produced a voluntary Code of Practice with suspension limits significantly below those seen in some national legislation, particularly the Control of Lead at Work Act 2002. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Oxidative degradation of tetramethylammonium hydroxide (TMAH) by UV/persulfate and associated acute toxicity assessment.

    PubMed

    Huang, Jingting; Wang, Kai-Sung; Liang, Chenju

    2017-07-29

    Tetramethylammonium hydroxide (TMAH) is widely used in high-tech industries as a developing agent. Ultraviolet (UV) light-activated persulfate (PS, S 2 O 8 2- ) can be used to generate strongly oxidative sulfate radicals, and it also exhibits the potential to treat TMAH-containing wastewater. This study initially investigated the effect of S 2 O 8 2- concentration and UV strength on the UV/S 2 O 8 2- process for the degradation of TMAH in a batch reactor. The results suggested that 15 watts (W) of UV-activated S 2 O 8 2- at concentrations of 10 or 50 mM resulted in pseudo-first-order TMAH degradation rate constants of 3.1-4.2 × 10 -2 min -1 , which was adopted for determining the hydraulic retention time (HRT) in a continuous stirred tank reactor (CSTR). The operating conditions (15 W UV/10 mM S 2 O 8 2- ) with a HRT of 129 min resulted in stable residual concentrations of S 2 O 8 2- and TMAH at approximately 2.6 mM and 20 mg L -1 in effluent, respectively. Several TMAH degradation intermediates including trimethylamine, dimethylamine, and methylamine were also detected. The effluent was adjusted to a neutral pH and evaluated for its biological acute toxicity using Cyprinus carpio as a bioassay organism. The "bio-acute toxicity unit" (TU a ) was determined to be 1.41, which indicated that the effluent was acceptable for being discharged into an aquatic ecosystem.

  14. Discriminating toxicant classes by mode of action. 1. (Eco)toxicity profiles.

    PubMed

    Nendza, Monika; Wenzel, Andrea

    2006-05-01

    Predictive toxicology, particularly quantitative structure-activity relationships (QSARs), require classification of chemicals by mode of action (MOA). MOA is, however, not a constant property of a compound but it varies between species and may change with concentration and duration of exposure. A battery of MOA-specific in-vitro and low-complexity assays, featuring biomolecular targets for major classes of environmental pollutants, provides characteristic responses for (1.) classification of chemicals by MOA, (2.) identification of (eco)toxicity profiles of chemicals, (3.) identification of chemicals with specific MOAs, (4.) indication of most sensitive species, (5.) identification of chemicals that are outliers in QSARs and (6.) selection of appropriate QSARs for predictions. Chemicals covering nine distinct modes of toxic action (non-polar non-specific toxicants (n=14), polar non-specific toxicants (n=18), uncouplers of oxidative phosphorylation (n=25), inhibitors of photosynthesis (n=15), inhibitors of acetylcholinesterase (n=14), inhibitors of respiration (n=3), thiol-alkylating agents (n=9), reactives (irritants) (n=8), estrogen receptor agonists (n=9)) were tested for cytotoxicity in the neutralred assay, oxygen consumption in isolated mitochondria, oxygen production in algae, inhibition of AChE, reaction with GSH and activity in the yeast estrogen receptor assay. Data on in-vivo aquatic toxicity (LC50, EC50) towards fish, daphnids, algae and bacteria were collected from the literature for reasons of comparison and reference scaling. In the MOA-specific in-vitro test battery, most test chemicals are specifically active at low concentrations, though multiple effects do occur. Graphical and statistical evaluation of the individual classes versus MOA 1 (non-polar non-specific toxicants) identifies interactions related to predominant MOA. Discriminant analyses (DA) on subsets of the data revealed correct classifications between 70% (in-vivo data) and >90% (in

  15. Effects of water quality parameters on boron toxicity to Ceriodaphnia dubia.

    PubMed

    Dethloff, Gail M; Stubblefield, William A; Schlekat, Christian E

    2009-07-01

    The potential modifying effects of certain water quality parameters (e.g., hardness, alkalinity, pH) on the acute toxicity of boron were tested using a freshwater cladoceran, Ceriodaphnia dubia. By comparison, boron acute toxicity was less affected by water quality characteristics than some metals (e.g., copper and silver). Increases in alkalinity over the range tested did not alter toxicity. Increases in water hardness appeared to have an effect with very hard waters (>500 mg/L as CaCO(3)). Decreased pH had a limited influence on boron acute toxicity in laboratory waters. Increasing chloride concentration did not provide a protective effect. Boron acute toxicity was unaffected by sodium concentrations. Median acute lethal concentrations (LC(50)) in natural water samples collected from three field sites were all greater than in reconstituted laboratory waters that matched natural waters in all respects except for dissolved organic carbon. Water effect ratios in these waters ranged from 1.4 to 1.8. In subsequent studies using a commercially available source of natural organic matter, acute toxicity decreased with increased dissolved organic carbon, suggesting, along with the natural water studies, that dissolved organic carbon should be considered further as a modifier of boron toxicity in natural waters where it exceeds 2 mg/L.

  16. Radioactivity level and toxic elemental concentration in groundwater at Dei-Dei and Kubwa areas of Abuja, north-central Nigeria

    NASA Astrophysics Data System (ADS)

    Maxwell, O.; Wagiran, H.; Lee, S. K.; Embong, Z.; Ugwuoke, P. E.

    2015-02-01

    The activity concentrations of uranium and toxic elements in Dei-Dei borehole, Kubwa borehole, Water Board and hand-dug well water samples in Abuja area were measured using inductively coupled plasma mass spectrometry (ICP-MS) system. The results obtained were used to calculate human radiological risk over lifetime consumption by the inhabitants in the area. The activity concentrations of 238U in all the water supplies for drinking ranges from 0.849 mBq L-1 to 2.699 mBq L-1 with the highest value of 2.699 mBq L-1 noted at Dei-Dei borehole whereas the lowest value of 0.849 mBq L-1 was noted in Kubwa borehole. The highest annual effective dose from natural 238U in all the water samples was found in Dei-Dei borehole with a value of 8.9×10-5 mSv y-1 whereas the lowest value was noted in Kubwa borehole with a value of 2.8×10-5 mSv y-1. The radiological risks for cancer mortality were found distinctly low, with the highest value of 1.01×10-7 reported at Dei-Dei borehole compared to Kubwa borehole with a value of 3.01×10-8. The cancer morbidity risk was noted higher in Dei-Dei borehole with a value of 1.55×10-7 whereas lower value of 4.88×10-9 was reported in Kubwa borehole. The chemical toxicity risk of 238U in drinking water over a lifetime consumption has a value of 0.006 μg kg-1 day-1 in Dei-Dei borehole whereas lower value of 0.002 μg kg-1 day-1 was found in Kubwa borehole. Measured lead (Pb) and chromium (Cr) concentrations reported higher in Water Board compared to Dei-Dei and Kubwa borehole samples. Significantly, this study inferred that the 238U concentrations originate from granitic strata of the tectonic events in the area; thus, there was a trend of diffusion towards north to south and re-deposition towards Dei-Dei area.

  17. Accurate prediction of acute fish toxicity of fragrance chemicals with the RTgill-W1 cell assay.

    PubMed

    Natsch, Andreas; Laue, Heike; Haupt, Tina; von Niederhäusern, Valentin; Sanders, Gordon

    2018-03-01

    Testing for acute fish toxicity is an integral part of the environmental safety assessment of chemicals. A true replacement of primary fish tissue was recently proposed using cell viability in a fish gill cell line (RTgill-W1) as a means of predicting acute toxicity, showing good predictivity on 35 chemicals. To promote regulatory acceptance, the predictivity and applicability domain of novel tests need to be carefully evaluated on chemicals with existing high-quality in vivo data. We applied the RTgill-W1 cell assay to 38 fragrance chemicals with a wide range of both physicochemical properties and median lethal concentration (LC50) values and representing a diverse range of chemistries. A strong correlation (R 2  = 0.90-0.94) between the logarithmic in vivo LC50 values, based on fish mortality, and the logarithmic in vitro median effect concentration (EC50) values based on cell viability was observed. A leave-one-out analysis illustrates a median under-/overprediction from in vitro EC50 values to in vivo LC50 values by a factor of 1.5. This assay offers a simple, accurate, and reliable alternative to in vivo acute fish toxicity testing for chemicals, presumably acting mainly by a narcotic mode of action. Furthermore, the present study provides validation of the predictivity of the RTgill-W1 assay on a completely independent set of chemicals that had not been previously tested and indicates that fragrance chemicals are clearly within the applicability domain. Environ Toxicol Chem 2018;37:931-941. © 2017 SETAC. © 2017 SETAC.

  18. Analytical methods for toxic gases from thermal degradation of polymers

    NASA Technical Reports Server (NTRS)

    Hsu, M.-T. S.

    1977-01-01

    Toxic gases evolved from the thermal oxidative degradation of synthetic or natural polymers in small laboratory chambers or in large scale fire tests are measured by several different analytical methods. Gas detector tubes are used for fast on-site detection of suspect toxic gases. The infrared spectroscopic method is an excellent qualitative and quantitative analysis for some toxic gases. Permanent gases such as carbon monoxide, carbon dioxide, methane and ethylene, can be quantitatively determined by gas chromatography. Highly toxic and corrosive gases such as nitrogen oxides, hydrogen cyanide, hydrogen fluoride, hydrogen chloride and sulfur dioxide should be passed into a scrubbing solution for subsequent analysis by either specific ion electrodes or spectrophotometric methods. Low-concentration toxic organic vapors can be concentrated in a cold trap and then analyzed by gas chromatography and mass spectrometry. The limitations of different methods are discussed.

  19. Modelling acceptance of sunlight in high and low photovoltaic concentration

    NASA Astrophysics Data System (ADS)

    Leutz, Ralf

    2014-09-01

    A simple model incorporating linear radiation characteristics, along with the optical trains and geometrical concentration ratios of solar concentrators is presented with performance examples for optical trains of HCPV, LCPV and benchmark flat-plate PV.

  20. Uptake, Accumulation and Toxicity of Silver Nanoparticle in Autotrophic Plants, and Heterotrophic Microbes: A Concentric Review

    PubMed Central

    Tripathi, Durgesh K.; Tripathi, Ashutosh; Shweta; Singh, Swati; Singh, Yashwant; Vishwakarma, Kanchan; Yadav, Gaurav; Sharma, Shivesh; Singh, Vivek K.; Mishra, Rohit K.; Upadhyay, R. G.; Dubey, Nawal K.; Lee, Yonghoon; Chauhan, Devendra K.

    2017-01-01

    Nanotechnology is a cutting-edge field of science with the potential to revolutionize today’s technological advances including industrial applications. It is being utilized for the welfare of mankind; but at the same time, the unprecedented use and uncontrolled release of nanomaterials into the environment poses enormous threat to living organisms. Silver nanoparticles (AgNPs) are used in several industries and its continuous release may hamper many physiological and biochemical processes in the living organisms including autotrophs and heterotrophs. The present review gives a concentric know-how of the effects of AgNPs on the lower and higher autotrophic plants as well as on heterotrophic microbes so as to have better understanding of the differences in effects among these two groups. It also focuses on the mechanism of uptake, translocation, accumulation in the plants and microbes, and resulting toxicity as well as tolerance mechanisms by which these microorganisms are able to survive and reduce the effects of AgNPs. This review differentiates the impact of silver nanoparticles at various levels between autotrophs and heterotrophs and signifies the prevailing tolerance mechanisms. With this background, a comprehensive idea can be made with respect to the influence of AgNPs on lower and higher autotrophic plants together with heterotrophic microbes and new insights can be generated for the researchers to understand the toxicity and tolerance mechanisms of AgNPs in plants and microbes. PMID:28184215

  1. Comparison of the radiological and chemical toxicity of lead

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beitel, G.A.; Mott, S.

    1995-03-01

    This report estimates the worst-case radiological dose to an individual from ingested lead containing picocurie levels of radionuclides and then compares the calculated radiological health effects to the chemical toxic effects from that same lead. This comparison provides an estimate of the consequences of inadvertently recycling, in the commercial market, lead containing nominally undetectable concentrations of radionuclides. Quantitative expressions for the radiological and chemical toxicities of lead are based on concentrations of lead in the blood stream. The result shows that the chemical toxicity of lead is a greater health hazard, by orders of magnitude, than any probable companion radiationmore » dose.« less

  2. Aquatic Toxicity Screening of Fire Fighting Agents

    DTIC Science & Technology

    2005-09-21

    Aqueous Film Forming Foam ( AFFF ), the reference toxicant. The aquatic toxicity...Specification MIL-F-24385F Fire Extinguishing Agent, Aqueous Film Forming Foam ( AFFF ) Liquid Concentrate, For Fresh and Sea Water (MIL SPEC AFFF ). This...extinguish liquid hydrocarbon fuel fires involving aircraft operations. Several types of foam exist including protein, fluoroprotein and aqueous film

  3. Differential concentration-specific effects of caffeine on cell viability, oxidative stress, and cell cycle in pulmonary oxygen toxicity in vitro

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tiwari, Kirti Kumar; Chu, Chun; Couroucli, Xanthi

    Highlights: • Caffeine at 0.05 mM decreases oxidative stress in hyperoxia. • Caffeine at 1 mM decreases cell viability, increases oxidative stress in hyperoxia. • Caffeine at 1 but not 0.05 mM, abrogates hyperoxia-induced G2/M arrest. - Abstract: Caffeine is used to prevent bronchopulmonary dysplasia (BPD) in premature neonates. Hyperoxia contributes to the development of BPD, inhibits cell proliferation and decreases cell survival. The mechanisms responsible for the protective effect of caffeine in pulmonary oxygen toxicity remain largely unknown. A549 and MLE 12 pulmonary epithelial cells were exposed to hyperoxia or maintained in room air, in the presence of differentmore » concentrations (0, 0.05, 0.1 and 1 mM) of caffeine. Caffeine had a differential concentration-specific effect on cell cycle progression, oxidative stress and viability, with 1 mM concentration being deleterious and 0.05 mM being protective. Reactive oxygen species (ROS) generation during hyperoxia was modulated by caffeine in a similar concentration-specific manner. Caffeine at 1 mM, but not at the 0.05 mM concentration decreased the G2 arrest in these cells. Taken together this study shows the novel funding that caffeine has a concentration-specific effect on cell cycle regulation, ROS generation, and cell survival in hyperoxic conditions.« less

  4. Preventing and Managing Toxicities of High-Dose Methotrexate.

    PubMed

    Howard, Scott C; McCormick, John; Pui, Ching-Hon; Buddington, Randall K; Harvey, R Donald

    2016-12-01

    : High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m 2 , is used to treat a range of adult and childhood cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI) in 2%-12% of patients. Nephrotoxicity results from crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. AKI and other toxicities of high-dose methotrexate can lead to significant morbidity, treatment delays, and diminished renal function. Risk factors for methotrexate-associated toxicity include a history of renal dysfunction, volume depletion, acidic urine, and drug interactions. Renal toxicity leads to impaired methotrexate clearance and prolonged exposure to toxic concentrations, which further worsen renal function and exacerbate nonrenal adverse events, including myelosuppression, mucositis, dermatologic toxicity, and hepatotoxicity. Serum creatinine, urine output, and serum methotrexate concentration are monitored to assess renal clearance, with concurrent hydration, urinary alkalinization, and leucovorin rescue to prevent and mitigate AKI and subsequent toxicity. When delayed methotrexate excretion or AKI occurs despite preventive strategies, increased hydration, high-dose leucovorin, and glucarpidase are usually sufficient to allow renal recovery without the need for dialysis. Prompt recognition and effective treatment of AKI and associated toxicities mitigate further toxicity, facilitate renal recovery, and permit patients to receive other chemotherapy or resume HDMTX therapy when additional courses are indicated. High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m 2 , is used for a range of cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI), attributable to crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. When AKI occurs

  5. Preventing and Managing Toxicities of High-Dose Methotrexate

    PubMed Central

    McCormick, John; Pui, Ching-Hon; Buddington, Randall K.; Harvey, R. Donald

    2016-01-01

    High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m2, is used to treat a range of adult and childhood cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI) in 2%–12% of patients. Nephrotoxicity results from crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. AKI and other toxicities of high-dose methotrexate can lead to significant morbidity, treatment delays, and diminished renal function. Risk factors for methotrexate-associated toxicity include a history of renal dysfunction, volume depletion, acidic urine, and drug interactions. Renal toxicity leads to impaired methotrexate clearance and prolonged exposure to toxic concentrations, which further worsen renal function and exacerbate nonrenal adverse events, including myelosuppression, mucositis, dermatologic toxicity, and hepatotoxicity. Serum creatinine, urine output, and serum methotrexate concentration are monitored to assess renal clearance, with concurrent hydration, urinary alkalinization, and leucovorin rescue to prevent and mitigate AKI and subsequent toxicity. When delayed methotrexate excretion or AKI occurs despite preventive strategies, increased hydration, high-dose leucovorin, and glucarpidase are usually sufficient to allow renal recovery without the need for dialysis. Prompt recognition and effective treatment of AKI and associated toxicities mitigate further toxicity, facilitate renal recovery, and permit patients to receive other chemotherapy or resume HDMTX therapy when additional courses are indicated. Implications for Practice: High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m2, is used for a range of cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI), attributable to crystallization of methotrexate in the renal tubular lumen, leading to tubular

  6. 20180311 - Variability of LD50 Values from Rat Oral Acute Toxicity Studies: Implications for Alternative Model Development (SOT)

    EPA Science Inventory

    Alternative models developed for estimating acute systemic toxicity are generally evaluated using in vivo LD50 values. However, in vivo acute systemic toxicity studies can produce variable results, even when conducted according to accepted test guidelines. This variability can ma...

  7. Insecticide treated curtains and residual insecticide treatment to control Aedes aegypti: An acceptability study in Santiago de Cuba

    PubMed Central

    Van der Stuyft, Patrick; Toledo, María Eugenia; Ceballos, Enrique; Fabré, Francisco; Lefèvre, Pierre

    2018-01-01

    Background Within the context of a field trial conducted by the Cuban vector control program (AaCP), we assessed acceptability of insecticide-treated curtains (ITCs) and residual insecticide treatment (RIT) with deltamethrin by the community. We also assessed the potential influence of interviewees’ risk perceptions for getting dengue and disease severity. Methodology/principal findings We embedded a qualitative study using in-depth interviews in a cluster randomized trial (CRT) testing the effectiveness of ITCs and RIT in Santiago de Cuba. In-depth interviews (N = 38) were conducted four and twelve months after deployment of the tools with people who accepted the tools, who stopped using them and who did not accept the tools. Data analysis was deductive. Main reasons for accepting ITCs at the start of the trial were perceived efficacy and not being harmful to health. Constraints linked to manufacturer instructions were the main reason for not using ITCs. People stopped using the ITCs due to perceived allergy, toxicity and low efficacy. Few heads of households refused RIT despite the noting reasons for rejection, such as allergy, health hazard and toxicity. Positive opinions of the vector control program influenced acceptability of both tools. However, frequent insecticide fogging as part of routine AaCP vector control actions diminished perceived efficacy of both tools and, therefore, acceptability. Fifty percent of interviewees did feel at risk for getting dengue and considered dengue a severe disease. However, this did not appear to influence acceptability of ITCs or RIT. Conclusion/significance Acceptability of ITCs and RIT was linked to acceptability of AaCP routine vector control activities. However, uptake and use were not always an indication of acceptability. Factors leading to acceptability may be best identified using qualitative methods, but more research is needed on the concept of acceptability and its measurement. PMID:29293501

  8. Insecticide treated curtains and residual insecticide treatment to control Aedes aegypti: An acceptability study in Santiago de Cuba.

    PubMed

    Pérez, Dennis; Van der Stuyft, Patrick; Toledo, María Eugenia; Ceballos, Enrique; Fabré, Francisco; Lefèvre, Pierre

    2018-01-01

    Within the context of a field trial conducted by the Cuban vector control program (AaCP), we assessed acceptability of insecticide-treated curtains (ITCs) and residual insecticide treatment (RIT) with deltamethrin by the community. We also assessed the potential influence of interviewees' risk perceptions for getting dengue and disease severity. We embedded a qualitative study using in-depth interviews in a cluster randomized trial (CRT) testing the effectiveness of ITCs and RIT in Santiago de Cuba. In-depth interviews (N = 38) were conducted four and twelve months after deployment of the tools with people who accepted the tools, who stopped using them and who did not accept the tools. Data analysis was deductive. Main reasons for accepting ITCs at the start of the trial were perceived efficacy and not being harmful to health. Constraints linked to manufacturer instructions were the main reason for not using ITCs. People stopped using the ITCs due to perceived allergy, toxicity and low efficacy. Few heads of households refused RIT despite the noting reasons for rejection, such as allergy, health hazard and toxicity. Positive opinions of the vector control program influenced acceptability of both tools. However, frequent insecticide fogging as part of routine AaCP vector control actions diminished perceived efficacy of both tools and, therefore, acceptability. Fifty percent of interviewees did feel at risk for getting dengue and considered dengue a severe disease. However, this did not appear to influence acceptability of ITCs or RIT. Acceptability of ITCs and RIT was linked to acceptability of AaCP routine vector control activities. However, uptake and use were not always an indication of acceptability. Factors leading to acceptability may be best identified using qualitative methods, but more research is needed on the concept of acceptability and its measurement.

  9. Retinal Toxicity of Acai Fruit (Euterpe Oleracea) Dye Concentrations in Rabbits: Basic Principles of a New Dye for Chromovitrectomy in Humans.

    PubMed

    Caiado, Rafael R; Peris, Cristiane S; Lima-Filho, Acácio Alves Souza; Urushima, Joao Guilherme Palma; Novais, Eduardo; Badaró, Emmerson; Maia, André; Sinigaglia-Coimbra, Rita; Watanabe, Sung Eun S; Rodrigues, Eduardo B; Farah, Michel Eid; Maia, Mauricio

    2017-08-01

    Evaluate toxicity of acai fruit (Euterpe oleracea) dye concentrations in a rabbit model. Rabbits were injected intravitreously with 10%, 25%, and 35% acai dye concentrations. Control eyes received balanced salt solution (BSS). Electroretinogram (ERG), fundus imaging, fluorescein angiography (FA), optical coherence tomography (OCT), and light and transmission electron microscopy (LM/TEM) were performed. Fundus imaging showed increased vitreous opacity with increased dye concentrations. FA and OCT showed normality with all concentrations. Comparisons between BSS and dye concentrations were analyzed using Kruskal-Wallis and Mood's median test (p < 0.05). At 24 h, ERGs showed reduced amplitudes from baseline in all eyes. Median b-wave amplitudes nonsignificantly decreased and latency increased with 10% and 25%; findings were significant (p < 0.05) for 35%. LM and TEM showed no abnormalities for 10% and 25%. With 35%, TEM showed ganglion cell edema at 24 h that resolved after 7 days. Vacuolization, multilamellar bodies, and nerve bundle damage occurred at 24 h/7 days in the inner nuclear layer. Mitochondrial cristae disruption occurred in the inner photoreceptor segment at 24 h that decreased by 7 days. Ten and twenty-five percent concentrations were safe and may improve identification of the posterior hyaloid and internal limiting membrane during chromovitrectomy in humans.

  10. Toxicity of atmospheric aerosols on marine phytoplankton

    USGS Publications Warehouse

    Paytan, A.; Mackey, K.R.M.; Chen, Y.; Lima, I.D.; Doney, S.C.; Mahowald, N.; Labiosa, R.; Post, A.F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus.We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia.

  11. Pesticide Toxicity Index: a tool for assessing potential toxicity of pesticide mixtures to freshwater aquatic organisms

    USGS Publications Warehouse

    Nowell, Lisa H.; Norman, Julia E.; Moran, Patrick W.; Martin, Jeffrey D.; Stone, Wesley W.

    2014-01-01

    Pesticide mixtures are common in streams with agricultural or urban influence in the watershed. The Pesticide Toxicity Index (PTI) is a screening tool to assess potential aquatic toxicity of complex pesticide mixtures by combining measures of pesticide exposure and acute toxicity in an additive toxic-unit model. The PTI is determined separately for fish, cladocerans, and benthic invertebrates. This study expands the number of pesticides and degradates included in previous editions of the PTI from 124 to 492 pesticides and degradates, and includes two types of PTI for use in different applications, depending on study objectives. The Median-PTI was calculated from median toxicity values for individual pesticides, so is robust to outliers and is appropriate for comparing relative potential toxicity among samples, sites, or pesticides. The Sensitive-PTI uses the 5th percentile of available toxicity values, so is a more sensitive screening-level indicator of potential toxicity. PTI predictions of toxicity in environmental samples were tested using data aggregated from published field studies that measured pesticide concentrations and toxicity to Ceriodaphnia dubia in ambient stream water. C. dubia survival was reduced to ≤ 50% of controls in 44% of samples with Median-PTI values of 0.1–1, and to 0% in 96% of samples with Median-PTI values > 1. The PTI is a relative, but quantitative, indicator of potential toxicity that can be used to evaluate relationships between pesticide exposure and biological condition.

  12. Petroleum hydrocarbon toxicity to corals: A review.

    PubMed

    Turner, Nicholas R; Renegar, D Abigail

    2017-06-30

    The proximity of coral reefs to coastal urban areas and shipping lanes predisposes corals to petroleum pollution from multiple sources. Previous research has evaluated petroleum toxicity to coral using a variety of methodology, including monitoring effects of acute and chronic spills, in situ exposures, and ex situ exposures with both adult and larval stage corals. Variability in toxicant, bioassay conditions, species and other methodological disparities between studies prevents comprehensive conclusions regarding the toxicity of hydrocarbons to corals. Following standardized protocols and quantifying the concentration and composition of toxicant will aid in comparison of results between studies and extrapolation to actual spills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The endocrine disruptor nonylphenol induces sublethal toxicity in vascular plant development at environmental concentrations: A risk for riparian plants and irrigated crops?

    PubMed

    Esteban, S; Llamas, P M; García-Cortés, H; Catalá, M

    2016-09-01

    In recent years, there is a growing concern among the scientific community about the presence of the so-called emergent pollutants in waters of different countries, especially endocrine-disrupting compounds (EDCs) that have the ability to alter the hormonal system. One of the substances found almost ubiquitously and in higher concentrations is the alkylphenol nonylphenol. Albeit this compound is included in priority lists as a probable risk for human health and the environment, little is known about its effects on developing plants. The aim of this work is to assess the acute and sub-chronic toxicity of environmental concentrations of nonylphenol in riparian vascular plant development using spores of the fern Polystichum setiferum and a biomarker-based approach: mitochondrial activity (cell viability), chlorophyll (plant physiology) and DNA content (growth). Mitochondrial activity and DNA content show that nonylphenol induces acute and sub-chronic toxicity at 48 h and after 1 week, respectively. Significant effects are observed in both parameters in fern spores at ng L(-1) but chlorophyll autofluorescence shows little changes. The inhibition of germination by natural allelochemicals has been reported to be related with the active hydroxyl group of phenolic compounds and largely independent of the structural nucleus to which it is attached. Results presented in this study suggest that environmental concentrations of nonylphenol could interfere with higher plant germination development by mimicking natural allelochemicals and/or phytohormones acting as a "phytoendocrine disruptor" likely posing ecophysiological risks. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. In vitro toxicity testing with microplate cell cultures: Impact of cell binding.

    PubMed

    Gülden, Michael; Schreiner, Jeannine; Seibert, Hasso

    2015-06-05

    In vitro generated data on toxic potencies are generally based on nominal concentrations. However, cellular and extracellular binding and elimination processes may reduce the available free fraction of a compound. Then, nominal effective concentrations do not represent appropriate measures of toxic exposure in vitro and underestimate toxic potencies. In this study it was investigated whether cell binding can affect the availability of chemicals in microplate based toxicity assays. To this end the cytotoxicity of compounds like mercury chloride, digitonin and alcohol ethoxylates, accumulated by cells via different modes, was investigated in 96-well microplate cultures with varying concentrations of Balb/c 3T3 cells. The median effective nominal concentrations of all but one of the tested compounds depended linearly from the cell concentration. Applying a previously developed equilibrium distribution model cell concentration-independent median effective extracellular concentrations and cell burdens, respectively, could be calculated. The compounds were accumulated by the cells with bioconcentration factors, BCF, between 480 and ≥ 25,000. Cell binding of the alcohol ethoxylates was correlated with their lipophilicity. The results show that significant cell binding can occur even at the small cell volume fractions (∼ 1 × 10(-5) to 3 × 10(-3) L/L) encountered in microplate assays. To what extent cell binding affects the bioavailability depends on the BCF and the cell volume fraction. EC50 measurements in the presence of at least two different cell concentrations allow for excluding or detecting significant cell binding and for determining more appropriate measures of toxic exposure in vitro like median effective extracellular (free) concentrations or cell burdens. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  15. Optical properties of nonimaging concentrators with corrugated reflectors

    NASA Astrophysics Data System (ADS)

    Roennelid, Mats; Perers, Bengt; Karlsson, Bjorn

    1994-09-01

    A ray tracing study has been performed on the optical properties of cylindrical nonimaging concentrators with linear corrugated reflectors. The corrugations are assumed to be V-formed and to have an extension parallel to the meridian plane of the concentrators. It is shown that the acceptance angle for radiation incident in the meridian plane can be increased for moderate corrugations. This increased acceptance is balanced by a decreased acceptance of radiation from other directions. Calculations of angular acceptance for a 2X compound parabolic concentrator is presented. It is shown that the annual irradiation on a solar collector with booster reflector can be increased if corrugated reflectors are used instead of smooth reflectors.

  16. Optimization of Hyalella azteca IQ Toxicity Test{trademark} for prediction of 28-day sediment toxicity tests

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Novotny, A.N.; Ezzard, C.L.; Douglas, W.S.

    1995-12-31

    The IQ Toxicity Test, which is a rapid screening toxicity test consisting of the observation of in-vivo inhibition of an enzymatic process using a fluorescent substrate, has proven successful for the determination of 24 and 48-hour EC50`s of D. magna, C. dubia, D. pulex and M. bahia. The application of this concept to utilize the freshwater amphipod Hyalella azteca may be an excellent way in which to reduce the standard 28-day chronic sediment toxicity test to possibly one hour`s time. This study incorporates an additive experimental design to explore the effects of and interactions between five specific variables: size ofmore » the amphipod, exposure time to the toxicant, concentration of substrate, exposure time to the substrate, and length of time starved prior to testing. The results of the IQ toxicity test were compared to those of a 28-day chronic sediment toxicity test. Preliminary data indicate that there is an optimal combination of these variables which results in a concise, reproducible toxicity test for use with Hyalella azteca, and would potentially be applicable to other freshwater amphipods in the future.« less

  17. Validating potential toxicity assays to assess petroleum hydrocarbon toxicity in polar soil.

    PubMed

    Harvey, Alexis Nadine; Snape, Ian; Siciliano, Steven Douglas

    2012-02-01

    Potential microbial activities are commonly used to assess soil toxicity of petroleum hydrocarbons (PHC) and are assumed to be a surrogate for microbial activity within the soil ecosystem. However, this assumption needs to be evaluated for frozen soil, in which microbial activity is limited by liquid water (θ(liquid)). Influence of θ(liquid) on in situ toxicity was evaluated and compared to the toxicity endpoints of potential microbial activities using soil from an aged diesel fuel spill at Casey Station, East Antarctica. To determine in situ toxicity, gross mineralization and nitrification rates were determined by the stable isotope dilution technique. Petroleum hydrocarbon-contaminated soil (0-8,000 mg kg(-1)), packed at bulk densities of 1.4, 1.7, and 2.0 g cm(-3) to manipulate liquid water content, was incubated at -5°C for one, two, and three months. Although θ(liquid) did not have a significant effect on gross mineralization or nitrification, gross nitrification was sensitive to PHC contamination, with toxicity decreasing over time. In contrast, gross mineralization was not sensitive to PHC contamination. Toxic response of gross nitrification was comparable to potential nitrification activity (PNA) with similar EC25 (effective concentration causing a 25% effect in the test population) values determined by both measurement endpoints (400 mg kg(-1) for gross nitrification compared to 200 mg kg(-1) for PNA), indicating that potential microbial activity assays are good surrogates for in situ toxicity of PHC contamination in polar regions. Copyright © 2011 SETAC.

  18. Using Delaunay triangulation and Voronoi tessellation to predict the toxicities of binary mixtures containing hormetic compound

    NASA Astrophysics Data System (ADS)

    Qu, Rui; Liu, Shu-Shen; Zheng, Qiao-Feng; Li, Tong

    2017-03-01

    Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of various types of binary mixtures, an interpolation method based on the Delaunay triangulation (DT) and Voronoi tessellation (VT) as well as the training set of direct equipartition ray design (EquRay) mixtures, simply IDVequ. At first, the EquRay was employed to design the basic concentration compositions of five binary mixture rays. The toxic effects of single components and mixture rays at different times and various concentrations were determined by the time-dependent microplate toxicity analysis. Secondly, the concentration-toxicity data of the pure components and various mixture rays were acted as a training set. The DT triangles and VT polygons were constructed by various vertices of concentrations in the training set. The toxicities of unknown mixtures were predicted by the linear interpolation and natural neighbor interpolation of vertices. The IDVequ successfully predicted the toxicities of various types of binary mixtures.

  19. Using Delaunay triangulation and Voronoi tessellation to predict the toxicities of binary mixtures containing hormetic compound

    PubMed Central

    Qu, Rui; Liu, Shu-Shen; Zheng, Qiao-Feng; Li, Tong

    2017-01-01

    Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of various types of binary mixtures, an interpolation method based on the Delaunay triangulation (DT) and Voronoi tessellation (VT) as well as the training set of direct equipartition ray design (EquRay) mixtures, simply IDVequ. At first, the EquRay was employed to design the basic concentration compositions of five binary mixture rays. The toxic effects of single components and mixture rays at different times and various concentrations were determined by the time-dependent microplate toxicity analysis. Secondly, the concentration-toxicity data of the pure components and various mixture rays were acted as a training set. The DT triangles and VT polygons were constructed by various vertices of concentrations in the training set. The toxicities of unknown mixtures were predicted by the linear interpolation and natural neighbor interpolation of vertices. The IDVequ successfully predicted the toxicities of various types of binary mixtures. PMID:28287626

  20. Non-toxic engineered carbon nanodiamond concentrations induce oxidative/nitrosative stress, imbalance of energy metabolism, and mitochondrial dysfunction in microglial and alveolar basal epithelial cells.

    PubMed

    Fresta, Claudia G; Chakraborty, Aishik; Wijesinghe, Manjula B; Amorini, Angela M; Lazzarino, Giacomo; Lazzarino, Giuseppe; Tavazzi, Barbara; Lunte, Susan M; Caraci, Filippo; Dhar, Prajnaparamita; Caruso, Giuseppe

    2018-02-14

    Engineered nanoparticles are finding a wide spectrum of biomedical applications, including drug delivery and capacity to trigger cytotoxic phenomena, potentially useful against tumor cells. The full understanding of their biosafety and interactions with cell processes is mandatory. Using microglial (BV-2) and alveolar basal epithelial (A549) cells, in this study we determined the effects of engineered carbon nanodiamonds (ECNs) on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) production, as well as on energy metabolism. Particularly, we initially measured decrease in cell viability as a function of increasing ECNs doses, finding similar cytotoxic ECN effects in the two cell lines. Subsequently, using apparently non-cytotoxic ECN concentrations (2 µg/mL causing decrease in cell number < 5%) we determined NO and ROS production, and measured the concentrations of compounds related to energy metabolism, mitochondrial functions, oxido-reductive reactions, and antioxidant defences. We found that in both cell lines non-cytotoxic ECN concentrations increased NO and ROS production with sustained oxidative/nitrosative stress, and caused energy metabolism imbalance (decrease in high energy phosphates and nicotinic coenzymes) and mitochondrial malfunctioning (decrease in ATP/ADP ratio).These results underline the importance to deeply investigate the molecular and biochemical changes occurring upon the interaction of ECNs (and nanoparticles in general) with living cells, even at apparently non-toxic concentration. Since the use of ECNs in biomedical field is attracting increasing attention the complete evaluation of their biosafety, toxicity and/or possible side effects both in vitro and in vivo is mandatory before these highly promising tools might find the correct application.

  1. Acute toxicity of fire-retardant and foam-suppressant chemicals to yalella azteca (Saussure)

    USGS Publications Warehouse

    McDonald, Susan F.; Hamilton, Steven J.; Buhl, Kevin J.; Heisinger, James F.

    1997-01-01

    Acute toxicity tests were conducted with Hyalella azteca Saussure (an amphipod) exposed in soft and hard waters to three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F) and two foam suppressants (Phos-Chek WD-881 and Silv-Ex). The chemicals were slightly to moderately toxic to amphipods. The most toxic chemical to amphipods in soft and hard water was Phos-Chek WD-881 (96-h mean lethal concentration [LC50] equal to 10 mg/L and 22 mg/L, respectively), and the least toxic chemical to amphipods in soft water was Fire-Trol GTS-R (96-h LC50 equal to 127 mg/L) and in hard water was Fire-Trol LCG-R (96-h LC50 equal to 535 mg/L). Concentrations of ammonia in tests with the three fire retardants and both water types were greater than reported LC50 values and probably were the major toxic component. Estimated un-ionized ammonia concentrations near the LC50 were frequently less than the reported LC50 ammonia concentrations for amphipods. The three fire retardants were more toxic in soft water than in hard water even though ammonia and un-ionized ammonia concentrations were higher in hard water tests than in soft water tests. The accidental entry of fire-fighting chemicals into aquatic environments could adversely affect aquatic invertebrates, thereby disrupting ecosystem function.

  2. Environmental toxicants and autism spectrum disorders: a systematic review

    PubMed Central

    Rossignol, D A; Genuis, S J; Frye, R E

    2014-01-01

    Although the involvement of genetic abnormalities in autism spectrum disorders (ASD) is well-accepted, recent studies point to an equal contribution by environmental factors, particularly environmental toxicants. However, these toxicant-related studies in ASD have not been systematically reviewed to date. Therefore, we compiled publications investigating potential associations between environmental toxicants and ASD and arranged these publications into the following three categories: (a) studies examining estimated toxicant exposures in the environment during the preconceptional, gestational and early childhood periods; (b) studies investigating biomarkers of toxicants; and (c) studies examining potential genetic susceptibilities to toxicants. A literature search of nine electronic scientific databases through November 2013 was performed. In the first category examining ASD risk and estimated toxicant exposures in the environment, the majority of studies (34/37; 92%) reported an association. Most of these studies were retrospective case–control, ecological or prospective cohort studies, although a few had weaker study designs (for example, case reports or series). Toxicants implicated in ASD included pesticides, phthalates, polychlorinated biphenyls (PCBs), solvents, toxic waste sites, air pollutants and heavy metals, with the strongest evidence found for air pollutants and pesticides. Gestational exposure to methylmercury (through fish exposure, one study) and childhood exposure to pollutants in water supplies (two studies) were not found to be associated with ASD risk. In the second category of studies investigating biomarkers of toxicants and ASD, a large number was dedicated to examining heavy metals. Such studies demonstrated mixed findings, with only 19 of 40 (47%) case–control studies reporting higher concentrations of heavy metals in blood, urine, hair, brain or teeth of children with ASD compared with controls. Other biomarker studies reported that

  3. Effects of organic amendments on the toxicity and bioavailability of cadmium and copper in spiked formulated sediments

    USGS Publications Warehouse

    Besser, J.M.; Brumbaugh, W.G.; May, T.W.; Ingersoll, C.G.

    2003-01-01

    We evaluated the partitioning and toxicity of cadmium (Cd) and copper (Cu) spiked into formulated sediments containing two types of organic matter (OM), i.e., cellulose and humus. Amendments of cellulose up to 12.5% total organic carbon (TOC) did not affect partitioning of Cd or Cu between sediment and pore water and did not significantly affect the toxicity of spiked sediments in acute toxicity tests with the amphipod Hyalella azteca. In contrast, amendments of natural humus shifted the partitioning of both Cd and Cu toward greater concentrations in sediment and lesser concentrations in pore water and significantly reduced toxic effects of both metals. Thresholds for toxicity, based on measured metal concentrations in whole sediment, were greater for both Cd and Cu in sediments amended with a low level of humus (2.9% TOC) than in sediments without added OM. Amendments with a high level of humus (8.9% TOC) eliminated toxicity at the highest spike concentrations of both metals (sediment concentrations of 12.4 ??g Cd/g and 493 ??g Cu/g). Concentrations of Cd in pore water associated with acute toxicity were similar between sediments with and without humus amendments, suggesting that toxicity of Cd was reduced primarily by sorption to sediment OM. However, toxic effects of Cu in humus treatments were associated with greater pore-water concentrations than in controls, suggesting that toxicity of Cu was reduced both by sorption and by complexation with soluble ligands. Both sorption and complexation by OM tend to make proposed sediment quality guidelines (SQGs) based on total metal concentrations more protective for high-OM sediments. Our results suggest that the predictive ability of SQGs could be improved by models of metal interactions with natural OM in sediment and pore water.

  4. Effects of organic amendments on the toxicity and bioavailability of cadmium and copper in spiked formulated sediments.

    PubMed

    Besser, John M; Brumbaugh, William G; May, Thomas W; Ingersoll, Christopher G

    2003-04-01

    We evaluated the partitioning and toxicity of cadmium (Cd) and copper (Cu) spiked into formulated sediments containing two types of organic matter (OM), i.e., cellulose and humus. Amendments of cellulose up to 12.5% total organic carbon (TOC) did not affect partitioning of Cd or Cu between sediment and pore water and did not significantly affect the toxicity of spiked sediments in acute toxicity tests with the amphipod Hyalella azteca. In contrast, amendments of natural humus shifted the partitioning of hoth Cd and Cu toward greater concentrations in sediment and lesser concentrations in pore water and significantly reduced toxic effects of both metals. Thresholds for toxicity, based on measured metal concentrations in whole sediment, were greater for both Cd and Cu in sediments amended with a low level of humus (2.9% TOC) than in sediments without added OM. Amendments with a high level of humus (8.9% TOC) eliminated toxicity at the highest spike concentrations of both metals (sediment concentrations of 12.4 microg Cd/g and 493 microg Cu/g). Concentrations of Cd in pore water associated with acute toxicity were similar between sediments with and without humus amendments, suggesting that toxicity of Cd was reduced primarily by sorption to sediment OM. However, toxic effects of Cu in humus treatments were associated with greater pore-water concentrations than in controls, suggesting that toxicity of Cu was reduced both by sorption and by complexation with soluble ligands. Both sorption and complexation by OM tend to make proposed sediment quality guidelines (SQGs) based on total metal concentrations more protective for high-OM sediments. Our results suggest that the predictive ability of SQGs could be improved by models of metal interactions with natural OM in sediment and pore water.

  5. Toxicity of harmful cyanobacterial blooms to bream and roach.

    PubMed

    Trinchet, Isabelle; Cadel-Six, Sabrina; Djediat, Chakib; Marie, Benjamin; Bernard, Cécile; Puiseux-Dao, Simone; Krys, Sophie; Edery, Marc

    2013-09-01

    Aquatic ecosystems are facing increasing environmental pressures, leading to an increasing frequency of cyanobacterial Harmful Algal Blooms (cHABs) that have emerged as a worldwide concern due to their growing frequency and their potential toxicity to the fauna that threatens the functioning of ecosystems. Cyanobacterial blooms raise concerns due to the fact that several strains produce potent bioactive or toxic secondary metabolites, such as the microcystins (MCs), which are hepatotoxic to vertebrates. These strains of cyanobacteria may be potentially toxic to fish via gastrointestinal ingestion and also by direct absorption of the toxin MC from the water. The purpose of our study was to investigate toxic effects observed in fish taken from several lakes in the Ile-de-France region, where MCs-producing blooms occur. This study comprises histological studies and the measurement of MC concentrations in various organs. The histological findings are similar to those obtained following laboratory exposure of medaka fish to MCs: hepatic lesions predominate and include cell lysis and cell detachment. MC concentrations in the organs revealed that accumulation was particularly high in the digestive tract and the liver, which are known to be classical targets of MCs. In contrast concentrations were very low in the muscles. Differences in the accumulation of MC variants produced by blooms indicate that in order to more precisely evaluate the toxic potential of a specific bloom it is necessary not only to consider the concentration of toxins, but also the variants produced. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Use of blue crab (Callinectes sapidus) embryos for toxicity testing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lee, R.; O`Malley, K.

    1995-12-31

    After fertilization, blue crab embryos develop in egg sacs attached to the female pleopods, often referred to as the sponge. Lipovitellin and lipid droplets in the egg sacs provide energy and nutrition for the developing embryos. Embryos were removed from the sponge and transferred to 24 well culture plates containing sea water with or without toxicants, Each well contained 10 embryos. After 7 to 10 days, embryos hatched to swimming zoea. The effects of toxicants at various concentrations on hatching were determined and the EC{sub 50} calculated. For example, the EC{sub 50} for tributyltin, fenvalerate and mercuric chloride were 50,more » 30 and 90 ng/liter, respectively. The hatching success of control embryos ranged from 95 to 98%. Formation of the heart, eyespot formation, appendage formation and utilization rate of lipovitellin were also effected by exposure to toxicants. At a low concentration of mercuric ion (30ng/liter) the heart formed, but there was no heart beat. Eyespot formation was abnormal in the presence of high concentrations of cadmium (2 {micro}g/liter) and zinc (5 {micro}g/liter), Crab embryos offer many advantages for toxicity testing of pure compounds or mixtures in water, including toxicity testing of sediment pore water. The crab embryos may also serve as models to understand the effect of specific toxicants on the heart and eye spots of crustaceans.« less

  7. Bayesian Multi-Trait Analysis Reveals a Useful Tool to Increase Oil Concentration and to Decrease Toxicity in Jatropha curcas L.

    PubMed Central

    Silva Junqueira, Vinícius; de Azevedo Peixoto, Leonardo; Galvêas Laviola, Bruno; Lopes Bhering, Leonardo; Mendonça, Simone; Agostini Costa, Tania da Silveira; Antoniassi, Rosemar

    2016-01-01

    The biggest challenge for jatropha breeding is to identify superior genotypes that present high seed yield and seed oil content with reduced toxicity levels. Therefore, the objective of this study was to estimate genetic parameters for three important traits (weight of 100 seed, oil seed content, and phorbol ester concentration), and to select superior genotypes to be used as progenitors in jatropha breeding. Additionally, the genotypic values and the genetic parameters estimated under the Bayesian multi-trait approach were used to evaluate different selection indices scenarios of 179 half-sib families. Three different scenarios and economic weights were considered. It was possible to simultaneously reduce toxicity and increase seed oil content and weight of 100 seed by using index selection based on genotypic value estimated by the Bayesian multi-trait approach. Indeed, we identified two families that present these characteristics by evaluating genetic diversity using the Ward clustering method, which suggested nine homogenous clusters. Future researches must integrate the Bayesian multi-trait methods with realized relationship matrix, aiming to build accurate selection indices models. PMID:27281340

  8. An evaluation of the toxicity of contaminated sediments from Waukegan Harbor, Illinois, following remediation

    USGS Publications Warehouse

    Kemble, N.E.; Hardesty, D.G.; Ingersoll, C.G.; Johnson, B. Thomas; Dwyer, F.J.; MacDonald, D.D.

    2000-01-01

    Waukegan Harbor in Illinois was designated as a Great Lakes Area of Concern due to high concentrations of sediment-associated polychlorinated biphenyls (PCBs). The objective of this study was to evaluate the toxicity of 20 sediment samples collected after remediation (primarily dredging) of Waukegan Harbor for PCBs. A 42-day whole sediment toxicity test with the amphipod Hyalella azteca (28-day sediment exposure followed by a 14-day reproductive phase) and sediment toxicity tests with Microtox® were conducted to evaluate sediments from Waukegan Harbor. Endpoints measured were survival, growth, and reproduction (amphipods) and luminescent light emission (bacteria). Survival of amphipods was significantly reduced in 6 of the 20 sediment samples relative to the control. Growth of amphipods (either length or weight) was significantly reduced relative to the control in all samples. However, reproduction of amphipods identified only two samples as toxic relative to the control. The Microtox basic test, conducted with organic extracts of sediments identified only one site as toxic. In contrast, the Microtox solid-phase test identified about 50% of the samples as toxic. A significant negative correlation was observed between reproduction and the concentration of three polynuclear aromatic hydrocarbons (PAHs) normalized to total organic carbon. Sediment chemistry and toxicity data were evaluated using sediment quality guidelines (consensus-based probable effect concentrations, PECs). Results of these analyses indicate that sediment samples from Waukegan Harbor were toxic to H. azteca contaminated at similar contaminant concentrations as sediment samples that were toxic to H. azteca from other areas of the United States. The relationship between PECs and the observed toxicity was not as strong for the Microtox test. The results of this study indicate that the first phase of sediment remediation in Waukegan Harbor successfully lowered concentrations of PCBs at the site

  9. Toxicity of inorganic and organic selenium to Daphnia magna (cladocera) and Chironomus riparius (diptera)

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Dwyer, F.J.; May, T.W.

    1990-01-01

    Elevated concentrations of selenium (Se) have been previously measured in biota sampled from the Kesterson National Wildlife Refuge (KNWR) in the San Joaquin Valley of central California. We conducted acute and chronic toxicity tests with the cladoceran Daphnia magna and the midge Chironomus riparius to determine the toxicity or bioaccumulation of waterborne Se in a reconstituted water similar to the San Joaquin River. Daphnids were more acutely sensitive than midges to the toxic effects of inorganic Se. An organic form of Se (seleno-[L]-methionine) was extremely toxic to daphnids, but was relatively nontoxic to midges. In long-term exposure to a 6:1 mixture of selenate to selenite (a mixture representative of KNWR), the emergence time of adult midges was delayed at Se concentrations ≥ 837 μg/L. Daphnid reproduction and intrinsic rate of natural increase (r) were reduced at Se concentrations ≥ 348 μg/L and growth of adults was reduced at ≥ 156 μg/L. Whole body Mg, K and Na concentrations in daphnids were not affected by chronic Se exposure; however, whole body Ca concentration increased at intermediate Se exposure concentrations. In addition, whole body Cl concentration was reduced at 711 μg Se/L. Daphnids accumulated potentially toxic concentrations of Se from water that may adversely affect fish or waterfowl through the food chain.

  10. Indicate severe toxicity of highway runoff.

    PubMed

    Dorchin, Achik; Shanas, Uri

    2013-09-01

    Road runoff is recognized as a substantial nonpoint source of contamination to the aquatic environment. Highway seasonal first flushes contain particularly high concentrations of pollutants. To fully account for the toxicity potential of the runoff, the cumulative effects of the pollutants should be assessed, ideally by biological analyses. Acute toxicity tests with were used to measure the toxicity of runoff from three major highway sections in Israel for 2 yr. Highway first flushes resulted in the mortality of all tested individuals within 24 to 48 h. A first flush collected from Highway 4 (traffic volume: 81,200 cars d) remained toxic even after dilution to <5% (48 h EC <5%). Synthetic solutions with metal concentrations corresponding to highways' first flushes revealed a synergistic adverse effect on survival and a potential additive effect of nonmetal pollutants in the runoff. Because daphnids and other invertebrates constitute the base of the aquatic food chain, detrimental effects of highway runoff may propagate to higher levels of biological organization. The observed high potential of environmental contamination warrants the control of highway runoff in proximity to natural watercourses. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Effect of heating rate on toxicity of pyrolysis gases from some synthetic polymers

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Soriano, J. A.; Kosola, K. L.

    1977-01-01

    The effect of heating rate on the toxicity of the pyrolysis gases from some synthetic polymers was investigate, using a screening test method. The synthetic polymers were polyethylene, polystyrene, polymethyl methacrylate, polycarbonate, ABS, polyaryl sulfone, polyether sulfone, and polyphenylene sulfide. The toxicants from the sulfur-containing polymers appeared to act more rapidly than the toxicants from the other polymers. It is not known whether this effect is due primarily to differences in concentration or in the nature of the toxicants. The carbon monoxide concentrations found do not account for the observed results.

  12. Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments

    USGS Publications Warehouse

    Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Ivey, Chris D.; Kunz, James L.; Kemble, Nile E.; Schlekat, Christian E.; Garman, Emily R.

    2013-01-01

    This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94–38 µmol/g) and total organic carbon (TOC; 0.42–10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni.

  13. Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments.

    PubMed

    Besser, John M; Brumbaugh, William G; Ingersoll, Christopher G; Ivey, Chris D; Kunz, James L; Kemble, Nile E; Schlekat, Christian E; Garman, Emily Rogevich

    2013-11-01

    This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94-38 µmol/g) and total organic carbon (TOC; 0.42-10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni. © 2013 SETAC.

  14. Toxicity of TiO2 nanoparticles on soil nitrification at environmentally relevant concentrations: Lack of classical dose-response relationships.

    PubMed

    Simonin, Marie; Martins, Jean M F; Le Roux, Xavier; Uzu, Gaëlle; Calas, Aude; Richaume, Agnès

    2017-03-01

    Titanium-dioxide nanoparticles (TiO 2 -NPs) are increasingly released in agricultural soils through, e.g. biosolids, irrigation or nanoagrochemicals. Soils are submitted to a wide range of concentrations of TiO 2 -NPs depending on the type of exposure. However, most studies have assessed the effects of unrealistically high concentrations, and the dose-response relationships are not well characterized for soil microbial communities. Here, using soil microcosms, we assessed the impact of TiO 2 -NPs at concentrations ranging from 0.05 to 500 mg kg -1  dry-soil, on the activity and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB), and nitrite-oxidizing bacteria (Nitrobacter and Nitrospira). In addition, aggregation and oxidative potential of TiO 2 -NPs were measured in the spiking suspensions, as they can be important drivers of TiO 2 -NPs toxicity. After 90 days of exposure, non-classical dose-response relationships were observed for nitrifier abundance or activity, making threshold concentrations impossible to compute. Indeed, AOA abundance was reduced by 40% by TiO 2 -NPs whatever the concentration, while Nitrospira was never affected. Moreover, AOB and Nitrobacter abundances were decreased mainly at intermediate concentrations nitrification was reduced by 25% at the lowest (0.05 mg kg -1 ) and the highest (100 and 500 mg kg -1 ) TiO 2 -NPs concentrations. Path analyses indicated that TiO 2 -NPs affected nitrification through an effect on the specific activity of nitrifiers, in addition to indirect effects on nitrifier abundances. Altogether these results point out the need to include very low concentrations of NPs in soil toxicological studies, and the lack of relevance of classical dose-response tests and ecotoxicological dose metrics (EC50, IC50…) for TiO 2 -NPs impact on soil microorganisms.

  15. Residual toxicity after biodegradation: interactions among benzene, toluene, and chloroform.

    PubMed

    da Silva Nunes-Halldorson, Vânia; Steiner, Robert L; Smith, Geoffrey B

    2004-02-01

    A microbial enrichment originating from a pristine aquifer was found to aerobically biodegrade benzene and toluene, but not chloroform. This enrichment culture was used to study changes in pollutant toxicity as affected by biodegradative activity. Two assays for toxicity were used: (1) a 48-h acute toxicity test using the freshwater invertebrate Ceriodaphnia dubia and (2) microbial biodegradation activity as affected by the presence of mixed pollutants. At 20-ppm concentrations, toluene was significantly more toxic (99% mortality) to C. dubia than benzene (48% mortality) or chloroform (40% mortality). Also at 20-ppm concentrations, but before biodegradation, toluene was significantly more toxic (88% mortality) to C. dubia than benzene (33% mortality). After biodegradation of 98% of toluene and benzene, significant residual toxicity still remained in the bacterial supernatant: toluene-degraded supernatant caused 33% mortality in C. dubia and benzene-degraded supernatant caused 24% mortality. In the second toxicity assay, examining the effect of mixed pollutants on biodegradation activity, the presence of benzene slowed the biodegradation of toluene, but chloroform had no effect on either benzene or toluene biodegradation. Results indicate that significant toxicity remain after biodegradation and that halogenated aliphatic hydrocarbons may have little or no effect on aromatic hydrocarbon biodegradation at sites impacted by mixed pollutants.

  16. Toxic fungi.

    PubMed

    Lampe, K F

    1979-01-01

    Much progress in the areas of identification of active components and elucidation of the toxic mechanisms for the principal poisonous mushrooms has been made in the past decade. This affords a more rational approach to therapeutic management which has consequently resulted in a decrease in the morbidity and mortality associated with these species. However, the effectiveness of a large number of adjuvants for Amanita phalloides poisoning still needs critical laboratory evaluation. The current status of knowledge concerning the toxic potential and contituents of many mushroom species, including the gastroenteric irritants, is inadequate. The problem of geographic variation or genetic strain in the concentration of toxins of many species also requires further investigation. The recent awareness and interest in the pharmacology and toxicology of uncultivated mushrooms in North America and Great Britain should encourage continued active research.

  17. Toxicity of carbon nanotubes: A review.

    PubMed

    Francis, Arul Prakash; Devasena, Thiyagarajan

    2018-03-01

    Carbon nanotubes (CNTs) are widely used in the aerospace, automotive, and electronics industries because of their stability, enhanced metallic, and electrical properties. CNTs are also being investigated for biomedical applications such as drug delivery systems and biosensors. However, the toxic potential of CNTs was reported in various cell lines and animal models. The toxicity depends on diverse properties of the CNTs, such as length, aspect ratio, surface area, degree of aggregation, purity, concentration, and dose. In addition, CNTs and/or associated contaminants were well known for oxidative stress, inflammation, apoptosis, pulmonary inflammation, fibrosis, and granuloma in lungs. The increased production of CNTs likely enhanced the possibility of its exposure in people. Studies on the toxicity of CNTs are mainly focused on the pulmonary effects after intratracheal administration, and only a few studies are reported about the toxicity of CNTs via other routes of exposure. So, it is essential to consider the chronic toxicity of CNTs before using them for various biomedical applications. This review focuses on the potential toxicities of CNTs.

  18. Simultaneous gas-chromatographic determination of toxic gases in combustion atmospheres.

    DOT National Transportation Integrated Search

    1994-09-01

    Measurement of combustion gases produced by burning aircraft cabin materials poses a continuing limitation for smoke toxicity research. Since toxic effects of gases depend on both their concentrations and duration of exposures, frequent atmosphere sa...

  19. Chronic toxicity of a laundry detergent to the freshwater flagellate Euglena gracilis.

    PubMed

    Azizullah, Azizullah; Richter, Peter; Jamil, Muhammad; Häder, Donat-Peter

    2012-10-01

    Chronic toxicity of the common laundry detergent Ariel on the freshwater alga Euglena gracilis was investigated by growing the alga in a medium containing the detergent for 7 days. Cell density, motility, swimming velocity, gravitactic orientation, cell shape, photosynthesis and concentration of light-harvesting pigments were used as end point parameters for the assessment of toxicity. Cell density was significantly reduced at a concentration of 1 mg l(-1) or above. Among the other tested parameters, with the exception of cell shape, gravitaxis and chlorophyll b, all were adversely affected by the detergent at concentrations exceeding 1 mg l(-1). It is concluded that long-term (7-days) exposure to the detergent caused significant toxicity to E. gracilis. Furthermore, long-term tests with E. gracilis can be used as sensitive indicator for the toxicity assessment of laundry detergents in aquatic environments.

  20. Social acceptability of phytoremediation: The role of risk and values.

    PubMed

    Weir, Ellen; Doty, Sharon

    2016-10-02

    A former gas production site that was converted to a public park was chosen as the research location for the present study. Some of the contaminants at the site have been remediated; however, much of the soil is still contaminated with polycyclic aromatic hydrocarbons (PAHs). PAHs are toxic pollutants that have been shown to have numerous negative health effects. The primary form of remediation at the site has been capping, which is usually considered a temporary remediation strategy since it does not remove contaminants from the site but simply covers them, and this requires repeated re-capping efforts. Endophyte-assisted phytoremediation using willow shrubs is an alternative remediation strategy that could improve soil quality and permanently reduce contaminant levels in the soil. The goal of the present study was to explore the social acceptability of utilizing phytoremediation strategies. Surveys were used to explore public perceptions of the park and of using phytoremediation to clean up existing contamination. Results indicated a high level of social acceptability of phytoremediation at the park. Additionally, ecocentrism was shown to be a significant predictor of phytoremediation acceptability. Risk and anthropocentrism were not significant predictors of acceptability. Results suggest that messages intended to encourage the use and acceptability of phytoremediation should focus on the environmental benefits of phytoremediation.

  1. Vanadium bioavailability and toxicity to soil microorganisms and plants.

    PubMed

    Larsson, Maja A; Baken, Stijn; Gustafsson, Jon Petter; Hadialhejazi, Golshid; Smolders, Erik

    2013-10-01

    Vanadium, V, is a redox-sensitive metal that in solution, under aerobic conditions, prevails as the oxyanion vanadate(V). There is little known regarding vanadium toxicity to soil biota, and the present study was set up to determine the toxicity of added vanadate to soil organisms and to investigate the relationship between toxicity and vanadium sorption in soils. Five soils with contrasting properties were spiked with 7 different doses (3.2-3200 mg V kg(-1)) of dissolved vanadate, and toxicity was measured with 2 microbial and 3 plant assays. The median effective concentration (EC50) thresholds of the microbial assays ranged from 28 mg added V kg(-1) to 690 mg added V kg(-1), and the EC50s in the plant assays ranged from 18 mg added V kg(-1) to 510 mg added V kg(-1). The lower thresholds were in the concentration range of the background vanadium in the untreated control soils (15-58 mg V kg(-1)). The vanadium toxicity to plants decreased with a stronger soil vanadium sorption strength. The EC50 values for plants expressed on a soil solution basis ranged from 0.8 mg V L(-1) to 15 mg V L(-1) and were less variable among soils than corresponding values based on total vanadium in soil. It is concluded that sorption decreases the toxicity of added vanadate and that soil solution vanadium is a more robust measure to determine critical vanadium concentrations across soils. © 2013 SETAC.

  2. Contribution of transformation products towards the total herbicide toxicity to tropical marine organisms.

    PubMed

    Mercurio, Philip; Eaglesham, Geoff; Parks, Stephen; Kenway, Matt; Beltran, Victor; Flores, Florita; Mueller, Jochen F; Negri, Andrew P

    2018-03-19

    The toxicity of herbicide degradation (transformation) products is rarely taken into account, even though these are commonly detected in the marine environment, sometimes at concentrations higher than the parent compounds. Here we assessed the potential contribution of toxicity by transformation products of five photosystem II herbicides to coral symbionts (Symbiodinium sp.), the green algae Dunaliella sp., and prawn (Penaeus monodon) larvae. Concentration-dependent inhibition of photosynthetic efficiency (∆F/F m ') was observed for all herbicides in both microalgal species. The toxicity of solutions of aged diuron solutions containing transformation products to Symbiodinium sp. and Dunaliella sp. was greater than could be explained by the concentrations of diuron measured, indicating transformation products contributed to the inhibition of ∆F/F m '. However, the toxicity of aged atrazine, simazine, hexazinone, and ametryn solutions could be explained by the concentration of parent herbicide, indicating no contribution by transformation products. Prawn larval metamorphosis was not sensitive to the herbicides, but preliminary results indicated some toxicity of the transformation products of atrazine and diuron. Risk assessments should take into account the contribution of herbicide transformation products; however, further studies are clearly needed to test the toxicity of a far wider range of transformation products to a representative diversity of relevant taxa.

  3. The SMS3D photovoltaic concentrator

    NASA Astrophysics Data System (ADS)

    Cvetković, Aleksandra; Hernandez, Maikel; Benítez, Pablo; Miñano, Juan Carlos; Schwartz, Joel; Plesniak, Adam; Jones, Russ; Whelan, David

    2008-08-01

    A novel photovoltaic concentrator is presented. The goal is to achieve high concentration design with high efficiency and high acceptance angle that in the same time is compact and convenient for thermal and mechanical management [1]. This photovoltaic system is based on 1 cm2 multi-junction tandem solar cells and an XR concentrator. The XR concentrator in this system is an SMS 3D design formed by one reflective (X) and one refractive (R) free-form surfaces (i.e., without rotational or linear symmetry) and has been chosen for its excellent aspect ratio and for its ability to perform near the thermodynamic limit. It is a mirror-lens device that has no shadowing elements and has square entry aperture (the whole system aperture area is used for collecting light). This large acceptance angle relaxes the manufacturing tolerances of all the optical and mechanical components of the system included the concentrator itself and is one of the keys to get a cost competitive photovoltaic generator. For the geometrical concentration of 1000x the simulation results show the acceptance angle of +/-1.8 deg. The irradiance distribution on the cell is achieved with ultra-short homogenizing prism, whose size is optimised to keep the maximum values under the ones that the cell can accept. The application of the XR optics to high-concentration is being developed in a consortium leaded by The Boeing Company, which has been awarded a project by US DOE in the framework of the Solar America Initiative.

  4. Modelling interactions of toxicants and density dependence in wildlife populations

    USGS Publications Warehouse

    Schipper, Aafke M.; Hendriks, Harrie W.M.; Kauffman, Matthew J.; Hendriks, A. Jan; Huijbregts, Mark A.J.

    2013-01-01

    1. A major challenge in the conservation of threatened and endangered species is to predict population decline and design appropriate recovery measures. However, anthropogenic impacts on wildlife populations are notoriously difficult to predict due to potentially nonlinear responses and interactions with natural ecological processes like density dependence. 2. Here, we incorporated both density dependence and anthropogenic stressors in a stage-based matrix population model and parameterized it for a density-dependent population of peregrine falcons Falco peregrinus exposed to two anthropogenic toxicants [dichlorodiphenyldichloroethylene (DDE) and polybrominated diphenyl ethers (PBDEs)]. Log-logistic exposure–response relationships were used to translate toxicant concentrations in peregrine falcon eggs to effects on fecundity. Density dependence was modelled as the probability of a nonbreeding bird acquiring a breeding territory as a function of the current number of breeders. 3. The equilibrium size of the population, as represented by the number of breeders, responded nonlinearly to increasing toxicant concentrations, showing a gradual decrease followed by a relatively steep decline. Initially, toxicant-induced reductions in population size were mitigated by an alleviation of the density limitation, that is, an increasing probability of territory acquisition. Once population density was no longer limiting, the toxicant impacts were no longer buffered by an increasing proportion of nonbreeders shifting to the breeding stage, resulting in a strong decrease in the equilibrium number of breeders. 4. Median critical exposure concentrations, that is, median toxicant concentrations in eggs corresponding with an equilibrium population size of zero, were 33 and 46 μg g−1 fresh weight for DDE and PBDEs, respectively. 5. Synthesis and applications. Our modelling results showed that particular life stages of a density-limited population may be relatively insensitive to

  5. Toxic epidermal necrolysis: a paradigm of critical illness

    PubMed Central

    Estrella-Alonso, Alfonso; Aramburu, José Antonio; González-Ruiz, Mercedes Yolanda; Cachafeiro, Lucía; Sánchez, Manuel Sánchez; Lorente, José A.

    2017-01-01

    Toxic epidermal necrolysis is an adverse immunological skin reaction secondary in most cases to the administration of a drug. Toxic epidermal necrolysis, Stevens-Johnson syndrome, and multiform exudative erythema are part of the same disease spectrum. The mortality rate from toxic epidermal necrolysis is approximately 30%. The pathophysiology of toxic epidermal necrolysis is similar in many respects to that of superficial skin burns. Mucosal involvement of the ocular and genital epithelium is associated with serious sequelae if the condition is not treated early. It is generally accepted that patients with toxic epidermal necrolysis are better treated in burn units, which are experienced in the management of patients with extensive skin loss. Treatment includes support, elimination, and coverage with biosynthetic derivatives of the skin in affected areas, treatment of mucosal involvement, and specific immunosuppressive treatment. Of the treatments tested, only immunoglobulin G and cyclosporin A are currently used in most centers, even though there is no solid evidence to recommend any specific treatment. The particular aspects of the treatment of this disease include the prevention of sequelae related to the formation of synechiae, eye care to prevent serious sequelae that can lead to blindness, and specific immunosuppressive treatment. Better knowledge of the management principles of toxic epidermal necrolysis will lead to better disease management, higher survival rates, and lower prevalence of sequelae. PMID:29340540

  6. Ethoxylated adjuvants of glyphosate-based herbicides are active principles of human cell toxicity.

    PubMed

    Mesnage, R; Bernay, B; Séralini, G-E

    2013-11-16

    Pesticides are always used in formulations as mixtures of an active principle with adjuvants. Glyphosate, the active ingredient of the major pesticide in the world, is an herbicide supposed to be specific on plant metabolism. Its adjuvants are generally considered as inert diluents. Since side effects for all these compounds have been claimed, we studied potential active principles for toxicity on human cells for 9 glyphosate-based formulations. For this we detailed their compositions and toxicities, and as controls we used a major adjuvant (the polyethoxylated tallowamine POE-15), glyphosate alone, and a total formulation without glyphosate. This was performed after 24h exposures on hepatic (HepG2), embryonic (HEK293) and placental (JEG3) cell lines. We measured mitochondrial activities, membrane degradations, and caspases 3/7 activities. The compositions in adjuvants were analyzed by mass spectrometry. Here we demonstrate that all formulations are more toxic than glyphosate, and we separated experimentally three groups of formulations differentially toxic according to their concentrations in ethoxylated adjuvants. Among them, POE-15 clearly appears to be the most toxic principle against human cells, even if others are not excluded. It begins to be active with negative dose-dependent effects on cellular respiration and membrane integrity between 1 and 3ppm, at environmental/occupational doses. We demonstrate in addition that POE-15 induces necrosis when its first micellization process occurs, by contrast to glyphosate which is known to promote endocrine disrupting effects after entering cells. Altogether, these results challenge the establishment of guidance values such as the acceptable daily intake of glyphosate, when these are mostly based on a long term in vivo test of glyphosate alone. Since pesticides are always used with adjuvants that could change their toxicity, the necessity to assess their whole formulations as mixtures becomes obvious. This challenges

  7. Optical and thermal simulation for wide acceptance angle CPV module

    NASA Astrophysics Data System (ADS)

    Ahmad, Nawwar; Ota, Yasuyuki; Araki, Kenji; Lee, Kan-Hua; Yamaguchi, Masafumi; Nishioka, Kensuke

    2017-09-01

    Concentrator photovoltaic (CPV) technology has the potential to decrease the cost of systems in the near future by using less expensive optical elements in the system which replace the receiving surface aperture and concentrate the sunlight onto small solar cells. One of the main concerns of CPV is the need for high precision tracking system and the relation to the acceptance angle. In this paper, we proposed a CPV module with concentration ratio larger than 100 times and wide acceptance angle. An optical simulation for the module with S-TIM2 glass as a lens material was conducted to estimate the optical performance of the module. Thermal and electrical simulation was also conducted using COMSOL Multiphysics and SPICE respectively to evaluate the working temperature and electrical characteristics of the multijunction solar cell under concentration conditions.

  8. An evaluation of freshwater mussel toxicity data in the derivation of water quality guidance and standards for copper

    USGS Publications Warehouse

    March, F.A.; Dwyer, F.J.; Augspurger, T.; Ingersoll, C.G.; Wang, N.; Mebane, C.A.

    2007-01-01

    The state of Oklahoma has designated several areas as freshwater mussel sanctuaries in an attempt to provide freshwater mussel species a degree of protection and to facilitate their reproduction. We evaluated the protection afforded freshwater mussels by the U.S. Environmental Protection Agency (U.S. EPA) hardness-based 1996 ambient copper water quality criteria, the 2007 U.S. EPA water quality criteria based on the biotic ligand model and the 2005 state of Oklahoma copper water quality standards. Both the criterion maximum concentration and criterion continuous concentration were evaluated. Published acute and chronic copper toxicity data that met American Society for Testing and Materials guidance for test acceptability were obtained for exposures conducted with glochidia or juvenile freshwater mussels. We tabulated toxicity data for glochidia and juveniles to calculate 20 species mean acute values for freshwater mussels. Generally, freshwater mussel species mean acute values were similar to those of the more sensitive species included in the U.S. EPA water quality derivation database. When added to the database of genus mean acute values used in deriving 1996 copper water quality criteria, 14 freshwater mussel genus mean acute values included 10 of the lowest 15 genus mean acute values, with three mussel species having the lowest values. Chronic exposure and sublethal effects freshwater mussel data available for four species and acute to chronic ratios were used to evaluate the criterion continuous concentration. On the basis of the freshwater mussel toxicity data used in this assessment, the hardness-based 1996 U.S. EPA water quality criteria, the 2005 Oklahoma water quality standards, and the 2007 U.S. EPA water quality criteria based on the biotic ligand model might need to be revised to afford protection to freshwater mussels. ?? 2007 SETAC.

  9. Release and toxicity comparison between industrial- and ...

    EPA Pesticide Factsheets

    Many consumer products containing ZnO have raised concern for safety in regards toenvironmental impact and the public health. Widely used sunscreens for protectingagainst UV and avoiding sunburns represent a great exposure to nano-ZnO, one of theingredients commonly applied in sunscreens. Applying nano-products on beaches mayrelease nanoparticles unintentionally into the ocean. Despite the accumulation of suchnano-products in the ocean harming or being detrimental to critical marine organisms,few studies have investigated the release and potential toxicity of nanoparticlesextracted from products and compared them with those from industrial-typenanoparticles. Results show that the cytotoxicity of both industrial- and sunscreenderivednano-ZnO to the marine diatom algae, Thalassiosira pseudonana, increasedas exposure increases over time, as measured by growth inhibition (%) of the algae ata constant concentration of nano-ZnO (10 mg/L). The extent of toxicity appeared to behigher from industrial-type nano-ZnO compared to sunscreen-extracted nano-ZnO,though the extent becomes similar when concentrations increase to 50 mg/L. On theother hand, at a fixed exposure time of 48 hrs, the cytotoxicity increases asconcentrations increase with the higher toxicity shown from the industrial-typecompared to sunscreen-induced nano-ZnO. Results indicate that while industrial-typenano-ZnO shows higher toxicity than sunscreen-derived nano-ZnO, the release andextent of toxicity from n

  10. Validation, acceptance, and extension of a predictive model of reproductive toxicity using ToxCast data

    EPA Science Inventory

    The EPA ToxCast research program uses a high-throughput screening (HTS) approach for predicting the toxicity of large numbers of chemicals. Phase-I tested 309 well-characterized chemicals (mostly pesticides) in over 500 assays of different molecular targets, cellular responses an...

  11. Central Nervous System-Toxic Lidocaine Concentrations Unmask L-Type Ca²⁺ Current-Mediated Action Potentials in Rat Thalamocortical Neurons: An In Vitro Mechanism of Action Study.

    PubMed

    Putrenko, Igor; Ghavanini, Amer A; Meyer Schöniger, Katrin S; Schwarz, Stephan K W

    2016-05-01

    High systemic lidocaine concentrations exert well-known toxic effects on the central nervous system (CNS), including seizures, coma, and death. The underlying mechanisms are still largely obscure, and the actions of lidocaine on supraspinal neurons have received comparatively little study. We recently found that lidocaine at clinically neurotoxic concentrations increases excitability mediated by Na-independent, high-threshold (HT) action potential spikes in rat thalamocortical neurons. Our goal in this study was to characterize these spikes and test the hypothesis that they are generated by HT Ca currents, previously implicated in neurotoxicity. We also sought to identify and isolate the specific underlying subtype of Ca current. We investigated the actions of lidocaine in the CNS-toxic concentration range (100 μM-1 mM) on ventrobasal thalamocortical neurons in rat brain slices in vitro, using whole-cell patch-clamp recordings aided by differential interference contrast infrared videomicroscopy. Drugs were bath applied; action potentials were generated using current clamp protocols, and underlying currents were identified and isolated with ion channel blockers and electrolyte substitution. Lidocaine (100 μM-1 mM) abolished Na-dependent tonic firing in all neurons tested (n = 46). However, in 39 of 46 (85%) neurons, lidocaine unmasked evoked HT action potentials with lower amplitudes and rates of de-/repolarization compared with control. These HT action potentials remained during the application of tetrodotoxin (600 nM), were blocked by Cd (50 μM), and disappeared after superfusion with an extracellular solution deprived of Ca. These features implied that the unmasked potentials were generated by high-voltage-activated Ca channels and not by Na channels. Application of the L-type Ca channel blocker, nifedipine (5 μM), completely blocked the HT potentials, whereas the N-type Ca channel blocker, ω-conotoxin GVIA (1 μM), had little effect. At clinically CNS-toxic

  12. Influence of chloride on the chronic toxicity of sodium nitrate to Ceriodaphnia dubia and Hyalella azteca.

    PubMed

    Soucek, David J; Dickinson, Amy

    2016-09-01

    While it has been well established that increasing chloride concentration in water reduces the toxicity of nitrite to freshwater species, little work has been done to investigate the effect of chloride on nitrate toxicity. We conducted acute and chronic nitrate (as sodium nitrate) toxicity tests with the cladoceran Ceriodaphnia dubia and the amphipod Hyalella azteca (chronic tests only) over a range of chloride concentrations spanning natural chloride levels found in surface waters representative of watersheds of the Great Lakes Region. Chronic nitrate toxicity test results with both crustaceans were variable, with H. azteca appearing to be one of the more sensitive invertebrate species tested and C. dubia being less sensitive. While the variability in results for H. azteca were to an extent related to chloride concentration in test water that was distinctly not the case for C. dubia. We concluded that the chloride dependent toxicity of nitrate is not universal among freshwater crustaceans. An additional sodium chloride chronic toxicity test with the US Lab strain of H. azteca in the present study suggested that when present as predominantly sodium chloride and with relatively low concentrations of other ions, there is a narrow range of chloride concentrations over which this strain is most fit, and within which toxicity test data are reliable.

  13. Oxygen toxicity.

    PubMed

    Stogner, S W; Payne, D K

    1992-12-01

    The objective of this article is to provide an overview of the biochemistry of oxygen metabolism, including the formation of free radicals and the role of endogenous antioxidants. Pathophysiologic correlates underlying the clinical manifestations of oxygen toxicity are reviewed and management strategies are outlined. References from basic science and clinical journals were selected from the authors' files and from a search of a computerized database of the biomedical literature. Articles selected for review included both historical and current literature concerning the biochemistry and pathophysiology of oxygen toxicity in animals and humans. The benefits of oxygen therapy have been known for many years; however, its potential toxicity has not been recognized until the last two decades. The lungs, the eyes, and, under certain conditions, the central nervous system are the organs most affected by prolonged exposure to hyperoxic environments. Free radical formation during cellular metabolism under hyperoxic conditions is recognized as the biochemical basis of oxygen injury to cells and organs. Endogenous antioxidants are a primary means of detoxifying reactive oxygen species and preventing hyperoxia-induced cellular damage. When this defense fails or is overwhelmed by the excessive production of hyperoxia-induced free-radical species, distinctive morphologic changes occur at the cellular level. The amount of hyperoxia required to cause cellular damage and the time course of these changes vary from species to species and from individual to individual within the same species. Age, nutritional status, presence of underlying diseases, and certain drugs may influence the development of oxygen toxicity. There is currently no reliably effective drug for preventing or delaying the development of oxygen toxicity in humans. Use of the lowest effective oxygen concentration, the avoidance of certain drugs, and attention to nutritional and metabolic factors remain the best means

  14. Comparative Toxicity of Preservatives on Immortalized Corneal and Conjunctival Epithelial Cells

    PubMed Central

    Ahdoot, Michael; Marcus, Edward; Asbell, Penny A.

    2009-01-01

    Abstract Purpose Nearly all eye drops contain preservatives to decrease contamination. Nonpreservatives such as disodium-ethylene diamine tetra-acetate (EDTA) and phosphate-buffered saline are also regularly added as buffering agents. These components can add to the toxicity of eye drops and cause ocular surface disease. To evaluate the potential toxicity of these common components and their comparative effects on the ocular surface, a tissue culture model utilizing immortalized corneal and conjunctival epithelial cells was utilized. Methods Immortalized human conjunctival and corneal epithelial cells were grown. At confluency, medium was replaced with 100 μL of varying concentrations of preservatives: benzalkonium chloride (BAK), methyl paraben (MP), sodium perborate (SP), chlorobutanol (Cbl), and stabilized thimerosal (Thi); varying concentrations of buffer: EDTA; media (viable control); and formalin (dead control). After 1 h, solutions were replaced with 150 μL of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazonium bromide). After 4 h, solutions decanted, 100 μL of acid isopropanol added, and the optical density determined at 572 nm to evaluate cell viability. Results Conjunctival and corneal cell toxicity was seen with all preservatives. Depending upon concentration, BAK exhibited from 56% to 89% toxicity. In comparison, Cbl exhibited from 50% to 86%, MP from 30% to 76%, SP from 23% to 59%, and Thi from 70% to 95%. EDTA with minimal toxicity (from 6% to 59%) was indistinguishable from SP. Conclusions Generally, the order of decreasing toxicity at the most commonly used concentrations: Thi (0.0025%) > BAK (0.025%) > Cbl (0.25%) > MP (0.01%) > SP (0.0025%) ≈ EDTA (0.01%). Even at low concentration, these agents will cause some degree of ocular tissue damage. PMID:19284328

  15. Validation of a biotic ligand model on site-specific copper toxicity to Daphnia magna in the Yeongsan River, Korea.

    PubMed

    Park, Jinhee; Ra, Jin-Sung; Rho, Hojung; Cho, Jaeweon; Kim, Sang Don

    2018-03-01

    The objective of this study was to determine whether the water effect ratio (WER) or biotic ligand model (BLM) could be applied to efficiently develop water quality criteria (WQC) in Korea. Samples were collected from 12 specific sites along the Yeongsan River (YSR), Korea, including two sewage treatment plants and one estuary lake. A copper toxicity test using Daphnia magna was performed to determine the WER and to compare to the BLM prediction. The results of the WER from YSR samples also indicated significantly different copper toxicities in all sites. The model-based predictions showed that effluent and estuary waters had significantly different properties in regard to their ability to be used to investigate water characteristics and copper toxicity. It was supposed that the slight water characteristics changes, such as pH, DOC, hardness, conductivity, among others, influence copper toxicity, and these variable effects on copper toxicity interacted with the water composition. The 38% prediction was outside of the validation range by a factor of two in all sites, showing a poor predictive ability, especially in STPs and streams adjacent to the estuary, while the measured toxicity was more stable. The samples that ranged from pH 7.3-7.7 generated stable predictions, while other samples, including those with lower and the higher pH values, led to more unstable predictions. The results also showed that the toxicity of Cu in sample waters to D. magna was closely proportional to the amounts of acidity, including the carboxylic and phenolic groups, as well as the DOC concentrations. Consequently, the acceptable prediction of metal toxicity in various water samples needs the site-specific results considering the water characteristics such as pH and DOC properties particularly in STPs and estuary regions. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Toxicity of Pyrolysis Gases from Elastomers

    NASA Technical Reports Server (NTRS)

    Hilado, Carlos J.; Kosola, Kay L.; Solis, Alida N.; Kourtides, Demetrius A.; Parker, John A.

    1977-01-01

    The toxicity of the pyrolysis gases from six elastomers was investigated. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acryltonitrile rubber exhibited the greatest toxicity under these test conditions; carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

  17. Air toxics concentrations, source identification, and health risks: An air pollution hot spot in southwest Memphis, TN

    NASA Astrophysics Data System (ADS)

    Jia, Chunrong; Foran, Jeffery

    2013-12-01

    Southwest Memphis is a residential region surrounded by fossil fuel burning, steel, refining, and food processing industries, and considerable mobile sources whose emissions may pose adverse health risks to local residents. This study characterizes cancer and non-cancer risks resulting from exposure to ambient air toxics in southwest Memphis. Air toxics samples were collected at a central location every 6 days from June 5, 2008 to January 8, 2010. Volatile organic compounds (VOCs) were collected in evacuated stainless-steel canisters and aldehydes by DNPH cartridges, and samples were analyzed for 73 target compounds. A total of 60 compounds were detected and 39 were found in over 86% of the samples. Mean concentrations of many compounds were higher than those measured in many industrial communities throughout the U.S. The cumulative cancer risk associated with exposure to 13 carcinogens found in southwest Memphis air was 2.3 × 10-4, four times higher than the national average of 5.0 × 10-5. Three risk drivers were identified: benzene, formaldehyde, and acrylonitrile, which contributed 43%, 19%, and 14% to the cumulative risk, respectively. This is the first field study to confirm acrylonitrile as a potential risk driver. Mobile, secondary, industrial, and background sources contributed 57%, 24%, 14%, and 5% of the risk, respectively. The results of this study indicate that southwest Memphis, a region of significant income, racial, and social disparities, is also a region under significant environmental stress compared with surrounding areas and communities.

  18. Dermal and inhalation acute toxic class methods: test procedures and biometric evaluations for the Globally Harmonized Classification System.

    PubMed

    Holzhütter, H G; Genschow, E; Diener, W; Schlede, E

    2003-05-01

    (50) methods. In order to cope with rather narrow dose/concentration classes of the GHS we have, as in our previous publications, combined the outcome of all results that can be obtained during testing for the allocation to one of the defined toxicity classes of the GHS. Our results strongly recommend the deletion of the dermal LD(50) and the inhalation LC(50) test as regulatory tests and the adoption of the dermal and inhalation ATC methods as internationally accepted alternatives.

  19. Pollution Assessment of Toxic and Potentially Toxic Elements in Agricultural Soils of the City Addis Ababa, Ethiopia.

    PubMed

    Aschale, Minbale; Sileshi, Yilma; Kelly-Quinn, Mary; Hailu, Dereje

    2017-02-01

    Due to the significantly fast urban expansion and increased industrial activities, the soils in the farms in Addis Ababa are contaminated by some toxic and potentially toxic elements (As, V, Cr, Fe, Co, Ni, Cu, B, Ba, Sr, Zn, Mn, Pb and Cd) in varying degrees. The mean concentrations of Cr, Ni, As and B in most of the soil farms were found to be higher than the maximum recommended limits. The mean concentrations of Cd, Cu, Pb, Co, Ni and Mn were found to be higher than the background soil concentrations given for uncontaminated soils. Multivariate analyses coupled with correlation analysis were used to identify possible sources. The geo-accumulation index values for Cr, Mn and Pb indicated that the farm soils were unpolluted to moderately polluted as a result of anthropogenic activities. A comprehensive environmental management strategy should be formulated by the government to measure further pollution of the farmland soil.

  20. Constructing, Quantifying, and Validating an Adverse Outcome Pathway for Vascular Developmental Toxicity

    EPA Science Inventory

    Constructing, Quantifying, and Validating an Adverse Outcome Pathway for Vascular Developmental Toxicity The adverse outcome pathway (AOP) for embryonic vascular disruption1 leading to a range of adverse prenatal outcomes was recently entered into the AOP wiki and accepted as par...

  1. Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: documenting the uptake of elemental toxicants.

    PubMed

    Seltzer, Michaeld; Berry, Kristinh

    2005-03-01

    The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

  2. Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: Documenting the uptake of elemental toxicants

    USGS Publications Warehouse

    Seltzer, M.D.; Berry, K.H.

    2005-01-01

    The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

  3. Phytoremediation: A novel strategy for the removal of toxic metals from the environment using plants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Salt, D.E.; Blaylock, M.; Kumar, N. P.B.A.

    1995-05-01

    Toxic metal pollution of waters and soils is a major environmental problem, and most conventional remediation approaches do not provide acceptable solutions. The use of specially selected and engineered metal-accumulating plants for environmental clean-up is an emerging technology called phytoremediation. Three subsets of this technology are applicable to toxic metal remediation: (1) Phytoextraction: the use of metal-accumulating plants to remove toxic metals from soil; (2) Rhizofiltration: the use of plant roots to remove toxic metals from polluted waters; and (3) Phytostabilization: the use of plants to eliminate the bioavailability of toxic metals in soils. Biological mechanisms of toxic metal uptake,more » translocation and resistance as well as strategies for improving phytoremediation are also discussed. 83 refs., 4 figs., 1 tab.« less

  4. Moclobemide poisoning: toxicokinetics and occurrence of serotonin toxicity

    PubMed Central

    Isbister, Geoffrey K; Hackett, L P; Dawson, Andrew H; Whyte, Ian M; Smith, Anthony J

    2003-01-01

    Aims To investigate the spectrum of toxicity of moclobemide overdose, the occurrence of serotonin toxicity, and to estimate toxicokinetic parameters. Methods All moclobemide overdoses presenting over a 10-year period to the Hunter Area Toxicology Service were reviewed. Clinical features, complications, length of stay (LOS) and intensive care (ICU) admission rate were extracted from a standardized, prospectively collected database. Comparisons were made between moclobemide alone and moclobemide with a serotonergic coingestant poisoning. Serotonin toxicity was defined by a combination of Sternbach's criteria and a clinical toxicologist's diagnosis. In five patients serial moclobemide concentrations were measured. Time to maximal plasma concentration (Tmax), peak plasma concentration (Cmax) and terminal elimination half-lives were estimated. Results Of 106 included patients, 33 ingested moclobemide alone, 21 ingested moclobemide with another serotonergic agent (in some cases in therapeutic doses) and 52 ingested moclobemide with a nonserotonergic agent. Eleven (55%) of 21 patients coingesting a serotonergic drug developed serotonin toxicity, which was significantly more than one (3%) of 33 moclobemide-alone overdoses (odds ratio 35, 95% confidence inteval 4, 307; P < 0.0001). In six of these 21 cases severe serotonin toxicity developed with temperature> 38.5 °C and muscle rigidity requiring intubation and paralysis. The 21 patients had a significantly increased LOS (34 h) compared with moclobemide alone overdoses (12 h) (P < 0.0001) and a significantly increased ICU admission rate of 57% vs. 3% (P < 0.0001). Time to peak plasma concentration was delayed in two patients where prepeak samples were obtained. Cmax increased slightly with dose, but all three patients ingesting ≥ 6 g vomited or had charcoal. The mean elimination half-life of moclobemide in the five patients in whom serial moclobemide concentrations were measured was 6.3 h and elimination was first order

  5. Moclobemide poisoning: toxicokinetics and occurrence of serotonin toxicity.

    PubMed

    Isbister, Geoffrey K; Hackett, L P; Dawson, Andrew H; Whyte, Ian M; Smith, Anthony J

    2003-10-01

    To investigate the spectrum of toxicity of moclobemide overdose, the occurrence of serotonin toxicity, and to estimate toxicokinetic parameters. All moclobemide overdoses presenting over a 10-year period to the Hunter Area Toxicology Service were reviewed. Clinical features, complications, length of stay (LOS) and intensive care (ICU) admission rate were extracted from a standardized, prospectively collected database. Comparisons were made between moclobemide alone and moclobemide with a serotonergic coingestant poisoning. Serotonin toxicity was defined by a combination of Sternbach's criteria and a clinical toxicologist's diagnosis. In five patients serial moclobemide concentrations were measured. Time to maximal plasma concentration (Tmax), peak plasma concentration (Cmax) and terminal elimination half-lives were estimated. Of 106 included patients, 33 ingested moclobemide alone, 21 ingested moclobemide with another serotonergic agent (in some cases in therapeutic doses) and 52 ingested moclobemide with a nonserotonergic agent. Eleven (55%) of 21 patients coingesting a serotonergic drug developed serotonin toxicity, which was significantly more than one (3%) of 33 moclobemide-alone overdoses (odds ratio 35, 95% confidence interval 4, 307; P < 0.0001). In six of these 21 cases severe serotonin toxicity developed with temperature >38.5 degrees C and muscle rigidity requiring intubation and paralysis. The 21 patients had a significantly increased LOS (34 h) compared with moclobemide alone overdoses (12 h) (P < 0.0001) and a significantly increased ICU admission rate of 57% vs. 3% (P < 0.0001). Time to peak plasma concentration was delayed in two patients where prepeak samples were obtained. Cmax increased slightly with dose, but all three patients ingesting > or = 6 g vomited or had charcoal. The mean elimination half-life of moclobemide in the five patients in whom serial moclobemide concentrations were measured was 6.3 h and elimination was first order in all

  6. 29 CFR 1915.32 - Toxic cleaning solvents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... space. (2) Either natural ventilation or mechanical exhaust ventilation shall be used to remove the vapor at the source and to dilute the concentration of vapors in the working space to a concentration which is safe for the entire work period. (3) Employees shall be protected against toxic vapors by...

  7. ASSESSING RISKS FROM PHOTOACTIVATED TOXICITY OF PAHS TO AQUATIC ORGANISMS

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are one of the most ubiquitous classes of environmental contaminants. Although most PAHs are toxic only at concentrations large enough to cause narcosis, the toxicity of some can be greatly enhanced through mechanisms that involve molecul...

  8. Developmental toxicity of lead contaminated sediment to mallard ducks

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

    2000-01-01

    Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 I?g/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

  9. Developmental toxicity of lead-contaminated sediment to mallard ducklings

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

    2000-01-01

    Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 ug/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

  10. Mercury toxicity to freshwater organisms: extrapolation using species sensitivity distribution.

    PubMed

    Rodrigues, Andreia C M; Jesus, Fátima T; Fernandes, Marco A F; Morgado, Fernando; Soares, Amadeu M V M; Abreu, Sizenando N

    2013-08-01

    Mercury toxicity to aquatic organisms was evaluated in different taxonomic groups showing the following species sensitivity gradient: Daphnia magna > Daphnia longispina > Pseudokirchneriella subcapitata > Chlorella vulgaris > Lemna minor > Chironomus riparius. Toxicity values ranged from 3.49 μg/L (48 h-EC₅₀ of D. magna) to 1.58 mg/L (48 h-EC₅₀ of C. riparius). A species sensitivity distribution was used to estimate hazardous mercury concentration at 5 % level (HC5) and the predicted no effect concentration (PNEC). The HC5 was 3.18 μg Hg/L and the PNEC varied between 0.636 and 3.18 μg Hg/L, suggesting no risk of acute toxicity to algae, plants, crustaceans and insects in most freshwaters.

  11. Comparative Toxicity of Nanoparticulate CuO and ZnO to Soil Bacterial Communities

    PubMed Central

    Rousk, Johannes; Ackermann, Kathrin; Curling, Simon F.; Jones, Davey L.

    2012-01-01

    The increasing industrial application of metal oxide Engineered Nano-Particles (ENPs) is likely to increase their environmental release to soils. While the potential of metal oxide ENPs as environmental toxicants has been shown, lack of suitable control treatments have compromised the power of many previous assessments. We evaluated the ecotoxicity of ENP (nano) forms of Zn and Cu oxides in two different soils by measuring their ability to inhibit bacterial growth. We could show a direct acute toxicity of nano-CuO acting on soil bacteria while the macroparticulate (bulk) form of CuO was not toxic. In comparison, CuSO4 was more toxic than either oxide form. Unlike Cu, all forms of Zn were toxic to soil bacteria, and the bulk-ZnO was more toxic than the nano-ZnO. The ZnSO4 addition was not consistently more toxic than the oxide forms. Consistently, we found a tight link between the dissolved concentration of metal in solution and the inhibition of bacterial growth. The inconsistent toxicological response between soils could be explained by different resulting concentrations of metals in soil solution. Our findings suggested that the principal mechanism of toxicity was dissolution of metal oxides and sulphates into a metal ion form known to be highly toxic to bacteria, and not a direct effect of nano-sized particles acting on bacteria. We propose that integrated efforts toward directly assessing bioavailable metal concentrations are more valuable than spending resources to reassess ecotoxicology of ENPs separately from general metal toxicity. PMID:22479561

  12. Development of biotic ligand models for chronic manganese toxicity to fish, invertebrates, and algae.

    PubMed

    Peters, Adam; Lofts, Stephen; Merrington, Graham; Brown, Bruce; Stubblefield, William; Harlow, Keven

    2011-11-01

    Ecotoxicity tests were performed with fish, invertebrates, and algae to investigate the effect of water quality parameters on Mn toxicity. Models were developed to describe the effects of Mn as a function of water quality. Calcium (Ca) has a protective effect on Mn toxicity for both fish and invertebrates, and magnesium (Mg) also provides a protective effect for invertebrates. Protons have a protective effect on Mn toxicity to algae. The models derived are consistent with models of the toxicity of other metals to aquatic organisms in that divalent cations can act as competitors to Mn toxicity in fish and invertebrates, and protons act as competitors to Mn toxicity in algae. The selected models are able to predict Mn toxicity to the test organisms to within a factor of 2 in most cases. Under low-pH conditions invertebrates are the most sensitive taxa, and under high-pH conditions algae are most sensitive. The point at which algae become more sensitive than invertebrates depends on the Ca concentration and occurs at higher pH when Ca concentrations are low, because of the sensitivity of invertebrates under these conditions. Dissolved organic carbon concentrations have very little effect on the toxicity of Mn to aquatic organisms. Copyright © 2011 SETAC.

  13. Acute toxicity of fire-control chemicals, nitrogenous chemicals, and surfactants to rainbow trout

    USGS Publications Warehouse

    Buhl, Kevin J.; Hamilton, Steven J.

    2000-01-01

    Laboratory studies were conducted to determine the acute toxicity of three ammonia-based fire retardants (Fire-Trol LCA-F, Fire-Trol LCM-R, and Phos-Chek 259F), five surfactant-based fire-suppressant foams (FireFoam 103B, FireFoam 104, Fire Quench, ForExpan S, and Pyrocap B-136), three nitrogenous chemicals (ammonia, nitrate, and nitrite), and two anionic surfactants (linear alkylbenzene sulfonate [LAS] and sodium dodecyl sulfate [SDS]) to juvenile rainbow trout Oncorhynchus mykiss in soft water. The descending rank order of toxicity (96-h concentration lethal to 50% of test organisms [96-h LC50]) for the fire retardants was as follows: Phos-Chek 259F (168 mg/L) > Fire-Trol LCA-F (942 mg/L) = Fire-Trol LCM-R (1,141 mg/L). The descending rank order of toxicity for the foams was as follows: FireFoam 103B (12.2 mg/L) = FireFoam 104 (13.0 mg/L) > ForExpan S (21.8 mg/L) > Fire Quench (39.0 mg/L) > Pyrocap B-136 [156 mg/L). Except for Pyrocap B-136, the foams were more toxic than the fire retardants. Un-ionized ammonia (NH3; 0.125 mg/L as N) was about six times more toxic than nitrite (0.79 mg/L NO2-N) and about 13,300 times more toxic than nitrate (1,658 mg/L NO3-N). Linear alkylbenzene sulfonate (5.0 mg/L) was about five times more toxic than SDS (24.9 mg/L). Estimated total ammonia and NH3 concentrations at the 96-h LC50s of the fire retardants indicated that ammonia was the primary toxic component in these formulations. Based on estimated anionic surfactant concentrations at the 96-h LC50s of the foams and reference surfactants, LAS was intermediate in toxicity and SDS was less toxic to rainbow trout when compared with the foams. Comparisons of recommended application concentrations to the test results indicate that accidental inputs of these chemicals into streams require substantial dilutions (100-1,750-fold to reach concentrations nonlethal to rainbow trout.

  14. Biomarkers of Exposure to Toxic Substances. Volume 1. Global Experimental Design: Biomarker Discovery for Early Prediction of Organ-Selective Toxicity

    DTIC Science & Technology

    2009-05-30

    in the polyphenols chlorogenic acid , quinic acid and caffeic acid ). It appears in variable concentrations in urine and at much lower concentrations...liver, kidney, toxicity, gene, expression, nephrotoxin, D-serine, hippuric acid , Puromycin, Amphotericin B 16. SECURITY CLASSIFICATION OF: 17...6 1.4.4. Hippuric Acid

  15. Identifying Toxicity Pathways with ToxCast High-Throughput Screening and Applications to Predicting Developmental Toxicity

    EPA Science Inventory

    Results from rodent and non-rodent prenatal developmental toxicity tests for over 300 chemicals have been curated into the relational database ToxRefDB. These same chemicals have been run in concentration-response format through over 500 high-throughput screening assays assessin...

  16. Toxic effect of silver and platinum nanoparticles toward the freshwater microalga Pseudokirchneriella subcapitata.

    PubMed

    Książyk, Małgorzata; Asztemborska, Monika; Stęborowski, Romuald; Bystrzejewska-Piotrowska, Grażyna

    2015-05-01

    The growing use of nanoparticles in a wide range of products has resulted in their release into the aquatic environment; therefore, an understanding of the toxic effects of nanoparticles on aquatic organisms is of permanent importance. The aim of this study was to evaluate the toxicity of silver and platinum nanoparticles toward the freshwater microalga, Pseudokirchneriella subcapitata. Algal growth and photosynthetic pigments were determined to quantitate the effects of varying concentrations of Ag and Pt nanoparticles. The silver nanoparticles were much more toxic than the platinum ones. The concentrations causing total inhibition of algal growth were 5.0 and 22.2 mg L(-1), respectively. Similar results were obtained by analyzing the concentration of photosynthetic pigments in P. subcapitata exposed to nanoparticles. Thus, simple spectrophotometric determination of chlorophyll is a convenient tool for the analysis of nanoparticle toxicity to algae.

  17. Comparative toxicity of two glyphosate-based formulations to Eisenia andrei under laboratory conditions.

    PubMed

    Piola, Lucas; Fuchs, Julio; Oneto, María Luisa; Basack, Silvana; Kesten, Eva; Casabé, Norma

    2013-04-01

    Glyphosate-based products are the leading post-emergent agricultural herbicides in the world, particularly in association with glyphosate tolerant crops. However, studies on the effects of glyphosate-based formulations on terrestrial receptors are scarce. This study was conducted to evaluate the comparative toxicity of two glyphosate-based products: Roundup FG (monoammonium salt, 72% acid equivalent, glyphosate-A) and Mon 8750 (monoammonium salt, 85.4% acid equivalent, glyphosate-B), towards the earthworm Eisenia andrei. Median lethal concentration (LC50) showed that glyphosate-A was 4.5-fold more toxic than glyphosate-B. Sublethal concentrations caused a concentration-dependent weight loss, consistent with the reported effect of glyphosate as uncoupler of oxidative phosphorylation. Glyphosate-A showed deleterious effects on DNA and lysosomal damage at concentrations close to the applied environmental concentrations (14.4 μg ae cm(-2)). With glyphosate-B toxic effects were observed at higher doses, close to its LC50, suggesting that the higher toxicity of formulate A could be attributed to the effects of some of the so-called "inert ingredients", either due to a direct intrinsic toxicity, or to an enhancement in the bioavailability and/or bioaccumulation of the active ingredient. Our results highlight the importance of ecotoxicological assessment not only of the active ingredients, but also of the different formulations usually employed in agricultural practices. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Monitoring late-onset toxicities in phase I trials using predicted risks

    PubMed Central

    Bekele, B. Nebiyou; Ji, Yuan; Shen, Yu; Thall, Peter F.

    2008-01-01

    Late-onset (LO) toxicities are a serious concern in many phase I trials. Since most dose-limiting toxicities occur soon after therapy begins, most dose-finding methods use a binary indicator of toxicity occurring within a short initial time period. If an agent causes LO toxicities, however, an undesirably large number of patients may be treated at toxic doses before any toxicities are observed. A method addressing this problem is the time-to-event continual reassessment method (TITE-CRM, Cheung and Chappell, 2000). We propose a Bayesian dose-finding method similar to the TITE-CRM in which doses are chosen using time-to-toxicity data. The new aspect of our method is a set of rules, based on predictive probabilities, that temporarily suspend accrual if the risk of toxicity at prospective doses for future patients is unacceptably high. If additional follow-up data reduce the predicted risk of toxicity to an acceptable level, then accrual is restarted, and this process may be repeated several times during the trial. A simulation study shows that the proposed method provides a greater degree of safety than the TITE-CRM, while still reliably choosing the preferred dose. This advantage increases with accrual rate, but the price of this additional safety is that the trial takes longer to complete on average. PMID:18084008

  19. Toxicities of triclosan, phenol, and copper sulfate in activated sludge.

    PubMed

    Neumegen, Rosalind A; Fernández-Alba, Amadeo R; Chisti, Yusuf

    2005-04-01

    The effect of toxicants on the BOD degradation rate constant was used to quantitatively establish the toxicity of triclosan, phenol, and copper (II) against activated sludge microorganisms. Toxicities were tested over the following ranges of concentrations: 0-450 mg/L for phenol, 0-2 mg/L for triclosan, and 0-35 mg/L for copper sulfate (pentahydrate). According to the EC(50) values, triclosan was the most toxic compound tested (EC(50) = 1.82 +/- 0.1 mg/L), copper (II) had intermediate toxicity (EC(50) = 18.3 +/- 0.37 mg/L), and phenol was the least toxic (EC(50) = 270 +/- 0.26 mg/L). The presence of 0.2% DMSO had no toxic effect on the activated sludge. The toxicity evaluation method used was simple, reproducible, and directly relevant to activated sludge wastewater treatment processes.

  20. Aerobic biodegradation of a nonylphenol polyethoxylate and toxicity of the biodegradation metabolites.

    PubMed

    Jurado, Encarnación; Fernández-Serrano, Mercedes; Núñez-Olea, Josefa; Lechuga, Manuela

    2009-09-01

    In this paper a study was made of the biodegradation of a non-ionic surfactant, a nonylphenol polyethoxylate, in biodegradability tests by monitoring the residual surfactant matter. The influence of the concentration on the extent of primary biodegradation, the toxicity of biodegradation metabolites, and the kinetics of degradation were also determined. The primary biodegradation was studied at different initial concentrations: 5, 25 and 50 mg/L, (at sub-and supra-critical micelle concentration). The NPEO used in this study can be considered biodegradable since the primary biodegradation had already taken place (a biodegradation greater than 80% was found for the different initial concentration tested). The initial concentration affected the shape of the resulting curve, the mean biodegradation rate and the percentage of biodegradation reached (99% in less than 8 days at 5 mg/L, 98% in less than 13 days at 25 mg/L and 95% in 14 days at 50 mg/L). The kinetic model of Quiroga and Sales (1991) was applied to predict the biodegradation of the NPEO. The toxicity value was measured as EC(20) and EC(50). In addition, during the biodegradation process of the surfactant a toxicity analysis was made of the evolution of metabolites generated, confirming that the subproducts of the biodegradation process were more toxic than the original.

  1. Toxicity of acid mine pit lake water remediated with limestone and phosphorus.

    PubMed

    Neil, Luke L; McCullough, Clint D; Lund, Mark A; Evans, Louis H; Tsvetnenko, Yuri

    2009-11-01

    Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH approximately 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and (c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

  2. Toxicity of acid mine pit lake water remediated with limestone and phosphorus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neil, L.L.; McCullough, C.D.; Lund, M.A.

    2009-11-15

    Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH similar to 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14%more » (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.« less

  3. Parallel Analyses of Alexandrium catenella Cell Concentrations and Shellfish Toxicity in the Puget Sound▿

    PubMed Central

    Dyhrman, Sonya T.; Haley, Sheean T.; Borchert, Jerry A.; Lona, Bob; Kollars, Nicole; Erdner, Deana L.

    2010-01-01

    Alexandrium catenella is widespread in western North America and produces a suite of potent neurotoxins that cause paralytic shellfish poisoning (PSP) in humans and have deleterious impacts on public health and economic resources. There are seasonal PSP-related closures of recreational and commercial shellfisheries in the Puget Sound, but the factors that influence cell distribution, abundance, and relationship to paralytic shellfish toxins (PSTs) in this system are poorly described. Here, a quantitative PCR assay was used to detect A. catenella cells in parallel with state shellfish toxicity testing during the 2006 bloom season at 41 sites from April through October. Over 500,000 A. catenella cells liter−1 were detected at several stations, with two main pulses of cells driving cell distribution, one in June and the other in August. PSTs over the closure limit of 80 μg of PST 100 per g of shellfish tissue were detected at 26 of the 41 sites. Comparison of cell numbers and PST data shows that shellfish toxicity is preceded by an increase in A. catenella cells in 71% of cases. However, cells were also observed in the absence of PSTs in shellfish, highlighting the complex relationship between A. catenella and the resulting shellfish toxicity. These data provide important information on the dynamics of A. catenella cells in the Puget Sound and are a first step toward assessing the utility of plankton monitoring to augment shellfish toxicity testing in this system. PMID:20495054

  4. Comparison of Toxicities to Vibrio fischeri and Fish Based on Discrimination of Excess Toxicity from Baseline Level

    PubMed Central

    Wang, Xiao H.; Yu, Yang; Huang, Tao; Qin, Wei C.; Su, Li M.; Zhao, Yuan H.

    2016-01-01

    Investigations on the relationship of toxicities between species play an important role in the understanding of toxic mechanisms to environmental organisms. In this paper, the toxicity data of 949 chemicals to fish and 1470 chemicals to V. fischeri were used to investigate the modes of action (MOAs) between species. The results show that although there is a positive interspecies correlation, the relationship is poor. Analysis on the excess toxicity calculated from toxic ratios (TR) shows that many chemicals have close toxicities and share the same MOAs between the two species. Linear relationships between the toxicities and octanol/water partition coefficient (log KOW) for baseline and less inert compounds indicate that the internal critical concentrations (CBRs) approach a constant both to fish and V. fischeri for neutral hydrophobic compounds. These compounds share the same toxic mechanisms and bio-uptake processes between species. On the other hand, some hydrophilic compounds exhibit different toxic effects with greatly different log TR values between V. fischeri and fish species. These hydrophilic compounds were identified as reactive MOAs to V. fischeri, but not to fish. The interspecies correlation is improved by adding a hydrophobic descriptor into the correlation equation. This indicates that the differences in the toxic ratios between fish and V. fischeri for these hydrophilic compounds can be partly attributed to the differences of bioconcentration between the two species, rather than the differences of reactivity with the target macromolecules. These hydrophilic compounds may more easily pass through the cell membrane of V. fischeri than the gill and skin of fish, react with the target macromolecules and exhibit excess toxicity. The compounds with log KOW > 7 exhibiting very low toxicity (log TR < –1) to both species indicate that the bioconcentration potential of a chemical plays a very important role in the identification of excess toxicity and MOAs

  5. Toxicity of the pyrolysis products of spacecraft materials

    NASA Technical Reports Server (NTRS)

    Lawrence, W. H.

    1974-01-01

    A number of spacecraft construction materials are evaluated for the toxic effects of their thermodegradation products on rats. Pyrolysis toxicity testing of pyrolysate fumes establish carbon monoxide, carbon dioxide and hydrogen cyanide as the most common intoxicating agents. Generally, COHb levels of animals expiring in the test chamber suggest higher concentrations of CO are produced with larger samples of most materials.

  6. Fish embryo toxicity test: identification of compounds with weak toxicity and analysis of behavioral effects to improve prediction of acute toxicity for neurotoxic compounds.

    PubMed

    Klüver, Nils; König, Maria; Ortmann, Julia; Massei, Riccardo; Paschke, Albrecht; Kühne, Ralph; Scholz, Stefan

    2015-06-02

    The fish embryo toxicity test has been proposed as an alternative for the acute fish toxicity test, but concerns have been raised for its predictivity given that a few compounds have been shown to exhibit a weak acute toxicity in the fish embryo. In order to better define the applicability domain and improve the predictive capacity of the fish embryo test, we performed a systematic analysis of existing fish embryo and acute fish toxicity data. A correlation analysis of a total of 153 compounds identified 28 compounds with a weaker or no toxicity in the fish embryo test. Eleven of these compounds exhibited a neurotoxic mode of action. We selected a subset of eight compounds with weaker or no embryo toxicity (cyanazine, picloram, aldicarb, azinphos-methyl, dieldrin, diquat dibromide, endosulfan, and esfenvalerate) to study toxicokinetics and a neurotoxic mode of action as potential reasons for the deviating fish embryo toxicity. Published fish embryo LC50 values were confirmed by experimental analysis of zebrafish embryo LC50 according to OECD guideline 236. Except for diquat dibromide, internal concentration analysis did not indicate a potential relation of the low sensitivity of fish embryos to a limited uptake of the compounds. Analysis of locomotor activity of diquat dibromide and the neurotoxic compounds in 98 hpf embryos (exposed for 96 h) indicated a specific effect on behavior (embryonic movement) for the neurotoxic compounds. The EC50s of behavior for neurotoxic compounds were close to the acute fish toxicity LC50. Our data provided the first evidence that the applicability domain of the fish embryo test (LC50s determination) may exclude neurotoxic compounds. However, neurotoxic compounds could be identified by changes in embryonic locomotion. Although a quantitative prediction of acute fish toxicity LC50 using behavioral assays in fish embryos may not yet be possible, the identification of neurotoxicity could trigger the conduction of a conventional fish

  7. Wastewater toxicity of tannin- versus chromium-based leather tanneries in Marrakesh, Morocco.

    PubMed

    De Nicola, E; Meriç, S; Della Rocca, C; Gallo, M; Iaccarino, M; Manini, P; Petruzzelli, D; Belgiorno, V; Cheggour, M; Di Gennaro, A; Moukrim, A; Tünay, O; Pagano, G

    2007-10-01

    The toxicity of leather tanning wastewater from a traditional tannery (TT), which is based on vegetable tannin (VT), was compared with wastewater from a tannery combining the use of chromium-based tanning (CT) with VT-based tanning operations. Wastewater samples from a TT and a CT plant as well as from five sewer sampling points were collected in Marrakesh, Morocco, and the concentrations of VT and some selected inorganics were measured. A set of bioassays were used to test wastewater toxicity in sea urchin (Paracentrotus lividus) embryos and sperm, in Daphnia magna, and in marine microalgae (Dunaliella tertiolecta). Toxicity end points included: (1) developmental defects, embryonic mortality, sperm fertilization success, and offspring damage in sea urchins; (2) D. magna immobilization; and (3) algal growth rate inhibition. Toxicity tests on TT and CT effluents (TTE and CTE) were run at dilutions ranging from 0.1% to 2% (sea urchins and algae) or up to 12% in D. magna. Parallel bioassays were run on VT extract (VTE) at nominal tannin concentrations ranging from 0.1 to 10 mg l(-1). The results showed higher toxicity of CTE compared with TTE. CTE toxicity in sea urchins and algae showed concentration-related trends, whereas TTE exerted hormetic effects at levels of 0.1% to 0.2% and toxic effects at levels >or=1%. The same trends were observed for VTE, suggesting a prevailing role of tannin in TTE-associated effects. The moderate wastewater toxicity of VT-based tanneries might prompt interest in the VT tanning process.

  8. Redistribution of boron in leaves reduces boron toxicity.

    PubMed

    Reid, Robert J; Fitzpatrick, Kate L

    2009-11-01

    High soil boron (B) concentrations lead to the accumulation of B in leaves, causing the development of necrotic regions in leaf tips and margins, gradually extending back along the leaf. Plants vary considerably in their tolerance to B toxicity, and it was recently discovered that one of the tolerance mechanisms involved extrusion of B from the root. Expression of a gene encoding a root B efflux transporter was shown to be much higher in tolerant cultivars. In our current research we have shown that the same gene is also upregulated in leaves. However, unlike in the root, the increased activity of the B efflux transporter in the leaves cannot reduce the tissue B concentration. Instead, we have shown that in tolerant cultivars, these transporters redistribute B from the intracellular phase where it is toxic, into the apoplast which is much less sensitive to B. These results provide an explanation of why different cultivars with the same leaf B concentrations can show markedly different toxicity symptoms. We have also shown that rain can remove a large proportion of leaf B, leading to significant improvements of growth of both leaves and roots.

  9. Redistribution of boron in leaves reduces boron toxicity

    PubMed Central

    Fitzpatrick, Kate L

    2009-01-01

    High soil boron (B) concentrations lead to the accumulation of B in leaves, causing the development of necrotic regions in leaf tips and margins, gradually extending back along the leaf. Plants vary considerably in their tolerance to B toxicity, and it was recently discovered that one of the tolerance mechanisms involved extrusion of B from the root. Expression of a gene encoding a root B efflux transporter was shown to be much higher in tolerant cultivars. In our current research we have shown that the same gene is also upregulated in leaves. However, unlike in the root, the increased activity of the B efflux transporter in the leaves cannot reduce the tissue B concentration. Instead, we have shown that in tolerant cultivars, these transporters redistribute B from the intracellular phase where it is toxic, into the apoplast which is much less sensitive to B. These results provide an explanation of why different cultivars with the same leaf B concentrations can show markedly different toxicity symptoms. We have also shown that rain can remove a large proportion of leaf B, leading to significant improvements of growth of both leaves and roots. PMID:20009556

  10. Exposures to multiple air toxics in New York City.

    PubMed Central

    Kinney, Patrick L; Chillrud, Steven N; Ramstrom, Sonja; Ross, James; Spengler, John D

    2002-01-01

    Efforts to assess health risks associated with exposures to multiple urban air toxics have been hampered by the lack of exposure data for people living in urban areas. The TEACH (Toxic Exposure Assessment, a Columbia/Harvard) study was designed to characterize levels of and factors influencing personal exposures to urban air toxics among high school students living in inner-city neighborhoods of New York City and Los Angeles, California. This present article reports methods and data for the New York City phase of TEACH, focusing on the relationships between personal, indoor, and outdoor concentrations in winter and summer among a group of 46 high school students from the A. Philip Randolph Academy, a public high school located in the West Central Harlem section of New York City. Air pollutants monitored included a suite of 17 volatile organic compounds (VOCs) and aldehydes, particulate matter with a mass median aerodynamic diameter concentrations of particle elements were generally similar, suggesting that ambient sources may have driven indoor and personal exposures for most elements. More varied relationships among personal, home indoor, and home outdoor concentrations were observed for VOCs and aldehydes. For formaldehyde and acetaldehyde, and several VOCs, indoor concentrations far exceeded outdoor levels and appeared to dominate personal exposures. Strong seasonal differences in indoor to outdoor concentration ratios were observed for these compounds, reflecting the influence of home air exchange rates. For other VOCs, especially those related to motor vehicle exhaust, more consistent indoor, outdoor, and personal concentrations were observed, suggesting that ambient concentrations may have been the

  11. Exposures to multiple air toxics in New York City.

    PubMed

    Kinney, Patrick L; Chillrud, Steven N; Ramstrom, Sonja; Ross, James; Spengler, John D

    2002-08-01

    Efforts to assess health risks associated with exposures to multiple urban air toxics have been hampered by the lack of exposure data for people living in urban areas. The TEACH (Toxic Exposure Assessment, a Columbia/Harvard) study was designed to characterize levels of and factors influencing personal exposures to urban air toxics among high school students living in inner-city neighborhoods of New York City and Los Angeles, California. This present article reports methods and data for the New York City phase of TEACH, focusing on the relationships between personal, indoor, and outdoor concentrations in winter and summer among a group of 46 high school students from the A. Philip Randolph Academy, a public high school located in the West Central Harlem section of New York City. Air pollutants monitored included a suite of 17 volatile organic compounds (VOCs) and aldehydes, particulate matter with a mass median aerodynamic diameter concentrations of particle elements were generally similar, suggesting that ambient sources may have driven indoor and personal exposures for most elements. More varied relationships among personal, home indoor, and home outdoor concentrations were observed for VOCs and aldehydes. For formaldehyde and acetaldehyde, and several VOCs, indoor concentrations far exceeded outdoor levels and appeared to dominate personal exposures. Strong seasonal differences in indoor to outdoor concentration ratios were observed for these compounds, reflecting the influence of home air exchange rates. For other VOCs, especially those related to motor vehicle exhaust, more consistent indoor, outdoor, and personal concentrations were observed, suggesting that ambient concentrations may have been the

  12. Toxicity of chlorine to zebrafish embryos

    PubMed Central

    Kent, Michael L.; Buchner, Cari; Barton, Carrie; Tanguay, Robert L.

    2014-01-01

    Surface disinfection of fertilized fish eggs is widely used in aquaculture to reduce extraovum pathogens that may be released from brood fish during spawning, and this is routinely used in zebrafish (Danio rerio) research laboratories. Most laboratories use approximately 25 – 50 ppm unbuffered chlorine solution for 5 – 10 min. Treatment of embryos with chlorine has significant germicidal effects for many Gram-negative bacteria, viruses, and trophozoite stages of protozoa, it has reduced efficacy against cyst or spore stages of protozoa and certain Mycobacterium spp. Therefore, we evaluated the toxicity of unbufferred and buffered chlorine solution to embryos exposed at 6 or 24 hours post-fertilization (hpf) to determine if higher concentrations can be used for treating zebrafish embryos. Most of our experiments entailed using an outbred line (5D), with both mortality and malformations as endpoints. We found that 6 hpf embryos consistently were more resistant than 24 hpf embryos to the toxic effects of chlorine. Chlorine is more toxic and germicidal at lower pHs, and chlorine causes elevated pH. Consistent with this, we found that unbufferred chlorine solutions (pH ca 8–9) were less toxic at corresponding concentrations than solutions buffered to pH 7. Based on our findings here, we recommend treating 6 hpf embryos for 10 min and 24 hpf for 5 min with unbuffered chlorine solution at 100 ppm. One trial indicated that AB fish, a popular outbred line, are more susceptible to toxicity than 5Ds. This suggests that variability between zebrafish lines occurs, and researchers should evaluate each line or strain under their particular laboratory conditions for selection of the optimum chlorine treatment procedure. PMID:24429474

  13. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

    NASA Astrophysics Data System (ADS)

    Kvitek, L.; Panacek, A.; Prucek, R.; Soukupova, J.; Vanickova, M.; Kolar, M.; Zboril, R.

    2011-07-01

    The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

  14. Behavioral indicators of sublethal toxicity in rainbow trout

    USGS Publications Warehouse

    Little, Edward E.; Archeski, Richard D.; Flerov, Boris A.; Kozlovskaya, Vera I.

    1990-01-01

    Four measures of behavior-spontaneous swimming activity, swimming capacity, feeding behavior, and vulnerability to predation-were assessed as indicators of sublethal toxicity in rainbow trout (Oncorhynchus mykiss) in 96-hr exposures to sublethal concentrations of six agricultural chemicals: carbaryl, chlordane, dimethylamine salt of 2,4-dichlorophenoxyacetic acid (2,4-DMA), tributyl phosphorotrithioate (DBF 1), methyl parathion, and pentachlorophenol. After exposures, behavioral changes consistently demonstrated sublethal toxicity, but effects on specific behaviors varied with contaminants and their concentrations were altered by the water quality criterion concentration for chlordane (2 μg/L), and at a concentration of DEF (5 μg/L) that had previously been shown to inhibit growth and survival after a 90-day exposure. Feeding behavior was inhibited most by exposure to DEF, 2,4-DMA, and methyl parathion. Vulnerability to predation was heightened most by exposure to carbaryl and pentachlorophenol. Although all chemicals inhibited spontaneous swimming activity, only carbaryl, DEF, and 2,4-DMA influenced swimming capacity.

  15. Assessment of surface concentrations in resorbable ocular implants: controlled drug delivery devices for 5-fluorouracil (5-FU)

    NASA Astrophysics Data System (ADS)

    Milne, Peter J.; Gautier, Sandrine; Parel, Jean-Marie A.; Jallet, Valerie

    1997-05-01

    The antineoplastic drug 5-fluorouracil (5-fluoro- 2,4,(1H,3H)-pyrimidinedione; 5-FU) has been used to control proliferation of penetrating fibroblasts and to prevent channel closure following glaucoma filtration surgery (trabeculectomy) or laser sclerectomy. Because of the toxicity of the drug, administration of low dosages slowly over time, at the site of the desired treatment, is indicated for optimum efficacy. Repeated injections of low dosages of the drug represent an undesirable intervention and may also result in unwanted toxicity to the corneal epithelium. A suitable biocompatible and resorbable polymer matrix composed of a poly (D,L-lactic-co-glycolic acid: PLGA) has been admixed with varying amounts of 5-FU and cast as shapes suitable for intracorneal implantation. Slow biodegradation of this polymer over a one to two week period has been shown to result in an acceptably slow drug release mechanism. An issue arising during the clinical evaluation of the efficacy of this drug delivery system was how best to quantify the concentration of 5-FU and its distribution spatially in the solid implant. FT-IR and FT-Raman spectroscopies distinguishes between the drug and the polymer matrix and were used to differentiate and quantitate the 5-FU concentration of the implants.

  16. Acute toxicity to goldfish of mixtures of chloramines, copper, and linear alkylate sulfonate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tsai, C.F.; McKee, J.A.

    1980-01-01

    The toxicity to goldfish (Carassius auratus) of mixtures of chloramines, copper, and linear alkylate sulfonate (LAS) was studied by continuous-flow toxicity tests during an exposure period of 96 hours. The individual toxicities of these three chemicals are either additive or synergistic in mixtures, depending on the rate of toxic action of the individual chemical, the toxicity ratio of the chemicals in the mixtures, and the concentration of the mixtures.

  17. Experimental characterization of Fresnel-Köhler concentrators

    NASA Astrophysics Data System (ADS)

    Zamora, Pablo; Benítez, Pablo; Mohedano, Rubén; Cvetković, Aleksandra; Vilaplana, Juan; Li, Yang; Hernández, Maikel; Chaves, Julio; Miñano, Juan C.

    2012-01-01

    Most cost-effective concentrated photovoltaics (CPV) systems are based on an optical train comprising two stages, the first being a Fresnel lens. Among them, the Fresnel-Köhler (FK) concentrator stands out owing to both performance and practical reasons. We describe the experimental measurements procedure for FK concentrator modules. This procedure includes three main types of measurements: electrical efficiency, acceptance angle, and irradiance uniformity at the solar cell plane. We have collected here the performance features of two different FK prototypes (ranging different f-numbers, concentration ratios, and cell sizes). The electrical efficiencies measured in both prototypes are high and fit well with the models, achieving values up to 32.7% (temperature corrected, and with no antireflective coating on SOE or POE surfaces) in the best case. The measured angular transmission curves show large acceptance angles, again perfectly matching the expected values [measured concentration acceptance product (CAP) values over 0.56]. The irradiance pattern on the cell (obtained with a digital camera) shows an almost perfectly uniform distribution, as predicted by raytrace simulations. All these excellent on-sun results confirm the FK concentrator as a potentially cost-effective solution for the CPV market.

  18. Toxicity of manganese to Ceriodaphnia dubia and Hyalella azteca

    USGS Publications Warehouse

    Lasier, P.J.; Winger, P.V.; Bogenrieder, K.J.

    2000-01-01

    Manganese is a toxic element frequently overlooked when assessing toxicity of effluents, sediments and pore waters. Manganese can be present at toxic levels in anoxic solutions due to its increased solubility under chemically-reducing conditions, and it can remain at those levels for days in aerated test waters due to slow precipitation kinetics. Ceriodaphnia dubia and Hyalella azteca are freshwater organisms often used for toxicity testing and recommended for assessments of effluents and pore waters. Lethal and reproductive-inhibition concentrations of Mn were determined for C. dubia in acute 48h tests and chronic 3-brood tests using animals <24 h old and between 24 and 48 h old. Sensitivity of H. azteca was determined with 7d old animals in acute 96h tests. Tests were run at three levels of water hardness to assess the amelioratory effect, which was often significant. Manganese concentrations were measured analytically at test initiation and after 96 h for calculations of toxicity endpoints and determinations of Mn precipitation during the tests. Minimal amounts of Mn (below 3%) precipitated within 96 h. LC50s determined for H. azteca progressively increased from 3.0 to 8.6 to 13.7 mg Mn/L in soft, moderately-hard and hard waters, respectively. The tolerance of C. dubia to Mn was not significantly different between moderately-hard and hard waters, but was significantly lower in soft water. There was no significant difference in Mn sensitivity between the ages of C. dubia tested. Acute LC50 values for C. dubia averaged 6.2, 14.5 and 15.2 mg Mn/L and chronic IC50 values averaged 3.9, 8.5 and 11.5 mg Mn/L for soft, moderately-hard and hard waters, respectively. Manganese toxicity should be considered when assessing solutions with concentrations near these levels.

  19. Leaching and toxicity behavior of coal-biomass waste cocombustion ashes.

    PubMed

    Skodras, G; Prokopidou, M; Sakellaropoulos, G P

    2006-08-01

    Land disposal of ash residues, obtained from the cocombustion of Greek lignite with biomass wastes, is known to create problems due to the harmful constituents present. In this regard, the leachability of trace elements from lignite, biomass, and blends cocombustion ashes was investigated by using the Toxicity Characteristic Leaching Procedure (TCLP) of the US Environmental Protection Agency (US EPA). In this work, the toxicity of the aqueous leachates and the concentrations of the metals obtained from the leaching procedure were measured using the Microtox test (Vibrio fischeri) and inductive coupled plasma-atomic emission spectrometer (ICP-AES), respectively. The toxic effects of most leachates on Vibrio fischeri were found to be significantly low in both 45% and 82% screening test protocols. However, the liquid sample originating from olive kernels fly ash (FA4) caused the highest toxic effect in both protocols, which can be attributed to its relatively high concentrations of As, Cd, Co, Cu, Mn, Ni, and Zn. Copyright 2006 Wiley Periodicals, Inc.

  20. Transport of pyruvate into mitochondria is involved in methylmercury toxicity

    PubMed Central

    Lee, Jin-Yong; Ishida, Yosuke; Takahashi, Tsutomu; Naganuma, Akira; Hwang, Gi-Wook

    2016-01-01

    We have previously demonstrated that the overexpression of enzymes involved in the production of pyruvate, enolase 2 (Eno2) and D-lactate dehydrogenase (Dld3) renders yeast highly sensitive to methylmercury and that the promotion of intracellular pyruvate synthesis may be involved in intensifying the toxicity of methylmercury. In the present study, we showed that the addition of pyruvate to culture media in non-toxic concentrations significantly enhanced the sensitivity of yeast and human neuroblastoma cells to methylmercury. The results also suggested that methylmercury promoted the transport of pyruvate into mitochondria and that the increased pyruvate concentrations in mitochondria were involved in intensifying the toxicity of methylmercury without pyruvate being converted to acetyl-CoA. Furthermore, in human neuroblastoma cells, methylmercury treatment alone decreased the mitochondrial membrane potential, and the addition of pyruvate led to a further significant decrease. In addition, treatment with N-acetylcysteine (an antioxidant) significantly alleviated the toxicity of methylmercury and significantly inhibited the intensification of methylmercury toxicity by pyruvate. Based on these data, we hypothesize that methylmercury exerts its toxicity by raising the level of pyruvate in mitochondria and that mitochondrial dysfunction and increased levels of reactive oxygen species are involved in the action of pyruvate. PMID:26899208

  1. Prediction of acute inhalation toxicity using in vitro lung surfactant inhibition.

    PubMed

    Sørli, Jorid B; Huang, Yishi; Da Silva, Emilie; Hansen, Jitka S; Zuo, Yi Y; Frederiksen, Marie; Nørgaard, Asger W; Ebbehøj, Niels E; Larsen, Søren T; Hougaard, Karin S

    2018-01-01

    Private consumers and professionals may experience acute inhalation toxicity after inhaling aerosolized impregnation products. The distinction between toxic and non-toxic products is difficult to make for producers and product users alike, as there is no clearly described relationship between the chemical composition of the products and induction of toxicity. The currently accepted method for determination of acute inhalation toxicity is based on experiments on animals; it is time-consuming, expensive and causes stress for the animals. Impregnation products are present on the market in large numbers and amounts and exhibit great variety. Therefore, an alternative method to screen for acute inhalation toxicity is needed. The aim of our study was to determine if inhibition of lung surfactant by impregnation products in vitro could accurately predict toxicity in vivo in mice. We tested 21 impregnation products using the constant flow through set-up of the constrained drop surfactometer to determine if the products inhibited surfactant function or not. The same products were tested in a mouse inhalation bioassay to determine their toxicity in vivo. The sensitivity was 100%, i.e., the in vitro method predicted all the products that were toxic for mice to inhale. The specificity of the in vitro test was 63%, i.e., the in vitro method found three false positives in the 21 tested products. Six of the products had been involved in accidental human inhalation where they caused acute inhalation toxicity. All of these six products inhibited lung surfactant function in vitro and were toxic to mice.

  2. Risk Assessment for Criteria Pollutants and Air Toxics in two Sites of Mexico City During 2003 Field Campaign

    NASA Astrophysics Data System (ADS)

    García, A. R.; Grutter, M. M.; Volkamer, R. M.

    2007-05-01

    An environmental risk assessment for criteria pollutants and air toxics in Mexico City is presented. The data used in the study were collected by FTIR and DOAS systems during the Mexico City Metropolitan Area field campaign on April 2003 (MCMA2003). The systems were deployed in two different sites: One in downtown (Merced) and the other in the south east (CENICA). Concentrations of criteria pollutants and air toxics were obtained every 5 min and were used to obtain hourly average concentrations and the month average for April. The concentration values were used to estimate the risks of acute and chronic exposure to ambient concentrations using risk measures like hazard index, life cancer probability, life lost expectancy and maximum individual cancer risk. Results revealed that both sites have similar risk values. For acute exposure, criteria pollutants have larger risks than air toxics, but air toxics have larger risks for chronic exposure. Ambient concentrations of benzene showed the largest carcinogenic risk of the measured air toxics.

  3. Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

    PubMed Central

    Sauerheber, Richard

    2013-01-01

    The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings. PMID:23840230

  4. Physiologic conditions affect toxicity of ingested industrial fluoride.

    PubMed

    Sauerheber, Richard

    2013-01-01

    The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

  5. Toxicity characterization of urban stormwater with bioanalytical tools.

    PubMed

    Tang, Janet Y M; Aryal, Rupak; Deletic, Ana; Gernjak, Wolfgang; Glenn, Eva; McCarthy, David; Escher, Beate I

    2013-10-01

    Stormwater harvesting has become an attractive alternative strategy to address the rising demand for urban water supply due to limited water sources and population growth. Nevertheless, urban stormwater is also a major source of surface water pollution. Runoff from different urban catchments with source contributions from anthropogenic activities and various land uses causes variable contaminant profiles, thus posing a challenging task for environmental monitoring and risk assessment. A thorough understanding of raw stormwater quality is essential to develop appropriate treatment facilities for potential indirect potable reuse of stormwater. While some of the key chemical components have previously been characterized, only scarce data are available on stormwater toxicity. We benchmarked stormwater samples from urban, residential and industrial sites across various Australian capital cities against samples from the entire water cycle, from sewage to drinking water. Six biological endpoints, targeting groups of chemicals with modes of toxic action of particular relevance for human and environmental health, were investigated: non-specific toxicity (Microtox and combined algae test), the specific modes of action of phytotoxicity (combined algae test), dioxin-like activity (AhR-CAFLUX), and estrogenicity (E-SCREEN), as well as reactive toxicity encompassing genotoxicity (umuC) and oxidative stress (AREc32). Non-specific toxicity was highly variable across sites. The baseline toxicity equivalent concentrations of the most polluted samples were similar to secondary treated effluent from wastewater treatment plants. Phytotoxicity results correlated well with the measured herbicide concentrations at all sites. High estrogenicity was found in two sampling events and could be related to sewage overflow. Genotoxicity, dioxin-like activity, and oxidative stress response were evident in only three of the samples where the stormwater drain was beside a heavy traffic road

  6. Toxic effects of selenium and copper on the planarian, Dugesia dorotocephala

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rauscher, J.D.

    1988-01-01

    Aquatic toxicologists have become increasingly concerned with the effects of sublethal concentrations of toxicants on aquatic organisms. Sublethal effects of toxicants on freshwater invertebrates were reviewed. Selenium (Se) and copper (Cu) are both essential trace elements and toxicants. Se has been reported to alter the toxicity of heavy metals. Planarians, Dugesia dorotocephala, were used as test animals. The objectives of this study were to determine: (1) acute toxicity of Se on planarians and the effect of the number of planarians per test chamber, (2) interaction of the acute toxicity of Se and Cu on planarians, and (3) sublethal effects ofmore » Se and Cu on planarians.« less

  7. Blacks and the Toxics Crisis.

    ERIC Educational Resources Information Center

    Johnson, James H., Jr.; Oliver, Melvin L.

    1989-01-01

    Employs the case study approach to show how the Reagan Administration's assault on environmental policies more adversely affects blacks and other minority groups than whites. Reviews recent research that shows minorities heavily concentrated in dangerous occupations and communities where the risk of exposure to toxic pollutants is greatest. (JS)

  8. ACCEPT 2: A public library of cluster properties

    NASA Astrophysics Data System (ADS)

    Donahue, Megan

    2012-09-01

    The current public ACCEPT database of cluster properties includes radial profiles of Tx, n_elec, entropy, and cooling time. We propose to more than double the current number of clusters in ACCEPT and to expand the current suite of properties to include uniformly measured profiles of gas mass and hydrostatic equilibrium mass along with signatures of dynamical relaxation (centroid shift, power ratios, surface brightness concentration, temperature ratios) and global quantities such as core-excised Tx, Lx, and metallicities. We will explore the relationship between cool cores and dynamical relaxation, the reliability of hydrostatic mass profiles, and the dependence of the gas mass fraction on halo mass, redshift, and the degree of relaxation. ACCEPT2 will enable further community science.

  9. Validation of alternative methods for toxicity testing.

    PubMed Central

    Bruner, L H; Carr, G J; Curren, R D; Chamberlain, M

    1998-01-01

    Before nonanimal toxicity tests may be officially accepted by regulatory agencies, it is generally agreed that the validity of the new methods must be demonstrated in an independent, scientifically sound validation program. Validation has been defined as the demonstration of the reliability and relevance of a test method for a particular purpose. This paper provides a brief review of the development of the theoretical aspects of the validation process and updates current thinking about objectively testing the performance of an alternative method in a validation study. Validation of alternative methods for eye irritation testing is a specific example illustrating important concepts. Although discussion focuses on the validation of alternative methods intended to replace current in vivo toxicity tests, the procedures can be used to assess the performance of alternative methods intended for other uses. Images Figure 1 PMID:9599695

  10. Influence of flow-through and renewal exposures on the toxicity of copper to rainbow trout

    USGS Publications Warehouse

    Welsh, P.G.; Lipton, J.; Mebane, C.A.; Marr, J.C.A.

    2008-01-01

    We examined changes in water chemistry and copper (Cu) toxicity in three paired renewal and flow-through acute bioassays with rainbow trout (Oncorhynchus mykiss). Test exposure methodology influenced both exposure water chemistry and measured Cu toxicity. Ammonia and organic carbon concentrations were higher and the fraction of dissolved Cu lower in renewal tests than in paired flow-through tests. Cu toxicity was also lower in renewal tests; 96 h dissolved Cu LC50 values were 7-60% higher than LC50s from matching flow-through tests. LC50 values in both types of tests were related to dissolved organic carbon (DOC) concentrations in exposure tanks. Increases in organic carbon concentrations in renewal tests were associated with reduced Cu toxicity, likely as a result of the lower bioavailability of Cu-organic carbon complexes. The biotic ligand model of acute Cu toxicity tended to underpredict toxicity in the presence of DOC. Model fits between predicted and observed toxicity were improved by assuming that only 50% of the measured DOC was reactive, and that this reactive fraction was present as fulvic acid. ?? 2007 Elsevier Inc. All rights reserved.

  11. Ecotoxicogenomic assessment of diclofenac toxicity in soil.

    PubMed

    Chen, Guangquan; den Braver, Michiel W; van Gestel, Cornelis A M; van Straalen, Nico M; Roelofs, Dick

    2015-04-01

    Diclofenac is widely used as nonsteroidal anti-inflammatory drug leaving residues in the environment. To investigate effects on terrestrial ecosystems, we measured dissipation rate in soil and investigated ecotoxicological and transcriptome-wide responses in Folsomia candida. Exposure for 4 weeks to diclofenac reduced both survival and reproduction of F. candida in a dose-dependent manner. At concentrations ≥ 200 mg/kg soil diclofenac remained stable in the soil during a 21-day incubation period. Microarrays examined transcriptional changes at low and high diclofenac exposure concentrations. The results indicated that development and growth were severely hampered and immunity-related genes, mainly directed against bacteria and fungi, were significantly up-regulated. Furthermore, neural metabolic processes were significantly affected only at the high concentration. We conclude that diclofenac is toxic to non-target soil invertebrates, although its mode of action is different from the mammalian toxicity. The genetic markers proposed in this study may be promising early markers for diclofenac ecotoxicity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Temporal Dynamics of the Microbial Community Composition with a Focus on Toxic Cyanobacteria and Toxin Presence during Harmful Algal Blooms in Two South German Lakes

    PubMed Central

    Scherer, Pia I.; Millard, Andrew D.; Miller, Andreas; Schoen, Renate; Raeder, Uta; Geist, Juergen; Zwirglmaier, Katrin

    2017-01-01

    variants detected were microcystin-LR, -RR, and -YR. The maximum microcystin concentrations measured was 6.7 μg/L, a value still acceptable for recreational waters but not drinking water. Microcystin concentration correlated positively with total phosphorus and mcyB copy number. We identified low abundant Microcystis sp. as the only microcystin producer in both lakes. Therefore, risk assessment efforts need to take into account the fact that non-dominant species may cause toxicity of the blooms observed. PMID:29255452

  13. Acute aquatic toxicity of biodiesel fuels

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wright, B.; Haws, R.; Little, D.

    1995-12-31

    This study develops data on the acute aquatic toxicity of selected biodiesel fuels which may become subject to environmental effects test regulations under the US Toxic Substances Control Act (TSCA). The test substances are Rape Methyl Ester (RME), Rape Ethyl Ester (REE), Methyl Soyate (MS), a biodiesel mixture of 20% REE and 80% Diesel, a biodiesel mixture of 50% REE and diesel, and a reference substance of Phillips D-2 Reference Diesel. The test procedure follows the Daphnid Acute Toxicity Test outlined in 40 CFR {section} 797.1300 of the TSCA regulations. Daphnia Magna are exposed to the test substance in amore » flow-through system consisting of a mixing chamber, a proportional diluter, and duplicate test chambers. Novel system modifications are described that accommodate the testing of oil-based test substances with Daphnia. The acute aquatic toxicity is estimated by an EC50, an effective concentration producing immobility in 50% of the test specimen.« less

  14. A Study on the D. magna and V. fischeri Toxicity Relationship of Industrial Wastewater from Korea

    NASA Astrophysics Data System (ADS)

    Pyo, S.; Lee, S.; Chun Sang, H.; Park, T. J.; Kim, M. S.

    2015-12-01

    It is well known that high concentration of TDS (total dissolved solid) in industrial effluent gives rise to the toxicity to the Daphnia magna toxicity test. D. magna is vulnerable to relatively low TDS concentration showing the 24-hr EC50 of Salinity 0.6% (as the sea salt concentration). Recently, standard mandatory toxicity testing using Daphnia magna has been used to monitor industrial effluent toxicity according to Korea standard method (Acute Toxicity Test Method of the Daphnia magna Straus (Cladocera, Crustacea), ES 04704. 1a) under regulation. Since only one acute toxicity testing is applied in the present, we are trying to introduce microbial battery for more complete toxicity assessment. In this study, the acute toxicities between daphnids and microbes were compared. The results of D. magna and Vibrio fischeri toxicity test from 165 industrial wastewater effluents showed high positive correlation. In addition, the possibility of predicting daphnia toxicity from the bacterial toxicity data amounts to 92.6% if we consider salinity effect (>5ppt) together. From this study, we found that the V. fischeri toxicity test is a powerful battery tool to assess the industrial wastewater toxicity. Here, we suggest that luminescent bacteria toxicity test be useful not only for complete toxicity assessment which can't be obtained by daphnia toxicity testing only but also for the reduction cost, time, and labor in the Korean society. Keywords : D. magna, V. fischeri, Industrial waste water, battery test Acknowledgement This research was supported by a grant (15IFIP-B089908-02) from Plant Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government

  15. Acute toxicity tests and meta-analysis identify gaps in tropical ecotoxicology for amphibians.

    PubMed

    Ghose, Sonia L; Donnelly, Maureen A; Kerby, Jacob; Whitfield, Steven M

    2014-09-01

    Amphibian populations are declining worldwide, particularly in tropical regions where amphibian diversity is highest. Pollutants, including agricultural pesticides, have been identified as a potential contributor to decline, yet toxicological studies of tropical amphibians are very rare. The present study assesses toxic effects on amphibians of 10 commonly used commercial pesticides in tropical agriculture using 2 approaches. First, the authors conducted 8-d toxicity assays with formulations of each pesticide using individually reared red-eyed tree frog (Agalychnis callidryas) tadpoles. Second, they conducted a review of available data for the lethal concentration to kill 50% of test animals from the US Environmental Protection Agency's ECOTOX database to allow comparison with their findings. Lethal concentration estimates from the assays ranged over several orders of magnitude. The nematicides terbufos and ethoprophos and the fungicide chlorothalonil were very highly toxic, with evident effects within an order of magnitude of environmental concentrations. Acute toxicity assays and meta-analysis show that nematicides and fungicides are generally more toxic than herbicides yet receive far less research attention than less toxic herbicides. Given that the tropics have a high diversity of amphibians, the findings emphasize the need for research into the effects of commonly used pesticides in tropical countries and should help guide future ecotoxicological research in tropical regions. © 2014 SETAC.

  16. Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking)

    USDA-ARS?s Scientific Manuscript database

    Fumonisins are found in corn. They are toxic to animals, cause cancer in rodents, and neural tube defects in LM/Bc mice. Reducing their concentrations in corn-based foods is therefore desirable. Chemical analysis or in vitro bioassays of food extracts might not detect toxic fumonisin reaction pro...

  17. Acute and early life stage toxicity of industrial effluent on Japanese medaka (Oryzias latipes).

    PubMed

    Zha, Jinmiao; Wang, Zijian

    2006-03-15

    To develop the whole effluent toxicity testing methods (WET), embryo larval stage toxicity test using Japanese medaka (Oryzias latipes) was conducted to evaluate an effluent from a banknote printing plant (BPP). The method is based on acute toxicity using endpoint of 96-h larval morality and on chronic toxicity using endpoints such as the time to hatch, hatching success, deformity, growth rate, swim-up failure, accumulative mortality and sexual ratio. In test for 96-h larval mortality, LC50 (the concentration was lethal to 50% of newly hatching medaka larvae) was 72.9%. In chronic toxicity test, newly fertilized embryos (<5-h old) were exposed to 1%, 6.25%, 12.5%, 25%, 50% effluent concentrations and to 200 mug/l BPA in a 24-h static renewal system at 25+/-1 degrees C until 15 day post-hatch. The results showed that all chronic endpoints were significantly different from the control at 50% dilution (p < 0.01). Embryos began to show lesions on 4th day at higher concentrations (12.5%, 25%, 50% BPP effluent concentrations). Treatment group of 25% dilution showed delayed time to hatch. A reduction in body weight was observed at 25% dilutions for males and females, respectively. Deformities were observed in newly hatched larvae at 25% and 50% BPP effluent concentrations. At 25% dilution, sex ratio of larvae was alternated and there was feminization phenomenon. We conclude that embryo larval stage test using medaka is feasible to evaluate both acute and chronic toxicities and potential endocrine disrupting activity of industrial effluents.

  18. A MODE-OF-ACTION-BASED QSAR APPROACH TO IMPROVE UNDERSTANDING OF DEVELOPMENTAL TOXICITY

    EPA Science Inventory

    QSAR models of developmental toxicity (devtox) have met with limited regulatory acceptance due to the use of ill-defined endpoints, lack of biological interpretability, and poor model performance. More generally, the lack of biological inference of many QSAR models is often due t...

  19. A confirmed case of toxic shock syndrome associated with the use of a menstrual cup

    PubMed Central

    Mitchell, Michael A; Bisch, Steve; Arntfield, Shannon; Hosseini-Moghaddam, Seyed M

    2015-01-01

    Menstrual cups have been reported to be an acceptable substitute for tampons. These flexible cups have also been reported to provide a sustainable solution to menstrual management, with modest cost savings and no significant health risk. The present article documents the first case of toxic shock syndrome associated with the use of a menstrual cup in a woman 37 years of age, using a menstrual cup for the first time. Toxic shock syndrome and the literature on menstrual cups is reviewed and a possible mechanism for the development of toxic shock syndrome in the patient is described. PMID:26361491

  20. A confirmed case of toxic shock syndrome associated with the use of a menstrual cup.

    PubMed

    Mitchell, Michael A; Bisch, Steve; Arntfield, Shannon; Hosseini-Moghaddam, Seyed M

    2015-01-01

    Menstrual cups have been reported to be an acceptable substitute for tampons. These flexible cups have also been reported to provide a sustainable solution to menstrual management, with modest cost savings and no significant health risk. The present article documents the first case of toxic shock syndrome associated with the use of a menstrual cup in a woman 37 years of age, using a menstrual cup for the first time. Toxic shock syndrome and the literature on menstrual cups is reviewed and a possible mechanism for the development of toxic shock syndrome in the patient is described.

  1. California wildfires of 2008: coarse and fine particulate matter toxicity.

    PubMed

    Wegesser, Teresa C; Pinkerton, Kent E; Last, Jerold A

    2009-06-01

    During the last week of June 2008, central and northern California experienced thousands of forest and brush fires, giving rise to a week of severe fire-related particulate air pollution throughout the region. California experienced PM(10-2.5) (particulate matter with mass median aerodynamic diameter > 2.5 mum to < 10 mum; coarse ) and PM(2.5) (particulate matter with mass median aerodynamic diameter < 2.5 mum; fine) concentrations greatly in excess of the air quality standards and among the highest values reported at these stations since data have been collected. These observations prompt a number of questions about the health impact of exposure to elevated levels of PM(10-2.5) and PM(2.5) and about the specific toxicity of PM arising from wildfires in this region. Toxicity of PM(10-2.5) and PM(2.5) obtained during the time of peak concentrations of smoke in the air was determined with a mouse bioassay and compared with PM samples collected under normal conditions from the region during the month of June 2007. Concentrations of PM were not only higher during the wildfire episodes, but the PM was much more toxic to the lung on an equal weight basis than was PM collected from normal ambient air in the region. Toxicity was manifested as increased neutrophils and protein in lung lavage and by histologic indicators of increased cell influx and edema in the lung. We conclude that the wildfire PM contains chemical components toxic to the lung, especially to alveolar macrophages, and they are more toxic to the lung than equal doses of PM collected from ambient air from the same region during a comparable season.

  2. Sludge batch 9 (SB9) acceptance evaluation. Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bannochie, C. J.; Diprete, D. P.; Pareizs, J. M.

    Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a composition expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

  3. The Role of Nitrogen Fixation in Cyanobacterial Bloom Toxicity in a Temperate, Eutrophic Lake

    PubMed Central

    Beversdorf, Lucas J.; Miller, Todd R.; McMahon, Katherine D.

    2013-01-01

    Toxic cyanobacterial blooms threaten freshwaters worldwide but have proven difficult to predict because the mechanisms of bloom formation and toxin production are unknown, especially on weekly time scales. Water quality management continues to focus on aggregated metrics, such as chlorophyll and total nutrients, which may not be sufficient to explain complex community changes and functions such as toxin production. For example, nitrogen (N) speciation and cycling play an important role, on daily time scales, in shaping cyanobacterial communities because declining N has been shown to select for N fixers. In addition, subsequent N pulses from N2 fixation may stimulate and sustain toxic cyanobacterial growth. Herein, we describe how rapid early summer declines in N followed by bursts of N fixation have shaped cyanobacterial communities in a eutrophic lake (Lake Mendota, Wisconsin, USA), possibly driving toxic Microcystis blooms throughout the growing season. On weekly time scales in 2010 and 2011, we monitored the cyanobacterial community in a eutrophic lake using the phycocyanin intergenic spacer (PC-IGS) region to determine population dynamics. In parallel, we measured microcystin concentrations, N2 fixation rates, and potential environmental drivers that contribute to structuring the community. In both years, cyanobacterial community change was strongly correlated with dissolved inorganic nitrogen (DIN) concentrations, and Aphanizomenon and Microcystis alternated dominance throughout the pre-toxic, toxic, and post-toxic phases of the lake. Microcystin concentrations increased a few days after the first significant N2 fixation rates were observed. Then, following large early summer N2 fixation events, Microcystis increased and became most abundant. Maximum microcystin concentrations coincided with Microcystis dominance. In both years, DIN concentrations dropped again in late summer, and N2 fixation rates and Aphanizomenon abundance increased before the lake mixed in

  4. Response of nitrogen metabolism to boron toxicity in tomato plants.

    PubMed

    Cervilla, L M; Blasco, B; Ríos, J J; Rosales, M A; Rubio-Wilhelmi, M M; Sánchez-Rodríguez, E; Romero, L; Ruiz, J M

    2009-09-01

    Boron (B) toxicity has become important in areas close to the Mediterranean Sea where intensive agriculture has been developed. The objective of this research was to study the effects of B toxicity (0.5 mM and 2.0 mM B) on nitrogen (N) assimilation of two tomato cultivars that are often used in these areas. Leaf biomass, relative leaf growth rate (RGR(L)), concentration of B, nitrate (NO(3) (-)), ammonium (NH(4) (+)), organic N, amino acids and soluble proteins, as well as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthase (GS), glutamate synthetase (GOGAT) and glutamate dehydrogenase (GDH) activities were analysed in leaves. Boron toxicity significantly decreased leaf biomass, RGR(L), organic N, soluble proteins, and NR and NiR activities. The lowest NO(3) (-) and NH(4) (+) concentration in leaves was recorded when plants were supplied with 2.0 mM B in the root medium. Total B, amino acids, activities of GS, GOGAT and GDH increased under B toxicity. Data from the present study prove that B toxicity causes inhibition of NO(3) (-) reduction and increases NH(4) (+) assimilation in tomato plants.

  5. Haloactamides versus halomethanes formation and toxicity in chloraminated drinking water.

    PubMed

    Yang, Fan; Zhang, Jing; Chu, Wenhai; Yin, Daqiang; Templeton, Michael R

    2014-06-15

    In this study we quantified the concentrations of nine haloacetamides (HAcAms) and nine halomethanes (HMs) in the final waters of five drinking water treatment plants (DWTPs) that use either chlorination or chloramination for disinfection and evaluated the toxicity of dichloroacetamide (DCAcAm) and dichloromethane (DCM) in normal rat kidney (NRK) cells using four in vitro toxicity assays. All the DWTPs final waters contained primarily di-HAcAms, followed by tri- and mono-HAcAms, and DCAcAm was the most abundant species of the 9 HAcAms, regardless of chlorination or chloramination being applied. In the final waters of DWTPs using chlorination, tri-HMs (trihalomethanes, THMs) accounted for the majority of HMs, whereas chloramination resulted in more di-HMs (especially DCM) than THMs. All four in vitro toxicity assays indicated that the NRK cell chronic cytotoxicity and acute genotoxicity of DCAcAm were substantially higher than that of DCM. In view of observed occurrence concentrations and quantified toxicity levels, the findings of this study suggest that DCAcAm represents a higher toxicity risk than DCM in chloraminated drinking waters. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Effect of toxicity of Ag nanoparticles on SERS spectral variance of bacteria

    NASA Astrophysics Data System (ADS)

    Cui, Li; Chen, Shaode; Zhang, Kaisong

    2015-02-01

    Ag nanoparticles (NPs) have been extensively utilized in surface-enhanced Raman scattering (SERS) spectroscopy for bacterial identification. However, Ag NPs are toxic to bacteria. Whether such toxicity can affect SERS features of bacteria and interfere with bacterial identification is still unknown and needed to explore. Here, by carrying out a comparative study on non-toxic Au NPs with that on toxic Ag NPs, we investigated the influence of nanoparticle concentration and incubation time on bacterial SERS spectral variance, both of which were demonstrated to be closely related to the toxicity of Ag NPs. Sensitive spectral alterations were observed on Ag NPs with increase of NPs concentration or incubation time, accompanied with an obvious decrease in number of viable bacteria. In contrast, SERS spectra and viable bacterial number on Au NPs were rather constant under the same conditions. A further analysis on spectral changes demonstrated that it was cell response (i.e. metabolic activity or death) to the toxicity of Ag NPs causing spectral variance. However, biochemical responses to the toxicity of Ag were very different in different bacteria, indicating the complex toxic mechanism of Ag NPs. Ag NPs are toxic to a great variety of organisms, including bacteria, fungi, algae, protozoa etc., therefore, this work will be helpful in guiding the future application of SERS technique in various complex biological systems.

  7. Boron toxicity is alleviated by hydrogen sulfide in cucumber (Cucumis sativus L.) seedlings.

    PubMed

    Wang, Bao-Lan; Shi, Lei; Li, Yin-Xing; Zhang, Wen-Hao

    2010-05-01

    Boron (B) is an essential micronutrient for plants, which when occurs in excess in the growth medium, becomes toxic to plants. Rapid inhibition of root elongation is one of the most distinct symptoms of B toxicity. Hydrogen sulfide (H(2)S) is emerging as a potential messenger molecule involved in modulation of physiological processes in plants. In the present study, we investigated the role of H(2)S in B toxicity in cucumber (Cucumis sativus) seedlings. Root elongation was significantly inhibited by exposure of cucumber seedlings to solutions containing 5 mM B. The inhibitory effect of B on root elongation was substantially alleviated by treatment with H(2)S donor sodium hydrosulfide (NaHS). There was an increase in the activity of pectin methylesterase (PME) and up-regulated expression of genes encoding PME (CsPME) and expansin (CsExp) on exposure to high B concentration. The increase in PME activity and up-regulation of expression of CsPME and CsExp induced by high B concentration were markedly reduced in the presence of H(2)S donor. There was a rapid increase in soluble B concentrations in roots on exposure to high concentration B solutions. Treatment with H(2)S donor led to a transient reduction in soluble B concentration in roots such that no differences in soluble B concentrations in roots in the absence and presence of NaHS were found after 8 h exposure to the high concentration B solutions. These findings suggest that increases in activities of PME and expansin may underlie the inhibition of root elongation by toxic B, and that H(2)S plays an ameliorative role in protection of plants from B toxicity by counteracting B-induced up-regulation of cell wall-associated proteins of PME and expansins.

  8. SEDIMENT TOXICITY AS AN INDICATOR OF CONTAMINANT STRESS IN EMAP-ESTUARIES

    EPA Science Inventory

    Toxicity of sediments is widely used in EPA, ACOE, and NOAA monitoring and regulatory programs as a complement to measuring of chemical concentrations as it provides an indication of the bioavailability of sediment contaminants. Sediment toxicity was included as an abiotic condit...

  9. Advanced oxidation treatment of pulp mill effluent for TOC and toxicity removals.

    PubMed

    Catalkaya, Ebru Cokay; Kargi, Fikret

    2008-05-01

    Pulp mill effluent was treated by different advanced oxidation processes (AOPs) consisting of UV, UV/H2O2, TiO2-assisted photo-catalysis (UV/TiO2) and UV/H2O2/TiO2 in lab-scale reactors for total organic carbon (TOC) and toxicity removals. Effects of some operating parameters such as the initial pH, oxidant and catalyst concentrations on TOC and toxicity removals were investigated. Almost every method resulted in some degree of TOC and toxicity removal from the pulp mill effluent. However, the TiO2-assisted photo-catalysis (UV/TiO2) resulted in the highest TOC and toxicity removals under alkaline conditions when compared with the other AOPs tested. Approximately, 79.6% TOC and 94% toxicity removals were obtained by the TiO2-assisted photo-catalysis (UV/TiO2) with a titanium dioxide concentration of 0.75gl(-1) at pH 11 within 60min.

  10. Determination of heavy metal toxicity of finished leather solid waste.

    PubMed

    Aslan, Ahmet

    2009-05-01

    This paper investigates the toxicity in leather products of heavy metals known to be detrimental to the ecosystem. Heavy metal concentrations in leather samples were identified with ICP-OES, and toxicity was determined using a MetPLATE bioassay. Chromium and aluminium were found to constitute 98% of the total concentration of heavy metals in finished leather tanned with chromium and aluminium salts, while in some vegetable-tanned leather, zirconium was the only heavy metal identified. The average inhibition values for chromium, aluminium and vegetable tanned leather were 98.08%, 97.04% and 62.36%, respectively.

  11. Occurrence and concentrations of selected trace elements, halogenated organic compounds, and polycyclic aromatic hydrocarbons in streambed sediments and results of water-toxicity testing in Westside Creeks and the San Antonio River, San Antonio, Texas, 2014

    USGS Publications Warehouse

    Crow, Cassi L.; Wilson, Jennifer T.; Kunz, James L.

    2016-12-01

    Sediment samples and samples for water-toxicity testing were collected during 2014 from several streams in San Antonio, Texas, known locally as the Westside Creeks (Alazán, Apache, Martínez, and San Pedro Creeks) and from the San Antonio River. Samples were collected during base flow and after periods of stormwater runoff (poststorm conditions) to determine baseline sediment- and water-quality conditions. Streambed-sediment samples were analyzed for selected constituents, including trace elements and organic contaminants such as pesticides, polychlorinated biphenyls (PCBs), brominated flame retardants, and polycyclic aromatic hydrocarbons (PAHs). Potential risks of contaminants in sediment were evaluated by comparing concentrations of contaminants in sediment to two effects-based sediment-quality guidelines: (1) a lower level, called the threshold effect concentration, below which, harmful effects to benthic biota are not expected, and (2) a higher level, the probable effect concentration (PEC), above which harmful effects are expected to occur frequently. Samples for water-toxicity testing were collected from each stream to provide information about fish toxicity in the study area. The trace metal lead was detected at potentially toxic concentrations greater than the PEC in both the base-flow and poststorm samples collected at two sites sampled on San Pedro Creek. The PECs for the pesticides dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene, dichlorodiphenyltrichloroethane, and chlordane were exceeded in some of the samples at the same two sites on San Pedro Creek. Brominated flame retardants and polybrominated diphenyl ether (PBDE) 85, 153, and 154 were found in all streambed-sediment samples. Federal Environmental Quality Guidelines established by Environment Canada for PBDE 99 and PBDE 100 were exceeded in all samples in which PBDE 99 was detected and in a majority of the samples in which PBDE 100 was detected; the greatest concentrations

  12. Tropospheric ozone toxicity vs. usefulness of ozone therapy.

    PubMed

    Bocci, Velio Alvaro

    2007-02-01

    There is a general consensus that continuous inhalation of air polluted with ozone is detrimental for the lungs and vital organs. Even if the concentration of tropospheric ozone is slightly above the tolerated dose, toxicity ensues owing to the cumulative dose inhaled for months. However, in medicine ozone is used as a real drug and a precise concentration and therapeutic dosage must be calibrated against the antioxidant capacity of blood. As ozone reacts with blood, it generates pharmacological messengers such as H(2)O(2) and lipid oxidation products (LOPs). These activate several biochemical pathways in blood cells, which after reinfusion are responsible for therapeutic activities lasting several days. Neither acute nor chronic toxicity has been registered.

  13. 40 CFR 797.1600 - Fish early life stage toxicity test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the test solution concentrations. The test terminates following 60 days of post-hatch exposure (for an... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Fish early life stage toxicity test... Fish early life stage toxicity test. (a) Purpose. This guideline is intended to be used for assessing...

  14. 40 CFR 797.1600 - Fish early life stage toxicity test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the test solution concentrations. The test terminates following 60 days of post-hatch exposure (for an... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Fish early life stage toxicity test... Fish early life stage toxicity test. (a) Purpose. This guideline is intended to be used for assessing...

  15. Biochar application to hardrock mine tailings: Soil quality, microbial activity, and toxic element sorption

    USGS Publications Warehouse

    Kelly, Charlene N.; Peltz, Christopher D.; Stanton, Mark R.; Rutherford, David W.; Rostad, Colleen E.

    2014-01-01

    Waste rock piles from historic mining activities remain unvegetated as a result of metal toxicity and high acidity. Biochar has been proposed as a low-cost remediation strategy to increase soil pH and reduce leaching of toxic elements, and improve plant establishment. In this laboratory column study, biochar made from beetle-killed pine wood was assessed for utility as a soil amendment by mixing soil material from two mine sites collected near Silverton, Colorado, USA with four application rates of biochar (0%, 10%, 20%, 30% vol:vol). Columns were leached seven times over 65 days and leachate pH and concentration of toxic elements and base cations were measured at each leaching. Nutrient availability and soil physical and biological parameters were determined following the incubation period. We investigated the hypotheses that biochar incorporation into acidic mine materials will (1) reduce toxic element concentrations in leaching solution, (2) improve soil parameters (i.e. increase nutrient and water holding capacity and pH, and decrease compaction), and (3) increase microbial populations and activity. Biochar directly increased soil pH (from 3.33 to 3.63 and from 4.07 to 4.77 in the two materials) and organic matter content, and decreased bulk density and extractable salt content in both mine materials, and increased nitrate availability in one material. No changes in microbial population or activity were detected in either mine material upon biochar application. In leachate solution, biochar increased base cations from both materials and reduced the concentrations of Al, Cd, Cu, Pb, and Zn in leachate solution from one material. However, in the material with greater toxic element content, biochar did not reduce concentrations of any measured dissolved toxic elements in leachate and resulted in a potentially detrimental release of Cd and Zn into solution at concentrations above that of the pure mine material. The length of time of effectiveness and specific

  16. Comparative effects of fumonisins on sphingolipid metabolism and toxicity in ducks and turkeys.

    PubMed

    Benlasher, Emad; Geng, Xiuyu; Nguyen, Ngoc Thanh Xuan; Tardieu, Didier; Bailly, Jean-Denis; Auvergne, Alain; Guerre, Philippe

    2012-03-01

    Fumonisins (FBs) are mycotoxins that are found worldwide in maize and maize products. Their main toxic effects have been well characterized in poultry, but differences between species have been demonstrated. Ducks appeared very sensitive to toxicity, whereas turkeys are more resistant. At the same time, alterations of sphingolipid metabolism, with an increase of the concentration of the free sphinganine (Sa) in serum and liver, have been demonstrated in the two species, but the link between the toxicity of FBs and Sa accumulation remains difficult to interpret. The aim of the present work was to compare the effects of FBs (10 mg FB1 + FB2/kg body weight) on sphingolipid metabolism in ducks and turkeys. Growth, feed consumption, and serum biochemistry were also investigated to evaluate toxicity. The main results showed that FBs increased Sa concentrations in liver and serum in ducks and turkeys, but these accumulations were not directly correlated with toxicity. Sa accumulation was higher in the livers of turkeys than in ducks, whereas Sa levels were higher in the sera of ducks than in turkeys. Hepatic toxicity was more pronounced in ducks than in turkeys and accompanied a decrease of body weight and an increase of serum biochemistry in ducks but not in turkeys. So, although FBs increase Sa concentration in the livers of both species, this effect is not directly proportional to toxicity. The mechanisms of FB toxicity and/or the mechanisms of protection of ducks and turkeys to the Sa accumulation within the liver remain to be established.

  17. MODULATING STORM DRAIN FLOWS TO REDUCE STREAM POLLUTANT CONCENTRATIONS

    EPA Science Inventory

    Pathogen and toxic chemical concentrations above the chemical and toxicity water quality standards in creeks and rivers pose risks to human health and aquatic ecosystems. Storm drains discharging into these watercourses often contribute significantly to elevating pollutant concen...

  18. A high-gain, compact, nonimaging concentrator: RXI.

    PubMed

    Miñano, J C; Gonźlez, J C; Benítez, P

    1995-12-01

    The design procedure of a new nonimaging concentrator (called an RXI) is explained. Rays that impinge on the concentrator aperture, within the acceptance angle, are directed to the receiver by means of one refraction, one reflection, and one total internal reflection. The concentrator can be made as a single dielectric piece (in which the receiver is immersed) whose aspect ratio (thickness/aperture diameter) is close to 1/3. Ray-tracing analysis of a rotational symmetric RXI shows total transmissions of greater than 94.5% (no absorption or reflection losses are considered) when the acceptance angle of the incoming rays is small (<3°) and when the receiver area is the smallest possible (maximal concentration.).

  19. Toxicity assessment of sediments from the Grand Calumet River and Indiana Harbor Canal in northwestern Indiana, USA

    USGS Publications Warehouse

    Ingersoll, C.G.; MacDonald, D.D.; Brumbaugh, W.G.; Johnson, B. Thomas; Kemble, N.E.; Kunz, J.L.; May, T.W.; Wang, N.; Smith, J.R.; Sparks, D.W.; Ireland, D.S.

    2002-01-01

    The objective of this study was to evaluate the toxicity of sediments from the Grand Calumet River and Indiana Harbor Canal located in northwestern Indiana, USA. Toxicity tests used in this assessment included 10-day sediment exposures with the amphipod Hyalella azteca, 31-day sediment exposures with the oligochaete Lumbriculus variegatus, and the Microtox® Solid-Phase Sediment Toxicity Test. A total of 30 sampling stations were selected in locations that had limited historic matching toxicity and chemistry data. Toxic effects on amphipod survival were observed in 60% of the samples from the assessment area. Results of a toxicity test with oligochaetes indicated that sediments from the assessment area were too toxic to be used in proposed bioaccumulation testing. Measurement of amphipod length after the 10-day exposures did not provide useful information beyond that provided by the survival endpoint. Seven of the 15 samples that were identified as toxic in the amphipod tests were not identified as toxic in the Microtox test, indicating that the 10-day H. azteca test was more sensitive than the Microtox test. Samples that were toxic tended to have the highest concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). The toxic samples often had an excess of simultaneously extracted metals (SEM) relative to acid volatile sulfide (AVS) and had multiple exceedances of probable effect concentrations (PECs). Metals may have contributed to the toxicity of samples that had both an excess molar concentration of SEM relative to AVS and elevated concentrations of metals in pore water. However, of the samples that had an excess of SEM relative to AVS, only 38% of these samples had elevated concentration of metals in pore water. The lack of correspondence between SEM-AVS and pore water metals indicates that there are variables in addition to AVS controlling the concentrations of metals in pore water. A mean PEC quotient of 3

  20. Mixture toxicity of the anti-inflammatory drugs diclofenac, ibuprofen, naproxen, and acetylsalicylic acid.

    PubMed

    Cleuvers, Michael

    2004-11-01

    The ecotoxicity of the nonsteroidal anti-inflammatory drugs (NSAIDs) diclofenac, ibuprofen, naproxen, and acetylsalicylic acid (ASA) has been evaluated using acute Daphnia and algal tests. Toxicities were relatively low, with half-maximal effective concentration (EC50) values obtained using Daphnia in the range from 68 to 166 mg L(-1) and from 72 to 626 mg L(-1) in the algal test. Acute effects of these substances seem to be quite improbable. The quantitative structure-activity relationships (QSAR) approach showed that all substances act by nonpolar narcosis; thus, the higher the n-octanol/water partitioning coefficient (log Kow) of the substances, the higher is their toxicity. Mixture toxicity of the compounds could be accurately predicted using the concept of concentration addition. Toxicity of the mixture was considerable, even at concentrations at which the single substances showed no or only very slight effects, with some deviations in the Daphnia test, which could be explained by incompatibility of the very steep dose-response curves and the probit analysis of the data. Because pharmaceuticals in the aquatic environment occur usually as mixtures, an accurate prediction of the mixture toxicity is indispensable for environmental risk assessment.

  1. Process for treating waste water having low concentrations of metallic contaminants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Looney, Brian B; Millings, Margaret R; Nichols, Ralph L

    A process for treating waste water having a low level of metallic contaminants by reducing the toxicity level of metallic contaminants to an acceptable level and subsequently discharging the treated waste water into the environment without removing the treated contaminants.

  2. Mapping polycyclic aromatic hydrocarbon and total toxicity equivalent soil concentrations by visible and near-infrared spectroscopy.

    PubMed

    Okparanma, Reuben N; Coulon, Frederic; Mayr, Thomas; Mouazen, Abdul M

    2014-09-01

    In this study, we used data from spectroscopic models based on visible and near-infrared (vis-NIR; 350-2500 nm) diffuse reflectance spectroscopy to develop soil maps of polycyclic aromatic hydrocarbons (PAHs) and total toxicity equivalent concentrations (TTEC) of the PAH mixture. The TTEC maps were then used for hazard assessment of three petroleum release sites in the Niger Delta province of Nigeria (5.317°N, 6.467°E). As the paired t-test revealed, there were non-significant (p > 0.05) differences between soil maps of PAH and TTEC developed with chemically measured and vis-NIR-predicted data. Comparison maps of PAH showed a slight to moderate agreement between measured and predicted data (Kappa coefficient = 0.19-0.56). Using proposed generic assessment criteria, hazard assessment showed that the degree of action for site-specific risk assessment and/or remediation is similar for both measurement methods. This demonstrates that the vis-NIR method may be useful for monitoring hydrocarbon contamination in a petroleum release site. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Toxicity of electronic waste leachates to Daphnia magna: screening and toxicity identification evaluation of different products, components, and materials.

    PubMed

    Lithner, Delilah; Halling, Maja; Dave, Göran

    2012-05-01

    Electronic waste has become one of the fastest growing waste problems in the world. It contains both toxic metals and toxic organics. The aim of this study was to (1) investigate to what extent toxicants can leach from different electronic products, components, and materials into water and (2) identify which group of toxicants (metals or hydrophobic organics) that is causing toxicity. Components from five discarded electronic products (cell phone, computer, phone modem, keyboard, and computer mouse) were leached in deionised water for 3 days at 23°C in concentrations of 25 g/l for metal components, 50 g/l for mixed-material components, and 100 g/l for plastic components. The water phase was tested for acute toxicity to Daphnia magna. Eighteen of 68 leachates showed toxicity (with immobility of D. magna ≥ 50% after 48 h) and came from metal or mixed-material components. The 8 most toxic leachates, with 48 h EC(50)s ranging from 0.4 to 20 g/l, came from 2 circuit sheets (key board), integrated drive electronics (IDE) cable clips (computer), metal studs (computer), a circuit board (computer mouse), a cord (phone modem), mixed parts (cell phone), and a circuit board (key board). All 5 electronic products were represented among them. Toxicity identification evaluations (with C18 and CM resins filtrations and ethylenediaminetetraacetic acid addition) indicated that metals caused the toxicity in the majority of the most toxic leachates. Overall, this study has shown that electronic waste can leach toxic compounds also during short-term leaching with pure water.

  4. Gaining Acceptance for the use of in vitro Toxicity Assays and QIVIVE in Regulatory Risk Assessment

    EPA Science Inventory

    Testing strategies are anticipated to increasingly rely on in vitro data as a basis to characterize early steps or key events in toxicity at relevant dose levels in human tissues. This requires quantitative in vitro to in vivo extrapolation to characterize dose-response as a bas...

  5. Demonstration of a Non-Toxic Reaction Control Engine

    NASA Technical Reports Server (NTRS)

    Robinson, Philip J.; Turpin, Alicia A.; Veith, Eric M.

    2007-01-01

    T:hree non-toxic demonstration reaction control engines (RCE) were successfully tested at the Aerojet Sacramento facility under a technology contract sponsored by the National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC). The goals of the NASA MSFC contract (NAS8-01109) were to develop and expand the technical maturity of a non-toxic, on-orbit auxiliary propulsion system (APS) thruster under the auspices of the Exploration Systems Mission Directorate. The demonstration engine utilized Liquid Oxygen (LOX) and Ethanol as propellants to produce 870 lbf thrust. The Aerojet RCE's were successfully acceptance tested over a broad range of operating conditions. Steady state tests evaluated engine response to varying chamber pressures and mixture ratios. In addition to the steady state tests, a variety of pulsing tests were conducted over a wide range of electrical pulse widths (EPW). Each EPW condition was also tested over a range of percent duty cycles (DC), and bit impulse and pulsing specific impulse were determined for each of these conditions. Subsequent to acceptance testing at Aerojet, these three engines were delivered to the NASA White Sands Test Facility (WSTF) in April 2005 for incorporation into a cryogenic Auxiliary Propulsion System Test Bed (APSTB). The APSTB is a test article that will be utilized in an altitude test cell to simulate anticipated mission applications. The objectives of this APSTB testing included evaluation of engine performance over an extended duty cycle map of propellant pressure and temperature, as well as engine and system performance at typical mission duty cycles over extended periods of time. This paper provides acceptance test results and a status of the engine performance as part of the system level testing.

  6. DMPS reverts morphologic and mitochondrial damage in OK cells exposed to toxic concentrations of HgCl2.

    PubMed

    Carranza-Rosales, Pilar; Guzmán-Delgado, Nancy E; Cruz-Vega, Delia E; Balderas-Rentería, Isaías; Gandolfi, A Jay

    2007-05-01

    Mercuric chloride (HgCl(2)) is a highly toxic compound, which can cause nephrotoxic damage. In the present study effects of HgCl(2) on mitochondria integrity and energy metabolism, as well as antidotal effects of 2,3-dimercaptopropane-1-sulfonate (DMPS) were investigated in the opossum kidney derived cell line (OK). OK cell monolayers were incubated during 0, 1, 3, 6, and 9 h in serum-free culture medium containing 15 microM HgCl(2), either in the absence or in the presence of 60 microM DMPS in a 1:4 ratio. Intracellular ATP content, MTT reduction, and HSP70/HSP90 induction were studied; confocal, transmission electron microscopy, and light microscopy studies were also performed. For confocal analysis, a mitochondrial selective probe (MitoTracker Red CMXH2Ros) was used. Antioxidant activity of DMPS was also studied by the scavenging of the free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH) technique. A decrease of ATP content, an impaired ability to reduce tetrazolium, and dramatic changes on cellular and mitochondrial morphology, and energetic levels were found after either 6 or 9 h of HgCl(2) exposure. Increased expression of HSP90 and HSP70 were also seen. When OK cells were co-incubated with HgCl(2) and DMPS, cellular morphology, viability, intracellular ATP, and mitochondrial membrane potential were partially restored; a protective effect on mitochondrial morphology was also seen. DMPS also showed potent antioxidant activity in vitro. Mitochondrial protection could be the cellular mechanism mediated by DMPS in OK cells exposed to a toxic concentration of HgCl(2).

  7. Toxicity of tributyltin (TBT) to terrestrial organisms and its species sensitivity distribution.

    PubMed

    Silva, Patrícia V; Silva, Ana Rita R; Mendo, Sónia; Loureiro, Susana

    2014-01-01

    The contamination of the terrestrial environment by disposal of tributyltin (TBT) by contaminated harbour sediments, sewage sludge and/or biocide products has been raising concerns and it may pose a risk to soil invertebrates and plants. This study aimed to improve the amount and quality of data for TBT toxicity in soils in order to assess the ecological risk of TBT to the terrestrial ecosystems. For this, bioassays were performed with the species Porcellionides pruinosus, Folsomia candida, Brassica rapa and Triticum aestivum to evaluate the toxic effects of TBT (as chloride) on these species. Additionally, this study contributed to increase the amount of data concerning TBT toxicity on soil dwelling organisms. The results showed a dose-response relationship between TBT concentration and the increase of toxicity in all species tested. These results were collated with results from literature to construct species sensitivity distributions (SSDs) and to calculate the hazardous concentration at 5% (HC₅) for all data, for each type of soil and TBT formulation used. The HC₅ value for TBT in soil was 2.06 mg TBT/kg soil dw. Little information is available concerning the concentrations of TBT in soils. In addition the predicted no-effect concentration (PNEC) value was determined to be 30 μg/kg soil. Only one study was found referring to TBT contaminated soils, and where TBT concentrations were lower than 0.024 μg TBT/kg for the wetland soil. Therefore it can be concluded that the real TBT concentrations determined represent low risk for environmental effects. In conclusion, the construction of SSDs and the calculation of HC5 using all the data available showed to be a more suitable method rather than the construction of several SSDs for each soil and TBT types. Further investigations concerning TBT concentrations and toxicity on soil organisms need to be performed to increase data and improve risk calculations. © 2013.

  8. Nonimaging optical concentrators using graded-index dielectric.

    PubMed

    Zitelli, M

    2014-04-01

    A new generation of inhomogeneous nonimaging optical concentrators is proposed, able to achieve simultaneously high optical efficiency and acceptance solid angle at a given geometrical concentration factor. General design methods are given, and concentrators are numerically investigated and optimized.

  9. Toxicity of dissolved and precipitated aluminium to marine diatoms.

    PubMed

    Gillmore, Megan L; Golding, Lisa A; Angel, Brad M; Adams, Merrin S; Jolley, Dianne F

    2016-05-01

    Localised aluminium contamination can lead to high concentrations in coastal waters, which have the potential for adverse effects on aquatic organisms. This research investigated the toxicity of 72-h exposures of aluminium to three marine diatoms (Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus and Phaeodactylum tricornutum) by measuring population growth rate inhibition and cell membrane damage (SYTOX Green) as endpoints. Toxicity was correlated to the time-averaged concentrations of different aluminium size-fractions, operationally defined as <0.025μm filtered, <0.45μm filtered (dissolved) and unfiltered (total) present in solution over the 72-h bioassay. The chronic population growth rate inhibition after aluminium exposure varied between diatom species. C. closterium was the most sensitive species (10% inhibition of growth rate (72-h IC10) of 80 (55-100)μg Al/L (95% confidence limits)) while M. polymorphus (540 (460-600)μg Al/L) and P. tricornutum (2100 (2000-2200)μg Al/L) were less sensitive (based on measured total aluminium). Dissolved aluminium was the primary contributor to toxicity in C. closterium, while a combination of dissolved and precipitated aluminium forms contributed to toxicity in M. polymorphus. In contrast, aluminium toxicity to the most tolerant diatom P. tricornutum was due predominantly to precipitated aluminium. Preliminary investigations revealed the sensitivity of C. closterium and M. polymorphus to aluminium was influenced by initial cell density with aluminium toxicity significantly (p<0.05) increasing with initial cell density from 10(3) to 10(5)cells/mL. No effects on plasma membrane permeability were observed for any of the three diatoms suggesting that mechanisms of aluminium toxicity to diatoms do not involve compromising the plasma membrane. These results indicate that marine diatoms have a broad range in sensitivity to aluminium with toxic mechanisms related to both dissolved and precipitated

  10. Quantification of Toxic Effects for Water Concentration-based Aquatic Life Criteria -Part B

    EPA Science Inventory

    Erickson et al. (1991) conducted a series of experiments on the toxicity of pentachloroethane (PCE) to juvenile fathead minnows. These experiments included evaluations of bioaccumulation kinetics, the time-course of mortality under both constant and time-variable exposures, the r...

  11. Tracking pyrethroid toxicity in surface water samples: Exposure dynamics and toxicity identification tools for laboratory tests with Hyalella azteca (Amphipoda).

    PubMed

    Deanovic, Linda A; Stillway, Marie; Hammock, Bruce G; Fong, Stephanie; Werner, Inge

    2018-02-01

    Pyrethroid insecticides are commonly used in pest control and are present at toxic concentrations in surface waters of agricultural and urban areas worldwide. Monitoring is challenging as a result of their high hydrophobicity and low toxicity thresholds, which often fall below the analytical methods detection limits (MDLs). Standard daphnid bioassays used in surface water monitoring are not sensitive enough to protect more susceptible invertebrate species such as the amphipod Hyalella azteca and chemical loss during toxicity testing is of concern. In the present study, we quantified toxicity loss during storage and testing, using both natural and synthetic water, and presented a tool to enhance toxic signal strength for improved sensitivity of H. azteca toxicity tests. The average half-life during storage in low-density polyethylene (LDPE) cubitainers (Fisher Scientific) at 4 °C of 5 pyrethroids (permethrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, and esfenvalerate) and one organophosphate (chlorpyrifos; used as reference) was 1.4 d, and piperonyl butoxide (PBO) proved an effective tool to potentiate toxicity. We conclude that toxicity tests on ambient water samples containing these hydrophobic insecticides are likely to underestimate toxicity present in the field, and mimic short pulse rather than continuous exposures. Where these chemicals are of concern, the addition of PBO during testing can yield valuable information on their presence or absence. Environ Toxicol Chem 2018;37:462-472. © 2017 SETAC. © 2017 SETAC.

  12. Acute Toxicity of Tributyltins and Tributyltin Leachates from Marine Antibiofouling Paints.

    DTIC Science & Technology

    1982-09-10

    RO-0184 224 ACUTE TOXICITY OF TRIBUTYLTINS AND TRIBUTYLTIN i/I LEACHATES FROM MARINE ANTIBIOFOULING PAINTS(U) CALIFORNIA UNIV OAKLAND NAVAL...Classification) (U) ACUTE TOXICITY OF TRIBUTYLTINS AND TRIBUTYLTIN LEACHATES FROM MARINE ANTIBIOFOULING PAINTS 12, PERSO A UHR Laugin, Koy"., Linden, Olof and...xins causing acute toxicity or two amphipou species at concentrations as low as 10 g/L . Orchestia traskiana was exposed to bis ( tributyltin ) oxide

  13. Impact of water chemistry on the particle-specific toxicity of copper nanoparticles to Daphnia magna.

    PubMed

    Xiao, Yinlong; Peijnenburg, Willie J G M; Chen, Guangchao; Vijver, Martina G

    2018-01-01

    Toxicity of metallic nanoparticle suspensions (NP (total) ) is generally assumed to result from the combined effect of the particles present in suspensions (NP (particle) ) and their released ions (NP (ion) ). Evaluation and consideration of how water chemistry affects the particle-specific toxicity of NP (total) are critical for environmental risk assessment of nanoparticles. In this study, it was found that the toxicity of Cu NP (particle) to Daphnia magna, in line with the trends in toxicity for Cu NP (ion) , decreased with increasing pH and with increasing concentrations of divalent cations and dissolved organic carbon (DOC). Without the addition of DOC, the toxicity of Cu NP (total) to D. magna at the LC50 was driven mainly by Cu NP (ion) (accounting for ≥53% of the observed toxicity). However, toxicity of Cu NP (total) in the presence of DOC at a concentration ranging from 5 to 50mg C/L largely resulted from the NP (particle) (57%-85%), which could be attributable to the large reduction of the concentration of Cu NP (ion) and the enhancement of the stability of Cu NP (particle) when DOC was added. Our results indicate that water chemistry needs to be explicitly taken into consideration when evaluating the role of NP (particle) and NP (ion) in the observed toxicity of NP (total) . Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Evaluation of water treatment sludges toxicity using the Daphnia bioassay.

    PubMed

    Sotero-Santos, Rosana B; Rocha, Odete; Povinelli, Jurandyr

    2005-10-01

    Alum and ferric chloride sludges from two water treatment plants (WTPs) were analyzed regarding their physicochemical characteristics and toxicity to Daphnia similis. Experiments were carried out in the dry and rainy seasons. Acute and chronic toxicity was measured using survival and reproduction as measurement endpoints. No acute toxicity of the sludge was observed in 48 h exposure. Ferric chloride sludge caused chronic toxicity, demonstrated by low fecundity and some mortality, while alum sludge caused chronic toxicity characterized by low fecundity. Some sludge characteristics varied between samplings, including turbidity, solids contents, N, P and metal (Al and Fe) concentrations. These variables and the increase of chemical oxygen demand (COD) were identified as the main cause of degradation of the receiving waters. However, no relationship was observed between these variables and degree of toxicity. It is apparent from these results that water treatment sludges may be toxic and therefore may impair receiving waters. Alum sludge was less toxic than ferric chloride sludge.

  15. 40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

  16. 40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

  17. 40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

  18. 40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

  19. 40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

  20. US EPA - A*Star Partnership - Accelerating the Acceptance of ...

    EPA Pesticide Factsheets

    The path for incorporating new alternative methods and technologies into quantitative chemical risk assessment poses a diverse set of scientific challenges. Some of these challenges include development of relevant and predictive test systems and computational models to integrate and extrapolate experimental data, and rapid characterization and acceptance of these systems and models. The series of presentations will highlight a collaborative effort between the U.S. Environmental Protection Agency (EPA) and the Agency for Science, Technology and Research (A*STAR) that is focused on developing and applying experimental and computational models for predicting chemical-induced liver and kidney toxicity, brain angiogenesis, and blood-brain-barrier formation. In addressing some of these challenges, the U.S. EPA and A*STAR collaboration will provide a glimpse of what chemical risk assessments could look like in the 21st century. Presentation on US EPA – A*STAR Partnership at international symposium on Accelerating the acceptance of next-generation sciences and their application to regulatory risk assessment in Singapore.

  1. In vitro evidence of glucose-induced toxicity in GnRH secreting neurons: high glucose concentrations influence GnRH secretion, impair cell viability, and induce apoptosis in the GT1-1 neuronal cell line.

    PubMed

    Pal, Lubna; Chu, Hsiao-Pai; Shu, Jun; Topalli, Ilir; Santoro, Nanette; Karkanias, George

    2007-10-01

    To evaluate for direct toxic effects of high glucose concentrations on cellular physiology in GnRH secreting immortalized GT1-1 neurons. Prospective experimental design. In vitro experimental model using a cell culture system. GT1-1 cells were cultured in replicates in media with two different glucose concentrations (450 mg/dL and 100 mg/dL, respectively) for varying time intervals (24, 48, and 72 hours). Effects of glucose concentrations on GnRH secretion by the GT1-1 neurons were evaluated using a static culture model. Cell viability, cellular apoptosis, and cell cycle events in GT1-1 neurons maintained in two different glucose concentrations were assessed by flow cytometry (fluorescence-activated cell sorter) using Annexin V-PI staining. Adverse influences of high glucose concentrations on GnRH secretion and cell viability were noted in cultures maintained in high glucose concentration (450 mg/dL) culture medium for varying time intervals. A significantly higher percentage of cells maintained in high glucose concentration medium demonstrated evidence of apoptosis by a fluorescence-activated cell sorter. We provide in vitro evidence of glucose-induced cellular toxicity in GnRH secreting GT1-1 neurons. Significant alterations in GnRH secretion, reduced cell viability, and a higher percentage of apoptotic cells were observed in GT1-1 cells maintained in high (450 mg/dL) compared with low (100 mg/dL) glucose concentration culture medium.

  2. Cumulative toxicity of neonicotinoid insecticide mixtures to Chironomus dilutus under acute exposure scenarios.

    PubMed

    Maloney, Erin M; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

    2017-11-01

    Extensive agricultural use of neonicotinoid insecticide products has resulted in the presence of neonicotinoid mixtures in surface waters worldwide. Although many aquatic insect species are known to be sensitive to neonicotinoids, the impact of neonicotinoid mixtures is poorly understood. In the present study, the cumulative toxicities of binary and ternary mixtures of select neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) were characterized under acute (96-h) exposure scenarios using the larval midge Chironomus dilutus as a representative aquatic insect species. Using the MIXTOX approach, predictive parametric models were fitted and statistically compared with observed toxicity in subsequent mixture tests. Single-compound toxicity tests yielded median lethal concentration (LC50) values of 4.63, 5.93, and 55.34 μg/L for imidacloprid, clothianidin, and thiamethoxam, respectively. Because of the similar modes of action of neonicotinoids, concentration-additive cumulative mixture toxicity was the predicted model. However, we found that imidacloprid-clothianidin mixtures demonstrated response-additive dose-level-dependent synergism, clothianidin-thiamethoxam mixtures demonstrated concentration-additive synergism, and imidacloprid-thiamethoxam mixtures demonstrated response-additive dose-ratio-dependent synergism, with toxicity shifting from antagonism to synergism as the relative concentration of thiamethoxam increased. Imidacloprid-clothianidin-thiamethoxam ternary mixtures demonstrated response-additive synergism. These results indicate that, under acute exposure scenarios, the toxicity of neonicotinoid mixtures to C. dilutus cannot be predicted using the common assumption of additive joint activity. Indeed, the overarching trend of synergistic deviation emphasizes the need for further research into the ecotoxicological effects of neonicotinoid insecticide mixtures in field settings, the development of better toxicity models for neonicotinoid mixture

  3. Horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications.

    PubMed

    Ma, Hongcai; Wu, Lin

    2015-07-10

    We present the design of a horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications. This solar concentrator consists of an array of telecentric primary concentrators, a horizontally staggered lightguide layer, and a vertically tapered lightguide layer. The primary concentrator is realized by two plano-aspheric lenses with lateral movement and maintains a high F-number over an angle range of ±23.5°. The results of the simulations show that the solar concentrator achieves a high concentration ratio of 500× with ±0.5° of acceptance angle by a single-axis tracker and dual lateral translation stages.

  4. Thin film concentrator panel development

    NASA Technical Reports Server (NTRS)

    Zimmerman, D. K.

    1982-01-01

    The development and testing of a rigid panel concept that utilizes a thin film reflective surface for application to a low-cost point-focusing solar concentrator is discussed. It is shown that a thin film reflective surface is acceptable for use on solar concentrators, including 1500 F applications. Additionally, it is shown that a formed steel sheet substrate is a good choice for concentrator panels. The panel has good optical properties, acceptable forming tolerances, environmentally resistant substrate and stiffeners, and adaptability to low to mass production rates. Computer simulations of the concentrator optics were run using the selected reflector panel design. Experimentally determined values for reflector surface specularity and reflectivity along with dimensional data were used in the analysis. The simulations provided intercept factor and net energy into the aperture as a function of aperture size for different surface errors and pointing errors. Point source and Sun source optical tests were also performed.

  5. Triclosan persistence through wastewater treatment plants and its potential toxic effects on river biofilms.

    PubMed

    Ricart, Marta; Guasch, Helena; Alberch, Mireia; Barceló, Damià; Bonnineau, Chloé; Geiszinger, Anita; Farré, Marinel la; Ferrer, Josep; Ricciardi, Francesco; Romaní, Anna M; Morin, Soizic; Proia, Lorenzo; Sala, Lluís; Sureda, David; Sabater, Sergi

    2010-11-15

    Triclosan is a commonly used bactericide that survives several degradation steps in WWTP (wastewater treatment plants) and potentially reaches fluvial ecosystems. In Mediterranean areas, where water scarcity results in low dilution capacity, the potential environmental risk of triclosan is high. A set of experimental channels was used to examine the short-term effects of triclosan (from 0.05 to 500μgL⁻¹) on biofilm algae and bacteria. Environmentally relevant concentrations of triclosan caused an increase of bacterial mortality with a no effect concentration (NEC) of 0.21μgL⁻¹. Dead bacteria accounted for up to 85% of the total bacterial population at the highest concentration tested. The toxicity of triclosan was higher for bacteria than algae. Photosynthetic efficiency was inhibited with increasing triclosan concentrations (NEC=0.42μgL⁻¹), and non-photochemical quenching mechanisms decreased. Diatom cell viability was also affected with increasing concentrations of triclosan. Algal toxicity may be a result of indirect effects on the biofilm toxicity, but the clear and progressive reduction observed in all the algal-related endpoints suggest the existence of direct effects of the bactericide. The toxicity detected on the co-occurring non-target components of the biofilm community, the capacity of triclosan to survive through WWTP processes and the low dilution capacity that characterizes Mediterranean systems extend the relevance of triclosan toxicity beyond bacteria in aquatic habitats. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Assessment of combined toxicity of heavy metals from industrial wastewaters on Photobacterium phosphoreum T3S

    NASA Astrophysics Data System (ADS)

    Zeb, BibiSaima; Ping, Zheng; Mahmood, Qaisar; Lin, Qiu; Pervez, Arshid; Irshad, Muhammad; Bilal, Muhammad; Bhatti, Zulfiqar Ahmad; Shaheen, Shahida

    2017-07-01

    This research work is focusing on the toxicities of heavy metals of industrial origin to anaerobic digestion of the industrial wastewater. Photobacterium phosphoreum T3S was used as an indicator organism. The acute toxicities of heavy metals on P. phosphoreum T3S were assessed during 15-min half inhibitory concentration (IC50) as indicator at pH 5.5-6. Toxicity assays involved the assessment of multicomponent mixtures using TU and MTI approaches. The results of individual toxicity indicated that the toxicity of Cd, Cu and Pb on P. phosphoreum increased with increasing concentrations and there was a linear correlation. The 15-min IC50 values of Cd, Cu and Pb were 0.537, 1.905 and 1.231 mg/L, respectively, and their toxic order was Cd > Pb > Cu. The combined effects of Cd, Cu and Pb were assayed by equivalent concentration mixing method. The results showed that the combined effects of Cd + Cu, Cd + Pb, Cu + Pb, Cd + Cu + Pb were antagonistic, antagonistic and partly additive. The combined effect of three heavy metals was partly additive.

  7. Toxicity of Silver Nanoparticles at the Air-Liquid Interface

    PubMed Central

    Holder, Amara L.; Marr, Linsey C.

    2013-01-01

    Silver nanoparticles are one of the most prevalent nanomaterials in consumer products. Some of these products are likely to be aerosolized, making silver nanoparticles a high priority for inhalation toxicity assessment. To study the inhalation toxicity of silver nanoparticles, we have exposed cultured lung cells to them at the air-liquid interface. Cells were exposed to suspensions of silver or nickel oxide (positive control) nanoparticles at concentrations of 2.6, 6.6, and 13.2 μg cm−2 (volume concentrations of 10, 25, and 50 μg ml−1) and to 0.7 μg cm−2 silver or 2.1 μg cm−2 nickel oxide aerosol at the air-liquid interface. Unlike a number of in vitro studies employing suspensions of silver nanoparticles, which have shown strong toxic effects, both suspensions and aerosolized nanoparticles caused negligible cytotoxicity and only a mild inflammatory response, in agreement with animal exposures. Additionally, we have developed a novel method using a differential mobility analyzer to select aerosolized nanoparticles of a single diameter to assess the size-dependent toxicity of silver nanoparticles. PMID:23484109

  8. The toxicity of different lead salts to Enchytraeus crypticus in relation to bioavailability in soil.

    PubMed

    Zhang, Lulu; Van Gestel, Cornelis A M

    2017-08-01

    The present study aimed to assess the bioavailability and toxicity of lead nitrate and lead chloride to Enchytraeus crypticus in a natural standard soil. Worms were exposed to Pb-spiked soil for 21 d, and survival and reproduction were related to total, 0.01 M CaCl 2 -extractable, and porewater Pb concentrations in the soil and internal concentrations in the surviving animals. The Pb availability for Pb(NO 3 ) 2 and PbCl 2 was similar, as confirmed by Langmuir and Freundlich isotherms. The Pb concentrations in surviving worms increased with increasing Pb concentrations in the soil and did not differ for the 2 Pb salts. Lead was toxic to E. crypticus at median lethal concentrations (LC50s) of 543 and 779 mg Pb/kg dry soil and median effect concentrations (EC50s) of 189 and 134 mg Pb/kg dry soil, for Pb(NO 3 ) 2 and PbCl 2 , respectively. Mortality of E. crypticus was related to internal Pb concentrations in the worms rather than to total or available Pb concentrations in the soil, whereas reproduction toxicity was better explained from Pb concentrations in 0.01 M CaCl 2 extracts or porewater of the test soil than from total Pb concentrations in the soil or Pb concentrations in the worms. Overall, the bioavailability and toxicity of Pb(NO 3 ) 2 and PbCl 2 to E. crypticus in LUFA 2.2 soil did not differ. Environ Toxicol Chem 2017;36:2083-2091. © 2017 SETAC. © 2017 SETAC.

  9. Carbon nanotubes enhanced the lead toxicity on the freshwater fish

    NASA Astrophysics Data System (ADS)

    Martinez, D. S. T.; Alves, O. L.; Barbieri, E.

    2013-04-01

    Carbon nanotubes are promising nanostructures for many applications in materials industry and biotechnology. However, it is mandatory to evaluate their toxicity and environmental implications. We evaluated nitric acid treated multiwalled carbon nanotubes (HNO3-MWCNT) toxicity in Nile tilapia (Oreochromis niloticus) and also the lead (Pb) toxicity modulation after the nanotube interaction. Industrial grade multiwalled carbon nanotubes [Ctube 100, CNT Co. Ltd] were treated with 9M HNO3 for 12h at 150°C to generate oxygenated groups on the nanotube surface, to improve water dispersion and heavy metal interaction. The HNO3-treated multiwalled carbon nanotubes were physico-chemically characterized by several techniques [e.g. TEM, FE-SEM, TGA, ζ-potential and Raman spectroscopy]. HNO3-MWCNT did not show toxicity on Nile tilapia when the concentration ranged from 0.1 to 3.0 mg/L, and the maximum exposure time was 96h. After 24, 48, 72 and 96h the LC50 values of Pb were 1.65, 1.32, 1.10 and 0.99 mg/L, respectively. To evaluate the Pb-nanotube interaction influence on the ecotoxicity, we submitted the Nile tilapia to different concentrations of Pb mixed with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, 96 h the LC50 values of Pb plus nanotubes were: 0.32, 0.25, 0.20, 0.18 mg/L, respectively. These values showed a synergistic effect after Pb-nanotube interaction since Pb toxicity increased over five times. X-ray energy dispersive spectroscopy (EDS) was used to confirm lead adsorption on the carbon nanotube oxidized surface. The exposure of Nile tilapia to Pb plus HNO3-MWCNT caused both oxygen consumption and ammonium excretion decrease, when compared to the control. Finally, our results show that carbon nanotubes interact with classical pollutants drawing attention to the environmental implications.

  10. Dose-finding designs using a novel quasi-continuous endpoint for multiple toxicities

    PubMed Central

    Ezzalfani, Monia; Zohar, Sarah; Qin, Rui; Mandrekar, Sumithra J; Deley, Marie-Cécile Le

    2013-01-01

    The aim of a phase I oncology trial is to identify a dose with an acceptable safety profile. Most phase I designs use the dose-limiting toxicity, a binary endpoint, to assess the unacceptable level of toxicity. The dose-limiting toxicity might be incomplete for investigating molecularly targeted therapies as much useful toxicity information is discarded. In this work, we propose a quasi-continuous toxicity score, the total toxicity profile (TTP), to measure quantitatively and comprehensively the overall severity of multiple toxicities. We define the TTP as the Euclidean norm of the weights of toxicities experienced by a patient, where the weights reflect the relative clinical importance of each grade and toxicity type. We propose a dose-finding design, the quasi-likelihood continual reassessment method (CRM), incorporating the TTP score into the CRM, with a logistic model for the dose–toxicity relationship in a frequentist framework. Using simulations, we compared our design with three existing designs for quasi-continuous toxicity score (the Bayesian quasi-CRM with an empiric model and two nonparametric designs), all using the TTP score, under eight different scenarios. All designs using the TTP score to identify the recommended dose had good performance characteristics for most scenarios, with good overdosing control. For a sample size of 36, the percentage of correct selection for the quasi-likelihood CRM ranged from 80% to 90%, with similar results for the quasi-CRM design. These designs with TTP score present an appealing alternative to the conventional dose-finding designs, especially in the context of molecularly targeted agents. PMID:23335156

  11. Toxicity potential of disinfection agent in tannery wastewater.

    PubMed

    Tisler, Tatjana; Zagorc-Koncan, Jana; Cotman, Magda; Drolc, Andreja

    2004-09-01

    Wastewater from a tannery was investigated using chemical-specific analyses and assessment of the acute toxicity of the whole effluent over a 2-year period. The wastewater samples were overloaded with organic and inorganic compounds, and measured concentrations of the chemical parameters as well as dilution factors estimating acute toxicity, frequently exceeded the permissible limits for the discharge of wastewater from a tannery into the receiving stream. In the later part of the monitoring programme, the toxicity of the samples was significantly increased in comparison to the previous samples. The agent for hide disinfection was assumed to be the reason for the increased toxicity of the wastewater samples, and the extremely high acute and chronic toxicity of the agent to bacteria, algae, daphnids, and fish confirmed this suspicion. The most sensitive species was Daphnia magna; the 48 h EC50 was 0.70 x 10(-5)v/v% and the 21d IC25 was 0.40 x 10(-6)v/v% of the agent. After withdrawal of this highly toxic agent for hide disinfection from the technological process in the tannery, the toxicity of the wastewater declined to the previous level.

  12. Development and application of a marine sediment pore-water toxicity test using Ulva fasciata zoospores

    USGS Publications Warehouse

    Hooten, Russell L.; Carr, R. Scott

    1998-01-01

    An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciatazoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH3) were conducted to determine zoospore sensitivity. Zoospore germination and gametophyte growth were as sensitive to SDS as sea urchin (Arbacia punctulata) fertilization and embryological development. Zoospore sensitivity to metals was greater than or comparable to that of adult macroalgae. Zoospores were less sensitive to NH3than were other commonly used toxicity test organisms. Test results using this algal assay with sediment pore-water samples with high NH3 concentrations were compared with results from sea urchin fertilization and embryological development tests for the same samples. Ulva fasciatazoospore germination was not affected by samples with high NH3 concentrations that were toxic in both sea urchin tests. Zoospore tolerance of NH3 and sensitivity to other contaminants indicate that their response may be useful in toxicity identification evaluation studies with pore-water samples that contain high concentrations of unionized NH3.

  13. Toxicity of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin to photoautotrophic aquatic organisms.

    PubMed

    Ebert, Ina; Bachmann, Jean; Kühnen, Ute; Küster, Anette; Kussatz, Carola; Maletzki, Dirk; Schlüter, Christoph

    2011-12-01

    The present study investigated the growth inhibition effect of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin on four photoautotrophic aquatic species: the freshwater microalga Desmodesmus subspicatus, the cyanobacterium Anabaena flos-aquae, the monocotyledonous macrophyte Lemna minor, and the dicotyledonous macrophyte Myriophyllum spicatum. Both antibiotics, which act by inhibiting the bacterial DNA gyrase, demonstrated high toxicity to A. flos-aquae and L. minor and moderate to slight toxicity to D. subspicatus and M. spicatum. The cyanobacterium was the most sensitive species with median effective concentration (EC50) values of 173 and 10.2 µg/L for enrofloxacin and ciprofloxacin, respectively. Lemna minor proved to be similarly sensitive, with EC50 values of 107 and 62.5 µg/L for enrofloxacin and ciprofloxacin, respectively. While enrofloxacin was more toxic to green algae, ciprofloxacin was more toxic to cyanobacteria. Calculated EC50s for D. subspicatus were 5,568 µg/L and >8,042 µg/L for enrofloxacin and ciprofloxacin, respectively. These data, as well as effect data from the literature, were compared with predicted and reported environmental concentrations. For two of the four species, a risk was identified at ciprofloxacin concentrations found in surface waters, sewage treatment plant influents and effluents, as well as in hospital effluents. For ciprofloxacin the results of the present study indicate a risk even at the predicted environmental concentration. In contrast, for enrofloxacin no risk was identified at predicted and measured concentrations. Copyright © 2011 SETAC.

  14. Boron Toxicity Causes Multiple Effects on Malus domestica Pollen Tube Growth.

    PubMed

    Fang, Kefeng; Zhang, Weiwei; Xing, Yu; Zhang, Qing; Yang, Liu; Cao, Qingqin; Qin, Ling

    2016-01-01

    Boron is an important micronutrient for plants. However, boron is also toxic to cells at high concentrations, although the mechanism of this toxicity is not known. This study aimed to evaluate the effect of boron toxicity on Malus domestica pollen tube growth and its possible regulatory pathway. Our results showed that a high concentration of boron inhibited pollen germination and tube growth and led to the morphological abnormality of pollen tubes. Fluorescent labeling coupled with a scanning ion-selective electrode technique detected that boron toxicity could decrease [Ca(2+)]c and induce the disappearance of the [Ca(2+)]c gradient, which are critical for pollen tube polar growth. Actin filaments were therefore altered by boron toxicity. Immuno-localization and fluorescence labeling, together with fourier-transform infrared analysis, suggested that boron toxicity influenced the accumulation and distribution of callose, de-esterified pectins, esterified pectins, and arabinogalactan proteins in pollen tubes. All of the above results provide new insights into the regulatory role of boron in pollen tube development. In summary, boron likely plays a structural and regulatory role in relation to [Ca(2+)]c, actin cytoskeleton and cell wall components and thus regulates Malus domestica pollen germination and tube polar growth.

  15. Boron Toxicity Causes Multiple Effects on Malus domestica Pollen Tube Growth

    PubMed Central

    Fang, Kefeng; Zhang, Weiwei; Xing, Yu; Zhang, Qing; Yang, Liu; Cao, Qingqin; Qin, Ling

    2016-01-01

    Boron is an important micronutrient for plants. However, boron is also toxic to cells at high concentrations, although the mechanism of this toxicity is not known. This study aimed to evaluate the effect of boron toxicity on Malus domestica pollen tube growth and its possible regulatory pathway. Our results showed that a high concentration of boron inhibited pollen germination and tube growth and led to the morphological abnormality of pollen tubes. Fluorescent labeling coupled with a scanning ion-selective electrode technique detected that boron toxicity could decrease [Ca2+]c and induce the disappearance of the [Ca2+]c gradient, which are critical for pollen tube polar growth. Actin filaments were therefore altered by boron toxicity. Immuno-localization and fluorescence labeling, together with fourier-transform infrared analysis, suggested that boron toxicity influenced the accumulation and distribution of callose, de-esterified pectins, esterified pectins, and arabinogalactan proteins in pollen tubes. All of the above results provide new insights into the regulatory role of boron in pollen tube development. In summary, boron likely plays a structural and regulatory role in relation to [Ca2+]c, actin cytoskeleton and cell wall components and thus regulates Malus domestica pollen germination and tube polar growth. PMID:26955377

  16. [Microplate luminometry for toxicity bioassay of chemicals on luciferase].

    PubMed

    Ge, Hui-Lin; Liu, Shu-Shen; Chen, Fu; Luo, Jin-Hui; Lü, Dai-Zhu; Su, Bing-Xia

    2013-10-01

    A new microplate luminometry for the toxicity bioassay of chemicals on firefly luciferase, was developed using the multifunctional microplate reader (SpectraMax M5) to measure the luminous intensity of luciferase. Efects of luciferase concentration, luciferin concentration, ATP concentration, pH, temperature, and reaction time on the luminescence were systematically investigated. It was found that ATP exerted a biphasic response on the luciferase luminescence and the maximum relative light units (RLU) occurred at an ATP concentration of 1.1 x 10(-4) mol x L(-1). The method was successfully employed in the toxic effect test of NaF, NaCl, KBr and NaBF4 on luciferase. Using nonlinear least square technique, the dose-response curves (DRC) of the 4 chemicals were accurately fitted with the coefficient of determination (R2) between the fitted and observed responses being greater than 0.99. The median effective concentration (EC50) of the 4 chemicals were accurately measured from the DRC models. Compared with some literatures, the bioassay is a fast easy-operate and cost-effective method with high accuracy.

  17. Cobalt toxicity in humans-A review of the potential sources and systemic health effects.

    PubMed

    Leyssens, Laura; Vinck, Bart; Van Der Straeten, Catherine; Wuyts, Floris; Maes, Leen

    2017-07-15

    Cobalt (Co) and its compounds are widely distributed in nature and are part of numerous anthropogenic activities. Although cobalt has a biologically necessary role as metal constituent of vitamin B 12 , excessive exposure has been shown to induce various adverse health effects. This review provides an extended overview of the possible Co sources and related intake routes, the detection and quantification methods for Co intake and the interpretation thereof, and the reported health effects. The Co sources were allocated to four exposure settings: occupational, environmental, dietary and medical exposure. Oral intake of Co supplements and internal exposure through metal-on-metal (MoM) hip implants deliver the highest systemic Co concentrations. The systemic health effects are characterized by a complex clinical syndrome, mainly including neurological (e.g. hearing and visual impairment), cardiovascular and endocrine deficits. Recently, a biokinetic model has been proposed to characterize the dose-response relationship and effects of chronic exposure. According to the model, health effects are unlikely to occur at blood Co concentrations under 300μg/l (100μg/l respecting a safety factor of 3) in healthy individuals, hematological and endocrine dysfunctions are the primary health endpoints, and chronic exposure to acceptable doses is not expected to pose considerable health hazards. However, toxic reactions at lower doses have been described in several cases of malfunctioning MoM hip implants, which may be explained by certain underlying pathologies that increase the individual susceptibility for Co-induced systemic toxicity. This may be associated with a decrease in Co bound to serum proteins and an increase in free ionic Co 2+ . As the latter is believed to be the primary toxic form, monitoring of the free fraction of Co 2+ might be advisable for future risk assessment. Furthermore, future research should focus on longitudinal studies in the clinical setting of Mo

  18. Retail lighting and packaging influence consumer acceptance of fluid milk.

    PubMed

    Potts, H L; Amin, K N; Duncan, S E

    2017-01-01

    Little is known about the effect of retail light-emitting diode (LED) exposure on consumer acceptance of milk. The study objective was to determine effects of fluorescent and LED lighting under retail storage conditions on consumer acceptance of milk. Consumer acceptance of milk stored under retail conditions was determined through sensory evaluation (2 studies; n=150+ each) and analytical measures (dissolved oxygen, secondary oxidation products, riboflavin retention). Study 1 evaluated milk stored in high-density polyethylene (HDPE) packages for 4h under LED light (960 lx). Commercially available HDPE package treatments included translucent HDPE (most commonly used), white HDPE [low concentration (1.3%) TiO 2 ], and yellow HDPE; in addition, HDPE with a higher TiO 2 concentration (high white; 4.9% TiO 2 ) and a foil-wrapped translucent HDPE (control) were tested. Translucent and control packages also were tested under fluorescent light. Study 2 evaluated polyethylene terephthalate (PET) packages for 4h under fluorescent and LED light (1,460 lx). The PET packaging included 2 treatments (medium, 4.0% TiO 2 ; high, 6.6% TiO 2 ) as well as translucent HDPE (exposed to fluorescent), clear PET (fluorescent and LED), and light-protected control. Overall mean acceptability of milk ranged from "like slightly" to "like moderately" with significantly lower acceptability for milk exposed to fluorescent light. Milk in HDPE and PET packages had comparable overall acceptability scores when exposed to LED light. Only the fluorescent light condition (both PET and HDPE) diminished overall acceptability. Fluorescent light exposure negatively influenced flavor with significant penalty (2.0-2.5 integers) to overall acceptability of milk in translucent HDPE and clear PET. The LED also diminished aftertaste of milk packaged in translucent HDPE. Changes in dissolved oxygen content, as an indication of oxidation, supported the observed differences in consumer acceptance of milk stored

  19. Evaluation of Metal Toxicity in Streams Affected by Abandoned Mine Lands, Upper Animas River Watershed, Colorado

    USGS Publications Warehouse

    Besser, John M.; Allert, Ann L.; Hardesty, Douglas K.; Ingersoll, Christopher G.; May, Thomas W.; Wang, Ning; Leib, Kenneth J.

    2001-01-01

    Acid drainage from abandoned mines and from naturally-acidic rocks and soil in the upper Animas River watershed of Colorado generates elevated concentrations of acidity and dissolved metals in stream waters and deposition of metal-contaminated particulates in streambed sediments, resulting in both toxicity and habitat degradation for stream biota. High concentrations of iron (Fe), aluminum (Al), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) occur in acid streams draining headwaters of the upper Animas River watershed, and high concentrations of some metals, especially Zn, persist in circumneutral reaches of the Animas River and Mineral Creek, downstream of mixing zones of acid tributaries. Seasonal variation of metal concentrations is reflected in variation in toxicity of stream water. Loadings of dissolved metals to the upper Animas River and tributaries are greatest during summer, during periods of high stream discharge from snowmelt and monsoonal rains, but adverse effects on stream biota may be greater during winter low-flow periods, when stream flows are dominated by inputs of groundwater and contain greatest concentrations of dissolved metals. Fine stream-bed sediments of the upper Animas River watershed also contain elevated concentrations of potentially toxic metals. Greatest sediment metal concentrations occur in the Animas River upstream from Silverton, where there are extensive deposits of mine and mill tailings, and in mixing zones in the Animas River and lower Mineral Creek, where precipitates of Fe and Al oxides also contain high concentrations of other metals. This report summarizes the findings of a series of toxicity studies in streams of the upper Animas River watershed, conducted on-site and in the laboratory between 1998 and 2000. The objectives of these studies were: (1) to determine the relative toxicity of stream water and fine stream-bed sediments to fish and invertebrates; (2) to determine the seasonal range of toxicity in stream

  20. Evaluation and optimization of the optical performance of low-concentrating dielectric compound parabolic concentrator using ray-tracing methods.

    PubMed

    Sarmah, Nabin; Richards, Bryce S; Mallick, Tapas K

    2011-07-01

    We present a detailed design concept and optical performance evaluation of stationary dielectric asymmetric compound parabolic concentrators (DiACPCs) using ray-tracing methods. Three DiACPC designs, DiACPC-55, DiACPC-66, and DiACPC-77, of acceptance half-angles (0° and 55°), (0° and 66°), and (0° and 77°), respectively, are designed in order to optimize the concentrator for building façade photovoltaic applications in northern latitudes (>55 °N). The dielectric concentrator profiles have been realized via truncation of the complete compound parabolic concentrator profiles to achieve a geometric concentration ratio of 2.82. Ray-tracing simulation results show that all rays entering the designed concentrators within the acceptance half-angle range can be collected without escaping from the parabolic sides and aperture. The maximum optical efficiency of the designed concentrators is found to be 83%, which tends to decrease with the increase in incidence angle. The intensity is found to be distributed at the receiver (solar cell) area in an inhomogeneous pattern for a wide range of incident angles of direct solar irradiance with high-intensity peaks at certain points of the receiver. However, peaks become more intense for the irradiation incident close to the extreme acceptance angles, shifting the peaks to the edge of the receiver. Energy flux distribution at the receiver for diffuse radiation is found to be homogeneous within ±12% with an average intensity of 520 W/m².

  1. Impact of non-constant concentration exposure on lethality of inhaled hydrogen cyanide.

    PubMed

    Sweeney, Lisa M; Sommerville, Douglas R; Channel, Stephen R

    2014-03-01

    The ten Berge model, also known as the toxic load model, is an empirical approach in hazard assessment modeling for estimating the relationship between the inhalation toxicity of a chemical and the exposure duration. The toxic load (TL) is normally expressed as a function of vapor concentration (C) and duration (t), with TL equaling C(n) × t being a typical form. Hypothetically, any combination of concentration and time that yields the same "toxic load" will give a constant biological response. These formulas have been developed and tested using controlled, constant concentration animal studies, but the validity of applying these assumptions to time-varying concentration profiles has not been tested. Experiments were designed to test the validity of the model under conditions of non-constant acute exposure. Male Sprague-Dawley rats inhaled constant or pulsed concentrations of hydrogen cyanide (HCN) generated in a nose-only exposure system for 5, 15, or 30 min. The observed lethality of HCN for the 11 different C versus t profiles was used to evaluate the ability of the model to adequately describe the lethality of HCN under the conditions of non-constant inhalation exposure. The model was found to be applicable under the tested conditions, with the exception of the median lethality of very brief, high concentration, discontinuous exposures.

  2. A toxicity-based method for evaluating safety of reclaimed water for environmental reuses.

    PubMed

    Xu, Jianying; Zhao, Chuntao; Wei, Dongbin; Du, Yuguo

    2014-10-01

    A large quantity of toxic chemical pollutants possibly remains in reclaimed water due to the limited removal efficiency in traditional reclamation processes. It is not enough to guarantee the safety of reclaimed water using conventional water quality criteria. An integrated assessment method based on toxicity test is necessary to vividly depict the safety of reclaimed water for reuse. A toxicity test battery consisting of lethality, genotoxicity and endocrine disrupting effect was designed to screen the multiple biological effects of residual toxic chemicals in reclaimed water. The toxicity results of reclaimed water were converted into the equivalent concentrations of the corresponding positive reference substances (EQC). Simultaneously, the predicted no-effect concentration (PNEC) of each positive reference substance was obtained by analyzing the species sensitivity distribution (SSD) of toxicity data. An index "toxicity score" was proposed and valued as 1, 2, 3, or 4 depending on the ratio of the corresponding EQC to PNEC. For vividly ranking the safety of reclaimed water, an integrated assessment index "toxicity rank" was proposed, which was classified into A, B, C, or D rank with A being the safest. The proposed method was proved to be effective in evaluating reclaimed water samples in case studies. Copyright © 2014. Published by Elsevier B.V.

  3. Teratological Effects of a Panel of Sixty Water-Soluble Toxicants on Zebrafish Development

    PubMed Central

    Ali, Shaukat; Aalders, Jeffrey

    2014-01-01

    Abstract The zebrafish larva is a promising whole-animal model for safety pharmacology, environmental risk assessment, and developmental toxicity. This model has been used for the high-throughput toxicity screening of various compounds. Our aim here is to identify possible phenotypic markers of teratogenicity in zebrafish embryos that could be used for the assaying compounds for reproductive toxicity. We have screened a panel of 60 water-soluble toxicants to examine their effects on zebrafish development. A total of 22,080 wild-type zebrafish larvae were raised in 250 μL defined buffer in 96-well plates at a plating density of one embryo per well. They were exposed for a 96-h period starting at 24 h post-fertilization. A logarithmic concentration series was used for range-finding, followed by a narrower geometric series for developmental toxicity assessment. A total of 9017 survivors were analyzed at 5 days post-fertilization for nine phenotypes, namely, (1) normal, (2) pericardial oedema, (3) yolk sac oedema, (4) melanophores dispersed, (5) bent tail tip, (6) bent body axis, (7) abnormal Meckel's cartilage, (8) abnormal branchial arches, and (9) uninflated swim bladder. For each toxicant, the EC50 (concentration required to produce one or more of these abnormalities in 50% of embryos) was also calculated. For the majority of toxicants (55/60) there was, at the population level, a statistically significant, concentration-dependent increase in the incidence of abnormal phenotypes among survivors. The commonest abnormalities were pericardial oedema, yolk sac oedema, dispersed melanophores, and uninflated swim bladder. It is possible therefore that these could prove to be general indicators of reproductive toxicity in the zebrafish embryo assay. PMID:24650241

  4. Methylglyoxal alleviates cadmium toxicity in wheat (Triticum aestivum L).

    PubMed

    Li, Zhong-Guang; Duan, Xiang-Qiu; Xia, Yan-Mei; Wang, Yue; Zhou, Zhi-Hao; Min, Xiong

    2017-02-01

    Methylglyoxal alleviates cadmium toxicity in wheat (Triticum aestivum L) by improving plant growth. For a long time, the reactive α, β-carbonyl ketoaldehyde methylglyoxal (CH3COCHO; MG) has been regarded as merely a toxic metabolite in plants, but, now, emerging as a signal molecule in plants. In this study, cadmium (Cd) stress decreased plant height, root length, fresh weight (FW), and dry weight (DW) in a concentration-dependent manner, indicating that Cd had toxic effects on the growth of wheat seedlings. The toxic effects of Cd were alleviated by exogenously applied MG in a dosage dependent fashion, and 700 mM MG reached significant differences, but this alleviating effect was eliminated by the treatment with N-acetyl-L-cysteine (NAC, MG scavenger), suggesting that MG could mitigate Cd toxicity in wheat. This study reported for the first time that MG could alleviate Cd toxicity in wheat, uncovering a new possible physiological function for MG, and opening a novel line of research in plant stress biology.

  5. Photostability and toxicity of finasteride, diclofenac and naproxen under simulating sunlight exposure: evaluation of the toxicity trend and of the packaging photoprotection

    PubMed Central

    2013-01-01

    Background Drugs photostability plays two different opposite roles; a real advantage arises considering the longer expiration time of the drugs while the consequent persistence in the environment involves an obvious negative effect bound to their harmfulness. On this basis we tested the photostability and toxicity of three pharmaceutical active principles: Finasteride, Diclofenac and Naproxen. The pure active principles, as well as commercial drugs containing them, were considered; for the last, the protective effect of the packaging was also evaluated. Samples were irradiated according to the ICH Guidelines for photostability testing (The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use); a simulating sunlight source (a mercury-vapor lamp coupled to a tungsten filament one) was used to cover the wavelength range 300–2000 nm; Temperature, Relative Humidity, Irradiance and Illuminance were maintained constant during the photodegradation. The concentrations of the pharmaceutical active principles during the photodegradation were monitored by HPLC with UV/Vis detector. Toxicity tests were performed by means of an amperometric biosensor based on suspended yeast cells. Since the products obtained by the photodegradation process can result as toxic or more toxic than the original molecules, tests were performed first and after the photodegadation. Results After 90 hours of exposure the concentration resulted lowered by 42.9%, 88.4% and 91% for Finasteride, Naproxen and Diclofenac respectively. Toxicity of the pure active principles follows the same order of the photostability. After photodegradation a contribute of the reaction products was evidenced. Conclusions The simple and cheap analytical procedure here proposed, allowed to obtain not only data on photostability and toxicity of the pure active principles but, even if roughly, also useful information on the reactions kinetic and toxicity of the

  6. Anesthesia-related Carbon Monoxide Exposure: Toxicity and Potential Therapy

    PubMed Central

    Levy, Richard J.

    2016-01-01

    Exposure to carbon monoxide (CO) during general anesthesia can result from volatile anesthetic degradation by carbon dioxide absorbents as well as re-breathing of endogenously produced CO. Although adherence to the Anesthesia Patient Safety Foundation guidelines reduces the risk of CO poisoning, patients may still experience a sub-toxic CO exposure during low-flow anesthesia. The consequences of such exposures are relatively unknown. In contrast to the widely recognized toxicity of high CO concentrations, the biological activity of low concentration CO has recently been shown be cytoprotective. As such, low dose CO is being explored as a novel treatment for a variety of different diseases. Here we review the concept of anesthesia-related CO exposure, identify the sources of production, detail the mechanisms of overt CO toxicity, highlight the cellular effects of low dose CO, and discuss the potential therapeutic role for CO as a part of routine anesthetic management. PMID:27537758

  7. Co-Formulants in Glyphosate-Based Herbicides Disrupt Aromatase Activity in Human Cells below Toxic Levels

    PubMed Central

    Defarge, Nicolas; Takács, Eszter; Lozano, Verónica Laura; Mesnage, Robin; Spiroux de Vendômois, Joël; Séralini, Gilles-Eric; Székács, András

    2016-01-01

    Pesticide formulations contain declared active ingredients and co-formulants presented as inert and confidential compounds. We tested the endocrine disruption of co-formulants in six glyphosate-based herbicides (GBH), the most used pesticides worldwide. All co-formulants and formulations were comparably cytotoxic well below the agricultural dilution of 1% (18–2000 times for co-formulants, 8–141 times for formulations), and not the declared active ingredient glyphosate (G) alone. The endocrine-disrupting effects of all these compounds were measured on aromatase activity, a key enzyme in the balance of sex hormones, below the toxicity threshold. Aromatase activity was decreased both by the co-formulants alone (polyethoxylated tallow amine—POEA and alkyl polyglucoside—APG) and by the formulations, from concentrations 800 times lower than the agricultural dilutions; while G exerted an effect only at 1/3 of the agricultural dilution. It was demonstrated for the first time that endocrine disruption by GBH could not only be due to the declared active ingredient but also to co-formulants. These results could explain numerous in vivo results with GBHs not seen with G alone; moreover, they challenge the relevance of the acceptable daily intake (ADI) value for GBHs exposures, currently calculated from toxicity tests of the declared active ingredient alone. PMID:26927151

  8. Toxicity assessment of heavy metal mixtures by Lemna minor L.

    PubMed

    Horvat, Tea; Vidaković-Cifrek, Zeljka; Orescanin, Visnja; Tkalec, Mirta; Pevalek-Kozlina, Branka

    2007-10-01

    The discharge of untreated electroplating wastewaters directly into the environment is a certain source of heavy metals in surface waters. Even though heavy metal discharge is regulated by environmental laws many small-scale electroplating facilities do not apply adequate protective measures. Electroplating wastewaters contain large amounts of various heavy metals (the composition depending on the facility) and the pH value often bellow 2. Such pollution diminishes the biodiversity of aquatic ecosystems and also endangers human health. The aim of our study was to observe/measure the toxic effects induced by a mixture of seven heavy metals on a bioindicator species Lemna minor L. Since artificial laboratory metal mixtures cannot entirely predict behaviour of metal mixtures nor provide us with informations relating to the specific conditions in the realistic environment we have used an actual electroplating wastewater sample discharged from a small electroplating facility. In order to obtain three more samples with the same composition of heavy metals but at different concentrations, the original electroplating wastewater sample has undergone a purification process. The purification process used was developed by Orescanin et al. [Orescanin V, Mikelić L, Lulić S, Nad K, Rubcić M, Pavlović G. Purification of electroplating wastewaters utilizing waste by-product ferrous sulphate and wood fly ash. J Environ Sci Health A 2004; 39 (9): 2437-2446.] in order to remove the heavy metals and adjust the pH value to acceptable values for discharge into the environment. Studies involving plants and multielemental waters are very rare because of the difficulty in explaining interactions of the combined toxicities. Regardless of the complexity in interpretation, Lemna bioassay can be efficiently used to assess combined effects of multimetal samples. Such realistic samples should not be avoided because they can provide us with a wide range of information which can help explain

  9. Multivariate relationships between groundwater chemistry and toxicity in an urban aquifer.

    PubMed

    Dewhurst, Rachel E; Wells, N Claire; Crane, Mark; Callaghan, Amanda; Connon, Richard; Mather, John D

    2003-11-01

    Multivariate statistical methods were used to investigate the causes of toxicity and controls on groundwater chemistry from 274 boreholes in an urban area (London) of the United Kingdom. The groundwater was alkaline to neutral, and chemistry was dominated by calcium, sodium, and sulfate. Contaminants included fuels, solvents, and organic compounds derived from landfill material. The presence of organic material in the aquifer caused decreases in dissolved oxygen, sulfate and nitrate concentrations, and increases in ferrous iron and ammoniacal nitrogen concentrations. Pearson correlations between toxicity results and the concentration of individual analytes indicated that concentrations of ammoniacal nitrogen, dissolved oxygen, ferrous iron, and hydrocarbons were important where present. However, principal component and regression analysis suggested no significant correlation between toxicity and chemistry over the whole area. Multidimensional scaling was used to investigate differences in sites caused by historical use, landfill gas status, or position within the sample area. Significant differences were observed between sites with different historical land use and those with different gas status. Examination of the principal component matrix revealed that these differences are related to changes in the importance of reduced chemical species.

  10. Sequential assessment via daphnia and zebrafish for systematic toxicity screening of heterogeneous substances.

    PubMed

    Jang, Gun Hyuk; Park, Chang-Beom; Kang, Benedict J; Kim, Young Jun; Lee, Kwan Hyi

    2016-09-01

    Environment and organisms are persistently exposed by a mixture of various substances. However, the current evaluation method is mostly based on an individual substance's toxicity. A systematic toxicity evaluation of heterogeneous substances needs to be established. To demonstrate toxicity assessment of mixture, we chose a group of three typical ingredients in cosmetic sunscreen products that frequently enters ecosystems: benzophenone-3 (BP-3), ethylhexyl methoxycinnamate (EHMC), and titanium dioxide nanoparticle (TiO2 NP). We first determined a range of nominal toxic concentration of each ingredient or substance using Daphnia magna, and then for the subsequent organismal level phenotypic assessment, chose the wild-type zebrafish embryos. Any phenotype change, such as body deformation, led to further examinations on the specific organs of transgenic zebrafish embryos. Based on the systematic toxicity assessments of the heterogeneous substances, we offer a sequential environmental toxicity assessment protocol that starts off by utilizing Daphnia magna to determine a nominal concentration range of each substance and finishes by utilizing the zebrafish embryos to detect defects on the embryos caused by the heterogeneous substances. The protocol showed additive toxic effects of the mixtures. We propose a sequential environmental toxicity assessment protocol for the systematic toxicity screening of heterogeneous substances from Daphnia magna to zebrafish embryo in-vivo models. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects

    USGS Publications Warehouse

    Buchwalter, D.B.; Cain, D.J.; Clements, W.H.; Luoma, S.N.

    2007-01-01

    Aquatic insects often dominate lotic ecosystems, yet these organisms are under-represented in trace metal toxicity databases. Furthermore, toxicity data for aquatic insects do not appear to reflect their actual sensitivities to metals in nature, because the concentrations required to elicit toxicity in the laboratory are considerably higher than those found to impact insect communities in the field. New approaches are therefore needed to better understand how and why insects are differentially susceptible to metal exposures. Biodynamic modeling is a powerful tool for understanding interspecific differences in trace metal bioaccumulation. Because bioaccumulation alone does not necessarily correlate with toxicity, we combined biokinetic parameters associated with dissolved cadmium exposures with studies of the subcellular compartmentalization of accumulated Cd. This combination of physiological traits allowed us to make predictions of susceptibility differences to dissolved Cd in three aquatic insect taxa: Ephemerella excrucians, Rhithrogena morrisoni, and Rhyacophila sp. We compared these predictions with long-term field monitoring data and toxicity tests with closely related taxa: Ephemerella infrequens, Rhithrogena hageni, and Rhyacophila brunea. Kinetic parameters allowed us to estimate steady-state concentrations, the time required to reach steady state, and the concentrations of Cd projected to be in potentially toxic compartments for different species. Species-specific physiological traits identified using biodynamic models provided a means for better understanding why toxicity assays with insects have failed to provide meaningful estimates for metal concentrations that would be expected to be protective in nature. ?? 2007 American Chemical Society.

  12. Microbial stabilization and mass reduction of wastes containing radionuclides and toxic metals

    DOEpatents

    Francis, A.J.; Dodge, C.J.; Gillow, J.B.

    1991-09-10

    A process is provided to treat wastes containing radionuclides and toxic metals with Clostridium sp. BFGl to release a large fraction of the waste solids into solution and convert the radionuclides and toxic metals to a more concentrated and stable form with concurrent volume and mass reduction. The radionuclides and toxic metals being in a more stable form are available for recovery, recycling and disposal. 18 figures.

  13. Microbial stabilization and mass reduction of wastes containing radionuclides and toxic metals

    DOEpatents

    Francis, Arokiasamy J.; Dodge, Cleveland J.; Gillow, Jeffrey B.

    1991-01-01

    A process is provided to treat wastes containing radionuclides and toxic metals with Clostridium sp. BFGl to release a large fraction of the waste solids into solutin and convert the radionuclides and toxic metals to a more concentrated and stable form with concurrent volume and mass reduction. The radionuclides and toxic metals being in a more stable form are available for recovery, recycling and disposal.

  14. Development and evaluation of consensus-based sediment effect concentrations for polychlorinated biphenyls

    USGS Publications Warehouse

    MacDonald, Donald D.; Dipinto, Lisa M.; Field, Jay; Ingersoll, Christopher G.; Long, Edward R.; Swartz, Richard C.

    2000-01-01

    Sediment-quality guidelines (SQGs) have been published for polychlorinated biphenyls (PCBs) using both empirical and theoretical approaches. Empirically based guidelines have been developed using the screening-level concentration, effects range, effects level, and apparent effects threshold approaches. Theoretically based guidelines have been developed using the equilibrium-partitioning approach. Empirically-based guidelines were classified into three general categories, in accordance with their original narrative intents, and used to develop three consensus-based sediment effect concentrations (SECs) for total PCBs (tPCBs), including a threshold effect concentration, a midrange effect concentration, and an extreme effect concentration. Consensus-based SECs were derived because they estimate the central tendency of the published SQGs and, thus, reconcile the guidance values that have been derived using various approaches. Initially, consensus-based SECs for tPCBs were developed separately for freshwater sediments and for marine and estuarine sediments. Because the respective SECs were statistically similar, the underlying SQGs were subsequently merged and used to formulate more generally applicable SECs. The three consensus-based SECs were then evaluated for reliability using matching sediment chemistry and toxicity data from field studies, dose-response data from spiked-sediment toxicity tests, and SQGs derived from the equilibrium-partitioning approach. The results of this evaluation demonstrated that the consensus-based SECs can accurately predict both the presence and absence of toxicity in field-collected sediments. Importantly, the incidence of toxicity increases incrementally with increasing concentrations of tPCBs. Moreover, the consensus-based SECs are comparable to the chronic toxicity thresholds that have been estimated from dose-response data and equilibrium-partitioning models. Therefore, consensus-based SECs provide a unifying synthesis of existing

  15. [Chemicals toxic to the olfactory system. Analysis and description].

    PubMed

    Norès, J M; Biacabe, B; Bonfils, P

    2000-10-28

    AN IMPORTANT PROBLEM: Occupational exposure to chemical products can have toxic effects on the olfactory system. An important number of patients have experienced olfactory disorders subsequent to the development of the chemical industry and atmospheric pollution. EPIDEMIOLOGY DATA: Straightforward data are difficult to collect because several cofactors other than the toxic product are involved. Two lists of toxic products can be made. The first list includes products for which scientific data is available and the second products for which data is lacking. Olfactory tests also differ between authors and countries. TWO TYPES OF TOXICITY: Acute, accidental toxicity is evidenced by the lesions caused by inhalation of high-doses of strongly toxic agents. Chronic intoxication caused by lower concentrations of these inhaled agents does not produce a trigeminal reflex leading to a modified respiratory rate reducing the airborne aggression. APPROXIMATIONS: Clinical data describing the olfactory toxicity of certain industrial and chemical compounds are very significant but often cannot prove a cause and effect relationship. Data obtained with experimental models in rodents are difficult to extrapolate to humans.

  16. Acute photo-induced toxicity and toxicokinetics of single compounds and mixtures of polycyclic aromatic hydrocarbons in zebrafish.

    PubMed

    Willis, Alison M; Oris, James T

    2014-09-01

    The present study examined photo-induced toxicity and toxicokinetics for acute exposure to selected polycyclic aromatic hydrocarbons (PAHs) in zebrafish. Photo-enhanced toxicity from co-exposure to ultraviolet (UV) radiation and PAHs enhanced the toxicity and exhibited toxic effects at PAH concentrations orders of magnitude below effects observed in the absence of UV. Because environmental exposure to PAHs is usually in the form of complex mixtures, the present study examined the photo-induced toxicity of both single compounds and mixtures of PAHs. In a sensitive larval life stage of zebrafish, acute photo-induced median lethal concentrations (LC50s) were derived for 4 PAHs (anthracene, pyrene, carbazole, and phenanthrene) to examine the hypothesis that phototoxic (anthracene and pyrene) and nonphototoxic (carbazole and phenanthrene) pathways of mixtures could be predicted from single exposures. Anthracene and pyrene were phototoxic as predicted; however, carbazole exhibited moderate photo-induced toxicity and phenanthrene exhibited weak photo-induced toxicity. The toxicity of each chemical alone was used to compare the toxicity of mixtures in binary, tertiary, and quaternary combinations of these PAHs, and a predictive model for environmental mixtures was generated. The results indicated that the acute toxicity of PAH mixtures was additive in phototoxic scenarios, regardless of the magnitude of photo-enhancement. Based on PAH concentrations found in water and circumstances of high UV dose to aquatic systems, there exists potential risk of photo-induced toxicity to aquatic organisms. © 2014 SETAC.

  17. Persistence and dioxin-like toxicity of carbazole and chlorocarbazoles in soil.

    PubMed

    Mumbo, John; Henkelmann, Bernhard; Abdelaziz, Ahmed; Pfister, Gerd; Nguyen, Nghia; Schroll, Reiner; Munch, Jean Charles; Schramm, Karl-Werner

    2015-01-01

    Halogenated carbazoles have recently been detected in soil and water samples, but their environmental effects and fate are unknown. Eighty-four soil samples obtained from a site with no recorded history of pollution were used to assess the persistence and dioxin-like toxicity of carbazole and chlorocarbazoles in soil under controlled conditions for 15 months. Soil samples were divided into two temperature conditions, 15 and 20 °C, both under fluctuating soil moisture conditions comprising 19 and 44 drying-rewetting cycles, respectively. This was characterized by natural water loss by evaporation and rewetting to -15 kPa. Accelerated solvent extraction (ASE) and cleanup were performed after incubation. Identification and quantification were done using high-resolution gas chromatogram/mass spectrometer (HRGC/MS), while dioxin-like toxicity was determined by ethoxyresorufin-O-deethylase (EROD) induction in H4IIA rat hepatoma cells assay and multidimensional quantitative structure-activity relationships (mQSAR) modelling. Carbazole, 3-chlorocarbazole and 3,6-dichlorocarbazole were detected including trichlorocarbazole not previously reported in soils. Carbazole and 3-chlorocarbazole showed significant dissipation at 15 °C but not at 20 °C incubating conditions indicating that low temperature could be suitable for dissipation of carbazole and chlorocarbazoles. 3,6-Dichlorocarbazole was resistant at both conditions. Trichlorocarbazole however exhibited a tendency to increase in concentration with time. 3-Chlorocarbazole, 3,6-dibromocarbazole and selected soil extracts exhibited EROD activity. Dioxin-like toxicity did not decrease significantly with time, whereas the sum chlorocarbazole toxic equivalence concentrations (∑TEQ) did not contribute significantly to the soil assay dioxin-like toxicity equivalent concentrations (TCDD-EQ). Carbazole and chlorocarbazoles are persistent with the latter also toxic in natural conditions.

  18. [The toxicity variation of organic extracts in drinking water treatment processes].

    PubMed

    Mei, M; Wei, S; Zijian, W; Wenhua, W; Baohua, Z; Suxia, Z

    2001-01-01

    Source water samples and outlet water samples from different treatment processes of the Beijing Ninth Water Works were concentrated in situ with XAD-2 filled columns. GC-MS analysis and toxic assessment including acute toxicity evaluation by luminescent bacterium bioassay(Q67 strains) and mutagenicity assessment by Ames test(TA98 and TA100 strains with and without S9 addition) were conducted on these samples. The results showed that prechlorination caused the direct and indirect frame shift mutagenicity as well as indirect base pair substitute mutagenicity. Addition of coagulant may increase the base pair substitute mutagenic effects greatly. Sand and coal filtration and granular activated carbon filtration could effectively remove most of the formed mutagens. The rechlorination do not obviously increase the mutagenic effects. No mutagenic effect was observed in tap water. Acute toxicity showed the same variation with that of mutagenicity during the treatment processes. Sample from flocculation treatment process was found to be the most toxic sample. Results of GC-MS analysis showed that water in this plant was not contaminated by PCB. Concentrations of toluene, naphthalene and phenol increased in flocculation treatment process and in tap water. However, the concentrations of these substances were at the level of microgram/L, therefore, were not high enough to cause mutagenicity.

  19. Acceptance criteria for urban dispersion model evaluation

    NASA Astrophysics Data System (ADS)

    Hanna, Steven; Chang, Joseph

    2012-05-01

    The authors suggested acceptance criteria for rural dispersion models' performance measures in this journal in 2004. The current paper suggests modified values of acceptance criteria for urban applications and tests them with tracer data from four urban field experiments. For the arc-maximum concentrations, the fractional bias should have a magnitude <0.67 (i.e., the relative mean bias is less than a factor of 2); the normalized mean-square error should be <6 (i.e., the random scatter is less than about 2.4 times the mean); and the fraction of predictions that are within a factor of two of the observations (FAC2) should be >0.3. For all data paired in space, for which a threshold concentration must always be defined, the normalized absolute difference should be <0.50, when the threshold is three times the instrument's limit of quantification (LOQ). An overall criterion is then applied that the total set of acceptance criteria should be satisfied in at least half of the field experiments. These acceptance criteria are applied to evaluations of the US Department of Defense's Joint Effects Model (JEM) with tracer data from US urban field experiments in Salt Lake City (U2000), Oklahoma City (JU2003), and Manhattan (MSG05 and MID05). JEM includes the SCIPUFF dispersion model with the urban canopy option and the urban dispersion model (UDM) option. In each set of evaluations, three or four likely options are tested for meteorological inputs (e.g., a local building top wind speed, the closest National Weather Service airport observations, or outputs from numerical weather prediction models). It is found that, due to large natural variability in the urban data, there is not a large difference between the performance measures for the two model options and the three or four meteorological input options. The more detailed UDM and the state-of-the-art numerical weather models do provide a slight improvement over the other options. The proposed urban dispersion model acceptance

  20. Anaerobic Toxicity of Cationic Silver Nanoparticles | Science ...

    EPA Pesticide Factsheets

    The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag+ under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged polyvinylpyrrolidone coated AgNPs (PVP-AgNps) and (3) positively charged branched polyethyleneimine coated AgNPs (BPEI-AgNPs). The AgNPs investigated in this experiment were similar in size (10-15 nm), spherical in shape, but varied in surface charge which ranged from highly negative to highly positive. While, at AgNPs concentrations lower than 5 mg L-1, the anaerobic decomposition process was not influenced by the presence of the nanoparticles, there was an observed impact on the diversity of the microbial community. At elevated concentrations (100 mg L-1 as silver), only the cationic BPEI-AgNPs demonstrated toxicity similar in magnitude to that of Ag+. Both citrate and PVP-AgNPs did not exhibit toxicity at the 100 mg L-1 as measured by biogas evolution. These findings further indicate the varying modes of action for nanoparticle toxicity and represent one of the few studies that evaluate end-of-life management concerns with regards to the increasing use of nanomaterials in our everyday life. These findings also highlight some of the concerns with a one size fits all approach to the evaluation of environmental health and safety concerns associated with the use of nanoparticles. The current

  1. 6 CFR 27.204 - Minimum concentration by security issue.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Section 27.204 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY CHEMICAL FACILITY ANTI-TERRORISM STANDARDS Chemical Facility Security Program § 27.204 Minimum concentration by security issue. (a) Release Chemicals—(1) Release-Toxic Chemicals. If a release-toxic chemical of interest...

  2. Identifying the cause of sediment toxicity in agricultural sediments: the role of pyrethroids and nine seldom-measured hydrophobic pesticides.

    PubMed

    Weston, Donald P; Ding, Yuping; Zhang, Minghua; Lydy, Michael J

    2013-01-01

    Few currently used agricultural pesticides are routinely monitored for in the environment. Even if concentrations are known, sediment LC(50) values are often lacking for common sediment toxicity testing species. To help fill this data gap, sediments in California's Central Valley were tested for nine hydrophobic pesticides seldom analyzed: abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin. Most were detected, but rarely at concentrations acutely toxic to Hyalella azteca or Chironomus dilutus. Only abamectin, fenpropathrin, and methyl parathion were found at concentrations of potential concern, and only in one or two samples. One-quarter of over 100 samples from agriculture-affected waterways exhibited toxicity, and in three-fourths of the toxic samples, pyrethroids exceeded concentrations expected to cause toxicity. The pyrethroid Bi-fen-thrin in particular, as well as lambda-cyhalothrin, cypermethrin, esfenvalerate, permethrin, and the organophosphate chlorpyrifos, were primarily responsible for the observed toxicity, rather than the more novel analytes, despite the fact that much of the sampling targeted areas of greatest use of the novel pesticides. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Influence of in-stream diel concentration cycles of dissolved trace metals on acute toxicity to one-year-old cutthroat trout (Oncorhynchus clarki lewisi)

    USGS Publications Warehouse

    Nimick, D.A.; Harper, D.D.; Farag, A.M.; Cleasby, T.E.; MacConnell, Elizabeth; Skaar, D.

    2007-01-01

    Extrapolating results of laboratory bioassays to streams is difficult, because conditions such as temperature and dissolved metal concentrations can change substantially on diel time scales. Field bioassays conducted for 96 h in two mining-affected streams compared the survival of hatchery-raised, metal-nai??ve westslope cutthroat trout (Oncorhynchus clarki lewisi) exposed to dissolved (0.1-??m filtration) metal concentrations that either exhibited the diel variation observed in streams or were controlled at a constant value. Cadmium and Zn concentrations in these streams increased each night by as much as 61 and 125%, respectively, and decreased a corresponding amount the next day, whereas Cu did not display a diel concentration cycle. In High Ore Creek (40 km south of Helena, MT, USA), survival (33%) after exposure to natural diel-fluctuating Zn concentrations (range, 214-634 ??g/L; mean, 428 ??g/L) was significantly (p = 0.008) higher than survival (14%) after exposure to a controlled, constant Zn concentration (422 ??g/L). Similarly, in Dry Fork Belt Creek (70 km southeast of Great Falls, MT, USA), survival (75%) after exposure to diel-fluctuating Zn concentrations (range, 266-522 ??g/L; mean, 399 ??g/L) was significantly (p = 0.022) higher than survival (50%) in the constant-concentration treatment (392 ??g/L). Survival likely was greater in these diel treatments, both because the periods of lower metal concentrations provided some relief for the fish and because toxicity during periods of higher metal concentrations was lessened by the simultaneous occurrence each night of lower water temperatures, which reduce the rate of metal uptake. Based on the present study, current water-quality criteria appear to be protective for streams with diel concentration cycles of Zn (and, perhaps, Cd) for the hydrologie conditions tested. ?? 2007 SETAC.

  4. Comparison of the toxicity of fluoridation compounds in the nematode Caenorhabditis elegans.

    PubMed

    Rice, Julie R; Boyd, Windy A; Chandra, Dave; Smith, Marjolein V; Den Besten, Pamela K; Freedman, Jonathan H

    2014-01-01

    Fluorides are commonly added to drinking water in the United States to decrease the incidence of dental caries. Silicofluorides, such as sodium hexafluorosilicate (Na2 SiF6 ) and fluorosilicic acid (H2 SiF6 ), are mainly used for fluoridation, although fluoride salts such as sodium fluoride (NaF) are also used. Interestingly, only the toxicity of NaF has been examined and not that of the more often used silicofluorides. In the present study, the toxicities of NaF, Na2 SiF6 , and H2 SiF6 were compared. The toxicity of these fluorides on the growth, feeding, and reproduction in the alternative toxicological testing organism Caenorhabditis elegans was examined. Exposure to these compounds produced classic concentration-response toxicity profiles. Although the effects of the fluoride compounds varied among the 3 biological endpoints, no differences were found between the 3 compounds, relative to the fluoride ion concentration, in any of the assays. This suggests that silicofluorides have similar toxicity to NaF. © 2013 SETAC.

  5. Improving Toxicity Assessment of Pesticide Mixtures: The Use of Polar Passive Sampling Devices Extracts in Microalgae Toxicity Tests

    PubMed Central

    Kim Tiam, Sandra; Fauvelle, Vincent; Morin, Soizic; Mazzella, Nicolas

    2016-01-01

    Complexity of contaminants exposure needs to be taking in account for an appropriate evaluation of risks related to mixtures of pesticides released in the ecosystems. Toxicity assessment of such mixtures can be made through a variety of toxicity tests reflecting different level of biological complexity. This paper reviews the recent developments of passive sampling techniques for polar compounds, especially Polar Organic Chemical Integrative Samplers (POCIS) and Chemcatcher® and the principal assessment techniques using microalgae in laboratory experiments. The progresses permitted by the coupled use of such passive samplers and ecotoxicology testing as well as their limitations are presented. Case studies combining passive sampling devices (PSD) extracts and toxicity assessment toward microorganisms at different biological scales from single organisms to communities level are presented. These case studies, respectively, aimed (i) at characterizing the “toxic potential” of waters using dose-response curves, and (ii) at performing microcosm experiments with increased environmental realism in the toxicant exposure in term of cocktail composition and concentration. Finally perspectives and limitations of such approaches for future applications in the area of environmental risk assessment are discussed. PMID:27667986

  6. Acute toxicity of fire control chemicals to Daphnia magna(Straus) and Selenastrum capricornutum(Printz)

    USGS Publications Warehouse

    McDonald, Susan F.; Hamilton, Steven J.; Buhl, Kevin J.; Heisinger, James F.

    1996-01-01

    Acute toxicity tests were conducted exposingDaphnia magnaStraus (daphnid) in soft and hard reconstituted waters (hardness 42 and 162 mg/liter as CaCO3, respectively), andSelenastrum capricornutumPrintz (algae) in ASTM algal assay medium (hardness 15 mg/liter as CaCO3) to fire retardants Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F, and foam suppressants Phos-Chek WD-881 and Silv-Ex. The chemicals were slightly toxic to practically harmless to daphnids and moderately toxic to algae. Water quality did not consistently alter the toxicity of the test chemicals to daphnids. The most toxic chemical to daphnids was Silv-Ex (48-hr EC507 mg/liter in soft and hard waters), whereas the least toxic chemical to daphnids was Fire-Trol LCG-R (48-hr EC50848 mg/liter in soft water, 813 mg/liter in hard water). The most toxic chemical to algae was Fire-Trol LCG-R (96-hr IC5010 mg/liter), and the least toxic chemical was Phos-Chek D75-F (96-hr IC5079 mg/liter). Un-ionized ammonia concentrations near the EC50or IC50value in tests with the Fire-Trol compounds were frequently equal to or above reported LC50un-ionized ammonia concentrations. Un-ionized ammonia concentrations in tests with Phos-Chek D75-F were low, thus other toxic components present in the compounds probably contributed to the toxicity. When compared to the daphnids tested in ASTM soft water, the Fire-Trol compounds were most toxic to algae, whereas Phos-Chek D75-F and the foam suppressants were most toxic to daphnids. The results of these tests are comparable to those obtained from research conducted in other laboratories with the same species and similar chemicals. Accidental entry of fire-fighting chemicals into aquatic environments could adversely affect algae and aquatic invertebrates, thus disrupting ecosystem function.

  7. PHOTOACTIVATION AND TOXICITY OF MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN MARINE SEDIMENT

    EPA Science Inventory

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration se...

  8. A high throughput passive dosing format for the Fish Embryo Acute Toxicity test.

    PubMed

    Vergauwen, Lucia; Schmidt, Stine N; Stinckens, Evelyn; Maho, Walid; Blust, Ronny; Mayer, Philipp; Covaci, Adrian; Knapen, Dries

    2015-11-01

    High throughput testing according to the Fish Embryo Acute Toxicity (FET) test (OECD Testing Guideline 236) is usually conducted in well plates. In the case of hydrophobic test substances, sorptive and evaporative losses often result in declining and poorly controlled exposure conditions. Therefore, our objective was to improve exposure conditions in FET tests by evaluating a passive dosing format using silicone O-rings in standard 24-well polystyrene plates. We exposed zebrafish embryos to a series of phenanthrene concentrations until 120h post fertilization (hpf), and obtained a linear dilution series. We report effect values for both mortality and sublethal morphological effects based on (1) measured exposure concentrations, (2) (lipid normalized) body residues and (3) chemical activity. The LC50 for 120hpf was 310μg/L, CBR50 (critical body residue) was 2.72mmol/kg fresh wt and La50 (lethal chemical activity) was 0.047. All values were within ranges expected for baseline toxicity. Impaired swim bladder inflation was the most pronounced morphological effect and swimming activity was reduced in all exposure concentrations. Further analysis showed that the effect on swimming activity was not attributed to impaired swim bladder inflation, but rather to baseline toxicity. We conclude that silicone O-rings (1) produce a linear dilution series of phenanthrene in the 120hpf FET test, (2) generate and maintain aqueous concentrations for reliable determination of effect concentrations, and allow for obtaining mechanistic toxicity information, and (3) cause no toxicity, demonstrating its potential as an extension of the FET test when testing hydrophobic chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Copper bioavailability and toxicity to Mytilus galloprovincialis in Shelter Island Yacht Basin, San Diego, CA.

    PubMed

    Bosse, Casey; Rosen, Gunther; Colvin, Marienne; Earley, Patrick; Santore, Robert; Rivera-Duarte, Ignacio

    2014-08-15

    The bioavailability and toxicity of copper (Cu) in Shelter Island Yacht Basin (SIYB), San Diego, CA, USA, was assessed with simultaneous toxicological, chemical, and modeling approaches. Toxicological measurements included laboratory toxicity testing with Mytilus galloprovincialis (Mediterranean mussel) embryos added to both site water (ambient) and site water spiked with multiple Cu concentrations. Chemical assessment of ambient samples included total and dissolved Cu concentrations, and Cu complexation capacity measurements. Modeling was based on chemical speciation and predictions of bioavailability and toxicity using a marine Biotic Ligand Model (BLM). Cumulatively, these methods assessed the natural buffering capacity of Cu in SIYB during singular wet and dry season sampling events. Overall, the three approaches suggested negligible bioavailability, and isolated observed or predicted toxicity, despite an observed gradient of increasing Cu concentration, both horizontally and vertically within the water body, exceeding current water quality criteria for saltwater. Published by Elsevier Ltd.

  10. National review of ambient air toxics observations.

    PubMed

    Strum, Madeleine; Scheffe, Richard

    2016-02-01

    Ambient air observations of hazardous air pollutant (HAPs), also known as air toxics, derived from routine monitoring networks operated by states, local agencies, and tribes (SLTs), are analyzed to characterize national concentrations and risk across the nation for a representative subset of the 187 designated HAPs. Observations from the National Air Toxics Trend Sites (NATTS) network of 27 stations located in most major urban areas of the contiguous United States have provided a consistent record of HAPs that have been identified as posing the greatest risk since 2003 and have also captured similar concentration patterns of nearly 300 sites operated by SLTs. Relatively high concentration volatile organic compounds (VOCs) such as benzene, formaldehyde, and toluene exhibit the highest annual average concentration levels, typically ranging from 1 to 5 µg/m(3). Halogenated (except for methylene chloride) and semivolatile organic compounds (SVOCs) and metals exhibit concentrations typically 2-3 orders of magnitude lower. Formaldehyde is the highest national risk driver based on estimated cancer risk and, nationally, has not exhibited significant changes in concentration, likely associated with the large pool of natural isoprene and formaldehyde emissions. Benzene, toluene, ethylbenzene, and 1,3-butadiene are ubiquitous VOC HAPs with large mobile source contributions that continue to exhibit declining concentrations over the last decade. Common chlorinated organic compounds such as ethylene dichloride and methylene chloride exhibit increasing concentrations. The variety of physical and chemical attributes and measurement technologies across 187 HAPs result in a broad range of method detection limits (MDLs) and cancer risk thresholds that challenge confidence in risk results for low concentration HAPs with MDLs near or greater than risk thresholds. From a national monitoring network perspective, the ability of the HAPs observational database to characterize the multiple

  11. Biological and chemical analysis of the toxic potency of pesticides in rainwater.

    PubMed

    Hamers, T; Smit, M G; Murk, A J; Koeman, J H

    2001-11-01

    A newly developed method for measuring the integrated esterase inhibiting potency of rainwater samples was applied in practice, and the results are compared to the toxic potency calculated from concentrations of 31 organophosphate (OP) and carbamate pesticides, out of a total of 66 chemically analyzed pesticides. In addition, the general toxic potency of the rainwater samples was evaluated in a microtiter luminescence assay with Vibrio fischeri bacteria. Rainwater samples were collected over four consecutive 14-day periods in both open and wet-only samplers. The esterase inhibiting potency of the open rainwater samples (expressed as ng dichlorvos-equivalents/l) corresponded well with the chemical analyses of the rainwater samples collected by both types of samplers (r = 0.83-0.86). By far, the highest esterase inhibiting potency was found in a sample collected in an area with intense horticultural activities in June, and was attributed to high concentrations of dichlorvos, mevinphos, pirimiphos-methyl and methiocarb. The esterase inhibiting potency of this sample was equivalent to a dichlorvos concentration of 1380 ng/l in the rainwater, which is almost 2000 times higher than the maximum permissible concentration (MPC) of dichlorvos set for surface water in Netherlands. Maximum individual concentrations of dichlorvos and pirimiphos-methyl even exceeded the EC50 for Daphnia, suggesting that pesticides in rainwater pose a risk for aquatic organisms. Not all responses of the luminescence-assay for general toxicity could be explained by the analyzed pesticide concentrations. The bio-assays enable a direct assessment the toxic potency of all individual compounds present in the complex mixture of rainwater pollutants, even if they are unknown or present at concentrations below the detection limit. Therefore, they are valuable tools for prescreening and hazard characterization purposes.

  12. Toxicity of municipal wastewater effluents contaminated by pentachlorophenol in southwest Missouri

    USGS Publications Warehouse

    Wylie, G.D.; Finger, S.E.; Crawford, R.W.

    1990-01-01

    Toxicity of effluents from two sewage treatment plants in Joplin, Missouri, was tested using Ceriodaphnia dubia and Pimephales promelas. No test organisms survived in effluents from either plant, in effluents diluted with water from Turkey Creek (the receiving stream), or in water from Turkey Creek. Mortality was complete in all but the most dilute treatments of effluents, in which reconstituted water was used as the diluent. High concentrations of pentachlorophenol (130–970 μg liter−1) in effluents and the receiving stream likely caused mortality during the 7-day tests. Detectable concentrations of other phenolic compounds indicated the presence in Turkey Creek of other toxic by-products of pentachlorophenol manufacture. This study demonstrated the utility of biological tests of whole effluents to determine toxicity of wastewater effluents.

  13. Toxicity of Diclofenac in the Fern Azolla filiculoides and the Lichen Xanthoria parietina.

    PubMed

    Vannini, Andrea; Paoli, Luca; Vichi, Marco; Bačkor, Martin; Bačkorová, Miriam; Loppi, Stefano

    2018-03-01

    This study investigated the occurrence of toxicity, expressed as damage to the photosynthetic apparatus, in the aquatic fern Azolla filiculoides and the lichen Xanthoria parietina following treatments with diclofenac at different concentrations (0.1, 1, 10 and 100 mg/L) and different exposure times (24, 48, 72 and 240 h). Measurements of photosynthetic efficiency, chlorophyll content and chlorophyll degradation indicated dose- and time-dependent toxicity, since significant differences with control samples as well as among treatments, emerged mainly for the highest concentration (100 mg/L) and the longest time (240 h). In addition, also the mycobiont of the lichen X. parietina showed similar toxic effects, expressed as ergosterol content. The absence of relevant alterations at the lowest concentration (0.1 mg/L) suggested a very limited susceptibility of these species to environmentally relevant levels of this pharmaceutical.

  14. Assessment and prediction of joint algal toxicity of binary mixtures of graphene and ionic liquids.

    PubMed

    Wang, Zhuang; Zhang, Fan; Wang, Se; Peijnenburg, Willie J G M

    2017-10-01

    Graphene and ionic liquids (ILs) released into the environment will interact with each other. So far however, the risks associated with the concurrent exposure of biota to graphene and ILs in the environment have received little attention. The research reported here focused on observing and predicting the joint toxicity effects in the green alga Scenedesmus obliquus exposed to binary mixtures of intrinsic graphene (iG)/graphene oxide (GO) and five ILs of varying anionic and cationic types. The isolated ILs in the binary mixtures were the main contributors to toxicity. The binary GO-IL mixtures resulted in more severe joint toxicity than the binary iG-IL mixtures, irrespective of mixture ratios. The mechanism of the joint toxicity may be associated with the adsorption capability of the graphenes for the ILs, the dispersion stability of the graphenes in aquatic media, and modulation of the binary mixtures-induced oxidative stress. A toxic unit assessment showed that the graphene and IL toxicities were additive at low concentration of the mixtures but antagonistic at high concentration of the mixtures. Predictions made using the concentration addition and independent action models were close to the observed joint toxicities regardless of mixture types and mixture ratios. These findings provide new insights that are of use in the risk assessment of mixtures of engineered nanoparticles and other environmentally relevant contaminants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Toxicity of platinum, palladium and rhodium to Daphnia magna in single and binary metal exposure experiments.

    PubMed

    Zimmermann, Sonja; Wolff, Carolina; Sures, Bernd

    2017-05-01

    Mainly due to automobile traffic, but also due to other sources, the platinum group elements (PGE) platinum (Pt), palladium (Pd) and rhodium (Rh) are introduced into aquatic biotopes where they accumulate in sediments of lakes and rivers. However, the toxicity of these noble metals to aquatic organisms is not well understood and especially toxicity studies under standardized condition are lacking. Thus, the toxicity of Pt, Pd and Rh to Daphnia magna was tested in single metal exposure experiments according to OECD guideline 202. Immobility and lethality was recorded after 24 h and 48 h of exposure and EC 50 and LC 50 , respectively, were determined. As the nominal exposure concentration of Pd differed significantly from the quantified concentration, the control of the real exposure concentration by chemical analysis is mandatory, especially for Pd. The toxicity decreased in the order Pd > Pt ≫ Rh with e.g. LC 50 (48 h) values of 14 μg/L for Pd, 157 μg/L for Pt and 56,800 μg/L for Rh. The exposure period had a clear effect on the toxicity of Pt, Pd and Rh. For Pt and Rh the endpoint immobility was more sensitive than the endpoint lethality whereas Pd toxicity was similar for both endpoints. The Hill slopes, which are a measure for the steepness of the concentration-response curves, showed no significant discrepancies between the different metals. The binary metal exposure to Pt and Pd revealed a more-than-additive, i.e. a synergistic toxicity using the toxic unit approach. The present study is a start to understand the toxicity of interacting PGE. The modes of action behind the synergistic effect are unclear. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The influence of particles on bioavailability and toxicity of pesticides in surface water.

    PubMed

    Knauer, Katja; Homazava, Nadzeya; Junghans, Marion; Werner, Inge

    2017-07-01

    Environmental risk assessment is an essential part of the approval process for pesticides. Exposure concentrations are compared with ecotoxicological data obtained from standardized laboratory studies and, if available, from field studies to determine the risk of a substance or formulation for aquatic communities. Predicted concentrations in surface waters are derived using, for example, the European FOrum for the Co-ordination of pesticide fate models and their USe (FOCUS) or the German Exposit models, which distinguish between exposure to dissolved and particle-associated pesticide concentrations, because the dissolved concentration is thought to be the best predictor of bioavailability and toxicity. Water and particle-associated concentrations are estimated based on the organic carbon-water partitioning coefficient (K OC ). This review summarizes published information on the influence of natural suspended solids on bioavailability and toxicity of pesticides to aquatic organisms (algae, invertebrates and fish), and the value of log K OC and log K OW (octanol-water coefficient) as sole predictors of the bioavailable fraction is discussed. The information showed that: 1) the quality and origin of suspended solids played an important role in influencing pesticide bioavailability and toxicity; 2) a decrease in toxicity due to the presence of suspended solids was shown only for pyrethroid insecticides with log K OW greater than 5, but the extent of this reduction depended on particle concentration and size, and potentially also on the ecotoxicological endpoint; 3) for pesticides with a log K OW less than 3 (e.g., triazines, carbamates, and organophosphates), the impact of particles on bioavailability and toxicity is small and species dependent; and 4) pesticide bioavailability is greatly influenced by the test species and their physiology (e.g., feeding behavior or digestion). We conclude that exposure of aquatic organisms to pesticides and environmental risk of many

  17. Temporal variability of selected air toxics in the United States

    NASA Astrophysics Data System (ADS)

    McCarthy, Michael C.; Hafner, Hilary R.; Chinkin, Lyle R.; Charrier, Jessica G.

    Ambient measurements of hazardous air pollutants (HAPs, air toxics) collected in the United States from 1990 to 2005 were analyzed for diurnal, seasonal, and/or annual variability and trends. Visual and statistical analyses were used to identify and quantify temporal variations in air toxics at national and regional levels. Sufficient data were available to analyze diurnal variability for 14 air toxics, seasonal variability for 24 air toxics, and annual trends for 26 air toxics. Four diurnal variation patterns were identified and labeled invariant, nighttime peak, morning peak, and daytime peak. Three distinct seasonal patterns were identified and labeled invariant, cool, and warm. Multiple air toxics showed consistent decreasing trends over three trend periods, 1990-2005, 1995-2005, and 2000-2005. Trends appeared to be relatively consistent within chemically similar pollutant groups. Hydrocarbons such as benzene, 1,3-butadiene, styrene, xylene, and toluene decreased by approximately 5% or more per year at more than half of all monitoring sites. Concentrations of carbonyl compounds such as formaldehyde, acetaldehyde, and propionaldehyde were equally likely to have increased or decreased at monitoring sites. Chlorinated volatile organic compounds (VOCs) such as tetrachloroethylene, dichloromethane, and methyl chloroform decreased at more than half of all monitoring sites, but decreases among these species were much more variable than among the hydrocarbons. Lead particles decreased in concentration at most monitoring sites, but trends in other metals were not consistent over time.

  18. Demonstration of a Non-Toxic Reaction Control Engine

    NASA Technical Reports Server (NTRS)

    Robinson, Philip J.; Veith, Eric M.; Turpin, Alicia A.

    2006-01-01

    Three non-toxic demonstration reaction control engines (RCE) were successfully tested at the Aerojet Sacramento facility under a technology contract sponsored by the National Aeronautics and Space Administration s (NASA) Marshall Space Flight Center (MSFC). The goals of the NASA MSFC contract (NAS8-01109) were to develop and expand the technical maturity of a non-toxic, on-orbit auxiliary propulsion system (APS) thruster under the auspices of the Exploration Systems Mission Directorate. The demonstration engine utilized Liquid Oxygen (LOX) and Ethanol as propellants to produce 870 lbf thrust. The Aerojet RCE s were successfully acceptance tested over a broad range of operating conditions. Steady state tests evaluated engine response to varying chamber pressures and mixture ratios. In addition to the steady state tests, a variety of pulsing tests were conducted over a wide range of electrical pulse widths (EPW). Each EPW condition was also tested over a range of percent duty cycles (DC), and bit impulse and pulsing specific impulse were determined for each of these conditions. White Sands Test Facility (WSTF) in April 2005 for incorporation into a cryogenic Auxiliary Propulsion System Test Bed (APSTB). The APSTB is a test article that will be utilized in an altitude test cell to simulate anticipated mission applications. The objectives of this APSTB testing included evaluation of engine performance over an extended duty cycle map of propellant pressure and temperature, as well as engine and system performance at typical mission duty cycles over extended periods of time. This paper provides acceptance test results and a status of the engine performance as part of the system level testing. Subsequent to acceptance testing at Aerojet, these three engines were delivered to the NASA

  19. A hypothetical model for predicting the toxicity of high aspect ratio nanoparticles (HARN)

    NASA Astrophysics Data System (ADS)

    Tran, C. L.; Tantra, R.; Donaldson, K.; Stone, V.; Hankin, S. M.; Ross, B.; Aitken, R. J.; Jones, A. D.

    2011-12-01

    The ability to predict nanoparticle (dimensional structures which are less than 100 nm in size) toxicity through the use of a suitable model is an important goal if nanoparticles are to be regulated in terms of exposures and toxicological effects. Recently, a model to predict toxicity of nanoparticles with high aspect ratio has been put forward by a consortium of scientists. The High aspect ratio nanoparticles (HARN) model is a platform that relates the physical dimensions of HARN (specifically length and diameter ratio) and biopersistence to their toxicity in biological environments. Potentially, this model is of great public health and economic importance, as it can be used as a tool to not only predict toxicological activity but can be used to classify the toxicity of various fibrous nanoparticles, without the need to carry out time-consuming and expensive toxicology studies. However, this model of toxicity is currently hypothetical in nature and is based solely on drawing similarities in its dimensional geometry with that of asbestos and synthetic vitreous fibres. The aim of this review is two-fold: (a) to present findings from past literature, on the physicochemical property and pathogenicity bioassay testing of HARN (b) to identify some of the challenges and future research steps crucial before the HARN model can be accepted as a predictive model. By presenting what has been done, we are able to identify scientific challenges and research directions that are needed for the HARN model to gain public acceptance. Our recommendations for future research includes the need to: (a) accurately link physicochemical data with corresponding pathogenicity assay data, through the use of suitable reference standards and standardised protocols, (b) develop better tools/techniques for physicochemical characterisation, (c) to develop better ways of monitoring HARN in the workplace, (d) to reliably measure dose exposure levels, in order to support future epidemiological

  20. Changes in lipid membranes may trigger amyloid toxicity in Alzheimer's disease

    PubMed Central

    Drolle, Elizabeth; Negoda, Alexander; Hammond, Keely; Pavlov, Evgeny

    2017-01-01

    Amyloid-beta peptides (Aβ), implicated in Alzheimer’s disease (AD), interact with the cellular membrane and induce amyloid toxicity. The composition of cellular membranes changes in aging and AD. We designed multi-component lipid models to mimic healthy and diseased states of the neuronal membrane. Using atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM) and black lipid membrane (BLM) techniques, we demonstrated that these model membranes differ in their nanoscale structure and physical properties, and interact differently with Aβ1–42. Based on our data, we propose a new hypothesis that changes in lipid membrane due to aging and AD may trigger amyloid toxicity through electrostatic mechanisms, similar to the accepted mechanism of antimicrobial peptide action. Understanding the role of the membrane changes as a key activating amyloid toxicity may aid in the development of a new avenue for the prevention and treatment of AD. PMID:28767712

  1. Bioluminescent bioreporter pad biosensor for monitoring water toxicity.

    PubMed

    Axelrod, Tim; Eltzov, Evgeni; Marks, Robert S

    2016-01-01

    Toxicants in water sources are of concern. We developed a tool that is affordable and easy-to-use for monitoring toxicity in water. It is a biosensor composed of disposable bioreporter pads (calcium alginate matrix with immobilized bacteria) and a non-disposable CMOS photodetector. Various parameters to enhance the sensor's signal have been tested, including the effect of alginate and bacterium concentrations. The effect of various toxicants, as well as, environmental samples were tested by evaluating their effect on bacterial luminescence. This is the first step in the creation of a sensitive and simple operative tool that may be used in different environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Antibiotic toxicity and absorption in zebrafish using liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Fan; Qin, Wei; Zhang, Jing-Pu; Hu, Chang-Qin

    2015-01-01

    Evaluation of drug toxicity is necessary for drug safety, but in vivo drug absorption is varied; therefore, a rapid, sensitive and reliable method for measuring drugs is needed. Zebrafish are acceptable drug toxicity screening models; we used these animals with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in a multiple reaction monitoring mode to quantify drug uptake in zebrafish to better estimate drug toxicity. Analytes were recovered from zebrafish homogenate by collecting supernatant. Measurements were confirmed for drugs in the range of 10-1,000 ng/mL. Four antibiotics with different polarities were tested to explore any correlation of drug polarity, absorption, and toxicity. Zebrafish at 3 days post-fertilization (dpf) absorbed more drug than those at 6 h post-fertilization (hpf), and different developmental periods appeared to be differentially sensitive to the same compound. By observing abnormal embryos and LD50 values, zebrafish embryos at 6 hpf were considered to be suitable for evaluating embryotoxicity. Also, larvae at 3 dpf were adapted to measure acute drug toxicity in adult mammals. Thus, we can exploit zebrafish to study drug toxicity and can reliably quantify drug uptake with LC-MS/MS. This approach will be helpful for future studies of toxicology in zebrafish.

  3. Comparison of effluent toxicity results using Ceriodaphnia dubia cultured on several diets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Norberg-King, T.J.; Schmidt, S.

    1993-10-01

    Several diets have been proposed for Ceriodaphnia dubia, but no single diet has been universally accepted as optimal for toxicity testing. Although several diets for Ceriodaphnia dubia culturing and testing are commonly used, little or no data exist on whether toxicity varies with the diet. This study evaluated several combinations of yeast-Cerophyl-trout chow (YCT), Selenastrum capricornutum, and Selenastrum capricornutum-Cerophyl foods for routine culture performance and the sensitivity of the offspring in subsequent acute toxicity tests with effluents. Variations in the diets included use of a vitamin-fortified yeast added to the YCT, algae (Selenastrum capricornutum) grown in two different algal media,more » and different feeding rates of the algae-Cerophyl diets. Eleven diets were evaluated in a multigeneration feeding study, but only seven were used in subsequent toxicity tests. The young produced from each of the seven diets were tested in 48-h acute tests with three different effluents across the generations. Toxicity tests with the effluents gave LC50s that were within a factor of two of one another, regardless of the food used for culturing. These results indicate that several diets are satisfactory for culturing Ceriodaphnia dubia and that the results of the toxicity tests are comparable.« less

  4. Variation in toxicity response of Ceriodaphnia dubia to Athabasca oil sands coke leachates.

    PubMed

    Puttaswamy, Naveen; Turcotte, Dominique; Liber, Karsten

    2010-07-01

    Coke from the Athabasca (Alberta, Canada) oil sands operations may someday be integrated into reclamation landscapes. It is hypothesized that the metals associated with the solid coke may leach into the surrounding environment. Therefore, the main objectives of this study were to characterize the toxicity and chemistry of coke leachates collected from two field lysimeters (i.e. shallow lysimeter and deep lysimeter) over a period of 20months, as well as from other oil sands coke storage sites. In addition, a batch renewal leaching of coke was conducted to examine the rate of metals release. Chronic toxicity of key metals (e.g. Al, Mn, Ni and V) found in lysimeter coke leachate was evaluated separately. Toxicity test results revealed that whole coke leachates (100% v/v) were acutely toxic to Ceriodaphnia dubia; the 7-day LC50 values were always <25% v/v coke leachate. The deep lysimeter leachate was generally more toxic than the shallow lysimeter leachate, likely because of significantly higher concentrations of vanadium (V) found in the deep lysimeter leachate at all sampling times. Vanadium concentrations were higher than all other metals found in the leachate from both lysimeters, and in the batch renewal leaching study. Furthermore, V found in leachates collected from other oil sands field sites showed a concentration-response relationship with C. dubia survival. Mass balance calculations indicated that 94-98% of potentially leachable V fraction was still present in the coke from two field lysimeters. Evidence gathered from these assessments, including toxic unit (TU) calculations for the elements of concern, suggests that V was the likely cause of toxicity of the deep lysimeter leachate, whereas in the shallow lysimeter leachate both Ni and V could be responsible for the observed toxicity. 2010 Elsevier Ltd. All rights reserved.

  5. Characterization of the dinophysistoxin-2 acute oral toxicity in mice to define the Toxicity Equivalency Factor.

    PubMed

    Abal, Paula; Louzao, M Carmen; Cifuentes, José Manuel; Vilariño, Natalia; Rodriguez, Ines; Alfonso, Amparo; Vieytes, Mercedes R; Botana, Luis M

    2017-04-01

    Ingestion of shellfish with dinophysistoxin-2 (DTX2) can lead to diarrheic shellfish poisoning (DSP). The official control method of DSP toxins in seafood is the liquid chromatography-mass spectrometry analysis (LC-MS). However in order to calculate the total toxicity of shellfish, the concentration of each compound must be multiplied by individual Toxicity Equivalency Factor (TEF). Considering that TEFs caused some controversy and the scarce information about DTX2 toxicity, the aim of this study was to characterize the oral toxicity of DTX2 in mice. A 4-Level Up and Down Procedure allowed the characterization of DTX2 effects and the estimation of DTX2 oral TEF based on determination of the lethal dose 50 (LD50). DTX2 passed the gastrointestinal barrier and was detected in urine and feces. Acute toxicity symptoms include diarrhea and motionless, however anatomopathology study and ultrastructural images restricted the toxin effects to the gastrointestinal tract. Nevertheless enterocytes microvilli and tight junctions were not altered, disconnecting DTX2 diarrheic effects from paracellular epithelial permeability. This is the first report of DTX2 oral LD 50 (2262 μg/kg BW) indicating that its TEF is about 0.4. This result suggests reevaluation of the present TEFs for the DSP toxins to better determine the actual risk to seafood consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Wide acceptance angle, high concentration ratio, optical collector

    NASA Technical Reports Server (NTRS)

    Kruer, Mark A. (Inventor)

    1991-01-01

    A cassegrain optical system provides improved collection of off-axis light yet is still characterized by a high concentration ratio. The optical system includes a primary mirror for collecting incoming light and reflecting the light to a secondary mirror which, in turn, reflects the light to a solar cell or other radiation collection device. The primary mirror reflects incoming on-axis light onto an annular section of the secondary mirror and results in the reflection of a substantial amount of incoming off-axis light onto the remainder of the secondary mirror. Thus light which would otherwise be lost to the system will be captured by the collector. Furthermore, the off-axis sections of the secondary mirror may be of a different geometrical shape than the on-axis annular section so as to optimize the amount of off-axis light collected.

  7. Comparative toxicity of two azadirachtin-based neem pesticides to Daphnia pulex.

    PubMed

    Goktepe, Ipek; Plhak, Leslie C

    2002-01-01

    Azadirachtin (AZA)-based pesticides (Neemix and Bioneem) demonstrated toxicity in 48-h nonrenewal toxicity assays using Daphnia pulex at levels that were comparable with several organophosphate pesticides. The median lethal concentration (LC50) values for the two neem pesticides were found to be 0.028 and 0.033 microl/ml, respectively. The LC50 value for nonformulated (95% pure) AZA was determined to be 0.382 microg AZA/ml. Neemix and Bioneem were exposed to air and northern sky daylight in a light box at 24 and 37 degrees C for 1, 3, 6, and 9 d. Standard 48-h acute toxicity tests were used to determine the effect of aging in these dry environmental conditions. Neemix and Bioneem were also fractionated into volatile and nonvolatile fractions, and the toxicity of each was tested. Compared with Neemix, Bioneem remained toxic longer when exposed to light and air at 37 degrees C, indicating that this pesticide may be less prone to environmental degradation. When fractionated, the nonvolatile fractions for both pesticides exhibited significantly lower LC50 values than the full formulations. These results suggest that, depending on the application rate and environmental fate, AZA-based pesticides may have direct adverse effects on aquatic organisms and that the toxicity and stability of formulated pesticides depend on factors other than only the AZA concentration.

  8. Acute toxicity of 6 neonicotinoid insecticides to freshwater invertebrates.

    PubMed

    Raby, Melanie; Nowierski, Monica; Perlov, Dmitri; Zhao, Xiaoming; Hao, Chunyan; Poirier, David G; Sibley, Paul K

    2018-05-01

    Neonicotinoids are a group of insecticides commonly used in agriculture. Due to their high water solubility, neonicotinoids can be transported to surface waters and have the potential to be toxic to aquatic life. The present study assessed and compared the acute (48- or 96-h) toxicity of 6 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam) to 21 laboratory-cultured and field-collected aquatic invertebrates spanning 10 aquatic arthropod orders. Test conditions mimicked species' habitat, with lentic taxa exposed under static conditions, and lotic taxa exposed under recirculating systems. Median lethal concentrations (LC50s) and median effect concentrations (EC50s; immobility) were calculated and used to construct separate lethal- and immobilization-derived species sensitivity distributions for each neonicotinoid, from which 5th percentile hazard concentrations (HC5s) were calculated. The results showed that the most sensitive invertebrates were insects from the orders Ephemeroptera (Neocloeon triangulifer) and Diptera (Chironomus dilutus), whereas cladocerans (Daphnia magna, Ceriodaphnia dubia) were the least sensitive. The HC5s were compared with neonicotinoid environmental concentrations from Ontario (Canada) monitoring studies. For all neonicotinoids except imidacloprid, the resulting hazard quotients indicated little to no hazard in terms of acute toxicity to aquatic communities in Ontario freshwater streams. For the neonicotinoid imidacloprid, a moderate hazard was found when only invertebrate immobilization, and not lethality, data were considered. Environ Toxicol Chem 2018;37:1430-1445. © 2018 SETAC. © 2018 SETAC.

  9. Acute toxicity of peracetic acid (PAA) formulations to Ichthyophthirius multifiliis theronts.

    PubMed

    Straus, David L; Meinelt, Thomas

    2009-04-01

    Peracetic acid (PAA) is an antimicrobial disinfectant used in agriculture, food processing, and medical facilities. It has recently been suggested as a means to control infestations of Ichthyophthirius multifiliis. The purpose of this study was to determine the acute toxicity of two products containing 4.5% and 40% PAA to I. multifiliis theronts from two geographically separate isolates. Theronts were exposed to concentrations of PAA in 96-well plates containing groundwater at 23 degrees C. Acute toxicity was observed over a 4-h period. No significant difference in the median lethal concentration (LC(50)) estimates was evident between the two isolates at 4 h with the 4.5% PAA product (0.146 versus 0.108 mg/l PAA), while there was a statistical difference between the 4 h LC(50) with the 40% PAA product (0.274 versus 0.158 mg/l PAA). These results suggest that PAA is toxic to I. multifiliis theronts at low concentrations and that one of the isolates was more resistant to this compound.

  10. Toxicity of vanadium in soil on soybean at different growth stages.

    PubMed

    Yang, Jinyan; Wang, Mei; Jia, Yanbo; Gou, Min; Zeyer, Josef

    2017-12-01

    Vanadium(V) is present in trace amounts in most plants and widely distributed in soils. However, the environmental toxicity of V compound in soils is controversial. A greenhouse study with soybean from germination to bean production under exposure to pentavalent V [V(V)] was conducted to elucidate the interaction of plants and V fractions in soils and to evaluate the toxicity of V at different plant growth stages. Soybean growth has no effect on non-specific-bond and specific-bond fractions of V in soils, but V fractionation occurred in more extraction-resistant phases at high V concentrations. High concentrations of V(V) postponed the germination and growth of the soybeans. Bean production was less than half of that of the control at 500 mg kg -1 spiked V(V). For the 0 mg kg -1 spiked V(V) treated plants, the root was not the main location where V was retained. Vanadium in the soils at ≤ 250 mg kg -1 did not significantly affect the V concentration in the shoot and leaf of soybeans. With the increase in V concentration in soil, V concentrations in roots increased, whereas those in beans and pods decreased. From vegetative growth to the reproductive growth, the soybeans adsorbed more V and accumulated more V in the roots, with <20% transported to the aboveground parts. Hence, the analysis of V concentration in vegetative tissues or beans may not be a useful indicator for V pollution in soil. Meanwhile, the ratio of V concentration in cell wall to the total V concentration in the root increased with the increase in V(V) concentration in soils. Our results revealed that high concentrations of V inhibited soybean germination and biomass production. However, plants may produce self-defense systems to endure V toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Arsenic: Association of regional concentrations in drinking water with suicide and natural causes of death in Italy.

    PubMed

    Pompili, Maurizio; Vichi, Monica; Dinelli, Enrico; Erbuto, Denise; Pycha, Roger; Serafini, Gianluca; Giordano, Gloria; Valera, Paolo; Albanese, Stefano; Lima, Annamaria; De Vivo, Benedetto; Cicchella, Domenico; Rihmer, Zoltan; Fiorillo, Andrea; Amore, Mario; Girardi, Paolo; Baldessarini, Ross J

    2017-03-01

    Arsenic, as a toxin, may be associated with higher mortality rates, although its relationship to suicide is not clear. Given this uncertainty, we evaluated associations between local arsenic concentrations in tapwater and mortality in regions of Italy, to test the hypothesis that both natural-cause and suicide death rates would be higher with greater trace concentrations of arsenic. Arsenic concentrations in drinking-water samples from 145 sites were assayed by mass spectrometry, and correlated with local rates of mortality due to suicide and natural causes between 1980 and 2011, using weighted, least-squares univariate and multivariate regression modeling. Arsenic concentrations averaged 0.969 (CI: 0.543-1.396) µg/L, well below an accepted safe maximum of 10µg/L. Arsenic levels were negatively associated with corresponding suicide rates, consistently among both men and women in all three study-decades, whereas mortality from natural causes increased with arsenic levels. Contrary to an hypothesized greater risk of suicide with higher concentrations of arsenic, we found a negative association, suggesting a possible protective effect, whereas mortality from natural causes was increased, in accord with known toxic effects of arsenic. The unexpected inverse association between arsenic and suicide requires further study. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  12. THE ACUTE TOXICITY OF MAJOR ION SALTS TO CERIODAPHNIA DUBIA: I. INFLUENCE OF BACKGROUND WATER CHEMISTRY

    PubMed Central

    Mount, David R.; Erickson, Russell J.; Highland, Terry L.; Hockett, J. Russell; Hoff, Dale J.; Jenson, Correne T.; Norberg-King, Teresa J.; Peterson, Kira N.; Polaske, Zach; Wisniewski, Stephanie

    2018-01-01

    The ions Na+, K+, Ca2+, Mg2+, Cl−, SO42−, and HCO3−/CO32− (referred to here as “major ions”) are present in all fresh waters and are physiologically required by aquatic organisms, but can increase to harmful levels from a variety of anthropogenic activities. It is also known that the toxicities of major ion salts can vary depending on the concentrations of other ions, and understanding these relationships is key to establishing appropriate environmental limits. In this paper we present a series of experiments with Ceriodaphnia dubia to evaluate the acute toxicity of twelve major ion salts and to determine how toxicity of these salts varies as a function of background water chemistry. All salts except CaSO4 and CaCO3 were acutely toxic below saturation, with the lowest LC50s found for K salts. All ten salts that showed toxicity also showed some degree of reduced toxicity as the ionic content of the background water increased. Experiments that independently varied Ca:Mg ratio, Na:K ratio, Cl:SO4 ratio, and alkalinity/pH demonstrated that Ca concentration was the primary factor influencing the toxicities of Na and Mg salts, while the toxicities of K salts were primarily influenced by the concentration of Na. These experiments also indicated multiple mechanisms of toxicity and suggested important aspects of dosimetry: the toxicities of K, Mg, and Ca salts were best related to the chemical activity of the cation, while the toxicities of Na salts also reflected an influence of the anions and were well correlated with osmolarity. Understanding these relationships between major ion toxicity and background water chemistry should aid in the development of sensible risk assessment and regulatory standards. PMID:27167636

  13. Integration of Density Dependence and Concentration Response Models Provides an Ecologically Relevant Assessment of Populations Exposed to Toxicants

    EPA Science Inventory

    The assessment of toxic exposure on wildlife populations involves the integration of organism level effects measured in toxicity tests (e.g., chronic life cycle) and population models. These modeling exercises typically ignore density dependence, primarily because information on ...

  14. Phytoremediation of soils contaminated with toxic elements and radionuclides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cornish, J.E.; Goldberg, W.C.; Levine, R.S.

    1995-12-31

    At many US Department of Energy (US DOE) facilities and other sites, surface soils over relatively large areas are contaminated with heavy metals, radionuclides, and other toxic elements, often at only a relatively small factor above regulatory action levels. Cleanup of such sites presents major challenges, because currently available soil remediation technologies can be very expensive. In response, the US DOE`s Office of Technology Development, through the Western Environmental Technology Office, is sponsoring research in the area of phytoremediation. Phytoremediation is an emerging technology that uses higher plants to transfer toxic elements and radionuclides from surface soils into aboveground biomass.more » Some plants, termed hyperaccumulators, take up toxic elements in substantial amounts, resulting in concentrations in aboveground biomass over 100 times those observed with conventional plants. After growth, the plant biomass is harvested, and the toxic elements are concentrated and reclaimed or disposed of. As growing, harvesting, and processing plant biomass is relatively inexpensive, phytoremediation can be a low-cost technology for remediation of extensive areas having lightly to moderately contaminated soils. This paper reviews the potential of hyper- and moderate accumulator plants in soil remediation, provides some comparative cost estimates, and outlines ongoing work initiated by the US DOE.« less

  15. UV-photodegradation of desipramine: Impact of concentration, pH and temperature on formation of products including their biodegradability and toxicity.

    PubMed

    Khaleel, Nareman D H; Mahmoud, Waleed M M; Olsson, Oliver; Kümmerer, Klaus

    2016-10-01

    Desipramine (DMI) is a widely used tricyclic antidepressant, and it is the major metabolite of imipramine (IMI) and lofepramine (LMI); IMI and LMI are two of the most commonly used tricyclic antidepressants. If DMI enters the aquatic environment, it can be transformed by the environmental bacteria or UV radiation. Therefore, photolysis of DMI in water was performed using a simulated sunlight Xenon-lamp and a UV-lamp. Subsequently, the biodegradability of DMI and its photo-transformation products (PTPs) formed during its UV photolysis was studied. The influence of variable conditions, such as initial DMI concentration, solution pH, and temperature, on DMI UV photolysis behavior was also studied. The degree of mineralization of DMI and its PTPs was monitored. A Shimadzu HPLC-UV apparatus was used to follow the kinetic profile of DMI during UV-irradiation; after that, ion-trap and high-resolution mass spectrometry coupled with chromatography were used to monitor and identify the possible PTPs. The environmentally relevant properties and selected toxicity properties of DMI and the non-biodegradable PTPs were predicted using different QSAR models. DMI underwent UV photolysis with first-order kinetics. Quantum yields were very low. DOC values indicated that DMI formed new PTPs and was not completely mineralized. Analysis by means of high-resolution mass spectrometry revealed that the photolysis of DMI followed three main photolysis pathways: isomerization, hydroxylation, and ring opening. The photolysis rate was inversely proportional to initial DMI concentration. The pH showed a significant impact on the photolysis rate of DMI, and on the PTPs in terms of both formation kinetics and mechanisms. Although temperature was expected to increase the photolysis rate, it showed a non-significant impact in this study. Results from biodegradation tests and QSAR analysis revealed that DMI and its PTPs are not readily biodegradable and that some PTPs may be human and/or eco-toxic

  16. Acute phytotoxicity of seven metals alone and in mixture: Are Italian soil threshold concentrations suitable for plant protection?

    PubMed

    Baderna, Diego; Lomazzi, Eleonora; Pogliaghi, Alberto; Ciaccia, Gianluca; Lodi, Marco; Benfenati, Emilio

    2015-07-01

    Metals can pollute soils in both urban and rural areas with severe impacts on the health of humans, plants and animals living there. Information on metal toxicity is therefore important for ecotoxicology. This study investigated the phytotoxicity of different metals frequently found as pollutants in soils: arsenic, cadmium, chromium, lead, mercury, nickel and zinc. Cucumber (Cucumis sativus), sorghum (Sorghum saccharatum) and cress (Lepidium sativum) seeds were used as models for other plants used in human nutrition such as cereals, rice, fruits and vegetables. The 72-h germination rate and root elongations were selected as short-term ecotoxicological endpoints in seeds exposed to single metals and mixtures. Metals were spiked onto OECD standard soils in concentrations comparable to current Italian contamination threshold concentrations for residential and commercial soils. Arsenic, chromium, mercury and nickel were the most toxic metals in our experimental conditions, particularly to cress seeds (5.172, 152 and 255.4 mg/kg as 72 h IC50 for arsenic, mercury and nickel respectively). Italian limits were acceptable for plant protection only for exposure to each metal alone but not for the mixtures containing all the metals concentrations expected by their respective legislative threshold. The effects of the mixture were class-specific: trends were comparable in dicots but different in monocots. The response induced by the mixture at high concentrations differed from that theoretically obtainable by summing the effects of the individual metals. This might be due to partial antagonism of the metals in soil or to the formation of complexes between the metals, which reduce the bioavailability of the pollutants for plants. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Bridging the Gap between Social Acceptance and Ethical Acceptability.

    PubMed

    Taebi, Behnam

    2017-10-01

    New technology brings great benefits, but it can also create new and significant risks. When evaluating those risks in policymaking, there is a tendency to focus on social acceptance. By solely focusing on social acceptance, we could, however, overlook important ethical aspects of technological risk, particularly when we evaluate technologies with transnational and intergenerational risks. I argue that good governance of risky technology requires analyzing both social acceptance and ethical acceptability. Conceptually, these two notions are mostly complementary. Social acceptance studies are not capable of sufficiently capturing all the morally relevant features of risky technologies; ethical analyses do not typically include stakeholders' opinions, and they therefore lack the relevant empirical input for a thorough ethical evaluation. Only when carried out in conjunction are these two types of analysis relevant to national and international governance of risky technology. I discuss the Rawlsian wide reflective equilibrium as a method for marrying social acceptance and ethical acceptability. Although the rationale of my argument is broadly applicable, I will examine the case of multinational nuclear waste repositories in particular. This example will show how ethical issues may be overlooked if we focus only on social acceptance, and will provide a test case for demonstrating how the wide reflective equilibrium can help to bridge the proverbial acceptance-acceptability gap. © 2016 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

  18. Determination of pesticides and toxic potency of rainwater samples in western Greece.

    PubMed

    Rouvalis, Angela; Karadima, Constantina; Zioris, Ioannis V; Sakkas, Vasilios A; Albanis, Triantafyllos; Iliopoulou-Georgudaki, Joan

    2009-03-01

    Rainwater samples from four municipalities located in Achaia Prefecture, Greece, were collected from March to September 2006. The toxic potency of pollutants present in 36 rainwater samples was tested using Daphnia pulex. The pesticide determination was conducted with GC-MS. Only phosphamidon was detected, which appeared in 52% and 13% of the rural and urban areas, respectively. The toxicity of rainwater was determined in 52% and 46.7% of the rural and urban area samples, respectively. Chemical analyses showed that in rural areas, the PO(4)(3-) ions had higher concentrations than in urban areas. On the other hand, the SO(4)(2-), NO(-)(3), and NO(-)(2) anions are more highly concentrated in urban areas. Correlation analysis proved that the toxicity of the rainwater samples is moderate, affected by the presence of the insecticide only in the rural areas. The results indicated that toxicity can be directly assessed via bioassays, even when unknown pollutants are present.

  19. Defining appropriate methods for studying toxicities of trace metals in nutrient solutions.

    PubMed

    Li, Zhigen; Wang, Peng; Menzies, Neal W; Kopittke, Peter M

    2018-01-01

    The use of inappropriate experimental conditions for examining trace metal phytotoxicity results in data of questionable value. The present study aimed to identify suitable parameters for study of phytotoxic metals in nutrient solutions. First, the literature was reviewed to determine the concentration of six metals (Cd, Cu, Hg, Ni, Pb, and Zn) from solution of contaminated soils. Next, the effects of pH, P, Cl, NO 3 , and four Fe-chelators were investigated by using thermodynamic modelling and by examining changes in root elongation rate of soybean (Glycine max cv. Bunya). The literature review identified that the solution concentrations of metals in soils were low, ranging from (µM) 0.069-11Cd, 0.19-15.8 Cu, 0.000027-0.000079 Hg, 1.0-8.7 Ni, 0.004-0.55 Pb, and 0.4-36.3 Zn. For studies in nutrient solution, pH should generally be low given its effects on solubility and speciation, as should the P concentration due to the formation of insoluble phosphate salts. The concentrations of Cl, NO 3 , and various chelators also influence metal toxicity through alteration of metal speciation. The nutrient solutions used to study metal toxicity should consider environmentally-relevant conditions especially for metal concentrations, with concentrations of other components added at levels that do not substantially alter metal toxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. A Microfluidic Device for Continuous Sensing of Systemic Acute Toxicants in Drinking Water

    PubMed Central

    Zhao, Xinyan; Dong, Tao

    2013-01-01

    A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+), zinc (Zn2+), potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU) obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety. PMID:24300075

  1. QSAR prediction of additive and non-additive mixture toxicities of antibiotics and pesticide.

    PubMed

    Qin, Li-Tang; Chen, Yu-Han; Zhang, Xin; Mo, Ling-Yun; Zeng, Hong-Hu; Liang, Yan-Peng

    2018-05-01

    Antibiotics and pesticides may exist as a mixture in real environment. The combined effect of mixture can either be additive or non-additive (synergism and antagonism). However, no effective predictive approach exists on predicting the synergistic and antagonistic toxicities of mixtures. In this study, we developed a quantitative structure-activity relationship (QSAR) model for the toxicities (half effect concentration, EC 50 ) of 45 binary and multi-component mixtures composed of two antibiotics and four pesticides. The acute toxicities of single compound and mixtures toward Aliivibrio fischeri were tested. A genetic algorithm was used to obtain the optimized model with three theoretical descriptors. Various internal and external validation techniques indicated that the coefficient of determination of 0.9366 and root mean square error of 0.1345 for the QSAR model predicted that 45 mixture toxicities presented additive, synergistic, and antagonistic effects. Compared with the traditional concentration additive and independent action models, the QSAR model exhibited an advantage in predicting mixture toxicity. Thus, the presented approach may be able to fill the gaps in predicting non-additive toxicities of binary and multi-component mixtures. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Photoenhanced toxicity of a weathered oil on Ceriodaphnia dubia reproduction

    USGS Publications Warehouse

    Calfee, R.D.; Little, E.E.; Cleveland, L.; Barron, M.G.

    1999-01-01

    Traditionally, the toxic effects of petroleum have been investigated by conducting studies in the absence of ultraviolet radiation (UV). Photomediated toxicity is often not considered, and the toxic effects of an oil spill can be grossly underestimated. The toxicity of a weathered oil collected from a monitoring well at an abandoned oil field toCeriodaphnia dubia was examined in the presence of UV. A solar simulator equipped with UVB, UVA, and cool white lamps was used to generate environmentally comparable solar radiation intensities.C. dubia were exposed to six concentrations of water accommodated fractions (WAF) of weathered oil in conjunction with three levels of laboratory simulated UV (Reference = < 0.002 μW/cm2UVB; 3.0 μW/cm2UVA; Low = 0.30 μW/cm2 UVB; 75.0 μW/cm2 UVA; High = 2.0 μW/cm2 UVB; 340.0 μW/cm2UVA) and visible light. Seven day static renewal bioassays were used to characterize WAF/UV toxicity. WAF toxicity significantly (p < 0.05) increased when the organisms were exposed to WAF in the presence of UV. The photoenhanced toxicity of the WAF increased with WAF concentration within each UV regime. Relative to the reference light regime, the average number of neonates from adults exposed to 1.6 mg TPH/L decreased significantly by 20% within the low light regime, and by 60% within the high light regime. These results indicate that organisms exposed to dissolved-phase weathered oil in the presence of environmentally realistic solar radiation, exhibit 1.3–2.5 times greater sensitivity, relative to organisms exposed under traditional laboratory fluorescent lighting.

  3. [Toxicity and influencing factors of liquid chlorine on chironomid larvae].

    PubMed

    Sun, Xing-Bin; Cui, Fu-Yi; Zhang, Jin-Song; Guo, Zhao-Hai; Xu, Feng; Liu, Li-Jun

    2005-09-01

    The excessive propagation of Chironomid larvae (red worm) in the sedimentation tanks is a difficult problem for the normal function of waterworks. The toxic effect of liquid chlorine on the different instar larvae of Chironomid was studied using distilled water as test sample. Furthermore, the effect of pH value, organic matter content, ammonia nitrogen, and algae content on toxicity of liquid chlorine was observed. The results show that the tolerance of Chironomid larvae to liquid chlorine is strengthened with the increase in instar. The 24h semi-lethal concentration (LC50) of liquid chlorine to the 4th instar larvae of Chironomid is 3.39 mg/L. Low pH value and high algae content are helpful to improve the toxic effect of liquid chlorine to Chironomid larvae. In neutral water body, the increase in organic matter content results in the decrease in the death rate of Chironomid larvae. The toxicity of liquid chlorine differs greatly in different concentrations of ammonia nitrogen. The death rate of the 4th instar larvae of Chironomid in raw water is higher by contrast with that in sedimentation tanks water for 24h disposal with various amount of liquid chlorine.

  4. Joint toxicity of methamidophos and cadmium acting on Abelmoschus manihot.

    PubMed

    Wang, Xiao-Fei; Zhou, Qi-Xing

    2005-01-01

    Joint toxicity of methamidophos and cadmium (Cd) on the ornamental Abelmoschus manihot was firstly examined and compared with single-factor effects of the two pollutants using ecotoxicological indexes including the inhibitory rate of seed germination, root elongation and inhibitory concentration 50% (IC50). The results indicated that methamidophos and Cd had unobvious( p > 0.05) effects on seed germination of the ornamental. There were significant( p < 0.05) inhibitory effects of Cd on root elongation of the tested plant. When the concentration of added Cd was low( < 20 mg/L), significant antagonistic effects on root elongation were observed. And synergic effects were observed when Cd was added in high dose( > 20 mg/L). However, the analysis of joint effects indicated that there were antagonistic effects between Cd and methamidophos under all the treatments. At the high concentration of Cd, joint toxicity of methamidophos and Cd was more dependent on concentration of Cd.

  5. Triazole-induced toxicity in developing rare minnow (Gobiocypris rarus) embryos.

    PubMed

    Zhu, Bin; Liu, Lei; Gong, Yu-Xin; Ling, Fei; Wang, Gao-Xue

    2014-12-01

    Using rare minnow (Gobiocypris rarus) at early-life stages as experimental models, the developmental toxicity of five widely used triazole fungicides (myclobutanil, fluconazole, flusilazole, triflumizole, and epoxiconazole) were investigated following exposure to 1-15 mg/L for 72 h. Meanwhile, morphological parameters (body length, body weight, and heart rate), enzyme activities (superoxide dismutase (SOD), glutathione S-transferase (GST), adenosine triphosphatase (ATPase), and acetyl cholinesterase (AChE)), and mRNA levels (hsp70, mstn, mt, apaf1, vezf1, and cyp1a) were also recorded following exposure to 0.2, 1.0, and 5.0 mg/L for 72 h. Results indicated that increased malformation and mortality, decreased body length, body weight, and heart rate provide a concentration-dependent pattern; values of 72 h LC50 (median lethal concentration) and EC50 (median effective concentration) ranged from 3 to 12 mg/L. Most importantly, the results of the present study suggest that even at the lowest concentration, 0.2 mg/L, five triazole fungicides also caused notable changes in enzyme activities and mRNA levels. Overall, the present study points out that those five triazole fungicides are highly toxic to the early development of G. rarus embryos. The information presented in this study will be helpful in better understanding the toxicity induced by triazole fungicides in fish embryos.

  6. Hepatic concentrations of copper and other metals in dogs with and without chronic hepatitis.

    PubMed

    Cedeño, Y; López-Alonso, M; Miranda, M

    2016-12-01

    Defects in copper metabolism have been described in several dog breeds, and recently, it has been suggested that changes in other essential trace elements could be involved in the pathogenesis of hepatic disease. This study measured hepatic copper accumulation and its interactions with other essential trace and toxic metals in dogs diagnosed with chronic hepatitis. Liver samples of 20 chronic hepatitis and 20 healthy dogs were collected. Samples were acid digested, and essential metals (cobalt, copper, iron, manganese, molibdenum, selenium and zinc) and toxic metals (arsenic, cadmium, mercury and lead) were analysed by inductively-coupled plasma mass spectrometry. Copper concentrations were significantly higher in dogs affected by hepatic disease than in controls. Dogs having chronic hepatitis with liver copper concentration greater than 100 mg/kg wet weight showed statistically higher cobalt, manganese and zinc concentrations than dogs having chronic hepatitis with liver copper concentrations less than 100 mg/kg wet weight and controls. Toxic metal concentrations were low - in all cases below the threshold associated with toxicity in dogs. Dogs with chronic hepatitis not only have increased concentrations of copper in the liver but also increased concentrations of cobalt, manganese and zinc; measurement of these elements may perhaps aid in diagnosis of liver disease in dogs. © 2016 British Small Animal Veterinary Association.

  7. Sensory Acceptability of Iron-Fortified Red Lentil (Lens culinaris Medik.) Dal.

    PubMed

    Podder, Rajib; Khan, Shaan M; Tar'an, Bunyamin; Tyler, Robert T; Henry, Carol J; Jalal, Chowdhury; Shand, Phyllis J; Vandenberg, Albert

    2018-03-01

    Panelists in Saskatoon, Canada (n = 45) and Dhaka, Bangladesh (n = 98) participated in sensory evaluations of the sensory properties of both cooked and uncooked dehulled red lentil dal fortified with FeSO 4 ·7H 2 O, NaFeEDTA or FeSO 4 ·H 2 O at fortificant Fe concentrations of 800, 1,600 (both cooked and uncooked), or 2,800 ppm. Appearance, odor, and overall acceptability of cooked and uncooked samples were rated using a 9-point hedonic scale (1 = dislike extremely to 9 = like extremely). Taste and texture were rated for the cooked samples prepared as typical south Asian lentil meals. Significant differences in sensory quality were observed among all uncooked and cooked samples at both locations. Overall, scores for all sensory attributes and acceptability of uncooked lentil decreased with increasing concentration of Fe in the fortificant; however, Fe fortification (particularly with NaFeEDTA) had small effects on acceptability. Panelists from Saskatoon provided a wider range of scores than those from Bangladesh for all attributes of cooked lentil. Overall, sensory evaluation of Fe fortification using NaFeEDTA minimally affected consumer perception of color, taste, texture, odor, and overall acceptability of cooked lentil. Reliability estimates (Cronbach's alpha [CA]) indicated that consumer scores were generally consistent for all attributes of all lentil samples (mean CA > 0.80). NaFeEDTA was found to be the most suitable Fe fortificant for lentil based on consumer acceptability. Consumption of 45 to 50 g of NaFeEDTA-fortified lentil (fortificant Fe concentration of 1,600 ppm) per day meets the estimated average requirements (EARs) of Fe for humans (10.8 to 29.4 mg). Iron fortification of dehulled lentil dal may change organoleptic attributes that can influence consumer acceptability. Sensory evaluation by consumers helps to determine the effect on appearance, odor, taste, texture, and overall acceptability of fortified lentils. In this study, consumer

  8. Toxic cyanobacteria and cyanotoxins in public hot springs in Saudi Arabia.

    PubMed

    Mohamed, Zakaria A

    2008-01-01

    Toxic cyanobacteria are well reported in rivers, lakes and even marine environments, but the toxin production of cyanobacteria in hot springs is largely unexplored. Therefore, the present study investigated the presence of toxic cyanobacteria and cyanotoxins in public hot springs in Saudi Arabia. The results of an enzyme-linked immunosorbent assay (ELISA) revealed that Saudi spring cyanobacterial mats contained microcystins (MCYSTs) at concentrations ranging from 468 to 512.5 microg g(-1). The Limulus amebocyte lystae (LAL) assay detected lipopolysaccharide (LPS) endotoxins in these mats at concentrations ranging from 433.3 to 506.8 EU g(-1). MCYSTs and endotoxins were also detected in spring waters at levels of 5.7 microg l(-1) and 640 EU ml(-1), respectively, exceeding WHO's provisional guideline value for MCYST-LR in drinking-water. High-performance liquid chromatography (HPLC) analysis revealed that only Oscillatoria limosa and Synechococcus lividus can produce MCYSTs with a profile consisting of MCYST-RR and -LR. Based on the LAL assay, 12 out of 17 cyanobacterial species contained LPS at concentrations ranging from 0.93 to 21.06 EU g(-1). However, not all LPS of these species were toxic to mice. This study suggests that the hot springs in the world including Saudi Arabia should be screened for toxic cyanobacteria to avoid the exposure of people recreating and bathing in spring waters to cyanobacterial toxins.

  9. Influence of salinity and organic carbon on the chronic toxicity of silver to mysids (Americamysis bahia) and silversides (Menidia beryllina).

    PubMed

    Ward, Timothy J; Boeri, Robert L; Hogstrand, Christer; Kramer, James R; Lussier, Suzanne M; Stubblefield, William A; Wyskiel, Derek C; Gorsuch, Joseph W

    2006-07-01

    Tests were conducted with mysids (Americamysis bahia) and silversides (Menidia beryllina) to evaluate the influence of salinity and organic carbon on the chronic toxicity of silver. During 7- and 28-d tests conducted at 10, 20, and 30% per hundred salinity, higher concentrations of dissolved silver generally were required to cause a chronic effect as the salinity of the seawater was increased. The 28-d mysid and silverside 20%-effective concentration values (expressed as dissolved silver) ranged from 3.9 to 60 and from 38 to 170 microg/L, respectively, over the salinity range. This pattern was not observed when the same test results were evaluated against the concentrations of free ionic silver (measured directly during toxicity tests), as predicted by the free-ion activity model. Increasing the concentration of dissolved organic carbon from 1 mg/L to the apparent maximum achievable concentration of 6 mg/L in seawater caused a slight decrease in chronic toxicity to silversides but had no effect on the chronic toxicity to mysids. The possible additive toxicity of silver in both food and water also was investigated. Even at the maximum achievable foodborne concentration, the chronic toxicity of silver added to the water was not affected when silver was also added to the food, based on the most sensitive endpoint (growth). However, although fecundity was unaffected at all five tested concentrations during the test with silver in water only, it was significantly reduced at the two highest waterborne silver concentrations (12 and 24 microg/L) during the test with silver dosed into food and water.

  10. Assessment of Runoff Toxicity from Coated Surfaces

    EPA Science Inventory

    Presented in this paper are results from a field and laboratory study of the potential runoff toxicity from coated surfaces. The study results qualified and quantified the types and concentrations of pollutants in runoff from surfaces sealed with a variety of products. Coatings a...

  11. Large Dataset of Acute Oral Toxicity Data Created for Testing in Silico Models (ASCCT meeting)

    EPA Science Inventory

    Acute toxicity data is a common requirement for substance registration in the US. Currently only data derived from animal tests are accepted by regulatory agencies, and the standard in vivo tests use lethality as the endpoint. Non-animal alternatives such as in silico models are ...

  12. DIGE-based protein expression analysis of B[a]P-exposed hepatoma cells reveals a complex stress response including alterations in oxidative stress, cell cycle control, and cytoskeleton motility at toxic and subacute concentrations.

    PubMed

    Dautel, Franziska; Kalkhof, Stefan; Trump, Saskia; Michaelson, Jacob; Beyer, Andreas; Lehmann, Irina; von Bergen, Martin

    2011-02-04

    Although the effects of high concentrations of the carcinogen benzo[a]pyrene (B[a]P) have been studied extensively, little is known about its effects at subacute toxic concentrations, which are typical for environmental pollutants. We exposed murine Hepa1c1c7 cells to a toxic concentration (5 μM) and a subacute concentration (50 nM) of B[a]P over a period of 2-24 h to differentiate between acute and pseudochronic effects and conducted a time-course analysis of B[a]P-influenced protein expression by DIGE. In total, a set of 120 spots were found to be significantly altered due to B[a]P exposure of which 112 were subsequently identified by mass spectrometry. Clustering and principal component analysis were conducted to identify sets of proteins responding in a concerted manner to the exposure. Our results indicate an immediate response to the contaminant at the protein level and demonstrate that B[a]P exposure alters the cellular response by disturbing proteins involved in oxidative stress, cell cycle regulation, apoptosis, and cytoskeleton organization. Furthermore, network analysis of protein-protein interactions revealed a complex network of interacting, B[a]P-regulated proteins mostly belonging to the cytoskeleton organization and several signal transduction pathways.

  13. Comparative assessment of three in vitro exposure methods for combustion toxicity.

    PubMed

    Lestari, Fatma; Markovic, Boban; Green, Anthony R; Chattopadhyay, Gautam; Hayes, Amanda J

    2006-01-01

    A comparative assessment of three approaches for the use of human cells in vitro to investigate combustion toxicity was conducted. These included one indirect and two direct (passive and dynamic) exposure methods. The indirect method used an impinger system in which culture medium was used to trap the toxicants, whilst the direct exposure involved the use of a Horizontal Harvard Navicyte Chamber at the air/liquid interface. The cytotoxic effects of thermal decomposition products were assessed using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay (Promega) on a selection of human cells including: HepG2, A549 and skin fibroblasts. A small scale laboratory fire test using a vertical tube furnace was designed for the generation of combustion products. Polymethyl methacrylate (PMMA) was selected as a model polymer to study the cytotoxic effects of combustion products. NOAEC (no observable adverse effect concentration), IC10 (10% inhibitory concentration), IC50 (50% inhibitory concentration) and TLC (total lethal concentration) values were determined from dose response curves. Assessment using the NRU (neutral red uptake) and ATP (adenosine triphosphate) assays on human lung derived cells (A549) was also undertaken. Comparison between in vitro cytotoxicity results against published toxicity data for PMMA combustion and predicted LC50 (50% lethal concentration) values calculated from identified compounds using GCMS (gas chromatography mass spectrometry) was determined. The results suggested that the indirect exposure method did not appear to simulate closely exposure via inhalation, whilst exposure at the air/liquid interface by using the dynamic method proved to be a more representative method of human inhalation. This exposure method may be a potential system for in vitro cytotoxicity testing in combustion toxicity. Copyright 2005 John Wiley & Sons, Ltd.

  14. DEPLOYMENT OF A WATER QUALITY EARLY WARNING SYSTEM USING ON-LINE TOXICITY MONITORS

    EPA Science Inventory

    Contaminants are of concern when they are found in concentrations that are toxic to plants and/or animals. On–line Toxicity Monitors (OTMs) integrate all factors resulting in stress including physical and chemical qualities. This is important because of the limitations of c...

  15. Acute and chronic toxicity of six anticancer drugs on rotifers and crustaceans.

    PubMed

    Parrella, Alfredo; Lavorgna, Margherita; Criscuolo, Emma; Russo, Chiara; Fiumano, Vittorio; Isidori, Marina

    2014-11-01

    The growing use of cytostatic drugs is gaining relevance as an environmental concern. Environmental and distribution studies are increasing due to the development of accurate analytical methods, whereas ecotoxicological studies are still lacking. The aim of the present study was to investigate the acute and chronic toxicity of six cytostatics (5-fluorouracil, capecitabine, cisplatin, doxorubicin, etoposide, and imatinib) belonging to five classes of Anatomical Therapeutic Classification (ATC) on primary consumers of the aquatic chain (Daphnia magna, Ceriodaphnia dubia, Brachionus calyciflorus, and Thamnocephalus platyurus). Acute ecotoxicological effects occurred at concentrations in the order of mgL(-)(1), higher than those predicted in the environment, and the most acutely toxic drugs among those tested were cisplatin and doxorubicin for most aquatic organisms. For chronic toxicity, cisplatin and 5-fluorouracil showed the highest toxic potential in all test organisms, inducing 50% reproduction inhibition in crustaceans at concentrations on the order of μgL(-)(1). Rotifers were less susceptible to these pharmaceuticals. On the basis of chronic results, the low effective concentrations suggest a potential environmental risk of cytostatics. Thus, this study could be an important starting point for establishing the real environmental impact of these substances. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Risk assessment of an abandoned pyrite mine in Spain based on direct toxicity assays.

    PubMed

    García-Gómez, Concepción; Sánchez-Pardo, Beatriz; Esteban, Elvira; Peñalosa, Jesús Manuel; Fernández, María Dolores

    2014-02-01

    This research reports the risk assessment of an abandoned pyrite mine using direct toxicity assays of soil and groundwater samples taken at the site. The toxicity of As and heavy metals from mining soils to soil and aquatic organisms was studied using the Multispecies Soil System (MS-3) in soil columns. Ecotoxicological assessment was performed with soil samples diluted with a control soil at concentrations of 12.5, 25, 50 and 100% test soil/soil (w/w). In this way, changes in the mobility and bioavailability of soil contaminants due to changes in geochemical soil properties via soil dilution were studied. The toxicity of water samples was tested on algae and Daphnia magna. The assessment of the mining area indicated that the current presence of As and heavy metals at the site may cause injuries to soil and aquatic organisms in the entire research area. Moreover, this investigation demonstrated that changes in geochemical conditions can increase the availability of arsenic and, consequently, the environmental risk of these soils. A good correlation was not found between toxicity parameters and the concentrations of soil contaminants based on total and extracted element concentrations. This finding reinforces the usefulness of direct toxicity assays for evaluating environmental risk. © 2013.

  17. Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking).

    PubMed

    Voss, Kenneth; Ryu, Dojin; Jackson, Lauren; Riley, Ronald; Gelineau-van Waes, Janee

    2017-08-23

    Fumonisins are mycotoxins found in corn. They are toxic to animals and cause cancer in rodents and neural tube defects in LM/Bc mice. Reducing their concentrations in corn-based foods is therefore desirable. Chemical analysis or in vitro bioassays of food extracts might not detect toxic fumonisin reaction products that are unknown or unextractable from food matrices, thus potentially underestimating in vivo toxicity. The effectiveness of two common cooking methods, extrusion and nixtamalization (alkaline cooking), to reduce the toxicity of fumonisin-contaminated corn grits (extrusion) and whole kernel corn (nixtamalization) was shown by means of rat feeding bioassays using fumonisin-specific kidney effects as indicators of potential toxicity. A third bioassay showed that in contrast to fumonisin B 1 (FB 1 ), hydrolyzed fumonisin B 1 (HFB 1 ; formed from FB 1 during nixtamalization) did not cause neural tube defects in LM/Bc mice. The findings indicate that extrusion and nixtamalization reduce the potential toxicity of FB 1 -contaminated corn.

  18. Nonimaging concentrators for photovoltaic arrays in space

    NASA Technical Reports Server (NTRS)

    Winston, R.; Greenman, P.; Rockey, D.

    1981-01-01

    Two stage concentrators are studied in order to design an optimum concentrator for photovoltaic arrays in space. The study is directed at designs with two-dimensional geometries because they are better suited to moderate concentrations of about 10 X to 50 X, and because the instantaneous flux distribution is more uniform. It is found that with an f/0.5 primary, where f is the focal length of the primary, the flux distribution is very smooth regardless of the angle of incidence of the radiation. As the focal ratio is increased, peaks in the distribution begin to appear. The nonuniformities can be reduced by introducing small, closely spaced distortions into the reflecting surfaces, and practical arrays can achieve a concentration of 10 when the acceptance half angle is 4.25 deg or 50 when the acceptance half angle is + or - 1 deg.

  19. Chronic toxicity of five metals to the polar marine microalga Cryothecomonas armigera - Application of a new bioassay.

    PubMed

    Koppel, Darren J; Gissi, Francesca; Adams, Merrin S; King, Catherine K; Jolley, Dianne F

    2017-09-01

    The paucity of ecotoxicological data for Antarctic organisms is impeding the development of region-specific water quality guidelines. To address this limitation, toxicity testing protocols need to be developed to account for the unique physiology of polar organisms, in particular their slow growth rates. In this study, a toxicity test protocol was developed to investigate the toxicities of five metals to the polar marine microalga Cryothecomonas armigera. The concentrations which reduced population growth rate by 10% (EC10) after 24-d for Cu, Pb, Zn, Cd and Ni were 21.6, 152, 366, 454, and 1220 μg.L -1 , respectively. At the concentrations used in tests, only Cu and Ni were sufficiently toxic to enable the derivation of EC50 values of 63.1 and 1570 μg.L -1 respectively. All metals affected C. armigera's cellular physiology including cellular chlorophyll a fluorescence, cell complexity and size, and lipid concentrations. However, no changes to cellular membrane permeability were observed. The reduction in cellular lipid concentrations was a more sensitive indicator of toxicity for Cd, Ni, and Pb than growth rate inhibition, with EC10 values of 89, 894, and 11 μg.L -1 , respectively, highlighting its potential as a sensitive measure of metal toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Petroleum Hydrocarbon Mixture Toxicity and a Trait Based Approach to Soil Invertebrate Species for Site Specific Risk Assessments.

    PubMed

    Gainer, Amy; Cousins, Mark; Hogan, Natacha; Siciliano, Steven D

    2018-05-05

    Although petroleum hydrocarbons (PHCs) released to the environment typically occur as mixtures, PHC remediation guidelines often reflect individual substance toxicity. It is well documented that groups of aliphatic PHCs act via the same mechanism of action, nonpolar narcosis and, theoretically, concentration addition mixture toxicity principles apply. To assess this theory, ten standardized acute and chronic soil invertebrate toxicity tests on a range of organisms (Eisenia fetida, Lumbricus terrestris, Enchytraeus crypticus, Folsomia candida, Oppia nitens and Hypoaspis aculeifer) were conducted with a refined PHC binary mixture. Reference models for concentration addition and independent action were applied to the mixture toxicity data with consideration of synergism, antagonism and dose level toxicity. Both concentration addition and independent action, without further interactions, provided the best fit with observed response to the mixture. Individual fraction effective concentration values were predicted from optimized, fitted reference models. Concentration addition provided a better estimate than independent action of individual fraction effective concentrations based on comparison with available literature and species trends observed in toxic responses to the mixture. Interspecies differences in standardized laboratory soil invertebrate species responses to PHC contaminated soil was reflected in unique traits. Diets that included soil, large body size, permeable cuticle, low lipid content, lack of ability to molt and no maternal transfer were traits linked to a sensitive survival response to PHC contaminated soil in laboratory tests. Traits linked to sensitive reproduction response in organisms tested were long life spans with small clutch sizes. By deriving single fraction toxicity endpoints considerate of mixtures, we reduce resources and time required in conducting site specific risk assessments for the protection of soil organism's exposure pathway. This