Science.gov

Sample records for direct soil exposures

  1. Impact of Direct Soil Exposures from Airborne Dust and Geophagy on Human Health

    PubMed Central

    Sing, David; Sing, Charles F

    2010-01-01

    Over evolutionary time humans have developed a complex biological relationship with soils. Here we describe modes of soil exposure and their biological implications. We consider two types of soil exposure, the first being the continuous exposure to airborne soil, and the second being dietary ingestion of soils, or geophagy. It may be assumed that airborne dust and ingestion of soil have influenced the evolution of particular DNA sequences which control biological systems that enable individual organisms to take advantage of, adapt to and/or protect against exposures to soil materials. We review the potential for soil exposure as an environmental source of epigenetic signals which may influence the function of our genome in determining health and disease. PMID:20617027

  2. Subchronic exposure of mice to Love Canal soil contaminants

    SciTech Connect

    Silkworth, J.B.; McMartin, D.N.; Rej, R.; Narang, R.S.; Stein, V.B.; Briggs, R.G.; Kaminsky, L.S.

    1984-04-01

    The health hazard potential of soil collected from the surface of the Love Canal chemical dump site in Niagara Falls, New York, was assessed in 90-day exposure studies. Female CD-1 mice were exposed to two concentrations of the volatile components of 1 kg of soil with and without direct soil contact. Control mice were identically housed but without soil. The soil was replaced weekly and 87 compounds were detected in the air in the cages above fresh and 7-day-old soil as analyzed by gas chromatography/mass spectrometry. The concentration of many of these compounds decreased during the 7-day exposure cycle. Histopathologic, hematologic, and serum enzyme studies followed necropsy of all mice. There was no mortality of mice exposed for up to 90 days under any condition. Thymus and spleen weights relative to body weight were increased after 4 weeks of exposure by inhalation but not after 8 or 12 weeks of exposure. alpha-, beta-, and delta- Benzenehexachlorides , pentachlorobenzene, and hexachlorobenzene were detected in liver tissue from these animals. Mice exposed to 5- to 10-fold elevated concentration of volatiles had increased body and relative kidney weights. There was no chemically induced lesion in any animal exposed only to the volatile soil contaminants. Mice exposed by direct contact with the soil without elevated volatile exposure had increased body (10%) and relative liver weights (169%). Centrolobular hepatocyte hypertrophy, which involved 40 to 70% of the lobules, was observed in all mice in this group.

  3. Subchronic exposure of mice to Love Canal soil contaminants.

    PubMed

    Silkworth, J B; McMartin, D N; Rej, R; Narang, R S; Stein, V B; Briggs, R G; Kaminsky, L S

    1984-04-01

    The health hazard potential of soil collected from the surface of the Love Canal chemical dump site in Niagara Falls, New York, was assessed in 90-day exposure studies. Female CD-1 mice were exposed to two concentrations of the volatile components of 1 kg of soil with and without direct soil contact. Control mice were identically housed but without soil. The soil was replaced weekly and 87 compounds were detected in the air in the cages above fresh and 7-day-old soil as analyzed by gas chromatography/mass spectrometry. The concentration of many of these compounds decreased during the 7-day exposure cycle. Histopathologic, hematologic, and serum enzyme studies followed necropsy of all mice. There was no mortality of mice exposed for up to 90 days under any condition. Thymus and spleen weights relative to body weight were increased after 4 weeks of exposure by inhalation but not after 8 or 12 weeks of exposure. alpha-, beta-, and delta- Benzenehexachlorides , pentachlorobenzene, and hexachlorobenzene were detected in liver tissue from these animals. Mice exposed to 5- to 10-fold elevated concentration of volatiles had increased body and relative kidney weights. There was no chemically induced lesion in any animal exposed only to the volatile soil contaminants. Mice exposed by direct contact with the soil without elevated volatile exposure had increased body (10%) and relative liver weights (169%). Centrolobular hepatocyte hypertrophy, which involved 40 to 70% of the lobules, was observed in all mice in this group.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6724196

  4. EXPOSURE ASSESSMENT AND FUTURE DIRECTIONS IN EXPOSURE SCIENCE

    EPA Science Inventory

    Exposure is the contact between a stressor and a human or ecological receptor. Risk analysis step in which receptor interaction with the exposure stressor of concern is evaluated. To assess exposure to a particular stressor we need to know - Properties of the stressor; Sources, p...

  5. Deriving site-specific clean-up criteria to protect ecological receptors (plants and soil invertebrates) exposed to metal or metalloid soil contaminants via the direct contact exposure pathway

    PubMed Central

    Checkai, Ron; Van Genderen, Eric; Sousa, José Paulo; Stephenson, Gladys; Smolders, Erik

    2014-01-01

    Soil contaminant concentration limits for the protection of terrestrial plants and soil invertebrates are commonly based on thresholds derived using data from laboratory ecotoxicity tests. A comprehensive assessment has been made for the derivation of ecological soil screening levels (Eco-SSL) in the United States; however, these limits are conservative because of their focus on high bioavailability scenarios. Here, we explain and evaluate approaches to soil limit derivation taken by 4 jurisdictions, 2 of which allow for correction of data for factors affecting bioavailability among soils, and between spiked and field-contaminated soils (Registration Evaluation Authorisation and Restriction of Chemicals [REACH] Regulation, European Union [EU], and the National Environment Protection Council [NEPC], Australia). Scientifically advanced features from these methods have been integrated into a newly developed method for deriving soil clean-up values (SCVs) within the context of site-specific baseline ecological risk assessment. Resulting site-specific SCVs that account for bioavailability may permit a greater residual concentration in soil when compared to generic screening limit concentrations (e.g., Eco-SSL), while still affording acceptable protection. Two choices for selecting the level of protection are compared (i.e., allowing higher effect levels per species, or allowing a higher percentile of species that are potentially unprotected). Implementation of this new method is presented for the jurisdiction of the United States, with a focus on metal and metalloid contaminants; however, the new method can be used in any jurisdiction. A case study for molybdate shows the large effect of bioavailability corrections and smaller effects of protection level choices when deriving SCVs. Integr Environ Assess Manag 2014;10:346–357. PMID:24470189

  6. DIRECT DELAYED RESPONSE PROJECT: SOIL CHARACTERIZATION

    EPA Science Inventory

    A large amount of soil characterization data has been collected as a component of the Direct/Delayed Response Project (DDRP) in the acid rain Aquatic Effects Research Program. n interlaboratory comparison study was undertaken to identify the ability of this data to that obtained ...

  7. Soil quality assessment in long-term direct seed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers in the Pacific Northwest are adopting direct seed farming to reduce soil erosion, improve soil quality and increase water infiltration. Some direct seed producers are concerned with reaching the yield and profit potential expected with long-term direct seed, and this may be due to soil st...

  8. Pesticide Uptake Across the Amphibian Dermis Through Soil and Overspray Exposures.

    PubMed

    Van Meter, Robin J; Glinski, Donna A; Henderson, W Matthew; Garrison, A Wayne; Cyterski, Mike; Purucker, S Thomas

    2015-11-01

    For terrestrial amphibians, accumulation of pesticides through dermal contact is a primary route of exposure in agricultural landscapes and may be contributing to widespread amphibian declines. To show pesticide transfer across the amphibian dermis at permitted label application rates, our study was designed to measure pesticide body burdens after two simulated exposure scenarios. We compared direct exposures, where amphibians were present when spraying occurred, to indirect exposures, where amphibians were exposed to soils after pesticide application. During summer 2012, we reared barking (Hyla gratiosa) and green treefrogs (H. cinerea) through 60-90 days post-metamorphosis at a United States Environmental Protection Agency research laboratory. We tested exposure for 8 h to five pesticide active ingredients (imidacloprid, atrazine, triadimefon, fipronil, or pendimethalin) in glass aquaria lined with soil in the laboratory. We quantified total pesticide body burden and soil concentrations using liquid chromatography-mass spectrometry. All individuals in both treatments had measurable body burdens at the end of the study. A randomized block design analysis of variance (n = 18) showed that body burdens (p = 0.03) and bioconcentration factors (BCFs) (p = 0.01) were significantly greater in the direct overspray treatment relative to the indirect soil spray treatment for both species and tested pesticides. BCFs ranged from 0.1 to 1.16 and from 0.013 to 0.78 in the direct and indirect treatments, respectively. Our study shows dermal uptake for multiple pesticides from both direct spray and indirect soil exposures and provides empirical support for the degree to which terrestrial phase amphibians have higher body burdens after overspray pesticide exposure. PMID:26135301

  9. Children's exposure to mercury-contaminated soils: exposure assessment and risk characterization.

    PubMed

    Guney, Mert; Welfringer, Bruno; de Repentigny, Carl; Zagury, Gerald J

    2013-08-01

    Exposure to mercury (Hg)-contaminated soils may pose a health risk to children by way of oral, dermal, and inhalatory pathways. However, risk characterization studies, including contaminant bioaccessibility with child-specific exposure parameters and scenarios, are lacking. The objectives of this study were (1) to assess children's Hg exposure using characterization and oral bioaccessibility data from Hg-contaminated soils characterized in previous studies (n = 8); and (2) to characterize probabilistic risk in terms of hazard index (HI) considering ingestion, dermal, and inhalation pathways. Total Hg concentrations in soils ranged from 2.61 to 1.15 × 10(4) mg kg(-1). For moderately contaminated soils (S1-S5: Hg ≤ 12.15 mg kg(-1)), low oral bioaccessibility values (1.5-7.5 %) lead to HI < 1 in all scenarios. However, exposure to highly contaminated soils (S6-S8) may pose serious risks to children under normal exposure (HI 0.89-66.5) and soil-pica behaviour scenarios (HI up to 131). All three pathways significantly contributed to the risk. Using total Hg concentrations in calculations (assuming 100 % bioavailability) instead of considering Hg bioavailability leads to risk overestimation. Further research on oral, inhalatory, and dermal bioavailability of Hg, as well as child play behaviour, is recommended to obtain more accurate risk estimates. PMID:23546335

  10. DEPTH DEPENDENCE OF DIRECT AND INDIRECT PHOTOLYSIS ON SOIL SURFACES

    EPA Science Inventory

    The photolysis depth of direct and indirect photolysis in soils was determined with use of two agrochemicals. he denitroaniline herbicide flumetralin and a dialkyl thioether organophosphorus insecticide disulfoton were homogeneously applied to four soils and irradiated. lumetrali...

  11. Soil is an important pathway of human lead exposure.

    PubMed Central

    Mielke, H W; Reagan, P L

    1998-01-01

    This review shows the equal or greater importance of leaded gasoline-contaminated dust compared to lead-based paint to the child lead problem, and that soil lead, resulting from leaded gasoline and pulverized lead-based paint, is at least or more important than lead-based paint (intact and not pulverized) as a pathway of human lead exposure. Because lead-based paint is a high-dose source, the biologically relevant dosage is similar to lead in soil. Both lead-based paint and soil lead are associated with severe lead poisoning. Leaded gasoline and lead in food, but not lead-based paint, are strongly associated with population blood lead levels in both young children and adults. Soil lead and house dust, but not lead-based paint, are associated with population blood lead levels in children. Most soil lead and house dust are associated with leaded gasoline. Lead-based paint dust is associated with cases of renovation of either exterior or interior environments in which the paint was pulverized. Based upon the limited data to date, abatement of soil lead is more effective than abatement of lead-based paint in reducing blood lead levels of young children. About equal numbers of children under 7 years of age are exposed to soil lead and lead-based paint. Seasonality studies point to soil lead as the main source of population blood lead levels. Soil lead is a greater risk factor than lead-based paint to children engaged in hand-to-mouth and pica behavior. In summary, soil lead is important for addressing the population of children at risk of lead poisoning. When soil lead is acknowledged by regulators and the public health community as an important pathway of human lead exposure, then more effective opportunities for improving primary lead prevention can become a reality. Images Figure 1 PMID:9539015

  12. External exposure to radionuclides in air, water, and soil

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.

    1996-05-01

    Federal Guidance Report No. 12 tabulates dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil. The dose coefficients are intended for use by Federal Agencies in calculating the dose equivalent to organs and tissues of the body.

  13. Evaluation of Exposure to Arsenic in Residential Soil

    SciTech Connect

    Tsuji, Joyce S.; Van Kerkhove, Maria D.; Kaetzel, Rhonda; Scrafford, Carolyn; Mink, Pamela; Barraj, Leila M.; Crecelius, Eric A.; Goodman, Michael

    2005-12-01

    In response to concerns regarding arsenic in soil from a pesticide manufacturing plant, we conducted a biomonitoring study on children younger than 7 years of age, the age category of children most exposed to soil. Urine samples from 77 children (47% participation rate) were analyzed for total arsenic and arsenic species related to ingestion of inorganic arsenic. Older individuals also provided urine (n = 362) and toenail (n = 67) samples. Speciated urinary arsenic levels were similar between children (geometric mean, geometric SD, and range: 4.0, 2.2, and 0.89?17.7 ?g/L, respectively) and older participants (3.8, 1.9, 0.91?19.9 ?g/L) and consistent with unexposed populations. Toenail samples were < 1 mg/kg. Correlations between speciated urinary arsenic and arsenic in soil (r = 0.137, p = 0.39; n = 41) or house dust (r = 0.049, p = 0.73; n = 52) were not significant for children. Similarly, questionnaire responses indicating soil exposure were not associated with increased urinary arsenic levels. Relatively low soil arsenic exposure likely precluded quantification of arsenic exposure above background.

  14. Evaluation of Exposure to Arsenic in Residential Soil

    PubMed Central

    Tsuji, Joyce S.; Van Kerkhove, Maria D.; Kaetzel, Rhonda S.; Scrafford, Carolyn G.; Mink, Pamela J.; Barraj, Leila M.; Crecelius, Eric A.; Goodman, Michael

    2005-01-01

    In response to concerns regarding arsenic in soil from a pesticide manufacturing plant, we conducted a biomonitoring study on children younger than 7 years of age, the age category of children most exposed to soil. Urine samples from 77 children (47% participation rate) were analyzed for total arsenic and arsenic species related to ingestion of inorganic arsenic. Older individuals also provided urine (n = 362) and toenail (n = 67) samples. Speciated urinary arsenic levels were similar between children (geometric mean, geometric SD, and range: 4.0, 2.2, and 0.89–17.7 μg/L, respectively) and older participants (3.8, 1.9, 0.91–19.9 μg/L) and consistent with unexposed populations. Toenail samples were < 1 mg/kg. Correlations between speciated urinary arsenic and arsenic in soil (r = 0.137, p = 0.39; n = 41) or house dust (r = 0.049, p = 0.73; n = 52) were not significant for children. Similarly, questionnaire responses indicating soil exposure were not associated with increased urinary arsenic levels. Relatively low soil arsenic exposure likely precluded quantification of arsenic exposure above background. PMID:16330356

  15. Human exposure to soil contaminants in subarctic Ontario, Canada

    PubMed Central

    Reyes, Ellen Stephanie; Liberda, Eric Nicholas; Tsuji, Leonard James S.

    2015-01-01

    Background Chemical contaminants in the Canadian subarctic present a health risk with exposures primarily occurring via the food consumption. Objective Characterization of soil contaminants is needed in northern Canada due to increased gardening and agricultural food security initiatives and the presence of known point sources of pollution. Design A field study was conducted in the western James Bay Region of Ontario, Canada, to examine the concentrations of polychlorinated biphenyls, dichlorodiphenyltrichloroethane and its metabolites (ΣDDT), other organochlorines, and metals/metalloids in potentially contaminated agriculture sites. Methods Exposure pathways were assessed by comparing the estimated daily intake to acceptable daily intake values. Ninety soil samples were collected at random (grid sampling) from 3 plots (A, B, and C) in Fort Albany (on the mainland), subarctic Ontario, Canada. The contaminated-soil samples were analysed by gas chromatography with an electron capture detector or inductively coupled plasma mass spectrometer. Results The range of ΣDDT in 90 soil samples was below the limit of detection to 4.19 mg/kg. From the 3 soil plots analysed, Plot A had the highest ΣDDT mean concentration of 1.12 mg/kg, followed by Plot B and Plot C which had 0.09 and 0.01 mg/kg, respectively. Concentrations of other organic contaminants and metals in the soil samples were below the limit of detection or found in low concentrations in all plots and did not present a human health risk. Conclusion Exposure analyses showed that the human risk was below regulatory thresholds. However, the ΣDDT concentration in Plot A exceeded soil guidelines set out by the Canadian Council of Ministers of the Environment of 0.7 mg/kg, and thus the land should not be used for agricultural or recreational purposes. Both Plots B and C were below threshold limits, and this land can be used for agricultural purposes. PMID:26025557

  16. Soil ecotoxicology: state of the art and future directions

    PubMed Central

    van Gestel, Cornelis A.M.

    2012-01-01

    Abstract Developments in soil ecotoxicology started with observations on pesticide effects on soil invertebrates in the 1960s. To support the risk assessment of chemicals, in the 1980s and 1990s development of toxicity tests was the main issue, including single species tests and also more realistic test systems like model ecosystems and field tests focusing on structural and functional endpoints. In the mean time, awareness grew about issues like bioavailability and routes of exposure, while biochemical endpoints (biomarkers) were proposed as sensitive and potential early-warning tools. In recent years, interactions between different chemicals (mixture toxicity) and between chemical and other stressors attracted scientific interest. With the development of molecular biology, omics tools are gaining increasing interest, while the ecological relevance of exposure and effects is translating into concepts like (chemical) stress ecology, ecological vulnerability and trait-based approaches. This contribution addresses historical developments and focuses on current issues in soil ecotoxicology. It is concluded that soil ecotoxicological risk assessment would benefit from extending the available battery of toxicity tests by including e.g. isopods, by paying more attention to exposure, bioavailability and toxicokinetics, and by developing more insight into the ecology of soil organisms to support better understanding of exposure and long-term consequences of chemical exposure at the individual, population and community level. Ecotoxicogenomics tools may also be helpful in this, but will require considerable further research before they can be applied in the practice of soil ecotoxicological risk assessment. PMID:22536114

  17. Direct Cellular Lysis/Protein Extraction Protocol for Soil Metaproteomics

    SciTech Connect

    Chourey, Karuna; Jansson, Janet; Verberkmoes, Nathan C; Shah, Manesh B; Chavarria, Krystle L.; Tom, Lauren M; Brodie, Eoin L.; Hettich, Robert {Bob} L

    2010-01-01

    We present a novel direct protocol for deep proteome characterization of microorganisms in soil. The method employs thermally assisted detergent-based cellular lysis (SDS) of soil samples, followed by TCA precipitation for proteome extraction/cleanup prior to liquid chromatography-mass spectrometric characterization. This approach was developed and optimized using different soils inoculated with genome-sequenced bacteria (Gram-negative Pseudomonas putida or Gram-positive Arthrobacter chlorophenolicus). Direct soil protein extraction was compared to protein extraction from cells isolated from the soil matrix prior to lysis (indirect method). Each approach resulted in identification of greater than 500 unique proteins, with a wide range in molecular mass and functional categories. To our knowledge, this SDS-TCA approach enables the deepest proteome characterizations of microbes in soil to date, without significant biases in protein size, localization, or functional category compared to pure cultures. This protocol should provide a powerful tool for ecological studies of soil microbial communities.

  18. Risk of classic Kaposi sarcoma with residential exposure to volcanic and related soils in Sicily

    PubMed Central

    Pelser, Colleen; Dazzi, Carmelo; Graubard, Barry I.; Lauria, Carmela; Vitale, Francesco; Goedert, James J.

    2009-01-01

    Purpose Before AIDS, endemic (African) Kaposi sarcoma (KS) was noted to occur in volcanic areas and was postulated to result from dirt chronically embedded in the skin of the lower extremities. The primary cause of all KS types is KS-associated herpesvirus (KSHV) infection, but co-factors contribute to the neoplasia. We investigated whether residential exposure volcanic or related soils was associated with the risk of classic Kaposi sarcoma (cKS) in Sicily. Methods Risk of incident cKS (n=141) compared to population-based KSHV seropositive controls (n=123) was estimated for residential exposure to four types of soil, categorized with maps from the European Soil Database and direct surveying. Questionnaire data provided covariates. Results Residents in communities high in luvisols were approximately 2.7-times more likely to have cKS than those in communities with no luvisols. Risk was not specific for cKS on the limbs, but it was elevated approximately 4–5-fold with frequent bathing or tap water drinking in high luvisols communities. Risk was unrelated to communities high in andosols, tephra, or clay soils. Conclusions Iron and alumino-silicate clay, major components of luvisols, may increase cKS risk, but formal investigation and consideration of other soil types and exposures are needed. PMID:19576540

  19. Preserve CRP Soil Quality by Direct Seeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As growers approach the end of Conservation Reserve Program (CRP) contracts and return lands to crop production, they are faced with the decision of how to best manage these lands. Direct seed may be a viable option in returning CRP lands to crop production to avoid some of the issues normally assoc...

  20. Remote determination of exposure degree and iron concentration of lunar soils using VIS-NIR spectroscopic methods

    NASA Technical Reports Server (NTRS)

    Fischer, Erich M.; Pieters, Carle M.

    1994-01-01

    On the Moon, space weathering processes such as micrometeorite bombardment alter the optical properties of lunar soils. As a consequence, lunar soil optical properties are a function not only of composition, but of degree of exposure on the lunar surface as well. In order to accurately assess the compositional properties of the lunar surface using remotely acquired visible and near-infrared spectroscopic data, it is thus necessary either (1) to compare optical properties only of soils characterized by similar degrees of exposure or (2) to otherwise normalize or remove the optical effects due to exposure. Laboratory spectroscopic data for lunar soils are used to develop and test remote spectrocopic methods for determining degree of exposure and for distinguishing between the optical effects due to exposure and those due to composition. A method employing a ratio between reflectances within and outside of the 1 micrometer Fe(2+) crystal field absorption band was developed for remotely identifying highland soils that have reached a steady-state maturity. The relative optical properties of these soils are a function solely of composition and as such can be directly compared. Spectroscopic techniques for accurate quantitative determination of iron content for lunar highland soils are investigated as well. It is shown that approximations of the 1 micrometer Fe(2+) absorption band depth using few to several channel multispectral data or spectroscopic data of inadequate spectral range cannot be used with confidence for compositional analysis. However, band depth measurements derived from continuum-removed high spectral resolution data can be used to calculate the weight percent FeO and relative proportion of iron-bearing silicates in mature lunar highland and mare/highland mixture soils. A preliminary effort to calibrate telescopic band depth to laboratory soil measurements is described.

  1. First direct exposure to lunar material for Crew Reception personnel

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The first direct exposure to lunar material for Crew Reception personnel probably happened late Friday, July 25, 1969. Terry Slezak (displaying moon dust on his left hand fingers), Manned Spacecraft Center (MSC) photographic technician, was removing film magazines from the first of two containers when the incident occurred. As he removed the plastic seal from Magazine S, one of the 70mm magazines taken during Apollo 11 Extravehicular Activity (EVA), it was apparent that the exterior of the cassette displayed traces of a black powdery substance. Apollo 11 Commander Neil Armstrong reported during the mission that he had retrieved a 70mm cassette which had dropped to the lunar surface.

  2. Direct Extraction and Amplification of DNA from Soil.

    ERIC Educational Resources Information Center

    Trevors, Jack T.; Leung, K.

    1998-01-01

    Presents an exercise that describes the direct extraction and purification of DNA from a small soil sample. Also discusses the subsequent amplification of a 343-bp Tn7 transposate A gene fragment (tnsA) from a strain of Pseudomonas aureofaciens 3732RNL11. Contains 21 references. (DDR)

  3. Effects of Direct and Indirect Exposure of Insecticides to Garden Symphylan (Symphyla: Scutigerellidae) in Laboratory Bioassays.

    PubMed

    Joseph, Shimat V

    2015-12-01

    The garden symphylan, Scutigerella immaculata Newport, is a serious soil pest whose root feeding affects yield and survival of several high valued crops in the California's central coast. Because organophosphate insecticides, widely used for S. immaculata control, are rigorously regulated and little is known about the efficacy of alternate insecticides, laboratory bioassays were conducted to determine insecticide efficacy through repellency and lethality. To determine indirect repellency (noncontact) of insecticides, choice assays were conducted where five S. immaculata were introduced into the arena to choose between insecticide-treated and untreated wells whereas, in direct repellency (contact) assays, three insecticide-treated 1-cm-diameter discs were pasted into the arena and the number of visits, time spent per visitation, and number of long-duration (>10 s) stays of five S. immaculata were quantified. To determine efficacy through direct mortality, number of S. immaculata died after 72 h were determined by introducing 10 S. immaculata to insecticide-treated soil assays. In indirect exposure bioassays, seven (clothianidin, oxamyl, zeta-cypermethrin, chlorpyrifos, ethoprop, azadirachtin, and a combination of beta-cyfluthrin and imidacloprid) out of 14 insecticides tested elicited repellency to S. immaculata. Of six insecticides tested in the direct exposure assays, only tolfenpyrad elicited contact repellency. In soil assays, after 72 h of introduction, bifenthrin, oxamyl, clothianidin, zeta-cypermethrin, and tolfenpyrad caused 100, 95, 80, 44, and 44% S. immaculata mortality, respectively, which was significantly greater than distilled water and four other insecticides. The implications of these results on S. immaculata management in the California's central coast are discussed. PMID:26470373

  4. Experimental evidence for direct sesquiterpene emission from soils

    NASA Astrophysics Data System (ADS)

    HorváTh, Eszter; Hoffer, AndráS.; SebőK, Flóra; Dobolyi, Csaba; Szoboszlay, SáNdor; Kriszt, BaláZs; GelencséR, AndráS.

    2012-08-01

    The biogenic organic precursors which are of relevance in secondary organic aerosol formation are primarily isoprene, monoterpenes, sesquiterpenes (SQTs) and their derivatives. Atmospheric volatile organic compound inventories consider plant emissions as the exclusive sources of natural secondary organic aerosol precursors. Very recently we have shown in pure culture experiments that abundant soil fungal strains are capable of producing significant emission fluxes of SQTs and have implied that soils might be globally important SQT emission sources. In the present follow-up study we determined sesquiterpene emission fluxes in the laboratory directly from unperturbed soil samples and from selected soil samples with the top litter layer removed. We also characterized basic soil parameters and native fungal strains in the samples, and quantified ergosterol as a proxy of bulk fungal biomass. The measured SQT emission fluxes (6-1980 ng m-2 h-1; median 109 ng m-2 h-1) were of the same magnitude as inferred from culture experiments confirming that soil biota can be an important sesquiterpene emission source that has to be included in future VOC inventories.

  5. X-ray calibration of Kodak Direct Exposure film

    SciTech Connect

    Brown, D.B.; Burkhalter, P.G.; Rockett, P.D.; Bird, C.R.; Hailey, C.J.; Sullivan, D.

    1985-08-15

    Kodak Direct Exposure film (DEF) has replaced Kodak No-Screen film for use in x-ray diffraction analysis and in autoradiography. DEF is a double-emulsion film which has been found to have improved radio-graphic characteristics over No-Screen. A set of H-D curves has been generated for DEF at five photon energies: 0.930, 1.49, 1.74, 4.51/4.93, and 6.93 keV. The KMSF x-ray calibration facility was utilized to study the absolute sensitivity of this film over its full dynamic range. Physical examination of the film was followed by theoretical modeling, which adequately reproduced the measured curves.

  6. Mapping Soil Salinity with ECa-Directed Soil Sampling: History, Protocols, Guidelines, Applications, and Future Research Trends

    NASA Astrophysics Data System (ADS)

    Corwin, Dennis

    2014-05-01

    Soil salinity is a spatially complex and dynamic property of soil that influences crop yields when the threshold salinity level is exceeded. Mapping soil salinity is necessary for soil classification, reclamation, crop selection, and site-specific irrigation management of salt-affected soils in the arid and semi-arid agricultural regions of the world. Because of its spatial and temporal heterogeneity soil salinity is difficult to map and monitor at field scales. There are various methods for characterizing soil salinity variability, but none of these approaches has been as extensively investigated and is as reliable and cost effective as apparent soil electrical conductivity (ECa) directed soil sampling. Geospatial measurements of ECa are well-suited for characterizing soil salinity spatial distribution because they are reliable, quick, and easy to take with GPS-based mobilized ECa measurement equipment. However, ECa is influenced by a variety of soil properties, which makes the measurement of soil salinity at field scale problematic. It is the goal of this presentation to provide an overview of the field-scale characterization of soil salinity distribution using ECa-directed soil sampling. A historical perspective, protocols and guidelines, strengths and limitations, applications, and future trends are presented for characterizing spatial and temporal variation in soil salinity using ECa-directed soil sampling. Land resource managers, farmers, extension specialists, soil classification specialists, and Natural Resource Conservation Service field staff are the beneficiaries of field-scale maps of soil salinity.

  7. Direct Evidence Linking Soil Organic Matter Development to Microbial Communities

    NASA Astrophysics Data System (ADS)

    Kallenbach, C.; Grandy, S.

    2013-12-01

    Despite increasing recognition of microbial contributions to soil organic matter (SOM) formation there is little experimental evidence linking microbial processes to SOM development and the mechanisms responsible remain unclear. Specifically, if stable SOM is largely comprised of microbial products, we need to better understand the soil conditions that influence microbial biomass production and ultimately its stability. Microbial physiology, such as microbial growth efficiency (MGE) and rate (MGR) have direct influences on microbial biomass production and are highly sensitive to resource quality. Therefore, the importance of resource quality on SOM is not necessarily a function of resistance to decay but the degree to which it optimizes microbial biomass production. While resource quality may have an indirect effect on SOM abundance via its influence on microbial physiology, SOM stabilization of labile microbial products may rely heavily on a soil's capacity to form organo-mineral interactions. To examine the relative importance of soil microbial community function, resource quality and mineralogy on direct microbial contributions to SOM formation and stability, an ongoing 15-mo incubation experiment was set up using artificial, initially C- and microbial-free soils. Soil microcosms were constructed by mixing sand with either kaolinite or montmorillonite clays followed with a natural soil microbial inoculum. For both soil mineral treatments, weekly additions of glucose, cellobiose, or syringol are carried out, with an additional treatment of plant leachate to serve as a reference. This simplified system allows us to determine if, in the absence of plant-derived C, microbial products using simple substrates can result in chemically complex SOM similar to natural soils. Over the course of the incubation, MGE, MGR, microbial activity, and SOM accumulation rates are monitored. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) is used to track the microbial

  8. Consideration of soil properties in assessment of human health risk from exposure to arsenic-enriched soils.

    PubMed

    Datta, Rupali; Sarkar, Dibyendu

    2005-01-01

    Encroachment of residential development on agricultural lands in the United States where arsenical pesticides were extensively used prior to the 1990s has increased the potential for human exposure to arsenic (As), a group A carcinogen. Soil ingestion by children is a critical issue in assessing health risks from exposure to As-enriched soils. In the absence of a universal "soil model" on As bioavailability, many baseline risk assessment studies use the assumption that all (100%) As present in soil is bioavailable. However, As exists in many geochemical forms as dictated by soil chemical properties. Because As bioavailability is a function of soil speciation, using total soil arsenic values potentially overestimates human health risk, thereby increasing site cleanup expenses. A laboratory incubation study was conducted to estimate in vitro As bioavailability as a function of soil properties in four chemically variant soil types contaminated with sodium arsenite pesticide. Results demonstrate that As speciation in certain soils translates to significant lowering of As bioavailability and hence potential cancer risk. PMID:16637147

  9. Direct Tension Test Using a Plate Specimen in Cohesive Soil

    NASA Astrophysics Data System (ADS)

    Nishimura, Shin-Ichi

    Hydraulic fracturing is probably one of the causes of leakage and collapse in a dam body or foundation. Water pressure develops cracks and this is one of the causes for hydraulic fracturing. It is important to evaluate characteristics of tensile strength in the foundation and embankment material of fill-dam to examine development conditions of the cracks. It is possible to evaluate tensile strength of hard rocks and metals by fixing both ends of the specimen with chucks and making it work directly. However, it is not possible to use the same method for soft material like cohesive soil. Hence direct tensile test was performed in this research by the plate type specimen used for the calculation of energy release rate (J integral). Then the stress distribution in the specimen and the energy release rate were calculated by FEM to examine a form of the specimen useful for the direct tensile test of cohesive soil. Consequently it is considered that tensile strength of cohesive soil can be measured by adjusting height of the specimen and length of the initial crack to a suitable value respectively.

  10. Waterpipe Tobacco and Cigarette Smoking Direct Comparison of Toxicant Exposure

    PubMed Central

    Eissenberg, Thomas; Shihadeh, Alan

    2009-01-01

    Background Waterpipe (hookah, shisha) tobacco smoking has spread worldwide. Many waterpipe smokers believe that, relative to cigarettes, waterpipes are associated with lower smoke toxicant levels and fewer health risks. For physicians to address these beliefs credibly, waterpipe and cigarette must be compared directly. Purpose The purpose of this study is to provide the first controlled, direct laboratory comparison of the toxicant exposure associated with waterpipe tobacco and cigarette smoking Methods Participants (N=31; mean=21.4 years, SD=2.3) reporting monthly waterpipe use (mean 5.2 uses/month, SD=4.0) and weekly cigarette smoking (mean= 9.9 cigarettes/day, SD=6.4) completed a crossover study in which they each smoked a waterpipe for a maximum of 45 minutes or a single cigarette. Outcomes included expired air carbon monoxide (CO) 5 minutes after session’s end, and blood carboxyhemoglobin (COHb), plasma nicotine, heart rate, and puff topography. Data were collected in 2008–2009 and analyzed in 2009. Results CO increased, on average, by 23.9 ppm for waterpipe (SD=19.8) and 2.7 ppm for cigarette (SD=1.8) while peak waterpipe COHb levels (mean=3.9%, SD=2.5) were three times those observed for the cigarette (mean=1.3%, SD=0.5; Ps<0.001). Peak nicotine levels did not differ (mean ng/ml waterpipe=10.2, SD=7.0; cigarette=10.6, SD=7.7). Significant heart rate increases relative to pre-smoking were observed 5, 10, 15, 20, 25, and 35 minutes during the cigarette session and at every 5-minute interval during the waterpipe session (Ps<0.001). Mean total puff volume was 48.6 liters for waterpipe as compared to 1.0 liters for cigarette (P<0.001). Conclusions Relative to a cigarette, waterpipe use is associated with greater CO, similar nicotine, and dramatically more smoke exposure. Physicians should consider advising their patients that waterpipe tobacco smoking exposes them to some of the same toxicants as cigarette smoking and therefore the two tobacco smoking methods

  11. A chain modeling approach to estimate the impact of soil cadmium pollution on human dietary exposure.

    PubMed

    Franz, Eelco; Römkens, Paul; van Raamsdonk, Leo; van der Fels-Klerx, Ine

    2008-12-01

    Cadmium in soil poses a risk for human health, due to its accumulation in food and feed crops. The extent of accumulation depends strongly on soil type and the degree of pollution. The objective of the present study was to develop a predictive model to estimate human dietary cadmium exposure from soil characteristics. This chain model consists of three basic steps: (i) calculation of plant cadmium levels from soil contamination levels and soil characteristics, (ii) calculation of animal transfer from consumption and contamination levels, and (iii) human exposure from both plant and animal products. Six soil scenarios were assessed, reflecting a specific contaminated region and ranging from 0.5 mg/kg of Cd (pH 4.5) to 2.5 mg/kg of Cd (pH 5.5). Cadmium levels in feed crops and vegetables were estimated with regression and mathematical models. Animal exposure and transfer to cattle kidneys, livers, and meat were calculated using a consumption database and a parameterized linear simulation model. Human exposure was estimated by Monte Carlo simulation, using a consumption database. The median human exposure for the different scenarios ranged from 0.24 to 0.98 microg/kg of body weight per day, which is comparable to results obtained from exposure levels based on observed field contamination data. The study shows that a chain model approach from soil contamination to human exposure, including animal exposure and transfer to animal products, can successfully be applied. The model can be used for fast evaluation of dietary cadmium exposure and the identification of risk areas based on soil conditions. PMID:19244905

  12. Assessment of bioaccessibility and exposure risk of arsenic and lead in urban soils of Guangzhou City, China.

    PubMed

    Lu, Ying; Yin, Wei; Huang, Longbin; Zhang, Ganlin; Zhao, Yuguo

    2011-04-01

    Soil ingestion is an important human exposure pathway of heavy metals in urban environments with heavy metal contaminated soils. This study aims to assess potential health risks of heavy metals in soils sampled from an urban environment where high frequency of human exposure may be present. A bioaccessibility test is used, which is an in vitro gastrointestinal (IVG) test of soluble metals under simulated physiological conditions of the human digestion system. Soil samples for assessing the oral bioaccessibility of arsenic (As) and lead (Pb) were collected from a diverse range of different land uses, including urban parks, roadsides, industrial sites and residential areas in Guangzhou City, China. The soil samples contained a wide range of total As (10.2 to 61.0 mg kg(-1)) and Pb (38.4 to 348 mg kg(-1)) concentrations. The bioaccessibility of As and Pb in the soil samples were 11.3 and 39.1% in the stomach phase, and 1.9 and 6.9% in the intestinal phase, respectively. The As and Pb bioaccessibility in the small intestinal phase was significantly lower than those in the gastric phase. Arsenic bioaccessibility was closely influenced by soil pH and organic matter content (r (2) = 0.451, p < 0.01) in the stomach phase, and by organic matter, silt and total As contents (r (2) = 0.604, p < 0.001) in the intestinal phase. The general risk of As and Pb intake for children from incidental ingestion of soils is low, compared to their maximum doses, without causing negative human health effects. The exposure risk of Pb in the soils ranked in the order of: industrial area/urban parks > residential area/road side. Although the risk of heavy metal exposure from direct ingestion of urban soils is relatively low, the risk of inhalation of fine soil particulates in the air remains to be evaluated. PMID:20524051

  13. Limited recovery of soil microbial activity after transient exposure to gasoline vapors.

    PubMed

    Modrzyński, Jakub J; Christensen, Jan H; Mayer, Philipp; Brandt, Kristian K

    2016-09-01

    During gasoline spills complex mixtures of toxic volatile organic compounds (VOCs) are released to terrestrial environments. Gasoline VOCs exert baseline toxicity (narcosis) and may thus broadly affect soil biota. We assessed the functional resilience (i.e. resistance and recovery of microbial functions) in soil microbial communities transiently exposed to gasoline vapors by passive dosing via headspace for 40 days followed by a recovery phase of 84 days. Chemical exposure was characterized with GC-MS, whereas microbial activity was monitored as soil respiration (CO2 release) and soil bacterial growth ([(3)H]leucine incorporation). Microbial activity was strongly stimulated and inhibited at low and high exposure levels, respectively. Microbial growth efficiency decreased with increasing exposure, but rebounded during the recovery phase for low-dose treatments. Although benzene, toluene, ethylbenzene and xylene (BTEX) concentrations decreased by 83-97% during the recovery phase, microbial activity in high-dose treatments did not recover and numbers of viable bacteria were 3-4 orders of magnitude lower than in control soil. Re-inoculation with active soil microorganisms failed to restore microbial activity indicating residual soil toxicity, which could not be attributed to BTEX, but rather to mixture toxicity of more persistent gasoline constituents or degradation products. Our results indicate a limited potential for functional recovery of soil microbial communities after transient exposure to high, but environmentally relevant, levels of gasoline VOCs which therefore may compromise ecosystem services provided by microorganisms even after extensive soil VOC dissipation. PMID:27376993

  14. Analysis of retinoids by direct exposure probe mass spectrometry.

    PubMed

    Papa, V M; Hupert, J; Friedman, H; Ng, P S; Robbins, E F; Mobarhan, S

    1988-10-01

    Recently, our laboratory has investigated the depletion of Vitamin A and its metabolites in experimental animals. High Pressure Liquid Chromatography (HPLC) was used to measure retinal oxidase activity by monitoring the conversion of retinaldehyde (RALD) to retinoic acid (ROIC). In order to obtain more information about these compounds, a Direct Exposure Probe mass spectrometric method was developed to confirm the presence of ROIC and RALD in HPLC peaks. A rapid negative ion chemical ionization (NICI) method using ammonia as reagent gas was developed to detect the presence of ROIC and RALD with picogram sensitivity. The ROIC and RALD peaks were collected from HPLC, extracted with hexane, evaporated under nitrogen and reconstituted in ethanol before placing onto a rhenium filament with current programmed from 0-1.3 A at 50 mA/sec. The instrument employed was a Finnigan 4510 operated in the NICI mode and scanned from m/z 100-650 with a source temperature of 80 C. Other parameters were electron energy 140 eV and filament current at 0.25 mA. Prominent ions were generated at m/z 284 and m/z 300 for RALD and ROIC which were subsequently monitored in the selected ion monitoring mode. In summary, we have developed a rapid retinoid identification method (2.5 minutes) which is more sensitive (pg vs ng) than HPLC and does not require elaborate sample preparation or derivitization. This method can be used as an important adjunct to HPLC enzyme studies. PMID:3242687

  15. Using growth-based methods to determine direct effects of salinity on soil microbial communities

    NASA Astrophysics Data System (ADS)

    Rath, Kristin; Rousk, Johannes

    2015-04-01

    Soil salinization is a widespread agricultural problem and increasing salt concentrations in soils have been found to be correlated with decreased microbial activity. A central challenge in microbial ecology is to link environmental factors, such as salinity, to responses in the soil microbial community. That is, it can be difficult to distinguish direct from indirect effects. In order to determine direct salinity effects on the community we employed the ecotoxicological concept of Pollution-Induced Community Tolerance (PICT). This concept is built on the assumption that if salinity had an ecologically relevant effect on the community, it should have selected for more tolerant species and strains, resulting in an overall higher community tolerance to salt in communities from saline soils. Growth-based measures, such as the 3H-leucine incorporation into bacterial protein , provide sensitive tools to estimate community tolerance. They can also provide high temporal resolution in tracking changes in tolerance over time. In our study we used growth-based methods to investigate: i) at what levels of salt exposure and over which time scales salt tolerance can be induced in a non-saline soil, and (ii) if communities from high salinity sites have higher tolerance to salt exposure along natural salinity gradients. In the first part of the study, we exposed a non-saline soil to a range of salinities and monitored the development of community tolerance over time. We found that community tolerance to intermediate salinities up to around 30 mg NaCl per g soil can be induced at relatively short time scales of a few days, providing evidence that microbial communities can adapt rapidly to changes in environmental conditions. In the second part of the study we used soil samples originating from natural salinity gradients encompassing a wide range of salinity levels, with electrical conductivities ranging from 0.1 dS/m to >10 dS/m. We assessed community tolerance to salt by

  16. The development of applied action levels for soil contact: a scenario for the exposure of humans to soil in a residential setting.

    PubMed Central

    Sedman, R M

    1989-01-01

    The California Site Mitigation Decision Tree Manual, 1985, was developed by the California Department of Health Services to provide a detailed technical basis for managing uncontrolled hazardous waste sites. The Decision Tree describes a process that relies on criteria, Applied Action Levels (AALs) to evaluate and, if necessary, mitigate the impact of uncontrolled hazardous waste sites on the public health and the environment. AALs are developed for individual substances, species, and media of exposure. AALs have been routinely developed for the media of air and water; however, an approach for developing AALs for soil contact was lacking. Given that the air pathway for soil contact is addressed in AALs for air, two routes of exposure, ingestion and dermal contact, are addressed in developing AALs for soil contact. The approach assumes a lifetime of exposure to soil in a residential setting. Age-related changes in exposure are included in the scenario. Exposure to soil due to ingestion and dermal contact are quantitated independently and then integrated in the final exposure scenario. A mass balance approach using four elements is employed to quantitate soil ingestion for a young child. Changes in soil ingestion with age are based on age-related changes in blood lead concentration and mouthing behavior. Dermal exposure to soil was determined from studies that reported skin soil load and from estimates of exposed skin surface area. Age-related changes in the dermal exposure to soil are also based on changes with age of blood lead concentration and mouthing behavior. The estimates of exposure to soil due to ingestion and dermal contact are integrated, and an approach for developing AALs is advanced. AALs are derived by allocating the Maximum Exposure Level as described in the Decision Tree to the average daily exposure to soil. Toxicokinetic considerations for the two routes of exposure must be included in deriving AALs for the soil medium of exposure. PMID:2651104

  17. Direct modification of bioactive phenothiazines by exposure to laser radiation.

    PubMed

    Pascu, Mihail-Lucian; Nastasa, Viorel; Smarandache, Adriana; Militaru, Andra; Martins, Ana; Viveiros, Miguel; Boni, Mihai; Andrei, Ionut Relu; Pascu, Alexandru; Staicu, Angela; Molnar, Joseph; Fanning, Seamus; Amaral, Leonard

    2011-05-01

    Whereas exposure of combinations of a phenothiazine and bacterium to incoherent UV increases the activity of the phenothiazine, exposure of the phenothiazine alone does not yield an increase of its activity. Because the laser beam energy is greater than that produced by the incoherent UV sources, exposure of phenothiazines to specific lasers may yield molecules with altered activities over that of the unexposed parent. Chlorpromazine, thioridazine and promethazine active against bacteria were exposed to two distinct lasers for varying periods of time. Absorption and fluorescence spectra were conducted prior to and post-exposure and the products of laser exposure evaluated for activity against a Staphylococcus aureus ATCC strain via a disk susceptibility assay. Exposure to lasers alters the absorption/fluorescence spectra of the phenothiazines; reduces the activity of thioridazine against the test bacterium; produces a highly active chlorpromazine compound against the test organism. Exposure of phenothiazines to lasers alters their structure that results in altered activity against a bacterium. This is the first report that lasers can alter the physico-chemico characteristics to the extent that altered bioactivity results. Exposure to lasers is expected to yield compounds that are difficult to make via chemical manipulation methods. A survey of selected patents of interest, even co-lateral for the subject of this article is shortly made. PMID:21517738

  18. Population exposure from the fuel cycle: Review and future direction

    SciTech Connect

    Richmond, C.R.

    1987-01-01

    The legacy of radiation exposures confronting man arises from two historical sources of energy, the sun and radioactive decay. Contemporary man continues to be dependent on these two energy sources, which include the nuclear fuel cycle. Radiation exposures from all energy sources should be examined, with particular emphasis on the nuclear fuel cycle, incidents such as Chernobyl and Three Mile Island. In addition to risk estimation, concepts such as de minimis, life shortening as a measure of risk, and competing risks as projected into the future must be considered in placing radiation exposures in perspective. The utility of these concepts is in characterizing population exposures for decision makers in a manner that the public may judge acceptable. All these viewpoints are essential in the evaluation of population exposure from the nuclear fuel cycle.

  19. Reduction in the earthworm metabolomic response after phenanthrene exposure in soils with high soil organic carbon content.

    PubMed

    McKelvie, Jennifer R; Whitfield Åslund, Melissa; Celejewski, Magda A; Simpson, André J; Simpson, Myrna J

    2013-04-01

    We evaluated the correlation between soil organic carbon (OC) content and metabolic responses of Eisenia fetida earthworms after exposure to phenanthrene (58 ± 3 mg/kg) spiked into seven artificial soils with OC contents ranging from 1 to 27% OC. Principal component analysis of (1)H nuclear magnetic resonance (NMR) spectra of aqueous extracts identified statistically significant differences in the metabolic profiles of control and phenanthrene-exposed E. fetida in the 1% OC soil only. Partial least squares analysis identified a metabolic response in the four soils with OC values ≤11% which was well correlated to estimated phenanthrene porewater concentrations. The results suggest that the higher sorption capability of high OC soils decreased the bioavailability of phenanthrene and the subsequent metabolic response of E. fetida. PMID:23337355

  20. The effect of ultralow-dose antibiotics exposure on soil nitrate and N2O flux

    NASA Astrophysics Data System (ADS)

    Devries, Stephanie L.; Loving, Madeline; Li, Xiqing; Zhang, Pengfei

    2015-11-01

    Exposure to sub-inhibitory concentrations of antibiotics has been shown to alter the metabolic activity of micro-organisms, but the impact on soil denitrification and N2O production has rarely been reported. In this study, incubation and column transport experiments were conducted on soils exposed to as many as four antibiotics in the ng·kg-1 range (several orders of magnitude below typical exposure rates) to evaluate the impact of ultralow dose exposure on net nitrate losses and soil N2O flux over time. Under anaerobic incubation conditions, three antibiotics produced statistically significant dose response curves in which denitrification was stimulated at some doses and inhibited at others. Sulfamethoxazole in particular had a stimulatory effect at ultralow doses, an effect also evidenced by a near 17% increase in nitrate removal during column transport. Narasin also showed evidence of stimulating denitrification in anaerobic soils within 3 days of exposure, which is concurrent to a statistically significant increase in N2O flux measured over moist soils exposed to similar doses. The observation that even ultralow levels of residual antibiotics may significantly alter the biogeochemical cycle of nitrogen in soil raises a number of concerns pertaining to agriculture, management of nitrogen pollution, and climate change, and warrants additional investigations.

  1. The effect of ultralow-dose antibiotics exposure on soil nitrate and N2O flux

    PubMed Central

    DeVries, Stephanie L.; Loving, Madeline; Li, Xiqing; Zhang, Pengfei

    2015-01-01

    Exposure to sub-inhibitory concentrations of antibiotics has been shown to alter the metabolic activity of micro-organisms, but the impact on soil denitrification and N2O production has rarely been reported. In this study, incubation and column transport experiments were conducted on soils exposed to as many as four antibiotics in the ng·kg−1 range (several orders of magnitude below typical exposure rates) to evaluate the impact of ultralow dose exposure on net nitrate losses and soil N2O flux over time. Under anaerobic incubation conditions, three antibiotics produced statistically significant dose response curves in which denitrification was stimulated at some doses and inhibited at others. Sulfamethoxazole in particular had a stimulatory effect at ultralow doses, an effect also evidenced by a near 17% increase in nitrate removal during column transport. Narasin also showed evidence of stimulating denitrification in anaerobic soils within 3 days of exposure, which is concurrent to a statistically significant increase in N2O flux measured over moist soils exposed to similar doses. The observation that even ultralow levels of residual antibiotics may significantly alter the biogeochemical cycle of nitrogen in soil raises a number of concerns pertaining to agriculture, management of nitrogen pollution, and climate change, and warrants additional investigations. PMID:26606964

  2. Measurement of directional thermal infrared emissivity of vegetation and soils

    SciTech Connect

    Norman, J.M.; Balick, L.K.

    1995-10-01

    A new method has been developed for measuring directional thermal emissivity as a function of view angle for plant canopies and soils using two infrared thermometers each sensitive to a different wavelength band. By calibrating the two infrared thermometers to 0.1C consistency, canopy directional emissivity can be estimated with typical errors less than 0.005 in the 8--14 um wavelength band, depending on clarity of the sky and corrections for CO{sub 2} absorption by the atmosphere. A theoretical justification for the method is developed along with an error analysis. Laboratory measurements were used to develop corrections for CO{sub 2}, absorption and a field calibration method is used to obtain the necessary 0.1C consistency for relatively low cost infrared thermometers. The emissivity of alfalfa (LAI=2.5) and corn (LAI=3.2) was near 0.995 and independent of view angle. Individual corn leaves had an emissivity of 0.97. A wheat (LAI=3.0) canopy had an emissivity of 0.985 at nadir and 0.975 at 75 degree view angle. The canopy emissivity values tend to be higher than values in the literature, and are useful for converting infrared thermometer measurements to kinetic temperature and interpreting satellite thermal observations.

  3. A risk assessment of direct and indirect exposure to emissions from a proposed hazardous waste incinerator in Puerto Rico

    SciTech Connect

    Hallinger, K.; Huggins, A.; Warner, L.

    1995-12-31

    An Indirect Exposure Assessment (IEA) was conducted, under USEPA`s RCRA Combustion Strategy, as part of the Part B permitting process for a proposed hazardous waste incinerator. The IEA involved identification of constituents of concern, emissions estimations, air dispersion and deposition modeling, evaluation of site-specific exposure pathways/scenarios, and food chain modeling in order to evaluate potential human health and environmental risks. The COMPDEP model was used to determine ambient ground level concentrations and dry and wet deposition rates of constituents of concern. The air modeling results were input into 50th percentile (Central) and 95th percentile (High-End) exposure scenarios which evaluated direct exposure via inhalation, dermal contact, and soil ingestion pathways, and indirect exposure through the food chain. The indirect pathway analysis considered the accumulation of constituents in plants and animals used as food sources by local inhabitants. Local food consumption data obtained from the Puerto Rico USDA were combined with realistic present-day and future-use exposure scenarios such as residential use, pineapple farming, and subsistence farming to obtain a comprehensive evaluation of risk, Overall risk was calculated using constituent doses and toxicity factors associated with the various routes of exposure. Risk values for each exposure pathway were summed to determine total carcinogenic and non-carcinogenic hazard to exposed individuals. A population risk assessment was also conducted in order to assess potential risks to the population surrounding the facility. Results of the assessment indicated no acute effects from constituents of concern, and a high-end excess lifetime cancer risk of approximately 6 in a million with dioxins (as 2,3,7,8-TCDD) and arsenic dominating the risk estimate.

  4. Protection from radon exposure at home and at work in the directive 2013/59/Euratom.

    PubMed

    Bochicchio, F

    2014-07-01

    In recent years, international organisations involved in radiation protection and public health have produced new guidance, recommendations and requirements aiming better protection from radon exposure. These organisations have often worked in close collaboration in order to facilitate the establishment of harmonised standards. This paper deals with such standards and specifically with the new European Council Directive of 5 December 2013 on basic safety standards for protection against the dangers arising from exposure to ionising radiation (2013/59/Euratom). This new Directive has established a harmonised framework for the protection against ionising radiations, including protection from radon exposure. Requirements for radon in workplace are much more tightening than in previous Directive, and exposures to radon in dwellings are regulated for the first time in a Directive. Radon-related articles of this Directive are presented and discussed in this paper, along with some comparisons with other relevant international standards. PMID:24729590

  5. Calculation of the radiation doses occurring in the human body for inadvertent ingestion of soil and other soil exposure pathways

    NASA Astrophysics Data System (ADS)

    Oner, F.; Okumuolu, N.

    2003-11-01

    We estimate the radiation doses in the human body, in the Gudalore region in India, following the inadvertent ingestion of soil and exposure to other soil pathways by measuring Th-232, U-238, and K-40. We estimate the equivalent dose in eleven different organs and the absorbed dose calculations for the whole body. The annual effective doses are calculated, the lowest is in Kariyasolai at 7.8 x 10(-3) mSv whereas the highest is in Ponnur at 8.9 x 10(-2) mSv. In all regions, the lowest equivalent doses through inadvertent soil ingestion are calculated in the kidney and thyroid whereas the highest doses are in the red marrow and on the bone surface.

  6. Prenatal alcohol and other early childhood adverse exposures: Direct and indirect pathways to adolescent drinking

    PubMed Central

    Cornelius, Marie D.; De Genna, Natacha M.; Goldschmidt, Lidush; Larkby, Cynthia; Day, Nancy L.

    2016-01-01

    We examined direct and indirect pathways between adverse environmental exposures during gestation and childhood and drinking in mid-adolescence. Mothers and their offspring (n = 917 mother/child dyads) were followed prospectively from second trimester to a 16-year follow-up assessment. Interim assessments occurred at delivery, 6, 10, and 14 years. Adverse environmental factors included gestational exposures to alcohol, tobacco, and marijuana, exposures to childhood maltreatment and violence, maternal psychological symptoms, parenting practices, economic and home environments, and demographic characteristics of the mother and child. Indirect effects of early child behavioral characteristics including externalizing, internalizing activity, attention, and impulsivity were also examined. Polytomous logistic regression analyses were used to evaluate direct effects of adverse environmental exposures with level of adolescent drinking. Structural equation modeling (SEM) was applied to simultaneously estimate the relation between early adversity variables, childhood characteristics, and drinking level at age 16 while controlling for significant covariates. Level of drinking among the adolescent offspring was directly predicted by prenatal exposure to alcohol, less parental strictness, and exposures to maltreatment and violence during childhood. Whites and offspring with older mothers were more likely to drink at higher levels. There was a significant indirect effect between childhood exposure to violence and adolescent drinking via childhood externalizing behavior problems. All other hypothesized indirect pathways were not significant. Thus most of the early adversity measures directly predicted adolescent drinking and did not operate via childhood behavioral dysregulation characteristics. These results highlight the importance of adverse environmental exposures on pathways to adolescent drinking. PMID:26994529

  7. Prenatal alcohol and other early childhood adverse exposures: Direct and indirect pathways to adolescent drinking.

    PubMed

    Cornelius, Marie D; De Genna, Natacha M; Goldschmidt, Lidush; Larkby, Cynthia; Day, Nancy L

    2016-01-01

    We examined direct and indirect pathways between adverse environmental exposures during gestation and childhood and drinking in mid-adolescence. Mothers and their offspring (n=917 mother/child dyads) were followed prospectively from second trimester to a 16-year follow-up assessment. Interim assessments occurred at delivery, 6, 10, and 14years. Adverse environmental factors included gestational exposures to alcohol, tobacco, and marijuana, exposures to childhood maltreatment and violence, maternal psychological symptoms, parenting practices, economic and home environments, and demographic characteristics of the mother and child. Indirect effects of early child behavioral characteristics including externalizing, internalizing activity, attention, and impulsivity were also examined. Polytomous logistic regression analyses were used to evaluate direct effects of adverse environmental exposures with level of adolescent drinking. Structural equation modeling (SEM) was applied to simultaneously estimate the relation between early adversity variables, childhood characteristics, and drinking level at age 16 while controlling for significant covariates. Level of drinking among the adolescent offspring was directly predicted by prenatal exposure to alcohol, less parental strictness, and exposures to maltreatment and violence during childhood. Whites and offspring with older mothers were more likely to drink at higher levels. There was a significant indirect effect between childhood exposure to violence and adolescent drinking via childhood externalizing behavior problems. All other hypothesized indirect pathways were not significant. Thus most of the early adversity measures directly predicted adolescent drinking and did not operate via childhood behavioral dysregulation characteristics. These results highlight the importance of adverse environmental exposures on pathways to adolescent drinking. PMID:26994529

  8. Epilogue: Understanding Children Who Have Been Affected by Maltreatment and Prenatal Alcohol Exposure--Future Directions

    ERIC Educational Resources Information Center

    Hyter, Yvette D.; Way, Ineke

    2007-01-01

    This epilogue summarizes the six articles presented in the clinical forum focused on understanding children who have been affected by maltreatment and prenatal alcohol exposure. It presents common themes that emerged among the articles and future research directions.

  9. Exposure of Soil Microbial Communities to Chromium and Arsenic Alters Their Diversity and Structure

    PubMed Central

    Rizvi, Fariha Z.; Rehman, Yasir; Faisal, Muhammad; Hasnain, Shahida; McInerney, Michael J.; Krumholz, Lee R.

    2012-01-01

    Extensive use of chromium (Cr) and arsenic (As) based preservatives from the leather tanning industry in Pakistan has had a deleterious effect on the soils surrounding production facilities. Bacteria have been shown to be an active component in the geochemical cycling of both Cr and As, but it is unknown how these compounds affect microbial community composition or the prevalence and form of metal resistance. Therefore, we sought to understand the effects that long-term exposure to As and Cr had on the diversity and structure of soil microbial communities. Soils from three spatially isolated tanning facilities in the Punjab province of Pakistan were analyzed. The structure, diversity and abundance of microbial 16S rRNA genes were highly influenced by the concentration and presence of hexavalent chromium (Cr (VI)) and arsenic. When compared to control soils, contaminated soils were dominated by Proteobacteria while Actinobacteria and Acidobacteria (which are generally abundant in pristine soils) were minor components of the bacterial community. Shifts in community composition were significant and revealed that Cr (VI)-containing soils were more similar to each other than to As contaminated soils lacking Cr (VI). Diversity of the arsenic resistance genes, arsB and ACR3 were also determined. Results showed that ACR3 becomes less diverse as arsenic concentrations increase with a single OTU dominating at the highest concentration. Chronic exposure to either Cr or As not only alters the composition of the soil bacterial community in general, but affects the arsenic resistant individuals in different ways. PMID:22768219

  10. Exposure of soil microbial communities to chromium and arsenic alters their diversity and structure.

    PubMed

    Sheik, Cody S; Mitchell, Tyler W; Rizvi, Fariha Z; Rehman, Yasir; Faisal, Muhammad; Hasnain, Shahida; McInerney, Michael J; Krumholz, Lee R

    2012-01-01

    Extensive use of chromium (Cr) and arsenic (As) based preservatives from the leather tanning industry in Pakistan has had a deleterious effect on the soils surrounding production facilities. Bacteria have been shown to be an active component in the geochemical cycling of both Cr and As, but it is unknown how these compounds affect microbial community composition or the prevalence and form of metal resistance. Therefore, we sought to understand the effects that long-term exposure to As and Cr had on the diversity and structure of soil microbial communities. Soils from three spatially isolated tanning facilities in the Punjab province of Pakistan were analyzed. The structure, diversity and abundance of microbial 16S rRNA genes were highly influenced by the concentration and presence of hexavalent chromium (Cr (VI)) and arsenic. When compared to control soils, contaminated soils were dominated by Proteobacteria while Actinobacteria and Acidobacteria (which are generally abundant in pristine soils) were minor components of the bacterial community. Shifts in community composition were significant and revealed that Cr (VI)-containing soils were more similar to each other than to As contaminated soils lacking Cr (VI). Diversity of the arsenic resistance genes, arsB and ACR3 were also determined. Results showed that ACR3 becomes less diverse as arsenic concentrations increase with a single OTU dominating at the highest concentration. Chronic exposure to either Cr or As not only alters the composition of the soil bacterial community in general, but affects the arsenic resistant individuals in different ways. PMID:22768219

  11. Space Weathering Effects in Lunar Soils: The Roles of Surface Exposure Time and Bulk Chemical Composition

    NASA Technical Reports Server (NTRS)

    Zhang, Shouliang; Keller, Lindsay P.

    2011-01-01

    Space weathering effects on lunar soil grains result from both radiation-damaged and deposited layers on grain surfaces. Typically, solar wind irradiation forms an amorphous layer on regolith silicate grains, and induces the formation of surficial metallic Fe in Fe-bearing minerals [1,2]. Impacts into the lunar regolith generate high temperature melts and vapor. The vapor component is largely deposited on the surfaces of lunar soil grains [3] as is a fraction of the melt [4, this work]. Both the vapor-deposits and the deposited melt typically contain nanophase Fe metal particles (npFe0) as abundant inclusions. The development of these rims and the abundance of the npFe0 in lunar regolith, and thus the optical properties, vary with the soil mineralogy and the length of time the soil grains have been exposed to space weathering effects [5]. In this study, we used the density of solar flare particle tracks in soil grains to estimate exposure times for individual grains and then perform nanometer-scale characterization of the rims using transmission electron microscopy (TEM). The work involved study of lunar soil samples with different mineralogy (mare vs. highland) and different exposure times (mature vs. immature).

  12. Nitrogen isotopes in lunar soils as a measure of cosmic-ray exposure and regolith history

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Clayton, R. N.

    1977-01-01

    Previous studies have shown that the bulk of the nitrogen in soils has been implanted by the solar wind, that the N-15/N-14 ratio of the implanted nitrogen has apparently increased with time, and that both soils and rocks contain a nitrogen component greatly enriched in N-15, relative to natural abundance ratios, due to cosmic-ray spallation. An investigation was, therefore, conducted to test the feasibility of using spallation-produced N-15 for determining cosmic-ray exposure ages. Samples from several depths in the Apollo 15 deep drill core were analyzed. The data obtained have also been evaluated with regard to possible models for the prior history of the material now in the Apollo 15 core. In addition, analyses have been performed of several other soil samples considered for various reasons to be of particular interest, such as orange soil 74220 and its companion 74240, Apollo 16 drill core sample 60002, and the apparently peculiar fillet soil 67461. Wherever possible, analyses were carried out by step-wise heating rather than by total pyrolysis. On the basis of the results of the investigation it is concluded that nitrogen isotope ratio determinations provide a usable method for determining cosmic-ray exposures for soils.

  13. Directly coupled vs conventional time domain reflectometry in soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Time domain reflectometry (TDR), a technique for estimation of soil water, measures the travel time of an electromagnetic pulse on electrodes embedded in the soil, but has limited application in commercial agriculture due to costs, labor, and sensing depth. Conventional TDR systems have employed ana...

  14. Inter-laboratory evaluation of the ISO standard 11063 "Soil quality - Method to directly extract DNA from soil samples".

    PubMed

    Petric, I; Philippot, L; Abbate, C; Bispo, A; Chesnot, T; Hallin, S; Laval, K; Lebeau, T; Lemanceau, P; Leyval, C; Lindström, K; Pandard, P; Romero, E; Sarr, A; Schloter, M; Simonet, P; Smalla, K; Wilke, B-M; Martin-Laurent, F

    2011-03-01

    Extracting DNA directly from micro-organisms living in soil is a crucial step for the molecular analysis of soil microbial communities. However, the use of a plethora of different soil DNA extraction protocols, each with its own bias, makes accurate data comparison difficult. To overcome this problem, a method for soil DNA extraction was proposed to the International Organization for Standardization (ISO) in 2006. This method was evaluated by 13 independent European laboratories actively participating in national and international ring tests. The reproducibility of the standardized method for molecular analyses was evaluated by comparing the amount of DNA extracted, as well as the abundance and genetic structure of the total bacterial community in the DNA extracted from 12 different soils by the 13 laboratories. High quality DNA was successfully extracted from all 12 soils, despite different physical and chemical characteristics and a range of origins from arable soils, through forests to industrial sites. Quantification of the 16S rRNA gene abundances by real time PCR and analysis of the total bacterial community structure by automated ribosomal intergenic spacer analysis (A-RISA) showed acceptable to good levels of reproducibility. Based on the results of both ring-tests, the method was unanimously approved by the ISO as an international standard method and the normative protocol will now be disseminated within the scientific community. Standardization of a soil DNA extraction method will improve data comparison, facilitating our understanding of soil microbial diversity and soil quality monitoring. PMID:21256879

  15. Posttraumatic stress disorder in disaster relief workers following direct and indirect trauma exposure to Ground Zero.

    PubMed

    Zimering, Rose; Gulliver, Suzy B; Knight, Jeffrey; Munroe, James; Keane, Terence M

    2006-08-01

    The present study compared rates of posttraumatic stress disorder (PTSD) in relief workers at the World Trade Center collapse from two sources: direct exposure to the disaster site and indirect exposure through survivor narratives. Standardized clinical interviews for PTSD were conducted with 109 relief workers 6-8 months after the September 11th terrorist attacks. Rates of acute PTSD from direct and indirect exposure to traumatic stressors were 6.4% and 4.6%, respectively. The findings suggest that indirect exposures can lead to PTSD even when Criterion A1 of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-Text Revision (DSM-IV-TR; American Psychiatric Association, 2000, p. 463), i.e., "experienced by a family member or other close associate" is not met. Further research is necessary to define precisely the parameters of indirect traumatic exposure that may be linked to the development of PTSD. PMID:16929511

  16. Role of Direct and Indirect Violence Exposure on Externalizing Behavior in Children.

    PubMed

    Fleckman, Julia M; Drury, Stacy S; Taylor, Catherine A; Theall, Katherine P

    2016-06-01

    The objective of this study was to examine the association between externalizing behaviors and indirect violence exposure, assessed both within the household and at the community level, as well as the interaction effect of indirect and direct violence exposure. A sample of parents of children ages 4-15 who have not been referred or enrolled in child welfare (n = 82) were recruited from the greater New Orleans community. Externalizing behavior was assessed with the Child Behavior Checklist (CBCL). The child's indirect exposure to violence included witnessing community violence, witnessing physical assault, and witnessing fighting or domestic violence at home. Direct exposure to violence included the child experiencing physical aggression from a caregiver. All assessments were based on caregiver reports. To decrease potential for confounding, children were matched for analysis based on age, Hurricane Katrina exposure, and their propensity to be exposed to high indirect violence. Cumulative indirect exposure to violence was significantly positively correlated with CBCL scores. After controlling for key covariates, CBCL externalizing T score increased significantly by approximately 1.25 points for each level increase in indirect violence exposure (β = 1.25, SE = 0.57, p = 0.027). There also was a significant interaction between indirect and direct exposure to violence in the association with CBCL score (β = -0.08, SE = 0.03, p = 0.002). These findings extend previous research by demonstrating that exposure to both direct and cross-contextual indirect violence influences externalizing behaviors in children. Additionally, the findings suggest that community and household social environments are both important targets for interventions designed to decrease externalizing behaviors and improve long-term outcomes for youth at risk of exposure to violence. PMID:27184572

  17. The revised electromagnetic fields directive and worker exposure in environments with high magnetic flux densities.

    PubMed

    Stam, Rianne

    2014-06-01

    Some of the strongest electromagnetic fields (EMF) are found in the workplace. A European Directive sets limits to workers' exposure to EMF. This review summarizes its origin and contents and compares magnetic field exposure levels in high-risk workplaces with the limits set in the revised Directive. Pubmed, Scopus, grey literature databases, and websites of organizations involved in occupational exposure measurements were searched. The focus was on EMF with frequencies up to 10 MHz, which can cause stimulation of the nervous system. Selected studies had to provide individual maximum exposure levels at the workplace, either in terms of the external magnetic field strength or flux density or as induced electric field strength or current density. Indicative action levels and the corresponding exposure limit values for magnetic fields in the revised European Directive will be higher than those in the previous version. Nevertheless, magnetic flux densities in excess of the action levels for peripheral nerve stimulation are reported for workers involved in welding, induction heating, transcranial magnetic stimulation, and magnetic resonance imaging (MRI). The corresponding health effects exposure limit values for the electric fields in the worker's body can be exceeded for welding and MRI, but calculations for induction heating and transcranial magnetic stimulation are lacking. Since the revised European Directive conditionally exempts MRI-related activities from the exposure limits, measures to reduce exposure may be necessary for welding, induction heating, and transcranial nerve stimulation. Since such measures can be complicated, there is a clear need for exposure databases for different workplace scenarios with significant EMF exposure and guidance on good practices. PMID:24557933

  18. The Revised Electromagnetic Fields Directive and Worker Exposure in Environments With High Magnetic Flux Densities

    PubMed Central

    Stam, Rianne

    2014-01-01

    Some of the strongest electromagnetic fields (EMF) are found in the workplace. A European Directive sets limits to workers’ exposure to EMF. This review summarizes its origin and contents and compares magnetic field exposure levels in high-risk workplaces with the limits set in the revised Directive. Pubmed, Scopus, grey literature databases, and websites of organizations involved in occupational exposure measurements were searched. The focus was on EMF with frequencies up to 10 MHz, which can cause stimulation of the nervous system. Selected studies had to provide individual maximum exposure levels at the workplace, either in terms of the external magnetic field strength or flux density or as induced electric field strength or current density. Indicative action levels and the corresponding exposure limit values for magnetic fields in the revised European Directive will be higher than those in the previous version. Nevertheless, magnetic flux densities in excess of the action levels for peripheral nerve stimulation are reported for workers involved in welding, induction heating, transcranial magnetic stimulation, and magnetic resonance imaging (MRI). The corresponding health effects exposure limit values for the electric fields in the worker’s body can be exceeded for welding and MRI, but calculations for induction heating and transcranial magnetic stimulation are lacking. Since the revised European Directive conditionally exempts MRI-related activities from the exposure limits, measures to reduce exposure may be necessary for welding, induction heating, and transcranial nerve stimulation. Since such measures can be complicated, there is a clear need for exposure databases for different workplace scenarios with significant EMF exposure and guidance on good practices. PMID:24557933

  19. Validation of Sensor-Directed Spatial Simulated Annealing Soil Sampling Strategy.

    PubMed

    Scudiero, Elia; Lesch, Scott M; Corwin, Dennis L

    2016-07-01

    Soil spatial variability has a profound influence on most agronomic and environmental processes at field and landscape scales, including site-specific management, vadose zone hydrology and transport, and soil quality. Mobile sensors are a practical means of mapping spatial variability because their measurements serve as a proxy for many soil properties, provided a sensor-soil calibration is conducted. A viable means of calibrating sensor measurements over soil properties is through linear regression modeling of sensor and target property data. In the present study, two sensor-directed, model-based, sampling scheme delineation methods were compared to validate recent applications of soil apparent electrical conductivity (EC)-directed spatial simulated annealing against the more established EC-directed response surface sampling design (RSSD) approach. A 6.8-ha study area near San Jacinto, CA, was surveyed for EC, and 30 soil sampling locations per sampling strategy were selected. Spatial simulated annealing and RSSD were compared for sensor calibration to a target soil property (i.e., salinity) and for evenness of spatial coverage of the study area, which is beneficial for mapping nontarget soil properties (i.e., those not correlated with EC). The results indicate that the linear modeling EC-salinity calibrations obtained from the two sampling schemes provided salinity maps characterized by similar errors. The maps of nontarget soil properties show similar errors across sampling strategies. The Spatial Simulated Annealing methodology is, therefore, validated, and its use in agronomic and environmental soil science applications is justified. PMID:27380070

  20. Ecological risk assessment of radiological exposure to depleted uranium in soils at a weapons testing facility.

    SciTech Connect

    Hlohowskyj, I.; Cheng, J.; Tsao, C.; Environmental Assessment

    2004-01-01

    The potential for unacceptable risks to biota from radiological exposure to depleted uranium (DU) in soils was evaluated at two sites where DU weapons testing had been conducted in the past. A screening risk assessment was conducted to determine if measured concentrations of DU-associated radionuclides in site soils exceed radionuclide levels considered protective of biota. While concentrations of individual radionuclides did not exceed acceptable levels, total radionuclide concentrations could result in potentially unacceptable doses to exposed biota. Thus, a receptor-specific assessment was conducted to estimate external and internal radiological doses to vegetation and wildlife known or expected to occur at the sites. Wildlife evaluated included herbivores, omnivores, and top-level predators. Internal dose estimates to wildlife considered exposure via fugitive dust inhalation and soil and food ingestion; root uptake was the primary exposure route evaluated for vegetation. Total doses were compared with acceptable dose levels of 1.0 and 0.1 rad/day for vegetation and wildlife, respectively, with potentially unacceptable risks indicated for doses exceeding these levels. All estimated doses were below or approximated acceptable levels, typically by an order of magnitude or more. These results indicate that current levels of DU in soils do not pose unacceptable radiological risks to biota at the sites evaluated.

  1. Assessment of occupational exposure to polycyclic aromatic hydrocarbons via involuntary ingestion of soil from contaminated soils in Lagos, Nigeria.

    PubMed

    Adetunde, Oluwatoyin T; Mills, Graham A; Olayinka, Kehinde O; Alo, Babajide I

    2014-01-01

    Soils from 12 sites in Lagos area, Nigeria impacted by anthropogenic activities were extracted by ultrasonication and analysed for the concentration of 16 priority polycyclic aromatic hydrocarbons (PAHs) by gas chromatograph-mass spectrometer (GC-MS). The concentration of the sum of PAHs ranged from 0.2 to 254 μg/g at these sites. The sum benzo[a]pyrene-equivalent dose (BaPeq) at the sites ranged from 0.0 (K, forest soil) to 16.7 μg/g (C, the lubricating oil depot soil). Mean daily intake (MDI) for the composite soils samples when compared that of food revealed that some of the individual PAH in samples from sites A (Dump site), C (Depot and loading point for used for black oil), F (Dump site), G(petroleum depot), H (Roadside) and L (Car park) exceeded the recommended the recommended MDI threshold for food, indicating some risk associated with activities on these sites based on this ingestion estimate exceeded value. 8.2 × 10(-6), 7.1 × 10(-7), 1.2 × 10(-4), 4.9 × 10(-7), 7.3 × 10(-7), 1.4 × 10(-5), 7.9 × 10(-5), 4.6 × 10(-6), 3.4 × 10(-7), 2.4 × 10(-7), 2.2 × 10(-7) and 1.1 × 10(-4) estimated theoretical cancer risk (ER) for an adult with a body weight of 70 kg working on sites were composite soil samples A, B, C, D, E, F, G, H, I, J, K and L respectively were sampled. The ER from occupational exposure to surface soil based on oral ingestion were all higher than the target risk of 1 × 10(-6) for normal exposure but were all within the 1 × 10(-4) for extreme exposure for most of the sites except for site C and L. The differences in concentration and risk were related to the different activities (e.g., handling of petroleum products, open burning, bush burning) undertaken at these locations. However, it should be noted here that the resultant risk could be overestimated, since these calculations were based on an exhaustive extraction technique which may be different from uptake by the human guts (bioavailability study). PMID:25320853

  2. Spatially resolved hazard and exposure assessments: an example of lead in soil at Lavrion, Greece.

    PubMed

    Tristán, E; Demetriades, A; Ramsey, M H; Rosenbaum, M S; Stavrakis, P; Thornton, I; Vassiliades, E; Vergou, K

    2000-01-01

    Spatially resolved hazard assessment (SRHA) and spatially resolved exposure assessment (SREA) are methodologies that have been devised for assessing child exposure to soil containing environmental pollutants. These are based on either a quantitative or a semiquantitative approach. The feasibility of the methodologies has been demonstrated in a study assessing child exposure to Pb accessible in soil at the town of Lavrion in Greece. Using a quantitative approach, both measured and kriged concentrations of Pb in soil are compared with an "established" statutory threshold value. The probabilistic approach gives a refined classification of the contaminated land, since it takes into consideration the uncertainty in both the actual measurement and estimated kriged values. Two exposure assessment models (i.e., IEUBK and HESP) are used as the basis of the quantitative SREA methodologies. The significant correlation between the blood-Pb predictions, using the IEUBK model, and measured concentrations provides a partial validation of the method, because it allows for the uncertainty in the measurements and the lack of some site-specific measurements. The semiquantitative applications of SRHA and SREA incorporate both qualitative information (e.g., land use and dustiness of waste) and quantitative information (e.g., distance from wastes and distance from industry). The significant correlation between the results of these assessments and the measured blood-Pb levels confirms the robust nature of this approach. Successful application of these methodologies could reduce the cost of the assessment and allow areas to be prioritized for further investigation, remediation, or risk management. PMID:10677144

  3. Spatially resolved hazard and exposure assessments: An example of lead in soil at Lavrion, Greece

    SciTech Connect

    Tristan, E.; Demetriades, A.; Ramsey, M.H.; Rosenbaum, M.S.; Stavrakis, P.; Thornton, I.; Vassiliades, E.; Vergou, K.

    2000-01-01

    Spatially resolved hazard assessment (SRHA) and spatially resolved exposure assessment (SREA) are methodologies that have been devised for assessing child exposure to soil containing environmental pollutants. These are based on either a quantitative or a semiquantitative approach. The feasibility of the methodologies has been demonstrated in a study assessing child exposure to Pb accessible in soil at the town of Lavrion in Greece. Using a quantitative approach, both measured and kriged concentrations of Pb in soil are compared with an established statutory threshold value. The probabilistic approach gives a refined classification of the contaminated land, since it takes into consideration the uncertainty in both the actual measurement and estimated kriged values. Two exposure assessment models (i.e., IEUBK and HESP) are used as the basis of the quantitative SREA methodologies. The significant correlation between the blood-Pb predictions, using the IEUBK model, and measured concentrations provides a partial validation of the method, because it allows for the uncertainty in the measurements and the lack of some site-specific measurements. The semiquantitative applications of SRHA and SREA incorporate both qualitative information (e.g., land use and dustiness of waste) and quantitative information (e.g., distance from wastes and distance from industry). The significant correlation between the results of these assessments and the measured blood-Pb levels confirms the robust nature of this approach. Successful application of these methodologies could reduce the cost of the assessment and allow areas to be prioritized for further investigation, remediation, or risk management.

  4. Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China.

    PubMed

    Chen, Kai; Liao, Qi Lin; Ma, Zong Wei; Jin, Yang; Hua, Ming; Bi, Jun; Huang, Lei

    2015-04-01

    Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population. PMID:25410308

  5. Ecotoxicological effects on the earthworm Eisenia fetida following exposure to soil contaminated with imidacloprid.

    PubMed

    Zhang, Qingming; Zhang, Baohua; Wang, Caixia

    2014-11-01

    Imidacloprid, a neonicotinoid insecticide, has been used widely in agriculture worldwide. The adverse effects of imidacloprid on exposed biota have brought it increasing attention. However, knowledge about the effects of imidacloprid on antioxidant defense systems and digestive systems in the earthworm is vague and not comprehensive. In the present study, the changes in the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), cellulase, reactive oxygen species (ROS), and malondialdehyde (MDA) in the earthworm Eisenia fetida exposed to artificial soil treated with imidacloprid were examined systematically. The results showed that the activity of these biomarkers was closely related to the dose and duration of the exposure to imidacloprid. The activity of SOD was stimulated significantly at doses of 0.66 and 2 mg kg(-1) imidacloprid but markedly inhibited at a dose of 4 mg kg(-1) imidacloprid with prolonged exposure. The activities of CAT and POD increased irregularly at 0.2-4 mg kg(-1) imidacloprid over different exposure times. The level of ROS at a dose of 2 or 4 mg kg(-1) imidacloprid was significantly increased over the entire exposure period. When the concentration of imidacloprid was above 0.66 mg kg(-1), the balance of the activity of the antioxidant enzymes and ROS level was interrupted. The activity of cellulase decreased significantly with prolonged exposure. At the stress of 4 mg kg(-1) imidacloprid, the content of MDA was significantly increased with increasing exposure time. The results of the present study suggest that imidacloprid has a potentially harmful effect on E. fetida and may be helpful for assessment of the risk of imidacloprid to the soil ecosystem environment. However, to obtain more comprehensive toxicity data, it is necessary to investigate the effects of imidacloprid on earthworm using native soils in the future work. PMID:24938817

  6. Assessment of the human health risks posed by exposure to chromium-contaminated soils

    SciTech Connect

    Sheehan, P.J.; Meyer, D.M.; Sauer, M.M.; Paustenbach, D.J. )

    1991-02-01

    Millions of tons of chromite-ore processing residue have been used as fill in various locations in northern New Jersey and elsewhere in the United States. The primary toxicants in the residue are trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)). The hazard posed by Cr(III) is negligible due to its low acute and chronic toxicity. In contrast, Cr(VI) is a human carcinogen following inhalation of high concentrations. It can also cause allergic contact dermatitis. This evaluation addresses a residential site where the arithmetic mean (x) and geometric mean (gm) concentrations of Cr(III) in soil were 2879 and 1212 mg/kg (ppm). The mean concentrations of Cr(VI) were 180 and 4 mg/kg, respectively. The uptake (absorbed dose) of Cr(III) via soil ingestion, consumption of homegrown vegetables, and ingestion of inspired particles was determined. The uptake of Cr(VI) via dermal absorption from contact with surface soil and building wall surfaces, as well as inhalation, was also evaluated. The techniques used in this assessment are applicable for evaluating the human health risks posed by any residential site having contaminated soil. The potential for both sensitized and unsensitized persons to develop allergic contact dermatitis due to exposure to soil contaminated at these levels was found to be negligible. The estimated average daily dose (ADD) via ingestion and dermal absorption for the maximally exposed individual (MEI) was about 1500- and 40-fold below the EPA reference dose (RfD) for Cr(III) and Cr(VI), respectively. It was shown that for residential sites, the most important route of exposure to Cr(III) was incidental soil ingestion. Although not relevant to these sites specifically, if garden vegetables could be successfully grown in these soils, then they would probably be the predominant source of uptake of Cr(III). 163 refs.

  7. Minimal second language exposure, SES, and early word comprehension: New evidence from a direct assessment*

    PubMed Central

    Deanda, Stephanie; Arias-Trejo, Natalia; Poulin-Dubois, Diane; Zesiger, Pascal; Friend, Margaret

    2015-01-01

    Although the extant literature provides robust evidence of the influence of language exposure and socioeconomic status (SES) on language acquisition, it is unknown how sensitive the early receptive vocabulary system is to these factors. The current study investigates effects of minimal second language exposure and SES on the comprehension vocabulary of 16-month-old children in the language in which they receive the greatest exposure. Study 1 revealed minimal second language exposure and SES exert significant and independent effects on a direct measure of vocabulary comprehension in English-dominant and English monolingual children (N = 72). In Study 2, we replicated the effect of minimal second language exposure in Spanish-dominant and Spanish monolingual children (N = 86), however no effect of SES on vocabulary was obtained. Our results emphasize the sensitivity of the language system to minimal changes in the environment in early development. PMID:26957947

  8. Toxicological responses of red-backed salamanders (Plethodon cinereus) to soil exposures of copper.

    PubMed

    Bazar, Matthew A; Quinn, Michael J; Mozzachio, Kristie; Bleiler, John A; Archer, Christine R; Phillips, Carlton T; Johnson, Mark S

    2009-07-01

    Copper (Cu) has widespread military use in munitions and small arms, particularly as a protective jacket for lead projectiles. The distribution of Cu at many US military sites is substantial and sites of contamination include habitats in and around military storage facilities, manufacturing, load and packing plants, open burning/open detonation areas, and firing ranges. Some of these areas include habitat for amphibian species, which generally lack toxicity data for risk assessment purposes. In an effort to ascertain Cu concentrations in soil that are toxic to terrestrial amphibians, 100 red-backed salamanders (Plethodon cinereus) were randomly sorted by weight, assigned to either a control soil or one of four treatments amended with copper acetate in soil, and exposed for 28 days. Analytical mean soil concentrations were 18, 283, 803, 1333, and 2700 mg Cu/kg soil dry weight. Food consisted of uncontaminated flightless Drosophila melanogaster. Survival was reduced in salamanders exposed to 1333 and 2700 mg/kg by 55% and 100%, respectively. Mortality/morbidity occurred within the first 4 days of exposure. These data suggest that a Cu soil concentration of and exceeding 1333.3 +/- 120.2 mg/kg results in reduced survival, whereas hematology analyses suggest that a concentration of and exceeding 803.3 +/- 98.4 mg/kg might result in reduced total white blood cell count. No effects were observed at 283.3 +/- 36.7 mg/kg. PMID:18825446

  9. Impact of Soil Cadmium on Land Snails: A Two-Stage Exposure Approach under Semi-Field Conditions Using Bioaccumulative and Conchological End-Points of Exposure

    PubMed Central

    Nica, Dragos V.; Filimon, Marioara Nicoleta; Bordean, Despina-Maria; Harmanescu, Monica; Draghici, George Andrei; Dragan, Simona; Gergen, Iosif I.

    2015-01-01

    Land snails are highly tolerant to cadmium exposure and are able to accumulate soil cadmium independently of food ingestion. However, little information exists on the kinetics of cadmium retention in terrestrial gastropods exposed to an increase in the soil cadmium content, over time. There is also little knowledge about how exposure to cadmium-polluted soils influences shell growth and architecture. In this context, we examined cadmium accumulation in the hepatopancreas and shell of juvenile Cantareus aspersus exposed to elevating high levels of cadmium in soil. Also, the toxicity of cadmium to snails was assessed using a range of conchological endpoints, including shell height, width, volume, allometry and integrity. Test snails, aged three months, were reared under semi-field conditions, fed an uncontaminated diet and exposed first, for a period of 30 days, to a series of soil cadmium concentrations, and then, for a second period of 30 days, to soils with higher cadmium content. Cadmium showed a dose-dependent accumulation in both the hepatopancreas and shell. The kinetics of cadmium retention in the hepatopancreas of snails previously exposed to cadmium-spiked soils was significantly influenced by a new exposure event. The shell was not a relevant bioaccumulator for soil cadmium. Under the present experimental conditions, only high cadmium exposure significantly affected either the shell growth or snail survival. There was no consistent effect on shell allometry, but the shell integrity, especially in rapidly growing parts, appeared to be affected by high cadmium exposure. Our results attest to the value of hepatopancreas for describing cadmium retention in land snails and to the difficulty of using conchological parameters in field surveys for estimating the environmental hazard of soil cadmium. PMID:25790135

  10. Quantitative Field Testing Rotylenchulus reniformis DNA from Metagenomic Samples Isolated Directly from Soil

    PubMed Central

    Showmaker, Kurt; Lawrence, Gary W.; Lu, Shien; Balbalian, Clarissa; Klink, Vincent P.

    2011-01-01

    A quantitative PCR procedure targeting the β-tubulin gene determined the number of Rotylenchulus reniformis Linford & Oliveira 1940 in metagenomic DNA samples isolated from soil. Of note, this outcome was in the presence of other soil-dwelling plant parasitic nematodes including its sister genus Helicotylenchus Steiner, 1945. The methodology provides a framework for molecular diagnostics of nematodes from metagenomic DNA isolated directly from soil. PMID:22194958

  11. Risk Factors for and Behavioral Consequences of Direct Versus Indirect Exposure to Violence.

    PubMed

    Zimmerman, Gregory M; Posick, Chad

    2016-01-01

    Research suggests that direct exposure (personal victimization) and indirect exposure (witnessing or hearing about the victimization of a family member, friend, or neighbor) to violence are correlated. However, questions remain about the co-occurrence of these phenomena within individuals. We used data on 1915 youths (with an average age of 12 years at baseline) from the Project on Human Development in Chicago Neighborhoods to examine this issue. Results indicated that youths who tended to be personally victimized were also likely to witness violence; conversely, youths who disproportionately witnessed violence were relatively unlikely to experience personal victimization. In addition, direct and indirect exposures to violence were associated with subsequent adverse outcomes in similar ways. The key distinguishing factor was, rather, the cumulative level of violence (both direct and indirect) to which youths were exposed. PMID:26562101

  12. Direct and surrogate measures of soil water content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An expert group from five nations and three continents did comparative trials of soil water sensing methods under laboratory and field conditions at the behest of the joint division of the International Atomic Energy Agency and the United Nations Food and Agricultural Organization (FAO), resulting i...

  13. Enhanced Sensitivity of Direct Beryllium Determination in Soil by Laser-Induced Breakdown Spectrometry

    NASA Astrophysics Data System (ADS)

    Popov, A. M.; Kozhnov, M. O.; Zaytsev, S. M.; Zorov, N. B.; Labutin, T. A.

    2015-11-01

    Beryllium is an extremely hazardous substance because of its effects on the human body. Regulatory standards establishing the maximum permissible concentration of Be in soils of farmlands and population centers at 1.08 mg/kg are currently in the approval process. Be in soils could be determined below this level by laser-induced breakdown spectroscopy (LIBS) using UV laser radiation (355 nm). A recording delay of 0.75 μs and an exposure of 1 μs were optimal for the LIBS Be analysis. The Be detection limit in soils under these conditions was 0.07 mg/kg.

  14. The International year of soils: thoughts on future directions for experiments in soil erosion research

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2015-04-01

    The 2015 UN Year of Soils (IYS), implemented by the FAO, aims to increase awareness and understanding of the importance of soil for food security and essential ecosystem functions. The IYS has six specific objectives, ranging from raising the awareness among civil society and decision makers about the profound importance of soils, to the development of policies supporting the sustainable use of the non-renewable soil resource. For scientists and academic teachers using experiments to study soil erosion processes, two objectives appear of particular relevance. First is need for the rapid capacity enhancement for soil information collection and monitoring at all levels (global, regional and national). While at first glance, this objective appears to relate mostly to traditional mapping, sampling and monitoring, the threat of large-scale soil loss, at least with regards to their ecosystem services, illustrates the need for approaches of studying soils that avoids such irreversible destruction. Relying on often limited data and their extrapolation does not cover this need for soil information because rapid change of the drivers of change itself carry the risk of unprecedented soil reactions not covered by existing data sets. Experiments, on the other hand, offer the possibility to simulate and analyze future soil change in great detail. Furthermore, carefully designed experiments may also limit the actual effort involved in collecting the specific required information, e.g. by applying tests designed to study soil system behavior under controlled conditions, compared to field monitoring. For rainfall simulation, experiments should therefore involve the detailed study of erosion processes and include detailed recording and reporting of soil and rainfall properties. The development of a set of standardised rainfall simulations would widen the use data collected by such experiments. A second major area for rainfall simulation lies in the the education of the public about

  15. Direct measurement of surface carbon concentrations for lunar soil breccias

    NASA Technical Reports Server (NTRS)

    Filleux, C.; Spear, R. H.; Tombrello, T. A.; Burnett, D. S.

    1978-01-01

    A nuclear reaction depth profiling technique previously described by Filleux et al. (1977) has been used to measure the depth distribution of C on grain surfaces for Apollo 11, 15, 16 and 17 soil breccias. The surface C concentration of all samples studied lies between 2 and 8 times 10 to the 15th atoms per sq cm, showing no correlation with the volume C, which varies over an order of magnitude. If the observed variation represents the presence of unexposed grains on the surfaces studied, these results indicate a steady state surface C concentration of 5 to 10 times 10 to the 15th atoms per sq cm, accumulated over a time scale short compared with that required for the formation of volume-related C and with the mean lifetime of grains at the lunar surface. About one-third to one-half of the total C in lunar soil seems to be surface-correlated.

  16. Radiation exposure and dose to small mammals in radon-rich soils.

    PubMed

    Macdonald, C R; Laverock, M J

    1998-07-01

    Protection of the environment from radionuclide releases requires knowledge of the normal background levels of radiation exposure in the exposed biotic community and an estimate of the detriment caused by additional exposure. This study modeled the background exposure and dose to the lungs of small burrowing mammals from 222Rn in artificial burrows in radon-rich soils at a site in southeastern Manitoba. E-PERM chambers used to measure 222Rn in soil showed good reproducibility of measurement, with an average coefficient of variance (CV) of about 10%. Geometric mean (GM) 222Rn concentrations at nine randomly selected sites ranged from 5,490 Bq/m3 (GSD = 1.57, n = 7) to 41,000 Bq/m3 (GSD = 1.02, n = 5). Long-term monitoring of 222Rn concentrations in artificial burrows showed large variation within and between burrows and did not show consistent variation with season, orientation of the burrow opening, or levels of 226Ra in the soil. Annual GM concentrations in individual burrows ranged from 7,480 Bq/m3 (GSD = 1.60) to 18,930 Bq/m3 (GSD = 1.81) in burrows several meters apart. A grand GM of 9,990 Bq/m3 (GSD = 1.81, n = 214) was measured over the site for the year. An exposure model was constructed for five small mammal species based on their respiration rates and the number of hours spent in the burrow, active or hibernating, exposed to soil gas 222Rn, and the time spent out of the burrow exposed to atmospheric 222Rn. A background dose of 0.9 mGy/a from atmospheric 222Rn (40 Bq/m3) was estimated for a large-bodied (80 kg), nonburrowing animal living on the soil surface. The highest exposures (mJ/a) in burrowing mammals occurred in those species with the highest respiration rates. Hibernation accounted for a small fraction of total annual exposure (<5%) because of very low respiration rates during this period. Absorbed dose to lung (mGy/a) was highest in the pocket gopher and decreased in the larger animals because of larger lung mass. Using mean 222Rn concentrations

  17. Lead exposure from soil in Peruvian mining towns: a national assessment supported by two contrasting examples

    PubMed Central

    Bravo, Carolina; Gil, Vladimir; Sherpa, Shaky; Jack, Darby

    2012-01-01

    Abstract Objective To estimate the population of Peru living in the vicinity of active or former mining operations that could be exposed to lead from contaminated soil. Methods Geographic coordinates were compiled for 113 active mines, 138 ore processing plants and 3 smelters, as well as 7743 former mining sites. The population living within 5 km of these sites was calculated from census data for 2000. In addition, the lead content of soil in the historic mining town of Cerro de Pasco and around a recent mine and ore processing plant near the city of Huaral was mapped in 2009 using a hand-held X-ray fluorescence analyser. Findings Spatial analysis indicated that 1.6 million people in Peru could be living within 5 km of an active or former mining operation. Two thirds of the population potentially exposed was accounted for by 29 clusters of mining operations, each with a population of over 10 000 each. These clusters included 112 active and 3438 former mining operations. Soil lead levels exceeded 1200 mg/kg, a reference standard for residential soil, in 35 of 74 sites tested in Cerro de Pasco but in only 4 of 47 sites tested around the newer operations near Huaral. Conclusion Soil contamination with lead is likely to be extensive in Peruvian mining towns but the level of contamination is spatially far from uniform. Childhood exposure by soil ingestion could be substantially reduced by mapping soil lead levels, making this information public and encouraging local communities to isolate contaminated areas from children. PMID:23284193

  18. Correlation functions for describing and reconstructing soil microstructure: the use of directional correlation functions

    NASA Astrophysics Data System (ADS)

    Karsanina, Marina; Gerke, Kirill; Skvortsova, Elena; Mallants, Dirk

    2015-04-01

    -scale modelling of soil properties, soil degradation monitoring, and description of spatial dynamics of soil microbial activity. This work was partially supported by RSF grant 14-17-00658 (directional correlation functions) and RFBR grants 13-04-00409-a and 13-05-01176-a.

  19. The identification of carbamazepine biodegrading phylotypes and phylotypes sensitive to carbamazepine exposure in two soil microbial communities.

    PubMed

    Thelusmond, Jean-Rene; Strathmann, Timothy J; Cupples, Alison M

    2016-11-15

    Carbamazepine (CBZ), an antiepileptic drug, has been introduced into agricultural soils via irrigation with treated wastewater and biosolids application. Such contamination is problematic because CBZ is persistent and the risks to ecosystems or human health are unknown. The current study examined CBZ biodegradation in two agricultural soils (soil 1 and 2) and the effects on the soil microbial communities during CBZ exposure. The experimental design involved three CBZ concentrations (50, 500, 5000ng/g), under aerobic as well as anaerobic conditions. CBZ concentrations were determined using solid phase extraction and LC MS/MS. The effect of CBZ on the soil microbial community was investigated using high throughput sequencing and a computational approach to predict functional composition of the metagenomes (phylogenetic investigation of communities by reconstruction of unobserved states, PICRUSt). The most significant CBZ biodegradation occurred in soil 1 under aerobic conditions. In contrast, CBZ biodegradation was limited under anaerobic conditions in soil 1 and under both conditions in soil 2. For soil 1, several phylotypes were enriched following CBZ degradation compared to the controls, including unclassified Sphingomonadaceae, Xanthomonadaceae and Rhodobacteraceae, as well as Sphingomonas, Aquicella and Microvirga. These phylotypes are considered putative CBZ degraders as they appear to be benefiting from CBZ biodegradation. PICRUSt revealed that soil 1 contained a greater abundance of xenobiotic degrading genes compared to soil 2, and thus, this analysis method offers a potential valuable approach for predicting CBZ attenuation in soils. PICRUSt analysis also implicated Sphingomonadaceae and Xanthomonadaceae in drug metabolism. Interestingly, numerous phylotypes decreased in abundance following CBZ exposure and these varied with soil type, concentration, duration of exposure, and the availability of oxygen. For three phylotypes (Flavobacterium, 3 genus incertae

  20. Emotional Distress and Posttraumatic Stress in Children: The Impact of Direct versus Indirect Exposure

    ERIC Educational Resources Information Center

    Bhushan, Braj; Kumar, J. Sathya

    2009-01-01

    This study examined whether familiarity with the physical environment and verbal/pictorial exposure to a tsunami also inducted posttraumatic stress symptoms in adolescents. The Impact of Event Scale (IES) and Pediatric Emotional Distress Scale (PEDS) were administered to 231 subjects (130 directly exposed and 101 indirectly exposed). The directly…

  1. The effects of exposure and climate on the weathering of late Pleistocene and Holocene Alpine soils

    NASA Astrophysics Data System (ADS)

    Egli, Markus; Sartori, Giacomo; Mirabella, Aldo; Giaccai, Daniele

    2010-01-01

    The main aim of this study was to examine the influence of exposure and consequently climate, on the chemical weathering of soils which had developed after the ice retreat of the last glaciation in Northern Italy. This was done by comparing soils developing at north- and south-facing sites on siliceous parent material. There is very little data available on weathering rates and organic matter (OM) as a function of climate and exposure in such environments. Weathering rates (elemental leaching) over the whole lifetime of the soils are higher on north-facing sites. Total organic C and N contents, organic matter stocks and organic matter fractions were analysed to decipher the causes of this difference in weathering behaviour. For the organic matter fractions, we compared the easily oxidisable and stable (resistant to H 2O 2 treatment) organic matter fractions, water-soluble phenolic materials and alkaline-extractable fractions of the various sites. The abundance of soil organic carbon (SOC) tends to have a non-linear climate dependency. The highest amounts of SOC were measured near the timberline. In addition, compared to south-facing sites, soils on north-facing slopes have a higher organic matter content and a significantly lower degree of humification. Undecomposed or weakly degraded organic matter accumulated on north-facing sites due to less favourable thermal conditions and a higher acidity. With northern exposure, fulvic acids were more easily transported within the soil profile than humic acids and predominately gave rise to the migration (eluviation) of Fe and Al compounds due to their -COOH and -OH functional groups. Furthermore, water-soluble phenolic materials, which are more abundant on north-facing sites, have accelerated the leaching of Al. Accumulation of weakly degraded OM and the subsequently higher production of organic ligands have enhanced the eluviation of Fe and Al. Patterns of weathering processes in Alpine environments are strongly linked to

  2. Assessment of plant uptake models used in exposure assessment tools for soils contaminated with organic pollutants.

    PubMed

    Takaki, Koki; Wade, Andrew J; Collins, Chris D

    2014-10-21

    The aim of this study was to evaluate and improve the accuracy of plant uptake models for neutral hydrophobic organic pollutants (1 < logK(OW) < 9, -8 < logK(AW) < 0) used in regulatory exposure assessment tools, using uncertainty and sensitivity analyses. The models considered were RAIDAR, EUSES, CSOIL, CLEA, and CalTOX. In this research, CSOIL demonstrated the best performance of all five exposure assessment tools for root uptake from polluted soil in comparison with observed data, but no model predicted shoot uptake well. Recalibration of the transpiration and volatilisation parameters improved the performance of CSOIL and CLEA. The dominant pathway for shoot uptake simulated differed according to the properties of the chemical under consideration; those with a higher air-water partition coefficient were transported into shoots via the soil-air-plant pathway, while chemicals with a lower octanol-water partition coefficient and air-water partition coefficient were transported via the root. The soil organic carbon content was a particularly sensitive parameter in each model and using a site specific value improved model performance. PMID:25203369

  3. Direct measurement of surface carbon concentrations. [in lunar soil

    NASA Technical Reports Server (NTRS)

    Filleux, C.; Tombrello, T. A.; Burnett, D. S.

    1977-01-01

    Measurements of surface concentrations of carbon in lunar soils and soil breccias provide information on the origin of carbon in the regolith. The reaction C-12 (d, p sub zero) is used to measure 'surface' and 'volume' concentrations in lunar samples. This method has a depth resolution of 1 micron, which permits only a 'surface' and a 'volume' component to be measured. Three of four Apollo 16 double drive tube samples show a surface carbon concentration of about 8 by 10 to the 14th power/sq cm, whereas the fourth sample gave 4 by 10 to the 14th power/sq cm. It can be convincingly shown that the measured concentration does not originate from fluorocarbon or hydrocarbon contaminants. Surface adsorbed layers of CO or CO2 are removed by a sputter cleaning procedure using a 2-MeV F beam. It is shown that the residual C concentration of 8 by 10 to the 14th power/sq cm cannot be further reduced by increased F fluence, and it is therefore concluded that it is truly lunar. If one assumes that the measured surface C concentration is a steady-state concentration determined only by a balance between solar-wind implantation and sputtering, a sputter erosion rate of 0.1 A/yr is obtained. However, it would be more profitable to use an independently derived sputter erosion rate to test the hypothesis of a solar-wind origin of the surface carbon.

  4. The dating of pre-exposure times of lunar rocks and soils

    NASA Technical Reports Server (NTRS)

    Eugster, O.

    1986-01-01

    Xenon produced by fission of uranium, thorium and plutonium has repeatedly been observed in lunar rocks and soils. In two basaltic rocks and in two soils Xe was found originating from fission of U-235 induced by neutrons which are due to the interactions of cosmic ray particles with lunar matter. Two facts lead to this conclusion: (1) fission Xe is present in excess of that expected for the U, Th, and Pu concentrations and for the gas retention age of the samples; and (2) the Xe-134/Xe-136 ratio of excess fission Xe is close to 1.25 as expected for neutron induced fission of U-235. Information on the duration of the exposure to cosmic rays was obtained from the Kr-81-Kr systematics whereas the effective shielding conditions were derived from the depth sensitive cosmogenic ratio Xe-131/Xe-126. For the four samples the exposure to cosmic rays in the lunar regolith is described by a two stage exposure model. The history of the four samples was derived in terms of duration and shielding depth of the two stages.

  5. Direct and indirect effects of climate change on soil microbial and soil microbial-plant interactions: What lies ahead?

    DOE PAGESBeta

    Classen, Aimée T.; Sundqvist, Maja K.; Henning, Jeremiah A.; Newman, Gregory S.; Moore, Jessica A. M.; Cregger, Melissa A.; Moorhead, Leigh C.; Patterson, Courtney M.

    2015-08-07

    Global change is altering species distributions and thus interactions among organisms. Organisms live in concert with thousands of other species, some beneficial, some pathogenic, some which have little to no effect in complex communities. Since natural communities are composed of organisms with very different life history traits and dispersal ability it is unlikely they will all respond to climatic change in a similar way. Disjuncts in plant-pollinator and plant-herbivore interactions under global change have been relatively well described, but plant-soil microorganism and soil microbe-microbe relationships have received less attention. Since soil microorganisms regulate nutrient transformations, provide plants with nutrients, allowmore » co-existence among neighbors, and control plant populations, changes in soil microorganism-plant interactions could have significant ramifications for plant community composition and ecosystem function. Finally, in this paper we explore how climatic change affects soil microbes and soil microbe-plant interactions directly and indirectly, discuss what we see as emerging and exciting questions and areas for future research, and discuss what ramifications changes in these interactions may have on the composition and function of ecosystems.« less

  6. Direct and indirect effects of climate change on soil microbial and soil microbial-plant interactions: What lies ahead?

    SciTech Connect

    Classen, Aimée T.; Sundqvist, Maja K.; Henning, Jeremiah A.; Newman, Gregory S.; Moore, Jessica A. M.; Cregger, Melissa A.; Moorhead, Leigh C.; Patterson, Courtney M.

    2015-08-07

    Global change is altering species distributions and thus interactions among organisms. Organisms live in concert with thousands of other species, some beneficial, some pathogenic, some which have little to no effect in complex communities. Since natural communities are composed of organisms with very different life history traits and dispersal ability it is unlikely they will all respond to climatic change in a similar way. Disjuncts in plant-pollinator and plant-herbivore interactions under global change have been relatively well described, but plant-soil microorganism and soil microbe-microbe relationships have received less attention. Since soil microorganisms regulate nutrient transformations, provide plants with nutrients, allow co-existence among neighbors, and control plant populations, changes in soil microorganism-plant interactions could have significant ramifications for plant community composition and ecosystem function. Finally, in this paper we explore how climatic change affects soil microbes and soil microbe-plant interactions directly and indirectly, discuss what we see as emerging and exciting questions and areas for future research, and discuss what ramifications changes in these interactions may have on the composition and function of ecosystems.

  7. SCR and GCR exposure ages of plagioclase grains from lunar soil

    NASA Technical Reports Server (NTRS)

    Etique, P.; Baur, H.; Signer, P.; Wieler, R.

    1986-01-01

    The concentrations of solar wind implanted Ar-36 in mineral grains extracted from lunar soils show that they were exposed to the solar wind on the lunar surface for an integrated time of 10E4 to 10E5 years. From the bulk soil 61501 plagioclase separates of 8 grain size ranges was prepared. The depletion of the implanted gases was achieved by etching aliquot samples of 4 grain sizes to various degrees. The experimental results pertinent to the present discussion are: The spallogenic Ne is, as in most plagioclases from lunar soils, affected by diffusive losses and of no use. The Ar-36 of solar wind origin amounts to (2030 + or - 100) x 10E-8 ccSTP/g in the 150 to 200 mm size fraction and shows that these grains were exposed to the solar wind for at least 10,000 years. The Ne-21/Ne-22 ratio of the spallogenic Ne is 0.75 + or - 0.01 and in very good agreement with the value of this ratio in a plagioclase separate from rock 76535. This rock has had a simple exposure history and its plagioclases have a chemical composition quite similar to those studied. In addition to the noble gases, the heavy particle tracks in an aliquot of the 150 to 200 mm plagioclase separate were investigated and found 92% of the grains to contain more than 10E8 tracks/sq cm. This corresponds to a mean track density of (5 + or - 1) x 10E8 tracks/sq cm. The exploration of the exposure history of the plagioclase separates from the soil 61501 do not contradict the model for the regolith dynamics but also fail to prove it.

  8. Role of Siderophores in Dissimilatory Iron Reduction in Arctic Soils : Effect of Direct Amendment of Siderophores to Arctic Soil

    NASA Astrophysics Data System (ADS)

    Srinivas, A. J.; Dinsdale, E. A.; Lipson, D.

    2014-12-01

    Dissimilatory iron reduction (DIR), where ferric iron (Fe3+) is reduced to ferrous iron (Fe2+) anaerobically, is an important respiratory pathway used by soil bacteria. DIR contributes to carbon dioxide (CO2) efflux from the wet sedge tundra biome in the Arctic Coastal Plain (ACP) in Alaska, and could competitively inhibit the production of methane, a stronger greenhouse gas than CO2, from arctic soils. The occurrence of DIR as a dominant anaerobic process depends on the availability of substantial levels of Fe3+ in soils. Siderophores are metabolites made by microbes to dissolve Fe3+ from soil minerals in iron deficient systems, making Fe3+ soluble for micronutrient uptake. However, as the ACP is not iron deficient, siderophores in arctic soils may play a vital role in anaerobic respiration by dissolving Fe3+ for DIR. We studied the effects of direct siderophore addition to arctic soils through a field study conducted in Barrow, Alaska, and a laboratory incubation study conducted at San Diego State University. In the field experiment, 50μM deferroxamine mesylate (a siderophore), 50μM trisodium nitrilotriacetate (an organic chelator) or an equal volume of water was added to isolated experimental plots, replicated in clusters across the landscape. Fe2+ concentrations were measured in soil pore water samples collected periodically to measure DIR over time in each. In the laboratory experiment, frozen soil samples obtained from drained thaw lake basins in the ACP, were cut into cores and treated with the above-mentioned compounds to the same final concentrations. Along with measuring Fe2+ concentrations, CO2 output was also measured to monitor DIR over time in each core. Experimental addition of siderophores to soils in both the field and laboratory resulted in increased concentrations of soluble Fe3+ and a sustained increase in Fe2+concentrations over time, along with increased respiration rates in siderophore-amended cores. These results show increased DIR in

  9. Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values

    PubMed Central

    Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

    2014-01-01

    Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight–normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. Environ Toxicol Chem 2014

  10. Soil-Root Processes Responsible for Arsenic Uptake in Rice: A Route of Human Exposure

    NASA Astrophysics Data System (ADS)

    Seyfferth, A.; Fendorf, S.

    2010-12-01

    Arsenic contamination of groundwater is causing the largest mass poisoning in history, but we are only beginning to understand the extent of human exposure through contaminated food. Although second to drinking water in terms of human exposure, the consumption of As-laden food, such as rice, can be a significant portion of daily As exposure especially for populations already exposed through drinking water. Arsenic contamination of soils and groundwater is widespread In South and Southeast Asia, which is also one of the largest rice-growing regions of the world. As the demand for food has increased, so too has the use of irrigation practices to meet food demand, and much of this is via water contaminated with arsenic. In order to accurately predict human exposure to arsenic through rice consumption, we must first understand the processes that affect As dynamics in the rhizosphere and thus uptake by rice. Here, we examine As cycling in the rhizosphere, As distribution on and uptake by rice roots, the influence of Fe dynamics on As uptake, and mitigation strategies to reduce concentrations of As in rice grains.

  11. Triclosan exposure reduces thyroxine levels in pregnant and lactating rat dams and in directly exposed offspring.

    PubMed

    Axelstad, Marta; Boberg, Julie; Vinggaard, Anne Marie; Christiansen, Sofie; Hass, Ulla

    2013-09-01

    Thyroid disrupting chemicals can potentially disrupt brain development. Two studies investigating the effect of the antibacterial compound triclosan on thyroxine (T₄) levels in rats are reported. In the first, Wistar rat dams were gavaged with 75, 150 or 300 mg triclosan/kg bw/day throughout gestation and lactation. Total T₄ serum levels were measured in dams and offspring, and all doses of triclosan significantly lowered T₄ in dams, but no significant effects on T₄ levels were seen in the offspring at the end of the lactation period. Since this lack of effect could be due to minimal exposure through maternal milk, a second study using direct per oral pup exposure from postnatal day 3-16 to 50 or 150 mg triclosan/kg bw/day was performed. This exposure pointed to significant T₄ reductions in 16 day old offspring in both dose groups. These results corroborate previous studies showing that in rats lactational transfer of triclosan seems limited. Since an optimal study design for testing potential developmental neurotoxicants in rats, should include exposure during both the pre- and postnatal periods of brain development, we suggest that in the case of triclosan, direct dosing of pups may be the best way to obtain that goal. PMID:23831729

  12. Is tree growth reduction related to direct foliar injuries or soil chemistry modifications?

    PubMed

    Aznar, J-C; Richer-Laflèche, M; Paucar-Muñoz, H; Bordeleau, M; Bégin, Y

    2009-09-01

    In the context of intense emissions causing atmospheric pollution, tree growth reductions could be related to soil chemistry modifications or direct foliar injuries. To verify these hypotheses, mineral soils were sampled in an area (Murdochville, Canada) where previous studies had demonstrated that tree growth was impacted by smelter emissions and that forest floor lead concentrations could be used as a proxy for atmospheric pollutant depositions. Samples were analysed for Al, Pb (concentrations and isotope ratios), basic cations (Ca, K, P, and Mg) and Zr. Mass balance calculations were performed on soil profiles to assess vertical migration of elements. Pb concentrations in litter diminished gradually with distance from the smelter. The Pb isotope ratios in these organic soil layers were close to those measured in the Murdochville ores. These patterns were not encountered in mineral soil layers. Pb isotope ratios in these layers were close to those measured in uncontaminated geological materials, and Pb concentrations and basic cation depletions were not related to the proximity of the smelter. Growth reduction was closely associated with litter Pb concentrations, which were used as a proxy for atmospheric deposition, but was not correlated with any elemental concentration or cation depletion measured in mineral soil layers. Our overall results suggest that trees responded mainly to direct atmospheric emissions, which caused foliar damage, rather than to soil chemistry modifications. PMID:19625068

  13. Direct formation of ZnO nanostructures by chemical solution deposition and EUV exposure.

    PubMed

    Auzelyte, V; Sigg, H; Schmitt, B; Solak, H H

    2010-05-28

    The development of effective methods for the fabrication of ZnO nanostructures is important for the use of this semiconductor material with interesting optical and electronic properties. Chemical solution deposition methods have been demonstrated for creating ZnO films and electron beam exposure of a precursor film, zinc naphthenate, has been shown to yield ZnO nanostructures. Here, we report on the fabrication of ZnO nanostructures with photon beam exposure of a precursor film in the extreme ultraviolet range followed by a high temperature anneal in air. Interference lithography at this wavelength (13.5 nm) led to the production of extremely smooth line/space and dot array type periodic nanostructures with sizes as small as 10 nm. ZnO films obtained through EUV exposure exhibit markedly improved PL spectra with a sharp emission line in the UV range and much suppressed green emission. Electron microscopy and x-ray diffraction measurements also show strong effects of the EUV exposure step in ZnO formation as a function of precursor film thickness, EUV exposure dose and anneal temperature. The use of energetic photons for direct formation of ZnO nanostructures is found to be a method that warrants more investigation for the fabrication of patterned ZnO films with controlled properties. PMID:20431188

  14. Comparisons of direct extraction methods of microbial DNA from different paddy soils.

    PubMed

    Islam, Md Rashedul; Sultana, Tahera; Melvin Joe, M; Cho, Jang-Cheon; Sa, Tongmin

    2012-07-01

    Molecular analyses for the study of soil microbial communities often depend on the direct extraction of DNA from soils. The present work compares the effectiveness of three different methods of extracting microbial DNA from seven different paddy soils. Comparison among different DNA extraction methods against different paddy soil samples revealed a marked variation in DNA yields from 3.18-20.17 μg DNA/g of dry soil. However, irrespective of the soil samples and extraction methods the DNA fragment size was >10 kb. Among the methods evaluated, method-C (chemical-enzymatic-mechanical) had better cell lysis efficiency and DNA yield. After purification of crude DNA by Purification Kit, A260/A230 and A260/A280 ratios of the DNA obtained by method-C reached up to 2.27 and 1.89, respectively, sustaining the efficacy of this technique in removing humic acid, protein and other contaminants. Results of the comprehensive evaluation of DNA extraction methods suggest that method-C is superior to other two methods (chemical-enzymatic and chemical-mechanical), and was the best choice for extraction of total DNA from soil samples. Since soil type and microbial community characteristics influence DNA recovery, this study provides guidance for choosing appropriate extraction and purification methods according to experimental goals. PMID:23961194

  15. Bioavailability of Sodium and Trace Metals under Direct and Indirect Effects of Compost in Urban Soils.

    PubMed

    Kargar, Maryam; Clark, O Grant; Hendershot, William H; Jutras, Pierre; Prasher, Shiv O

    2016-05-01

    The contamination of urban soil with sodium (Na) and trace metals can be one of the major concerns for groundwater contamination and street tree health. The bioavailability of Na, copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in urban soil amended with 0, 5, and 10% w/w compost was evaluated at none, medium, and high contamination levels of soil mixtures. The relationship between soil properties, compost addition, contamination level and metal uptake by barley ( L.) was determined using multivariate linear regression and path analysis. The results indicated the direct negative effect of compost on metal absorption possibly through specific complexation for Cu, Zn, Cd, and Pb. Compost can also affect the absorption of Na and Cd indirectly by means of cation exchange capacity (CEC) and pH. The degree of soil contamination with metals can affect the competition of cations for the complexing sites of the soil mixtures and, therefore, can induce changes in metal availability for plants. Compost addition to the soil also increased nutrient availability, except for ammonium (NH) and nitrate (NO). We concluded that in the short term, the addition of compost significantly reduced metal bioavailability and improved nutrient availability. However, more studies are required to monitor the long-term ability of the compost to reduce Na and trace metal bioavailability in urban soil. PMID:27136168

  16. Exposure to arsenic and lead of children living near a copper-smelter in San Luis Potosi, Mexico: Importance of soil contamination for exposure of children.

    PubMed

    Carrizales, Leticia; Razo, Israel; Téllez-Hernández, Jesús I; Torres-Nerio, Rocío; Torres, Arturo; Batres, Lilia E; Cubillas, Ana-Cristina; Díaz-Barriga, Fernando

    2006-05-01

    The objective of this study was to assess the levels of soil contamination and child exposure in areas next to a primary smelter (arsenic-copper metallurgical) located in the community of Morales in San Luis Potosi, Mexico. In Morales, 90% of the soil samples studied in this work were above 400 mg/kg of lead, and above 100 mg/kg of arsenic, which are guidelines recommended by the United States Environmental Protection Agency (EPA). Bioaccessibility of these metals was studied in vitro in 10 soil samples; the median values of bioaccessibility obtained in these samples were 46.5% and 32.5% for arsenic and lead. Since the concentrations of arsenic and lead in soil were above normal values, and taking into account the bioaccessibility results, exposure to these metals was evaluated in children. Regarding lead, children aged 3-6 years had the highest mean blood lead levels; furthermore, 90% of them had concentrations above 10 microg/dl (CDC's action level). Total urinary arsenic was higher in children aged 8-9 yr; however, the percentage of children with concentrations above 50 microg/g creatinine (CDC's action level) or 100 microg/g creatinine (World Health Organization [WHO] action level) was similar among different age groups. Using the EPAs integrated exposure uptake biokinetic model for lead in children (IEUBK), we estimated that 87% of the total lead in blood is obtained from the soil/dust pathway. The exposure dose to arsenic, estimated for the children living in Morales using Monte Carlo analysis and the arsenic concentrations found in soil, was above the EPA's reference dose. With all these results, it is evident that studies are needed in order to identify adverse health effects in children living in Morales; nevertheless, it is more important to develop a risk reduction program as soon as possible. PMID:16171795

  17. Changes in soil bacterial communities and diversity in response to long-term silver exposure.

    PubMed

    Vasileiadis, Sotirios; Puglisi, Edoardo; Trevisan, Marco; Scheckel, Kirk G; Langdon, Kate A; McLaughlin, Mike J; Lombi, Enzo; Donner, Erica

    2015-10-01

    Silver-induced selective pressure is becoming increasingly important due to the growing use of silver (Ag) as an antimicrobial agent in biomedical and commercial products. With demonstrated links between environmental resistomes and clinical pathogens, it is important to identify microbial profiles related to silver tolerance/resistance. We investigated the effects of ionic Ag stress on soil bacterial communities and identified resistant/persistent bacterial populations. Silver treatments of 50-400 mg Ag kg(-1) soil were established in five soils. Chemical lability measurements using diffusive gradients in thin-film devices confirmed that significant (albeit decreasing) labile Ag concentrations were present throughout the 9-month incubation period. Synchrotron X-ray absorption near edge structure spectroscopy demonstrated that this decreasing lability was due to changes in the Ag speciation to less soluble forms such as Ag(0) and Ag2S. Real-time PCR and Illumina MiSeq screening of 16S rRNA bacterial genes showed β-diversity changes, increasing α-diversity in response to Ag pressure, and immediate and significant reductions in 16S rRNA gene counts with varying degrees of recovery. These effects were more strongly influenced by exposure time than by Ag dose at these rates. Ag-selected dominant OTUs principally resided in known persister taxa (mainly Gram positive), including metal-tolerant bacteria and slow-growing Mycobacteria. PMID:26391377

  18. Microbial community in the soil determines the forest recovery post-exposure to gamma irradiation.

    PubMed

    Shah, Vishal; Shah, Shreya; Mackey, Herman; Kambhampati, Murty; Collins, Daniel; Dowd, Scot E; Colichio, Robert; McDonnell, Kevin T; Green, Timothy

    2013-10-15

    Exposure of an ecosystem to ionizing radiation remains a possibility either due to accidents involving nuclear fuel rods or contamination with high-level radioactive wastes. While the short and long-term effect of ionizing radiation on higher eukaryotes has been well documented, we do not have an understanding on the recovery of the microbial community post radiation. Here we report that at a site within Brookhaven National Laboratory that was radiated from 1961 to 1978 with γ rays (Gamma Forest), the ecosystem has not yet fully recovered from the effects of radiation. The current vegetation type in the Gamma Forest varies as one goes away from the source of ionizing radiation, with the region closest to the source having no vegetation. The microbial tag-encoded FLX amplicon pyrosequencing analysis of the soil from different regions suggests that the current microbial community structure is identical in all the Zones. When soil samples from each vegetation zone of the Gamma Forest were radiated with 1.8 kGy γ radiation and survival microbial community analyzed, clear difference in the microbial communities were observed. It is evident based on the experimental data that the colonization of soil with Nitrosomonadaceae is critical for the higher plants in pine barrens to reestablish and grow after the area had been exposed to ionizing radiation. PMID:24063597

  19. ECa-Directed Soil Sampling for Characterizing Spatial Variability: Monitoring Management- Induced Change

    NASA Astrophysics Data System (ADS)

    Corwin, D. L.

    2006-05-01

    Characterizing spatial variability is an important consideration of any landscape-scale soil-related problem. Geospatial measurements of apparent soil electrical conductivity (ECa) are useful for characterizing spatial variability by directing soil sampling. The objective of this presentation is to discuss equipment, protocols, sampling designs, and a case study of an ECa survey to characterize spatial variability. Specifically, a preliminary spatio-temporal study of management-induced changes to soil quality will be demonstrated for a drainage water reuse study site. The spatio-temporal study used electromagnetic induction ECa data and a response surface sampling design to select 40 sites that reflected the spatial variability of soil properties (i.e., salinity, Na levels, Mo, and B) impacting the intended agricultural use of a saline-sodic field in California's San Joaquin Valley. Soil samples were collected in August 1999 and April 2002. Data from 1999 indicate the presence of high salinity, which increased with depth, high sodium adsorption ratio (SAR), which also increased with depth, and moderate to high B and Mo, which showed no specific trends with depth. The application of drainage water for 32 months resulted in leaching of B from the top 0.3 of soil, leaching of salinity from the top 0.6 m of soil, and leaching of Na and Mo from the top 1.2 m of soil. The leaching fraction over the time period from 1999-2002 was estimated to be 0.10. The level of salinity in the reused drainage water (i.e., 3-5 dS/m) allowed infiltration and leaching to occur even though high sodium and high expanding-lattice clay levels posed potential water flow problems. The leaching of salinity, Na, Mo, and B has resulted in increased forage yield and improved quality of those yields. Preliminary spatio-temporal analyses indicate at least short-term feasibility of drainage water reuse from the perspective of soil quality when the goal is forage production for grazing livestock. The

  20. Do questions reflecting indoor air pollutant exposure from a questionnaire predict direct measure of exposure in owner-occupied houses?

    PubMed

    Loo, C K Jennifer; Foty, Richard G; Wheeler, Amanda J; Miller, J David; Evans, Greg; Stieb, David M; Dell, Sharon D

    2010-08-01

    Home characteristic questions are used in epidemiological studies and clinical settings to assess potentially harmful exposures in the home. The objective of this study was to determine whether questionnaire-reported home characteristics can predict directly measured pollutants. Sixty home inspections were conducted on a subsample of the 2006 population-based Toronto Child Health Evaluation Questionnaire. Indoor/outdoor air and settled dust samples were analyzed. Mean Fel d 1 was higher (p < 0.0001) in homes with a cat (450.58 μg/g) versus without (22.28 μg/g). Mean indoor NO(2) was higher (p = 0.003) in homes with gas stoves (14.98 ppb) versus without (8.31 ppb). Self-reported musty odours predicted higher glucan levels (10554.37 μg/g versus 6308.58 μg/g, p = 0.0077). Der f 1 was predicted by the home's age, but not by reports of carpets, and was higher in homes with mean relative humidity > 50% (61.30 μg/g, versus 6.24 μg/g, p = 0.002). Self-reported presence of a cat, a gas stove, musty odours, mice, and the home's age and indoor relative humidity over 50% predicted measured indoor levels of cat allergens, NO(2), fungal glucan, mouse allergens and dust mite allergens, respectively. These results are helpful for understanding the significance of indoor exposures ascertained by self-reporting in large epidemiological studies and also in the clinical setting. PMID:20948960

  1. Exploring the transfer of recent plant photosynthates to soil microbes: mycorrhizal pathway vs direct root exudation

    PubMed Central

    Kaiser, Christina; Kilburn, Matt R; Clode, Peta L; Fuchslueger, Lucia; Koranda, Marianne; Cliff, John B; Solaiman, Zakaria M; Murphy, Daniel V

    2015-01-01

    Plants rapidly release photoassimilated carbon (C) to the soil via direct root exudation and associated mycorrhizal fungi, with both pathways promoting plant nutrient availability. This study aimed to explore these pathways from the root's vascular bundle to soil microbial communities. Using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging and 13C-phospho- and neutral lipid fatty acids, we traced in-situ flows of recently photoassimilated C of 13CO2-exposed wheat (Triticum aestivum) through arbuscular mycorrhiza (AM) into root- and hyphae-associated soil microbial communities. Intraradical hyphae of AM fungi were significantly 13C-enriched compared to other root-cortex areas after 8 h of labelling. Immature fine root areas close to the root tip, where AM features were absent, showed signs of passive C loss and co-location of photoassimilates with nitrogen taken up from the soil solution. A significant and exclusively fresh proportion of 13C-photosynthates was delivered through the AM pathway and was utilised by different microbial groups compared to C directly released by roots. Our results indicate that a major release of recent photosynthates into soil leave plant roots via AM intraradical hyphae already upstream of passive root exudations. AM fungi may act as a rapid hub for translocating fresh plant C to soil microbes. PMID:25382456

  2. Creating nanoporosity in silver nanocolumns by direct exposure to radio-frequency air plasma

    NASA Astrophysics Data System (ADS)

    El Mel, Abdel-Aziz; Stephant, Nicolas; Hamon, Jonathan; Thiry, Damien; Chauvin, Adrien; Chettab, Meriem; Gautron, Eric; Konstantinidis, Stephanos; Granier, Agnès; Tessier, Pierre-Yves

    2015-12-01

    Nanoporous materials are of great importance for a broad range of applications including catalysis, optical sensors and water filtration. Although several approaches already exist for the creation of nanoporous materials, the race for the development of versatile methods, more suitable for the nanoelectronics industry, is still ongoing. In this communication we report for the first time on the possibility of generating nanoporosity in silver nanocolumns using a dry approach based on the oxidation of silver by direct exposure to a commercially available radio-frequency air plasma. The silver nanocolumns are created by glancing angle deposition using magnetron sputtering of a silver target in pure argon plasma. We show that upon exposure to the rf air plasma, the nanocolumns transform from solid silver into nanoporous silver oxide. We further show that by tuning the plasma pressure and the exposure duration, the oxidation process can be finely adjusted allowing for precisely controlling the morphology and the nanoporosity of the silver oxide nanocolumns. The generation of porosity within the silver nanocolumns is explained according to a cracking-induced oxidation mechanism based on two repeated events occurring alternately during the oxidation process: (i) oxidation of silver upon exposure to the air plasma and (ii) generation of nanocracks and blisters within the oxide layer due to the high internal stress generated within the material during oxidation.

  3. Creating nanoporosity in silver nanocolumns by direct exposure to radio-frequency air plasma.

    PubMed

    El Mel, Abdel-Aziz; Stephant, Nicolas; Hamon, Jonathan; Thiry, Damien; Chauvin, Adrien; Chettab, Meriem; Gautron, Eric; Konstantinidis, Stephanos; Granier, Agnès; Tessier, Pierre-Yves

    2016-01-01

    Nanoporous materials are of great importance for a broad range of applications including catalysis, optical sensors and water filtration. Although several approaches already exist for the creation of nanoporous materials, the race for the development of versatile methods, more suitable for the nanoelectronics industry, is still ongoing. In this communication we report for the first time on the possibility of generating nanoporosity in silver nanocolumns using a dry approach based on the oxidation of silver by direct exposure to a commercially available radio-frequency air plasma. The silver nanocolumns are created by glancing angle deposition using magnetron sputtering of a silver target in pure argon plasma. We show that upon exposure to the rf air plasma, the nanocolumns transform from solid silver into nanoporous silver oxide. We further show that by tuning the plasma pressure and the exposure duration, the oxidation process can be finely adjusted allowing for precisely controlling the morphology and the nanoporosity of the silver oxide nanocolumns. The generation of porosity within the silver nanocolumns is explained according to a cracking-induced oxidation mechanism based on two repeated events occurring alternately during the oxidation process: (i) oxidation of silver upon exposure to the air plasma and (ii) generation of nanocracks and blisters within the oxide layer due to the high internal stress generated within the material during oxidation. PMID:26611109

  4. Validation of the dynamic direct exposure method for toxicity testing of diesel exhaust in vitro.

    PubMed

    Joeng, Lucky; Hayes, Amanda; Bakand, Shahnaz

    2013-01-01

    Diesel exhaust emission is a major health concern because of the complex nature of its gaseous content (e.g., NO2, NO, CO, and CO2) and high concentration of particulate matter (PM) less than 2.5  μ m which allows for deeper penetration into the human pulmonary system upon inhalation. The aim of this research was to elucidate the potential toxic effects of diesel exhaust on a human pulmonary-based cellular system. Validation of a dynamic direct exposure method for both laboratory (230 hp Volvo truck engine) and field (Volkswagen Passat passenger car) diesel engines, at idle mode, was implemented. Human pulmonary type II epithelial cells (A549) grown on porous membranes were exposed to unmodified diesel exhaust at a low flow rate (37.5 mL/min). In parallel, diesel emission sampling was also conducted using real-time air monitoring techniques. Induced cellular effects were assessed using a range of in vitro cytotoxicity assays (MTS, ATP, and NRU). Reduction of cell viability was observed in a time-dependent manner following 30-60 mins of exposure with NRU as the most sensitive assay. The results suggest that the dynamic direct exposure method has the potential to be implemented for both laboratory- and field-based in vitro toxicity studies of diesel exhaust emissions. PMID:23986878

  5. Validation of the Dynamic Direct Exposure Method for Toxicity Testing of Diesel Exhaust In Vitro

    PubMed Central

    Hayes, Amanda; Bakand, Shahnaz

    2013-01-01

    Diesel exhaust emission is a major health concern because of the complex nature of its gaseous content (e.g., NO2, NO, CO, and CO2) and high concentration of particulate matter (PM) less than 2.5 μm which allows for deeper penetration into the human pulmonary system upon inhalation. The aim of this research was to elucidate the potential toxic effects of diesel exhaust on a human pulmonary-based cellular system. Validation of a dynamic direct exposure method for both laboratory (230 hp Volvo truck engine) and field (Volkswagen Passat passenger car) diesel engines, at idle mode, was implemented. Human pulmonary type II epithelial cells (A549) grown on porous membranes were exposed to unmodified diesel exhaust at a low flow rate (37.5 mL/min). In parallel, diesel emission sampling was also conducted using real-time air monitoring techniques. Induced cellular effects were assessed using a range of in vitro cytotoxicity assays (MTS, ATP, and NRU). Reduction of cell viability was observed in a time-dependent manner following 30–60 mins of exposure with NRU as the most sensitive assay. The results suggest that the dynamic direct exposure method has the potential to be implemented for both laboratory- and field-based in vitro toxicity studies of diesel exhaust emissions. PMID:23986878

  6. Exposure to aggressive behaviour and burnout in direct support providers: The role of positive work factors.

    PubMed

    Hensel, Jennifer M; Lunsky, Yona; Dewa, Carolyn S

    2014-11-11

    Many direct support providers (DSPs) are exposed to aggressive behaviour in their work supporting adults with developmental disabilities service recipients. This is a work environment factor that has been linked to job burnout. The objective of this study was to examine the impact of positive work factors on emotional exhaustion (EE) among DSPs who are exposed to aggressive behaviour. Survey responses from 671 DSPs who were working in community service settings for adults with developmental disabilities, and were exposed to aggressive behaviour at least monthly were examined. Hierarchical linear regression examined the direct contribution and moderating role of positive work factors (self-efficacy for dealing with aggression and work contributions) on EE measured with the Maslach Burnout Inventory-Human Services Survey, after controlling for demographics, occupational variables, exposure to aggression and negative emotional reactions to aggression. Results showed that younger age, more experience, more depression/anger emotions in response to aggression, lower self-efficacy and low positive work contributions were significantly associated with EE. Positive work motivation was a moderator of exposure to aggression and EE. When work motivations were low, DSPs were more negatively affected by higher exposure to aggression. These findings suggest that in addition to addressing the negative emotional reactions to the aggressive behaviour encountered at work, it is also important to foster positive work factors which may be protective against EE. PMID:25462500

  7. Exposure to a Rotating Virtual Environment During Treadmill Locomotion Causes Adaptation in Heading Direction

    NASA Technical Reports Server (NTRS)

    Mulavara, A. P.; Richards, J. T.; Marshburn, A.; Nomura, Y.; Bloomberg, J. J.

    2005-01-01

    The goal of the present study was to investigate the adaptive effects of variation in the direction of optic flow, experienced during linear treadmill walking, on modifying locomotor trajectory. Subjects (n = 30) walked on a motorized linear treadmill at 4.0 km/h for 24 minutes while viewing the interior of a 3D virtual scene projected onto a screen 1.5 m in front of them. The virtual scene depicted constant self-motion equivalent to either 1) walking around the perimeter of a room to one s left (Rotating Room group) 2) walking down the center of a hallway (Infinite Hallway group). The scene was static for the first 4 minutes, and then constant rate self-motion was simulated for the remaining 20 minutes. Before and after the treadmill locomotion adaptation period, subjects performed five stepping trials where in each trial they marched in place to the beat of a metronome at 90 steps/min while blindfolded in a quiet room. The subject s final heading direction (deg), final X (for-aft, cm) and final Y (medio-lateral, cm) positions were measured for each trial. During the treadmill locomotion adaptation period subject s 3D torso position was measured. We found that subjects in the Rotating Room group as compared to the Infinite Hallway group: 1) showed significantly greater deviation during post exposure testing in the heading direction and Y position opposite to the direction of optic flow experienced during treadmill walking 2) showed a significant monotonically increasing torso yaw angular rotation bias in the direction of optic flow during the treadmill adaptation exposure period. Subjects in both groups showed greater forward translation (in the +X direction) during the post treadmill stepping task that differed significantly from their pre exposure performance. Subjects in both groups reported no perceptual deviation in position during the stepping tasks. We infer that 3 viewing simulated rotary self-motion during treadmill locomotion causes adaptive modification

  8. Exposure to a Rotating Virtual Environment During Treadmill Locomotion Causes Adaptation in Heading Direction

    NASA Technical Reports Server (NTRS)

    Ruttley, T; Marshburn, A.; Bloomberg, J. J.; Mulavara, A. P.; Richards, J. T.; Nomura, Y.

    2005-01-01

    The goal of the present study was to investigate the adaptive effects of variation in the direction of optic flow, experienced during linear treadmill walking, on modifying locomotor trajectory. Subjects (n = 30) walked on a motorized linear treadmill at 4.0 kilometers per hour for 24 minutes while viewing the interior of a 3D virtual scene projected onto a screen 1.5 in in front of them. The virtual scene depicted constant self-motion equivalent to either 1) walking around the perimeter of a room to one s left (Rotating Room group) 2) walking down the center of a hallway (Infinite Hallway group). The scene was static for the first 4 minutes, and then constant rate self-motion was simulated for the remaining 20 minutes. Before and after the treadmill locomotion adaptation period, subjects performed five stepping trials where in each trial they marched in place to the beat of a metronome at 90 steps/min while blindfolded in a quiet room. The subject's final heading direction (deg), final X (for-aft, cm) and final Y (medio-lateral, cm) positions were measured for each trial. During the treadmill locomotion adaptation period subject's 3D torso position was measured. We found that subjects in the Rotating Room group as compared to the Infinite Hallway group: 1) showed significantly greater deviation during post exposure testing in the heading direction and Y position opposite to the direction of optic flow experienced during treadmill walking 2) showed a significant monotonically increasing torso yaw angular rotation bias in the direction of optic flow during the treadmill adaptation exposure period. Subjects in both groups showed greater forward translation (in the +X direction) during the post treadmill stepping task that differed significantly from their pre exposure performance. Subjects in both groups reported no perceptual deviation in position during the stepping tasks. We infer that viewing simulated rotary self-motion during treadmill locomotion causes

  9. SOIL ORGANIC CARBON: BENEFITS OF DIRECT SEEDING TO PRODUCTIVITY AND ENVIRONMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural carbon (C) sequestration may be one of the most cost effective ways to slow the processes of global warming. Direct seeding aims to conserve, improve and make more efficient use of natural resources through integrated management of available soil, water and biological resources. Numerou...

  10. Estimation of NH3 Bi-Directional Flux from Managed Agricultural Soils

    EPA Science Inventory

    The Community Multi-Scale Air Quality model (CMAQ v4.7) contains a bi-directional ammonia (NH3) flux option that computes emission and deposition of ammonia derived from commercial fertilizer via a temperature dependent parameterization of canopy and soil compensation ...

  11. Comparison of model- and design-based sampling strategies for characterizing spatial variablity with ECa-directed soil sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial variability has a profound influence on solute transport in the vadose zone, soil quality assessment, and site-specific crop management. Directed soil sampling based on geospatial measurements of apparent soil electrical conductivity (ECa) is a potential means of characterizing the spatial ...

  12. Quantitation of Aristolochic Acids in Corn, Wheat Grain, and Soil Samples Collected in Serbia: Identifying a Novel Exposure Pathway in the Etiology of Balkan Endemic Nephropathy.

    PubMed

    Chan, Wan; Pavlović, Nikola M; Li, Weiwei; Chan, Chi-Kong; Liu, Jingjing; Deng, Kailin; Wang, Yinan; Milosavljević, Biljana; Kostić, Emina N

    2016-07-27

    While to date investigations provided convincing evidence on the role of aristolochic acids (AAs) in the etiology of Balkan endemic nephropathy (BEN) and upper urothelial cancer (UUC), the exposure pathways by which AAs enter human bodies to cause BEN and UUC remain obscure. The goal of this study is to test the hypothesis that environmental pollution by AAs and root uptake of AAs in the polluted soil may be one of the pathways by which AAs enter the human food chain. The hypothesis driving this study was that the decay of Aristolochia clematitis L., a AA-containing herbaceous plant that is found growing widespread in the endemic regions, could release free AAs to the soil, which could be taken up by food crops growing nearby, thereby transferring this potent human nephrotoxin and carcinogen into their edible parts. Using the highly sensitive and selective high-performance liquid chromatography coupled with fluorescence detection method, we identified and quantitated in this study for the first time AAs in corn, wheat grain, and soil samples collected from the endemic village Kutles in Serbia. Our results provide the first direct evidence that food crops and soil in the Balkans are contaminated with AAs. It is possible that the presence of AAs in edible parts of crops originating from the AA-contaminated soil could be one of the major pathways by which humans become exposed to AAs. PMID:27362729

  13. In vitro particulate matter exposure causes direct and lung-mediated indirect effects on cardiomyocyte function.

    PubMed

    Gorr, Matthew W; Youtz, Dane J; Eichenseer, Clayton M; Smith, Korbin E; Nelin, Timothy D; Cormet-Boyaka, Estelle; Wold, Loren E

    2015-07-01

    Particulate matter (PM) exposure induces a pathological response from both the lungs and the cardiovascular system. PM is capable of both manifestation into the lung epithelium and entrance into the bloodstream. Therefore, PM has the capacity for both direct and lung-mediated indirect effects on the heart. In the present studies, we exposed isolated rat cardiomyocytes to ultrafine particulate matter (diesel exhaust particles, DEP) and examined their contractile function and calcium handling ability. In another set of experiments, lung epithelial cells (16HBE14o- or Calu-3) were cultured on permeable supports that allowed access to both the basal (serosal) and apical (mucosal) media; the basal media was used to culture cardiomyocytes to model the indirect, lung-mediated effects of PM on the heart. Both the direct and indirect treatments caused a reduction in contractility as evidenced by reduced percent sarcomere shortening and reduced calcium handling ability measured in field-stimulated cardiomyocytes. Treatment of cardiomyocytes with various anti-oxidants before culture with DEP was able to partially prevent the contractile dysfunction. The basal media from lung epithelial cells treated with PM contained several inflammatory cytokines, and we found that monocyte chemotactic protein-1 was a key trigger for cardiomyocyte dysfunction. These results indicate the presence of both direct and indirect effects of PM on cardiomyocyte function in vitro. Future work will focus on elucidating the mechanisms involved in these separate pathways using in vivo models of air pollution exposure. PMID:25957217

  14. Occupational exposure to base stations-compliance with EU directive 2004/40/EC.

    PubMed

    Gajsek, Peter; Simunić, Dina

    2006-01-01

    The rapid growth of mobile communications has not only led to a rising number of mobile telephones. It has also made base stations essential for these services widespread on many roofs. However, not everyone is aware that working close to sources of high frequency electromagnetic fields (EMF), such as transmitter antennas for mobile phones, pagers and police, fire and other emergency services, can result in high EMF exposure. This paper deals with measurements and calculations of the compliance boundary for workers in one typical roof top base station setting according to EU Directive and other relevant EN standards. PMID:16790176

  15. Health risk assessment of urban population exposure to contaminants in the soils of the Southern Kuzbass

    NASA Astrophysics Data System (ADS)

    Osipova, N. A.; Tarasova, N. P.; Osipov, K. Yu.; Maximova, D. I.

    2015-11-01

    This study concerns the human health risk due to exposure of Co, Cu, As, Mn contained in soils of the Southern Kuzbass, where the coal industry is developed. Soil samples of 200 were taken in Mezhdurechensk - city with intensive coal mining and processing industries. The content of heavy metals in samples were determined using the electron spectroscopy. Several samples were also investigated by methods of the instrumental neutron activation analysis (INAA) and the inductively coupled plasma mass spectrometry (ICP-MS). With regard to the effects of heavy metals on the adult population health the total Hazard Index (HI) for ingestion and inhalation routes was 0.87×10-1 and 7.8×10-1 respectively. According to the contribution of Co, Cu, As, Mn to the total HI the elements form the decreasing series Mn (0,42-0,50)> Co (0.18-0.20)> Cu (0,13-0,19 )> As (0,05-0,09). These chemical elements are present in the organic and inorganic forms in coals and coal wastes. Ranking the city territory has shown that administrative districts have different HI values (8.4 10-1 - 8.8 10-1). When analyzing the human health risks of coal mining and coal-processing enterprises the impact of heavy metals as components of coals and combustion products should be taken into account.

  16. Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic

    PubMed Central

    Cory, Rose M.; Crump, Byron C.; Dobkowski, Jason A.; Kling, George W.

    2013-01-01

    Recent climate change has increased arctic soil temperatures and thawed large areas of permafrost, allowing for microbial respiration of previously frozen C. Furthermore, soil destabilization from melting ice has caused an increase in thermokarst failures that expose buried C and release dissolved organic C (DOC) to surface waters. Once exposed, the fate of this C is unknown but will depend on its reactivity to sunlight and microbial attack, and the light available at the surface. In this study we manipulated water released from areas of thermokarst activity to show that newly exposed DOC is >40% more susceptible to microbial conversion to CO2 when exposed to UV light than when kept dark. When integrated over the water column of receiving rivers, this susceptibility translates to the light-stimulated bacterial activity being on average from 11% to 40% of the total areal activity in turbid versus DOC-colored rivers, respectively. The range of DOC lability to microbes seems to depend on prior light exposure, implying that sunlight may act as an amplification factor in the conversion of frozen C stores to C gases in the atmosphere. PMID:23401500

  17. Engineered nanomaterials in water and soils: a risk quantification based on probabilistic exposure and effect modeling.

    PubMed

    Gottschalk, Fadri; Kost, Elias; Nowack, Bernd

    2013-06-01

    The production and use of engineered nanomaterials (ENMs) are increasing rapidly, and therefore, the need to assess their environmental exposure and associated risks has become increasingly important. Only a handful of studies have quantified the release and environmental concentrations of ENMs, but much work has been done to investigate the effects of these materials on organisms. The aim of the present study was to quantify probabilistically the environmental risks of ENMs, producing species sensitivity distributions that were then compared with probability distributions of predicted environmental concentrations. Five nanomaterials (nano-Ag, nano-TiO2 , nano-ZnO, carbon nanotubes [CNTs], and fullerenes) and 4 environmental compartments (surface water, sewage treatment plant effluents, soils, and sludge-treated soils) were considered. From 60 ecotoxicological studies, the authors extracted 112 single values to work with (25 values in 13 studies for nano-Ag, 17 values in 10 studies for CNTs, 7 values in 7 studies for fullerenes, 34 values in 23 studies for nano-TiO2 , and 29 values in 17 studies for nano-ZnO). The results indicate there is only a marginal risk for these metal-based nanomaterials in surface water (0.7% risk for nano-Ag and <0.1% for nano-TiO2 ) and some risk in sewage treatment plant effluents (nano-Ag 39.7%, nano-TiO2 18.7%, and nano-ZnO 1.1%). Apart from a marginal value of <0.1% for nano-TiO2 in sludge-treated soils, no risk from the other evaluated ENMs in terrestrial compartments is currently predicted. The discussion of the results considers the influence of the effects of different forms of 1 ENM (coating, agglomeration state, and mineralogy), the test conditions (dissolution and agglomeration), and transformation reactions. PMID:23418073

  18. Dust and nutrient enrichment by wind erosion from Danish soils in dependence of tillage direction

    NASA Astrophysics Data System (ADS)

    Mohammadian Behbahani, Ali; Fister, Wolfgang; Heckrath, Goswin; Kuhn, Nikolaus J.

    2016-04-01

    Wind erosion is a selective process, which promotes erosion of fine particles. Therefore, it can be assumed that increasing erosion rates are generally associated with increasing loss of dust sized particles and nutrients. However, this selective process is strongly affected by the orientation and respective trapping efficiency of tillage ridges and furrows. Since tillage ridges are often the only protection measure available on poorly aggregated soils in absence of a protective vegetation cover, it is very important to know which orientation respective to the dominant wind direction provides best protection. This knowledge could be very helpful for planning erosion protection measures on fields with high wind erosion susceptibility. The main objective of this study, therefore, was to determine the effect of tillage direction on dust and nutrient mobilization by wind, using wind tunnel simulations. In order to assess the relationship between the enrichment ratio of specific particle sizes and the amount of eroded nutrients, three soils with loamy sand texture, but varying amounts of sand-sized particles, were selected. In addition, a soil with slightly less sand, but much higher organic matter content was chosen. The soils were tested with three different soil surface scenarios - flat surface, parallel tillage, perpendicular tillage. The parallel tillage operation experienced the greatest erosion rates, independent of soil type. Particles with D50 between 100-155 μm showed the greatest risk of erosion. However, due to a greater loss of dust sized particles from perpendicularly tilled surfaces, this wind-surface arrangement showed a significant increase in nutrient enrichment ratio compared to parallel tillage and flat surfaces. The main reason for this phenomenon is most probably the trapping of larger particles in the perpendicular furrows. This indicates that the highest rate of soil protection does not necessarily coincide with lowest soil nutrient losses and

  19. Direct detection of 16S rRNA in soil extracts by using oligonucleotide microarrays.

    PubMed

    Small, J; Call, D R; Brockman, F J; Straub, T M; Chandler, D P

    2001-10-01

    We report on the development and validation of a simple microarray method for the direct detection of intact 16S rRNA from unpurified soil extracts. Total RNAs from Geobacter chapellei and Desulfovibrio desulfuricans were hybridized to an oligonucleotide array consisting of universal and species-specific 16S rRNA probes. PCR-amplified products from Geobacter and Desulfovibrio were easily and specifically detected under a range of hybridization times, temperatures, and buffers. However, reproducible, specific hybridization and detection of intact rRNA could be accomplished only by using a chaperone-detector probe strategy. With this knowledge, assay conditions were developed for rRNA detection using a 2-h hybridization time at room temperature. Hybridization specificity and signal intensity were enhanced using fragmented RNA. Formamide was required in the hybridization buffer in order to achieve species-specific detection of intact rRNA. With the chaperone detection strategy, we were able to specifically hybridize and detect G. chapellei 16S rRNA directly from a total-RNA soil extract, without further purification or removal of soluble soil constituents. The detection sensitivity for G. chapellei 16S rRNA in soil extracts was at least 0.5 microg of total RNA, representing approximately 7.5 x 10(6) Geobacter cell equivalents of RNA. These results suggest that it is now possible to apply microarray technology to the direct detection of microorganisms in environmental samples, without using PCR. PMID:11571176

  20. Wearable real-time direct reading naphthalene and VOC personal exposure monitor

    NASA Astrophysics Data System (ADS)

    Hug, W. F.; Bhartia, R.; Reid, R. D.; Reid, M. R.; Oswal, P.; Lane, A. L.; Sijapati, K.; Sullivan, K.; Hulla, J. E.; Snawder, J.; Proctor, S. P.

    2012-06-01

    Naphthalene has been identified by the National Research Council as a serious health hazard for personnel working with jet fuels and oil-based sealants containing naphthalene. We are developing a family of miniature, self-contained, direct reading personal exposure monitors (PEMs) to detect, differentiate, quantify, and log naphthalene and other volatile organic compounds (VOCs) in the breathing zone of the wearer or in the hands of an industrial hygienist with limits of detection in the low parts per billion (ppb) range. The VOC Dosimeter (VOCDos) described here is a PEM that provides real-time detection and data logging of exposure as well as accumulated dose, with alarms addressing long term and immediate exposure limits. We will describe the sensor, which employs optical methods with a unique excitation source and rapidly refreshable vapor concentrator. This paper addresses the rapidly increasing awareness of the health risks of inhaling jet fuel vapors by Department of Defense (DOD) personnel engaged in or around jet fueling operations. Naphthalene is a one to three percent component of the 5 billion gallons of jet fuels used annually by DOD. Naphthalene is also a component of many other petroleum products such as asphalt and other oil-based sealants. The DOD is the single largest user of petroleum fuels in the United States (20% of all petroleum fuel used). The VOCDos wearable sensor provides real-time detection and data logging of exposure as well as accumulated dose. We will describe the sensor, which employs endogenous fluorescence from VOCs accumulated on a unique, rapidly refreshable, patent-pending concentrator, excited by a unique deep ultraviolet excitation source.

  1. Evidence of the direct adsorption of mercury in human hair during occupational exposure to mercury vapour.

    PubMed

    Queipo Abad, Silvia; Rodríguez-González, Pablo; García Alonso, J Ignacio

    2016-07-01

    We have found clear evidence of direct adsorption of mercury in human hair after the occupational exposure to mercury vapour. We have performed both longitudinal analysis of human hair by laser ablation ICP-MS and speciation analysis by gas chromatography ICP-MS in single hair strands of 5 individuals which were occupationally exposed to high levels of mercury vapour and showed acute mercury poisoning symptoms. Hair samples, between 3.5 and 11cm long depending on the individual, were taken ca. three months after exposure. Single point laser ablation samples of 50μm diameter were taken at 1mm intervals starting from the root of the hairs. Sulfur-34 was used as internal standard. The ratio (202)Hg/(34)S showed a distinct pattern of mercury concentration with much lower levels of mercury near the root of the hair and high levels of mercury near the end of the hair. In all cases a big jump in the concentration of mercury in hair occurred at a given distance from the root, between 32 and 42mm depending on the individual, with a high and almost constant concentration of mercury for longer distances to the root. When we took into account the rate of hair growth in humans, 9-15mm/month, the jump in mercury concentration agreed approximately with the dates when the contamination occurred with the new growing hair showing much lower mercury concentration. In some cases the concentration of mercury at the tip of the hair was ca. 1000 times higher than that near the root. Additionally, speciation studies confirmed that mercury in all hair samples was present as inorganic mercury. The only explanation for these results was the direct adsorption of mercury vapour in hair at the time of exposure. PMID:27259347

  2. Infant and Early Childhood Exposure to Adult-Directed and Child-Directed Television Programming: Relations with Cognitive Skills at Age Four

    ERIC Educational Resources Information Center

    Barr, Rachel; Lauricella, Alexis; Zach, Elizabeth; Calvert, Sandra L.

    2010-01-01

    This study described the relations among the amount of child-directed versus adult-directed television exposure at ages 1 and 4 with cognitive outcomes at age 4. Sixty parents completed 24-hour television diaries when their children were 1 and 4 years of age. At age 4, their children also completed a series of cognitive measures and parents…

  3. Exposure Time to Lethal Temperatures for Meloidogyne incognita Suppression and Its Implication for Soil Solarization.

    PubMed

    Wang, K-H; McSorley, R

    2008-03-01

    Meloidogyne incognita eggs or J2 were incubated in test tubes containing sand:peat mix and immersed in a water bath heated to 38, 39, 40, 41, 42, 43, 44 and 45 degrees C for a series of time intervals. Controls were maintained at 22 degrees C. Nematodes surviving or hatching were collected from Baermann trays after three weeks of incubation. Regression analyses between percent survival or egg hatch and hours of heat treatment were performed for each temperature. Complete suppression of egg hatch required 389.8, 164.5, 32.9, 19.7 and 13.1 hours at 38, 39, 40, 41 and 42 degrees C, respectively. Complete killing of J2 required 47.9, 46.2, 17.5 and 13.8 hours at 39, 40, 41 and 42 degrees C, respectively. J2 were not completely killed at 38 degrees C within 40 hours of treatment, but were killed within one hour at 44 and 45 degrees C. Effect of temperature on nematode killing is not determined by heat units. Oscillating temperature between cool and warm did not interfere with the nematode suppressive effect by the heat treatment. Six-week solarization in the field during the summers of 2003 and 2004 in Florida accumulated heat exposure times in the top 15 cm of soil that surpassed levels required to kill M. incognita as determined in the water bath experiments. Although near zero M. incognita were detected right after solarization, the nematode population densities increased after a cycle of a susceptible pepper crop. Therefore, future research should address failure of solarization to kill nematodes in the deeper soil layers. PMID:19259512

  4. Exposure Time to Lethal Temperatures for Meloidogyne incognita Suppression and Its Implication for Soil Solarization

    PubMed Central

    Wang, K.-H.; McSorley, R.

    2008-01-01

    Meloidogyne incognita eggs or J2 were incubated in test tubes containing sand:peat mix and immersed in a water bath heated to 38, 39, 40, 41, 42, 43, 44 and 45°C for a series of time intervals. Controls were maintained at 22°C. Nematodes surviving or hatching were collected from Baermann trays after three weeks of incubation. Regression analyses between percent survival or egg hatch and hours of heat treatment were performed for each temperature. Complete suppression of egg hatch required 389.8, 164.5, 32.9, 19.7 and 13.1 hours at 38, 39, 40, 41 and 42°C, respectively. Complete killing of J2 required 47.9, 46.2, 17.5 and 13.8 hours at 39, 40, 41 and 42°C, respectively. J2 were not completely killed at 38°C within 40 hours of treatment, but were killed within one hour at 44 and 45°C. Effect of temperature on nematode killing is not determined by heat units. Oscillating temperature between cool and warm did not interfere with the nematode suppressive effect by the heat treatment. Six-week solarization in the field during the summers of 2003 and 2004 in Florida accumulated heat exposure times in the top 15 cm of soil that surpassed levels required to kill M. incognita as determined in the water bath experiments. Although near zero M. incognita were detected right after solarization, the nematode population densities increased after a cycle of a susceptible pepper crop. Therefore, future research should address failure of solarization to kill nematodes in the deeper soil layers. PMID:19259512

  5. Rapid monitoring of soil, water, and air dusts by direct large-area alpha spectrometry.

    PubMed

    Sill, C W

    1995-07-01

    During retrieval and disposition of wastes containing transuranium elements, continuous monitoring of the air, water, and soil for alpha emitters was required to ensure that safety limits were not exceeded and that the waste itself was not disturbed unknowingly. Direct measurements by alpha spectrometry were particularly promising because of their potential speed, sensitivity, and their ability to identify transuranium radionuclides under field conditions. Soil samples or settled dusts were finely ground, suspended in 80% ethanol, sprayed onto circular stainless steel pans, and dried on a hotplate. Water samples were mounted directly by spraying. Air dusts were collected with a high-volume air sampler on 20- by 25-cm membrane filters. The samples were then analyzed directly in a large pressurized gridded ionization chamber without further sample preparation. The lower limits of detection for 10-min counting times were 1.5 Bq g-1 (40 pCi g-1) for 100-mg soil samples, and 4 x 10(-2) Bq m-3 (10(-12) microCi mL-1) for a 10-min air sample taken at 0.4 m3 min-1 (14 cubic feet per minute) and counted without waiting for decay of radon progeny. PMID:7790211

  6. Comparison of direct measurement methods for headset noise exposure in the workplace

    PubMed Central

    Nassrallah, Flora G.; Giguère, Christian; Dajani, Hilmi R.; Ellaham, Nicolas N.

    2016-01-01

    The measurement of noise exposure from communication headsets poses a methodological challenge. Although several standards describe methods for general noise measurements in occupational settings, these are not directly applicable to noise assessments under communication headsets. For measurements under occluded ears, specialized methods have been specified by the International Standards Organization (ISO 11904) such as the microphone in a real ear and manikin techniques. Simpler methods have also been proposed in some national standards such as the use of general purpose artificial ears and simulators in conjunction with single number corrections to convert measurements to the equivalent diffuse field. However, little is known about the measurement agreement between these various methods and the acoustic manikin technique. Twelve experts positioned circum-aural, supra-aural and insert communication headsets on four different measurement setups (Type 1, Type 2, Type 3.3 artificial ears, and acoustic manikin). Fit-refit measurements of four audio communication signals were taken under quiet laboratory conditions. Data were transformed into equivalent diffuse-field sound levels using third-octave procedures. Results indicate that the Type 1 artificial ear is not suited for the measurement of sound exposure under communication headsets, while Type 2 and Type 3.3 artificial ears are in good agreement with the acoustic manikin technique. Single number corrections were found to introduce a large measurement uncertainty, making the use of the third-octave transformation preferable. PMID:26960783

  7. Comparison of direct measurement methods for headset noise exposure in the workplace.

    PubMed

    Nassrallah, Flora G; Giguere, Christian; Dajani, Hilmi R; Ellaham, Nicolas N

    2016-01-01

    The measurement of noise exposure from communication headsets poses a methodological challenge. Although several standards describe methods for general noise measurements in occupational settings, these are not directly applicable to noise assessments under communication headsets. For measurements under occluded ears, specialized methods have been specified by the International Standards Organization (ISO 11904) such as the microphone in a real ear and manikin techniques. Simpler methods have also been proposed in some national standards such as the use of general purpose artificial ears and simulators in conjunction with single number corrections to convert measurements to the equivalent diffuse field. However, little is known about the measurement agreement between these various methods and the acoustic manikin technique. Twelve experts positioned circum-aural, supra-aural and insert communication headsets on four different measurement setups (Type 1, Type 2, Type 3.3 artificial ears, and acoustic manikin). Fit-refit measurements of four audio communication signals were taken under quiet laboratory conditions. Data were transformed into equivalent diffuse-field sound levels using third-octave procedures. Results indicate that the Type 1 artificial ear is not suited for the measurement of sound exposure under communication headsets, while Type 2 and Type 3.3 artificial ears are in good agreement with the acoustic manikin technique. Single number corrections were found to introduce a large measurement uncertainty, making the use of the third-octave transformation preferable. PMID:26960783

  8. 1H NMR metabolomics of earthworm responses to polychlorinated biphenyl (PCB) exposure in soil.

    PubMed

    Whitfield Åslund, Melissa L; Simpson, André J; Simpson, Myrna J

    2011-06-01

    (1)H NMR-based metabolomics was used to examine the metabolic profile of D(2)O-buffer extracted tissues of Eisenia fetida earthworms exposed for 2 days to an artificial soil spiked with sub-lethal concentrations of polychlorinated biphenyls (PCBs) (0, 0.5, 1, 5, 10, or 25 mg/kg Aroclor 1254). Univariate statistical analysis of the identified metabolites revealed a significant increase in ATP concentration in earthworms exposed to the highest soil PCB concentration, but detected no significant changes in other metabolites. However, a multivariate approach which considers alterations in multiple metabolites simultaneously, identified a significant linear relationship between earthworm metabolic profiles and PCB concentration (cross-validated PLS-regression with 7 components, R(2)X = 0.99, R(2)Y = 0.77, Q(2)Y = 0.45, P < 0.001). Significant changes in pair-wise metabolic correlations were also detected as PCB concentration increased. For example, lysine and ATP concentrations showed no apparent correlation in control earthworms (r = 0.22, P = 0.54), but were positively correlated in earthworms from the 25 mg/kg treatment (r = 0.87, P = 0.001). Overall, the observed metabolic responses suggest that PCBs disrupted both carbohydrate (energy) metabolism and membrane (osmolytic) function in E. fetida. The ability of (1)H NMR-based metabolomics to detect these responses suggests that this method offers significant potential for direct assessment of sub-lethal PCB toxicity in soil. PMID:21424327

  9. Rote learning after exposure to a direct-to-consumer television advertisement for a prescription drug.

    PubMed

    Schommer, J C; Doucette, W R; Mehta, B H

    1998-01-01

    The purpose of this exploratory study was to: (1) test the rote learning response; and (2) investigate the effects of selected consumer demographic/psychographic, information-access, and health-related knowledge/experience variables on rote learning after exposure to a televised direct-to-consumer prescription drug advertisement that was developed and broadcast under new US Food and Drug Administration guidelines. A judgment (nonprobability) sample of 202 individuals waiting for their appointments at a university-based general medicine clinic was selected to view a televised advertisement and complete a questionnaire. One participant returned an unusable form; 24 others held positions in health care occupations and were omitted from the analysis. Results based on responses from the 177 eligible participants showed that the presentation of both promotional and risk-related product information in the same broadcast advertisement may lead to viewer problems with rote learning of each type of information. PMID:9663375

  10. Protocols and guidelines for field-scale measurement of soil salinity distribution with ECa-directed soil sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil salinity is a spatially complex and dynamic property of soil that influences crop yields when the threshold salinity level is exceeded. The mapping and monitoring of soil salinity is necessary for reclamation, crop selection, and site-specific irrigation management of salt-affected soils in th...

  11. Effects of soil and dietary exposures to Ag nanoparticles and AgNO₃ in the terrestrial isopod Porcellionides pruinosus.

    PubMed

    Tourinho, Paula S; van Gestel, Cornelis A M; Jurkschat, Kerstin; Soares, Amadeu M V M; Loureiro, Susana

    2015-10-01

    The effects of Ag-NPs and AgNO3 on the isopod Porcellionides pruinosus were determined upon soil and dietary exposures. Isopods avoided Ag in soil, with EC50 values of ∼16.0 and 14.0 mg Ag/kg for Ag-NPs and AgNO3, respectively. Feeding inhibition tests in soil showed EC50s for effects on consumption ratio of 127 and 56.7 mg Ag/kg, respectively. Although similar EC50s for effects on biomass were observed for nanoparticulate and ionic Ag (114 and 120 mg Ag/kg dry soil, respectively), at higher concentrations greater biomass loss was found for AgNO3. Upon dietary exposure, AgNO3 was more toxic, with EC50 for effects on biomass change being >1500 and 233 mg Ag/kg for Ag-NPs and AgNO3, respectively. The difference in toxicity between Ag-NPs and AgNO3 could not be explained from Ag body concentrations. This suggests that the relation between toxicity and bioavailability of Ag-NPs differs from that of ionic Ag in soils. PMID:26071943

  12. Alluvial and riparian soils as major sources of lead exposure in young children in the Philippines: the role of floods.

    PubMed

    Ostrea, Enrique M; Ostrea, Angelo M; Villanueva-Uy, Ma Esterlita; Chiodo, Lisa; Janisse, James

    2015-04-01

    The objective of this paper was to determine the prevalence and sources of high lead (Pb) exposure among children in Bulacan, Philippines. A total of 150 children (6-7 years old) and their caregivers were studied. Lead was analyzed in children hair and deciduous teeth. Sources of lead exposure were determined by caregiver interview and Pb analysis of house soil, drinking faucet water, air, and water from seven Bulacan rivers. Lead was positive in 91.3% of children's hair (MC or median concentration = 8.9 μg/g; range = 0-38.29), in 46.2% of the teeth (MC = 0.000 μg/mg in positive samples; range = 0.00-0.020), in 100% of soil (MC = 27.06 mg/kg; range = 3.05-1155.80), in 21.1% of air (MC = 0 μg/Ncm; range = 0-0.10), in 4% of house, faucet water (MC = 0.0 ppm; range = 0-40). There was a significant correlation (Spearman's rho) between Pb in children's hair and soil (r = 0.195; p = 0.017) and between Pb in house water and outdoor air (r = 0.616; p = 0.005). There is no significant correlation between Pb in children's hair and teeth. None of the potential sources of Pb from interview were related to lead exposure in the children. Water from seven Bulacan rivers was 100% positive for lead (MC = 70.00 ppb; range = 30-90). Widespread flooding with river overflow occurred in Bulacan in 2009 which likely caused lead contamination of the soil. There was no significant difference in the lead concentration of the soil whether near or far from the river (p = 0.205, Mann-Whitney U test). High lead exposure in children in Bulacan is likely from soil contaminated by lead-polluted rivers during flooding. In areas where flooding is common, alluvial and riparian soils from polluted rivers are important sources of lead exposure in children. PMID:25501640

  13. Rapid mortality of pest arthropods by direct exposure to a dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Bures, Brian Lee

    The spread of arthropods due to trade of agricultural commodities and travel of humans is a significant problem in many countries. Limiting the movement of pest species is commonly achieved by the use of chemical pesticides at quarantine facilities. One potential alternative to chemical pesticides is direct exposure of contaminated commodities to ambient pressure electrical discharges. The arthropods are directly exposed to a 5.0 cm helium discharge with power densities on the order of 60 mW/cm3. Direct measurement of chemical species and ambient gas temperature shows the DBD treatment remains effective when the chemically reactive species are suppressed by helium, and when the ambient gas temperature of the discharge is below 40°C. In addition to gas temperature measurements and chemical species identification, the electron temperature and electron density were measured using the neutral bremsstrahlung continuum technique. This study is the first successful implementation of the neutral bremsstrahlung continuum emission diagnostic to a barrier discharge. The primary advantages of the diagnostic for barrier discharges are the measurement is passive and the spatial resolution is only limited by the collimation of the light and the sensitivity of the detector. Although the electron temperature (1.0--1.5 eV) and electron density (˜108 cm-3) are modest, non-chemical dielectric barrier discharge (DBD) treatment of arthropods has proven effective in significantly reducing the population of some arthropods including human body lice, green peach aphids, and western flower thrips. However, the treatment was not universally effective on all arthropod species. German cockroaches and citrus mealy bugs showed substantial resistance to the treatment. The study has shown the treatment does not always induce instant mortality: however, the mortality increases over a 24 hr-period after treatment. Based upon visual observation and the time after treatment to reach maximum

  14. A model for inferring canopy and underlying soil temperatures from multi-directional measurements

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Brakke, T. W.; Susskind, J.

    1992-01-01

    A model is presented of thermal emission from a canopy/soil surface, where the soil and the leaves are at different temperatures, Tg and Tc, respectively. The temperature Tm corresponding to a radiometer reading is given by B sub lambda(Tm) = chi-B sub lambda(Tg) + (1-chi)B sub lambda(Tc), where B sub lambda denotes the Planck blackbody function at wavelength lambda, chi specifies the fraction of the field of view occupied by the soil at a given view direction, and an emissivity of 1.0 is assumed for the plants and the soil. It is observed that at large view zenith angles, only the plants are effectively seen, and therefore Tc can be determined from the observations a large zenith angles, to the extent that such observations are practical. Water stress can produce an increase of chi and thus tends to produce an exaggerated increase in the observed temperature compared to the actual increase in canopy temperature. These effects are analyzed for a simulated soybean canopy.

  15. Direct Detection of Cylindrocarpon destructans, Root Rot Pathogen of Ginseng by Nested PCR from Soil Samples.

    PubMed

    Jang, Chang Soon; Lim, Jin Ha; Seo, Mun Won; Song, Jeong Young; Kim, Hong Gi

    2010-03-01

    We have successfully applied the nested PCR to detect Cylindrocarpon destructans, a major pathogen causing root rot disease from ginseng seedlings in our former study. The PCR assay, in this study, was used to detect the pathogen from soils. The nested PCR using internal transcribed spacer (ITS) 1, 4 primer set and Dest 1, 4 primer set maintained the specificity in soils containing various microorganisms. For a soil DNA extraction method targeting chlamydospores, when several cell wall disrupting methods were tested, the combination of lyophilization and grinding with glass beads, which broke almost all the chlamydospores, was the strongest. The DNA extraction method which was completed based on the above was simple and time-saving because of exclusion of unnecessary stages, and efficient to apply in soils. As three ginseng fields whose histories were known were analyzed, the PCR assay resulted as our expectation derived from the field information. The direct PCR method will be utilized as a reliable and rapid tool for detecting and monitoring C. destructans in ginseng fields. PMID:23956622

  16. An examination of direct and indirect effects of exposure and attention to health media on intentions to avoid unprotected sun exposure.

    PubMed

    Lovejoy, Jennette; Riffe, Daniel; Lovejoy, Travis I

    2015-01-01

    Skin cancer is the most commonly diagnosed cancer in the United States, accounting for more than 2 million diagnoses and more than 9,000 deaths annually. A regional online survey of students enrolled at institutions of higher education (N = 1,251) examined (a) associations between health media use and intentions to avoid unprotected sun exposure and (b) theoretically derived health behavior constructs that may mediate the relationship between media use and individuals' decisions to avoid unprotected sun exposure. Individuals with greater exposure and attention to health information in television, magazines, and newspapers had higher intentions to avoid unprotected sun exposure. Multiple mediation models indicated that health behavior constructs collectively mediated the relationship between television use and sun-protective behavioral intentions. Both cumulative and specific indirect mediating effects were observed for the relationship between magazine use and sun-protective behavioral intentions. However, the direction of effects was opposite to the hypothesized direction, due primarily to the association of magazine use with less favorable attitudes about sun protection and reduced behavioral control to avoid unprotected sun exposure. This study provides preliminary evidence for the interrelationships among media use, internal psychological states and cognitions, and health behavior decision making. Future studies should further explicate the mediating processes that account for the relationships between media and health behavior. PMID:24597527

  17. Effect of Rainfall-moving Direction on Slope Runoff and Soil Erosion

    NASA Astrophysics Data System (ADS)

    Wang, F.; Ran, Q.

    2014-12-01

    Although topographic characteristics is one of the factors controlling hillslope erosion, the current understanding of the impacts of rainfall-moving direction is far from thorough. In this study, a series of laboratory experiments were conducted to evaluate the effect of rainfall-moving direction and rainfall intensity on runoff generation and soil erosion.3D laser scanner were also used to monitor the slope surface changing. Runoff and sediment samples were taken at 1-min intervals. The results showed that there is one peak sediment concentration in upstream-moving rainfall events but two in downstream-moving rainfall events. Surface sealing greatly affected the sediment grading at the beginning of runoff, which results in less soil erosion. Because of the fully developed crust, the discharge peak occurred after the erosion peak in upstream-moving rainfall events, while two peaks occurred at the same time in downstream conditions. The erosion of downstream moving rainfall events were higher than upstream moving rainfall events under same condition. This study give a better understanding of hillslope erosion and crust development, which will improve the technology of water and soil conservation and numerical erosion simulation

  18. Sensitivity analysis for direct and indirect effects in the presence of exposure-induced mediator-outcome confounders

    PubMed Central

    Chiba, Yasutaka

    2014-01-01

    Questions of mediation are often of interest in reasoning about mechanisms, and methods have been developed to address these questions. However, these methods make strong assumptions about the absence of confounding. Even if exposure is randomized, there may be mediator-outcome confounding variables. Inference about direct and indirect effects is particularly challenging if these mediator-outcome confounders are affected by the exposure because in this case these effects are not identified irrespective of whether data is available on these exposure-induced mediator-outcome confounders. In this paper, we provide a sensitivity analysis technique for natural direct and indirect effects that is applicable even if there are mediator-outcome confounders affected by the exposure. We give techniques for both the difference and risk ratio scales and compare the technique to other possible approaches. PMID:25580387

  19. SOIL MICROARTHROPODS AS INDICATORS OF EXPOSURE TO ENVIRONMENTAL STRESS IN CHIHUAHUAN DESERT RANGELANDS

    EPA Science Inventory

    We studied soil microarthropod communities along livestock grazing disturbance gradients, inside and outside grazing exclosures, and on areas subjected to restoration efforts (herbicide and bulldozing) in order to test the suitability of mites as indicators of rangeland soil qual...

  20. Contingency in the Direction and Mechanics of Soil Organic Matter Responses to Increased Rainfall

    SciTech Connect

    Berhe, Asmeret A.; Suttle, K. Blake; Burton, Sarah D.; Banfield, Jillian F.

    2012-09-03

    Shifts in regional precipitation patterns will be a major component of global climate change. Rainfall will show greater and more variable changes in response to rising earth surface temperatures than most other climatic variables, and will be a major driver of ecosystem change. We studied the consequences of predicted changes in California’s rainy season for storage and stabilization mechanisms of soil organic matter (SOM). In a controlled and replicated experiment, we amended rainfall over large plots of natural grassland in accordance with alternative scenarios of future climate change. Results show that increases in annual rainfall have important consequences for soil C storage, but that the strength and even direction of these effects depend entirely on seasonal timing. Rainfall increases during the winter rainy season led to pronounced C loss from soil while rainfall increases after the typical rainy season increased soil C stocks. Analysis of mineral-OM associations reveals a powerful mechanism underlying this difference: increased winter rainfall vastly diminished the role of Fe and Al oxides in SOM stabilization. Dithionite extractable crystalline Fe oxides explained more than 35 percent of the variability in C storage in ambient control and spring-addition treatments, compared to less than 0.01 percent in the winter-addition treatment. Likewise, poorly crystalline Fe and Al oxides explained more than 25 and 40 percent of the variability in C storage, respectively, in the control and spring-addition treatments compared to less than 5 percent in the -winter-addition treatment. Increases in annual precipitation identical in amount but at three-month offsets produced opposite effects on soil C storage. These results highlight the complexity inherent in biospheric feedbacks to the climate system, and the way that careful experimentation can penetrate that complexity to improve predictions of ecosystem and climatic change.

  1. In Vitro Exposures in Diesel Exhaust Atmospheres: Resuspension of PM from Filters Verses Direct Deposition of PM from Air

    PubMed Central

    Lichtveld, Kim M.; Ebersviller, Seth M.; Sexton, Kenneth G.; Vizuete, William; Jaspers, Ilona; Jeffries, Harvey E.

    2012-01-01

    One of the most widely used in vitro particulate matter (PM) exposures methods is the collection of PM on filters, followed by resuspension in a liquid medium, with subsequent addition onto a cell culture. To avoid disruption of equilibria between gases and PM, we have developed a direct in vitro sampling and exposure method (DSEM) capable of PM-only exposures. We hypothesize that the separation of phases and post-treatment of filter-collected PM significantly modifies the toxicity of the PM compared to direct deposition, resulting in a distorted view of the potential PM health effects. Controlled test environments were created in a chamber that combined diesel exhaust with an urban-like mixture. The complex mixture was analyzed using both the DSEM and concurrently-collected filter samples. The DSEM showed that PM from test atmospheres produced significant inflammatory response, while the resuspension exposures at the same exposure concentration did not. Increasing the concentration of resuspended PM sixteen times was required to yield measurable IL-8 expression. Chemical analysis of the resuspended PM indicated a total absence of carbonyl compounds compared to the test atmosphere during the direct-exposures. Therefore, collection and resuspension of PM into liquid modifies its toxicity and likely leads to underestimating toxicity. PMID:22834915

  2. Responses of soil ammonia-oxidizing microorganisms to repeated exposure of single-walled and multi-walled carbon nanotubes.

    PubMed

    Chen, Qinglin; Wang, Hui; Yang, Baoshan; He, Fei; Han, Xuemei; Song, Ziheng

    2015-02-01

    The impacts of carbon nanotubes (CNTs) including single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) on soil microbial biomass and microbial community composition (especially on ammonium oxidizing microorganisms) have been evaluated. The first exposure of CNTs lowered the microbial biomass immediately, but the values recovered to the level of the control at the end of the experiment despite the repeated addition of CNTs. The abundance and diversity of ammonium-oxidizing archaea (AOA) were higher than that of ammonium-oxidizing bacteria (AOB) under the exposure of CNTs. The addition of CNTs decreased Shannon-Wiener diversity index of AOB and AOA. Two-way ANOVA analysis showed that CNTs had significant effects on the abundance and diversity of AOB and AOA. Dominant terminal restriction fragments (TRFs) of AOB exhibited a positive relationship with NH4(+), while AOA was on the contrary. It implied that AOB prefer for high-NH4(+) soils whereas AOA is favored in low NH4(+) soils in the CNT-contaminated soil. PMID:25461068

  3. Garden soil and house dust as exposure media for lead uptake in the mining village of Stratoni, Greece.

    PubMed

    Argyraki, Ariadne

    2014-08-01

    The relationships between two exposure media, garden soil and house dust, were studied for Pb uptake in Stratoni village in northern Greece, an industrial area of mining and processing of sulphide ore. Lead data for the two media were assessed in terms of total and bioaccessible content, measurement and geochemical variability, and mineralogical composition. It was found that total Pb was enriched in house dust samples by a factor of 2 on average. Total Pb concentration in soil samples had a maximum of 2,040 mg/kg and reached a maximum of 7,000 mg/kg in house dust samples. The estimated variability due to measurement uncertainty was dominated by the sampling process, and the proportion of sampling variance was greater for soil samples, indicating a higher degree of Pb heterogeneity in soil on the given spatial scale of sampling strata. Although the same general spatial trend was observed for both sampling media with decreasing Pb concentration by increasing distance from the ore-processing plant, Pb in dust samples displayed the highest concentrations within a 300-600-m zone from the ore-processing facility. The significant differences which were observed in Pb speciation between the studied media were explained by differences in mineralogical composition of outdoor soil and indoor dust. Lead-enriched Fe and Mn oxides predominated in soil samples while fine galena grains (<10-20 μm diameter) were the major Pb-bearing phase in dust samples. The integrated exposure uptake biokinetic model was used to predict the risk of elevated blood lead levels in children of Stratoni. Model prediction indicated an average probability of 61 % for blood-Pb to exceed 10 μg/dl. The results underline the importance of house dust in risk assessment and highlight the effect of outdoor and indoor conditions on the fate of Pb in the particular environment of Stratoni. PMID:24292695

  4. Anaerobic soil disinfestation for soil borne disease control in strawberry and vegetable systems: Current knowledge and future directions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD), a biological alternative to soil fumigation, has been shown to control a wide range of soil-borne pathogens and nematodes in numerous crop production systems across Japan, the Netherlands and the U.S. A brief review of the status of the science behind ASD and its...

  5. TEM Analyses of Itokawa Regolith Grains and Lunar Soil Grains to Directly Determine Space Weathering Rates on Airless Bodies

    NASA Technical Reports Server (NTRS)

    Berger, Eve L.; Keller, Lindsay P.; Christoffersen, Roy

    2016-01-01

    Samples returned from the moon and Asteroid Itokawa by NASA's Apollo Missions and JAXA's Hayabusa Mission, respectively, provide a unique record of their interaction with the space environment. Space weathering effects result from micrometeorite impact activity and interactions with the solar wind. While the effects of solar wind interactions, ion implantation and solar flare particle track accumulation, have been studied extensively, the rate at which these effects accumulate in samples on airless bodies has not been conclusively determined. Results of numerical modeling and experimental simulations do not converge with observations from natural samples. We measured track densities and rim thicknesses of three olivine grains from Itokawa and multiple olivine and anorthite grains from lunar soils of varying exposure ages. Samples were prepared for analysis using a Leica EM UC6 ultramicrotome and an FEI Quanta 3D dual beam focused ion beam scanning electron microscope (FIB-SEM). Transmission electron microscope (TEM) analyses were performed on the JEOL 2500SE 200kV field emission STEM. The solar wind damaged rims on lunar anorthite grains are amorphous, lack inclusions, and are compositionally similar to the host grain. The rim width increases as a smooth function of exposure age until it levels off at approximately 180 nm after approximately 20 My (Fig. 1). While solar wind ion damage can only accumulate while the grain is in a direct line of sight to the Sun, solar flare particles can penetrate to mm-depths. To assess whether the track density accurately predicts surface exposure, we measured the rim width and track density in olivine and anorthite from the surface of rock 64455, which was never buried and has a surface exposure age of 2 My based on isotopic measurements. The rim width from 64455 (60-70nm) plots within error of the well-defined trend for solar wind amorphized rims in Fig. 1. Measured solar flare track densities are accurately reflecting the

  6. Rapid monitoring of soil, smears, and air dusts by direct large-area alpha spectrometry

    SciTech Connect

    Sill, C.W.

    1992-01-01

    Experimental conditions to permit rapid monitoring of soils, smears, and air dusts for transuranic (TRU) radionuclides under field conditions are described. The monitoring technique involves direct measurement of alpha emitters by alpha spectrometry using a large-area detector to identify and quantify the radionuclides present. The direct alpha spectrometry employs a circular gridded ionization chamber 35 cm in diameter which accommodates either a circular sample holder 25 cm in diameter or a rectangular one 20 by 25 cm (8 by 10 in.). Soils or settled dusts are finely ground, suspended in 30% ethanol, and sprayed onto a 25-cm stainless steel dish. Air dusts are collected with a high-volume sampler onto 20- by 25-cm membrane filters. Removable contamination is collected from surfaces onto a 20- by 25-cm filter using an 18-cm (7-in.) paint roller to hold the large filter in contact with the surface during sample collection. All three types of samples are then counted directly in the alpha spectrometer and no other sample preparation is necessary. Some results obtained are described.

  7. Sterilization/disinfection using reduced-pressure plasmas: some differences between direct exposure of bacterial spores to a discharge and their exposure to a flowing afterglow

    NASA Astrophysics Data System (ADS)

    Moisan, M.; Levif, P.; Séguin, J.; Barbeau, J.

    2014-07-01

    The use of plasma for sterilization or disinfection offers a promising alternative to conventional steam or chemical approaches. Plasma can operate at temperatures less damaging to some heat-sensitive medical devices and, in contrast to chemicals, can be non-toxic and non-polluting for the operator and the environment, respectively. Direct exposure to the gaseous discharge (comprising an electric field and ions/electrons) or exposure to its afterglow (no E-field) can both be envisaged a priori, since these two methods can achieve sterility. However, important issues must be considered besides the sterility goal. Direct exposure to the discharge, although yielding a faster inactivation of microorganisms, is shown to be potentially more aggressive to materials and sometimes subjected to the shadowing effect that precludes the sterilization of complex-form items. These two drawbacks can be successfully minimized with an adequate flowing-afterglow exposure. Most importantly, the current paper shows that direct exposure to the discharge can lead to the dislodgment and release of viable microorganisms from their substratum. Such a phenomenon could be responsible for the recontamination of sterilized devices as well as possible contamination of the ambient surroundings, additionally yielding an erroneous over-appreciation of the inactivation efficiency. The operation of the N2-O2 flowing afterglow system being developed in our group is such that there are no ions and electrons left in the process chamber (late-afterglow regime) in full contrast with their presence in the discharge. The dislodgment and release of spores could be attributed, based on the literature, to their electrostatic charging by electrons, leading to an (outward) electrostatic stress that exceeds the adhesion of the spores on their substrate.

  8. Direct Determination of the Space Weathering Rates in Lunar Soils and Itokawa Regolith from Sample Analyses

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Berger, E. L.; Christoffersen, R.; Zhang, S.

    2016-01-01

    Space weathering effects on airless bodies result largely from micrometeorite impacts and solar wind interactions. Decades of research have provided insights into space weathering processes and their effects, but a major unanswered question still remains: what is the rate at which these space weathering effects are acquired in lunar and asteroidal regolith materials? To determine the space weathering rate for the formation of rims on lunar anorthite grains, we combine the rim width and type with the exposure ages of the grains, as determined by the accumulation of solar flare particle tracks. From these analyses, we recently showed that space weathering effects in mature lunar soils (both vapor-deposited rims and solar wind amorphized rims) accumulate and attain steady state in 10(sup 6)-10(sup 7) y. Regolith grains from Itokawa also show evidence for space weathering effects, but in these samples, solar wind interactions appear to dominate over impactrelated effects such as vapor-deposition. While in our lunar work, we focused on anorthite, given its high abundance on the lunar surface, for the Itokawa grains, we focused on olivine. We previously studied 3 olivine grains from Itokawa and determined their solar flare track densities and described their solar wind damaged rims]. We also analyzed olivine grains from lunar soils, measured their track densities and rim widths, and used this data along with the Itokawa results to constrain the space weathering rate on Itokawa. We observe that olivine and anorthite have different responses to solar wind irradiation.

  9. Use of direct versus indirect preparation data for assessing risk associated with airborne exposures at asbestos-contaminated sites.

    PubMed

    Goldade, Mary Patricia; O'Brien, Wendy Pott

    2014-01-01

    At asbestos-contaminated sites, exposure assessment requires measurement of airborne asbestos concentrations; however, the choice of preparation steps employed in the analysis has been debated vigorously among members of the asbestos exposure and risk assessment communities for many years. This study finds that the choice of preparation technique used in estimating airborne amphibole asbestos exposures for risk assessment is generally not a significant source of uncertainty. Conventionally, the indirect preparation method has been less preferred by some because it is purported to result in false elevations in airborne asbestos concentrations, when compared to direct analysis of air filters. However, airborne asbestos sampling in non-occupational settings is challenging because non-asbestos particles can interfere with the asbestos measurements, sometimes necessitating analysis via indirect preparation. To evaluate whether exposure concentrations derived from direct versus indirect preparation techniques differed significantly, paired measurements of airborne Libby-type amphibole, prepared using both techniques, were compared. For the evaluation, 31 paired direct and indirect preparations originating from the same air filters were analyzed for Libby-type amphibole using transmission electron microscopy. On average, the total Libby-type amphibole airborne exposure concentration was 3.3 times higher for indirect preparation analysis than for its paired direct preparation analysis (standard deviation = 4.1), a difference which is not statistically significant (p = 0.12, two-tailed, Wilcoxon signed rank test). The results suggest that the magnitude of the difference may be larger for shorter particles. Overall, neither preparation technique (direct or indirect) preferentially generates more precise and unbiased data for airborne Libby-type amphibole concentration estimates. The indirect preparation method is reasonable for estimating Libby-type amphibole exposure and

  10. Direct observation of local xylem embolisms induced by soil drying in intact Zea mays leaves.

    PubMed

    Ryu, Jeongeun; Hwang, Bae Geun; Kim, Yangmin X; Lee, Sang Joon

    2016-04-01

    The vulnerability of vascular plants to xylem embolism is closely related to their stable long-distance water transport, growth, and survival. Direct measurements of xylem embolism are required to understand what causes embolism and what strategies plants employ against it. In this study, synchrotron X-ray microscopy was used to non-destructively investigate both the anatomical structures of xylem vessels and embolism occurrence in the leaves of intact Zea mays (maize) plants. Xylem embolism was induced by water stress at various soil drying periods and soil water contents. X-ray images of dehydrated maize leaves showed that the ratio of gas-filled vessels to all xylem vessels increased with decreased soil water content and reached approximately 30% under severe water stress. Embolism occurred in some but not all vessels. Embolism in maize leaves was not strongly correlated with xylem diameter but was more likely to occur in the peripheral veins. The rate of embolism formation in metaxylem vessels was higher than in protoxylem vessels. This work has demonstrated that xylem embolism remains low in maize leaves under water stress and that there xylem has characteristic spatial traits of vulnerability to embolism. PMID:26946123

  11. Direct observation of local xylem embolisms induced by soil drying in intact Zea mays leaves

    PubMed Central

    Ryu, Jeongeun; Hwang, Bae Geun; Kim, Yangmin X.; Lee, Sang Joon

    2016-01-01

    The vulnerability of vascular plants to xylem embolism is closely related to their stable long-distance water transport, growth, and survival. Direct measurements of xylem embolism are required to understand what causes embolism and what strategies plants employ against it. In this study, synchrotron X-ray microscopy was used to non-destructively investigate both the anatomical structures of xylem vessels and embolism occurrence in the leaves of intact Zea mays (maize) plants. Xylem embolism was induced by water stress at various soil drying periods and soil water contents. X-ray images of dehydrated maize leaves showed that the ratio of gas-filled vessels to all xylem vessels increased with decreased soil water content and reached approximately 30% under severe water stress. Embolism occurred in some but not all vessels. Embolism in maize leaves was not strongly correlated with xylem diameter but was more likely to occur in the peripheral veins. The rate of embolism formation in metaxylem vessels was higher than in protoxylem vessels. This work has demonstrated that xylem embolism remains low in maize leaves under water stress and that there xylem has characteristic spatial traits of vulnerability to embolism. PMID:26946123

  12. COMPARISON AND EVALUATION OF FIELD METHODS (DIRECT AND INDIRECT) TO ESTIMATE SOIL WATER FLUXES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of soil water fluxes is critical for evaluating efficiency and environmental effects of soil and crop management. Indirect methods commonly used to estimate soil water fluxes estimates are currently based on (a) soil water balance, (b) soil water potential measurements with the Darcy-Bucki...

  13. Direct and indirect measurement of patient radiation exposure during endovascular aortic aneurysm repair.

    PubMed

    Weiss, Dustin J; Pipinos, Iraklis I; Longo, G Mathew; Lynch, Thomas G; Rutar, Frank J; Johanning, Jason M

    2008-11-01

    With the increasing complexity of endovascular procedures, concern has grown regarding patient radiation exposure. Abdominal aortic aneurysm (AAA) repair represents the most common complex endovascular procedure currently performed by vascular specialists. Our study evaluates the patient radiation dose received during endovascular AAA repair. Over a 3-month period we prospectively monitored the radiation dose in a series of consecutive patients undergoing endovascular AAA repair. All patients underwent standard endovascular AAA repair with one of two commercially available grafts using the GE OEC 9800 unit. Direct measurement of maximum radiation dose at skin level (peak skin dose, PSD) was recorded using GAFCHROMIC radiographic dosimetry film. Indirect measurements of radiation dose (fluoroscopy time and dose-area-product [DAP]) were recorded with the C-arm dosimeter. A total of 12 consecutive patients undergoing standard endovascular AAA repair were evaluated. Mean PSD was 0.75 Gy (range 0.27-1.25). Mean total fluoroscopy time was 20.6 min (range 12.6-34.2) with an average of 92% spent in standard fluoroscopy and 8% spent in cinefluoroscopy. Regarding total fluoroscopy time, 49% was spent in normal field of view and 51% in magnified view. Mean DAP was 15,166 cGy x cm(2) (range 5,207-24,536). PSD correlated with DAP (r = 0.9, p < 0.05) but not total fluoroscopy time (r = 0.18, p > 0.05). PSD also correlated with body mass index (BMI; r = 0.82, p < 0.05). Obese patients had a mean PSD of 1.1 Gy compared to 0.5 Gy in nonobese patients. PSD of all patients was well below the accepted 2.0 Gy threshold for skin injury. PSD correlated with DAP but not total fluoroscopy time. PSD also correlated with BMI, and the mean PSD was significantly increased in obese compared to nonobese patients. Despite the complexity and duration of endovascular AAA repair, the procedure can be performed safely without excessive radiation exposure. PMID:18992664

  14. INTERNAL GRANT: DEVELOPMENT OF SOURCE APPORTIONMENT/EXPOSURE ESTIMATION METHODS WITH WIND DIRECTION (A DIRECTIONAL ANALYSIS ASSESSMENT)

    EPA Science Inventory

    Purpose of research is to use PM2.5, PM10, and gaseous species with meteorology to assess source emission impacts and transboundary air pollution in the U.S.-Mexico border region; this is being done by performing directional analysis techniques based on wind direction analysis an...

  15. Accelerated Biodegradation of Veterinary Antibiotics in Agricultural Soil following Long-Term Exposure, and Isolation of a Sulfamethazine-degrading sp.

    PubMed

    Topp, Edward; Chapman, Ralph; Devers-Lamrani, Marion; Hartmann, Alain; Marti, Romain; Martin-Laurent, Fabrice; Sabourin, Lyne; Scott, Andrew; Sumarah, Mark

    2013-01-01

    The World Health Organization has identified antibiotic resistance as one of the top three threats to global health. There is concern that the use of antibiotics as growth promoting agents in livestock production contributes to the increasingly problematic development of antibiotic resistance. Many antibiotics are excreted at high rates, and the land application of animal manures represents a significant source of environmental exposure to these agents. To evaluate the long-term effects of antibiotic exposure on soil microbial populations, a series of field plots were established in 1999 that have since received annual applications of a mixture of sulfamethazine (SMZ), tylosin (TYL), and chlortetracycline (CTC). During the first 6 yr (1999-2004) soils were treated at concentrations of 0, 0.01 0.1, and 1.0 mg kg soil, in subsequent years at concentrations of 0, 0.1, 1.0, and 10 mg kg soil. The lower end of this concentration range is within that which would result from an annual application of manure from medicated swine. Following ten annual applications, the fate of the drugs in the soil was evaluated. Residues of SMZ and TYL, but not CTC were removed much more rapidly in soil with a history of exposure to 10 mg/kg drugs than in untreated control soil. Residues of C-SMZ were rapidly and thoroughly mineralized to CO in the historically treated soils, but not in the untreated soil. A SMZ-degrading sp. was isolated from the treated soil. Overall, these results indicate that soil bacteria adapt to long-term exposure to some veterinary antibiotics resulting in sharply reduced persistence. Accelerated biodegradation of antibiotics in matrices exposed to agricultural, wastewater, or pharmaceutical manufacturing effluents would attenuate environmental exposure to antibiotics, and merits investigation in the context of assessing potential risks of antibiotic resistance development in environmental matrices. PMID:23673752

  16. Cadmium exposure via diet and its implication on the derivation of health-based soil screening values in China.

    PubMed

    Zhong, Mao-Sheng; Jiang, Lin; Han, Dan; Xia, Tian-Xiang; Yao, Jue-Jun; Jia, Xiao-Yang; Peng, Chao

    2015-01-01

    The cadmium (Cd) intake rates via diet of adults from different regions in China were between 0.160 and 0.557 μg/(kg BW·day), which were less than the provisional tolerable monthly intake (0.833 μg/(kg BW·day)) issued by Food and Agriculture Organization/World Health Organization in 2010, but higher than the one (0.365 μg/(kg BW·day)) issued by the European Food Safety Authority in 2011, to protect children, vegetarians and people living in heavily contaminated regions, and the intake rate of children (1.007 μg/(kg BW·day)) at the national scale was higher than the values recommended by the above institutes and those of adults. Vegetables were the critical contributors, followed by rice, flour, meats and aquatic products. Cd concentration in vegetable was the most sensitive factor in calculating the intake rate, followed by its contents in rice and aquatic products, and the intake rate of flour, indicating that more attention should be given to these parameters in future total diet surveys. When dietary exposure was incorporated, the derived national screening value of Cd under commercial scenario was reduced from 825 to 458 mg/kg, while the values of the north, south, Beijing and Shanghai were reduced to 627, 365, 693 and 489 mg/kg, respectively, indicating that the hazard would be underestimated if dietary exposure was not taken into account, especially for the south. The great variance between the screening values was due to the varied Cd intake rates, which indicated that deriving a screening value for each specific area based on its corresponding exposure characteristics was more appropriate. The national screening level for the residential scenario derived theoretically based on the dietary exposure characteristics of children was a negative value, meaning that the dietary intake rate was above the tolerable value. The method used in the United Kingdom to derive soil guideline values when non-soil exposure accounted for more than half of

  17. A novel mouse model for the study of the inhibitory effects of chronic ethanol exposure on direct bone formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive alcohol consumption has been reported to interfere with human bone homeostasis and repair in multiple ways. Previous studies have demonstrated that chronic ethanol exposure in the rat via an intragastric dietary delivery system inhibits direct bone formation during distraction osteogenesis...

  18. Advances and Future Directions in the Study of Children's Neurobiological Responses to Trauma and Violence Exposure

    ERIC Educational Resources Information Center

    Bevans, Katherine; Cerbone, Arleen B.; Overstreet, Stacy

    2005-01-01

    One of the most exciting developments to emerge from the field in the past 20 years is the increasing attention to neurobiological responses to violence and trauma exposure. Although researchers have yet to identify a consensual pattern of neurobiological response to violence and trauma exposure, it does appear that some type of alteration in the…

  19. Waterpipe Tobacco Smoking and Cigarette Smoking: A Direct Comparison of Toxicant Exposure and Subjective Effects

    PubMed Central

    Cobb, Caroline O.; Shihadeh, Alan; Weaver, Michael F.

    2011-01-01

    Introduction: Waterpipe tobacco smoking is increasing worldwide and is believed by many users to be less harmful and addictive than cigarette smoking. In fact, waterpipe tobacco and cigarette smoke contain many of the same chemicals, and users are exposed to the dependence-producing drug nicotine as well as other smoke toxicants. The subjective effect profile of these 2 tobacco use methods has not been compared directly, though this information is relevant to understanding the risk of dependence development. Methods: Fifty-four participants who reported waterpipe and cigarette smoking completed 2, 45-min, counter-balanced sessions in which they completed a waterpipe use episode (mean smoking time = 43.3 min) or a cigarette (mean = 6.1 min). Outcome measures included plasma nicotine, carboxyhemoglobin (COHb), and subjective effects, including those relevant to predicting dependence potential. Results: Mean (±SEM) peak plasma nicotine concentration did not differ by session (waterpipe = 9.8 ± 1.0 ng/ml; cigarette = 9.4 ± 1.0 ng/ml). Mean peak COHb concentration differed significantly (waterpipe = 4.5% ± 0.3%; cigarette = 1.2% ± 0.1%). Subjective effect changes for waterpipe and cigarette were comparable in magnitude but often longer lived for waterpipe. Conclusions: Relative to a cigarette, waterpipe tobacco smoking was associated with similar peak nicotine exposure, 3.75-fold greater COHb, and 56-fold greater inhaled smoke volume. Waterpipe and cigarette influenced many of the same subjective effect measures. These findings are consistent with the conclusion that waterpipe tobacco smoking presents substantial risk of dependence, disease, and death, and they can be incorporated into prevention interventions that might help deter more adolescents and young adults from experimenting with an almost certainly lethal method of tobacco use. PMID:21127030

  20. Direct detection of recombinant gene expression by two genetically engineered yeasts in soil on the transcriptional and translational levels.

    PubMed Central

    Tebbe, C C; Wenderoth, D F; Vahjen, W; Lübke, K; Munch, J C

    1995-01-01

    The expression of a recombinant gene by yeasts seeded into soil samples was directly measured by analyzing transcripts and gene product occurrences in soil extracts. Two yeast species, Saccharomyces cerevisiae WHL292 and Hansenula polymorpha LR9-Apr4, both engineered by a synthetic gene sequence encoding the mammalian peptide aprotinin, produced and secreted this peptide in batch cultures at concentrations of 90 and 64 ng ml-1, respectively. In S. cerevisiae, the aprotinin gene was located on plasmid p707 and expressed constitutively. H. polymorpha carried the gene chromosomally integrated, and its expression was inducible by methanol. To detect aprotinin transcripts, cells were directly lysed in the soil samples and the crude lysates were hybridized to oligo(dT)-coated magnetized polystyrene beads (Dynabeads). After separation and purification in a magnetic field, aprotinin mRNA was detected by reverse transcriptase PCR with aprotinin gene-specific primers. Transcripts from 10 cells g of soil-1 were sufficient for detection. When 10(7) cells of S. cerevisiae were inoculated into soil, aprotinin mRNA was detectable during the first 4 days. Addition of methanol and a combined nutrient solution was necessary to induce aprotinin gene expression of H. polymorpha in soil. Aprotinin could be detected directly in soil extracts by an indirect enzyme-linked immunosorbent assay with monoclonal aprotinin-specific antibodies. The detection threshold was 45 pg g of soil-1. In presterilized soil inoculated with S. cerevisiae (10(6) CFU g-1), aprotinin accumulated during the first 10 days to 12 ng g of soil-1 and then remained constant.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8534097

  1. Risk analysis of PCB exposure via the soil-food crop pathway, and alternatives for remediation at Serpukhov, Russian Federation

    SciTech Connect

    Tsongas, T.; Orlinskii, D.; Priputina, I.; Pleskachevskaya, G.; Fetishchev, A.; Hinman, G.; Butcher, W.

    2000-02-01

    A risk assessment was conducted to determine the likelihood of certain health risks resulting from exposure to soils and food crops contaminated with polychlorinated biphenyl (PCBs). PCBs have contaminated soils, river sediments, and air in the past as a result of industrial activities at a capacitor plant located in the City of Serpukhov, Russian Federation. This risk assessment and suggestions for remediation are designed to aid in decision-making efforts by a joint Russian-American research team developing a community, national, and international response to industrial contamination. Bobovnikova et al. have reported that PCBs are elevated in soils and sediments, breast milk, and locally grown foods in the Serpukhov area. Data from these and other investigators have been used in this risk assessment to calculate a potential cancer risk resulting from exposure to PCBs. Their assessment indicates that members of the local population may be at increased risk of cancer, and possibly other adverse health effects, as a result of PCB contamination of their environment. Because previously unassessed environmental contamination is a common problem in the former Soviet Republics, as well as many other areas of the world, the authors believe this type of evaluation, using known methods, can serve as a model for assessment efforts in other parts of the globe and result in remediative efforts in regions constrained by faltering economies.

  2. A structural equation model of soil metal bioavailability to earthworms: confronting causal theory and observations using a laboratory exposure to field-contaminated soils.

    PubMed

    Beaumelle, Léa; Vile, Denis; Lamy, Isabelle; Vandenbulcke, Franck; Gimbert, Frédéric; Hedde, Mickaël

    2016-11-01

    Structural equation models (SEM) are increasingly used in ecology as multivariate analysis that can represent theoretical variables and address complex sets of hypotheses. Here we demonstrate the interest of SEM in ecotoxicology, more precisely to test the three-step concept of metal bioavailability to earthworms. The SEM modeled the three-step causal chain between environmental availability, environmental bioavailability and toxicological bioavailability. In the model, each step is an unmeasured (latent) variable reflected by several observed variables. In an exposure experiment designed specifically to test this SEM for Cd, Pb and Zn, Aporrectodea caliginosa was exposed to 31 agricultural field-contaminated soils. Chemical and biological measurements used included CaC12-extractable metal concentrations in soils, free ion concentration in soil solution as predicted by a geochemical model, dissolved metal concentration as predicted by a semi-mechanistic model, internal metal concentrations in total earthworms and in subcellular fractions, and several biomarkers. The observations verified the causal definition of Cd and Pb bioavailability in the SEM, but not for Zn. Several indicators consistently reflected the hypothetical causal definition and could thus be pertinent measurements of Cd and Pb bioavailability to earthworm in field-contaminated soils. SEM highlights that the metals present in the soil solution and easily extractable are not the main source of available metals for earthworms. This study further highlights SEM as a powerful tool that can handle natural ecosystem complexity, thus participating to the paradigm change in ecotoxicology from a bottom-up to a top-down approach. PMID:27378153

  3. Study of the Effect of Specimen Shape in Direct Tension Tests on Cohesive Soil

    NASA Astrophysics Data System (ADS)

    Nishimura, Shin-Ichi

    It is important to evaluate characteristics of tensile strength of foundation and embankment material of fill-dam for the examination of the development conditions of crack which is one of the causes for hydraulic fracturing. Though it is possible to evaluate the tensile strength of hard rock by fixing both ends of the specimen with chucks and making it work directly, it is not possible to use the same method for soft material like cohesive soil. Hence direct tensile test was performed in this research to measure the tensile strength by changing the column type specimen for the compression test into an I-shaped specimen and using the devices that were experimentally-made for the test. Moreover, the stress generated in the specimen was calculated by the FEM analysis and the form of the specimen for the direct tensile test was suggested. It gave useful result for the direct tensile test, with the specimen being further thinned only in the center part of the I-shaped specimen.

  4. Effects of soil water content on the external exposure of fauna to radioactive isotopes.

    PubMed

    Beaugelin-Seiller, K

    2016-01-01

    Within a recent model intercomparison about radiological risk assessment for contaminated wetlands, the influence of soil saturation conditions on external dose rates was evidenced. This issue joined concerns of assessors regarding the choice of the soil moisture value to input in radiological assessment tools such as the ERICA Tool. Does it really influence the assessment results and how? This question was investigated under IAEA's Modelling and Data for Radiological Impacts Assessments (MODARIA) programme via 42 scenarios for which the soil water content varied from 0 (dry soil) to 100% (saturated soil), in combination with other parameters that may influence the values of the external dose conversion coefficients (DCCs) calculated for terrestrial organisms exposed in soil. A set of α, β, and γ emitters was selected in order to cover the range of possible emission energies. The values of their external DCCs varied generally within a factor 1 to 1.5 with the soil water content, excepted for β emitters that appeared more sensitive (DCCs within a factor of about 3). This may be of importance for some specific cases or for upper tiers of radiological assessments, when refinement is required. But for the general purpose of screening assessment of radiological impact on fauna and flora, current approaches regarding the soil water content are relevant. PMID:26492396

  5. Uncertainty and variability in human exposures to soil contaminants through home-grown food: A Monte Carlo assessment

    SciTech Connect

    McKone, T.E.

    1994-08-01

    This paper presents a general model for exposure to homegrown foods that is used with a Monte Carlo analysis to determine the relative contributions of variability (Type A uncertainty) and true uncertainty (Type B uncertainty) to the overall variance in prediction of the dose-to-concentration ratio. Although classification of exposure inputs as uncertain or variable is somewhat subjective, food consumption rates and exposure duration are judged to have a predicted variance that is dominated by variability among individuals by age, income, culture, and geographical region. Whereas, biotransfer factors and partition factors are inputs that, to a large extent, involve uncertainty. Using ingestion of fruits, vegetables, grains dairy products, and meat and soils assumed to be contaminated by hexachlorbenzene (HCB) and benzo(a)pyrene (BaP) as case studies, a Monte Carlo analysis is used to explore the relative contribution of uncertainty and variability to overall variance in the estimated distribution of potential dose within the population that consumes homegrown foods. It is found that, when soil concentrations are specified, variances in ratios of dose-to-concentration for HCB are equally attributable to uncertainty and variability, whereas for BaP, variance in these ratios is dominated by true uncertainty. 44 refs., 4 figs. 4 tabs.

  6. Environmental Variables Shaping the Ecological Niche of Thaumarchaeota in Soil: Direct and Indirect Causal Effects

    PubMed Central

    Hong, Jin-Kyung; Cho, Jae-Chang

    2015-01-01

    To find environmental variables (EVs) shaping the ecological niche of the archaeal phylum Thaumarchaeota in terrestrial environments, we determined the abundance of Thaumarchaeota in various soil samples using real-time PCR targeting thaumarchaeotal 16S rRNA gene sequences. We employed our previously developed primer, THAUM-494, which had greater coverage for Thaumarchaeota and lower tolerance to nonthaumarchaeotal taxa than previous Thaumarchaeota-directed primers. The relative abundance estimates (RVs) of Thaumarchaeota (RTHAUM), Archaea (RARCH), and Bacteria (RBACT) were subjected to a series of statistical analyses. Redundancy analysis (RDA) showed a significant (p < 0.05) canonical relationship between RVs and EVs. Negative causal relationships between RTHAUM and nutrient level–related EVs were observed in an RDA biplot. These negative relationships were further confirmed by correlation and regression analyses. Total nitrogen content (TN) appeared to be the EV that affected RTHAUM most strongly, and total carbon content (TC), which reflected the content of organic matter (OM), appeared to be the EV that affected it least. However, in the path analysis, a path model indicated that TN might be a mediator EV that could be controlled directly by the OM. Additionally, another path model implied that water content (WC) might also indirectly affect RTHAUM by controlling ammonium nitrogen (NH4+-N) level through ammonification. Thus, although most directly affected by NH4+-N, RTHAUM could be ultimately determined by OM content, suggesting that Thaumarchaeota could prefer low-OM or low-WC conditions, because either of these EVs could subsequently result in low levels of NH4+-N in soil. PMID:26241328

  7. French children's exposure to metals via ingestion of indoor dust, outdoor playground dust and soil: contamination data.

    PubMed

    Glorennec, Philippe; Lucas, Jean-Paul; Mandin, Corinne; Le Bot, Barbara

    2012-09-15

    In addition to dietary exposure, children are exposed to metals via ingestion of soils and indoor dust, contaminated by natural or anthropogenic outdoor and indoor sources. The objective of this nationwide study was to assess metal contamination of soils and dust which young French children are exposed to. A sample of 484 children (6 months to 6 years) was constituted in order to obtain representative results for young French children. In each home indoor settled dust was sampled by a wipe in up to five rooms. Outdoor playgrounds were sampled with a soil sample ring (n=315) or with a wipe in case of hard surfaces (n=53). As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V were measured because of their potential health concern due to soil and dust ingestion. The samples were digested with hydrochloric acid, and afterwards aqua regia in order to determine both leachable and total metal concentrations and loadings by mass spectrometry with a quadrupole ICP-MS. In indoor settled dust most (total) loadings were below the Limit of Quantification (LOQ), except for Pb and Sr, whose median loadings were respectively 9 and 10 μg/m². The 95th percentile of loadings were 2 μg/m² for As, <0.8 for Cd, 18 for Cr, 49 for Cu, <64 for Mn, 63 for Pb, 2 for Sb, 56 for Sr, and <8 for V. Median/95th percentile of loadings in settled dust on outdoor playgrounds were 2/16, <0.8/1.3, 17/53, 49/330, 99/424, 32/393, 2/13, 86/661 and 10/37 μg/m² for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. In outdoor playground soil median/95th percentile of concentrations (μg/g) were 8/26, <0.65/1, 25/52, <26/53,391/956, 27/254, 0.7/4, 54/295, 23/57 for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. These results are comparable with those observed in other countries. Because of their representative nature, we can assess children's exposures to these metals via soil and dust and the associated risks in urban and rural environments. Ratios of leachable/total concentrations and loadings, calculated on

  8. Exposure to particulate matter in India: A synthesis of findings and future directions.

    PubMed

    Pant, Pallavi; Guttikunda, Sarath K; Peltier, Richard E

    2016-05-01

    Air pollution poses a critical threat to human health with ambient and household air pollution identified as key health risks in India. While there are many studies investigating concentration, composition, and health effects of air pollution, investigators are only beginning to focus on estimating or measuring personal exposure. Further, the relevance of exposures studies from the developed countries in developing countries is uncertain. This review summarizes existing research on exposure to particulate matter (PM) in India, identifies gaps and offers recommendations for future research. There are a limited number of studies focused on exposure to PM and/or associated health effects in India, but it is evident that levels of exposure are much higher than those reported in developed countries. Most studies have focused on coarse aerosols, with a few studies on fine aerosols. Additionally, most studies have focused on a handful of cities, and there are many unknowns in terms of ambient levels of PM as well as personal exposure. Given the high mortality burden associated with air pollution exposure in India, a deeper understanding of ambient pollutant levels as well as source strengths is crucial, both in urban and rural areas. Further, the attention needs to expand beyond the handful large cities that have been studied in detail. PMID:26974362

  9. Enrichment and exposure assessment of As, Cr and Pb of the soils in the vicinity of Stawell, Victoria, Australia.

    PubMed

    Noble, Ryan R P; Hough, Robert M; Watkins, Ronald T

    2010-06-01

    Stawell Gold Mine in NW Victoria, Australia, mines ores that contain large concentrations of As and significant quantities of the metals Pb and Cr. The aim of this research was to understand the dispersion, enrichment and probable exposure of these potentially hazardous elements around the mine site. Fifty-five surface soil samples were collected near the mine (<15 km) and analysed by ICP-MS/OES following bioavailable and four-acid extractions. Soils near the mine show greater concentrations of As, Cr and Pb than those near a regionally determined background. This is attributed to the combination of a natural geochemical halo around mineralization and anthropogenic dispersion due to mining and urbanization. Total As concentrations were between 16 and 946 mg kg(-1) near the mine in a regional background of 1-16 mg kg(-1). Total Cr concentrations were between 18 and 740 mg kg(-1) near the mine in a regional background of 26-143 mg kg(-1). Total Pb concentrations were between 12 and 430 mg kg(-1) near the mine in a regional background of 9-23 mg kg(-1). Dispersion of contaminant elements from the present ore processing is <500 m. The most enriched soils occur close to the town and are unrelated to present mining practices. The bioavailable As, Cr and Pb, soil ingestion rates and Risk Reference Doses were used to estimate health risks. An average toddler (12 kg) would need to consume at least 1.5 g, and most likely 12 g, of soil per day to show some symptoms of As toxicity. The maximum measured bioavailable As would pose a risk at average ingestion rates of 200 mg per day. Individuals with soil-eating disorders would exceed the safe daily consumption limits for As, and potentially Cr and Pb. Small children are not typically exposed to soil everyday, very few have soil eating disorders, and, therefore, the health risk from the soils around the mine is minimal. PMID:19779837

  10. Moving toward exposure and risk evaluation of nanomaterials: challenges and future directions.

    PubMed

    Thomas, Treye; Bahadori, Tina; Savage, Nora; Thomas, Karluss

    2009-01-01

    Nanotechnology, the commercial development of engineered nanomaterials, promises breakthrough innovations by enhancing the performance of existing consumer products and enabling development of new devices, architectures, and applications. Although these materials and applications are being developed at an explosive pace, a fundamental understanding of any potential human health and environmental risks resulting from exposure throughout the lifecycle of these materials has not advanced as rapidly. Past experience has demonstrated that successful introduction of a new technology occurs more readily if it is precipitated by a robust appreciation for any inherent risks associated with the technology. Such understanding allows the timely development of occupational and consumer exposure standards that might be needed to protect human health and the environment. Although risk is recognized as the product of hazard and exposure, too often exposure patterns are poorly characterized, and risk is based primarily or exclusively on the hazard characterization. The extent of exposure to nanomaterials in currently available commercial products is relatively unknown. Given the number of commercial products that claim to contain engineered nanomaterials, it is possible that human and environmental exposure to these materials is widespread. This paper is intended to highlight the importance of exposure assessment for determining the potential risks of nanomaterials. In essence, this is a call to action to the community of exposure scientists, toxicologists, and risk assessors to develop, consider, and incorporate requisite exposure information in the risk assessment of nanomaterials. Without an integrated approach, it will be difficult to meaningfully assess the risks of nanomaterials, realize their potential benefits, and foster their sustainable development. PMID:20049808

  11. Assessing the mutagenic activities of smoke from different cigarettes in direct exposure experiments using the modified Ames Salmonella assay.

    PubMed

    Ishikawa, Shinkichi; Kanemaru, Yuki; Nara, Hidenori; Erami, Kazuo; Nagata, Yasufumi

    2016-06-01

    The Ames assay is useful for evaluating the mutagenic potentials of chemicals, and it has been used to evaluate the mutagenic potential of cigarette smoke (CS). In vitro direct exposure systems have been developed to mimic CS exposure in the human respiratory tract, and the Ames assay has been used with such systems. Ames tests were performed using the Vitrocell(®) direct exposure system in this study. The mutagenic potentials of whole mainstream CS and gas/vapor phase fractions produced by conventional combustible cigarettes under two smoking regimens were compared. Salmonella Typhimurium TA98 and TA100 were used with and without metabolic activation, and the number of revertants induced by exposure to each CS was determined. The amount of smoke particles to which cells were exposed were also determined, and dose-response curves describing the relationships between exposure to smoke particles and the number of revertants induced were plotted. The slopes of linear regressions of the dose-response curves were determined, and the slope for each CS was used as a mutagenic activity index for that CS. A new heated cigarette was also tested and smoke from the heated cigarette had a lower mutagenic activity in TA98 and TA100 with metabolic activation than did the conventional CS. The results indicate that the direct exposure system and the Ames test can be used to determine the mutagenic potentials of CS produced by different cigarettes under different conditions (i.e., using different Salmonella Typhimurium strains with and without metabolic activation, and using different smoking conditions). PMID:27265375

  12. Neutral red retention by lysosomes from earthworm (Lumbricus rubellus) coelomocytes: A simple biomarker of exposure to soil copper

    SciTech Connect

    Weeks, J.M.; Svendsen, C.

    1996-10-01

    A simple subcellular histochemical staining technique employing the lysosomal probe neutral red has been developed for use with the epiendogeic earthworm Lumbricus rubellus Hoffmeister. Coelomocytes extracted from the coelomic cavity of earthworms into an isotonic earthworm Ringer solution were allowed to adhere to a microscope slide for 30 s before the application of a neutral red dye. This red dye was rapidly accumulated within the lysosomes. Observation of the loss of this dye from these lysosomes into the surrounding cytosol has enabled the quantification of the degree of lysosomal damage caused to earthworms with exposure to an increasing range of soil copper concentrations, in both laboratory and mesocosm studies. This simple in vitro biomarker has potential for the rapid assessment of the toxic effects to earthworms from soils contaminated with heavy metals and metalloids.

  13. Effects of zinc exposure on earthworms, Lumbricus terrestris, in an artificial soil.

    PubMed

    Lev, Steven M; Matthies, Nick; Snodgrass, Joel W; Casey, Ryan E; Ownby, David R

    2010-06-01

    Earthworms have the potential to act as trophic links for pollutants that accumulate in urban soils. However, many pollutants may act as micronutrients at low concentrations and toxins at higher concentration. When pollutants are also micronutrients, bioaccumulations may initially increase trophic transfer as pollutant concentration increase, but at higher levels toxic effects may limit population size and the potential for trophic transfer. We found support for this model among earthworms exposed to a range of soil Zn levels. Worms showed increasing bioaccumulation of Zn with increasing Zn soil concentrations, but at higher Zn levels worm growth rates decreased. PMID:20431863

  14. Effects of feral horses in Great Basin landscapes on soils and ants: Direct and indirect mechanisms

    USGS Publications Warehouse

    Beever, E.A.; Herrick, J.E.

    2006-01-01

    We compared soil-surface penetration resistance and abundance of ant mounds at 12 western Great Basin sites (composed of 19 plots) either grazed by feral horses (Equus caballus) or having had horses removed for the last 10–14 years. Across this broad spatial domain (3.03 million ha), we minimized confounding due to abiotic factors by selecting horse-occupied and horse-removed sites with similar aspect, slope, fire history, grazing pressure by cattle (minimal to none), and dominant vegetation (Artemisia tridentata). During both 1997 and 1998, we found 2.2–8.4 times greater abundance of ant mounds and 3.0–15.4 times lower penetration resistance in soil surfaces at horse-removed sites. In 1998, thatched Formica ant mounds, which existed predominately at high elevations, were 3.3 times more abundant at horse-removed sites, although abundance varied widely among sites within treatments. Several types of analyses suggested that horses rather than environmental variability were the primary source of treatment differences we observed in ecosystem components. Tests of several predictions suggest that alterations occurred through not only direct effects, but also indirect effects and potentially feedback loops. Free-roaming horses as well as domestic grazers should be considered in conservation planning and land management in the Great Basin, an ecoregion that represents both an outstanding conservation opportunity and challenge.

  15. Evaluation of the potential of soil remediation by direct multi-channel pulsed corona discharge in soil.

    PubMed

    Wang, Tie Cheng; Qu, Guangzhou; Li, Jie; Liang, Dongli

    2014-01-15

    A novel approach, named multi-channel pulsed corona discharge in soil, was developed for remediating organic pollutants contaminated soil, with p-nitrophenol (PNP) as the model pollutant. The feasibility of PNP degradation in soil was explored by evaluating effects of pulse discharge voltage, air flow rate and soil moisture on PNP degradation. Based on roles of chemically active species and evolution of degradation intermediates, PNP degradation processes were discussed. Experimental results showed that about 89.4% of PNP was smoothly degraded within 60min of discharge treatment at pulse discharge voltage 27kV, soil moisture 5% and air flow rate 0.8Lmin(-1), and the degradation process fitted the first-order kinetic model. Increasing pulse discharge voltage was found to be favorable for PNP degradation, but not for energy yield. There existed appropriate air flow rate and soil moisture for obtaining gratifying PNP degradation efficacy. Roles of radical scavenger and measurement of active species suggested that ozone, H2O2, and OH radicals played very important roles in PNP degradation. CN bond in PNP molecule was cleaved, and the main intermediate products such as hydroquinone, benzoquinone, catechol, phenol, acetic acid, formic acid, oxalic acid, NO2(-) and NO3(-) were identified. Possible pathway of PNP degradation in soil in such a system was proposed. PMID:24295768

  16. Assessing the probability of infection by Salmonella due to sewage sludge use in agriculture under several exposure scenarios for crops and soil ingestion.

    PubMed

    Krzyzanowski, Flávio; de Souza Lauretto, Marcelo; Nardocci, Adelaide Cássia; Sato, Maria Inês Zanoli; Razzolini, Maria Tereza Pepe

    2016-10-15

    A deeper understanding about the risks involved in sewage sludge practice in agriculture is required. The aims of the present study were to determine the annual risk of infection of consuming lettuce, carrots and tomatoes cultivated in soil amended with sewage sludge. The risk to agricultural workers of accidental ingestion of sludge or amended soil was also investigated. A Quantitative Microbial Risk Assessment was conducted based on Salmonella concentrations from five WWTPs were used to estimate the probability of annual infection associated with crops and soil ingestion. The risk of infection was estimated for nine exposure scenarios considering concentration of the pathogen, sewage sludge dilution in soil, variation of Salmonella concentration in soil, soil attachment to crops, seasonal average temperatures, hours of post-harvesting exposure, Salmonella regrowth in lettuce and tomatoes, Salmonella inhibition factor in carrots, crop ingestion and frequency of exposure, sludge/soil ingestion by agricultural workers and frequency of exposure. Annual risks values varied across the scenarios evaluated. Highest values of annual risk were found for scenarios in which the variation in the concentration of Salmonella spp. in both soil and crops (scenario 1) and without variation in the concentration of Salmonella spp. in soil and variation in crops (scenario 3) ranging from 10(-3) to 10(-2) for all groups considered. For agricultural workers, the highest annual risks of infection were found when workers applied sewage sludge to agricultural soils (2.26×10(-2)). Sensitivity analysis suggests that the main drivers for the estimated risks are Salmonella concentration and ingestion rate. These risk values resulted from conservative scenarios since some assumptions were derived from local or general studies. Although these scenarios can be considered conservative, the sensitivity analysis yielded the drivers of the risks, which can be useful for managing risks from the

  17. Direct and indirect exposure to horse: risk for sensitization and asthma.

    PubMed

    Liccardi, Gennaro; Emenius, Gunnel; Merritt, Anne-Sophie; Salzillo, Antonello; D'Amato, Maria; D'Amato, Gennaro

    2012-10-01

    Most studies on the sensitization to horse allergens in populations without professional exposure have been carried out in geographical areas where the rate of horse ownership is high and horse riding is popular. Very few studies have been carried out in populations living in large urban areas. This gap in the literature probably reflects the widespread view that prevalence of horse-related allergy is low in urban populations because the latter are not regularly exposed to horses. On the contrary, we suggest that urban areas constitute a model useful to study potential modalities of exposure and sensitization to horse allergen by other routes of exposure than horse-riding. In this article, we describe the risks related to various modalities of exposure to horse allergen, clinical aspects of airway sensitization to horse allergens in patients living in urban areas, and non-occupational exposure to horse allergen. In addition, we illuminate some aspects related to dispersion of horse allergens from sources such as stables to indoor environments. PMID:22717671

  18. Accumulated metal speciation in earthworm populations with multigenerational exposure to metalliferous soils: cell fractionation and high-energy synchrotron analyses.

    PubMed

    Andre, Jane; Charnock, John; Stürzenbaum, Stephen R; Kille, Peter; Morgan, A John; Hodson, Mark E

    2009-09-01

    Predicting metal bioaccumulation and toxicity in soil organisms is complicated by site-specific biotic and abiotic parameters. In this study we exploited tissue fractionation and digestion techniques, combined with X-ray absorption spectroscopy (XAS), to investigate the whole-body and subcellular distributions, ligand affinities, and coordination chemistry of accumulated Pb and Zn in field populations of the epigeic earthworm Lumbricus rubellus inhabiting three contrasting metalliferous and two unpolluted soils. Our main findings were (i) earthworms were resident in soils with concentrations of Pb and Zn ranging from 1200 to 27,000 mg kg(-1) and 200 to 34,000 mg kg(-1), respectively; (ii) Pb and Zn primarily accumulated in the posterior alimentary canal in nonsoluble subcellular fractions of earthworms; (iii) site-specific differences in the tissue and subcellular partitioning profiles of populations were observed, with earthworms from a calcareous site partitioning proportionally more Pb to their anterior body segments and Zn to the chloragosome-rich subcellular fraction than their acidic-soil inhabiting counterparts; (iv) XAS indicated that the interpopulation differences in metal partitioning between organs were not accompanied by qualitative differences in ligand-binding speciation, because crystalline phosphate-containing pyromorphite was a predominant chemical species in the whole-worm tissues of all mine soil residents. Differences in metal (Pb, Zn) partitioning at both organ and cellular levels displayed by field populations with protracted histories of metal exposures may reflect theirinnate ecophysiological responses to essential edaphic variables, such as Ca2+ status. These observations are highly significant in the challenging exercise of interpreting holistic biomarker data delivered by "omic" technologies. PMID:19764255

  19. Metal contamination of home gardens soils and cultivated vegetables in the province of Brescia, Italy: Implications for human exposure

    PubMed Central

    Ferri, Roberta; Hashim, Dana; Smith, Donald R.; Guazzetti, Stefano; Donna, Filippo; Ferretti, Enrica; Curatolo, Michele; Moneta, Caterina; Beone, Gian Maria; Lucchini, Roberto G.

    2015-01-01

    Background For the past century, ferroalloy industries in Brescia province, Italy produced particulate emissions enriched in manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), chromium (Cr), iron (Fe), aluminum (Al). This study assessed metal concentrations in soil and vegetables of regions with varying ferroalloy industrial activity levels. Methods Home gardens (n=63) were selected in three regions of varying ferroalloy plant activity duration in Brescia province. Total soil metal concentration and extractability were measured by X-ray fluorescence (XRF), aqua regia extraction, and modified Community Bureau of Reference (BCR) sequential extraction. Unwashed and washed spinach and turnips cultivated in the same gardens were analyzed for metal concentrations by flame atomic absorption spectrometry. Results Median soil Al, Cd, Fe, Mn, Pb, and Zn concentrations were significantly higher in home gardens near ferroalloy plants compared to reference home gardens. The BCR method yielded the most mobile soil fraction (the sum of extractable metals in Fractions 1 and 2) and all metal concentrations were higher in ferroalloy plant areas. Unwashed spinach showed higher metal concentrations compared to washed spinach. However, some metals in washed spinach were higher in the reference area likely due to history of agricultural product use. Over 60% of spinach samples exceeded the 2- to 4-fold Commission of European Communities and Codex Alimentarius Commission maximum Pb concentrations, and 10% of the same spinach samples exceeded 2- to 3-fold maximum Cd concentrations set by both organizations. Turnip metal concentrations were below maximum standard reference values. Conclusions Prolonged industrial emissions increase median metal concentrations and most soluble fractions (BCR F1+F2) in home garden soils near ferroalloy plants. Areas near ferroalloy plant sites had spinach Cd and Pb metal concentrations several-fold above maximum standard references. We

  20. Operation of the computer model for direct atomic oxygen exposure of Earth satellites

    NASA Technical Reports Server (NTRS)

    Bourassa, R. J.; Gruenbaum, P. E.; Gillis, J. R.; Hargraves, C. R.

    1995-01-01

    One of the primary causes of material degradation in low Earth orbit (LEO) is exposure to atomic oxygen. When atomic oxygen molecules collide with an orbiting spacecraft, the relative velocity is 7 to 8 km/sec and the collision energy is 4 to 5 eV per atom. Under these conditions, atomic oxygen may initiate a number of chemical and physical reactions with exposed materials. These reactions contribute to material degradation, surface erosion, and contamination. Interpretation of these effects on materials and the design of space hardware to withstand on-orbit conditions requires quantitative knowledge of the atomic oxygen exposure environment. Atomic oxygen flux is a function of orbit altitude, the orientation of the orbit plan to the Sun, solar and geomagnetic activity, and the angle between exposed surfaces and the spacecraft heading. We have developed a computer model to predict the atomic oxygen exposure of spacecraft in low Earth orbit. The application of this computer model is discussed.

  1. Exposure assessment of heavy metals on abandoned metal mine areas by ingestion of soil, crop plant and groundwater

    NASA Astrophysics Data System (ADS)

    Lee, J.-S.; Chon, H.-T.

    2003-05-01

    In order to assess the risk of adverse health effects on human exposure to arsenic and heavy metals influence by past mining activities, environmental geochemical survey was undertaken in the abandoned metal mine areas (Dongil Au-Ag-Cu-Zn mine, Okdong Cu-Pb-Zn mine, Myungbong Au-Ag mine). Arsenic and other heavy metals were highly elevated in the tailings from the Dongil mine (8,720 As mg/kg, 5.9 Cd mg/kg, 3,610 Cu mg/kg, 5,850 Pb mg/kg, 630 Zn mg/kg). Heavy metals except As from the Okdong mine (53.6 Cd mg/kg, 910 Cu mg/kg, 1,590 Pb mg/kg, 5,720 Zn mg/kg) and As from the Myungbong mine (5,810 As mg/kg) were also elevated. Elevated levels of As, Cd and Zn were also found in agricultural soils from these mine areas. The H.I. (hazard index) values of As and Cd from the Dongil, the Okdong and Myungbong mine areas are higher than 1.0. Therefore, toxic risk for As and Cd exist via exposure (ingestion) of contaminated soil, groundwater and rice grain in these mine areas.

  2. Direction of Influence between Posttraumatic and Depressive Symptoms during Prolonged Exposure Therapy among Children and Adolescents

    ERIC Educational Resources Information Center

    Aderka, Idan M.; Foa, Edna B.; Applebaum, Edna; Shafran, Naama; Gilboa-Schechtman, Eva

    2011-01-01

    Objective: Our objective in the present study was to examine the temporal sequencing of posttraumatic and depressive symptoms during prolonged exposure therapy for posttraumatic stress disorder (PTSD) among children and adolescents. Method: Participants were 73 children and adolescents (56.2% female) between the ages of 8 and 18. Participants…

  3. Direct Vocabulary Instruction in Preschool: A Comparison of Extended Instruction, Embedded Instruction, and Incidental Exposure

    ERIC Educational Resources Information Center

    Loftus-Rattan, Susan M.; Mitchell, Alison M.; Coyne, Michael D.

    2016-01-01

    Based on its coincidence with a significant period in language development for children, preschool provides a favorable setting to foster vocabulary growth. The purpose of this study was to evaluate the effectiveness of two instructional conditions and an incidental exposure condition for teaching targeted vocabulary words to preschool students…

  4. Gamma-ray exposure from neutron-induced radionuclides in soil in Hiroshima and Nagasaki based on DS02 calculations.

    PubMed

    Imanaka, Tetsuji; Endo, Satoru; Tanaka, Kenichi; Shizuma, Kiyoshi

    2008-07-01

    As a result of joint efforts by Japanese, US and German scientists, the Dosimetry System 2002 (DS02) was developed as a new dosimetry system, to evaluate individual radiation dose to atomic bomb survivors in Hiroshima and Nagasaki. Although the atomic bomb radiation consisted of initial radiation and residual radiation, only initial radiation was reevaluated in DS02 because, for most survivors in the life span study group, the residual dose was negligible compared to the initial dose. It was reported, however, that there were individuals who entered the city at the early stage after the explosion and experienced hemorrhage, diarrhea, etc., which were symptoms of acute radiation syndrome. In this study, external exposure due to radionuclides induced in soil by atomic bomb neutrons was reevaluated based on DS02 calculations, as a function of both the distance from the hypocenters and the elapsed time after the explosions. As a result, exposure rates of 6 and 4 Gy h(-1) were estimated at the hypocenter at 1 min after the explosion in Hiroshima and Nagasaki, respectively. These exposure rates decreased rapidly by a factor of 1,000 1 day later, and by a factor of 1 million 1 week later. Maximum cumulative exposure from the time of explosion was 1.2 and 0.6 Gy at the hypocenters in Hiroshima and Nagasaki, respectively. Induced radiation decreased also with distance from the hypocenters, by a factor of about 10 at 500 m and a factor of three to four hundreds at 1,000 m. Consequently, a significant exposure due to induced radiation is considered feasible to those who entered the area closer to a distance of 1,000 m from the hypocenters, within one week after the bombing. PMID:18368418

  5. Coping with copper: legacy effect of copper on potential activity of soil bacteria following a century of exposure.

    PubMed

    Nunes, Inês; Jacquiod, Samuel; Brejnrod, Asker; Holm, Peter E; Johansen, Anders; Brandt, Kristian K; Priemé, Anders; Sørensen, Søren J

    2016-11-01

    Copper has been intensively used in industry and agriculture since mid-18(th) century and is currently accumulating in soils. We investigated the diversity of potential active bacteria by 16S rRNA gene transcript amplicon sequencing in a temperate grassland soil subjected to century-long exposure to normal (∼15 mg kg(-1)), high (∼450 mg kg(-1)) or extremely high (∼4500 mg kg(-1)) copper levels. Results showed that bioavailable copper had pronounced impacts on the structure of the transcriptionally active bacterial community, overruling other environmental factors (e.g. season and pH). As copper concentration increased, bacterial richness and evenness were negatively impacted, while distinct communities with an enhanced relative abundance of Nitrospira and Acidobacteria members and a lower representation of Verrucomicrobia, Proteobacteria and Actinobacteria were selected. Our analysis showed the presence of six functional response groups (FRGs), each consisting of bacterial taxa with similar tolerance response to copper. Furthermore, the use of FRGs revealed that specific taxa like the genus Nitrospira and several Acidobacteria groups could accurately predict the copper legacy burden in our system, suggesting a potential promising role as bioindicators of copper contamination in soils. PMID:27543319

  6. Adverse Birth Outcomes and Maternal Exposure to Trichloroethylene and Tetrachloroethylene through Soil Vapor Intrusion in New York State

    PubMed Central

    Lewis-Michl, Elizabeth L.; Gomez, Marta I.

    2011-01-01

    Background: Industrial spills of volatile organic compounds (VOCs) in Endicott, New York (USA), have led to contamination of groundwater, soil, and soil gas. Previous studies have reported an increase in adverse birth outcomes among women exposed to VOCs in drinking water. Objective: We investigated the prevalence of adverse birth outcomes among mothers exposed to trichloroethylene (TCE) and tetrachloroethylene [or perchloroethylene (PCE)] in indoor air contaminated through soil vapor intrusion. Methods: We examined low birth weight (LBW), preterm birth, fetal growth restriction, and birth defects among births to women in Endicott who were exposed to VOCs, compared with births statewide. We used Poisson regression to analyze births and malformations to estimate the association between maternal exposure to VOCs adjusting for sex, mother’s age, race, education, parity, and prenatal care. Two exposure areas were identified based on environmental sampling data: one area was primarily contaminated with TCE, and the other with PCE. Results: In the TCE-contaminated area, adjusted rate ratios (RRs) were significantly elevated for LBW [RR = 1.36; 95% confidence interval (CI): 1.07, 1.73; n = 76], small for gestational age (RR = 1.23; 95% CI: 1.03, 1.48; n = 117), term LBW (RR = 1.68; 95% CI: 1.20, 2.34; n = 37), cardiac defects (RR = 2.15; 95% CI: 1.27, 3.62; n = 15), and conotruncal defects (RR = 4.91; 95% CI: 1.58, 15.24; n = 3). In the PCE-contaminated area, RRs for cardiac defects (five births) were elevated but not significantly. Residual socioeconomic confounding may have contributed to elevations of LBW outcomes. Conclusions: Maternal residence in both areas was associated with cardiac defects. Residence in the TCE area, but not the PCE area, was associated with LBW and fetal growth restriction. PMID:22142966

  7. Direct Measurement of Perchlorate Exposure Biomarkers in a Highly Exposed Population: A Pilot Study

    PubMed Central

    Wong, Michelle; Copan, Lori; Olmedo, Luis; Patton, Sharyle; Haas, Robert; Atencio, Ryan; Xu, Juhua; Valentin-Blasini, Liza

    2011-01-01

    Exposure to perchlorate is ubiquitous in the United States and has been found to be widespread in food and drinking water. People living in the lower Colorado River region may have perchlorate exposure because of perchlorate in ground water and locally-grown produce. Relatively high doses of perchlorate can inhibit iodine uptake and impair thyroid function, and thus could impair neurological development in utero. We examined human exposures to perchlorate in the Imperial Valley among individuals consuming locally grown produce and compared perchlorate exposure doses to state and federal reference doses. We collected 24-hour urine specimen from a convenience sample of 31 individuals and measured urinary excretion rates of perchlorate, thiocyanate, nitrate, and iodide. In addition, drinking water and local produce were also sampled for perchlorate. All but two of the water samples tested negative for perchlorate. Perchlorate levels in 79 produce samples ranged from non-detect to 1816 ppb. Estimated perchlorate doses ranged from 0.02 to 0.51 µg/kg of body weight/day. Perchlorate dose increased with the number of servings of dairy products consumed and with estimated perchlorate levels in produce consumed. The geometric mean perchlorate dose was 70% higher than for the NHANES reference population. Our sample of 31 Imperial Valley residents had higher perchlorate dose levels compared with national reference ranges. Although none of our exposure estimates exceeded the U. S. EPA reference dose, three participants exceeded the acceptable daily dose as defined by bench mark dose methods used by the California Office of Environmental Health Hazard Assessment. PMID:21394205

  8. Direct measurement of perchlorate exposure biomarkers in a highly exposed population: a pilot study.

    PubMed

    English, Paul; Blount, Ben; Wong, Michelle; Copan, Lori; Olmedo, Luis; Patton, Sharyle; Haas, Robert; Atencio, Ryan; Xu, Juhua; Valentin-Blasini, Liza

    2011-01-01

    Exposure to perchlorate is ubiquitous in the United States and has been found to be widespread in food and drinking water. People living in the lower Colorado River region may have perchlorate exposure because of perchlorate in ground water and locally-grown produce. Relatively high doses of perchlorate can inhibit iodine uptake and impair thyroid function, and thus could impair neurological development in utero. We examined human exposures to perchlorate in the Imperial Valley among individuals consuming locally grown produce and compared perchlorate exposure doses to state and federal reference doses. We collected 24-hour urine specimen from a convenience sample of 31 individuals and measured urinary excretion rates of perchlorate, thiocyanate, nitrate, and iodide. In addition, drinking water and local produce were also sampled for perchlorate. All but two of the water samples tested negative for perchlorate. Perchlorate levels in 79 produce samples ranged from non-detect to 1816 ppb. Estimated perchlorate doses ranged from 0.02 to 0.51 µg/kg of body weight/day. Perchlorate dose increased with the number of servings of dairy products consumed and with estimated perchlorate levels in produce consumed. The geometric mean perchlorate dose was 70% higher than for the NHANES reference population. Our sample of 31 Imperial Valley residents had higher perchlorate dose levels compared with national reference ranges. Although none of our exposure estimates exceeded the U. S. EPA reference dose, three participants exceeded the acceptable daily dose as defined by bench mark dose methods used by the California Office of Environmental Health Hazard Assessment. PMID:21394205

  9. Potential use of the plant antioxidant network for environmental exposure assessment of heavy metals in soils.

    PubMed

    Meers, E; Ruttens, A; Geebelen, W; Vangronsveld, J; Samson, R; Vanbroekhoven, K; Vandegehuchte, M; Diels, L; Tack, F M G

    2006-09-01

    In recent years, awareness has risen that the total soil content of pollutants by itself does not suffice to fully assess the potential ecotoxicological risks involved. Chemical analysis will require to be complemented with biological assays in a multidisciplinary approach towards site specific ecological risk assessment (SS-ERA). This paper evaluates the potential use of the plants' antioxidant response to metal-induced oxidative stress to provide a sensitive biological assay in SS-ERA. To this end, plants of Phaseolus vulgaris were grown for two weeks on 15 soils varying in contamination level. Morphological parameters and enzymatic plant responses were measured upon harvest. Foliar concentrations of the (heavy) metals Al, Cu, Cd, Cr, Fe, Mn, Ni, Pb, Zn were also determined. Metal mobility in the soil was further assessed by determining soil solution and NH4OAc extractable levels. In general more significant correlations were observed between plant responses and foliar metal concentrations or exchangeable/soluble levels than between plant responses and the total soil content. The study demonstrates the potential use of the plants' antioxidant defence mechanisms to assess substrate phytotoxicity for application in SS-ERA protocols. However, the system, based on calculation of a soil Phytotoxicity Index (PI), will require adaptation and fine-tuning to meet the specific needs for this type of environmental monitoring. Large variation was observed in phytotoxicity classification based on the various test parameters. The thresholds for classification of the various morphological and enzymatic response parameters may require adaptation according to parameter stress sensitivity in order to decrease the observed variation. The use of partial PI's (leaves and roots separately) may in addition increase the sensitivity of the system since some metals show specific effects in one of both organs only. Loss of biological functionality of enzymes, as was observed for ICDH in

  10. Direct Assessment of Viral Diversity in Soils by Random PCR Amplification of Polymorphic DNA

    PubMed Central

    Srinivasiah, Sharath; Lovett, Jacqueline; Polson, Shawn; Bhavsar, Jaysheel; Ghosh, Dhritiman; Roy, Krishnakali; Fuhrmann, Jeffry J.; Radosevich, Mark

    2013-01-01

    Viruses are the most abundant and diverse biological entities within soils, yet their ecological impact is largely unknown. Defining how soil viral communities change with perturbation or across environments will contribute to understanding the larger ecological significance of soil viruses. A new approach to examining the composition of soil viral communities based on random PCR amplification of polymorphic DNA (RAPD-PCR) was developed. A key methodological improvement was the use of viral metagenomic sequence data for the design of RAPD-PCR primers. This metagenomically informed approach to primer design enabled the optimization of RAPD-PCR sensitivity for examining changes in soil viral communities. Initial application of RAPD-PCR viral fingerprinting to soil viral communities demonstrated that the composition of autochthonous soil viral assemblages noticeably changed over a distance of meters along a transect of Antarctic soils and across soils subjected to different land uses. For Antarctic soils, viral assemblages segregated upslope from the edge of dry valley lakes. In the case of temperate soils at the Kellogg Biological Station, viral communities clustered according to land use treatment. In both environments, soil viral communities changed along with environmental factors known to shape the composition of bacterial host communities. Overall, this work demonstrates that RAPD-PCR fingerprinting is an inexpensive, high-throughput means for addressing first-order questions of viral community dynamics within environmental samples and thus fills a methodological gap between narrow single-gene approaches and comprehensive shotgun metagenomic sequencing for the analysis of viral community diversity. PMID:23793630

  11. Direct/Delayed Response Project: Definition of soil-sampling classes and selection of sampling sites for the Northeast

    SciTech Connect

    Lee, J.J.; Marmorek, D.R.; Thornton, K.W.; Stevens, D.L.; Lammers, D.A.

    1989-04-01

    The Direct/Delayed Response Project (DDRP) was designed and implemented to estimate the number of lakes and streams that might become acidic in three regions due to current or altered levels of acidic deposition. As part of DDRP, 145 watersheds in the northeast US were mapped at 1:24,000 for soils, vegetation, depth to bedrock, and bedrock geology. About 600 soils were identified during mapping. These were grouped into 38 soil-sampling classes. Each of these was sampled about 8 times across the region, so that regional means and standard deviations of soil properties could be computed for each class. The regional soil data will be used with the soil maps to estimate soil properties for each watershed. The watershed estimates will be used in the array of DDRP models to estimate future effects of acidic deposition on lakes in the northeast. The sampling classes were developed at a workshop held in Corvallis, Oregon July 16-18, 1985. This report documents the process and decisions of the workshop.

  12. Direct interspecies electron transfer accelerates syntrophic oxidation of butyrate in paddy soil enrichments.

    PubMed

    Li, Huijuan; Chang, Jiali; Liu, Pengfei; Fu, Li; Ding, Dewen; Lu, Yahai

    2015-05-01

    Syntrophic interaction occurs during anaerobic fermentation of organic substances forming methane as the final product. H2 and formate are known to serve as the electron carriers in this process. Recently, it has been shown that direct interspecies electron transfer (DIET) occurs for syntrophic CH4 production from ethanol and acetate. Here, we constructed paddy soil enrichments to determine the involvement of DIET in syntrophic butyrate oxidation and CH4 production. The results showed that CH4 production was significantly accelerated in the presence of nanoFe3 O4 in all continuous transfers. This acceleration increased with the increase of nanoFe3 O4 concentration but was dismissed when Fe3 O4 was coated with silica that insulated the mineral from electrical conduction. NanoFe3 O4 particles were found closely attached to the cell surfaces of different morphology, thus bridging cell connections. Molecular approaches, including DNA-based stable isotope probing, revealed that the bacterial Syntrophomonadaceae and Geobacteraceae, and the archaeal Methanosarcinaceae, Methanocellales and Methanobacteriales, were involved in the syntrophic butyrate oxidation and CH4 production. Among them, the growth of Geobacteraceae strictly relied on the presence of nanoFe3 O4 and its electrical conductivity in particular. Other organisms, except Methanobacteriales, were present in enrichments regardless of nanoFe3 O4 amendment. Collectively, our study demonstrated that the nanoFe3 O4 -facilitated DIET occurred in syntrophic CH4 production from butyrate, and Geobacter species played the key role in this process in the paddy soil enrichments. PMID:25059331

  13. DNA Damage in Vicia faba by Exposure to Agricultural Soils from Tlaxcala, Mexico.

    PubMed

    Juárez-Santacruz, L; García-Nieto, E; García-Gallegos, E; Romo-Gómez, C; Ortiz-Ortiz, E; Costilla-Salazar, R; Luna-Zendejas, H S

    2015-12-01

    The aim of this research was to quantify some POPs, such as p,p' DDT, p,p' DDE, and PCBs in agricultural soils of Tlaxcala, Mexico and evaluate their capacity for eliciting DNA damage, using Vicia faba as bioindicator. The values of ΣDDTs and ΣPCBs ranged from 8-24 to 118-26,983 µg/kg, respectively. The samples T1 (HQ = 9.3) and T2 (HQ = 53.9) showed concentrations of ΣPCBs higher than Canadian guidelines (SQGE = 500 µg/kg). The genotoxicity testing produced percentages of DNA fragmentation higher than negative control and statistically significant (p < 0.05), both in agricultural soils and organic extracts. The soils T2, T3, N4, and N5 showed a DICA from 2.6 to 3.1 times, statistically higher (p < 0.05) than negative control. In general, the agricultural soils have greater genotoxic capacity than the organic extracts, suggesting a potential risk to biota that depends upon this ecosystem. PMID:26385693

  14. Chorioamnionitis-induced fetal gut injury is mediated by direct gut exposure of inflammatory mediators or by lung inflammation

    PubMed Central

    Wolfs, Tim G. A. M.; Kramer, Boris W.; Thuijls, Geertje; Kemp, Matthew W.; Saito, Masatoshi; Willems, Monique G. M.; Senthamarai-Kannan, Paranthaman; Newnham, John P.; Jobe, Alan H.

    2014-01-01

    Intra-amniotic exposure to proinflammatory agonists causes chorioamnionitis and fetal gut inflammation. Fetal gut inflammation is associated with mucosal injury and impaired gut development. We tested whether this detrimental inflammatory response of the fetal gut results from a direct local (gut derived) or an indirect inflammatory response mediated by the chorioamnion/skin or lung, since these organs are also in direct contact with the amniotic fluid. The gastrointestinal tract was isolated from the respiratory tract and the amnion/skin epithelia by fetal surgery in time-mated ewes. Lipopolysaccharide (LPS) or saline (controls) was selectively infused in the gastrointestinal tract, trachea, or amniotic compartment at 2 or 6 days before preterm delivery at 124 days gestation (term 150 days). Gastrointestinal and intratracheal LPS exposure caused distinct inflammatory responses in the fetal gut. Inflammatory responses could be distinguished by the influx of leukocytes (MPO+, CD3+, and FoxP3+ cells), tumor necrosis factor-α, and interferon-γ expression and differential upregulation of mRNA levels for Toll-like receptor 1, 2, 4, and 6. Fetal gut inflammation after direct intestinal LPS exposure resulted in severe loss of the tight junctional protein zonula occludens protein 1 (ZO-1) and increased mitosis of intestinal epithelial cells. Inflammation of the fetal gut after selective LPS instillation in the lungs caused only mild disruption of ZO-1, loss in epithelial cell integrity, and impaired epithelial differentiation. LPS exposure of the amnion/skin epithelia did not result in gut inflammation or morphological, structural, and functional changes. Our results indicate that the detrimental consequences of chorioamnionitis on fetal gut development are the combined result of local gut and lung-mediated inflammatory responses. PMID:24458021

  15. Chorioamnionitis-induced fetal gut injury is mediated by direct gut exposure of inflammatory mediators or by lung inflammation.

    PubMed

    Wolfs, Tim G A M; Kramer, Boris W; Thuijls, Geertje; Kemp, Matthew W; Saito, Masatoshi; Willems, Monique G M; Senthamarai-Kannan, Paranthaman; Newnham, John P; Jobe, Alan H; Kallapur, Suhas G

    2014-03-01

    Intra-amniotic exposure to proinflammatory agonists causes chorioamnionitis and fetal gut inflammation. Fetal gut inflammation is associated with mucosal injury and impaired gut development. We tested whether this detrimental inflammatory response of the fetal gut results from a direct local (gut derived) or an indirect inflammatory response mediated by the chorioamnion/skin or lung, since these organs are also in direct contact with the amniotic fluid. The gastrointestinal tract was isolated from the respiratory tract and the amnion/skin epithelia by fetal surgery in time-mated ewes. Lipopolysaccharide (LPS) or saline (controls) was selectively infused in the gastrointestinal tract, trachea, or amniotic compartment at 2 or 6 days before preterm delivery at 124 days gestation (term 150 days). Gastrointestinal and intratracheal LPS exposure caused distinct inflammatory responses in the fetal gut. Inflammatory responses could be distinguished by the influx of leukocytes (MPO(+), CD3(+), and FoxP3(+) cells), tumor necrosis factor-α, and interferon-γ expression and differential upregulation of mRNA levels for Toll-like receptor 1, 2, 4, and 6. Fetal gut inflammation after direct intestinal LPS exposure resulted in severe loss of the tight junctional protein zonula occludens protein 1 (ZO-1) and increased mitosis of intestinal epithelial cells. Inflammation of the fetal gut after selective LPS instillation in the lungs caused only mild disruption of ZO-1, loss in epithelial cell integrity, and impaired epithelial differentiation. LPS exposure of the amnion/skin epithelia did not result in gut inflammation or morphological, structural, and functional changes. Our results indicate that the detrimental consequences of chorioamnionitis on fetal gut development are the combined result of local gut and lung-mediated inflammatory responses. PMID:24458021

  16. The effect of biochar in soil enzyme activities: Latest advances and future directions

    NASA Astrophysics Data System (ADS)

    Paz-Ferreiro, Jorge; Méndez, Ana; Gascó, Gabriel

    2014-05-01

    In the last years there has been an increasing interest in biochar research. Soil biological and biochemical properties have a preeminent role driving nutrient cycling and can be considered as indicators of soil quality. The information on the effects of biochar addition in soil biological activities in still scarce, although an influential number of articles have appeared lately. The aim of this work is to provide an overview of those articles dealing with the biological impact of biochar addition to soil. Studies conducted in soils in different countries differing in forming factors and fertility status are presented. The focus of this work is on how biochar interacts with soil fauna, on changes in soil biological and biochemical properties following heavy metal immobilization after biochar addition and on how these changes are important in relation to global change. Priority areas were research is needed are identified.

  17. Measurement of gamma radiation levels in soil samples from Thanjavur using γ-ray spectrometry and estimation of population exposure

    PubMed Central

    Senthilkumar, B.; Dhavamani, V.; Ramkumar, S.; Philominathan, P.

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using γ-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232Th, 238U and 40K is 42.9±9.4 Bq.kg−1, 14.7±1.7 Bq.kg−1 and 149.5±3.1 Bq.kg−1 respectively are derived from all the soil samples studied. The activity concentration of 232Th, 238U and 40K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h−1 and 59.1 nGy.h−1 with an arithmetic mean of 43.3 ±9 nGy.h−1. This value is lesser than the population weighted world-averaged of 60 nGy.h−1. Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 μSv.y−1 with an arithmetic mean of 53.1±11 μSv.y−1. The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels. PMID:20177570

  18. Measurement of gamma radiation levels in soil samples from Thanjavur using gamma-ray spectrometry and estimation of population exposure.

    PubMed

    Senthilkumar, B; Dhavamani, V; Ramkumar, S; Philominathan, P

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides (232)Th, (238)U and (40)K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using gamma-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of (232)Th, (238)U and (40)K is 42.9+/-9.4 Bq.kg(-1), 14.7+/-1.7 Bq.kg(-1) and 149.5+/-3.1 Bq.kg(-1) respectively are derived from all the soil samples studied. The activity concentration of (232)Th, (238)U and (40)K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h(-1) and 59.1 nGy.h(-1) with an arithmetic mean of 43.3 +/-9 nGy.h(-1). This value is lesser than the population weighted world-averaged of 60 nGy.h(-1). Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 muSv.y(-1) with an arithmetic mean of 53.1+/-11 muSv.y(-1). The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels. PMID:20177570

  19. Early Exposure to Direct Instruction and Subsequent Juvenile Delinquency: A Prospective Examination.

    ERIC Educational Resources Information Center

    Mills, Paulette E.; Cole, Kevin N.; Jenkins, Joseph R.; Dale, Philip S.

    2002-01-01

    A study examined juvenile delinquency outcomes for 171 children with disabilities participating in two different preschool models, one using direct instruction, the other using a cognitively oriented, child-directed model. At age 15, the groups did not differ significantly in their level of reported delinquency. (Contains references.) (Author/CR)

  20. [Medico-legal opinion in establishing "exposure to direct danger of death or grave detriment to health"].

    PubMed

    Jurek, Tomasz; Maksymowicz, Krzysztof

    2005-01-01

    This paper deals with the problem of competence of the forensic expert opinions on the exposure to "direct danger of death or grave detriment to health". According to the analysis of judicial verdicts and the comments of lawyers "direct danger" depends closely on the probability, time and number of occurrences between the behavior of the perpetrator and the threatening act. The competence of the forensic expert does not allow for the legal qualification of the act but for the assessment of from the medicolegal point of view, defining the threat and possible outcomes in a descriptive fashion. The assessment of "direct danger" should be the result of close cooperation between the judicial representative and forensic expert. PMID:15984124

  1. Iodine-129 in soils from Northern Ukraine and the retrospective dosimetry of the iodine-131 exposure after the Chernobyl accident.

    PubMed

    Michel, R; Handl, J; Ernst, T; Botsch, W; Szidat, S; Schmidt, A; Jakob, D; Beltz, D; Romantschuk, L D; Synal, H-A; Schnabel, C; López-Gutiérrez, J M

    2005-03-20

    Forty-eight soil profiles down to a depth of 40 cm were taken in Russia and Ukraine in 1995 and 1997, respectively, in order to investigate the feasibility of retrospective dosimetry of the 131I exposure after the Chernobyl accident via the long-lived 129I. The sampling sites covered areas almost not affected by fallout from the Chernobyl accident such as Moscow/Russia and the Zhitomir district in Ukraine as well as the highly contaminated Korosten and Narodici districts in Ukraine. 129I was analyzed by radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS). 127I was measured for some profiles by RNAA or ion chromatography (IC). The results for 127I demonstrated large differences in the capabilities of the soils to store iodine over long time spans. The depth profiles of 129I and of 137Cs showed large differences in the migration behavior between the two nuclides but also for each nuclide among the different sampling sites. Though it cannot be quantified how much 129I and 137Cs was lost out of the soil columns into deeper depths, the inventories in the columns were taken as proxies for the total inventories. For 129I, these inventories were at least three orders of magnitude higher than a pre-nuclear value of 0.084+/-0.017 mBq m(-2) derived from a soil profile taken in 1939 in Lutovinovo/Russia. From the samples from Moscow and Zhitomir, a pre-Chernobyl 129I inventory of (44+/-24) mBq m(-2) was determined, limiting the feasibility of 129I retrospective dosimetry to areas where the 129I inventories exceed 100 mBq m(-2). Higher average 129I inventories in the Korosten and Narodici districts of 130 and 848 mBq m(-2), respectively, allowed determination of the 129I fallout due to the Chernobyl accident. Based on the total 129I inventories and on literature data for the atomic ratio of 129I/131I=13.6+/-2.8 for the Chernobyl emissions and on aggregated dose coefficients for 131I, the thyroid exposure due to 131I after the Chernobyl

  2. Reduced persistence of the macrolide antibiotics erythromycin, clarithromycin and azithromycin in agricultural soil following several years of exposure in the field.

    PubMed

    Topp, Edward; Renaud, Justin; Sumarah, Mark; Sabourin, Lyne

    2016-08-15

    The macrolide antibiotics erythromycin, clarithromycin and azithromycin are very important in human and animal medicine, and can be entrained onto agricultural ground through application of sewage sludge or manures. In the present study, a series of replicated field plots were left untreated or received up to five annual spring applications of a mixture of three drugs to achieve a nominal concentration for each of 10 or 0.1mgkg(-1) soil; the latter an environmentally relevant concentration. Soil samples were incubated in the laboratory, and supplemented with antibiotics to establish the dissipation kinetics of erythromycin and clarithromycin using radioisotope methods, and azithromycin using HPLC-MS/MS. All three drugs were dissipated significantly more rapidly in soils with a history of field exposure to 10mgkg(-1) macrolides, and erythromycin and clarithromycin were also degraded more rapidly in field soil exposed to 0.1mgkg(-1) macrolides. Rapid mineralization of (14)C-labelled erythromycin and clarithromycin are consistent with biodegradation. Analysis of field soils revealed no carryover of parent compound from year to year. Azithromycin transformation products were detected consistent with removal of the desosamine and cladinose moieties. Overall, these results have revealed that following several years of exposure to macrolide antibiotics these are amenable to accelerated degradation. The potential accelerated degradation of these drugs in soils amended with manure and sewage sludge should be investigated as this phenomenon would attenuate environmental exposure and selection pressure for clinically relevant resistance. PMID:27096634

  3. Dorchester Lead-Safe Yard project: a pilot program to demonstrate low-cost, on-site techniques to reduce exposure to lead-contaminated soil.

    PubMed

    Hynes, H P; Maxfield, R; Carroll, P; Hillger, R

    2001-03-01

    Despite a general reduction in blood lead levels in children after lead was banned in gasoline and paint, lead poisoning remains an important health problem in many older urban areas. One factor that increases risk in these places is the high levels of lead in certain residential areas. A major intervention study found that reducing lead levels in urban soils results in a reduction in exposed children's blood lead levels. Removing lead from inner-city soils or reducing exposures to lead-contaminated soils typically is expensive, technologically challenging, or beyond the ability of low-income households to undertake. This project, in conjunction with residents and community-based institutions, developed a series of in situ, low-cost, low-technology measures that worked to reduce the exposure to lead-contaminated soils in one Boston, Massachusetts, neighborhood. The project demonstrated several important results. Government, universities, residents, and community based organizations can work together effectively to reduce exposures to lead in soil. Lead-contaminated soil can be mitigated at a fraction of the cost of conventional methods in ways that increase the ability of residents, community health centers, and others to have a positive impact on their neighborhoods. A lead-safe yard program can be replicated and institutionalized by municipal home de-leading programs and other community organizations. PMID:11368198

  4. Influence of soil acidification in southern Norway on the 137Cs exposure of moose?

    PubMed

    Steinnes, Eiliv; Gaare, Eldar; Engen, Steinar

    2009-06-01

    The mean (137)Cs activity concentration in 278 liver samples of moose (Alces alces) from 16 municipalities located in different parts of Norway varied within the range 43-752 Bq kg(-1) among the municipalities. In general the geographical variation corresponded to the fallout pattern produced by the Chernobyl accident. In three communities in the southernmost part of the country however the transfer factor, defined as the activity in moose liver divided by the corresponding level in surface soil, was 6.5 times higher on average than elsewhere in Norway. Possible reasons for this highly significant difference are discussed, and it is hypothesized that the apparently much higher plant uptake in the south may be related to extensive soil acidification in this area from transboundary pollution. PMID:19303135

  5. Lead exposure in young children from dust and soil in the United Kingdom

    SciTech Connect

    Thornton, I.; Watt, J.M. ); Davies, D.J.A.; Quinn, M.J. )

    1990-11-01

    A survey of metals in United Kingdom dusts and soils has confirmed widespread lead contamination with a geometric mean value for lead in surface (0-5 cm) garden soils of 266 {mu}g/g and in housedusts of 561 {mu}g/g (excluding old mining areas). A subsequent detailed survey of 97 householders in Birmingham with 2-year-old children showed dust lead loading in the home environment to be an important predictor of blood lead concentrations in young children, when both variables fell within the normal range for the UK. The total estimated lead uptake by the young child was 36 {mu}g/day of which 1 {mu}g was by inhalation and 35 {mu}g by ingestion.

  6. Comparison of radon fluxes with gamma-radiation exposure rates and soil /sup 226/Ra concentrations

    SciTech Connect

    Young, J.A.; Thomas, V.W.

    1984-04-01

    Radon fluxes and contact gamma-radiation-exposure rates were measured at the grid points of rectangular grids on three properties in Edgemont, South Dakota that were known to have deposits of residual radioactivity relatively near to the surface. The coefficient of determination, r/sup 2/, between the radon fluxes and the contact gamma-radiation-exposure rates varied from 0.89 to 0.31 for the three properties. The property having the highest fluxes and residual radioactivity of relatively uniform depth showed the highest correlation between fluxes and exposure rates, and the property having residual radioactivity that varied considerably in depth showed the lowest. Correlations between fluxes and /sup 226/Ra concentrations measured in boreholes that varied in depth from 60 to 195 cm were lower than those between fluxes and exposure rates, indicating that exposure rates are better than /sup 226/Ra measurements for detecting elevated radon fluxes from near-surface deposits. Measurements made on one property at two different times indicated that if the average flux were determined from a large number (40) of measurements at one time, the average flux at a later time could be estimated from a few measurements using the assumption that the change in the flux at individual locations will be equal to the change in the average flux. Flux measurements around two buildings showing elevated indoor radon-daughter concentrations, but around which no residual radioactivity had been discovered by /sup 226/Ra and gamma-radiation measurements, provided no clear indication of the presence of such material, possibly because none was present.

  7. Evaluation of occupational exposure to ELF magnetic fields at power plants in Greece in the context of European directives.

    PubMed

    Christopoulou, Maria; Govari, Chrysa; Tsaprouni, Panagiota; Karabetsos, Efthymios

    2015-12-01

    The scope of this paper is to comparatively present the extremely low-frequency (ELF) measurements performed at four power plants in Greece, focusing on: (a) the worst-case exposure conditions, (b) the existence of magnetic field harmonic components, (c) the technical similarities among the power plants and (d) comparison of the measured percentages of reference levels at typical working areas in the power plants. A detailed measurement methodology is proposed, including broadband on-site inspection of the working areas, weighted averaged root-mean-square and peak values of magnetic flux density, percentage of reference levels, according to 1998 ICNIRP guidelines and harmonic analysis of the multi-frequency magnetic fields. During the analysis of the occupational exposure in all power plants, the new Directive 2013/35/EU has been taken into account. The study concludes by proposing a mapping procedure of working areas into certain zones, in order to take measures for workers safety. PMID:25614632

  8. Murine precision-cut lung slices exhibit acute responses following exposure to gasoline direct injection engine emissions.

    PubMed

    Maikawa, Caitlin L; Zimmerman, Naomi; Rais, Khaled; Shah, Mittal; Hawley, Brie; Pant, Pallavi; Jeong, Cheol-Heon; Delgado-Saborit, Juana Maria; Volckens, John; Evans, Greg; Wallace, James S; Godri Pollitt, Krystal J

    2016-10-15

    Gasoline direct injection (GDI) engines are increasingly prevalent in the global vehicle fleet. Particulate matter emissions from GDI engines are elevated compared to conventional gasoline engines. The pulmonary effects of these higher particulate emissions are unclear. This study investigated the pulmonary responses induced by GDI engine exhaust using an ex vivo model. The physiochemical properties of GDI engine exhaust were assessed. Precision cut lung slices were prepared using Balb/c mice to evaluate the pulmonary response induced by one-hour exposure to engine-out exhaust from a laboratory GDI engine operated at conditions equivalent to vehicle highway cruise conditions. Lung slices were exposed at an air-liquid interface using an electrostatic aerosol in vitro exposure system. Particulate and gaseous exhaust was fractionated to contrast mRNA production related to polycyclic aromatic hydrocarbon (PAH) metabolism and oxidative stress. Exposure to GDI engine exhaust upregulated genes involved in PAH metabolism, including Cyp1a1 (2.71, SE=0.22), and Cyp1b1 (3.24, SE=0.12) compared to HEPA filtered air (p<0.05). GDI engine exhaust further increased Cyp1b1 expression compared to filtered GDI engine exhaust (i.e., gas fraction only), suggesting this response was associated with the particulate fraction. Exhaust particulate was dominated by high molecular weight PAHs. Hmox1, an oxidative stress marker, exhibited increased expression after exposure to GDI (1.63, SE=0.03) and filtered GDI (1.55, SE=0.04) engine exhaust compared to HEPA filtered air (p<0.05), likely attributable to a combination of the gas and particulate fractions. Exposure to GDI engine exhaust contributes to upregulation of genes related to the metabolism of PAHs and oxidative stress. PMID:27369091

  9. A synthesis of current knowledge and future directions for soil magnetism research

    NASA Astrophysics Data System (ADS)

    Hannam, Jacqueline A.; Van Dam, Remke L.; Harmon, Russell S.

    2009-05-01

    Magnetic properties of soils have adverse effects on metal detectors, particularly hampering operations during clearance of landmines and unexploded ordnance. Although there is well established research in soil magnetism and modeling electromagnetic induction systems these have tended to exist in disparate disciplines. Hence, a workshop was organized to bring together researchers, academics, stakeholders and manufacturers to discuss key priorities for research and technology in a unique multidisciplinary environment. Key knowledge gaps identified include limited information on the spatial heterogeneity of soil magnetic properties in 2D and 3D, whether current models describing soil responses are appropriate for all soils and the need for compensation mechanisms in detectors to be improved. Several priorities were identified that would maximize future developments for multidisciplinary research in soil magnetism and detector technology. These include acquiring well constrained empirical data on soil electromagnetic properties and detector response over the frequency range of detectors; development of predictive models of soil magnetic properties; investigating variability of soil magnetic properties in two and three dimensions across a range of scales. Improved communication between disciplines is key to effective targeting and realization of research priorities. Possible platforms include a multidisciplinary pilot study at an appropriate site and the development of an online repository to assist dissemination of results and information.

  10. How significant to plant N nutrition is the direct consumption of soil microbes by roots?

    PubMed Central

    Hill, Paul W; Marsden, Karina A; Jones, Davey L

    2013-01-01

    Summary –The high degree to which plant roots compete with soil microbes for organic forms of nitrogen (N) is becoming increasingly apparent. This has culminated in the finding that plants may consume soil microbes as a source of N, but the functional significance of this process remains unknown. –We used 15N- and 14C-labelled cultures of soil bacteria to measure rates of acquisition of microbes by sterile wheat roots and plants growing in soil. We compared these rates with acquisition of 15N delivered as nitrate, amino acid monomer (l-alanine) and short peptide (l-tetraalanine), and the rate of decomposition of [14C] microbes by indigenous soil microbiota. –Acquisition of microbe 15N by both sterile roots and roots growing in soil was one to two orders of magnitude slower than acquisition of all other forms of 15N. Decomposition of microbes was fast enough to account for all 15N recovered, but approximately equal recovery of microbe 14C suggests that microbes entered roots intact. –Uptake of soil microbes by wheat (Triticum aestivum) roots appears to take place in soil. If wheat is typical, the importance of this process to terrestrial N cycling is probably minor in comparison with fluxes of other forms of soil inorganic and organic N. PMID:23718181

  11. Reproducible direct exposure environmental testing of metal-based magnetic media

    NASA Technical Reports Server (NTRS)

    Sides, Paul J.

    1994-01-01

    A flow geometry and flow rate for mixed flowing gas testing is proposed. Use of an impinging jet of humid polluted air can provide a uniform and reproducible exposure of coupons of metal-based magnetic media. Numerical analysis of the fluid flow and mass transfer in such as system has shown that samples confined within a distance equal to the nozzle radius on the surface of impingement are uniformly accessible to pollutants in the impinging gas phase. The critical factor is the nozzle height above the surface of impingement. In particular, the uniformity of exposure is less than plus/minus 2% for a volumetric flow rate of 1600 cm(exp 3)/minute total flow with the following specifications: For a one inch nozzle, the height of the nozzle opening above the stage should be 0.177 inches; for a 2 inch nozzle - 0.390 inches. Not only is the distribution uniform, but one can calculate the maximum delivery rate of pollutants to the samples for comparison with the observed deterioration.

  12. Different routes, same pathways: Molecular mechanisms under silver ion and nanoparticle exposures in the soil sentinel Eisenia fetida.

    PubMed

    Novo, Marta; Lahive, Elma; Díez-Ortiz, María; Matzke, Marianne; Morgan, Andrew J; Spurgeon, David J; Svendsen, Claus; Kille, Peter

    2015-10-01

    Use of nanotechnology products is increasing; with silver (Ag) nanoparticles particularly widely used. A key uncertainty surrounding the risk assessment of AgNPs is whether their effects are driven through the same mechanism of action that underlies the toxic effects of Ag ions. We present the first full transcriptome study of the effects of Ag ions and NPs in an ecotoxicological model soil invertebrate, the earthworm Eisenia fetida. Gene expression analyses indicated similar mechanisms for both silver forms with toxicity being exerted through pathways related to ribosome function, sugar and protein metabolism, molecular stress, disruption of energy production and histones. The main difference seen between Ag ions and NPs was associated with potential toxicokinetic effects related to cellular internalisation and communication, with pathways related to endocytosis and cilia being significantly enriched. These results point to a common final toxicodynamic response, but initial internalisation driven by different exposure routes and toxicokinetic mechanisms. PMID:26204059

  13. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR CALCULATING INGESTION EXPOSURE FROM DAY 4 COMPOSITE MEASUREMENTS, THE DIRECT METHOD OF EXPOSURE ESTIMATION (IIT-A-6.0)

    EPA Science Inventory

    The purpose of this SOP is to describe the procedures undertaken for calculating ingestion exposure from Day 4 composite measurements from duplicate diet using the direct method of exposure estimation. This SOP uses data that have been properly coded and certified with appropria...

  14. Occupational Exposure Assessment in Carbon Nanotube and Nanofiber Primary and Secondary Manufacturers: Mobile Direct-Reading Sampling

    PubMed Central

    DAHM, MATTHEW M.; EVANS, DOUGLAS E.; SCHUBAUER-BERIGAN, MARY K.; BIRCH, M. EILEEN; DEDDENS, JAMES A.

    2015-01-01

    Research Significance Toxicological evidence suggests the potential for a wide range of health effects from exposure to carbon nanotubes (CNTs) and carbon nanofibers (CNFs). To date, there has been much focus on the use of direct-reading instruments (DRIs) to assess multiple airborne exposure metrics for potential exposures to CNTs and CNFs due to their ease of use and ability to provide instantaneous results. Still, uncertainty exists in the usefulness and interpretation of the data. To address this gap, air-monitoring was conducted at six sites identified as CNT and CNF manufacturers or users and results were compared with filter-based metrics. Methods Particle number, respirable mass, and active surface area concentrations were monitored with a condensation particle counter, a photometer, and a diffusion charger, respectively. The instruments were placed on a mobile cart and used as area monitors in parallel with filter-based elemental carbon (EC) and electron microscopy samples. Repeat samples were collected on consecutive days, when possible, during the same processes. All instruments in this study are portable and routinely used for industrial hygiene sampling. Results Differences were not observed among the various sampled processes compared with concurrent indoor or outdoor background samples while examining the different DRI exposure metrics. Such data were also inconsistent with results for filter-based samples collected concurrently at the same sites [Dahm MM, Evans DE, Schubauer-Berigan MK et al. (2012) Occupational exposure assessment in CNT and nanofiber primary and secondary manufacturers. Ann Occup Hyg; 56: 542–56]. Significant variability was seen between these processes as well as the indoor and outdoor backgrounds. However, no clear pattern emerged linking the DRI results to the EC or the microscopy data (CNT and CNF structure counts). Conclusions Overall, no consistent trends were seen among similar processes at the various sites. The DRI

  15. Soil microbial community changes as a result of long-term exposure to a natural CO 2 vent

    NASA Astrophysics Data System (ADS)

    Oppermann, B. I.; Michaelis, W.; Blumenberg, M.; Frerichs, J.; Schulz, H. M.; Schippers, A.; Beaubien, S. E.; Krüger, M.

    2010-05-01

    The capture and geological storage of CO 2 can be used to reduce anthropogenic greenhouse gas emissions. To assess the environmental impact of potential CO 2 leakage from deep storage reservoirs on the abundance and functional diversity of microorganisms in near-surface terrestrial environments, a natural CO 2 vent (>90% CO 2 in the soil gas) was studied as an analogue. The microbial communities were investigated using lipid biomarkers combined with compound-specific stable carbon isotope analyses, the determination of microbial activities, and the use of quantitative polymerase chain reactions (Q-PCR). With this complementary set of methods, significant differences between the CO 2-rich vent and a reference site with a normal CO 2 concentration were detected. The δ 13C values of the plant and microbial lipids within the CO 2 vent demonstrate that substantial amounts of geothermal CO 2 were incorporated into the microbial, plant, and soil carbon pools. Moreover, the numbers of Archaea and Bacteria were highest at the reference site and substantially lower at the CO 2 vent. Lipid biomarker analyses, Q-PCR, and the determination of microbial activities showed the presence of CO 2-utilising methanogenic Archaea, Geobacteraceae, and sulphate-reducing Bacteria (SRB) mainly at the CO 2 vent, only minor quantities were found at the reference site. Stable carbon isotopic analyses revealed that the methanogenic Archaea and SRB utilised the vent-derived CO 2 for assimilatory biosynthesis. Our results show a shift in the microbial community towards anaerobic and acidophilic microorganisms as a consequence of the long-term exposure of the soil environment to high CO 2 concentrations.

  16. Validation of sensor-directed spatial simulated annealing soil sampling strategy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil spatial variability has a profound influence on most agronomical and environmental processes at field- and landscape-scales, including: site-specific management, vadose zone hydrology and transport, and soil quality, to mention a few. Mobile sensors are a practical means of mapping spatial vari...

  17. Design and field tests of a directly coupled waveguide-on-access-tube soil water sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sensor systems capable of monitoring soil water content can provide a useful tool for irrigation control. Current systems are limited by installation depth, labor, accuracy, and cost. Time domain reflectometry (TDR) is an approach for monitoring soil water content that relates the travel time of an ...

  18. Human exposure to trace elements through the skin by direct contact with clothing: Risk assessment

    SciTech Connect

    Rovira, Joaquim; Nadal, Martí; Schuhmacher, Marta; Domingo, José L.

    2015-07-15

    Metals in textile products and clothing are used for many purposes, such as metal complex dyes, pigments, mordant, catalyst in synthetic fabrics manufacture, synergists of flame retardants, antimicrobials, or as water repellents and odour-preventive agents. When present in textile materials, heavy metals may mean a potential danger to human health. In the present study, the concentrations of a number of elements (Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Tl, V, and Zn) were determined in skin-contact clothes. Analysed clothes were made of different materials, colours, and brands. Interestingly, we found high levels of Cr in polyamide dark clothes (605 mg/kg), high Sb concentrations in polyester clothes (141 mg/kg), and great Cu levels in some green cotton fabrics (around 280 mg/kg). Dermal contact exposure and human health risks for adult males, adult females, and for <1-year-old children were assessed. Non-carcinogenic and carcinogenic risks were below safe (HQ<1) and acceptable (<10{sup −6}) limits, respectively, according to international standards. However, for Sb, non-carcinogenic risk was above 10% of the safety limit (HQ>0.1) for dermal contact with clothes. - Highlights: • We determined in skin-contact clothes the concentrations of a number of metals. • Dermal contact exposure and health risks for adults and for 1-year-old children were assessed. • Carcinogenic risks were considered as acceptable (<10{sup −6}). • For non-carcinogenic risks, only Sb exceeded a 10% of the HQ for dermal contact with clothes.

  19. Direct and Passive Prenatal Nicotine Exposure and the Development of Externalizing Psychopathology

    ERIC Educational Resources Information Center

    Gatzke-Kopp, Lisa M.; Beauchaine, Theodore P.

    2007-01-01

    The association between maternal smoking during pregnancy and childhood antisocial outcomes has been demonstrated repeatedly across a variety of outcomes. Yet debate continues as to whether this association reflects a direct programming effect of nicotine on fetal brain development, or a phenotypic indicator of heritable liability passed from…

  20. Probabilistic assessment of environmental exposure to the polycyclic musk, HHCB and associated risks in wastewater treatment plant mixing zones and sludge amended soils in the United States.

    PubMed

    Federle, Thomas; Sun, Ping; Dyer, Scott; Kiel, Brian

    2014-09-15

    The objective of this work was to conduct an environmental risk assessment for the consumer use of the polycyclic musk, HHCB (CAS No. 1222-05-5) in the U.S. focusing on mixing zones downstream from municipal wastewater treatment plants (WWTPs) and sludge amended soils. A probabilistic exposure approach was utilized combining statistical distributions of effluent and sludge concentrations for the U.S. WWTPs with distributions of mixing zone dilution factors and sludge loading rates to soil to estimate HHCB concentrations in surface waters and sediments below WWTPs and sludge amended soils. These concentrations were then compared to various toxicity values. Measured concentrations of HHCB in effluent and sludge from a monitoring program of 40 WWTPs across the U.S. formed the basis for estimating environmental loadings. Based upon a Monte Carlo analysis, the probability of HHCB concentrations being below the PNEC (predicted no effect concentration) for pelagic freshwater organisms was greater than or equal to 99.87% under both mean and low flow regimes. Similarly, the probability of HHCB concentrations being less than the PNEC for freshwater sediment organisms was greater than or equal to 99.98%. Concentrations of HHCB in sludge amended soils were estimated for single and repeated annual sludge applications with tilling of the sludge into the soil, surface application without tilling and a combination reflecting current practice. The probability of soil HHCB concentrations being below the PNEC for soil organisms after repeated sludge applications was 94.35% with current sludge practice. Probabilistic estimates of HHCB exposures in surface waters, sediments and sludge amended soils are consistent with the published values for the U.S. In addition, the results of these analyses indicate that HHCB entering the environment in WWTP effluent and sludge poses negligible risk to aquatic and terrestrial organisms in nearly all exposure scenarios. PMID:24802072

  1. Monte Carlo calculation of dose rate conversion factors for external exposure to photon emitters in soil.

    PubMed

    Clouvas, A; Xanthos, S; Antonopoulos-Domis, M; Silva, J

    2000-03-01

    The dose rate conversion factors D(CF) (absorbed dose rate in air per unit activity per unit of soil mass, nGy h(-1) per Bq kg(-1)) are calculated 1 m above ground for photon emitters of natural radionuclides uniformly distributed in the soil. Three Monte Carlo codes are used: 1) The MCNP code of Los Alamos; 2) The GEANT code of CERN; and 3) a Monte Carlo code developed in the Nuclear Technology Laboratory of the Aristotle University of Thessaloniki. The accuracy of the Monte Carlo results is tested by the comparison of the unscattered flux obtained by the three Monte Carlo codes with an independent straightforward calculation. All codes and particularly the MCNP calculate accurately the absorbed dose rate in air due to the unscattered radiation. For the total radiation (unscattered plus scattered) the D(CF) values calculated from the three codes are in very good agreement between them. The comparison between these results and the results deduced previously by other authors indicates a good agreement (less than 15% of difference) for photon energies above 1,500 keV. Antithetically, the agreement is not as good (difference of 20-30%) for the low energy photons. PMID:10688452

  2. COMPARISON OF THE BIOAVAILABILITY OF ELEMENTAL WASTE LADEN SOILS USING IN VIVO AND IN VITRO ANALYTICAL METHODOLOGY, AND REFINEMENT OF EXPOSURE/DOSE MODELS

    EPA Science Inventory

    Hazardous waste contamination problems are prevalent in soils at DOE sites. Currently, they can be prioritized by estimating the human exposure and health risks from potential human contact with contaminants based upon the total extractable levels of contaminants of concern prese...

  3. Ongoing soil arsenic exposure of children living in an historical gold mining area in regional Victoria, Australia: Identifying risk factors associated with uptake

    NASA Astrophysics Data System (ADS)

    Martin, Rachael; Dowling, Kim; Pearce, Dora; Bennett, John; Stopic, Attila

    2013-11-01

    Elevated levels of arsenic have been observed in some mine wastes and soils around historical gold mining areas in regional Victoria, Australia. Arsenic uptake from soil by children living in these areas has been demonstrated using toenail arsenic concentration as a biomarker, with evidence of some systemic absorption associated with periodic exposures. We conducted a follow-up study to ascertain if toenail arsenic concentrations, and risk factors for exposure, had changed over a five year period in an historical gold mining region in western regional Victoria, Australia. Residential soil samples (N = 14) and toenail clippings (N = 24) were analyzed for total arsenic using instrumental neutron activation analysis, including 19 toenail clippings samples that were obtained from the same study cohort in 2006. Toenail arsenic concentrations in 2011 (geometric mean, 0.171 μg/g; range, 0.030-0.540 μg/g) were significantly lower than those in 2006 (geometric mean, 0.464 μg/g; range, 0.150-2.10 μg/g; p < 0.001). However, toenail arsenic concentrations were again correlated with soil arsenic levels (Spearman's rho = 0.630; p = 0.001). Spending time outdoors more often and for longer periods correlates with increased arsenic uptake (p < 0.05). Mining-influenced residential soils represent a long-term continuing source for potential arsenic exposure for children living in this historical mining region.

  4. Dewetting of thin films on flexible substrates via direct-write laser exposure

    NASA Astrophysics Data System (ADS)

    Ferrer, Anthony Jesus

    Microelectromechanical systems (MEMS) have enabled a wide variety of technologies both in the consumer space and in industrial/research areas. At the market level, such devices advance by the invention and innovation of production techniques. Additionally, there has been increased demand for flexible versions of such MEMS devices. Thin film patterning, represents a key technology for the realization of such flexible electronics. Patterns and methods that can be directly written into the thin film allow for design modification on the fly with the need for harsh chemicals and long etching steps. Laser-induced dewetting has the potential to create patterns in thin films at both the microscopic and nanoscopic level without wasting deposited material. This thesis presents the first demonstration of high-speed direct-write patterning of metallic thin films that uses a laser-induced dewetting phenomenon to prevent material loss. The ability to build film material with this technique is explored using various scanning geometries. Finally, demonstrations of direct-write dewetting of a variety of thin films will be presented with special consideration for high melting point metals deposited upon polymer substrates.

  5. Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure

    PubMed Central

    Kozawa, Kathleen H.; Winer, Arthur M.; Fruin, Scott A.

    2013-01-01

    High ambient ultrafine particle (UFP) concentrations may play an important role in the adverse health effects associated with living near busy roadways. However, UFP size distributions change rapidly as vehicle emissions dilute and age. These size changes can influence UFP lung deposition rates and dose because deposition in the respiratory system is a strong function of particle size. Few studies to date have measured and characterized changes in near-road UFP size distributions in real-time, thus missing transient variations in size distribution due to short-term fluctuations in wind speed, direction, or particle dynamics. In this study we measured important wind direction effects on near-freeway UFP size distributions and gradients using a mobile platform with 5-s time resolution. Compared to more commonly measured perpendicular (downwind) conditions, parallel wind conditions appeared to promote formation of broader and larger size distributions of roughly one-half the particle concentration. Particles during more parallel wind conditions also changed less in size with downwind distance and the fraction of lung-deposited particle number was calculated to be 15% lower than for downwind conditions, giving a combined decrease of about 60%. In addition, a multivariate analysis of several variables found meteorology, particularly wind direction and temperature, to be important in predicting UFP concentrations within 150 m of a freeway (R2 = 0.46, p = 0.014). PMID:24415904

  6. [Criteria for the determination of chronic exposure to hazardous substances via soil ingestion].

    PubMed

    Konietzka, R; Dieter, H H

    1994-01-01

    Legally recoverable protection of human health against pollutant effects must have for the enforcement in practice a technically comprehensible toxicological basis, i.e., a coherence or connection between the toxicological and legal definition of a dangerous situation must be found. For this purpose toxicological and socially accepted reference points in the unit "mg of pollutant amount absorbed per kg of weight per day" (mg/[kg of weight x d]) may be used to assess a danger in the sense a sufficient probability a damage to human health exists after exposure to certain pollutant concentrations. Based on the plausible toxicological assumption that above this reference point in case of an undisturbed course of action and by giving consideration to all exposure pathways a threshold of harmlessness including all groups of the population would be exceeded, criteria both for non-carcinogenic and carcinogenic substances or for substances suspected to cause cancer are being developed. These criteria allow to determine from which point the existence of a danger would be assessable as "sufficiently probable", and hence the required coherence between legal and toxicological view to be established. PMID:8148583

  7. Human exposure to trace elements through the skin by direct contact with clothing: Risk assessment.

    PubMed

    Rovira, Joaquim; Nadal, Martí; Schuhmacher, Marta; Domingo, José L

    2015-07-01

    Metals in textile products and clothing are used for many purposes, such as metal complex dyes, pigments, mordant, catalyst in synthetic fabrics manufacture, synergists of flame retardants, antimicrobials, or as water repellents and odour-preventive agents. When present in textile materials, heavy metals may mean a potential danger to human health. In the present study, the concentrations of a number of elements (Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Tl, V, and Zn) were determined in skin-contact clothes. Analysed clothes were made of different materials, colours, and brands. Interestingly, we found high levels of Cr in polyamide dark clothes (605 mg/kg), high Sb concentrations in polyester clothes (141 mg/kg), and great Cu levels in some green cotton fabrics (around 280 mg/kg). Dermal contact exposure and human health risks for adult males, adult females, and for <1-year-old children were assessed. Non-carcinogenic and carcinogenic risks were below safe (HQ<1) and acceptable (<10(-6)) limits, respectively, according to international standards. However, for Sb, non-carcinogenic risk was above 10% of the safety limit (HQ>0.1) for dermal contact with clothes. PMID:25889781

  8. Percutaneous absorption from soil.

    PubMed

    Andersen, Rosa Marie; Coman, Garrett; Blickenstaff, Nicholas R; Maibach, Howard I

    2014-01-01

    Abstract Some natural sites, as a result of contaminants emitted into the air and subsequently deposited in soil or accidental industrial release, have high levels of organic and non-organic chemicals in soil. In occupational and recreation settings, these could be potential sources of percutaneous exposure to humans. When investigating percutaneous absorption from soil - in vitro or vivo - soil load, particle size, layering, soil "age" time, along with the methods of performing the experiment and analyzing the results must be taken into consideration. Skin absorption from soil is generally reduced compared with uptake from water/acetone. However, the absorption of some compounds, e.g., pentachlorophenol, chlorodane and PCB 1254, are similar. Lipophilic compounds like dichlorodiphenyltrichloroethane, benzo[A]pyrene, and metals have the tendency to form reservoirs in skin. Thus, one should take caution in interpreting results directly from in vitro studies for risk assessment; in vivo validations are often required for the most relevant risk assessment. PMID:25205703

  9. Off-Site Radiation Exposure Review Project: Phase 2 soils program

    SciTech Connect

    McArthur, R.D.; Miller, F.L. Jr.

    1989-12-01

    To help estimate population doses of radiation from fallout originating at the Nevada Test Site, soil samples were collected throughout the western United States. Each sample was prepared by drying and ball-milling, then analyzed by gamma-spectrometry to determine the amount of {sup 137}Cs it contained. Most samples were also analyzed by chemical separation and alpha-spectrometry to determine {sup 239 + 240}Pu and by isotope mass spectroscopy to determine the ratios of {sup 240}Pu to {sup 239}Pu and {sup 241}Pu to {sup 239}Pu. The total inventories of cesium and plutonium at 171 sites were computed from the results. This report describes the sample collection, processing, and analysis, presents the analytical results, and assesses the quality of the data. 10 refs., 9 figs., 12 tabs.

  10. Hybrid lithography: combining UV-exposure and two photon direct laser writing.

    PubMed

    Eschenbaum, Carsten; Großmann, Daniel; Dopf, Katja; Kettlitz, Siegfried; Bocksrocker, Tobias; Valouch, Sebastian; Lemmer, Uli

    2013-12-01

    We demonstrate a method for the combination of UV-lithography and direct laser writing using two-photon polymerization (2PP-DLW). First a dye doped photoresist is used for UV-lithography. Adding an undoped photoresist on top of the developed structures enables three-dimensional alignment of the 2PP-DLW structures by detecting the spatially varying fluorescence of the two photoresists. Using this approach we show three dimensional alignment by adding 3D structures made by 2PP-DLW to a previously UV-exposed structure. Furthermore, a fluidic system with an integrated total internal reflection mirror to observe particles in a microfluidic channel is demonstrated. PMID:24514543

  11. Development and validation of a citrate synthase directed quantitative PCR marker for soil bacterial communities

    SciTech Connect

    Castro Gonzalez, Hector F; Classen, Aimee T; Austin, Emily E; Crawford, Kerri M; Schadt, Christopher Warren

    2012-01-01

    Molecular innovations in microbial ecology are allowing scientists to correlate microbial community characteristics to a variety of ecosystem functions. However, to date the majority of soil microbial ecology studies target phylogenetic rRNA markers, while a smaller number target functional markers linked to soil processes. We validated a new primer set targeting citrate synthase (gtlA), a central enzyme in the citric acid cycle linked to aerobic respiration. Primers for a 225 bp fragment suitable for qPCR were tested for specificity and assay performance verified on multiple soils. Clone libraries of the PCR-amplified gtlA gene exhibited high diversity and recovered most major groups identified in a previous 16S rRNA gene study. Comparisons among bacterial communities based on gtlA sequencing using UniFrac revealed differences among the experimental soils studied. Conditions for gtlA qPCR were optimized and calibration curves were highly linear (R2 > 0.99) over six orders of magnitude (4.56 10^5 to 4.56 10^11 copies), with high amplification efficiencies (>1.7). We examined the performance of the gtlA qPCR across a variety of soils and ecosystems, spanning forests, old fields and agricultural areas. We were able to amplify gtlA genes in all tested soils, and detected differences in gtlA abundance within and among environments. These results indicate that a fully developed gtlA-targeted qPCR approach may have potential to link microbial community characteristics with changes in soil respiration.

  12. Direct nitrous oxide (N2O) fluxes from soils under different land use in Brazil—a critical review

    NASA Astrophysics Data System (ADS)

    Meurer, Katharina H. E.; Franko, Uwe; Stange, Claus F.; Dalla Rosa, Jaqueline; Madari, Beata E.; Jungkunst, Hermann F.

    2016-02-01

    Brazil typifies the land use changes happening in South America, where natural vegetation is continuously converted into agriculturally used lands, such as cattle pastures and croplands. Such changes in land use are always associated with changes in the soil nutrient cycles and result in altered greenhouse gas fluxes from the soil to the atmosphere. In this study, we analyzed literature values to extract patterns of direct nitrous oxide (N2O) emissions from soils of different ecosystems in Brazil. Fluxes from natural ecosystems exhibited a wide range: whereas median annual flux rates were highest in Amazonian and Atlantic rainforests (2.42 and 0.88 kg N ha-1), emissions from cerrado soils were close to zero. The decrease in emissions from pastures with increasing time after conversion was associated with pasture degradation. We found comparatively low N2O-N fluxes from croplands (-0.07 to 4.26 kg N ha-1 yr-1 , median 0.80 kg N ha-1 yr-1) and a low response to N fertilization. Contrary to the assumptions, soil parameters, such as pH, Corg, and clay content emerged as poor predictors for N2O fluxes. This could be a result of the formation of micro-aggregates, which strongly affect the hydraulic properties of the soil, and consequently define nitrification and denitrification potentials. Since data from croplands mainly derived from areas that had been under natural cerrado vegetation before, it could explain the low emissions under agriculture. Measurements must be more frequent and regionally spread in order to enable sound national estimates.

  13. Patient-directed music therapy reduces anxiety and sedation exposure in mechanically-ventilated patients: a research critique.

    PubMed

    Gullick, Janice G; Kwan, Xiu Xian

    2015-05-01

    This research appraisal, guided by the CASP Randomised Controlled Trial Checklist, critiques a randomised, controlled trial of patient-directed music therapy compared to either noise-cancelling headphones or usual care. This study recruited 373 alert, mechanically-ventilated patients across five intensive care units in the United States. The Music Assessment Tool, administered by a music therapist, facilitated music selection by participants in the intervention group. Anxiety was measured using the VAS-A scale. Sedation exposure was measured by both sedation frequency and by sedation intensity using a daily sedation intensity score. Context for the data was supported by an environmental scan form recording unit activity and by written comments from nurses about the patient's responses to the protocol. Patient-directed music therapy allowed a significant reduction in sedation frequency compared to noise-cancelling headphones and usual care participants. Patient-directed music therapy led to significantly lower anxiety and sedation intensity compared to usual care, but not compared to noise-cancelling headphones. This is a robust study with clear aims and a detailed description of research methods and follow-up. While no participants were lost to follow-up, not all were included in the analysis: 37% did not have the minimum of two anxiety assessments for comparison and 23% were not included in sedation analysis. While some participants utilised the intervention or active control for many hours-per-day, half the music therapy participants listened for 12min or less per day and half of the noise-cancelling headphone participants did not appear to use them. While the results suggest that patient-directed music therapy and noise-cancelling headphones may be useful and cost-effective interventions that lead to an overall improvement in anxiety and sedation exposure, these may appeal to a subset of ICU patients. The self-directed use of music therapy and noise

  14. Direct Detection of Soil mRNAs using Targeted Microarrays for Genes Associated with Lignin Degradation

    SciTech Connect

    Bailey, Vanessa L.; Fansler, Sarah J.; Bandyopadhyay, Somnath; Smith, Jeff L.; Waters, Katrina M.; Bolton, Harvey

    2010-07-04

    Microarrays have become established tools for describing microbial systems, however the assessment of expression profiles for environmental microbial communities still presents unique challenges. Notably, the concentration of particular transcripts are likely very dilute relative to the pool of total RNA, and PCR-based amplification strategies are vulnerable to amplification biases and the appropriate primer selection. Thus, we apply a signal amplification approach, rather than template amplification, to analyze the expression of genes encoding selected lignin-degrading enzymes in soil. Controls in the form of known amplicons and cDNA from Phanerochaete chrysosporium were included and mixed with the soil cDNA both before and after the signal amplification in order to assess the dynamic range of the microarray. We demonstrate that restored prairie soil expresses a diverse range of genes encoding lignin-degrading enzymes following incubation with lignin substrate, while farmed agricultural soil does not. The mixed additions of control cDNA with soil cDNA does interfere with detection of the low abundance transcripts, nevertheless this microarray approach consistently reports the higher-abundance transcripts which present more robust signals.

  15. Development of a direct exposure system for studying the mechanisms of central neurotoxicity caused by volatile organic compounds

    PubMed Central

    KANEMITSU, Masanari; FUETA, Yukiko; ISHIDAO, Toru; AOU, Shuji; HORI, Hajime

    2015-01-01

    Many volatile organic compounds (VOCs) used in work places are neurotoxic. However, it has been difficult to study the cellular mechanisms induced by a direct exposure to neurons because of their high volatility. The objective of this study was to establish a stable system for exposing brain slices to VOCs. With a conventional recording system for brain slices, it is not possible to keep a constant bath concentration of relatively highly volatile solvents, e.g. 1-bromopropane (1-BP). Here we report a new exposure system for VOCs that we developed in which a high concentration of oxygen is dissolved to a perfused medium applying a gas-liquid equilibrium, and in which the tubing is made of Teflon, non adsorptive material. Using our system, the bath concentration of the perfused 1-BP remained stable for at least 2 h in the slice chamber. Both 6.4 and 2.2 mM of 1-BP did not change the paired-pulse response, but fully suppressed long-term potentiation in the dentate gyrus (DG) of hippocampal slices obtained from rats, suggesting that 1-BP decreases synaptic plasticity in the DG at the concentrations tested. Our new system can be applicable for investigating the underlying mechanisms of the neurotoxicity of VOCs at the cellular level. PMID:26320726

  16. Sequential combination of imipramine and self-directed exposure in the treatment of panic disorder with agoraphobia.

    PubMed

    Mavissakalian, M

    1990-05-01

    Thirty-eight patients who had panic disorder with agoraphobia completed 8 weeks of treatment with imipramine followed by 8 weeks of treatment with imipramine combined with behavior therapy consisting of self-directed exposure. Sixty-three percent (24) of the patients responded markedly to this cost-effective combined pharmacologic and behavioral approach. Results also revealed that most of the improvement in panic occurred during the first 8 weeks of treatment when imipramine treatment alone was used, whereas improvement in severity, anxiety, depression, and phobias, in particular, continued to be significant between midtreatment and end of study. Further analysis revealed that improvement in phobic anxiety and avoidance in the first 8 weeks of treatment, rather than improvement in panic, predicted final outcome. Implications of these findings on the complex issue of differential antipanic and antiphobic effects of imipramine are briefly discussed. PMID:2335493

  17. Flow direction indicators in lithic-rich, basal ground layers in western exposures of the Miocene Peach Spring Tuff, California

    NASA Astrophysics Data System (ADS)

    Buesch, D.

    2012-12-01

    Lithic-rich, basal ground layer (BGL) deposits occur in three western exposures of the 18.7 Ma Peach Spring Tuff (PST), and structures indicate directions of transport in the pyroclastic flow. Locations include (1) Kane Wash (Newberry Mountains), (2) "West Gem" (Daggett Ridge), and (3) Alvord Mountain area. These locations are 190-225 km from the PST source in the Silver Creek Caldera, southwest Black Mountain, Arizona (Pearthree and others, 2009); however, ~50 km is from extension across the Lower Colorado River Extensional Corridor. In each location, many lithic clasts were locally derived. Lithic-rich horizons in Kane Wash exposures of the PST were described by Buesch (1991). Total thickness of valley-filling ignimbrite ranges from <1-30 m and was deposited on alluvial fan and axial stream sandstone. Thickness of 8 individual lithic-rich horizons (a type of BGL) range from 4-300 cm with lithic clasts 2-472 cm. Clast size-grading, imbrication, and elongation indicate directions of flow. Each horizon was attributed to (1) incorporation and concentration of local clasts into a boundary layer of the pyroclastic flow as it traversed topography, (2) decoupling of a lithic-rich layer from the over riding flow, (3) independent movement of a lithic-rich flow along local topography (180°±30°) with the ash-rich pyroclastic flow direction probably independent of local topography, but along the main paleovalley (245°±20°), and (4) introduction and westward deflection of lithic-rich flows into the main, valley-filling, pyroclastic flow. Multiple lithic-rich horizons indicate repeated, locally developed boundary layers from the body of the pyroclastic flow throughout the flow history. In the West Gem exposure, the PST is 5.3 m thick and was deposited on alluvial sandstone. The 60-cm thick, lithic-rich, BGL contains lithic clasts <25 cm. Poorly developed clast imbrication and elongation, and a rip-up flap from the BGL folded into the lower part of the ignimbrite, indicate

  18. A Study of the Frequency and Social Determinants of Exposure to Cancer-Related Direct-to-Consumer Advertising Among Breast, Prostate, and Colorectal Cancer Patients.

    PubMed

    Tan, Andy S L

    2015-01-01

    Cancer-related direct-to-consumer advertising (DTCA) is controversial because cancer treatment is complex and entails more risks and costs than typical treatments that are advertised for other conditions. Drawing from the Structural Influence Model of Communication, this study explores communication inequalities in DTCA exposure across social determinants among a population-based sample of 2013 patients diagnosed with breast, prostate, or colorectal cancers. Three survey items assessed patients' frequency of encountering ads concerning treatment alternatives for cancer, dealing with side effects of treatment, and doctors or hospitals offering services for cancer following their diagnosis. The analysis showed that overall exposure to DTCA in this study population was modest (median was once per week). Breast cancer patients reported significantly higher exposure to all three ad categories and overall DTCA exposure than prostate and colorectal cancer patients. Older patients consistently reported lower overall exposure to DTCA across the three cancer types. Other significant correlates included ethnicity (higher exposures among African American prostate cancer patients vs. White; lower exposures in Hispanic colorectal cancer patients vs. White) and cancer stage (higher exposures in Stage IV prostate cancer patients vs. Stages 0-II). Education level did not predict patients' DTCA exposure. The implications of these observed inequalities in DTCA exposure on cancer outcomes are discussed. PMID:25357119

  19. Outbreak of microsporidial keratoconjunctivitis with rugby sport due to soil exposure

    PubMed Central

    Kwok, A K H; Tong, J M K; Tang, B S F; Poon, R W S; Li, W W T; Yuen, K Y

    2013-01-01

    Aims To investigate a cluster of microsporidial keratoconjunctivitis in 33 eyes of 25 previously healthy paediatric and teenage individuals after a rugby match. Methods An observational case series was reported. Analysis of medical record of patients with microsporidial keratoconjunctivitis, who presented within May 2012, was performed. All patients were treated by a single ophthalmologist with a standardized topical regime, including a fluoroquinolone (moxifloxacin) and an antiseptic (Brolene or Desomedine). Five eyes received corneal scrapings. Results The mean age was 13.36 years (range 5–16). All patients have participated in a rugby match on 21–22 April 2012. The onset of symptoms ranged from 10 to 30 days post exposure. All eyes had multiple superficial coarse punctate keratitis. Four (12%) eyes presented with keratic precipitates. One (3%) eye had intraocular pressure of 27 mm Hg. Microscopic examination of corneal scrapings with modified trichrome or calcofluor white (CFW) fluorescent staining was unremarkable but subsequent PCR test was positive for the small subunit rRNA gene of Vittaforma corneae in three out of five eyes. Sequencing of the PCR product of 1150 bp showed 96–100% identity with the Indian or Singaporean strains of V. corneae. After treatment, all eyes healed without sequel. Conclusions The first outbreak of microsporidial keratoconjunctivitis in paediatric and teenage individuals with a rugby match is reported. A standardized topical regime, including a fluoroquinolone (moxifloxacin) and an antiseptic (Brolene or Desomedine), seems to be safe and effective, and requires validation in future treatment trials. PMID:23598669

  20. Evaluation of the Relationship between Current Internal 137Cs Exposure in Residents and Soil Contamination West of Chernobyl in Northern Ukraine.

    PubMed

    Kimura, Yuko; Okubo, Yuka; Hayashida, Naomi; Takahashi, Jumpei; Gutevich, Alexander; Chorniy, Sergiy; Kudo, Takashi; Takamura, Noboru

    2015-01-01

    After the Chernobyl Nuclear Power Plant accident, the residents living around the Chernobyl were revealed to have been internally exposed to 137Cs through the intake of contaminated local foods. To evaluate the current situation of internal 137Cs exposure and the relationship between the 137Cs soil contamination and internal exposure in residents, we investigated the 137Cs body burden in residents who were living in 10 selected cities from the northern part of the Zhitomir region, Ukraine, and collected soil samples from three family farms and wild forests of each city to measured 137Cs concentrations. The total number of study participants was 36,862, of which 68.9% of them were female. After 2010, the annual effective doses were less than 0.1 mSv in over 90% of the residents. The 137Cs body burden was significantly higher in autumn than other seasons (p < 0.001) and in residents living in more contaminated areas (p < 0.001). We also found a significant correlation between the proportion of residents in each city with an estimated annual exposure dose exceeding 0.1 mSv and 137Cs concentration of soil samples from family farms (r = 0.828, p = 0.003). In conclusion, more than 25 years after the Chernobyl accident, the internal exposure doses to residents living in contaminated areas of northern Ukraine is limited but still related to 137Cs soil contamination. Furthermore, the consumption of local foods is considered to be the cause of internal exposure. PMID:26402065

  1. Evaluation of the Relationship between Current Internal 137Cs Exposure in Residents and Soil Contamination West of Chernobyl in Northern Ukraine

    PubMed Central

    Kimura, Yuko; Okubo, Yuka; Hayashida, Naomi; Takahashi, Jumpei; Gutevich, Alexander; Chorniy, Sergiy; Kudo, Takashi; Takamura, Noboru

    2015-01-01

    After the Chernobyl Nuclear Power Plant accident, the residents living around the Chernobyl were revealed to have been internally exposed to 137Cs through the intake of contaminated local foods. To evaluate the current situation of internal 137Cs exposure and the relationship between the 137Cs soil contamination and internal exposure in residents, we investigated the 137Cs body burden in residents who were living in 10 selected cities from the northern part of the Zhitomir region, Ukraine, and collected soil samples from three family farms and wild forests of each city to measured 137Cs concentrations. The total number of study participants was 36,862, of which 68.9% of them were female. After 2010, the annual effective doses were less than 0.1 mSv in over 90% of the residents. The 137Cs body burden was significantly higher in autumn than other seasons (p < 0.001) and in residents living in more contaminated areas (p < 0.001). We also found a significant correlation between the proportion of residents in each city with an estimated annual exposure dose exceeding 0.1 mSv and 137Cs concentration of soil samples from family farms (r = 0.828, p = 0.003). In conclusion, more than 25 years after the Chernobyl accident, the internal exposure doses to residents living in contaminated areas of northern Ukraine is limited but still related to 137Cs soil contamination. Furthermore, the consumption of local foods is considered to be the cause of internal exposure. PMID:26402065

  2. Direct Polymerase Chain Reaction-Based Detection of Cercospora Beticola in Field Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cercospora beticola, the causal agent of Cercospora leaf spot of sugar beet, survives as pseudostromata in infected beet leaf residues in the soil. Under optimal conditions, overwintering propagules germinate and produce conidia that are dispersed as primary inoculum to initiate infection in sugar b...

  3. Soil heat flux variability influenced by row direction in irrigated cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In applications of micrometeorological techniques for surface energy balance estimation, most often the least attention and effort has been devoted to determining the area-average soil heat flux (G). Although spatial and temporal variability in G under sparse/clumped vegetation conditions is signif...

  4. Soil respiration, root biomass, and root turnover following long-term exposure of northern forests to elevated atmospheric CO2 and tropospheric O3.

    PubMed

    Pregitzer, Kurt S; Burton, Andrew J; King, John S; Zak, Donald R

    2008-01-01

    The Rhinelander free-air CO(2) enrichment (FACE) experiment is designed to understand ecosystem response to elevated atmospheric carbon dioxide (+CO(2)) and elevated tropospheric ozone (+O(3)). The objectives of this study were: to understand how soil respiration responded to the experimental treatments; to determine whether fine-root biomass was correlated to rates of soil respiration; and to measure rates of fine-root turnover in aspen (Populus tremuloides) forests and determine whether root turnover might be driving patterns in soil respiration. Soil respiration was measured, root biomass was determined, and estimates of root production, mortality and biomass turnover were made. Soil respiration was greatest in the +CO(2) and +CO(2) +O(3) treatments across all three plant communities. Soil respiration was correlated with increases in fine-root biomass. In the aspen community, annual fine-root production and mortality (g m(-2)) were positively affected by +O(3). After 10 yr of exposure, +CO(2) +O(3)-induced increases in belowground carbon allocation suggest that the positive effects of elevated CO(2) on belowground net primary productivity (NPP) may not be offset by negative effects of O(3). For the aspen community, fine-root biomass is actually stimulated by +O(3), and especially +CO(2) +O(3). PMID:18643941

  5. Occurence of the phthalate esters in soil and street dust samples from the Novi Sad city area, Serbia, and the influence on the children's and adults' exposure.

    PubMed

    Škrbić, Biljana D; Ji, Yaqin; Đurišić-Mladenović, Nataša; Zhao, Jie

    2016-07-15

    This is the first study reporting the presence of 6 phthalic acid esters (PAEs) in 60 composite soil and street dust samples collected in the urban zone of Novi Sad, the second largest city in Serbia. The results were further used to assess children's and adults' PAEs nondietary daily intakes (DIs) through incidental soil and dust ingestion and/or dermal absorption. The study could be regarded as the important baseline for future monitoring of PAEs in the urban environments, particularly as it contributes to the rare data on PAEs occurence in the street dust. All 6 PAEs were detected in every analyzed soil and street dust samples from 0.0002mgkg(-1) to 4.82mgkg(-1), with the highest level obtained for di-(2-ethylhexyl) phthalate (DEHP), which was the most dominant PAE (70-96%). The highest total PAEs (Σ6PAEs) contents in soil (2.12mgkg(-1)) and street dust (5.45mgkg(-1)) samples were obtained for the samples from city parks. In all soil samples, Σ6PAEs exceeded the soil sustainable quality limit sets by the relevant Serbian Regulation, but were much lower than the limit requiring remediation measures. Concerning the estimated DIs, children were more susceptible to PAEs intake than adults regardless of the exposure routes. All the estimated DIs values were far below the known reference values. PMID:27039030

  6. Direct surface analysis of pesticides on soil, leaves, grass, and stainless steel by static secondary ion mass spectrometry

    SciTech Connect

    Ingram, J.C.; Groenewold, G.S.; Appelhans, A.D.; Delmore, J.E.; Olson, J.E.; Miller, D.L.

    1997-02-01

    Direct surface analyses by static secondary ion mass spectrometry (SIMS) were performed for the following pesticides adsorbed on dandelion leaves, grass, soil, and stainless steel samples: alachlor, atrazine, captan, carbofuran, chlorpyrifos, chlorosulfuron, chlorthal-dimethyl, cypermethrin, 2,4-D, diuron, glyphosate, malathion, methomyl, methyl arsonic acid, mocap, norflurazon, oxyfluorfen, paraquat, temik, and trifluralin. The purpose of this study was to evaluate static SIMS as a tool for pesticide analysis, principally for use in screening samples for pesticides. The advantage of direct surface analysis compared with conventional pesticide analysis methods is the elimination of sample pretreatment including extraction, which streamlines the analysis substantially; total analysis time for SIMS analysis was ca. 10 min/sample. Detection of 16 of the 20 pesticides on all four substrates was achieved. Of the remaining four pesticides, only one (trifluralin) was not detected on any of the samples. The minimum detectable quantity was determined for paraquat on soil in order to evaluate the efficacy of using SIMS as a screening tool. Paraquat was detected at 3 pg/mm{sup 2} (c.a. 0.005 monolayers). The results of these studies suggest that SIMS is capable of direct surface detection of a range of pesticides, with low volatility, polar pesticides being the most easily detected. 25 refs., 2 figs., 2 tabs.

  7. Human Exposure Assessment: Development of methods to assess the bioaccessibility of organic contaminants sorbed to soils and house dusts

    EPA Science Inventory

    Research task- Are physicochemical properties of soil and house dust predictive of the bioaccessibility of sorbed organic compoundsGoalIdentify dust and soil characteristics that influence the bioaccessibility of organic compounds and provide chemical specific data on the fractio...

  8. A soil water balance shift is driving directional change in northern forests

    NASA Astrophysics Data System (ADS)

    Erickson, A. M.; Nitschke, C.; Coops, N. C.; Cumming, S.; Stenhouse, G.

    2014-12-01

    Human activities are driving climatic warming and more frequent extreme weather, persistent throughout the recent warming hiatus. The effects of these changes on vegetation phenology remains poorly understood. Forest phenology studies typically focus on the length of the growing season and related changes in carbon uptake. Changes to tree regeneration remain uncertain, yet carry multiple climate feedback pathways. Dominant tree species drive forest biogeochemistry, with species varying in nutrient cycling, soil biota, biogenic volatile organic compound emissions, and productivity under drought, while drought conditions are likely to increase in severity. Regeneration processes underlie forest dynamics, the largest source of biosphere model uncertainty. We applied a process-based tree germination and establishment model to a study area in western Canada in order to estimate the effects of 20th and 21stcentury climatic change on regeneration in northern forests. We parameterized the model for 21 major tree species using biophysical parameters derived from the literature. We classified daily weather station and soils data for fourteen biogeoclimatic regions within the study area for three historical 30-year periods and the most recent decade: 1923-1952, 1953-1982, 1983-2012, and 2003-2012. We simulated the effects of changing temperature and precipitation conditions on germination and establishment processes for 21 tree species, fourteen regions, and four time periods. We found that regeneration conditions diminished across the 1923 to 2012 period, driven by soil water limitations. While regeneration conditions improved during the recent warming hiatus, a downward trend persists at a multi-decadal scale. In contrast to studies indicating regenerational improvements in higher latitudes and elevations, with disequilibrium in lowland forests due to a higher velocity of climatic change, we found that a soil water balance shift drove species downhill, supporting a recent

  9. Field controlled experiments on the physiological responses of maize (Zea mays L.) leaves to low-level air and soil mercury exposures.

    PubMed

    Niu, Zhenchuan; Zhang, Xiaoshan; Wang, Sen; Zeng, Ming; Wang, Zhangwei; Zhang, Yi; Ci, Zhijia

    2014-01-01

    Thousands of tons of mercury (Hg) are released from anthropogenic and natural sources to the atmosphere in a gaseous elemental form per year, yet little is known regarding the influence of airborne Hg on the physiological activities of plant leaves. In the present study, the effects of low-level air and soil Hg exposures on the gas exchange parameters of maize (Zea mays L.) leaves and their accumulation of Hg, proline, and malondialdehyde (MDA) were examined via field open-top chamber and Hg-enriched soil experiments, respectively. Low-level air Hg exposures (<50 ng m(-3)) had little effects on the gas exchange parameters of maize leaves during most of the daytime (p > 0.05). However, both the net photosynthesis rate and carboxylation efficiency of maize leaves exposed to 50 ng m(-3) air Hg were significantly lower than those exposed to 2 ng m(-3) air Hg in late morning (p < 0.05). Additionally, the Hg, proline, and MDA concentrations in maize leaves exposed to 20 and 50 ng m(-3) air Hg were significantly higher than those exposed to 2 ng m(-3) air Hg (p < 0.05). These results indicated that the increase in airborne Hg potentially damaged functional photosynthetic apparatus in plant leaves, inducing free proline accumulation and membrane lipid peroxidation. Due to minor translocation of soil Hg to the leaves, low-level soil Hg exposures (<1,000 ng g(-1)) had no significant influences on the gas exchange parameters, or the Hg, proline, and MDA concentrations in maize leaves (p > 0.05). Compared to soil Hg, airborne Hg easily caused physiological stress to plant leaves. The effects of increasing atmospheric Hg concentration on plant physiology should be of concern. PMID:23943002

  10. Estimated soil ingestion rates for use in risk assessment

    SciTech Connect

    LaGoy, P.K.

    1987-09-01

    Assessing the risks to human health posed by contaminants present in soil requires an estimate of likely soil ingestion rates. In the past, direct measurements of soil ingestion were not available and risk assessors were forced to estimate soil ingestion rates based on observations of mouthing behavior and measurements of soil on hands. Recently, empirical data on soil ingestion rates have become available from two sources. Although preliminary, these data can be used to derive better estimates of soil ingestion rates for use in risk assessments. Estimates of average soil ingestion rates derived in this paper range from 25 to 100 mg/day, depending on the age of the individual at risk. Maximum soil ingestion rates that are unlikely to underestimate exposure range from 100 to 500 mg. A value of 5000 mg/day is considered a reasonable estimate of a maximum single-day exposure for a child with habitual pica. 12 references.

  11. The impacts of trail infrastructure on vegetation and soils: Current literature and future directions.

    PubMed

    Ballantyne, Mark; Pickering, Catherine Marina

    2015-12-01

    Reflecting the popularity of nature-based activities such as hiking and mountain biking, there are thousands of kilometres of recreational trails worldwide traversing a range of natural areas. These trails have environmental impacts on soils and vegetation, but where has there been research, what impacts have been found and how were they measured? Using a systematic quantitative literature review methodology, we assessed the impacts of trails on vegetation and soils, highlighting what is known, but also key knowledge gaps. Of the 59 original research papers identified on this topic that have been published in English language peer-reviewed academic journals, most were for research conducted in protected areas (71%), with few from developing countries (17%) or threatened ecosystems (14%). The research is concentrated in a few habitats and biodiversity hotspots, mainly temperate woodland, alpine grassland and Mediterranean habitats, often in the USA (32%) or Australia (20%). Most examined formal trails, with just 15% examining informal trails and 11% assessing both types. Nearly all papers report the results of observational surveys (90%), collecting quantitative data (66%) with 24% using geographic information systems. There was an emphasis on assessing trail impacts at a local scale, either on the trail itself and/or over short gradients away from the trail edge. Many assessed changes in composition and to some degree, structure, of vegetation and soils with the most common impacts documented including reduced vegetation cover, changes in plant species composition, trail widening, soil loss and soil compaction. There were 14 papers assessing how these local impacts can accumulate at the landscape scale. Few papers assessed differences in impacts among trails (7 papers), changes in impacts over time (4), species-specific responses (3) and only one assessed effects on plant community functioning. This review provides evidence that there are key research gaps

  12. Apollo 11 and 16 Soil Bi-directional Solar Reflectance Measurements, Models and LRO Diviner Observations

    NASA Astrophysics Data System (ADS)

    Foote, E. J.; Paige, D. A.; Shepard, M. K.; Johnson, J. R.; Biggar, S. F.; Greenhagen, B. T.; Allen, C.

    2010-12-01

    We have compared laboratory solar reflectance measurements of Apollo 11 and 16 soil samples to Lunar Reconnaissance Orbiter (LRO) Diviner orbital albedo measurements at the Apollo landing sites. The soil samples are two representative end member samples from the moon, low albedo lunar maria (sample 10084) and high albedo lunar highlands (sample 68810). Bidirectional reflectance distribution function (BRDF) measurements of the soil samples were conducted at Bloomsburg University (BUG) and at the University of Arizona [1,2]. We collected two different types of BUG datasets: a standard set of BRDF measurements at incidence angles of 0-60°, emission angles of 0-80°, and phase angles of 3-140°, and a high-incidence angle set of measurements along and perpendicular to the principal plane at incidence angles of 0-75° and phase angles of 3-155°. The BUG measurements generated a total of 765 data points in four different filters 450, 550, 750 and 950 nm. The Blacklab measurements were acquired at incidence angles of 60-88°, emission angles 60-82°, and phase angles of 17-93° at wavelengths of 455, 554, 699, 949nm. The BUG data were fit to two BRDF models: Hapke’s model [3] as described by Johnson et al, 2010 [4], and a simplified empirical function. The fact that both approaches can satisfactorily fit the BUG data is not unexpected, given the similarities between the functions and their input parameters, and the fact that the BRDF for dark lunar soil is dominated by the single scattering phase functions of the individual soil particles. To compare our lunar sample measurements with LRO Diviner data [5], we selected all daytime observations acquired during the first year of operation within 3 km square boxes centered at the landing sites. We compared Diviner Channel 1 (0.3 - 3 µm) Lambert albedos with model calculated Lambert albedos of the lunar samples at the same photometric angles. In general, we found good agreement between the laboratory and Diviner

  13. The assumption of heterogeneous or homogeneous radioactive contamination in soil/sediment: does it matter in terms of the external exposure of fauna?

    PubMed

    Beaugelin-Seiller, K

    2014-12-01

    The classical approach to environmental radioprotection is based on the assumption of homogeneously contaminated media. However, in soils and sediments there may be a significant variation of radioactivity with depth. The effect of this heterogeneity was investigated by examining the external exposure of various sediment and soil organisms, and determining the resulting dose rates, assuming a realistic combination of locations and radionuclides. The results were dependent on the exposure situation, i.e., the organism, its location, and the quality and quantity of radionuclides. The dose rates ranged over three orders of magnitude. The assumption of homogeneous contamination was not consistently conservative (if associated with a level of radioactivity averaged over the full thickness of soil or sediment that was sampled). Dose assessment for screening purposes requires consideration of the highest activity concentration measured in a soil/sediment that is considered to be homogeneously contaminated. A more refined assessment (e.g., higher tier of a graded approach) should take into consideration a more realistic contamination profile, and apply different dosimetric approaches. PMID:25170547

  14. Toxic effects of the joint exposure of decabromodiphenyl ether (BDE209) and tetrabromobisphenol A (TBBPA) on soil microorganism and enzyme activity.

    PubMed

    Zhang, Wei; Chen, Lei; An, Shuai; Liu, Kou; Lin, Kuangfei; Zhao, Li

    2014-09-01

    Decabromodiphenyl ether (BDE209) and tetrabromobisphenol A (TBBPA) are the main contaminants at e-waste recycling sites, and their potential toxicological effects have received extensive attention. However, the impact on soil culturable microbial population and enzyme activity of joint exposure to the two chemicals remains almost unknown. Therefore, indoor incubation tests were performed on control and contaminated soil samples to determine the eco-toxicological response in the joint presence of BDE209 and TBBPA for the first time. The results have demonstrated some notable toxic effects due to long-term exposure to either or both contaminants. The inhibition ratios of microbial populations increased with incubation time and increasing concentrations of BDE209 or TBBPA following certain dose-response relationships and time-effect trends. The response sensitivity sequence was fungi>bacteria>actinomycete. The influence of the two chemicals on soil enzymes reached peak values on day 7, and highly significant differences (P<0.01) were observed compared to the controls. Urease was more susceptive to the two chemicals than catalase and saccharase activities. Generally, the joint toxicity of both contaminants on soil microbes, catalase or saccharase activities indicated antagonistic effects, while, as for urease activity, addition role was dominant. Such observations have provided the useful information of potential ecological effects of brominated flame retardants contamination in the environment. PMID:25195096

  15. Data Sources for Prioritizing Human Exposure to Chemicals

    EPA Science Inventory

    Humans may be exposed to thousands of chemicals through contact in the workplace, home, and via air, water, food, and soil. A major challenge is estimating chemical exposures, which requires understanding potential exposure pathways directly related to how chemicals are used. Wit...

  16. Direct incorporation of fatty acids into microbial phospholipids in soils: Position-specific labeling tells the story

    NASA Astrophysics Data System (ADS)

    Dippold, Michaela A.; Kuzyakov, Yakov

    2016-02-01

    Fatty acids have been used as plant and microbial biomarkers, and knowledge about their transformation pathways in soils and sediments is crucial for interpreting fatty acid signatures, especially because the formation, recycling and decomposition processes are concurrent. We analyzed the incorporation of free fatty acids into microbial fatty acids in soil by coupling position-specific 13C labeling with compound-specific 13C analysis. Position-specifically and uniformly 13C labeled palmitate were applied in an agricultural Luvisol. Pathways of fatty acids were traced by analyzing microbial utilization of 13C from individual molecule positions of palmitate and their incorporation into phospholipid fatty acids (PLFA). The fate of palmitate 13C in the soil was characterized by the main pathways of microbial fatty acid metabolism: Odd positions (C-1) were preferentially oxidized to CO2 in the citric acid cycle, whereas even positions (C-2) were preferentially incorporated into microbial biomass. This pattern is a result of palmitate cleavage to acetyl-CoA and its further use in the main pathways of C metabolism. We observed a direct, intact incorporation of more than 4% of the added palmitate into the PLFA of microbial cell membranes, indicating the important role of palmitate as direct precursor for microbial fatty acids. Palmitate 13C was incorporated into PLFA as intact alkyl chain, i.e. the C backbone of palmitate was not cleaved, but palmitate was incorporated either intact or modified (e.g. desaturated, elongated or branched) according to the fatty acid demand of the microbial community. These modifications of the incorporated palmitate increased with time. Future PLFA studies must therefore consider the recycling of existing plant and microbial-derived fatty acids. This study demonstrates the intact uptake and recycling of free fatty acids such as palmitate in soils, as well as the high turnover and transformation of cellular PLFA. Knowledge about the intact

  17. Chronic exposure to soil salinity in terrestrial species: Does plasticity and underlying physiology differ among specialized ground-dwelling spiders?

    PubMed

    Renault, D; Puzin, C; Foucreau, N; Bouchereau, A; Pétillon, J

    2016-07-01

    In salt marshes, the alternation of low and high tides entails rapid shifts of submersion and aerial exposure for terrestrial communities. In these intertidal environments, terrestrial species have to deal with an osmotic loss in body water content and an increase in sodium chloride concentration when salt load increases. In salt marshes, spiders represent an abundant arthropod group, whose physiological ecology in response to variations of soil salinity must be further investigated. In this study, we compared the effect of salinity on the survival and physiology of three species of Lycosidae; two salt marsh species (Arctosa fulvolineata and Pardosa purbeckensis) and one forest species (P. saltans). Spiders were individually exposed at three salinity conditions (0‰, 35‰ and 70‰) and survival, changes in body water content, hemolymph ions (Na(+), Ca(2+), Mg(2+), K(+); ICP-MS technique) and metabolites (mainly amino acids, polyols, sugars; LC and GC techniques) were assessed. The survival of the forest species P. saltans was very quickly hampered at moderate and high salinities. In this spider, variations of hemolymph ions and metabolites revealed a quick loss of physiological homeostasis and a rapid salt-induced dehydration of the specimens. Conversely, high survival durations were measured in the two salt-marsh spiders, and more particularly in A. fulvolineata. In both P. purbeckensis and A. fulvolineata, the proportion of Na(+), Ca(2+), Mg(2+), K(+) remained constant at the three experimental conditions. Accumulation of hemolymph Na(+) and amino acids (mainly glutamine and proline) demonstrated stronger osmoregulatory capacities in these salt-marsh resident spiders. To conclude, even if phylogenetically close (belonging to the same, monophyletic, family), we found different physiological capacities to cope with salt load among the three tested spider species. Nevertheless, physiological responses to salinity were highly consistent with the realized

  18. 1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil.

    PubMed

    Lankadurai, Brian P; Furdui, Vasile I; Reiner, Eric J; Simpson, André J; Simpson, Myrna J

    2013-01-01

    1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS) in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg) for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS), betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA) of contaminants is not clearly defined. PMID:24958147

  19. 1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil

    PubMed Central

    Lankadurai, Brian P.; Furdui, Vasile I.; Reiner, Eric J.; Simpson, André J.; Simpson, Myrna J.

    2013-01-01

    1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS) in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg) for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS), betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA) of contaminants is not clearly defined. PMID:24958147

  20. Does cycad aulacaspis scale (Aulacaspis yasumatsui, Hemiptera: Diaspididae) play a direct role in causing soil phytotoxicity?

    PubMed Central

    Watson, Gillian; Marler, Thomas E

    2014-01-01

    Cycad aulacaspis scale (CAS, Aulacaspis yasumatsui, Hemiptera: Diaspididae) was accidentally introduced to Guam in 2003, and has caused acute mortality of the dominant, endemic forest tree Cycas micronesica. A phytotoxic legacy in the soils beneath cycad trees killed by CAS over a period of about three years has been demonstrated. The origin of the toxicity may be large quantities of CAS-encrusted cycad leaf litter. We explore the possibility that a major contribution to this toxic legacy may come from the scale insects, not just from the plant material. PMID:25083170

  1. Assessing Children’s Dietary Pesticide Exposure: Direct Measurement of Pesticide Residues in 24-Hr Duplicate Food Samples

    PubMed Central

    Lu, Chensheng; Schenck, Frank J.; Pearson, Melanie A.; Wong, Jon W.

    2010-01-01

    Background The data presented here are a response to calls for more direct measurements of pesticide residues in foods consumed by children and provide an opportunity to compare direct measures of pesticide residues in foods representing actual consumption with those reported by the U.S. Department of Agriculture Pesticide Data Program. Objective We measured pesticide residues in 24-hr duplicate food samples collected from a group of 46 young children participating in the Children’s Pesticide Exposure Study (CPES). Methods Parents were instructed to collect 24-hr duplicate food samples of all conventional fruits, vegetables, and fruit juices equal to the quantity consumed by their children, similarly prewashed/prepared, and from the same source or batch. Individual or composite food items were analyzed for organophosphate (OP) and pyrethroid insecticide residues. Results We collected a total of 239 24-hr duplicate food samples collected from the 46 CPES children. We found 14% or 5% of those food samples contained at least one OP or pyrethroid insecticide, respectively. We measured a total of 11 OP insecticides, at levels ranging from 1 to 387 ng/g, and three pyrethroid insecticides, at levels ranging from 2 to 1,133 ng/g, in children’s food samples. We found that many of the food items consumed by the CPES children were also on the list of the most contaminated food commodities reported by the Environmental Working Group. Conclusions The frequent consumption of food commodities with episodic presence of pesticide residues that are suspected to cause developmental and neurological effects in young children supports the need for further mitigation. PMID:20639183

  2. Dioxin Exposure Blocks Lactation through a Direct Effect on Mammary Epithelial Cells Mediated by the Aryl Hydrocarbon Receptor Repressor

    PubMed Central

    Basham, Kaitlin J.; Leonard, Christopher J.; Kieffer, Collin; Shelton, Dawne N.; McDowell, Maria E.; Bhonde, Vasudev R.; Looper, Ryan E.; Welm, Bryan E.

    2015-01-01

    In mammals, lactation is a rich source of nutrients and antibodies for newborn animals. However, millions of mothers each year experience an inability to breastfeed. Exposure to several environmental toxicants, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has been strongly implicated in impaired mammary differentiation and lactation. TCDD and related polyhalogenated aromatic hydrocarbons are widespread industrial pollutants that activate the aryl hydrocarbon receptor (AHR). Despite many epidemiological and animal studies, the molecular mechanism through which AHR signaling blocks lactation remains unclear. We employed in vitro models of mammary differentiation to recapitulate lactogenesis in the presence of toxicants. We demonstrate AHR agonists directly block milk production in isolated mammary epithelial cells. Moreover, we define a novel role for the aryl hydrocarbon receptor repressor (AHRR) in mediating this response. Our mechanistic studies suggest AHRR is sufficient to block transcription of the milk gene β-casein. As TCDD is a prevalent environmental pollutant that affects women worldwide, our results have important public health implications for newborn nutrition. PMID:25265996

  3. Soil coring at multiple field environments can directly quantify variation in deep root traits to select wheat genotypes for breeding.

    PubMed

    Wasson, A P; Rebetzke, G J; Kirkegaard, J A; Christopher, J; Richards, R A; Watt, M

    2014-11-01

    We aim to incorporate deep root traits into future wheat varieties to increase access to stored soil water during grain development, which is twice as valuable for yield as water captured at younger stages. Most root phenotyping efforts have been indirect studies in the laboratory, at young plant stages, or using indirect shoot measures. Here, soil coring to 2 m depth was used across three field environments to directly phenotype deep root traits on grain development (depth, descent rate, density, length, and distribution). Shoot phenotypes at coring included canopy temperature depression, chlorophyll reflectance, and green leaf scoring, with developmental stage, biomass, and yield. Current varieties, and genotypes with breeding histories and plant architectures expected to promote deep roots, were used to maximize identification of variation due to genetics. Variation was observed for deep root traits (e.g. 111.4-178.5cm (60%) for depth; 0.09-0.22cm/°C day (144%) for descent rate) using soil coring in the field environments. There was significant variation for root traits between sites, and variation in the relative performance of genotypes between sites. However, genotypes were identified that performed consistently well or poorly at both sites. Furthermore, high-performing genotypes were statistically superior in root traits than low-performing genotypes or commercial varieties. There was a weak but significant negative correlation between green leaf score (-0.5), CTD (0.45), and rooting depth and a positive correlation for chlorophyll reflectance (0.32). Shoot phenotypes did not predict other root traits. This study suggests that field coring can directly identify variation in deep root traits to speed up selection of genotypes for breeding programmes. PMID:24963000

  4. Exposure information in environmental health research: Current opportunities and future directions for particulate matter, ozone, and toxic air pollutants

    SciTech Connect

    McKone, Thomas E.; Ryan, P. Barry; Ozkaynak, Haluk

    2007-02-01

    Understanding and quantifying outdoor and indoor sources of human exposure are essential but often not adequately addressed in health-effects studies for air pollution. Air pollution epidemiology, risk assessment, health tracking and accountability assessments are examples of health-effects studies that require but often lack adequate exposure information. Recent advances in exposure modeling along with better information on time-activity and exposure factors data provide us with unique opportunities to improve the assignment of exposures for both future and ongoing studies linking air pollution to health impacts. In September 2006, scientists from the US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health in order to identify, evaluate, and improve current approaches for linking air pollution exposures to disease. This manuscript presents the key issues, challenges and recommendations identified by the exposure working group, who used cases studies of particulate matter, ozone, and toxic air pollutant exposure to evaluate health-effects for air pollution. One of the over-arching lessons of this workshop is that obtaining better exposure information for these different health-effects studies requires both goal-setting for what is needed and mapping out the transition pathway from current capabilities to meeting these goals. Meeting our long-term goals requires definition of incremental steps that provide useful information for the interim and move us toward our long-term goals. Another over-arching theme among the three different pollutants and the different health study approaches is the need for integration among alternate exposure assessment approaches. For example, different groups may advocate exposure indicators, biomonitoring, mapping methods (GIS), modeling, environmental media

  5. An Overview of Soils and Human Health

    NASA Astrophysics Data System (ADS)

    Brevik, Eric C.

    2013-04-01

    Few people recognize the connection between soils and human health, even though soils are actually very important to health. Soils influence health through the nutrients taken up by plants and the animals that eat those plants, nutrients that are needed for adequate nutrition for growth and development. Soils can also act to harm human health in three major ways: i) toxic levels of substances or disease-causing organisms may enter the human food chain from the soil ii) humans can encounter pathogenic organisms through direct contact with the soil or inhaling dust from the soil, and iii) degraded soils produce nutrient-deficient foods leading to malnutrition. Soils have also been a major source of medicines. Therefore, soils form an integral link in the holistic view of human health. In this presentation, soils and their influence on human health are discussed from a broad perspective, including both direct influences of soils on health and indirect influences through things such as climate change, occupational exposure to soil amendments, and the role of soils in providing food security.

  6. Direct and indirect effects of atmospheric conditions and soil moisture on surface energy partitioning revealed by a prolonged drought at a temperate forest site

    SciTech Connect

    Gu, Lianhong; Meyers, T. P.; Pallardy, Stephen G.; Hanson, Paul J; Yang, Bai; Heuer, Mark; Hosman, K. P.; Riggs, Jeffery S; Sluss, Daniel Wayne; Wullschleger, Stan D

    2006-01-01

    The purpose of this paper is to examine the mechanism that controls the variation of surface energy partitioning between latent and sensible heat fluxes at a temperate deciduous forest site in central Missouri, USA. Taking advantage of multiple micrometeorological and ecophysiological measurements and a prolonged drought in the middle of the 2005 growing season at this site, we studied how soil moisture, atmospheric vapor pressure deficit (VPD), and net radiation affected surface energy partitioning. We stratified these factors to minimize potential confounding effects of correlation among them. We found that all three factors had direct effects on surface energy partitioning, but more important, all three factors also had crucial indirect effects. The direct effect of soil moisture was characterized by a rapid decrease in Bowen ratio with increasing soil moisture when the soil was dry and by insensitivity of Bowen ratio to variations in soil moisture when the soil was wet. However, the rate of decrease in Bowen ratio when the soil was dry and the level of soil moisture above which Bowen ratio became insensitive to changes in soil moisture depended on atmospheric conditions. The direct effect of increased net radiation was to increase Bowen ratio. The direct effect of VPD was very nonlinear: Increased VPD decreased Bowen ratio at low VPD but increased Bowen ratio at high VPD. The indirect effects were much more complicated. Reduced soil moisture weakened the influence of VPD but enhanced the influence of net adiation on surface energy partitioning. Soil moisture also controlled how net radiation influenced the relationship between surface energy partitioning and VPD and how VPD affected the relationship between surface energy partitioning and net radiation. Furthermore, both increased VPD and increased net radiation enhanced the sensitivity of Bowen ratio to changes in soil moisture and the effect of drought on surface energy partitioning. The direct and indirect

  7. The Effect of Long-Term Thermal Exposure on the Microstructure and Stress Rupture Property of a Directionally Solidified Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Jiang, X. W.; Wang, D.; Xie, G.; Li, H.; Lou, L. H.; Zhang, J.

    2014-09-01

    Microstructural degradation and microstructure-property relationship during long-term thermal exposure in a directionally solidified Ni-based superalloy are systematically studied. The coarsening kinetics of γ' precipitation conforms well to the LSW model during the long-term thermal exposure. The detailed time dependence of MC decomposition during the long-term thermal exposure is revealed. Grain boundary coarsening was mainly facilitated by γ' and M23C6 precipitates coarsening in GBs region, and the GB coarsening kinetics conforms well to the JMAK theory. During different stages of the thermal exposure, dominant factors for the decrease of stress-rupture lifetime vary due to the evolution of multiple microstructures (γ' coarsening, MC decomposition, and grain boundary coarsening).

  8. The Effect of Long-Term Thermal Exposure on the Microstructure and Stress Rupture Property of a Directionally Solidified Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Jiang, X. W.; Wang, D.; Xie, G.; Li, H.; Lou, L. H.; Zhang, J.

    2014-12-01

    Microstructural degradation and microstructure-property relationship during long-term thermal exposure in a directionally solidified Ni-based superalloy are systematically studied. The coarsening kinetics of γ' precipitation conforms well to the LSW model during the long-term thermal exposure. The detailed time dependence of MC decomposition during the long-term thermal exposure is revealed. Grain boundary coarsening was mainly facilitated by γ' and M23C6 precipitates coarsening in GBs region, and the GB coarsening kinetics conforms well to the JMAK theory. During different stages of the thermal exposure, dominant factors for the decrease of stress-rupture lifetime vary due to the evolution of multiple microstructures ( γ' coarsening, MC decomposition, and grain boundary coarsening).

  9. Direct determination of contact angles of model soils in comparison with wettability characterization by capillary rise

    NASA Astrophysics Data System (ADS)

    Ramírez-Flores, Juan Carlos; Bachmann, Jörg; Marmur, Abraham

    2010-03-01

    SummaryAn accurate method to determine contact angles (CA) of soils as a measure of water repellency is still missing. In the present research, we evaluated and compared different methods to determine the CA of dry soil samples. Experiments were made by using a set of porous materials (silt, sand and glass beads) with different levels of water repellency. The CAs were measured with the Capillary Rise Method ( θCRM; liquid penetration into a 3-d system), the Wilhelmy plate method ( θWPM; measurement of capillary forces acting on a plane sample) and the Sessile Drop Method ( θSDM; optical CA analysis of drop contour on a plane sample). Results were compared with the CAs calculated from capillary rise in long vertical columns ( θECR), where liquid profiles of the final capillary rise of water and ethanol, respectively, were used to derive the contact angle under the assumed equilibrium conditions. The results showed the overestimation of the CA by using the well established bi-liquid CRM technique for porous materials, in particular for material with a low degree of water repellency (CA < 40°) and for the finer textured materials. In contrast, a variant of the Wilhelmy plate method, i.e. the cosine-averaged advancing CA and receding CA ( θEWPM), as well as the Sessile Drop CA, θSDM, were close to the ones of θECR. We concluded that θEWPM and θSDM are apparent CA, but nevertheless able to predict the impact of wettability on the final capillary rise which is affected by pore topology as well as by wettability.

  10. Long-Term Exposure of Tropical Soils to Pressure Treated Lumber, Barro Colorado Island, Panama: Impacts on Soil Metal Mobility and Microbial Community Structure

    NASA Astrophysics Data System (ADS)

    Marietta, M. L.; Fowle, D. A.; Roberts, J. A.

    2008-12-01

    Pressure treated lumber (CCA) has been used in a variety of structures for over seven decades, but recent concerns have been raised about leaching of metals such as chromium (Cr) and arsenic (As) into proximal soils and water supplies. Pressure treated lumber abundance and its continued use necessitate a thorough understanding of metal release and sequestration in the subsurface. To date, no long-term, in situ study on the migration of CCA compounds from lumber has been performed. Barro Colorado Island, Panama is the site of several previous CCA studies and provides an opportunity to investigate the long-term (>70 years) effects of pressure treated lumber in oxisols, where high rainfall and warm temperatures may represent an end-member condition for the leaching and mobility of these metals. Soil samples from CCA and control sites were measured for Cr, As, Cu, Zn, and Fe abundances, microbial biomass and community structure via phospholipid fatty acid analysis, along with basic soil properties. CCA lumber samples were also characterized for their metal abundance. Lumber treated with zinc meta-arsenite displayed advanced decay with elevated As, Cu, and Zn concentrations observed in the adjacent soil. Increased soil organic matter and microbial biomass correlate to decreases in Fe and Fe-associated metals compared to the control. High As concentrations persist to <1 m of the source. Lumber treated with potassium dichromate contained high chromium concentrations and displayed little decay, however, soil concentrations of Cr, Fe, and Cu were generally less than control soils. Over these same intervals, soil organic matter and microbial biomass increased, particularly the fraction of metal reducing bacteria (MRB). We hypothesize that organic carbon loading from lumber stimulates MRB, leading to mobilization of Fe and Fe-associated metals from these oxide-rich soils. Principal component analysis of PLFA data confirms a distinction between controls and samples with

  11. Direct detection, cloning and characterization of a glucoside hydrolase from forest soil.

    PubMed

    Hua, Mei; Zhao, Shubo; Zhang, Lili; Liu, Dongbo; Xia, Hongmei; Li, Fan; Chen, Shan

    2015-06-01

    A glucoside hydrolase gene, egl01, was cloned from the soil DNA of Changbai Mountain forest by homologous PCR amplification. The deduced sequence of 517 amino acids included a catalytic domain of glycoside hydrolase family 5 and was homologous to a putative cellulase from Bacillus licheniformis. The recombinant enzyme, Egl01, was maximally active at pH 5 and 50 °C and it was stable at pH 3-9, 4-50 °C, and also stable in the presence of metal ions, organic solvents, surfactants and salt. Its activity was above 120 % in 2-3 M NaCl/KCl and over 70 % was retained in 1-4 M NaCl/KCl for 6d. Egl01 hydrolyzed carboxymethyl cellulose, beechwood xylan, crop stalk, laminarin, filter paper, and avicel but not pNPG, indicating its broad substrate specificity. These properties make this recombinant enzyme a promising candidate for industrial applications. PMID:25700816

  12. Direct electrothermal atomic spectrometric determination of Ag in aqua regia extracts of soils, sediments, and sewage sludge with matrix modification.

    PubMed

    Urbanová, Iva; Husáková, Lenka; Šrámková, Jitka

    2013-04-01

    Silver is subject to significant interferences caused by high chloride concentrations in electrothermal atomic absorption spectrometry, thus its direct determination in aqua regia leaches from soils, sediments, and sludges is very difficult, especially when using instrumentation equipped with deuterium-lamp background correction (D2). In this study, the interference of the aqua regia medium was successfully eliminated using Pd-citric acid chemical modifier. This chemical modifier was found to be the most advantageous in comparison with Pd mixture with ascorbic acid, tartaric acid, or citric acid-Li based on its ability to suppress the interference originating from different chloride matrix. Palladium increases the analyte stability; citric acid serves as a reducing reagent, and furthermore, it helps to remove the interfering chlorides by forming HCl, in the drying step of the electrothermal program. In the presence of the modifier, the pyrolysis temperature can be adjusted up to 1,000 °C with no loss of the analyte. The obtained limit of detection and characteristic mass were 5 ng g(-1) and 1.7 pg, respectively. The accuracy of the method was verified by means of six different reference samples and by comparing the results of the analysis of real samples with those obtained by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer. The proposed method was applied to the Ag determination in soils, sediments, and sewage sludge samples from the Pardubice region in Czech Republic. PMID:22821329

  13. Profiling of K0 lateral stress coefficient in soils using paired directional G0 ratios

    NASA Astrophysics Data System (ADS)

    Ku, Taeseo; Mayne, Paul W.

    2013-07-01

    Using a special database compiled from directional shear wave velocity measurements at 12 well-documented sites, the geostatic stress state and stress history are evaluated from shear stiffness ratios. At each site, a benchmark profile of lateral stress coefficient (K0) was detailed using direct in-situ methods (i.e., self-boring pressuremeter, total stress cells, and/or hydraulic fracture), and/or laboratory methods (i.e., suction, consolidometer, and/or triaxial stress path testing). Also, the yield stress ratio (YSR), or more common parameter: overconsolidation ratio (OCR), was available either from series of consolidation tests on undisturbed samples procured from various depths and/or engineering geology studies, or both. Statistical expressions are derived to relate both K0 and OCR in terms of the ratio G0,HH/G0,VH as well as other factors.

  14. Efficacy of cold-pressed terpeneless Valencia oil and its primary components on inhibition of Listeria species by direct contact and exposure to vapors.

    PubMed

    Shannon, Erin M; Milillo, Sara R; Johnson, Michael G; Ricke, Steven C

    2011-09-01

    This study used disk diffusion assays to evaluate the effectiveness of cold-pressed terpeneless Valencia oil (CPTVO) and its primary components (linalool, citral, and decanal) at inhibiting Listeria via direct contact or exposure to vapors. In general, all Listeria strains tested responded similarly to CPTVO and its components. Direct contact with linalool produced zones of inhibition that were significantly smaller (P < 0.0001) than those associated with all other antimicrobials tested. Zones of inhibition for sealed plates were significantly larger (P < 0.0001) than those observed for unsealed plates, although the method for sealing the plates was insignificant. Exposure to CPTVO vapors resulted in zones of inhibition that were significantly smaller than those resulting from decanal vapors (P < 0.0001). The difference observed between the zones of inhibition produced by antimicrobial exposure via vapors or direct contact was only slightly significant (P = 0.02). Antimicrobial essential oil (EO) vapors may be an effective alternative to direct contact EOs to safely and effectively inhibit microorganisms while minimizing undesired organoleptic changes sometimes associated with EO contact. CPTVO and its primary components, decanal and citral, may have potential in the food industry as all natural, generally recognized as safe antimicrobials used in modified atmosphere packaging designed to inhibit Listeria without requiring direct contact with food products. PMID:22417555

  15. Malignant peritoneal mesothelioma following asbestos exposure.

    PubMed

    Manavoğlu, O; Orhan, B; Evrensel, T; Ozçelik, T; Yolcu, I; Kunt, E

    1996-01-01

    Clinical, epidemiological, and pathological studies have demonstrated that asbestosis plays a major role in the etiology of mesothelioma. The direct exposure of workers in industrialized countries to asbestos fibers and nonoccupational household contact elevate the risk of malignant mesothelioma. An increased risk has been found in certain geographic areas of Turkey due to the presence of asbestos deposits and the use of the material known as "white soil" as an insulation. We present a malignant mesothelioma case from rural eastern Turkey with a history of asbestos exposure from using "white soil". We review the epidemiological aspects of asbestos as they relate to mesothelioma. PMID:9216805

  16. Direction and magnitude of change in soil use for a wetland area in Chile: Puren marshes, a priority site for biodiversity conservation (stage 1).

    NASA Astrophysics Data System (ADS)

    Sepúlveda-Varas, Alejandra

    2014-05-01

    Land managers and policymakers need information about soil change caused by anthropogenic and non-anthropogenic factors to predict the effects of management on soil function, compare alternatives, and make decisions. This is particularly relevant in highly fragile ecosystems such as wetlands or humid systems. The wetlands require the presence of three key components: hydric soils, hydrophytic vegetation and wetland hydrology. Therefore, the presence of hydric soils in humid systems is essential for the existence of a wetland. In Chile, one of the geographic zones with the greatest diversity of humid systems is the coast of the Araucanía Region, which contains one of the largest and most threatened humid systems of the region, Puren Marshes, whose soils are only generically described as alluvial terraces and miscellaneous swamp. In this area, studies have reported a high intensity of anthropogenic activity, generating soil erosion, loss of wetland coverage and landscape alteration. For this first stage of a main investigation about the vulnerability of hydric soils to changes in patterns of soil use, the objective was to characterize the variables of soil use in the Puren Marshes and determinate the direction and magnitude of change in soil use in the study area for the period between 1994 and 2007 (the official reports indicate that until 1994, the total area of Puren Marshes was 1147 ha). For the analyses, were used official reports of soil use, the coverages were obtained from the project map databases "Catastro y Evaluación de los Recursos Vegetacionales Nativos de Chile" 1993 and its update for La Araucanía, Regional Government of La Araucanía 2011, DMF CONAF 2010 and IGM 2007. The map information was processed in ARCGIS 9.3.1 software under UTM coordinates, datum WGS 84 and 18 South Time extended. Was developed a multitemporal analysis by construction of transition matrix and confusion matrix. The results obtained show that for the period analysed, the

  17. Variables associated with seeking information from doctors and the internet after exposure to direct-to-consumer advertisements for prescription medications.

    PubMed

    Fogel, Joshua; Teichman, Chaim

    2014-01-01

    This study examines variables associated with seeking information from doctors, the Internet, and a combination of both doctors and Internet after exposure to direct-to-consumer advertisements. Data were analyzed from 462 college students. Younger age, women, and health insurance were associated with greater odds for doctor; women, subjective norms, intentions, and greater time since seen doctor were associated with greater odds for Internet; and African American, Hispanic, subjective norms, intentions, and health insurance were associated with greater odds for both doctor and Internet. Marketers of direct-to-consumer advertisements can use these findings for tailoring and targeting direct-to-consumer advertisements. PMID:24878404

  18. Linking Environmental Exposure with Public Health: Dichlorodiphenyltrichloroethane Extracted from Soils and Water of Recently Exposed Communities of Selected Locations in Zambia

    PubMed Central

    Sipilanyambe Munyinda, Nosiku; Michelo, Charles; Sichilongo, Kwenga

    2015-01-01

    Background. In 2000, a Zambian private mining company reintroduced the use of dichlorodiphenyltrichloroethane (DDT) to control malaria in two districts. From 2000 to 2010, DDT had been applied in homes without any studies conducted to ascertain its fate in the environment. We aimed to quantify the presence of DDT and its metabolites in the soil and water around communities where it was recently used. Methods. We collected superficial soil and water samples from drinking sources of three study areas. DDT was extracted by QuEChERS method and solid phase extraction for soils and water, respectively. Analysis was by gas chromatography-mass spectrometry. A revalidated method with limits of detection ranging from 0.034 to 0.04 ppb was used. Results. Median levels of total DDT were found at 100.4 (IQR 90.9–110) and 725.4 ng/L (IQR 540–774.5) for soils and water, respectively. No DDT above detection limits was detected in the reference area. These results are clinically significant given the persistent characteristics of DDT. Conclusion. DDT presence in these media suggests possible limitations in the environmental safeguards during IRS. Such occurrence could have potential effects on humans, especially children; hence, there is a need to further examine possible associations between this exposure and humans. PMID:26579199

  19. Direct plantlet inoculation with soil or insect-associated fungi may control cabbage root fly maggots.

    PubMed

    Razinger, Jaka; Lutz, Matthias; Schroers, Hans-Josef; Palmisano, Marilena; Wohler, Christian; Urek, Gregor; Grunder, Jürg

    2014-07-01

    A potential Delia radicum biological control strategy involving cauliflower plantlet inoculation with various fungi was investigated in a series of laboratory and glasshouse experiments. In addition to entomopathogenic fungi, fungi with a high rhizosphere competence and fungi with the ability to survive as saprotrophs in soil were tested. The following fungal species were evaluated in the experiments: Trichoderma atroviride, T. koningiopsis, T. gamsii, Beauveria bassiana, Metharhizium anisopliae, M. brunneum and Clonostachys solani. A commercial carbosulfan-based insecticide was used as a positive control. Additionally, two commercial products, one based on B. bassiana (Naturalis) and one on Bacillus thuringiensis (Delfin) were used as reference biocontrol agents. The aims were (i) to assess the pathogenicity of the selected fungal isolates to Delia radicum, (ii) to evaluate the fungal isolates' rhizosphere competence, with the emphasis on the persistence of the original inoculum on the growing roots, (iii) to assess possible endophytic plant tissue colonization, and (iv) to evaluate potential plant growth stimulating effects of the added inoculi. Significant pathogenicity of tested fungi against Delia radicum was confirmed in in vitro and glasshouse experiments. All tested fungi persisted on cauliflower rhizoplane. More importantly, the added fungi were found on thoroughly washed roots outside the original point of inoculation. This provided us with evidence that our tested fungi could be transferred via or grow with the elongating roots. In addition to colonizing the rhizoplane, some fungi were found inside the plant root or stem tissue, thus exhibiting endophytic characteristics. The importance of fungal ecology as a criterion in appropriate biological control agent selection is discussed. PMID:24907449

  20. Gaseous mercury emissions from unsterilized and sterilized soils: the effect of temperature and UV radiation.

    PubMed

    Choi, Hyun-Deok; Holsen, Thomas M

    2009-05-01

    Mercury (Hg) emissions from the soils taken from two different sites (deciduous and coniferous forests) in the Adirondacks were measured in outdoor and laboratory experiments. Some of the soil samples were irradiated to eliminate biological activity. The result from the outdoor measurements with different soils suggests the Hg emission from the soils is partly limited by fallen leaves covering the soils which helps maintain relatively high soil moisture and limits the amount of heat and solar radiation reaching the soil surface. In laboratory experiments exposure to UV-A (365 nm) had no significant effect on the Hg emissions while the Hg emissions increased dramatically during exposure to UV-B (302 nm) light suggesting UV-B directly reduced soil-associated Hg. Overall these results indicate that for these soils biotic processes have a relatively constant and smaller influence on the Hg emission from the soil than the more variable abiotic processes. PMID:19155110

  1. EFFECT OF LOW-LEVEL LEAD EXPOSURE ON PEDIATRIC NEUROBEHAVIORAL AND PHYSICAL DEVELOPMENT: CURRENT FINDINGS AND FUTURE DIRECTIONS

    EPA Science Inventory

    Studies of the relationship between lead exposure and the physical and neurobehavioral development of children constitute an important part of the scientific foundation for regulatory policies in many countries. The United States Environmental Protection Agency (U.S. EPA) recentl...

  2. Direct, delayed and residual effects of applied wastewater from olive processing on zinc and copper availability in the soil-plant system

    SciTech Connect

    Perez, J.D.; Gallardo-Lara, F.

    1993-08-01

    The authors tested the effects of wastewater from olive processing, applied alone or in combination with different mineral complements, in pots containing calcareous soil. An initial barley crop, and a subsequent ryegrass crop, yielded information on the direct and delayed effects, respectively, of the by-product on Zn and Cu assimilability in the soil-plant system. As a direct effect, the application of wastewater tended to decrease Zn assimilability, but the delayed effect showed the opposite trend, especially when the by-product was added together with N-containing mineral supplements. The direct effect generally did not significantly modify Cu assimilability, however, the delayed effect significantly enhanced Cu uptake; this effect was potentiated by the joint application of N and P. At the end of the experiment, a residual effect of the application of wastewater alone was observed, as a significant increase in extractable Cu in soil, and a nonsignificant rise in extractable Zn.

  3. Challenges and future directions to evaluating the association between prenatal exposure to endocrine disrupting chemicals and childhood obesity

    PubMed Central

    Romano, Megan E.; Savitz, David A.; Braun, Joseph M.

    2014-01-01

    Obesity is an increasing public health threat worldwide. However, there has been insufficient research addressing the obesogenic potential of prenatal exposure to environmental endocrine disrupting chemicals, largely due to complexities in the design, analysis, and interpretation of such studies. This review describes relevant biological mechanisms, addresses current challenges for investigators, presents potential strategies for overcoming them, and identifies areas where further development is required to improve future research. Special considerations for exposure assessment, outcome heterogeneity, and complex confounding structures are described. PMID:25328860

  4. Is there a relationship between earthworm energy reserves and metal availability after exposure to field-contaminated soils?

    PubMed

    Beaumelle, Léa; Lamy, Isabelle; Cheviron, Nathalie; Hedde, Mickaël

    2014-08-01

    Generic biomarkers are needed to assess environmental risks in metal polluted soils. We assessed the strength of the relationship between earthworm energy reserves and metal availability under conditions of cocktail of metals at low doses and large range of soil parameters. Aporrectodea caliginosa was exposed in laboratory to a panel of soils differing in Cd, Pb and Zn total and available (CaCl2 and EDTA-extractable) concentrations, and in soil texture, pH, CEC and organic-C. Glycogen, protein and lipid contents were recorded in exposed worms. Glycogen contents were not linked to the explaining variables considered. Variable selection identified CaCl2 extractable metals concentrations and soil texture as the main factors affecting protein and lipid contents. The results showed opposite effects of Pb and Zn, high inter-individual variability of biomarkers and weak relationships with easily extractable metals. Our results support the lack of genericity of energy reserves in earthworms exposed to field-contaminated soils. PMID:24852409

  5. Altered carbon turnover processes and microbiomes in soils under long-term extremely high CO2 exposure.

    PubMed

    Beulig, Felix; Urich, Tim; Nowak, Martin; Trumbore, Susan E; Gleixner, Gerd; Gilfillan, Gregor D; Fjelland, Kristine E; Küsel, Kirsten

    2016-01-01

    There is only limited understanding of the impact of high p(CO2) on soil biomes. We have studied a floodplain wetland where long-term emanations of temperate volcanic CO2 (mofettes) are associated with accumulation of carbon from the Earth's mantle. With an integrated approach using isotope geochemistry, soil activity measurements and multi-omics analyses, we demonstrate that high (nearly pure) CO2 concentrations have strongly affected pathways of carbon production and decomposition and therefore carbon turnover. In particular, a promotion of dark CO2 fixation significantly increased the input of geogenic carbon in the mofette when compared to a reference wetland soil exposed to normal levels of CO2. Radiocarbon analysis revealed that high quantities of mofette soil carbon originated from the assimilation of geogenic CO2 (up to 67%) via plant primary production and subsurface CO2 fixation. However, the preservation and accumulation of almost undegraded organic material appeared to be facilitated by the permanent exclusion of meso- to macroscopic eukaryotes and associated physical and/or ecological traits rather than an impaired biochemical potential for soil organic matter decomposition. Our study shows how CO2-induced changes in diversity and functions of the soil community can foster an unusual biogeochemical profile. PMID:27571979

  6. The Biotoxicity of Mars Soils

    NASA Technical Reports Server (NTRS)

    Kerney, Krystal

    2010-01-01

    Recent evidence from the Opportunity and Spirit rovers suggests that the soils on Mars might be very high in biotoxic materials induding sulfate salts, chlorides, and acidifying agents. Yet, very little is known about how the chemistries of Mars soils might affect the survival and growth of terrestrial microorganisms. The primary objectives of the proposed research will be to: (1) prepare and characterize Mars analog soils amended with potential biotoxic levels of sulfates, chlorides, and acidifying minerals; (2) use the stimulants to conduct a series of toxicology assays to determine if terrestrial microorganisms from spacecraft or extreme environments can survive direct exposure to the biotoxic soils, and (3) mix soils from extreme environments on Earth into Mars analog soils to determine if terrestrial microorganisms can grow and replicate under Martian conditions. The Mars analog soils will be thoroughly characterized by a wide diversity of soil chemistry assays to determine the exact nature of the soluble biotoxic components following hydration. The microbial experiments will be designed to test the effects of Mars stimulants on microbial survival, growth and replication during direct challenge experiments. Toxicology experiments will be designed to mimic terrestrial microbes coming into contact with biotoxic soils with and without liquid water. Results are expected to help" ... characterize the limits of life in ... planetary environments ... " and may help constrain the search for life on Mars.

  7. Contribution of Direct and Indirect Exposure to Human Serum Concentrations of Perfluorooctanoic Acid in an Occupationally Exposed Group of Ski Waxers.

    PubMed

    Gomis, Melissa I; Vestergren, Robin; Nilsson, Helena; Cousins, Ian T

    2016-07-01

    The contribution of direct (i.e., uptake of perfluorooctanoic acid (PFOA) itself) and indirect (i.e., uptake of 8:2 fluorotelomer alcohol (FTOH) and metabolism to PFOA) exposure to PFOA serum concentrations was investigated using a dynamic one-compartment pharmacokinetic (PK) model. The PK model was applied to six occupationally exposed ski waxers for whom direct and indirect exposures via inhalation were characterized using multiple measurements with personal air sampling devices. The model was able to predict the diverging individual temporal trends of PFOA in serum with correlation coefficients of 0.82-0.94. For the four technicians with high initial concentrations of PFOA in serum (250-1050 ng/mL), the ongoing occupational exposure (both direct and indirect) was of minor importance and net depuration of PFOA was observed throughout the ski season. An estimated average intrinsic elimination half-life of 2.4 years (1.8-3.1 years accounting for variation between technicians and model uncertainty) was derived for these technicians. The remaining two technicians, who had much lower initial serum concentrations (10-17 ng/mL), were strongly influenced by exposure during the ski season with indirect exposure contributing to 45% of PFOA serum concentrations. On the basis of these model simulations, an average metabolism yield of 0.003 (molar concentration basis; uncertainty range of 0.0006-0.01) was derived for transformation of 8:2 FTOH to PFOA. An uncertainty analysis was performed, and it was determined that the input parameters quantifying the intake of PFOA were mainly responsible for the uncertainty of the metabolism yield and the initial concentration of PFOA in serum was mainly contributing to the uncertainty of estimated serum half-lives. PMID:27304840

  8. Direct Exposure to Ethanol Disrupts Junctional Cell-Cell Contact and Hippo-YAP Signaling in HL-1 Murine Atrial Cardiomyocytes

    PubMed Central

    Noritake, Kanako; Aki, Toshihiko; Funakoshi, Takeshi; Unuma, Kana; Uemura, Koichi

    2015-01-01

    Direct exposure of cardiomyocytes to ethanol causes cardiac damage such as cardiac arrythmias and apoptotic cell death. Cardiomyocytes are connected to each other through intercalated disks (ID), which are composed of a gap junction (GJ), adherens junction, and desmosome. Changes in the content as well as the subcellular localization of connexin43 (Cx43), the main component of the cardiac GJ, are reportedly involved in cardiac arrythmias and subsequent damage. Recently, the hippo-YAP signaling pathway, which links cellular physical status to cell proliferation, differentiation, and apoptosis, has been implicated in cardiac homeostasis under physiological as well as pathological conditions. This study was conducted to explore the possible involvement of junctional intercellular communication, mechanotransduction through cytoskeletal organization, and the hippo-YAP pathway in cardiac damage caused by direct exposure to ethanol. HL-1 murine atrial cardiac cells were used since these cells retain cardiac phenotypes through ID formation and subsequent synchronous contraction. Cells were exposed to 0.5–2% ethanol; significant apoptotic cell death was observed after exposure to 2% ethanol for 48 hours. A decrease in Cx43 levels was already observed after 3 hours exposure to 2% ethanol, suggesting a rapid degradation of this protein. Upon exposure to ethanol, Cx43 translocated into lysosomes. Cellular cytoskeletal organization was also dysregulated by ethanol, as demonstrated by the disruption of myofibrils and intermediate filaments. Coinciding with the loss of cell-cell adherence, decreased phosphorylation of YAP, a hippo pathway effector, was also observed in ethanol-treated cells. Taken together, the results provide evidence that cells exposed directly to ethanol show 1) impaired cell-cell adherence/communication, 2) decreased cellular mechanotransduction by the cytoskeleton, and 3) a suppressed hippo-YAP pathway. Suppression of hippo-YAP pathway signaling should be

  9. Highly Sensitive Direct Detection and Quantification of Burkholderia pseudomallei Bacteria in Environmental Soil Samples by Using Real-Time PCR ▿ †

    PubMed Central

    Trung, Trinh Thanh; Hetzer, Adrian; Göhler, André; Topfstedt, Eylin; Wuthiekanun, Vanaporn; Limmathurotsakul, Direk; Peacock, Sharon J.; Steinmetz, Ivo

    2011-01-01

    The soil bacterium and potential biothreat agent Burkholderia pseudomallei causes the infectious disease melioidosis, which is naturally acquired through environmental contact with the bacterium. Environmental detection of B. pseudomallei represents the basis for the development of a geographical risk map for humans and livestock. The aim of the present study was to develop a highly sensitive, culture-independent, DNA-based method that allows direct quantification of B. pseudomallei from soil. We established a protocol for B. pseudomallei soil DNA isolation, purification, and quantification by quantitative PCR (qPCR) targeting a type three secretion system 1 single-copy gene. This assay was validated using 40 soil samples from Northeast Thailand that underwent parallel bacteriological culture. All 26 samples that were B. pseudomallei positive by direct culture were B. pseudomallei qPCR positive, with a median of 1.84 × 104 genome equivalents (range, 3.65 × 102 to 7.85 × 105) per gram of soil, assuming complete recovery of DNA. This was 10.6-fold (geometric mean; range, 1.1- to 151.3-fold) higher than the bacterial count defined by direct culture. Moreover, the qPCR detected B. pseudomallei in seven samples (median, 36.9 genome equivalents per g of soil; range, 9.4 to 47.3) which were negative by direct culture. These seven positive results were reproduced using a nested PCR targeting a second, independent B. pseudomallei-specific sequence. Two samples were direct culture and qPCR negative but nested PCR positive. Five samples were negative by both PCR methods and culture. In conclusion, our PCR-based system provides a highly specific and sensitive tool for the quantitative environmental surveillance of B. pseudomallei. PMID:21803915

  10. A High Diversity in Chitinolytic and Chitosanolytic Species and Enzymes and Their Oligomeric Products Exist in Soil with a History of Chitin and Chitosan Exposure

    PubMed Central

    Nampally, Malathi; Rajulu, M. B. Govinda; Gillet, Dominique; Suryanarayanan, T. S.; Moerschbacher, Bruno B.

    2015-01-01

    Chitin is one of the most abundant biomolecules on earth, and its partially de-N-acetylated counterpart, chitosan, is one of the most promising biotechnological resources due to its diversity in structure and function. Recently, chitin and chitosan modifying enzymes (CCMEs) have gained increasing interest as tools to engineer chitosans with specific functions and reliable performance in biotechnological and biomedical applications. In a search for novel CCME, we isolated chitinolytic and chitosanolytic microorganisms from soils with more than ten-years history of chitin and chitosan exposure and screened them for chitinase and chitosanase isoenzymes as well as for their patterns of oligomeric products by incubating their secretomes with chitosan polymers. Of the 60 bacterial strains isolated, only eight were chitinolytic and/or chitosanolytic, while 20 out of 25 fungal isolates were chitinolytic and/or chitosanolytic. The bacterial isolates produced rather similar patterns of chitinolytic and chitosanolytic enzymes, while the fungal isolates produced a much broader range of different isoenzymes. Furthermore, diverse mixtures of oligosaccharides were formed when chitosan polymers were incubated with the secretomes of select fungal species. Our study indicates that soils with a history of chitin and chitosan exposure are a good source of novel CCME for chitosan bioengineering. PMID:26273652

  11. Health status and relative exposure of mule deer and white-tailed deer to soil contaminants at the Rocky Mountain Arsenal

    SciTech Connect

    Creekmore, T.E.; Franson, J.C.; Whittaker, D.G.; Roy, R.R. |; Baker, D.L.

    1999-02-01

    The authors evaluated the health of 18 radio-collared deer [13 mule deer (Odocoileus hemionus) and 5 white-tailed deer (O. virginianus)] from the Rocky Mountain Arsenal, near Denver, Colorado, USA, a Superfund site contaminated with a variety of materials, including organochlorine pesticides, metals and nerve gas production by-products. Radio-collared deer were tracked for 1 to 3 years (1989--1992) to identify relative exposure to contaminants based on telemetry locations plotted on grid maps depicting known soil contaminant concentrations. At the end of the study, all animals were in fair or good body condition at the time of necropsy. Mean ages of mule deer and white-tailed deer were 7.4 and 10.6 years, respectively. At necropsy, tissues were collected from the deer for serology, histopathology, and analysis for eight chlorinated hydrocarbons and two metals. Detectable residues of mercury were found in the kidneys of 10 deer, dieldrin was found in fat, liver, and brain, and DDE was found in the muscle of one animal. Relative exposure estimates derived from telemetry and soil contamination data were correlated with tissue levels of dieldrin and mercury. Two mule deer had severe testicular atrophy, and one of these animals also had antler deformities. The prevalence of antibodies against epizootic hemorrhagic disease serotype 2 was 85%.

  12. Soil fungal community development in a high Arctic glacier foreland follows a directional replacement model, with a mid-successional diversity maximum

    PubMed Central

    Dong, Ke; Tripathi, Binu; Moroenyane, Itumeleng; Kim, Woosung; Li, Nan; Chu, Haiyan; Adams, Jonathan

    2016-01-01

    Directional replacement and directional non-replacement models are two alternative paradigms for community development in primary successional environments. The first model emphasizes turnover in species between early and late successional niches. The second emphasizes accumulation of additional diversity over time. To test whether the development of soil fungal communities in the foreland of an Arctic glacier conforms to either of these models, we collected samples from the Midtre Lovénbreen Glacier, Svalbard, along a soil successional series spanning >80 years. Soil DNA was extracted, and fungal ITS1 region was amplified and sequenced on an Illumina Miseq. There was a progressive change in community composition in the soil fungal community, with greatest fungal OTU richness in the Mid Stage (50–80 years). A nestedness analysis showed that the Early Stage (20–50 years) and the Late Stage (>80 years) fungal communities were nested within the Mid Stage communities. These results imply that fungal community development in this glacier succession follows a directional replacement model. Soil development processes may initially be important in facilitating arrival of additional fungal species, to give a mid-successional diversity maximum that contains both early- and late-successional fungi. Competition may then decrease the overall diversity due to the loss of early successional species. PMID:27240660

  13. Soil fungal community development in a high Arctic glacier foreland follows a directional replacement model, with a mid-successional diversity maximum.

    PubMed

    Dong, Ke; Tripathi, Binu; Moroenyane, Itumeleng; Kim, Woosung; Li, Nan; Chu, Haiyan; Adams, Jonathan

    2016-01-01

    Directional replacement and directional non-replacement models are two alternative paradigms for community development in primary successional environments. The first model emphasizes turnover in species between early and late successional niches. The second emphasizes accumulation of additional diversity over time. To test whether the development of soil fungal communities in the foreland of an Arctic glacier conforms to either of these models, we collected samples from the Midtre Lovénbreen Glacier, Svalbard, along a soil successional series spanning >80 years. Soil DNA was extracted, and fungal ITS1 region was amplified and sequenced on an Illumina Miseq. There was a progressive change in community composition in the soil fungal community, with greatest fungal OTU richness in the Mid Stage (50-80 years). A nestedness analysis showed that the Early Stage (20-50 years) and the Late Stage (>80 years) fungal communities were nested within the Mid Stage communities. These results imply that fungal community development in this glacier succession follows a directional replacement model. Soil development processes may initially be important in facilitating arrival of additional fungal species, to give a mid-successional diversity maximum that contains both early- and late-successional fungi. Competition may then decrease the overall diversity due to the loss of early successional species. PMID:27240660

  14. Coupling field observations, soil modeling, and air dispersion algorithms to estimate 1,3-dichloropropene and chloropicrin flux and exposure.

    PubMed

    Cryer, S A; van Wesenbeeck, I J

    2011-01-01

    Soil fumigants are volatile compounds applied to agricultural land to control nematode populations, weeds, and crop diseases. Field trials used for measuring fumigant loss from soil to the atmosphere encompass only a small proportion of the near semi-infinite parameter combinations of environmental, agronomic, and meteorological conditions. One approach to supplement field observations uses a soil physics model for fumigant emission predictions. A model is first validated against existing field study observations and then used to extrapolate results to a wider range of edaphic and climatic conditions. This work compares field observations of 1,3-dichloropropene and chloropicrin emissions to predictions from the USDA soil model CHAIN_2D. Comparison between model predictions and field observations for a Florida and California study had values between 0.62 to 0.81 and 0.99 to 1.0 for discrete and cumulative emission flux, respectively. CHAIN_2D emission rates were then coupled to several USEPA air dispersion models (ISCST3, CALPUFF6) to extend emission estimates to near field air concentrations. CALPUFF6 predicted slightly higher 1-h maximum air concentrations than ISCST3 for the same source strength (26.2-36.0% for setbacks between 1 and 250 m from the field edge, respectively). A sensitivity analysis for the CHAIN_2D/ISCST3 coupled numerical system is provided, with several soil and irrigation parameters consistently the most sensitive. Changes in the depth of incorporation, tarp material, and initial soil water content illustrate the predicted impact to emission strength and resulting near-field air concentrations with reductions of cumulative emission loss from 8.1 to 71% and average 1-h maximum air concentration reductions between 6.2 and 41% depending on the mitigation strategy chosen. Additionally, a stochastic framework based on the published SOFEA system that couples variability in experiment, model sensitivity, and site specific attributes is outlined should

  15. Exposure Information in Environmental Health Research: Current Opportunities and Future Directions for Particulate Matter, Ozone, and Toxic Air Pollutants

    EPA Science Inventory

    In September 2006, scientists from the US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health in ord...

  16. Soil experiment

    NASA Technical Reports Server (NTRS)

    Hutcheson, Linton; Butler, Todd; Smith, Mike; Cline, Charles; Scruggs, Steve; Zakhia, Nadim

    1987-01-01

    An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

  17. The Problem of Soil Erosion in Developing Countries--Direct and Indirect Causes and Recommendations for Reducing It to a Sustainable Level.

    ERIC Educational Resources Information Center

    Middlebrook, Cathy H.; Goode, Pamela M.

    1992-01-01

    Presents direct and indirect causes of erosion in developing countries. Identifies soil conservation developments ranging from major international policy reforms to small-scale, local farming programs. Suggests that strategies at all levels, and the political will to implement them, are needed if erosion is to be reduced to a sustainable rate. (23…

  18. A Closer Look at the Effects of Repeated Cocaine Exposure on Adaptive Decision-Making under Conditions That Promote Goal-Directed Control

    PubMed Central

    Halbout, Briac; Liu, Angela T.; Ostlund, Sean B.

    2016-01-01

    It has been proposed that compulsive drug seeking reflects an underlying dysregulation in adaptive behavior that favors habitual (automatic and inflexible) over goal-directed (deliberative and highly flexible) action selection. Rodent studies have established that repeated exposure to cocaine or amphetamine facilitates the development of habits, producing behavior that becomes unusually insensitive to a reduction in the value of its outcome. The current study more directly investigated the effects of cocaine pre-exposure on goal-directed learning and action selection using an approach that discourages habitual performance. After undergoing a 15-day series of cocaine (15 or 30 mg/kg, i.p.) or saline injections and a drug withdrawal period, rats were trained to perform two different lever-press actions for distinct reward options. During a subsequent outcome devaluation test, both cocaine- and saline-treated rats showed a robust bias in their choice between the two actions, preferring whichever action had been trained with the reward that retained its value. Thus, it appears that the tendency for repeated cocaine exposure to promote habit formation does not extend to a more complex behavioral scenario that encourages goal-directed control. To further explore this issue, we assessed how prior cocaine treatment would affect the rats’ ability to learn about a selective reduction in the predictive relationship between one of the two actions and its outcome, which is another fundamental feature of goal-directed behavior. Interestingly, we found that cocaine-treated rats showed enhanced, rather than diminished, sensitivity to this action–outcome contingency degradation manipulation. Given their mutual dependence on striatal dopamine signaling, we suggest that cocaine’s effects on habit formation and contingency learning may stem from a common adaptation in this neurochemical system. PMID:27047400

  19. A Closer Look at the Effects of Repeated Cocaine Exposure on Adaptive Decision-Making under Conditions That Promote Goal-Directed Control.

    PubMed

    Halbout, Briac; Liu, Angela T; Ostlund, Sean B

    2016-01-01

    It has been proposed that compulsive drug seeking reflects an underlying dysregulation in adaptive behavior that favors habitual (automatic and inflexible) over goal-directed (deliberative and highly flexible) action selection. Rodent studies have established that repeated exposure to cocaine or amphetamine facilitates the development of habits, producing behavior that becomes unusually insensitive to a reduction in the value of its outcome. The current study more directly investigated the effects of cocaine pre-exposure on goal-directed learning and action selection using an approach that discourages habitual performance. After undergoing a 15-day series of cocaine (15 or 30 mg/kg, i.p.) or saline injections and a drug withdrawal period, rats were trained to perform two different lever-press actions for distinct reward options. During a subsequent outcome devaluation test, both cocaine- and saline-treated rats showed a robust bias in their choice between the two actions, preferring whichever action had been trained with the reward that retained its value. Thus, it appears that the tendency for repeated cocaine exposure to promote habit formation does not extend to a more complex behavioral scenario that encourages goal-directed control. To further explore this issue, we assessed how prior cocaine treatment would affect the rats' ability to learn about a selective reduction in the predictive relationship between one of the two actions and its outcome, which is another fundamental feature of goal-directed behavior. Interestingly, we found that cocaine-treated rats showed enhanced, rather than diminished, sensitivity to this action-outcome contingency degradation manipulation. Given their mutual dependence on striatal dopamine signaling, we suggest that cocaine's effects on habit formation and contingency learning may stem from a common adaptation in this neurochemical system. PMID:27047400

  20. Assessing exposure to transformation products of soil-applied organic contaminants in surface water: comparison of model predictions and field data.

    PubMed

    Kern, Susanne; Singer, Heinz; Hollender, Juliane; Schwarzenbach, René P; Fenner, Kathrin

    2011-04-01

    Transformation products (TPs) of chemicals released to soil, for example, pesticides, are regularly detected in surface and groundwater with some TPs even dominating observed pesticide levels. Given the large number of TPs potentially formed in the environment, straightforward prioritization methods based on available data and simple, evaluative models are required to identify TPs with a high aquatic exposure potential. While different such methods exist, none of them has so far been systematically evaluated against field data. Using a dynamic multimedia, multispecies model for TP prioritization, we compared the predicted relative surface water exposure potential of pesticides and their TPs with experimental data for 16 pesticides and 46 TPs measured in a small river draining a Swiss agricultural catchment. Twenty TPs were determined quantitatively using solid-phase extraction liquid chromatography mass spectrometry (SPE-LC-MS/MS), whereas the remaining 26 TPs could only be detected qualitatively because of the lack of analytical reference standards. Accordingly, the two sets of TPs were used for quantitative and qualitative model evaluation, respectively. Quantitative comparison of predicted with measured surface water exposure ratios for 20 pairs of TPs and parent pesticides indicated agreement within a factor of 10, except for chloridazon-desphenyl and chloridazon-methyl-desphenyl. The latter two TPs were found to be present in elevated concentrations during baseflow conditions and in groundwater samples across Switzerland, pointing toward high concentrations in exfiltrating groundwater. A simple leaching relationship was shown to qualitatively agree with the observed baseflow concentrations and to thus be useful in identifying TPs for which the simple prioritization model might underestimate actual surface water concentrations. Application of the model to the 26 qualitatively analyzed TPs showed that most of those TPs categorized as exhibiting a high aquatic

  1. Microbial Transformation of Triadimefon to Triadimenol in Soils: Selective Production Rates of Triadimenol Stereoisomers Affect Exposure and Risk

    EPA Science Inventory

    The microbial transformation of triadimefon, an agricultural fungicide of the 1,2,4-triazole class, was followed at a nominal concentration of 50 μg/mL over 4 months under aerobic conditions in three different soil types. Rates and products of transformation were measured, as wel...

  2. REPRODUCTIVE FUNCTIONS AND HYPOTHALAMIC CATECHOLAMINES IN RESPONSE TO THE SOIL FUMIGANT METAM SODIUM: ADAPTATIONS TO EXTENDED EXPOSURES

    EPA Science Inventory

    Metam sodium (MS) is a soil fumigant and Category II pesticide with a relatively low toxicity in mammals. Previous data have shown an ability to impair reproductive mechanisms in ovariectomized, estradiol-primed rats. A single i.p. injection blocked the luteinizing hormone (LH) s...

  3. The exposure history of the Apollo 16 sites. An assessment based on methane and carbide measurements. [in lunar soils

    NASA Technical Reports Server (NTRS)

    Pillinger, C. T.; Eglinton, C.; Gowar, A. P.; Jull, A. J. T.; Maxwell, J. R.

    1974-01-01

    Soils from eight stations at the Apollo 16 landing site have been analyzed for methane and carbide. These results, in conjunction with published data from photogeology, bulk chemistry, rare gases, primordial and radionuclides, and agglutinate abundances have been interpreted in terms of differing contributions from three components, North and South Ray crater ejecta and Cayley Plains material.

  4. Soil Manganese Enrichment from Industrial Inputs: A Gastropod Perspective

    PubMed Central

    Bordean, Despina-Maria; Nica, Dragos V.; Harmanescu, Monica; Banatean-Dunea, Ionut; Gergen, Iosif I.

    2014-01-01

    Manganese is one of the most abundant metal in natural environments and serves as an essential microelement for all living systems. However, the enrichment of soil with manganese resulting from industrial inputs may threaten terrestrial ecosystems. Several studies have demonstrated harmful effects of manganese exposure by cutaneous contact and/or by soil ingestion to a wide range of soil invertebrates. The link between soil manganese and land snails has never been made although these invertebrates routinely come in contact with the upper soil horizons through cutaneous contact, egg-laying, and feeding activities in soil. Therefore, we have investigated the direct transfer of manganese from soils to snails and assessed its toxicity at background concentrations in the soil. Juvenile Cantareus aspersus snails were caged under semi-field conditions and exposed first, for a period of 30 days, to a series of soil manganese concentrations, and then, for a second period of 30 days, to soils with higher manganese concentrations. Manganese levels were measured in the snail hepatopancreas, foot, and shell. The snail survival and shell growth were used to assess the lethal and sublethal effects of manganese exposure. The transfer of manganese from soil to snails occurred independently of food ingestion, but had no consistent effect on either the snail survival or shell growth. The hepatopancreas was the best biomarker of manganese exposure, whereas the shell did not serve as a long-term sink for this metal. The kinetics of manganese retention in the hepatopancreas of snails previously exposed to manganese-spiked soils was significantly influenced by a new exposure event. The results of this study reveal the importance of land snails for manganese cycling in terrestrial biotopes and suggest that the direct transfer from soils to snails should be considered when precisely assessing the impact of anthropogenic Mn releases on soil ecosystems. PMID:24454856

  5. A survey of sources of incoherent artificial optical radiation in a hospital environment in accordance with European Directive 2006/25/EC: evaluation of the related exposure risk.

    PubMed

    Cavatorta, Claudia; Lualdi, Manuela; Meroni, Silvia; Polita, Giovanni; Bolchi, Mauro; Pignoli, Emanuele

    2016-03-01

    The evaluation of incoherent artificial optical radiation (AOR) exposure in hospital environments is a complex task due to the variety of sources available. This study has been designed to provide a proposal for the precautionary assessment of the related risk. This survey suggested that, in our Institution, at least three kinds of AOR sources required specific investigations: ambient lighting, theatre operating lighting and ultraviolet radiation (UVR) sources. For each kind of evaluated sources a specific measurement approach was developed. All irradiance measurements were made using a commercial spectroradiometer. The obtained results were compared with the appropriate exposure limit values (ELVs) defined in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines and adopted by the European Directive 2006/25/EC. The risk related to the evaluated AOR exposure was finally assessed according to our risk matrix. According to our results, the emission of ambient lighting in the actual exposure conditions was always in accordance with the ELVs and the related risk was classifiable as not relevant. The risk related to the exposure to theatre operating lighting resulted not negligible, especially when two or more sources were used with focal spots overlapping on reflective objects. UVR sources emission may represent a health hazard depending, in particular, on the set up of the device containing the source. In case of laminar flow cabinets and closed transilluminators, if the UVR source is well contained within an enclosure with interlock, it presents no risk of exposure. Otherwise, the emission arising from UVR lamps, open transilluminators or sources not provided with interlock, may represent a risk classifiable as high even in the actual working conditions. The personal protective equipment used by workers were also assessed and their suitability was discussed. PMID:26909554

  6. Carbon Loss and Germinability, Viability, and Virulence of Chlamydospores of Fusarium solani f. sp. phaseoli After Exposure to Soil at Different pH Levels, Temperatures, and Matric Potentials.

    PubMed

    Mondal, S N; Hyakumachi, M

    1998-02-01

    ABSTRACT (14)C-labeled chlamydospores of Fusarium solani f. sp. phaseoli were exposed to soil at 5, 15, 25, or 30 degrees C at pH 5 or 8 and water potential of -1 kPa or to soil at 0, -1, or -10 kPa at 25 degrees C at pH 6.9. Total carbon loss was greatest at 25 or 30 degrees C at pH 8 and -1 kPa. (14)CO(2) from respiration of chlamydospores and from soil microbes utilizing chlamydospore exudates accounted for the largest share of total carbon loss under all conditions. (14)(CO)(2) from soil microbial metabolism of (14)CO(2) exudates of chlamydospores was greatest in soil at 15, 25, and 30 degrees C, pH 8, and at either -1 or -10 kPa. Chlamydospore germinability in the absence of a C source (nutrient independence), viability in potato-dextrose broth, and virulence to kidney bean declined rapidly after exposure to soil at high temperatures (25 and 30 degrees C), pH 8, and the higher matric potentials (0 to-1 kPa). By contrast, germinability remained high (>50%), as did virulence, in soil at 5 degrees C and -10 kPa even after 70 days of incubation. Carbon loss was inversely correlated with germinability, viability, and virulence after exposure to soil at different pH levels, temperatures, and matric potentials. PMID:18944984

  7. Frequency and Characteristics Associated With Exposure to Tobacco Direct Mail Marketing and Its Prospective Effect on Smoking Behaviors Among Young Adults From the US Midwest

    PubMed Central

    Forster, Jean L.

    2014-01-01

    Objectives. We examined the exposure to tobacco direct mail marketing and its effect on subsequent smoking behaviors in a US Midwest regional cohort of young adults. Methods. Data were collected from 2622 young adults (mean age = 24 years) in 2010 to 2011 (baseline) and 2011 to 2012 (follow-up). We collected information on demographics, tobacco use, and exposure to tobacco direct mail materials in the previous 6 months at baseline. Smoking behaviors were reassessed at follow-up. We investigated the characteristics associated with receiving these materials at baseline, and the associations between receiving cigarette coupons in the mail at baseline and smoking behaviors at follow-up. Results. Thirteen percent of participants reported receiving tobacco direct mail materials in the previous 6 months. Receipt of these materials was associated with age, education, and tobacco use (P < .05). Among those who received these materials, 77% and 56% reported receiving coupons for cigarettes and other tobacco products, respectively. Among baseline nonsmokers and ex-smokers, receiving coupons was associated with becoming current smokers at follow-up (P < .05). Among baseline current smokers, receiving coupons was associated with lower likelihood of smoking cessation at follow-up (P < .05). Conclusions. Tobacco direct mail marketing promoted and sustained smoking behaviors among US Midwest young adults. Regulating this marketing strategy might reduce the prevalence of smoking in this population. PMID:25211739

  8. Evaluation of E-Cigarette Liquid Vapor and Mainstream Cigarette Smoke after Direct Exposure of Primary Human Bronchial Epithelial Cells

    PubMed Central

    Scheffler, Stefanie; Dieken, Hauke; Krischenowski, Olaf; Förster, Christine; Branscheid, Detlev; Aufderheide, Michaela

    2015-01-01

    E-cigarettes are emerging products, often described as “reduced-risk” nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5–8 times lower and the oxidative stress levels 4.5–5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user. PMID:25856554

  9. The potential for human exposure, direct and indirect, to the suspected carcinogenic triphenylmethane dye Brilliant Green from green paper towels.

    PubMed

    Oplatowska, Michalina; Donnelly, Ryan F; Majithiya, Rita J; Glenn Kennedy, D; Elliott, Christopher T

    2011-08-01

    Triphenylmethanes - Malachite Green (MG), Crystal Violet (CV) and Brilliant Green (BG) are dyes with known genotoxic and carcinogenic properties. Apart from being illegally used in aquaculture for treatment of fish diseases they are also applied in industry such as paper production to colour paper towels widely used in hospitals, factories and other locations for hand drying after washing. The present study provides evidence that the triphenylmethane dye (BG) present in green paper towels can migrate through the skin even when the exposure time is short (30-300 s). The transfer of the dye from the towel to food (fish) was also studied and a high amount of colour was found to migrate during overnight exposure. The risk to humans associated with these two dye transfer studies was assessed using a 'margin of exposure approach' on the basis of the toxicological data available for the closely related dye MG and its metabolite Leucomalachite Green. The data indicated that the risk associated with the use of triphenylmethane containing paper towels is of a similar proportion to the risk associated with consumption of fish contaminated with these dyes due to the illegal application in aquaculture. PMID:21596089

  10. Propanil Exposure Induces Delayed but Sustained Abrogation of Cell-Mediated Immunity through Direct Interference with Cytotoxic T-Lymphocyte Effectors

    PubMed Central

    Sheil, James M.; Frankenberry, Marc A.; Schell, Todd D.; Brundage, Kathleen M.; Barnett, John B.

    2006-01-01

    The postemergent herbicide propanil (PRN; also known as 3,4-dichloropropionanilide) is used on rice and wheat crops and has well-known immunotoxic effects on various compartments of the immune system, including T-helper lymphocytes, B lymphocytes, and macrophages. It is unclear, however, whether PRN also adversely affects cytotoxic T lymphocytes (CTLs), the primary (1°) effectors of cell-mediated immunity. In this study we examined both the direct and indirect effects of PRN exposure on CTL activation and effector cell function to gauge its likely impact on cell-mediated immunity. Initial experiments addressed whether PRN alters the class I major histocompatibility complex (MHC) pathway for antigen processing and presentation by antigen-presenting cells (APCs), thereby indirectly affecting effector function. These experiments demonstrated that PRN does not impair the activation of CTLs by PRN-treated APCs. Subsequent experiments addressed whether PRN treatment of CTLs directly inhibits their activation and revealed that 1° alloreactive CTLs exposed to PRN are unimpaired in their proliferative response and only marginally inhibited in their lytic activity. Surprisingly, secondary stimulation of these alloreactive CTL effectors, however, even in the absence of further PRN exposure, resulted in complete abrogation of CTL lytic function and a delayed but significant long-term effect on CTL responsiveness. These findings may have important implications for the diagnosis and clinical management of anomalies of cell-mediated immunity resulting from environmental exposure to various herbicides and other pesticides. PMID:16835059

  11. Oral relative bioavailability of Dichlorodiphenyltrichloroethane (DDT) in contaminated soil and its prediction using in vitro strategies for exposure refinement.

    PubMed

    Juhasz, Albert L; Herde, Paul; Smith, Euan

    2016-10-01

    In this study, the bioavailability of DDTr (sum of DDT, DDD and DDE isomers) in pesticide-contaminated soil was assessed using an in vivo mouse model. DDTr relative bioavailability (RBA) ranged from 18.7±0.9 (As35) to 60.8±7.8% (As36) indicating that a significant portion of soil-bound DDTr was not available for absorption following ingestion. When DDTr bioaccessibility was assessed using the organic Physiologically Based Extraction Test (org-PBET), the inclusion of a sorption sink (silicone cord) enhanced DDTr desorption by up to 20-fold (1.6-3.8% versus 18.9-56.3%) compared to DDTr partitioning into gastrointestinal fluid alone. Enhanced desorption occurred as a result of the silicone cord acting as a reservoir for solubilized DDTr to partition into, thereby creating a flux for further desorption until equilibrium was achieved. When the relationship between in vivo and in vitro data was assessed, a strong correlation was observed between the mouse bioassay and the org-PBET+silicone cord (slope=0.94, y-intercept=3.5, r(2)=0.72) suggesting that the in vitro approach may provide a robust surrogate measure for the prediction of DDTr RBA in contaminated soil. PMID:27423050

  12. USEPA METHOD STUDY 37 - SW-846 METHOD 3050, ACID DIGESTION OF SEDIMENTS, SLUDGES AND SOILS BY AA-DIRECT ASPIRATION

    EPA Science Inventory

    An interlaboratory collaborative study was conducted to determine the precision and accuracy of Method 3050 for the analysis of 23 elements in sediments, sludqes and soils. Method 3050 is entitled, "Acid Digestion of Sediments, Sludges and Soils." It includes instructions for qua...

  13. Lime effects on soil acidity, crop yield and aluminum chemistry in inland Pacific Northwest direct-seed cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pH of agricultural soils in the Inland Pacific Northwest (IPNW) has declined below established critical levels for cereal and grain legume crops. Our objective was to assess the effects of broadcast or subsurface banded lime treatments on soil acidity, crop yield, and aluminum (Al) chemistry in ...

  14. Comparative study of neurologic effects of nano-TiO2 versus SiO2 after direct intracerebral exposure in mice

    NASA Astrophysics Data System (ADS)

    Balvay, A.; Thieriet, N.; Lakhdar, L.; Bencsik, A.

    2013-04-01

    Titanium and silicon dioxide nanoparticles (TiO2 and SiO2 NPs) are now in daily use in many commercial products of which food, sunscreens, toothpastes or cosmetics. However, their effects on human body, especially on the central nervous system, are still unclear. The aim of this study was to determine whether direct exposition of the brain to TiO2 and SiO2 NPs results in alternations in nervous system function. C57Bl6 mice were exposed to 5 and 10 μg doses of TiO2 and SiO2 NPs through intracerebroventricular administration using a stereotaxic approach. Then the neurologic effects were investigated using motor performance parameters, measured on a rotarod at 20 rpm or at an accelerating rod (from 4 to 40 rpm). Before and after injection, motor activity is registered individually for each mouse exposed, once a week, for 8 weeks. Besides, a group of 3 mice is culled at 1, 2, 3, 4 and 8 weeks after exposure in order to study the time dependant effect on the histopathology of the brain (gliosis, inflammatory process...). Both rotarod tests (accelerating and at 20 rpm) showed that TiO2 and SiO2 NPs exposure could significantly impair the motor performances, even several weeks after initial acute exposure. The first examination of the brain histopathology revealed microglial activation. As it appeared to grow throughout the brain in a time dependant manner this suggests the induction of a long lasting neuroinflammation. These primary findings indicated that exposure to TiO2 and SiO2 NPs could possibly impair the locomotor ability and this deficit may be possibly attributed at least to an inflammatory process maintained till 8 weeks after exposure in the mouse brain. To fully investigate the neurotoxicological consequences of TiO2 and SiO2 NPs exposure, brain contents in these NPs will be also investigated as well as other alterations like neurotransmitter levels. These preliminary data already underline the necessity of more in vivo studies to better characterize TiO2

  15. Integrated community-directed intervention for schistosomiasis and soil transmitted helminths in western Kenya – a pilot study

    PubMed Central

    2012-01-01

    Background Schistosome and soil-transmitted helminth (STH) infections are recognized as major global public health problems, causing severe and subtle morbidity, including significant educational and nutritional effects in children. Although effective and safe drugs are available, ensuring access to these drugs by all those at risk of schistosomiasis and STHs is still a challenge. Community-directed intervention (CDI) has been used successfully for mass distribution of drugs for other diseases such as onchocerciasis and lymphatic filariasis. A national control programme is yet to be instituted in Kenya and evidence for cost-effective strategies for reaching most affected communities is needed. This study evaluated the effectiveness and feasibility of the CDI strategy in the control of schistosomiasis and STHs, in East Uyoma location, Rarieda district, a community of western Kenya that is highly endemic for both infections. Results Pre-treatment prevalence of S. mansoni averaged 17.4% (range 5-43%) in the entire location. Treatment coverage in different villages ranged from 54.19 to 96.6% by community drug distributor (CDD) records. Assessment from a household survey showed coverage of 52.3 -91.9% while the proportion of homesteads (home compounds) covered ranged from 54.9-98.5%. Six months after one round of drug distribution, the prevalence levels of S. mansoni, hookworm and Trichuris trichura infections were reduced by 33.2%, 69.4% and 42.6% respectively. Conclusions This study shows that CDI is an accepted and effective strategy in the mass treatment of schistosomiasis and STH infections in resource constrained communities in Kenya and may be useful in similar communities elsewhere. A controlled trial comparing CDI and school based mass drug administration to demonstarte their relative advantages is ongoing. PMID:22937890

  16. Effect of rainfall and tillage direction on the evolution of surface crusts, soil hydraulic properties and runoff generation for a sandy loam soil

    NASA Astrophysics Data System (ADS)

    Ndiaye, Babacar; Esteves, Michel; Vandervaere, Jean-Pierre; Lapetite, Jean-Marc; Vauclin, Michel

    2005-06-01

    The study was aimed at evaluating the effect of rainfall and tillage-induced soil surface characteristics on infiltration and runoff on a 2.8 ha catchment located in the central region of Senegal. This was done by simulating 30 min rain storms applied at a constant rate of about 70 mm h -1, on 10 runoff micro-plots of 1 m 2, five being freshly harrowed perpendicularly to the slope and five along the slope (1%) of the catchment. Runoff was automatically recorded at the outlet of each plot. Hydraulic properties such as capillary sorptivity and hydraulic conductivity of the sandy loam soil close to saturation were determined by running 48 infiltration tests with a tension disc infiltrometer. That allowed the calculation of a mean characteristic pore size hydraulically active and a time to ponding. Superficial water storage capacity was estimated using data collected with an electronic relief meter. Because the soil was subject to surface crusting, crust-types as well as their spatial distribution within micro-plots and their evolution with time were identified and monitored by taking photographs at different times after tillage. The results showed that the surface crust-types as well as their tillage dependent dynamics greatly explain the decrease of hydraulic conductivity and sorptivity as the cumulative rainfall since tillage increases. The exponential decaying rates were found to be significantly greater for the soil harrowed along the slope (where the runoff crust-type covers more than 60% of the surface after 140 mm of rain) than across to the slope (where crusts are mainly of structural (60%) and erosion (40%) types). That makes ponding time smaller and runoff more important. Also it was shown that soil hydraulic properties after about 160 mm of rain were close to those of untilled plot not submitted to any rain. That indicates that the effects of tillage are short lived.

  17. Direct observation of von Willebrand factor elongation and fiber formation on collagen during acute whole blood exposure to pathological flow

    PubMed Central

    Colace, T. V.; Diamond, S. L.

    2013-01-01

    Objective In severe stenosis, von Willebrand Factor (vWF) experiences millisecond exposures to pathological wall shear rates (γw). We sought to evaluate the deposition of vWF onto collagen surfaces under flow in these environments. Methods and Results Distinct from shear experiments that last many seconds, we deployed microfluidic devices for single-pass perfusion of whole blood or platelet free plasma (PFP) over fibrillar type 1 collagen (< 50 msec transit time) at pathological γw or spatial wall shear rate gradient (grad γw). Using fluorescent anti-vWF, long thick vWF fibers (>20 μm) bound to collagen were visualized at constant γw > 30,000 s−1 during perfusion of PFP, a process enhanced by EDTA. Rapid acceleration or deceleration of EDTA-PFP at grad γw = ± 5.5 × 105 to 4.3 × 107 s−1/cm did not promote vWF deposition. At 19,400 s−1, EDTA-blood perfusion resulted in rolling vWF-platelet nets, while blood perfusion (normal Ca2+) generated large vWF/platelet deposits that repeatedly embolized and were blocked by anti-GPIb or the α IIbβ3 inhibitor GR144053 and did not require grad γw. Blood perfusion at venous shear rate (200 s−1) produced a stable platelet deposit that was a substrate for massive but unstable vWF-platelet aggregates when flow was increased to 7800 s−1. Conclusion Triggered by collagen and enhanced by platelet GPIb and α IIbβ3, vWF fiber formation occurred during acute exposures to pathological γw and did not require gradients in wall shear rate. PMID:23104847

  18. Phytoremediation of lead (Pb) and arsenic (As) by Melastoma malabathricum L. from contaminated soil in separate exposure.

    PubMed

    Selamat, S Norleela; Abdullah, S Rozaimah Sheikh; Idris, M

    2014-01-01

    This study was conducted to investigate the uptake of lead (Pb) and arsenic (As) from contaminated soil using Melastoma malabathricum L. species. The cultivated plants were exposed to As and Pb in separate soils for an observation period of 70 days. From the results of the analysis, M. malabathricum accumulated relatively high range of As concentration in its roots, up to a maximum of 2800 mg/kg. The highest accumulation of As in stems and leaves was 570 mg/kg of plant. For Pb treatment, the highest concentration (13,800 mg/kg) was accumulated in the roots of plants. The maximum accumulation in stems was 880 mg/kg while maximum accumulation in leaves was 2,200 mg/kg. Only small amounts of Pb were translocated from roots to above ground plant parts (TF < 1). However, a wider range of TF values (0.01-23) for As treated plants proved that the translocation of As from root to above ground parts was greater. However, the high capacity of roots to take up Pb and As (BF > 1) is indicative this plants is a good bioaccumulator for these metals. Therefore, phytostabilisation is the mechanism at work in M. malabathricum's uptake of Pb, while phytoextraction is the dominant mechanism with As. PMID:24933879

  19. FATE AND EXPOSURE MODELING IN TERRESTRIAL ECOSYSTEMS: A PROCESS APPROACH

    EPA Science Inventory

    Pathways for exposure of birds to pesticides include soil, water, air, soil-dwelling organisms, and insects. rocess approach to avian exposure calculates transport and transformation of agricultural chemicals through each of the exposure media. ifferential equations calculating t...

  20. Ecological assessment of soil using a soil elutriate and the perennial ryegrass, Lolium perenne

    SciTech Connect

    Lawrence, C.; Meyers-Shone, L.; Duh, D.

    1995-12-31

    A 28-day plant bioassay using the perennial ryegrass, Lolium perenne, was utilized for an ecological assessment of soil from a hazardous waste site. An elutriate of the test soil was prepared and nutrients added, so that the seedlings would have direct exposure via uptake and to control for poor plant growth due to a lack of nutrients or proper soil profile characteristics. Use of an elutriate as the exposure medium assumes that those contaminants that can become waterborne for uptake by plants in the site conditions is the same as those which can be separated from adsorption to soil particulates during elutriate preparation. The ryegrass seeds were planted in a hydroponic system consisting of an upper chamber with an inert soil for a growth matrix and a lower reservoir with the nutrient and soil elutriate. Polyester cords were used to continuously wick the solution up to the inert soil and the chambers were drenched twice daily with the solution in the reservoir. At the conclusion of the study the plants` shoot length and dry weight (biomass) were measured to assess phytotoxicity of constituents in soil. The results of the test plants parameters were statistically compared to control plants to determine if test soil elutriates caused a measurable effect on ryegrass, The results of this plant bioassay provided additional and useful information for assessment of test soil.

  1. Soils and public health: the vital nexus

    NASA Astrophysics Data System (ADS)

    Pachepsky, Yakov

    2015-04-01

    Soils sustain life. They affect human health via quantity, quality, and safety of available food and water, and via direct exposure of individuals to soils. Throughout the history of civilization, soil-health relationships have inspired spiritual movements, philosophical systems, cultural exchanges, and interdisciplinary interactions, and provided medicinal substances of paramount impact. Given the climate, resource, and population pressures, understanding and managing the soil-health interactions becomes a modern imperative. We are witnessing a paradigm shift from recognizing and yet disregarding the 'soil-health' nexus complexity to parameterizing this complexity and identifying reliable controls. This becomes possible with the advent of modern research tools as a source of 'big data' on multivariate nonlinear soil systems and the multiplicity of health metrics. The phenomenon of suppression of human pathogens in soils and plants presents a recent example of these developments. Evidence is growing about the dependence of pathogen suppression on the soil microbial community structure which, in turn, is affected by the soil-plant system management. Soil eutrophication appears to create favorable conditions for pathogen survival. Another example of promising information-rich research considers links and feedbacks between the soil microbial community structure and structure of soil physical pore space. The two structures are intertwined and involved in the intricate self-organization that controls soil services to public health. This, in particular, affects functioning of soils as a powerful water filter and the capacity of this filter with respect to emerging contaminants in both 'green' and 'blue' waters. To evaluate effects of soil services to public health, upscaling procedures are needed for relating the fine-scale mechanistic knowledge to available coarse-scale information on soil properties and management. More needs to be learned about health effects of soils

  2. An extensive cocktail approach for rapid risk assessment of in vitro CYP450 direct reversible inhibition by xenobiotic exposure.

    PubMed

    Spaggiari, Dany; Daali, Youssef; Rudaz, Serge

    2016-07-01

    Acute exposure to environmental factors strongly affects the metabolic activity of cytochrome P450 (P450). As a consequence, the risk of interaction could be increased, modifying the clinical outcomes of a medication. Because toxic agents cannot be administered to humans for ethical reasons, in vitro approaches are therefore essential to evaluate their impact on P450 activities. In this work, an extensive cocktail mixture was developed and validated for in vitro P450 inhibition studies using human liver microsomes (HLM). The cocktail comprised eleven P450-specific probe substrates to simultaneously assess the activities of the following isoforms: 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 2J2 and subfamily 3A. The high selectivity and sensitivity of the developed UHPLC-MS/MS method were critical for the success of this methodology, whose main advantages are: (i) the use of eleven probe substrates with minimized interactions, (ii) a low HLM concentration, (iii) fast incubation (5min) and (iv) the use of metabolic ratios as microsomal P450 activities markers. This cocktail approach was successfully validated by comparing the obtained IC50 values for model inhibitors with those generated with the conventional single probe methods. Accordingly, reliable inhibition values could be generated 10-fold faster using a 10-fold smaller amount of HLM compared to individual assays. This approach was applied to assess the P450 inhibition potential of widespread insecticides, namely, chlorpyrifos, fenitrothion, methylparathion and profenofos. In all cases, P450 2B6 was the most affected with IC50 values in the nanomolar range. For the first time, mixtures of these four insecticides incubated at low concentrations showed a cumulative inhibitory in vitro effect on P450 2B6. PMID:27105555

  3. Conversion coefficients for age-dependent ORNL phantoms from 137Cs in soil as a source of external exposure

    NASA Astrophysics Data System (ADS)

    Krstic, D.; Nikezic, D.

    2007-09-01

    Dose conversion coefficients for different organs of age-dependent ORNL phantoms, due to the 137Cs in soil have been calculated using the MCNP-4B code. A cylindrical source at a depth of 20 cm was subdivided into 10 smaller cylinders, each of height 2 cm. Any one of these smaller cylinders could be considered as a source of photons with the energies of 661.6 keV. The ORNL phantoms stand exactly above the center of the cylinders. MCNP-4B energy deposition tally (F6) in MeV/g per one emitted photon was used to calculate absorbed doses in organs of phantoms. Then, conversion of units was made to obtain absorbed dose in fGy (femto-Gray) per Bq s kg -1. Absorbed doses in all major organs and the remainder, defined in reports ICRP60 and 74, were calculated as a function of the 137Cs source depth. Conversion coefficients decrease as the phantom age increases.

  4. Agronomic and remedial benefits and risks of applying biochar to soil: Current knowledge and future research directions.

    PubMed

    Kuppusamy, Saranya; Thavamani, Palanisami; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

    2016-02-01

    'Biochar' represents an emerging technology that is increasingly being recognized for its potential role in carbon sequestration, reducing greenhouse gas emissions, waste management, renewable energy, soil improvement, crop productivity enhancement and environmental remediation. Published reviews have so far focused mainly on the above listed agronomic and environmental benefits of applying biochar, yet paid little or no attention to its harmful effects on the ecological system. This review highlights a balanced overview of the advantages and disadvantages of the pyrolysis process of biochar production, end-product quality and the benefits versus drawbacks of biochar on: (a) soil geochemistry and albedo, (b) microflora and fauna, (c) agrochemicals, (d) greenhouse gas efflux, (e) nutrients, (f) crop yield, and (g) contaminants (organic and inorganic). Future research should focus more on the unintended long-term consequences of biochar on biological organisms and their processes in the soil. PMID:26638014

  5. Acute Illness Associated with Exposure to a New Soil Fumigant Containing Dimethyl Disulfide-Hillsborough County, Florida, 2014.

    PubMed

    Mulay, Prakash R; Cavicchia, Philip; Watkins, Sharon M; Tovar-Aguilar, Antonio; Wiese, Michael; Calvert, Geoffrey M

    2016-01-01

    Dimethyl disulfide (DMDS) is a new soil fumigant that is considered a replacement for methyl bromide. In 2014, the Florida Department of Health (FDOH) received several complaints of illness following a strong DMDS odor in Hillsborough County. Public health investigation of DMDS-related illness was conducted to assess illness and identify areas to target for prevention activities. This investigation included surveillance, interviews, review of medical records, review of supporting documentation, and determination of pesticide-related illness and injury case status. FDOH interviewed 66 people complaining of illness related to DMDS. Thirty-two were classified as possible and 11 as suspicious cases of DMDS-related illness. Among cases, the mean age was 48 years (range: 3-71 years). The majority were non-Hispanic (n = 43, 100%), white (n = 40, 93%), and female (n = 23, 53.5%). The most common signs and symptoms reported by exposed people included eye pain, throat irritation, nausea, dizziness, headache, and fatigue. There were 88% of cases classified as having low severity of illness and 12% classified as having moderate severity. The average distance from an application site among individuals who reported being exposed at or near their home was 0.74 miles for those classified as cases (n = 36) and 2.84 miles for those not classified as cases (n = 21, P < .05). This is the first known comprehensive report of DMDS-related illness in humans. Even though illnesses associated with DMDS in this investigation were generally of low severity, it is important to identify better ways to prevent off-target movement of DMDS and to improve notification to communities when nearby DMDS applications are planned. PMID:27409156

  6. Risk assessment of soil-based exposures to plutonium at experimental sites located on the Nevada Test Site and adjoining areas

    SciTech Connect

    Layton, D.W.; Anspaugh, L.R.; Bogen, K.T.; Straume, T.

    1993-06-01

    In the late 1950s and early 1960s, a series of tests was conducted at or near the Nevada Test Site to study issues involving plutonium-bearing devices. These tests resulted in the dispersal of about 5 TBq of {sup 239,240}Pu on the surficial soils at the test locations. Access to the sites is strictly controlled; therefore, it does not constitute a threat to human health at the present time. However, because the residual {sup 239} Pu decays slowly (half-life of 24,110 y), the sites could indeed represent a long-term hazard if they are not remediated and if institutional controls are lost. To investigate the magnitude of the potential health risks for this no-remediation case, we defined three basic exposure scenarios that could bring individuals in contact with {sup 239,240}Pu at the sites: (1) a resident living in a subdivision located at a test site, (2) a resident farmer, and (3) a worker at a commercial facility. Our screening analyses indicated that doses to organs are dominated by the intemal deposition of Pu via the inhalation pathway, and thus our risk assessment focused on those factors that affect inhalation exposures and associated doses, including inhalation rates, activity patterns, tenure at a residence or occupation, indoor/outdoor air relationships, and resuspension outdoors. Cancer risks were calculated as a function of lifetime cumulative doses to the key target organs (i.e., bone surface, liver, and lungs) and risk factors for those organs. Uncertainties in the predicted cancer risks were analyzed using Monte-Carlo simulations of the probability distributions used to represent assessment parameters. The principal sources of uncertainty in the estimated risks were population mobility, the relationship between indoor and outdoor contaminant levels, and the dose and risk factors for bone, liver, and lung.

  7. Biotoxicity of Mars Analog Soils: Microbial, Dispersal into Desiccated Soils Versus Emplacement in Salt or Ice Inclusions Fluids

    NASA Technical Reports Server (NTRS)

    Schuerger, A. C.; Ming, Doutlas W.; Golden, D. C.

    2010-01-01

    Recent evidence from the Opportunity and Spirit rovers and the Mars Express mission suggests that the soils on Mars might be very high in biotoxic materials including sulfate salts, chlorides, and acidifying agents. Yet, very little is known about how the chemistries of Mars soils might affect the survival and growth of terrestrial microorganisms. The primary objectives of the research included: (1) prepare and characterize Mars analog soils amended with potential biotoxic levels of sulfates, chlorides, and acidifying minerals; and (2) use the simulants to conduct a series of toxicology assays to determine if terrestrial microorganisms from spacecraft can survive direct exposure to the biotoxic soils.

  8. Cross calibration of new x-ray films against direct exposure film from 1 to 8 keV using the X-pinch x-ray source

    SciTech Connect

    Chandler, K.M.; Pikuz, S.A.; Shelkovenko, T.A.; Mitchell, M.D.; Hammer, D.A.; Knauer, J.P.

    2005-11-15

    A cross calibration of readily available x-ray sensitive films has been carried out against the calibrated direct exposure film (DEF) which is no longer being manufactured by Kodak. Four-wire X pinches made from various metal wires were used as x-ray sources for this purpose. Tests were carried out for the Kodak films Biomax MS, Biomax XAR, M100, Technical Pan, and T-Max over the energy range of 1-8 keV (12.4-1.5 A wavelength). The same hand-development procedures as described by Henke et al. [J. Opt. Soc. Am. B 3, 1540 (1986)] were followed for all films in every test. Sensitivity curves as a function of wavelength for these films relative DEF are presented. These relative calibrations show that Biomax MS is likely to be the best replacement film for DEF for most purposes over the energy range tested here.

  9. Cross calibration of new x-ray films against direct exposure film from 1 to 8 keV using the X-pinch x-ray source

    NASA Astrophysics Data System (ADS)

    Chandler, K. M.; Pikuz, S. A.; Shelkovenko, T. A.; Mitchell, M. D.; Hammer, D. A.; Knauer, J. P.

    2005-11-01

    A cross calibration of readily available x-ray sensitive films has been carried out against the calibrated direct exposure film (DEF) which is no longer being manufactured by Kodak. Four-wire X pinches made from various metal wires were used as x-ray sources for this purpose. Tests were carried out for the Kodak films Biomax MS, Biomax XAR, M100, Technical Pan, and T-Max over the energy range of 1-8keV (12.4-1.5Å wavelength). The same hand-development procedures as described by Henke et al. [J. Opt. Soc. Am. B 3, 1540 (1986)] were followed for all films in every test. Sensitivity curves as a function of wavelength for these films relative DEF are presented. These relative calibrations show that Biomax MS is likely to be the best replacement film for DEF for most purposes over the energy range tested here.

  10. Rapid onset of peripheral artery disease in a chronic myeloid leukemia patient without prior arterial disorder: direct relationship with nilotinib exposure and clinical outcome.

    PubMed

    Mirault, Tristan; Rea, Delphine; Azarine, Arshid; Messas, Emmanuel

    2015-04-01

    The second-generation tyrosine kinase inhibitor (TKI) of the BCR-ABL1 oncoprotein nilotinib used in patients with chronic myeloid leukemia is suspected to increase the risk of arterial occlusion, especially in patients with pre-existing cardiovascular risk factors or established cardiovascular diseases. Here, we describe a case of unexpected and rapid onset of symptomatic peripheral artery disease (PAD) associated with silent stenosis of digestive and renal arteries in a nilotinib-treated patient devoid of significant cardiovascular diseases (CVD) risk factor, prior atherosclerotic disease, or other cause of arterial damage. This is the first report to establish a direct relationship between nilotinib exposure and PAD and to reveal that arterial damage is irreversible despite rapid drug withdrawal. However, functional outcome was favorable upon rapid TKI replacement, specific cardiovascular disease management, and development of collateral arterial network. PMID:24797802

  11. Final Technical Report: Optimization and Directed, Natural Evolution of Biologically-Mediated Chromate Reduction in Subsurface Soil Microcosms

    SciTech Connect

    Thompson, Dorothea K; Wickham, Gene S; Layton, Alice C

    2012-07-27

    The U.S. Department of Energy (DOE) is faced with the complex challenge of remediating or containing the various mixed wastes present in the subsurface environments of numerous DOE sites. The development of scientifically grounded strategies for the effective management and reclamation of these contaminated sites requires fundamental knowledge on the composition, dynamics, and metabolic potential of indigenous microbial communities, which are of primary importance in the fate and transport of heavy metals and radionuclides in subsurface environments. To date, the complex effect of environmental (both geochemical and biological) parameters on the bioremediative potential of subsurface microbial populations is only partially understood; this is primarily because the majority of microbial ecological studies have focused only on a qualitative analysis of subsurface microbial diversity, while the impact of quantitative changes in microbial communities as a function of environmental factors has been ignored. The project described here directly addresses the need for a more comprehensive, molecular understanding of how microbial growth and activity quantitatively relate to mineral and contaminant biotransformation (Science Element: Subsurface Microbial Ecology and Community, Notice DE-FG02-06ER06-12). The proposed study uses a truly novel combination of standard molecular phylogenetic analyses, rRNA-targeted fluorescence in situ hybridization, and mass spectrometry (MS)-based proteomics to investigate the biological response to experimentally controlled conditions and the concomitant effect on chromate reduction in situ. This response will be characterized in terms of microbial community structure (principally, population number and spatial distribution) and community proteome dynamics. Towards this overarching goal, we will (1) set up aerobic and anaerobic laboratory microcosms derived from subsurface soil collected from a chromate [Cr(VI)]-contaminated DOE site, and

  12. Antioxidant and gene expression responses of Eisenia fetida following repeated exposure to BDE209 and Pb in a soil-earthworm system.

    PubMed

    Hu, Shuangqing; Zhang, Wei; Li, Jing; Lin, Kuangfei; Ji, Rong

    2016-06-15

    This study first adopted repeated treatment model to investigate stress responses in earthworms (Eisenia fetida) following exposure to decabromodiphenyl ether (BDE209) and lead (Pb), which are the mainly co-existed contaminants at e-waste recycling sites. We evaluated the impacts of BDE209-Pb on antioxidative enzyme (superoxide dismutase, SOD; catalase, CAT) activities, malondialdehyde (MDA) contents and transcriptional levels of three target genes (SOD, CAT and Hsp70), and further explored the relationships among these biomarkers. Results demonstrated that almost all the parameters were generally induced and the responses followed certain dose-effect relationships. Compared to the controls, a significant (P<0.05) up-regulation trend of expression levels of the three genes could be clearly observed after 14days incubation. Additionally, there existed good correlations between target genes expression levels and antioxidant enzyme activities (R>0.64). The observations could provide important information of ecotoxicological effects of BDE209-Pb in a soil-earthworm system as well as the mechanism of antioxidant defense. PMID:26971217

  13. The effect of long-term Cd and Ni exposure on seed endophytes of Agrostis capillaris and their potential application in phytoremediation of metal-contaminated soils.

    PubMed

    Truyens, S; Jambon, I; Croes, S; Janssen, J; Weyens, N; Mench, M; Carleer, R; Cuypers, A; Vangronsveld, J

    2014-01-01

    We examined whether long-term Cd exposure leads to beneficial changes in the cultivable endophytic bacteria present in the seeds of Agrostis capillaris. Therefore the cultivable seed endophytes of Agrostis capillaris growing on a long-term Cd/Ni-contaminated plot (Cd/Ni seeds) were compared with those originating from a non-contaminated plot (control seeds). We observed plant- and contaminant-dependent effects on the population composition between control and Cd/Ni seeds. Also differences in phenotypic characteristics were found: endophytes from Cd/Ni seeds exhibited more ACC deaminase activity and production of siderophores and IAA, while endophytes from control seeds, very surprisingly, showed more metal tolerance. Finally, the 3 most promising seed endophytes were selected based on their metal tolerance and plant growth promoting potential, and inoculated in Agrostis capillaris seedlings. In case of non-exposed plants, inoculation resulted in a significantly improved plant growth; after inoculation of Cd-exposed plants an increased Cd uptake was achieved without affecting plant growth. This indicates that inoculation of Agrostis with its seed endophytes might be beneficial for its establishment during phytoextraction and phytostabilisation of Cd-contaminated soils. PMID:24933875

  14. Exposure to soil, house dust and decaying plants increases gut microbial diversity and decreases serum immunoglobulin E levels in BALB/c mice.

    PubMed

    Zhou, Dongrui; Zhang, Honglin; Bai, Zhimao; Zhang, Aidi; Bai, Futian; Luo, Xing; Hou, Yue; Ding, Xiao; Sun, Beili; Sun, Xiao; Ma, Ning; Wang, Cuifen; Dai, Xiaoniu; Lu, Zuhong

    2016-05-01

    To assess the impact of sanitation of a living environment on gut microbiota and development of the immune system, we raised BALB/c mice under three distinct environmental conditions: a specific pathogen-free animal room (SPF), a general animal room (XZ) and a farmhouse (JD). All other variables like diet, age, genetic background, physiological status and original gut microbiota were controlled for in the three groups. Using high-throughput sequencing of the 16S rRNA gene, we found that each mouse group had a specific structure of the gut microbial community. Groups JD and XZ harboured a significantly more diverse and richer gut microbiota than did group SPF. Bacteroidetes were significantly more abundant in groups XZ and JD than in group SPF, whereas Firmicutes showed the inverse pattern. Total serum immunoglobulin E (IgE) levels were significantly lower in groups XZ and JD than in group SPF. There were no significant differences in gut microbiota diversity and serum IgE concentration between groups JD and XZ, but we found higher abundance of dominant genera in the gut microflora of group JD. We conclude that exposure to soil, house dust and decaying plant material enhances gut microbial diversity and innate immunity. Our results seem to provide new evidence supporting the hygiene hypothesis. PMID:25958920

  15. A direct correlation among indoor Rn, soil gas Rn and geology in the Reading Prong near Boyertown, Pennsylvania

    USGS Publications Warehouse

    Reimer, G.M.; Gundersen, L.C.S.

    1989-01-01

    We feel that this study suggests a relationship among geology, soil gas Rn and the potential for indoor Rn accumulation in this portion of the Reading Prong. There are deviations from a perfect correlation but these are related to inhomogeneities in the geologic environment and perhaps variations in construction techniques of homes in the area. This study also demonstrates that several analyses in a small area may be necessary to adequately determine the Rn distribution for a particular geologic unit. That scale would be determined by the complexity of the local geology. Where no discrete source of elevated Rn supply is found for dwellings having a significant Rn accumulation, the implication is that overall gross permeability may be sufficient to supply Rn from a larger volume of soil and rock.

  16. Towards Direct Numerical Simulation of mass and energy fluxes at the soil-atmospheric interface with advanced Lattice Boltzmann methods

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Krafczyk, Manfred; Geier, Martin; Schönherr, Martin

    2014-05-01

    The quantification of soil evaporation and of soil water content dynamics near the soil surface are critical in the physics of land-surface processes on many scales and are dominated by multi-component and multi-phase mass and energy fluxes between the ground and the atmosphere. Although it is widely recognized that both liquid and gaseous water movement are fundamental factors in the quantification of soil heat flux and surface evaporation, their computation has only started to be taken into account using simplified macroscopic models. As the flow field over the soil can be safely considered as turbulent, it would be natural to study the detailed transient flow dynamics by means of Large Eddy Simulation (LES [1]) where the three-dimensional flow field is resolved down to the laminar sub-layer. Yet this requires very fine resolved meshes allowing a grid resolution of at least one order of magnitude below the typical grain diameter of the soil under consideration. In order to gain reliable turbulence statistics, up to several hundred eddy turnover times have to be simulated which adds up to several seconds of real time. Yet, the time scale of the receding saturated water front dynamics in the soil is on the order of hours. Thus we are faced with the task of solving a transient turbulent flow problem including the advection-diffusion of water vapour over the soil-atmospheric interface represented by a realistic tomographic reconstruction of a real porous medium taken from laboratory probes. Our flow solver is based on the Lattice Boltzmann method (LBM) [2] which has been extended by a Cumulant approach similar to the one described in [3,4] to minimize the spurious coupling between the degrees of freedom in previous LBM approaches and can be used as an implicit LES turbulence model due to its low numerical dissipation and increased stability at high Reynolds numbers. The kernel has been integrated into the research code Virtualfluids [5] and delivers up to 30% of the

  17. Response analysis of a nuclear containment structure with nonlinear soil-structure interaction under bi-directional ground motion

    NASA Astrophysics Data System (ADS)

    Kumar, Santosh; Raychowdhury, Prishati; Gundlapalli, Prabhakar

    2015-06-01

    Design of critical facilities such as nuclear power plant requires an accurate and precise evaluation of seismic demands, as any failure of these facilities poses immense threat to the community. Design complexity of these structures reinforces the necessity of a robust 3D modeling and analysis of the structure and the soil-foundation interface. Moreover, it is important to consider the multiple components of ground motion during time history analysis for a realistic simulation. Present study is focused on investigating the seismic response of a nuclear containment structure considering nonlinear Winkler-based approach to model the soil-foundation interface using a distributed array of inelastic springs, dashpots and gap elements. It is observed from this study that the natural period of the structure increases about 10 %, whereas the force demands decreases up to 24 % by considering the soil-structure interaction. Further, it is observed that foundation deformations, such as rotation and sliding are affected by the embedment ratio, indicating an increase of up to 56 % in these responses for a reduction of embedment from 0.5 to 0.05× the width of the footing.

  18. Direct/delayed response project: Quality-assurance plan for preparation and analysis of soils from the mid-Appalachian region of the United States

    SciTech Connect

    Papp, M.L.; Van Remortel, R.D.; Palmer, C.J.; Byers, G.E.; Schumacher, B.A.

    1989-10-01

    The Direct/Delayed Response Project is designed to address the concern over potential acidification of surface waters by atmospheric sulfur deposition within the United States. The Mid-Appalachian Soil Survey is being conducted as a synoptic physical and chemical survey to characterize a statistical sampling of watersheds in a region of the United States believed to be susceptible to the effects of acidic deposition. The survey has benefitted from information gained during two previous, similar surveys. The documentation addresses the design and implementation of a quality-assurance program and the verification of the analytical data base for the Mid-Appalachian Soil Survey. It is addressed primarily to the users of the data base who will be analyzing the data and making various assessments and conclusions relating to the effects of acidic deposition on the soils of the Mid-Appalachian region, the third and final region characterized during the project. Data quality is assessed by addressing detectability, precision, accuracy, representativeness, completeness, and comparability of the data.

  19. Effect Of Soil Properties On The Geochemical Speciation Of Arsenic In Contaminated Soils: A Greenhouse Study

    NASA Astrophysics Data System (ADS)

    Sharma, S.; Sarkar, D.; Datta, R.

    2005-05-01

    Land-applied arsenical pesticides have contributed elevated soil arsenic (As) levels. Many baseline risk assessments As-contaminated sites assume that all As present in the soil is bioavailable, thereby potentially overestimating the actual health risk. However, risk from As exposure is associated only with those forms of As that are potentially extractable by the human gastrointestinal juices. It has been demonstrated that As may exist in several geochemical forms depending on soil chemical properties, which may or may not be bioavailable. The current study aims at addressing the issue of soil variability on As bioavailability as a function of soil physico-chemical properties in a greenhouse setting involving dynamic interactions between soil, water and plants. Four different soils were chosen based on their potential differences with respect to As reactivity: Immokalee, an acid sand with low extractable Fe/Al, having minimal arsenic retention capacity; Millhopper, an acid sandy loam with high extractable Fe/Al oxides; Pahokee Muck soil with 85% soil organic matter (SOM) as well as high Fe/Al content; and Orelia soil with high clay and Fe/Al content. Soils were amended with sodium arsenate (675 and 1500 mg/Kg). Rice (Oryza sativa) was used as the test crop. A sequential extraction scheme was employed to identify the geochemical forms of As in soils (soluble, exchangeable, organic, Fe/Al-bound, Ca/Mg-bound, residual) immediately after spiking; after 3 mo; and after 6 mo of equilibration time. Concentrations of these As forms were correlated with the in-vitro bioavailable As fractions to identify those As fractions that are most likely to be bioavailable. Results from this study showed that there was little to no plant growth in the contaminated soils. Sequential extractions of the soil indicated that arsenic is strongly adsorbed onto soil amorphous iron/aluminum oxides, and the degree of arsenic retention is a direct function of equilibration time.

  20. Proteomic screening identifies calreticulin as a miR-27a direct target repressing MHC class I cell surface exposure in colorectal cancer

    PubMed Central

    Colangelo, T; Polcaro, G; Ziccardi, P; Pucci, B; Muccillo, L; Galgani, M; Fucci, A; Milone, M R; Budillon, A; Santopaolo, M; Votino, C; Pancione, M; Piepoli, A; Mazzoccoli, G; Binaschi, M; Bigioni, M; Maggi, C A; Fassan, M; Laudanna, C; Matarese, G; Sabatino, L; Colantuoni, V

    2016-01-01

    Impairment of the immune response and aberrant expression of microRNAs are emerging hallmarks of tumour initiation/progression, in addition to driver gene mutations and epigenetic modifications. We performed a preliminary survey of independent adenoma and colorectal cancer (CRC) miRnoma data sets and, among the most dysregulated miRNAs, we selected miR-27a and disclosed that it is already upregulated in adenoma and further increases during the evolution to adenocarcinoma. To identify novel genes and pathways regulated by this miRNA, we employed a differential 2DE-DIGE proteome analysis. We showed that miR-27a modulates a group of proteins involved in MHC class I cell surface exposure and, mechanistically, demonstrated that calreticulin is a miR-27a direct target responsible for most downstream effects in epistasis experiments. In vitro miR-27a affected cell proliferation and angiogenesis; mouse xenografts of human CRC cell lines expressing different miR-27a levels confirmed the protein variations and recapitulated the cell growth and apoptosis effects. In vivo miR-27a inversely correlated with MHC class I molecules and calreticulin expression, CD8+ T cells infiltration and cytotoxic activity (LAMP-1 exposure and perforin release). Tumours with high miR-27a, low calreticulin and CD8+ T cells' infiltration were associated with distant metastasis and poor prognosis. Our data demonstrate that miR-27a acts as an oncomiRNA, represses MHC class I expression through calreticulin downregulation and affects tumour progression. These results may pave the way for better diagnosis, patient stratification and novel therapeutic approaches. PMID:26913609

  1. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops.

    PubMed

    Verbyla, M E; Iriarte, M M; Mercado Guzmán, A; Coronado, O; Almanza, M; Mihelcic, J R

    2016-05-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1mLg(-1) for coliphage, between 1 and 100mLg(-1) for Giardia and Cryptosporidium, and between 100 and 1000mLg(-1) for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda. PMID:26881733

  2. PCNs (polychlorinated napthalenes): dietary exposure via cereal crops, distribution and screening-level risk assessment in wheat, rice, soil and air along two tributaries of the River Chenab, Pakistan.

    PubMed

    Mahmood, Adeel; Malik, Riffat Naseem; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-05-15

    There is a lack of scientific literature regarding the bioaccumulation, dietary and toxicity exposure of PCN via food crops. The current study presents the information of dietary intake, distribution pattern and screening level risk assessment of PCN in wheat, rice, soil and air along upstream feeding tributaries of the River Chenab, Punjab Province, Pakistan. A total six air and twenty eight of soil, wheat and rice samples were collected during Jan, 2013 to June, 2013 to analyze the thirty nine PCN congeners. ∑39PCN concentrations were ranged between 0.02 and 0.21 ng g(-1) dw, 0.02-1.21 ng g(-1) dw, 24.6-233 ng g(-1) dw and 1,222-5,052 pg m(-3) in wheat, rice, soil and air samples, respectively. In this study soil exhibited higher TEQ values while in case of air, wheat and rice TEQ concentrations were in accordance with the previously reported pattern from other parts of the world. Estimated daily intake (EDI) of ∑39PCN through consumption of wheat and rice was estimated as 0.21 ng kg(-1) (body weight)day(-1) and 0.03 ng kg(-1) (body weight)day(-1), respectively. This is the first report of PCN dietary intake and screening-level risk assessment by consumption of cereal crops from Pakistan. The results of dietary and toxicity exposure of PCN warrant auxiliary devotion in future, to this group of contaminant. PMID:24607633

  3. Assessment of ambient gamma dose rate around a prospective uranium mining area of South India - A comparative study of dose by direct methods and soil radioactivity measurements

    NASA Astrophysics Data System (ADS)

    Karunakara, N.; Yashodhara, I.; Sudeep Kumara, K.; Tripathi, R. M.; Menon, S. N.; Kadam, S.; Chougaonkar, M. P.

    Indoor and outdoor gamma dose rates were evaluated around a prospective uranium mining region - Gogi, South India through (i) direct measurements using a GM based gamma dose survey meter, (ii) integrated measurement days using CaSO4:Dy based thermo luminescent dosimeters (TLDs), and (iii) analyses of 273 soil samples for 226Ra, 232Th, and 40K activity concentration using HPGe gamma spectrometry. The geometric mean values of indoor and outdoor gamma dose rates were 104 nGy h-1 and 97 nGy h-1, respectively with an indoor to outdoor dose ratio of 1.09. The gamma dose rates and activity concentrations of 226Ra, 232Th, and 40K varied significantly within a small area due to the highly localized mineralization of the elements. Correlation study showed that the dose estimated from the soil radioactivity is better correlated with that measured directly using the portable survey meter, when compared to that obtained from TLDs. This study showed that in a region having localized mineralization in situ measurements using dose survey meter provide better representative values of gamma dose rates.

  4. Exposure pathway evaluations for sites that processed asbestos-contaminated vermiculite.

    PubMed

    Anderson, Barbara A; Dearwent, Steve M; Durant, James T; Dyken, Jill J; Freed, Jennifer A; Moore, Susan McAfee; Wheeler, John S

    2005-01-01

    The Agency for Toxic Substances and Disease Registry (ATSDR) is currently evaluating the potential public health impacts associated with the processing of asbestos-contaminated vermiculite at various facilities around the country. Vermiculite ore contaminated with significant levels of asbestos was mined and milled in Libby, Montana, from the early 1920s until 1990. The majority of the Libby ore was then shipped to processing facilities for exfoliation. ATSDR initiated the National Asbestos Exposure Review (NAER) to identify and evaluate exposure pathways associated with these processing facilities. This manuscript details ATSDR's phased approach in addressing exposure potential around these sites. As this is an ongoing project, only the results from a selected set of completed site analyses are presented. Historical occupational exposures are the most significant exposure pathway for the site evaluations completed to date. Former workers also probably brought asbestos fibers home on their clothing, shoes, and hair, and their household contacts may have been exposed. Currently, most site-related worker and community exposure pathways have been eliminated. One community exposure pathway of indeterminate significance is the current exposure of individuals through direct contact with waste rock brought home for personal use as fill material, driveway surfacing, or soil amendment. Trace levels of asbestos are present in soil at many of the sites and buried waste rock has been discovered at a few sites; therefore, future worker and community exposure associated with disturbing on-site soil during construction or redevelopment at these sites is also a potential exposure pathway. PMID:15881979

  5. Risk-based ecological soil quality criteria for the characterization of contaminated soils. Combination of chemical and biological tools.

    PubMed

    Fernández, María Dolores; Vega, María Milagrosa; Tarazona, José Vicente

    2006-08-01

    This paper describes the development of soil quality criteria for the characterization of soils focused on the potential risk to the ecosystem. The approach combines both Generic Soil Quality standards (GSQs) for individual chemicals and direct ecotoxicity assays on soil samples taken from the site. Criteria establish three main risk levels with their corresponding trigger values. The trigger values to determine high risk or "polluted" soils are exclusively based on direct toxicity assessments. The trigger values for the other categories are established by a combination of the application of GSQs and the results of bioassays. Low-risk is assumed when no toxicity is observed and GSQs based on precautionary ecotoxicity thresholds are not exceeded; high-risk must be considered if acute toxicity above the proposed trigger value is observed in soil or leachate samples. In between these levels, the risk cannot be elucidated and a site-specific assessment is required. The GSQs take into account the current or future land use, thus defining three categories: industrial soils, urban/residential soils and natural/agricultural/forest soils, each of them with different ecological requirements. The GSQ values are established following an inverse risk assessment methodology, integrating ecotoxicity and exposure models and setting the soil levels associated to pre-established criteria for the assumption of low risk. The proposed methodology covers all relevant ecological receptors and processes, soil organisms, potential contamination of ground and surface waters, and exposure of terrestrial vertebrates due to bioaccumulation and biomagnification. Exposure routes and protection criteria are defined in each protection goal. The relevance of each receptor and route is established according to the land use. PMID:16574196

  6. Ground Thermal Diffusivity Calculation by Direct Soil Temperature Measurement. Application to very Low Enthalpy Geothermal Energy Systems.

    PubMed

    Andújar Márquez, José Manuel; Martínez Bohórquez, Miguel Ángel; Gómez Melgar, Sergio

    2016-01-01

    This paper presents a methodology and instrumentation system for the indirect measurement of the thermal diffusivity of a soil at a given depth from measuring its temperature at that depth. The development has been carried out considering its application to the design and sizing of very low enthalpy geothermal energy (VLEGE) systems, but it can has many other applications, for example in construction, agriculture or biology. The methodology is simple and inexpensive because it can take advantage of the prescriptive geotechnical drilling prior to the construction of a house or building, to take at the same time temperature measurements that will allow get the actual temperature and ground thermal diffusivity to the depth of interest. The methodology and developed system have been tested and used in the design of a VLEGE facility for a chalet with basement at the outskirts of Huelva (a city in the southwest of Spain). Experimental results validate the proposed approach. PMID:26938534

  7. Ground Thermal Diffusivity Calculation by Direct Soil Temperature Measurement. Application to very Low Enthalpy Geothermal Energy Systems

    PubMed Central

    Andújar Márquez, José Manuel; Martínez Bohórquez, Miguel Ángel; Gómez Melgar, Sergio

    2016-01-01

    This paper presents a methodology and instrumentation system for the indirect measurement of the thermal diffusivity of a soil at a given depth from measuring its temperature at that depth. The development has been carried out considering its application to the design and sizing of very low enthalpy geothermal energy (VLEGE) systems, but it can has many other applications, for example in construction, agriculture or biology. The methodology is simple and inexpensive because it can take advantage of the prescriptive geotechnical drilling prior to the construction of a house or building, to take at the same time temperature measurements that will allow get the actual temperature and ground thermal diffusivity to the depth of interest. The methodology and developed system have been tested and used in the design of a VLEGE facility for a chalet with basement at the outskirts of Huelva (a city in the southwest of Spain). Experimental results validate the proposed approach. PMID:26938534

  8. Biomedical HIV prevention including pre-exposure prophylaxis and opiate agonist therapy for women who inject drugs: State of research and future directions

    PubMed Central

    Page, Kimberly; Tsui, Judith; Maher, Lisa; Choopanya, Kachit; Vanichseni, Suphak; Mock, Philip A.; Celum, Connie; Martin, Michael

    2015-01-01

    Women who inject drugs are at higher risk of HIV compared to their male counterparts as a result of multiple factors including biological, behavioral and socio-structural, yet comparatively little effort has been invested in testing and delivering prevention methods that directly target this group. In this paper, we discuss the need for expanded prevention interventions for women who inject drugs, focusing on two safe, effective, and approved, yet underutilized biomedical prevention methods: opiate agonist therapy (OAT) and oral pre-exposure prophylaxis (PrEP). While both interventions are well researched they have not been well examined in the context of gender. We discuss the drivers of women injectors’ higher HIV risk, review the effectiveness of OAT and PrEP interventions among women, and explain why these new HIV prevention tools should be prioritized for women who inject drugs. There is substantial potential for impact of OAT and PrEP programs for women who inject drugs in the context of broader gender-responsive HIV prevention initiatives. While awaiting efficacy data on other biomedical approaches in the HIV prevention research ‘pipeline’, we propose that the scale up and implementation of these proven, safe, and effective interventions are needed now. PMID:25978484

  9. The Impact of Risk Information Exposure on Women’s Beliefs about Direct-to-Consumer Genetic Testing for BRCA Mutations

    PubMed Central

    Gray, Stacy W.; Hornik, Robert C.; Schwartz, J. Sanford; Armstrong, Katrina

    2011-01-01

    Despite an increase in direct-to-consumer (DTC) genetic testing, little is known about how variations in website content might alter consumer behavior. We evaluated the impact of risk information provision on women’s attitudes about DTC BRCA testing. We conducted a randomized experiment; women viewed a “mock” BRCA testing website without (control group: CG) or with information on the potential risks of DTC testing (RG; framed two ways: unattributed information [UR] and information presented by experts [ER]). 767 women participated; mean age was 37 years, mean education was 15 years, and 79% of subjects were white. Women in the RG had less positive beliefs about DTC testing (mean RG=23.8, CG=25.2; p=0.001), lower intentions to get tested (RG= 2.8, CG= 3.1; p=0.03), were more likely to prefer clinic-based testing (RG=5.1, CG=4.8; p=0.03) and to report that they had seen enough risk information (RG=5.3, CG= 4.7; p<0.001). UR and ER exposure produced similar effects. Effects did not differ for women with or without a personal/family history of breast/ovarian cancer. Exposing women to the potential risks of DTC BRCA testing altered their beliefs, preferences, and intentions. Risk messages appear to be salient to women irrespective of their chance of having a BRCA mutation. PMID:21992449

  10. Characterization of surface soils at a former uranium mill.

    PubMed

    Johnson, J A; Meyer, H R; Vidyasagar, M

    2006-02-01

    Dawn Mining Company operated a uranium mill in Stevens County, Washington, from 1957 to 1982, to process ore from the Midnite Mine, and from 1992 through 2000, to extract uranium from mine water treatment sludge. The mill was permanently shut down in 2001 when the Dawn Mining Company radioactive materials license was amended to allow direct disposal of water treatment sludge to a tailings disposal area at the mill. The mill building was demolished in 2003. Site soil characterization took place in 2004. Soil cleanup is ongoing. Contaminated soils on the site were characterized using a GPS-based gamma scanning system. A correlation between shielded gamma exposure rate and concentration of Ra in surface soils was developed. Subsurface soils were sampled using backhoe trenches. This system proved efficient and accurate in guiding development of the remedial action planning for the site and subsequent soil cleanup. PMID:16404186

  11. An Analysis of the Effects of Vancomycin and/or Vancomycin-Resistant Citrobacter freundii Exposure on the Microbial Community Structure in Soil.

    PubMed

    Cycoń, Mariusz; Borymski, Sławomir; Orlewska, Kamila; Wąsik, Tomasz J; Piotrowska-Seget, Zofia

    2016-01-01

    The occurrence of antibiotics and antibiotic resistance genes in the environment has become a subject of growing concern. The extensive use of vancomycin and other pharmaceuticals may alter the biodiversity of soil microbial communities and select antibiotic-resistant bacteria. Therefore, the purpose of the study was to evaluate the impact of vancomycin and/or vancomycin-resistant Citrobacter freundii on soil microbial communities using the denaturing gradient gel electrophoresis (DGGE) and the phospholipid fatty acid (PLFA) approaches. The experiment had a completely randomized block design with the following treatments: control soil (C), soil with vancomycin (1 mg/kg soil-VA1), soil with vancomycin (10 mg/kg soil-VA10), soil with C. freundii (Cit), soil with vancomycin (1 mg/kg soil) and C. freundii (VA1+Cit), and soil with vancomycin (10 mg/kg soil) and C. freundii (VA10+Cit). A bacterial strain resistant to vancomycin was isolated from raw sewage collected from the municipal sewage treatment plant. The obtained results indicated that the antibiotic and/or the bacterial strain exerted a selective pressure that resulted in qualitative and quantitative changes in the population of soil microorganisms. However, a multivariate analysis showed that the genetic and structural diversity of the soil microbial community was primarily affected by the incubation time and to a lesser extent by the antibiotic and introduced bacteria. DGGE analysis clearly showed that certain species within the bacterial community were sensitive to vancomycin as was evidenced by a decrease in the values of S (richness) and H (Shannon-Wiener) indices. Moreover, a PLFA method-based analysis revealed alterations in the structure of the soil microbial community as indicated by changes in the biomass of the PLFA biomarkers specific for Gram-positive and Gram-negative bacteria as well as fungi. The changes observed in the community of soil microorganisms may decrease the rate of microbial

  12. Mapping Soil Water-Holding Capacity Index to Evaluate the Effectiveness of Phytoremediation Protocols and ExposureRisk to Contaminated Soils in a National Interest Priority Site of the Campania Region (Southern Italy).

    NASA Astrophysics Data System (ADS)

    Romano, N.

    2015-12-01

    Soil moisture is an important state variable that influences water flow and solute transport in the soil-vegetation-atmosphere system, and plays a key role in securing agricultural ecosystem services for nutrition and food security. Especially when environmental studies should be carried out at relatively large spatial scales, there is a need to synthesize the complex interactions between soil, plant behavior, and local atmospheric conditions. Although it relies on the somewhat loosely defined concepts of "field capacity" and "wilting point", the soil water-holding capacity seems a suitable indicator to meet the above-mentioned requirement, yet easily understandable by the public and stakeholders. This parameter is employed in this work to evaluate the effectiveness of phytoremediation protocols funded by the EU-Life project EcoRemed and being implemented to remediate and restore contaminated agricultural soils of the National Interest Priority Site Litorale Domizio-Agro Aversano. The study area is located in the Campania Region (Southern Italy) and has an extent of about 200,000 hectares. A high-level spotted soil contamination is mostly due to the legal or outlaw industrial and municipal wastes, with hazardous consequences also on groundwater quality. With the availability of soil and land systems maps for this study area, disturbed and undisturbed soil samples were collected at two different soil depths to determine basic soil physico-chemical properties for the subsequent application of pedotransfer functions (PTFs). Soil water retention and hydraulic conductivity functions were determined for a number of soil cores, in the laboratory with the evaporation experiments, and used to calibrate the PTFs. Efficient mapping of the soil hydraulic properties benefitted greatly from the use of the PTFs and the physically-based scaling procedure developed by Nasta et al. (2013, WRR, 49:4219-4229).

  13. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN SOIL AND SEDIMENT MILESTONE INC.'S DIRECT MERCURY ANALYZER (DMA)-80

    EPA Science Inventory

    Milestone's Direct Mercury Analyzer (DMA-80) was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003 at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to...

  14. CORRELATING METAL SPECIATION IN SOILS

    EPA Science Inventory

    Understanding bioavailability of metals from exposure to contaminated soils is a challenging aspect of environmental research. This presentation will examine three areas of research with respect to metal speciation in soils as it relates to bioavailability: 1) Pb immobilization a...

  15. Exposure chamber

    DOEpatents

    Moss, Owen R.; Briant, James K.

    1983-01-01

    An exposure chamber includes an imperforate casing having a fluid inlet at the top and an outlet at the bottom. A single vertical series of imperforate trays is provided. Each tray is spaced on all sides from the chamber walls. Baffles adjacent some of the trays restrict and direct the flow to give partial flow back and forth across the chambers and downward flow past the lowermost pan adjacent a central plane of the chamber.

  16. Community assembly of biological soil crusts of different successional stages in a temperate sand ecosystem, as assessed by direct determination and enrichment techniques.

    PubMed

    Langhans, Tanja Margrit; Storm, Christian; Schwabe, Angelika

    2009-08-01

    In temperate regions, biological soil crusts (BSCs: complex communities of cyanobacteria, eukaryotic algae, bryophytes, and lichens) are not well investigated regarding community structure and diversity. Furthermore, studies on succession are rare. For that reason, the community assembly of crusts representing two successional stages (initial, 5 years old; and stable, >20 years old) were analyzed in an inland sand ecosystem in Germany in a plot-based approach (2 x 18 plots, each 20 x 20 cm). Two different methods were used to record the cyanobacteria and eukaryotic algae in these communities comprehensively: determination directly out of the soil and enrichment culture techniques. Additionally, lichens, bryophytes, and phanerogams were determined. We examine four hypotheses: (1) A combination of direct determination and enrichment culture technique is necessary to detect cyanobacteria and eukaryotic algae comprehensively. In total, 45 species of cyanobacteria and eukaryotic algae were detected in the study area with both techniques, including 26 eukaryotic algae and 19 cyanobacteria species. With both determination techniques, 22 identical taxa were detected (11 eukaryotic algae and 11 cyanobacteria). Thirteen taxa were only found by direct determination, and ten taxa were only found in enrichment cultures. Hence, the hypothesis is supported. Additionally, five lichen species (three genera), five bryophyte species (five genera), and 24 vascular plant species occurred. (2) There is a clear difference between the floristic structure of initial and stable crusts. The different successional stages are clearly separated by detrended correspondence analysis, showing a distinct structure of the community assembly in each stage. In the initial crusts, Klebsormidium flaccidum, Klebsormidium cf. klebsii, and Stichococcus bacillaris were important indicator species, whereas the stable crusts are especially characterized by Tortella inclinata. (3) The biodiversity of BSC taxa

  17. Short-term exposure to tumor necrosis factor-alpha enables human osteoblasts to direct adipose tissue-derived mesenchymal stem cells into osteogenic differentiation.

    PubMed

    Lu, ZuFu; Wang, Guocheng; Dunstan, Colin R; Zreiqat, Hala

    2012-09-01

    Tumor necrosis factor-alpha (TNF-α) is one major inflammatory factor peaking at 24 h after bone fracture in response to injury; its role in bone healing is controversial. The aims of this study were to investigate whether the duration of exposure to TNF-α is crucial for the initiation of bone regeneration and to determine its underlying mechanism(s). We demonstrated that 24 h of TNF-α treatment significantly abrogated osteocalcin gene expression by human primary osteoblasts (HOBs). However, when TNF-α was withdrawn after 24 h, bone sialoprotein and osteocalcin gene expression levels in HOBs at day 7 were significantly up-regulated compared with the HOBs without TNF-α treatment. In contrast, continuous TNF-α treatment down-regulated bone sialoprotein and osteocalcin gene expression. In addition, in an indirect co-culture system, HOBs pretreated with TNF-α for 24 h induced significantly greater osteogenic differentiation of adipose tissue-derived mesenchymal stem cells (ASCs) than the HOBs without TNF-α treatment. TNF-α treatment also promoted endogenous bone morphogenetic protein 2 (BMP-2) production in HOBs, while blocking the BMP-2 signaling pathway with Noggin inhibited osteogenic differentiation of ASCs in the co-culture system. Furthermore, activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway after TNF-α treatment occurred earlier than BMP-2 protein expression. BMP-2 production by HOBs and osteogenic differentiation of ASCs in the co-culture system with HOBs was significantly decreased when HOBs were pretreated with TNF-α in combination with the p38 MAPK-specific inhibitor (SB203580). Taken together, we provide evidence that exposure duration is a critical element in determining TNF-α's effects on bone regeneration. We also demonstrate that the p38 MAPK signaling pathway regulates the expression of BMP-2 in osteoblasts, which then acts through a paracrine loop, to direct the osteoblast lineage commitment of mesenchymal

  18. [Direct cloning of gene encoding a novel amylomaltase from soil bacterial DNA for large-ring cyclodextrin production].

    PubMed

    Sawasdee, K; Rudeekulthamrong, P; Zimmermann, W; Murakami, S; Pongsawasdi, P; Kaulpiboon, J

    2014-01-01

    The aim of this study was to isolate a novel amylomaltase gene from community DNA of soil samples collected from Ban Nong Khrok hot spring in Thailand without bacterial cultivation. Using PCR, a 1.5 kb full-length gene was amplified and ligated with pGEM-T easy vector to transform into Escherichia coli DH5 alpha for sequencing. The obtained gene encoding an amylomaltase consisted of 1.503 bp that translated into 500 amino acids. Amino acid sequence deduced from this gene was highly homologous with that of amylomaltase from Thermus thermophillus ATCC 33923. In order to express the enzyme, the cloned gene was subcloned into plasmid pET-17b and introduced into E. coli BL21 (DE3). The maximum expression was observed when the cloned cells were cultured at 37 degrees C for 6 h with 0.5 mM IPTG induction. By 10% SDS-PAGE, the relative molecular mass of the purified amylomaltase was approximately 58 kDa. This enzyme was optimally active at 70 degrees C and pH 9.0. In addition, the enzyme could hydrolyze pea starch to yield the large-ring cyclodextrins with degrees of polymerization of 23 and higher. It is noted that CD29 was the product in the largest quantity under all tested conditions. PMID:25272748

  19. Direct determination of arsenic in soil samples by fast pyrolysis-chemical vapor generation using sodium formate as a reductant followed by nondispersive atomic fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Duan, Xuchuan; Zhang, Jingya; Bu, Fanlong

    2015-09-01

    This new study shows for the first time that sodium formate can react with trace arsenic to form volatile species via fast pyrolysis - chemical vapor generation. We found that the presence of thiourea greatly enhanced the generation efficiency and eliminated the interference of copper. We studied the reaction temperature, the volume of sodium formate, the reaction acidity, and the carried argon rate using nondispersive atomic fluorescence spectrometry. Under optimal conditions of T = 500 °C, the volumes of 30% sodium formate and 10% thiourea were 0.2 ml and 0.05 ml, respectively. The carrier argon rate was 300 ml min- 1 and the detection limit and precision of arsenic were 0.39 ng and 3.25%, respectively. The amount of arsenic in soil can be directly determined by adding trace amount of hydrochloric acid as a decomposition reagent without any sample pretreatment. The method was successfully applied to determine trace amount of arsenic in two soil-certified reference materials (GBW07453 and GBW07450), and the results were found to be in agreement with certified reference values.

  20. Simultaneous determination of mercury and organic carbon in sediment and soils using a direct mercury analyzer based on thermal decomposition-atomic absorption spectrophotometry.

    PubMed

    Chen, Jingjing; Chakravarty, Pragya; Davidson, Gregg R; Wren, Daniel G; Locke, Martin A; Zhou, Ying; Brown, Garry; Cizdziel, James V

    2015-04-29

    The purpose of this work was to study the feasibility of using a direct mercury analyzer (DMA) to simultaneously determine mercury (Hg) and organic matter content in sediment and soils. Organic carbon was estimated by re-weighing the sample boats post analysis to obtain loss-on-ignition (LOI) data. The DMA-LOI results were statistically similar (p<0.05) to the conventional muffle furnace approach. A regression equation was developed to convert DMA-LOI data to total organic carbon (TOC), which varied between 0.2% and 13.0%. Thus, mercury analyzers based on combustion can provide accurate estimates of organic carbon content in non-calcareous sediment and soils; however, weight gain from moisture (post-analysis), measurement uncertainty, and sample representativeness should all be taken into account. Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed. Wetland sediments generally had higher levels of Hg than open water areas owing to a greater fraction of fine particles and higher levels of organic matter. Annual loading of Hg in open water areas was estimated at 4.3, 13.4, 19.2, 20.7, 129, and 135 ng cm(-2) yr(-1) for Beasley, Roundaway, Hampton, Washington, Wolf and Sky Lakes, respectively. Generally, the interval with the highest Hg flux was dated to the 1960s and 1970s. PMID:25847156

  1. An Analysis of the Effects of Vancomycin and/or Vancomycin-Resistant Citrobacter freundii Exposure on the Microbial Community Structure in Soil

    PubMed Central

    Cycoń, Mariusz; Borymski, Sławomir; Orlewska, Kamila; Wąsik, Tomasz J.; Piotrowska-Seget, Zofia

    2016-01-01

    The occurrence of antibiotics and antibiotic resistance genes in the environment has become a subject of growing concern. The extensive use of vancomycin and other pharmaceuticals may alter the biodiversity of soil microbial communities and select antibiotic-resistant bacteria. Therefore, the purpose of the study was to evaluate the impact of vancomycin and/or vancomycin-resistant Citrobacter freundii on soil microbial communities using the denaturing gradient gel electrophoresis (DGGE) and the phospholipid fatty acid (PLFA) approaches. The experiment had a completely randomized block design with the following treatments: control soil (C), soil with vancomycin (1 mg/kg soil—VA1), soil with vancomycin (10 mg/kg soil—VA10), soil with C. freundii (Cit), soil with vancomycin (1 mg/kg soil) and C. freundii (VA1+Cit), and soil with vancomycin (10 mg/kg soil) and C. freundii (VA10+Cit). A bacterial strain resistant to vancomycin was isolated from raw sewage collected from the municipal sewage treatment plant. The obtained results indicated that the antibiotic and/or the bacterial strain exerted a selective pressure that resulted in qualitative and quantitative changes in the population of soil microorganisms. However, a multivariate analysis showed that the genetic and structural diversity of the soil microbial community was primarily affected by the incubation time and to a lesser extent by the antibiotic and introduced bacteria. DGGE analysis clearly showed that certain species within the bacterial community were sensitive to vancomycin as was evidenced by a decrease in the values of S (richness) and H (Shannon-Wiener) indices. Moreover, a PLFA method-based analysis revealed alterations in the structure of the soil microbial community as indicated by changes in the biomass of the PLFA biomarkers specific for Gram-positive and Gram-negative bacteria as well as fungi. The changes observed in the community of soil microorganisms may decrease the rate of microbial

  2. Exposure assessment of trichloroethylene.

    PubMed Central

    Wu, C; Schaum, J

    2000-01-01

    This article reviews exposure information available for trichloroethylene (TCE) and assesses the magnitude of human exposure. The primary sources releasing TCE into the environment are metal cleaning and degreasing operations. Releases occur into all media but mostly into the air due to its volatility. It is also moderately soluble in water and can leach from soils into groundwater. TCE has commonly been found in ambient air, surface water, and groundwaters. The 1998 air levels in microg/m(3) across 115 monitors can be summarized as follows: range = 0.01-3.9, mean = 0.88. A California survey of large water utilities in 1984 found a median concentration of 3.0 microg/L. General population exposure to TCE occurs primarily by inhalation and water ingestion. Typical average daily intakes have been estimated as 11-33 microg/day for inhalation and 2-20 microg/day for ingestion. A small portion of the population is expected to have elevated exposures as a result of one or more of these pathways: inhalation exposures to workers involved in degreasing operations, ingestion and inhalation exposures occurring in homes with private wells located near disposal/contamination sites, and inhalation exposures to consumers using TCE products in areas of poor ventilation. More current and more extensive data on TCE levels in indoor air, water, and soil are needed to better characterize the distribution of background exposures in the general population and elevated exposures in special subpopulations. Images Figure 1 PMID:10807565

  3. Research on the Influence of Excavation and Loading on Z-Direction Displacement in Surrounding Soil Mass

    NASA Astrophysics Data System (ADS)

    Li, X.; Zhou, W.; Han, L.; Xi, W. J.; Crusoe, Garmondyu E.

    2014-12-01

    To probe into the pattern in which the excavation and loading process have on such factors as stress and displacement in neighboring regions of deep open pits, a mechanical unloading model in coal mining process and another model for the loading process are set up respectively. Besides, FLAC3D software is used to simulate dynamic excavating and loading process in open pits and record such data as the unbalanced stress, unloading strength and displacement fluctuations, which further serve as basis for studying the functional relationship about different mining heights and scope of influence using fitting method. The research results indicate that the unloading strength enhances with increasing mining depth in a linear fashion. In addition, a noticeable displacement circle takes shape around the stope, which would also extends with growing mining depth. As to waste loading, it brings about large-scale surface subsidence in neighboring regions, which follows a logarithm function convergence pattern with the distance away from the dump border. Under combined effects of excavation and loading, the value of the soil mass displacement would increase with growing mining depth and loading height. Specifically, the soil displacement at a distance of 100 m away from the stope border (around 200 m away from the outer dump border) is abnormally significant and it further develops at a rate of 0.0228 mm/h. W celu zbadania zależności pomiędzy procesami wydobycia i składowania urobku a takimi czynnikami jak naprężenia i przemieszczenia w sąsiadujących partiach głębokich wyrobisk odkrywkowych, wykorzystano model mechaniczny procesu urabiania węgla oraz model procesu jego składowania. Wykorzystano oprogramowanie FLAC 3D do symulacji procesów wydobycia i składowania w wyrobiskach odkrywkowych, zapisano odpowiednie dane: niezrównoważone naprężenia, wytrzymałość w trakcie odciążania oraz wahania przemieszczeń gruntu, które wykorzystane zostały następnie jako

  4. Surface-atmosphere interactions and convection triggering in the Nam Co Lake basin, Tibetan Plateau: Influence of soil moisture and wind direction

    NASA Astrophysics Data System (ADS)

    Gerken, T.; Biermann, T.; Babel, W.; Herzog, M.; Ma, Y.; Foken, T.; Graf, H.

    2013-12-01

    Surface-atmosphere interactions through the exchange of momentum, energy and water play a crucial role in the development of mesoscale circulations, clouds and convection, which in turn feed back to the surface. Atmospheric circulations modeling frameworks commonly have a too coarse resolution in order to fully capture these interactions. We use the cloud-resolving Active Tracer High-resolution Atmospheric Model (ATHAM) which is developed and used for mescoscale applications, in order to investigate the interactions between the surface and the atmosphere in a lake-land-atmosphere system on the Tibetan Plateau. Nam Co Lake, at 4730 m altitude, is surrounded by alpine steppe grassland and mountain chains. During the summer monsoon season there is a high variability of soil moisture with Bowen-ratios ranging from 0.5 to 3. Local water recycling is important. We identified two different mechanisms for convection triggering in the lake system that are dependent on the direction of the background wind: Triggering over topography, when the background wind and the lake-breeze have the same flow direction and triggering due to convergence between the lake-breeze front and the background wind. The type of convection triggering determines whether precipitation will occur within the basin. We will also present modeling studies investigating the impact of soil moisture in the generation of mesoscale circulations between the lake and the land surface and will show how the surface influences the evolution from boundary-layer clouds to moist convection. Additionally, the influence of clouds on the surface energy-balance is discussed.

  5. Experimental infection of calves, sheep, goats and pigs with HoBi-like viruses by direct inoculation or exposure to persistently infected calves.

    PubMed

    Bauermann, F V; Falkenberg, S M; Decaro, N; Flores, E F; Ridpath, J F

    2015-12-31

    HoBi-like viruses are an emerging species of pestiviruses associated with respiratory and reproductive disease in cattle and in water buffaloes. Although cattle appear to be the main natural hosts, little is know about the potential for HoBi-like viruses to be transmitted to other livestock. In this study, seronegative calves, goats and pigs, and sheep harboring pestivirus antibodies (probably due to previous exposure to BVDV) were exposed to HoBi-like viruses either by direct inoculation (GIn) or by contact with calves persistently infected with HoBi-like viruses (GEx). Both GIn and GEx groups were monitored for clinical signs, lymphocyte count, virus in buffy coats and nasal swabs up to day 18 post-inoculation (pi). Evidence of transmission of HoBi-like virus by PI calves was observed in all studied species. No difference in clinical presentation was observed between animals in the GIn or GEx groups. Evidence of infection, depending on the species included lymphocyte depletion, fever, viral RNA detection, and/or seroconversion. Depletion of lymphocytes was observed in calves and goats (35% and 50%, respectively) but not in pigs. Seroconversion was observed in at least one animal of each group and for all exposed species. The rate of seroconversion was higher in animals in the GIn experimental groups. In sheep, pre-existing moderate to high neutralizing titers against BVDV did not prevent viral replication and shed. The study demonstrated that naive cattle, goats and pigs, in addition to antibody positive sheep, can be infected by HoBi-like virus via persistently infected calf and potentially transmit the virus. PMID:26525738

  6. Direct exposure of mouse ovaries and oocytes to high doses of an adenovirus gene therapy vector fails to lead to germ cell transduction.

    PubMed

    Gordon, J W

    2001-04-01

    The risk of insertion of adenovirus gene therapy DNA into female germ cells during the course of somatic gene therapy was stringently tested in the mouse by injecting up to 10(10) infectious particles directly into the ovary and by incubating naked oocytes in a solution of 2 x 10(8) particles/ml for 1 h prior to in vitro fertilization (IVF). The vector used was a recombinant adenovirus carrying the bacterial lacZ gene driven by the cytomegalovirus promoter (Adbeta-gal). Ovaries were stained for LacZ activity, or immunochemically for LacZ, 5-7 days after injection. Although very large amounts of LacZ activity and protein were detected, all positive staining was in the thecal portion of the ovary, with no staining seen in oocytes. In another series of experiments, mice with injected ovaries were mated, and preimplantation embryos or fetuses were analyzed either for LacZ expression or by PCR for lacZ DNA. None of 202 preimplantation embryos stained positively for LacZ and none of 58 fetuses were positive for DNA by PCR analysis. Finally, more than 1400 eggs were fertilized after exposure to the vector prior to IVF and stained as morulae for LacZ activity. Fewer than 2% of the embryos stained positively for LacZ, and experiments indicated that the staining was due to incomplete washing of the eggs prior to IVF. These data provide strong evidence that adenoviruses cannot infect oocytes and that the risk of female germ-line transduction with such vectors is very low. PMID:11319918

  7. Evaluation of the protection elicited by direct and indirect exposure to live attenuated infectious laryngotracheitis virus vaccines against a recent challenge strain from the United States.

    PubMed

    Rodríguez-Avila, Andrés; Oldoni, Ivomar; Riblet, Sylva; Garcia, Maricarmen

    2008-06-01

    In a recent study (Oldoni & García, 2007), some field strains of infectious laryngotracheitis viruses (ILTV) were characterized as genotypically different (group VI) from ILT vaccine strains. The objective of this study was to evaluate the protection elicited by one chicken embryo origin (CEO) and one tissue culture origin (TCO) vaccine against a field isolate from group VI after direct and indirect exposure to ILTV live attenuated vaccines. In phase 1 of the experiment, non-vaccinated chickens were placed into contact with the eye drop vaccinates for a period of four weeks after vaccination. Transmission of the vaccine virus to these in-contact birds was demonstrated by real time PCR and antibody production, although the in-contact birds did not become protected against disease when subsequently challenged in phase 2 of the experiment. This emphasized the importance of uniform vaccination to obtain adequate protection, both to avoid the occurrence of susceptible chickens, and to minimize the potential for reversion to virulence of live-attenuated vaccines. In phase 2, protection against challenge with a group VI field virus was assessed four weeks after vaccination by scoring clinical signs and mortality, and quantifying weight gain. Sentinel birds were added to the groups one day after challenge to assess shedding of challenge virus, using real time PCR and virus isolation, during the period 2 to 12 days post challenge. The results showed that the CEO and TCO eye drop-vaccinated chickens were protected against challenge with the group VI virus, even though it was genetically different from the vaccine strains, and that challenge virus was not transmitted from these protected birds to the sentinels. PMID:18568655

  8. Chemical study of triterpenoid resinous materials in archaeological findings by means of direct exposure electron ionisation mass spectrometry and gas chromatography/mass spectrometry.

    PubMed

    Modugno, Francesca; Ribechini, Erika; Colombini, Maria Perla

    2006-01-01

    A systematic study of standard triterpenes (alpha-amyrine, oleanolic acid, betulin, lupeol, betulinic acid and lupenone) and of raw resinous materials (frankincense resin, mastic resin and birch bark pitch) was performed using direct exposure electron ionisation mass spectrometry (DE-MS) and gas chromatography/mass spectrometry (GC/MS). DE-MS provides a mass spectral fingerprint of organic materials in a few minutes which highlights the compounds that are the main components in the sample. The application of principal component analysis (PCA) on DE-MS data in the mass ranges m/z 181-260 and m/z 331-500, corresponding to the fragmentation of triterpenoid molecules, enabled us to distinguish between different triterpenoid materials such as mastic resin, frankincense resin and birch bark pitch, and to graphically plot the resinous substances in three separate clusters, retaining 89% of the total variance. GC/MS analysis of the same materials has permitted us to elucidate in detail the molecular composition and to identify minor components and species that act as markers of the degradation undergone by the materials. The paper also reports the results for the organic residues contained in an Egyptian censer (5th-7th century AD) which was recovered in the excavation of the Necropolis of Antinoe (Egypt), and for the hafting material found on a Palaeolithic tool recovered at the site of Campitello (Arezzo, Tuscany), dating back to the Mid-Pleistocene period. Although DE-MS was found to be a fast analytical tool, it failed to give any information on the presence of less abundant compounds when applied to mixtures of different materials: only mastic resin was found in the residues from the Roman censer, whereas GC/MS analysis identified the presence of a vegetable oil from Brassicaceae seeds and Pinaceae resin. Birch bark pitch as a pure material was identified in the sample from the Palaeolithic flint flake using both procedures. PMID:16676320

  9. General factors of the Korean exposure factors handbook.

    PubMed

    Jang, Jae-Yeon; Kim, So-Yeon; Kim, Sun-Ja; Lee, Kyung-Eun; Cheong, Hae-Kwan; Kim, Eun-Hye; Choi, Kyung-Ho; Kim, Young-Hee

    2014-01-01

    Risk assessment considers the situations and characteristics of the exposure environment and host. Various physiological variables of the human body reflects the characteristics of the population that can directly influence risk exposure. Therefore, identification of exposure factors based on the Korean population is required for appropriate risk assessment. It is expected that a handbook about general exposure factors will be used by professionals in many fields as well as the risk assessors of the health department. The process of developing the exposure factors handbook for the Korean population will be introduced in this article, with a specific focus on the general exposure factors including life expectancy, body weight, surface area, inhalation rates, amount of water intake, and soil ingestion targeting the Korean population. The researchers used national databases including the Life Table and the 2005 Time Use Survey from the National Statistical Office. The anthropometric study of size in Korea used the resources provided by the Korean Agency for Technology and Standards. In addition, direct measurement and questionnaire surveys of representative samples were performed to calculate the inhalation rate, drinking water intake, and soil ingestion. PMID:24570802

  10. Aboveground net primary productivity and rainfall use efficiency of grassland on three soils after two years of exposure to a subambient to superambient CO2 gradient.

    NASA Astrophysics Data System (ADS)

    Fay, P. A.; Polley, H. W.; Jin, V. L.

    2008-12-01

    Atmospheric CO2 concentrations (CA) have increased by about 100 μL L-1 over the last 250 years to ~ 380 μL L-1, the highest values in the last half-million years, and CA is expected to continue to increase to greater than 500 μL L-1 by 2100. CO2 enrichment has been shown to affect many ecosystem processes, but experiments typically examine only two or a few levels of CA, and are typically constrained to one soil type. However, soil hydrologic properties differ across the landscape. Therefore, variation in the impacts of increasing CA on ecosystem function on different soil types must be understood to model and forecast ecosystem function under future CA and climate scenarios. Here we evaluate the aboveground net primary productivity (ANPP) of grassland plots receiving equal rainfall inputs (from irrigation) and exposed to a continuous gradient (250 to 500 μL L-1) of CA in the Lysimeter CO2 Gradient Experiment in central Texas, USA. Sixty intact soil monoliths (1 m2 x 1.5 m deep) taken from three soil types (Austin silty clay, Bastrop sandy loam, Houston clay) and planted to seven native tallgrass prairie grasses and forbs were exposed to the CA gradient beginning in 2006. Aboveground net primary productivity was assessed by end of season (November) harvest of each species in each monolith. Total ANPP of all species was 35 to 50% greater on Bastrop and Houston soils compared to Austin soils in both years (p < 0.0001), suggesting greater rainfall use efficiency on these soils despite lower water holding capacity of the Bastrop soils. On the Austin soil, grasses produced 2.7 fold more biomass than forbs, compared to only 30% more grass biomass on the Houston soil (p = 0.002), suggesting that grass dominance of community and ecosystem processes differed strongly among the soils. Total ANPP was strongly responsive to the CO2 gradient, with mean ANPP increasing from 260 g m- 2 at 250 μL L-1 CA to 455 g m-2 at 500 μL L-1 (p< 0.0001), suggesting greater overall

  11. The Soil Is Alive!

    ERIC Educational Resources Information Center

    Science and Children, 1989

    1989-01-01

    Describes activities which demonstrate the abundance of organisms living underground. Provides outlined directions, lists of materials, and a soil ecosystem transparency for delving into the properties of soil. (RT)

  12. Potential bioavailability of lead, arsenic, and polycyclic aromatic hydrocarbons in compost-amended urban soils.

    PubMed

    Attanayake, Chammi P; Hettiarachchi, Ganga M; Martin, Sabine; Pierzynski, Gary M

    2015-05-01

    Urban soils may contain harmful concentrations of contaminants, such as lead (Pb), arsenic (As), and polycyclic aromatic hydrocarbons (PAHs), that can transfer from soil to humans via soil ingestion and consumption of food crops grown in such soils. The objective of this research was to assess the effectiveness of adding different compost types to reduce both direct (soil-human) and indirect (soil-plant-human) exposure of Pb, As, and PAHs to humans. A field experiment was conducted in 2011 and 2012 at an urban garden site with elevated concentrations of Pb (475 mg kg), As (95 mg kg), and PAHs (23-50 mg kg). Soil amendments were composted biosolids, noncomposted biosolids, mushroom compost, leaf compost, and a nonamended control. Collard greens, tomatoes, and carrots were then grown in the amended and nonamended soils and nonamended soils that received urea in 2011. At the beginning of the second season, N-P-K fertilizer was added to all plots. The potential for direct and indirect exposure was evaluated. Soil Pb bioaccessibility was 1 to 4.3%, and As bioaccessibility was 7.3 to 12.3%. Composted biosolids reduced the bioaccessibility of soil Pb by ∼17% compared with the control but temporarily increased the bioaccessibility of As by ∼ 69% compared with the control when soluble inorganic P concentration in soil was elevated by P fertilizer application in 2012. The bioaccessibility of soil Pb decreased by ∼38% in all treatments when soluble inorganic P concentration in soil was elevated by P fertilizer. Compost amendments reduced the concentrations of low molecular weight PAHs in soil. Regardless of the treatments, the concentrations of Pb, As, and PAHs measured in the vegetables were low or nondetectable, except for Pb in carrots. Consumption of vegetables grown at this site will cause insignificant transfer of Pb, As, and PAHs to humans. PMID:26024273

  13. Subsistence Exposure Scenarios for Tribal Applications

    PubMed Central

    Harper, Barbara; Harding, Anna; Harris, Stuart; Berger, Patricia

    2014-01-01

    The article provides an overview of methods that can be used to develop exposure scenarios for unique tribal natural resource usage patterns. Exposure scenarios are used to evaluate the degree of environmental contact experienced by people with different patterns of lifestyle activities, such as residence, recreation, or work. in 1994, U.S. President Bill Clinton's Executive Order 12898 recognized that disproportionately high exposures could be incurred by people with traditional subsistence lifestyles because of their more intensive contact with natural resources. Since then, we have developed several tribal exposure scenarios that reflect tribal-specific traditional lifeways. These scenarios are not necessarily intended to capture contemporary resource patterns, but to describe how the resources were used before contamination or degradation, and will be used once again in fully traditional ways after cleanup and restoration. The direct exposure factors for inhalation and soil ingestion rates are the same in each tribal scenario, but the diets are unique to each tribe and its local ecology, natural foods, and traditional practices. Scenarios, in part or in whole, also have other applications, such as developing environmental standards, evaluating disproportionate exposures, developing sampling plans, planning for climate change, or evaluating service flows as part of natural resource damage assessments. PMID:25197207

  14. Comparison of the Bioavailability of Waste Laden Soils Using ''In Vivo'' ''In Vitro'' Analytical Methodology and Bioaccessibility of Radionuclides for Refinement of Exposure/Dose Estimates

    SciTech Connect

    P. J. Lioy; M. Gallo; P. Georgopoulos; R. Tate; B. Buckley

    1999-09-15

    The bioavailability of soil contaminants can be measured using in vitro or in vivo techniques. Since there was no standard method for intercomparison among laboratories, we compared two techniques for bioavailability estimation: in vitro dissolution and in vivo rat feeding model for a NIST-traceable soil material. Bioaccessibility was measured using a sequential soil extraction in synthetic analogues of human saliva, gastric and intestinal fluids. Bioavailability was measured in Sprague Dawley rats by determining metal levels in the major organs and urine, feces, and blood. Bioaccessibility was found to be a good indicator of relative metal bioavailability. Results are presented from bioaccessible experiments with Cesium in contaminated DOE soils, and total alpha and beta bioaccessibility. The results indicate that the modified methodology for bioaccessibility can be used for specific radionuclide analysis.

  15. Occurrence of Hexabromocyclododecane in soil and road dust from mixed-land-use areas of Shanghai, China, and its implications for human exposure.

    PubMed

    Wu, Ming-Hong; Han, Tao; Xu, Gang; Zang, Chao; Li, Yi-Jie; Sun, Rui; Xu, Ben-Tuo; Sun, Yan; Chen, Fen-Fen; Tang, Liang

    2016-07-15

    Herein, the occurrence of three Hexabromocyclododecane (HBCDD) diastereoisomers in soil and road dust from the mixed-land-use areas in Shanghai was investigated. The total concentrations of HBCDDs (∑HBCDDs) in soil ranged from 0.30 to 249ngg(-1)dw, with a median level of 5.14ngg(-1)dw. For the road dust samples, the ΣHBCDD concentrations varied from 4.11 to 508ngg(-1)dw, with a median level of 23.4ngg(-1)dw. The levels of HBCDDs varied in different mixed-land-use areas. In soil, the levels of HBCDDs increased in the following sequence: residential area & agricultural area (R&A)soil. For soil, the portion of α-HBCDD increased in the following sequence: R&Isoil and road dust from R&C and R&I were found, which suggested that they may share similar sources in these regions. On the basis of the HBCDD concentrations of road dust and soil, the contributions of ingestion, dermal contact absorption and inhalation intake to total estimated daily intakes (EDIs) were estimated. The highest total EDIs of ∑HBCDDs (sum of ingestion, dermal contact absorption and inhalation intake) were 0.154, 7.5×10(-2)ngkg(-1)d(-1) for infants from road dust and soil in R&I, respectively. PMID:27065447

  16. Exposure of school children to polycyclic aromatic hydrocarbons, heavy metals and radionuclides in the urban soil of Kragujevac city, Central Serbia.

    PubMed

    Stajic, J M; Milenkovic, B; Pucarevic, M; Stojic, N; Vasiljevic, I; Nikezic, D

    2016-03-01

    The concentrations of radionuclides, polycyclic aromatic hydrocarbons (PAHs) and heavy metals were measured in soil samples collected from school backyards and playgrounds in Kragujevac, one of the largest cities of Central Serbia. The activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined using the HPGe semiconductor detector. The average values were 34.6, 44.7, 428.9 and 45.1 Bq kg(-1), respectively. The correlation between the activity concentrations of (226)Ra in the soil samples and the results of the previous measurement of (222)Rn concentrations in the indoor air was examined. The absorbed dose rates, the annual effective doses and excess lifetime cancer risk were also estimated. The activity concentrations of (226)Ra and (232)Th have shown normal distribution. The collected soil samples were analysed for PAHs by HPLC. All analysed soil samples contained PAHs, and their total amounts (for 15 measured compounds) were found to be between 0.038 and 3.136 mg kg(-1) of absolutely dry soil (a.d.s). In addition the concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in the fourteen soil samples collected from the playgrounds of kindergartens. PMID:26706933

  17. Comparison of the bioavailability of elemental waste laden soils using in vivo and in vitro analytical methodology and refinement of exposure/dose model. 1997 annual progress report

    SciTech Connect

    Gailo, M.; Georgopoulos, P.; Lioy, P.J.; Roy, A.

    1997-01-01

    'The bioavailability study has made significant progress in developing in vitro methodology, and the authors have completed the time course in vivo studies. The in vitro studies have been conducted to establish the major digestive variables of concern and the values to be used in application of both the saliva/gastric juice and intestinal fluid components of a synthetic digestive extraction. In vitro and in vivo experiments have been conducted on the 575 urn particle fraction of a soil sample collected in a Jersey City State Park. Five Jersey City soil samples were first characterized for physical and chemical characteristics. Based upon the composition of the five soils, one was selected for use in the first series of experiments. The second set of in vivo studies are to be conducted on a standard NIST Montana soil. It has already been examined for bioaccessibility and availability with the in vitro methodology. A sample has been collected in Bayonne to obtain an urban background soil. Surficial soil samples have been acquired from the Savannah River Site of the DOE. These are not radioactive but are contaminated with heavy metals, e.g. arsenic, and are being analyzed by both the in vivo and in vitro methodology. During this past summer a second set of soil samples were collected at Savannah River Site. These contain levels of both heavy metals and radionuclides. Recently, a special extraction laboratory has been constructed at EOHSI, with resources made available from the organization. It will handle the extraction and measurement of the radio activity of the soil, and extracts obtained by the in vivo techniques. It is anticipated that the SRS samples collected this summer will be available for analysis in both the in vivo and in vitro systems this fall. The initial characterization will be for soil, physical and chemical content, and microbial characteristics. The samples will be analyzed for the 5 75 urn particle size fraction, and the total mass 5 250 urn in

  18. Lead in Urban Soils: A Real or Perceived Concern for Urban Agriculture?

    PubMed

    Brown, Sally L; Chaney, Rufus L; Hettiarachchi, Ganga M

    2016-01-01

    Urban agriculture is growing in cities across the United States. It has the potential to provide multiple benefits, including increased food security. Concerns about soil contamination in urban areas can be an impediment to urban agriculture. Lead is the most common contaminant in urban areas. In this paper, direct (soil ingestion via outdoor and indoor exposure) and indirect (consumption of food grown in Pb-contaminated soils) exposure pathways are reviewed. It is highly unlikely that urban agriculture will increase incidences of elevated blood Pb for children in urban areas. This is due to the high likelihood that agriculture will improve soils in urban areas, resulting in reduced bioavailability of soil Pb and reduced fugitive dust. Plant uptake of Pb is also typically very low. The exceptions are low-growing leafy crops where soil-splash particle contamination is more likely and expanded hypocotyl root vegetables (e.g., carrot). However, even with higher bioaccumulation factors, it is not clear that the Pb in root vegetables or any other crops will be absorbed after eating. Studies have shown limited absorption of Pb when ingested with food. Best management practices to assure minimal potential for exposure are also common practices in urban gardens. These include the use of residuals-based composts and soil amendments and attention to keeping soil out of homes. This review suggests that benefits associated with urban agriculture far outweigh any risks posed by elevated soil Pb. PMID:26828157

  19. Environmental fate and exposure; neonicotinoids and fipronil.

    PubMed

    Bonmatin, J-M; Giorio, C; Girolami, V; Goulson, D; Kreutzweiser, D P; Krupke, C; Liess, M; Long, E; Marzaro, M; Mitchell, E A D; Noome, D A; Simon-Delso, N; Tapparo, A

    2015-01-01

    Systemic insecticides are applied to plants using a wide variety of methods, ranging from foliar sprays to seed treatments and soil drenches. Neonicotinoids and fipronil are among the most widely used pesticides in the world. Their popularity is largely due to their high toxicity to invertebrates, the ease and flexibility with which they can be applied, their long persistence, and their systemic nature, which ensures that they spread to all parts of the target crop. However, these properties also increase the probability of environmental contamination and exposure of nontarget organisms. Environmental contamination occurs via a number of routes including dust generated during drilling of dressed seeds, contamination and accumulation in arable soils and soil water, runoff into waterways, and uptake of pesticides by nontarget plants via their roots or dust deposition on leaves. Persistence in soils, waterways, and nontarget plants is variable but can be prolonged; for example, the half-lives of neonicotinoids in soils can exceed 1,000 days, so they can accumulate when used repeatedly. Similarly, they can persist in woody plants for periods exceeding 1 year. Breakdown results in toxic metabolites, though concentrations of these in the environment are rarely measured. Overall, there is strong evidence that soils, waterways, and plants in agricultural environments and neighboring areas are contaminated with variable levels of neonicotinoids or fipronil mixtures and their metabolites (soil, parts per billion (ppb)-parts per million (ppm) range; water, parts per trillion (ppt)-ppb range; and plants, ppb-ppm range). This provides multiple routes for chronic (and acute in some cases) exposure of nontarget animals. For example, pollinators are exposed through direct contact with dust during drilling; consumption of pollen, nectar, or guttation drops from seed-treated crops, water, and consumption of contaminated pollen and nectar from wild flowers and trees growing near

  20. Acidification of forest soil in Russia: From 1893 to present

    USGS Publications Warehouse

    Lapenis, A.G.; Lawrence, G.B.; Andreev, A.A.; Bobrov, A.A.; Torn, M.S.; Harden, J.W.

    2004-01-01

    It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30-40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils developed on calcareous silt loam. In a chemical analysis comparing archived soils with modern soils collected from the same locations ???100 years later, we found varying degrees of forest-soil acidification in the taiga and forest steppe regions. Land-use history, increases in precipitation, and acidic deposition were contributing factors in acidification. The acidification of forest soil was documented through decreases in soil pH and changes in concentrations of exchangeable calcium and aluminum, which corresponded with changes in communities of soil microfauna. Although acidification was found at all three analyzed locations, the trends in soil chemistry were most pronounced where the highest loading of acidic deposition had taken place. Copyright 2004 by the American Geophysical Union.

  1. Acidification of forest soil in Russia: From 1893 to present

    SciTech Connect

    Lapenis, A.G.; Lawrence, G.B.; Andreev, A.A.; Bobrov, A.A.; Torn, M.S.; Harden, J.W.

    2003-01-02

    It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30-40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils developed on calcareous silt loam. In a chemical analysis comparing archived soils with modern soils collected from the same locations similar to 100 years later, we found varying degrees of forest-soil acidification in the taiga and forest steppe regions. Land-use history, increases in precipitation, and acidic deposition were contributing factors in acidification. The acidification of forest soil was documented through decreases in soil pH and changes in concentrations of exchangeable calcium and aluminum, which corresponded with changes in communities of soil microfauna. Although acidification was found at all three analyzed locations, the trends in soil chemistry were most pronounced where the highest loading of acidic deposition had taken place.

  2. [Strategy in directed preventive studies. I. Evaluation of health effects of exposure to carcinogenic factors. Problem of development- al anomalies and neoplasms in children. Reproduction disorders].

    PubMed

    Indulski, J A; Kowalski, Z

    1990-01-01

    In highly developed countries the prophylactic medical examinations to evaluate health effects of exposure and general health condition of the workers started early in the past. Nowadays, there is an increasing trend of developing new methods for early detection of occupational and work--related diseases. Thus the individuals oversensitive to the agents of the working environment could be prevented from exposure. However, the gap between the capacities that the new methods offer theoretically and their actual application in the prophylactic examinations still remains quite large. Part I of the present study has been devoted to three essential problems of public concern which have been specified in the paper's subtitles. PMID:2131393

  3. Soil adherence to human skin

    SciTech Connect

    Driver, J.H.; Konz, J.J.; Whitmyre, G.K. )

    1989-12-01

    Dermal exposure to soils contaminated with toxic chemicals represents a potential public health hazard. These soils, contaminated with chemicals such as PCBs and dioxins, may be found at various locations throughout the US. Furthermore, dermal contact with pesticide-containing particles and contaminated soil particles is of importance for exposures to agricultural workers who reenter fields after pesticide application. With respect to dermal exposure to pesticide-contaminated particulate matter, several occurrences of human toxicity to ethyl parathion in citrus groves have been reported. These exposures resulted from dermal contact with high concentrations of the toxic transformation product paraoxon in soil dust contaminated as a result of application of pesticide to the overhead foliage of trees. To assess dermal exposure to chemically-contaminated soil at sites of concern, dermal adherence of soil must be determined prior to the assessment of dermal absorption. The purpose of the experiment reported herein was to determine the amount of soil (mg/cm{sup 2}) that adheres to adult hands under various soil conditions. These conditions include the type of soil, the organic content of the soil, and the particle size of the soil.

  4. Effects of direct land application of calcitic lime and lime- and cement kiln dust-sanitized biosolids on the chemical and spectroscopic characteristics of soil lipids

    SciTech Connect

    Dinel, H.; Schnitzer, M.; Pare, T.; Topp, E. ); Lemee, L.; Ambles, A. . Lab. de Chimie); Pelzer, N. )

    1999-05-01

    To determine the extent to which applications of calcitic lime and sanitized biosolids affect the quality of soil organic matter (SOM), lipids extracted from an unamended soil (CON) and from soils amended with calcitic lime (CAL), and lime (LSB)- and cement kiln dust (CDB)-sanitized biosolids were characterized by chemical analysis and Pyrolysis-Gas chromatography (Py-GC). From diethyl ether (DEE) and CHCl[sub 3] soluble lipids, and from weight ratios of the extracts, the organic matter in the soil amended with CDB-treated biosolids seemed to be more biodegraded and biochemically inert than the organic matter in soils that received LSB-treated biosolids and calcitic lime and that in the control soil.

  5. Role of water repellency in aggregate stability of cultivated soils under simulated raindrop impact

    NASA Astrophysics Data System (ADS)

    Kořenková, Lucia; Matúš, Peter

    2015-07-01

    Soil aggregate stability (AS) is an important indicator of soil physical quality. For the purpose of this research it was hypothesized that particular properties such as water repellency (WR) influence soil aggregation and AS. Directly after sampling, WR was detected for three soils, after a week of air-drying two of these soils still showed some resistance to penetration by a water drop placed on the surface (WDPT test). The study examines AS of air-dried texturally different aggregates of size 0.25-0.5 mm taken from surface layers (5-15 cm depth) of six agriculturally used soils. The procedure involves exposure of soil aggregates to direct impact of water drops. Results showed that soil AS increases in order: cutanic Luvisol (siltic) < haplic Chernozem < calcic mollic Fluvisol < mollic grumic Vertisol (pellic) < mollic Fluvisol (calcaric) < gleyic Fluvisol (eutric). Gradual increase in AS can be explained by the increase in soil organic matter content and its hydrophobic properties. Although WR has been most commonly observed in soils under forests and grass cover, the results confirmed that cultivated soils may also create water-stable aggregates, especially in the case when their organic matter induces WR under particular moisture conditions.

  6. A STABLE ISOTOPE ANALYSIS OF SOIL CARBON DENSITY FRACTIONS FOLLOWING 4 YEARS OF CONTINUOUS CLIMATE CHANGE EXPOSURE IN A DOUGLAS FIR MESOCOSM STUDY

    EPA Science Inventory

    We conducted a 4-year full-factorial study of the effects of elevated atmospheric CO2 and temperature on Douglas fir seedlings growing in reconstructed native forest soils in mesocosms. The elevated CO2 treatment was ambient CO2 plus 200 ppm CO2. The elevated temperature treatm...

  7. Estimating Exposure of Terrestrial Wildlife to Contaminants

    SciTech Connect

    Sample, B.E.

    1994-01-01

    This report presents a general model for exposure of terrestrial wildlife to contaminants (Sect. 2), methods for estimating parameters of the model (Sect. 3), species specific parameters for endpoint species on the Oak Ridge Reservation (ORR) (Sect. 4), and a sample application (Sect. 5). Exposure can be defined as the coincidence in both space and time of a receptor and a stressor, such that the receptor and stressor come into contact and interact (Risk Assessment Forum 1992). In the context of ecological risk assessment, receptors include all endpoint species or communities identified for a site [see Suter (1989) and Suter et al. (1994) for discussions of ecological endpoints for waste sites]. In the context of waste site assessments, stressors are chemical contaminations, and the contact and interaction are uptake of the contaminant by the receptor. Without sufficient exposure of the receptor to the contaminants, there is no ecological risk. Unlike some other endpoint assemblages, terrestrial wildlife are significantly exposed to contaminants in multiple media. They may drink or swim in contaminated water, ingest contaminated food and soil, and breath contaminated air. In addition, because most wildlife are mobile, moving among and within habitats, exposure is not restricted to a single location. They may integrate contamination from several spatially discrete sources. Therefore, exposure models for terrestrial wildlife must include multiple media. This document provides models and parameters for estimating exposure of birds and mammals. Reptiles and amphibians are not considered because few data exist with which to assess exposure to these organisms. In addition, because toxicological data are scarce for both classes, evaluation of the significance of exposure estimates is problematic. However, the general exposure estimation procedure developed herein for birds and mammals is applicable to reptiles and amphibians. Exposure models must be appropriate to the

  8. Poinsettia plant exposure

    MedlinePlus

    Christmas flower poisoning; Lobster plant poisoning; Painted leaf poisoning ... Leaves, stem, sap of the poinsettia plant ... Poinsettia plant exposure can affect many parts of the body. EYES (IF DIRECT CONTACT OCCURS) Burning Redness STOMACH AND ...

  9. The impact of exposure to peer suicidal self-directed violence on youth suicidal behavior: a critical review of the literature.

    PubMed

    Crepeau-Hobson, M Franci; Leech, Nancy L

    2014-02-01

    There is considerable evidence that being exposed to the suicide or suicidal behavior of another can increase the risk for suicide. Significant relationships between media coverage and youth suicide have been documented in the professional literature. Exposure to familial suicidal behavior has also been established as a risk factor for youth suicidal behavior; However, peer suicide exposure is not as clear cut as research results in this area have been mixed. In the current paper the empirical literature focused on the associations between exposure to peer suicides and suicide attempts and youth suicidal behavior is critically reviewed. Effect sizes were computed for each of the 23 studies included in the review to allow for cross-study comparisons. The results demonstrate that having a friend or acquaintance attempt suicide is significantly related to risk for suicidal thoughts and behavior. However, the support for the relationship between the suicide of a peer and youth suicidal behavior was less consistent. Implications for clinical practice and suicide postvention as well as areas of future research are discussed. PMID:24033603

  10. Exposure to naturally circulating androgens during foetal life incurs direct reproductive costs in female spotted hyenas, but is prerequisite for male mating.

    PubMed Central

    Drea, C M; Place, N J; Weldele, M L; Coscia, E M; Licht, P; Glickman, S E

    2002-01-01

    Among all extant mammals, only the female spotted hyena (Crocuta crocuta) mates and gives birth through the tip of a peniform clitoris. Clitoral morphology is modulated by foetal exposure to endogenous, maternal androgens. First births through this organ are prolonged and remarkably difficult, often causing death in neonates. Additionally, mating poses a mechanical challenge for males, as they must reach an anterior position on the female's abdomen and then achieve entry at the site of the retracted clitoris. Here, we report that interfering with the actions of androgens prenatally permanently modifies hyena urogenital anatomy, facilitating subsequent parturition in nulliparous females who, thereby, produce live cubs. By contrast, comparable, permanent anatomical changes in males probably preclude reproduction, as exposure to prenatal anti-androgens produces a penis that is too short and has the wrong shape necessary for insertion during copulation. These data demonstrate that the reproductive costs of clitoral delivery result from exposure of the female foetus to naturally circulating androgens. Moreover, the same androgens that render an extremely unusual and laborious process even more reproductively costly in the female are apparently essential to the male's physical ability to reproduce with a normally masculinized female. PMID:12396496

  11. Is received dose from ingested soil independent of soil PAH concentrations?-Animal model results.

    PubMed

    Peters, Rachel E; James, Kyle; Cave, Mark; Wickstrom, Mark; Siciliano, Steven D

    2016-09-01

    Polycyclic aromatic hydrocarbon (PAH) bioavailability from ingested soils will vary between soils; however, the nature of this variation is not well characterized. A juvenile swine model was used to link external exposure to internal benzo[a]pyrene (BaP) and anthracene exposure following oral PAH ingestion of 27 different impacted site soils, soots, or spiked artificial soils. Internal exposure of BaP and anthracene, represented by area under the plasma-time curve, did not relate to soil concentration in impacted site soils, but did relate in spiked artificial soil. Point of departure modeling identified soil PAH concentrations greater than 1900 mg kg(-1) as the point where area under the curve becomes proportional to external dose. A BaP internal exposure below 1900 mg kg(-1) had an upper 95% confidence interval estimate of 33% of external exposure. Weak relationships between soil:simulated gastrointestinal fluid PAH partitioning and area under the curve values suggest that differences in internal PAH exposure between soils may not be dominated by differences in PAH partitioning. The data seem to best support exposure assessment assuming constant internal PAH exposure below soil concentrations of 1900 mg kg(-1) . However, because constant internal exposure would challenge several existing paradigms, a bioavailability estimate of 33% of the external exposure is suggested as a likely workable solution. Environ Toxicol Chem 2016;35:2261-2269. © 2016 SETAC. PMID:26815007

  12. H2-saturation of high affinity H2-oxidizing bacteria alters the ecological niche of soil microorganisms unevenly among taxonomic groups

    PubMed Central

    Piché-Choquette, Sarah; Tremblay, Julien; Tringe, Susannah G.

    2016-01-01

    Soil microbial communities are continuously exposed to H2 diffusing into the soil from the atmosphere. N2-fixing nodules represent a peculiar microniche in soil where H2 can reach concentrations up to 20,000 fold higher than in the global atmosphere (0.530 ppmv). In this study, we investigated the impact of H2 exposure on soil bacterial community structure using dynamic microcosm chambers simulating soil H2 exposure from the atmosphere and N2-fixing nodules. Biphasic kinetic parameters governing H2 oxidation activity in soil changed drastically upon elevated H2 exposure, corresponding to a slight but significant decay of high affinity H2-oxidizing bacteria population, accompanied by an enrichment or activation of microorganisms displaying low-affinity for H2. In contrast to previous studies that unveiled limited response by a few species, the relative abundance of 958 bacterial ribotypes distributed among various taxonomic groups, rather than a few distinct taxa, was influenced by H2 exposure. Furthermore, correlation networks showed important alterations of ribotype covariation in response to H2 exposure, suggesting that H2 affects microbe-microbe interactions in soil. Taken together, our results demonstrate that H2-rich environments exert a direct influence on soil H2-oxidizing bacteria in addition to indirect effects on other members of the bacterial communities. PMID:26989620

  13. Estimate of the dose-increment due to outdoor exposure to gamma rays from uranium progeny deposited on the soil around a coal-fired power plant in Ajka Town, Hungary.

    PubMed

    Papp, Z; Dezsö, Z

    2003-06-01

    Brown coal unusually rich in uranium is burnt in a coal-fired power plant that lies inside the confines of a small industrial town named Ajka, Hungary, and has been operational since 1943. The 238U (226Ra) activity discharged to the atmosphere per unit electrical energy produced was about 330-400 GBq (GW y)(-1), which is 66-80 times more than that was estimated by UNSCEAR (1988) as a characteristic value for old type coal-fired power plants [5 GBq (GW y)(-1)]. The objective of this study was the experimentally established assessment of the artificial increment in the dose from external exposure to gamma rays of terrestrial radionuclides outdoors. Soil samples were collected in and near Ajka from 81 locations. The samples were investigated by Ge(Li) gamma spectrometry. Considerably elevated concentrations of uranium and its progeny have been measured in most of the samples that were collected near to the plant. Concentrations of 238U and 226Ra in the top (0-5 cm depth) layer of undisturbed soil at public areas inside town were 4.7 times higher, on average, than those in the uncontaminated deeper layers. Dose rate in air (air kerma) from external exposure to terrestrial gamma rays outdoors at a height of 1 m and effective doses were estimated from the measured activity concentrations using some relevant literature data. The estimated artificial increment in the dose rate in air was, on average, 32.8, 10.3, and 102.1 nGy h(-1) at public areas, vegetable gardens, and backyards, respectively. The mean artificial increment in the annual per caput effective dose from external exposure to terrestrial radionuclides outdoors is 21.8 microSv y(-1). The collective dose commitment per unit energy generated from outdoor exposure to the deposited uranium progeny is about 8.0-9.1 person Sv (GW y)(-1), which is 67-76 times more than that evaluated by UNSCEAR (1988) for a typical "old" coal-fired power plant [0.12 person Sv (GW y)(-1)]. Ajka is a suitable place for studying the

  14. Biomarkers of xenobiotic exposures

    SciTech Connect

    Brewster, M.A.

    1988-07-01

    Direct measurement of xenobiotic (foreign) chemicals is not always feasible as an exposure assessment,--owing to rapid metabolism, sequestration into fatty tissues, or lack of suitable assay methods. Furthermore, suspect exposures often involve complex mixtures of organics. In these circumstances, indirect biomarkers of exposure can be most helpful. This paper reviews four urinary parameters that hold promise as biomarkers of exposure in occupational and environmental settings: glucaric acid (end-product of the glucuronidation pathway), thioethers (end-product of glutathione reaction with electrophilic or alkylating agents), porphyrin pattern (altered with disruption in heme biosynthesis), and the Ames mutagenicity test. 112 references.

  15. Development of the county database: Estimates of exposure rates and times of arrival of fallout in the ORERP Phase-2 area. Comparison with cumulative deposition-density estimates based on analyses of retrospective and historical soil samples

    SciTech Connect

    Beck, H.L.; Anspaugh, L.R.

    1991-12-01

    Estimates of exposure rates and fallout-arrival times have been made for each of 142 counties or county segments for 55 nuclear events producing significant deposition downwind from the Nevada Test Site. All sources of available data were examined to provide the best possible estimates for each event. The cumulative fallout deposited per unit area in each county based on these estimates is compared with estimates of cumulative deposition density based on analyses of contemporary and historical soil samples. The good agreement between the two sets of cumulative deposition estimates gives credence to the individual event estimates and suggests that no major sources of fission-product deposition were overlooked. This county database is being used as primary input data in a number of on-going dose-reconstruction studies.

  16. CORRELATING METAL SPECIATION IN SOILS TO RISK

    EPA Science Inventory

    Understanding bioavailability of metals from exposure to contaminated soils is a challenging aspect of environmental research. This presentation will examine three areas of research with respect to metal speciation in soils as it relates to bioavailability: 1) Pb immobilization a...

  17. Separating Family-Level and Direct Exposure Effects of Smoking During Pregnancy on Offspring Externalizing Symptoms: Bridging the Behavior Genetic and Behavior Teratologic Divide.

    PubMed

    Estabrook, Ryne; Massey, Suena H; Clark, Caron A C; Burns, James L; Mustanski, Brian S; Cook, Edwin H; O'Brien, T Caitlin; Makowski, Beth; Espy, Kimberly A; Wakschlag, Lauren S

    2016-05-01

    Maternal smoking during pregnancy (MSDP) has been robustly associated with externalizing problems and their developmental precursors in offspring in studies using behavioral teratologic designs (Wakschlag et al., Am J Public Health 92(6):966-974, 2002; Espy et al., Dev Psychol 47(1):153-169, 2011). In contrast, the use of behavior genetic approaches has shown that the effects commonly attributed to MSDP can be explained by family-level variables (D'Onofrio et al., Dev Psychopathol 20(01):139-164, 2008). Reconciling these conflicting findings requires integration of these study designs. We utilize longitudinal data on a preschool proband and his/her sibling from the Midwest Infant Development Study-Preschool (MIDS-P) to test for teratologic and family level effects of MSDP. We find considerable variation in prenatal smoking patterns both within and across pregnancies within families, indicating that binary smoking measures are not sufficiently capturing exposure. Structural equation models indicate that both conduct disorder and oppositional defiant disorder symptoms showed unique effects of MSDP over and above family level effects. Blending high quality exposure measurement with a within-family design suggests that it is premature to foreclose the possibility of a teratologic effect of MSDP on externalizing problems. Implications and recommendations for future studies are discussed. PMID:26581695

  18. Transfer of metals and metalloids from soil to shoots in wild rosemary (Rosmarinus officinalis L.) growing on a former lead smelter site: human exposure risk.

    PubMed

    Affholder, Marie-Cécile; Prudent, Pascale; Masotti, Véronique; Coulomb, Bruno; Rabier, Jacques; Nguyen-The, Bénédicte; Laffont-Schwob, Isabelle

    2013-06-01

    This study aimed at estimating exposition risks to wild rosemary used as herbs in the contaminated area of the former smelting factory of L'Escalette (South of Marseille, France). Metals and metalloids i.e. Pb, As, Sb, Zn, and Cu concentrations were analyzed in soils and in rosemary aerial parts (stems and leaves) on two sites: one heavily contaminated and the other far away from the pollution source, considered as reference. The metal and metalloid transfer into water during the brewing process of herbal tea was also determined. A mixed contamination by the above-cited contaminants was demonstrated in soils of the factory site, with average concentrations of 9253, 1127, 309, 2698 and 32 mg/kg for Pb, As, Sb, Zn and Cu, respectively. However, metals and metalloids' transfer in rosemary aerial parts was limited, as bioaccumulation factors were under 1. Thus, Pb, As and Cu concentrations in leaves were below international regulation limits concerning ingestion of medicinal herbs (no regulation values available for Sb and Zn). This study highlighted that, if contaminated rosemary leaves were ingested, health risks may be limited since acceptable daily intake (ADI) for Pb, As, Sb and Cu (no ADI value available for Zn) will only be reached if very high quantities are consumed. Furthermore, we aimed to establish if this mixed contamination could alter rosemary's essential oil quality, and thereby the compositions of essential oils obtained from individuals on the heavily contaminated soil were compared to those obtained from the reference population. An increased biosynthesis of antioxidant compounds was favored in essential oils from rosemary individuals growing in contaminated site. Although the health risk of a long-term exposition of low level of the mixed contamination by rosemary ingestion is not easy to elucidate, the use of rosemary essential oils from contaminated site appears as safe. PMID:23542674

  19. 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. PMID:25697405

  20. Soil fauna, soil properties and geo-ecosystem functioning

    NASA Astrophysics Data System (ADS)

    Cammeraat, L. H.

    2012-04-01

    The impact of soil fauna on soil processes is of utmost importance, as the activity of soil fauna directly affects soil quality. This is expressed by the direct effects of soil fauna on soil physical and soil chemical properties that not only have great importance to food production and ecosystems services, but also on weathering and hydrological and geomorphological processes. Soil animals can be perceived as ecosystem engineers that directly affect the flow of water, sediments and nutrients through terrestrial ecosystems. The biodiversity of animals living in the soil is huge and shows a huge range in size, functions and effects. Most work has been focused on only a few species such as earthworms and termites, but in general the knowledge on the effect of soil biota on soil ecosystem functioning is limited as it is for their impact on processes in the soil and on the soil surface. In this presentation we would like to review some of the impacts of soil fauna on soil properties that have implications for geo-ecosystem functioning and soil formation processes.

  1. Long-term antibiotic exposure in soil is associated with changes in microbial community structure and prevalence of class 1 integrons.

    PubMed

    Cleary, David W; Bishop, Alistair H; Zhang, Lihong; Topp, Edward; Wellington, Elizabeth M H; Gaze, William H

    2016-10-01

    Antimicrobial resistance is one of the most significant challenges facing the global medical community and can be attributed to the use and misuse of antibiotics. This includes use as growth promoters or for prophylaxis and treatment of bacterial infection in intensively farmed livestock from where antibiotics can enter the environment as residues in manure. We characterised the impact of the long-term application of a mixture of veterinary antibiotics alone (tylosin, sulfamethazine and chlortetracycline) on class 1 integron prevalence and soil microbiota composition. Class 1 integron prevalence increased significantly (P < 0.005) from 0.006% in control samples to 0.064% in the treated plots. Soil microbiota was analysed using 16S rRNA gene sequencing and revealed significant alterations in composition. Of the 19 significantly different (P < 0.05) OTUs identified, 16 were of the Class Proteobacteria and these decreased in abundance relative to the control plots. Only one OTU, of the Class Cyanobacteria, was shown to increase in abundance significantly; a curiosity given the established sensitivity of this class to antibiotics. We hypothesise that the overrepresentation of Proteobacteria as OTUs that decreased significantly in relative abundance, coupled with the observations of an increase in integron prevalence, may represent a strong selective pressure on these taxa. PMID:27495240

  2. Ecotoxicological effects of an aged TiO2 nanocomposite measured as apoptosis in the anecic earthworm Lumbricus terrestris after exposure through water, food and soil.

    PubMed

    Lapied, Emmanuel; Nahmani, Johanne Y; Moudilou, Elara; Chaurand, Perrine; Labille, Jérôme; Rose, Jérôme; Exbrayat, Jean-Marie; Oughton, Deborah H; Joner, Erik J

    2011-08-01

    Titanium dioxide nanoparticles seem to have a low toxicity to terrestrial organisms, though few studies are published in this area. TiO(2) used in sunscreens are nanocomposites where TiO(2) has been coated with magnesium, silica or alumina, as well as amphiphilic organics like polydimethyl siloxane (PDMS), and these coatings are modified by ageing. We assessed the ecotoxicity and propensity for bioaccumulation of an aged TiO(2) nanocomposite used in sunscreen cosmetics, and its potential effect on the frequency of apoptosis in different earthworm tissues. The earthworm Lumbricus terrestris was exposed to the TiO(2) nanocomposite for 7 days in water or 2-8 weeks in soil with the nanocomposite mixed either into food or soil at concentrations ranging from 0 to 100 mg kg(-1). Apoptosis was then measured by immunohistochemistry and Ti localized by XRF microscopy. Results showed no mortality, but an enhanced apoptotic frequency which was higher in the cuticule, intestinal epithelium and chloragogenous tissue than in the longitudinal and circular musculature. TiO(2) nanoparticles did not seem to cross the intestinal epithelium/chloragogenous matrix barrier to enter the coelomic liquid, or the cuticule barrier to reach the muscular layers. No bioaccumulation of TiO(2) nanocomposites could thus be observed. PMID:21324526

  3. Trust in online prescription drug information among internet users: the impact on information search behavior after exposure to direct-to-consumer advertising.

    PubMed

    Menon, Ajit M; Deshpande, Aparna D; Perri, Matthew; Zinkhan, George M

    2002-01-01

    The proliferation of both manufacturer-controlled and independent medication-related websites has aroused concern among consumers and policy-makers concerning the trustworthiness of Web-based drug information. The authors examine consumers' trust in on-line prescription drug information and its influence on information search behavior. The study design involves a retrospective analysis of data from a 1998 national survey. The findings reveal that trust in drug information from traditional media sources such as television and newspapers transfers to the domain of the Internet. Furthermore, a greater trust in on-line prescription drug information stimulates utilization of the Internet for information search after exposure to prescription drug advertising. PMID:12749596

  4. Direct exposure to nitrogen dioxide fails to induce the expression of some inflammatory cytokines in an IC-21 murine macrophage cell model.

    PubMed

    Tu, B; Wallin, A; Moldéus, P; Cotgreave, I A

    1995-12-15

    Biologically-active molecules secreted from alveolar macrophages, such as cytokines, have been proposed to be involved in the induction of pulmonary toxicity and inflammation in response to the inhalation of oxidant gas pollutants such as NO2 and O3. Despite this, mechanistic studies are hampered by the difficulty in obtaining control macrophages from human subjects, and the intrinsic variability of such primary cells. It is, thus, of importance to develop alternative models for such studies. Here, we have characterised expression kinetics of the mRNAs for tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), macrophage inflammatory protein-1 alpha (MIP-1 alpha) and macrophage inflammatory protein-1 beta (MIP-1 beta) in confluent cultures of the murine IC-21 macrophage line in response to LPS. The secretion of TNF-alpha protein into the medium, assayed by L-929 cell bioassay, closely followed the expression of its mRNA in response to the LPS stimulus. In contrast to LPS, the exposure of IC-21 cells to either air or various concentrations of NO2 in air between 2 and 20 ppm, in an inverted plate exposure model, failed to induce the expression of any of the cytokine mRNAs probed. We conclude that the IC-21 cell line may represent a suitable model for studying the role of stimulated cytokine gene expression in inflammation and that the early events in the pulmonary inflammatory response to the inhalation of NO2 do not involve stimulated release of TNF-alpha, IL-1 beta or MIP-1 alpha/MIP-1 beta from macrophages. PMID:8560494

  5. The evaluation of stack metal emissions from hazardous waste incinerators: Assessing human exposure through noninhalation pathways

    SciTech Connect

    Sedman, R.M.; Polisini, J.M.; Esparza, J.R.

    1994-06-01

    Potential public health effects associated with exposure to metal emissions from hazardous waste incinerators through noninhalation pathways were evaluated. Instead of relying on modeling the movement of toxicants through various environmental media, an approach based on estimating changes from baseline levels of exposure was employed. Changes in soil and water As, Cd, Hg, Pb, Cr, and Be concentrations that result from incinerator emissions were first determined. Estimates of changes in human exposure due to direct contact with shallow soil or the ingestion of surface water were then ascertained. Projected changes in dietary intakes of metals due to incinerator emissions were estimated based on changes from baseline dietary intakes that are monitored in U.S. Food and Drug Administration total diet studies. Changes from baseline intake were deemed to be proportional to the projected changes in soil or surface water metal concentrations. Human exposure to metals emitted from nine hazardous waste incinerators were then evaluated. Metal emissions from certain facilities resulted in tangible human exposure through noninhalation pathways. However, the analysis indicated that the deposition of metals from ambient air would result in substantially greater human exposure through noninhalation pathways than the emissions from most of the facilities. 51 refs., 1 fig., 6 tabs.

  6. The evaluation of stack metal emissions from hazardous waste incinerators: assessing human exposure through noninhalation pathways.

    PubMed Central

    Sedman, R M; Polisini, J M; Esparza, J R

    1994-01-01

    Potential public health effects associated with exposure to metal emissions from hazardous waste incinerators through noninhalation pathways were evaluated. Instead of relying on modeling the movement of toxicants through various environmental media, an approach based on estimating changes from baseline levels of exposure was employed. Changes in soil and water As, Cd, Hg, Pb, Cr, and Be concentrations that result from incinerator emissions were first determined. Estimates of changes in human exposure due to direct contact with shallow soil or the ingestion of surface water were then ascertained. Projected changes in dietary intakes of metals due to incinerator emissions were estimated based on changes from baseline dietary intakes that are monitored in U.S. Food and Drug Administration total diet studies. Changes from baseline intake were deemed to be proportional to the projected changes in soil or surface water metal concentrations. Human exposure to metals emitted from nine hazardous waste incinerators were then evaluated. Metal emissions from certain facilities resulted in tangible human exposure through noninhalation pathways. However, the analysis indicated that the deposition of metals from ambient air would result in substantially greater human exposure through noninhalation pathways than the emissions from most of the facilities. PMID:7925180

  7. Soil moisture feedback mediates increased carbon storage under elevated CO{sub 2}

    SciTech Connect

    Hungate, B.A.; Chapin, F.S. III; Jackson, R.B.

    1995-09-01

    After 3 years of exposure to elevated atmospheric CO{sub 2}, soil carbon increased in an extremely nutrient-limited serpentine grassland, but did not change in a more productive sandstone grassland. The increase in the serpentine shows the potential for nutrient-limited ecosystems to sequester carbon under elevated CO{sub 2}, but lack of response in the sandstone grassland suggests that increased soil carbon is not a general ecosystem response to elevated CO{sub 2}. Changes in soil moisture under elevated CO{sub 2} may explain the lack of response in the sandstone. Elevated CO{sub 2} decreases transpiration in plants from both ecosystems, but this consistently increases soil moisture only on the sandstone, where plants more strongly control evapotranspiration than on the serpentine. Increased soil moisture stimulates decomposition in these systems, potentially compensating for increased carbon input to soil under elevated CO{sub 2}, resulting in no net change in soil carbon. Increased soil moisture also stimulates plant growth directly and stimulates nitrogen mineralization and plant nitrogen uptake, potentially increasing plant production under elevated CO{sub 2}. We suggest that, in ecosystems with well developed plant canopies where increased soil moisture is likely under elevated CO{sub 2}, feedbacks through soil moisture may increase production, but may also constrain increased carbon storage in soil.

  8. Advanced Exposure Metrics For Chemical Risk Analysis: Systems Biology and 'Omic-based Biomarkers for Exposure Reconstruction

    EPA Science Inventory

    Direct measurement of human exposure to environmental contaminants in real time (when the exposure is actually occurring) is rare and difficult to obtain. This frustrates both exposure assessments and investigations into the linkage between chemical exposure and human disease. ...

  9. Military Exposures

    MedlinePlus

    ... Index Agent Orange Agent Orange Home Facts about Herbicides Veterans' Diseases Birth Defects Benefits Exposure Locations Provider ... for Providers Diagnosis and Treatment of Exposure Health Effects More Provider Resources » return to top Get Email ...

  10. Ecotoxicological evaluation of low-concentration bisphenol A exposure on the soil nematode Caenorhabditis elegans and intrinsic mechanisms of stress response in vivo.

    PubMed

    Zhou, Dong; Yang, Jie; Li, Hui; Lu, Qiang; Liu, Yong-di; Lin, Kuang-Fei

    2016-08-01

    As a representative species of nematodes, Caenorhabditis elegans is an attractive animal model for evaluating ecotoxicological effects and intrinsic mechanisms of the stress response in vivo. To acquire a better knowledge of environmental effects of bisphenol A (BPA), ecotoxicological evaluations were conducted using C. elegans on the physiological (growth, locomotion behaviors, and reproduction), biochemical (lipofuscin accumulation, reactive oxygen species production, and cell apoptosis), and molecular (stress-related gene expression) responses. Nematodes were exposed to BPA (0.001-10 µM) in 2 assay systems (L4 larvae for 24 h and L1 larvae for 72 h). Exposure to BPA could significantly (p < 0.05) alter body length, locomotion behaviors, brood size, cell apoptosis, and selected stress-related gene expression. At the physiological level, BPA exerted adverse effects on nematodes at the microgram per liter level in both assay systems, with head thrashes as the most sensitive endpoint. At the biochemical level, apoptosis degree showed increases at concentrations above 0.1 µM in both assay systems. At the molecular level, BPA induced increases in selected stress-related gene expression, even at the lowest tested concentration. In addition, BPA-induced cell apoptosis was suggested as a potential mode of action, resulting in adverse physiological effects. Therefore, BPA exposure was speculated to impose developmental, reproductive, and neurobehavioral toxicities on C. elegans and caused variations of stress-related gene expression. Environ Toxicol Chem 2016;35:2041-2047. © 2016 SETAC. PMID:26748796

  11. Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models: Current status and future directions

    SciTech Connect

    Tian, Hanqin; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Huntzinger, Deborah N.; Schwalm, Christopher R.; Michalak, Anna M.; Cook, Robert; Ciais, Philippe; Hayes, Daniel; Huang, Maoyi; Ito, Akihiko; Jain, Atul K.; Lei, Huimin; Mao, Jiafu; Pan, Shufen; Post, Wilfred M.; Peng, Shushi; Poulter, Benjamin; Ren, Wei; Ricciuto, Daniel; Schaefer, Kevin; Shi, Xiaoying; Tao, Bo; Wang, Weile; Wei, Yaxing; Yang, Qichun; Zhang, Bowen; Zeng, Ning

    2015-06-05

    Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and C loss from soil accounts for a large proportion of land-atmosphere C exchange. Therefore, a small change in soil organic C (SOC) can affect atmospheric carbon dioxide (CO₂) concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil C exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling. However, these estimates are highly uncertain, and identifying major driving forces controlling soil C dynamics remains a key research challenge. This study has compiled century-long (1901–2010) estimates of SOC storage and heterotrophic respiration (Rh) from 10 terrestrial biosphere models (TBMs) in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project and two observation-based data sets. The 10 TBM ensemble shows that global SOC estimate ranges from 425 to 2111 Pg C (1 Pg = 10¹⁵ g) with a median value of 1158 Pg C in 2010. The models estimate a broad range of Rh from 35 to 69 Pg C yr⁻¹ with a median value of 51 Pg C yr⁻¹ during 2001–2010. The largest uncertainty in SOC stocks exists in the 40–65°N latitude whereas the largest cross-model divergence in Rh are in the tropics. The modeled SOC change during 1901–2010 ranges from –70 Pg C to 86 Pg C, but in some models the SOC change has a different sign from the change of total C stock, implying very different contribution of vegetation and soil pools in determining the terrestrial C budget among models. The model ensemble-estimated mean residence time of SOC shows a reduction of 3.4 years over the past century, which accelerate C cycling through the land biosphere. All the models agreed that climate and land use changes decreased SOC stocks, while elevated atmospheric CO₂ and nitrogen deposition over intact ecosystems increased SOC stocks—even though the responses varied significantly

  12. Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models: Current status and future directions

    DOE PAGESBeta

    Tian, Hanqin; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Huntzinger, Deborah N.; Schwalm, Christopher R.; Michalak, Anna M.; Cook, Robert; Ciais, Philippe; Hayes, Daniel; et al

    2015-06-05

    Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and C loss from soil accounts for a large proportion of land-atmosphere C exchange. Therefore, a small change in soil organic C (SOC) can affect atmospheric carbon dioxide (CO₂) concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil C exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling. However, these estimates are highly uncertain, and identifying major driving forces controlling soil C dynamics remains a key research challenge. This study has compiled century-longmore » (1901–2010) estimates of SOC storage and heterotrophic respiration (Rh) from 10 terrestrial biosphere models (TBMs) in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project and two observation-based data sets. The 10 TBM ensemble shows that global SOC estimate ranges from 425 to 2111 Pg C (1 Pg = 10¹⁵ g) with a median value of 1158 Pg C in 2010. The models estimate a broad range of Rh from 35 to 69 Pg C yr⁻¹ with a median value of 51 Pg C yr⁻¹ during 2001–2010. The largest uncertainty in SOC stocks exists in the 40–65°N latitude whereas the largest cross-model divergence in Rh are in the tropics. The modeled SOC change during 1901–2010 ranges from –70 Pg C to 86 Pg C, but in some models the SOC change has a different sign from the change of total C stock, implying very different contribution of vegetation and soil pools in determining the terrestrial C budget among models. The model ensemble-estimated mean residence time of SOC shows a reduction of 3.4 years over the past century, which accelerate C cycling through the land biosphere. All the models agreed that climate and land use changes decreased SOC stocks, while elevated atmospheric CO₂ and nitrogen deposition over intact ecosystems increased SOC stocks—even though the responses varied

  13. Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models: Current status and future directions

    NASA Astrophysics Data System (ADS)

    Tian, Hanqin; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Huntzinger, Deborah N.; Schwalm, Christopher R.; Michalak, Anna M.; Cook, Robert; Ciais, Philippe; Hayes, Daniel; Huang, Maoyi; Ito, Akihiko; Jain, Atul K.; Lei, Huimin; Mao, Jiafu; Pan, Shufen; Post, Wilfred M.; Peng, Shushi; Poulter, Benjamin; Ren, Wei; Ricciuto, Daniel; Schaefer, Kevin; Shi, Xiaoying; Tao, Bo; Wang, Weile; Wei, Yaxing; Yang, Qichun; Zhang, Bowen; Zeng, Ning

    2015-06-01

    Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and C loss from soil accounts for a large proportion of land-atmosphere C exchange. Therefore, a small change in soil organic C (SOC) can affect atmospheric carbon dioxide (CO2) concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil C exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling. However, these estimates are highly uncertain, and identifying major driving forces controlling soil C dynamics remains a key research challenge. This study has compiled century-long (1901-2010) estimates of SOC storage and heterotrophic respiration (Rh) from 10 terrestrial biosphere models (TBMs) in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project and two observation-based data sets. The 10 TBM ensemble shows that global SOC estimate ranges from 425 to 2111 Pg C (1 Pg = 1015 g) with a median value of 1158 Pg C in 2010. The models estimate a broad range of Rh from 35 to 69 Pg C yr-1 with a median value of 51 Pg C yr-1 during 2001-2010. The largest uncertainty in SOC stocks exists in the 40-65°N latitude whereas the largest cross-model divergence in Rh are in the tropics. The modeled SOC change during 1901-2010 ranges from -70 Pg C to 86 Pg C, but in some models the SOC change has a different sign from the change of total C stock, implying very different contribution of vegetation and soil pools in determining the terrestrial C budget among models. The model ensemble-estimated mean residence time of SOC shows a reduction of 3.4 years over the past century, which accelerate C cycling through the land biosphere. All the models agreed that climate and land use changes decreased SOC stocks, while elevated atmospheric CO2 and nitrogen deposition over intact ecosystems increased SOC stocks—even though the responses varied significantly among models. Model

  14. Impacts of short-term acid and aluminum exposure on Atlantic salmon (Salmo salar) physiology: A direct comparison of parr and smolts

    USGS Publications Warehouse

    Monette, M.Y.; McCormick, S.D.

    2008-01-01

    Episodic acidification resulting in increased acidity and inorganic aluminum (Ali) is known to impact anadromous salmonids and has been identified as a possible cause of Atlantic salmon population decline. Sensitive life-stages such as smolts may be particularly vulnerable to impacts of short-term (days–week) acid/Al exposure, however the extent and mechanism(s) of this remain unknown. To determine if Atlantic salmon smolts are more sensitive than parr to short-term acid/Al, parr and smolts held in the same experimental tanks were exposed to control (pH 6.3–6.6, 11–37 μg l−1 Ali) and acid/Al (pH 5.0–5.4, 43–68 μg l−1 Ali) conditions in the lab, and impacts on ion regulation, stress response and gill Al accumulation were examined after 2 and 6 days. Parr and smolts were also held in cages for 2 and 6 days in a reference (Rock River, RR) and an acid/Al-impacted tributary (Ball Mountain Brook, BMB) of the West River in Southern Vermont. In the lab, losses in plasma Cl− levels occurred in both control parr and smolts as compared to fish sampled prior to the start of the study, however smolts exposed to acid/Al experienced additional losses in plasma Cl− levels (9–14 mM) after 2 and 6 days, and increases in plasma cortisol (4.3-fold) and glucose (2.9-fold) levels after 6 days, whereas these parameters were not significantly affected by acid/Al in parr. Gill Na+,K+-ATPase (NKA) activity was not affected by acid/Al in either life-stage. Both parr and smolts held at BMB (but not RR) exhibited declines in plasma Cl−, and increases in plasma cortisol and glucose levels; these differences were significantly greater in smolts after 2 days but similar in parr and smolts after 6 days. Gill NKA activity was reduced 45–54% in both life-stages held at BMB for 6 days compared to reference fish at RR. In both studies, exposure to acid/Al resulted in gill Al accumulation in parr and smolts, with parr exhibiting two-fold greater gill Al than smolts after 6

  15. Comparison between direct measurements and modeled estimates of external radiation exposure among school children 18 to 30 months after the Fukushima nuclear accident in Japan.

    PubMed

    Nomura, Shuhei; Tsubokura, Masaharu; Hayano, Ryugo; Furutani, Tomoyuki; Yoneoka, Daisuke; Kami, Masahiro; Kanazawa, Yukio; Oikawa, Tomoyoshi

    2015-01-20

    After a major radioactive incident, accurate dose reconstruction is important for evaluating health risks and appropriate radiation protection policies. After the 2011 Japan Fukushima nuclear incident, we assessed the level of agreement between the modeled and directly measured dose and estimated the uncertainties. The study population comprised 520 school children from Minamisoma city, located 20 km north of the nuclear plant. The annual dose 18–30 months after the incident was assessed using two approaches: estimation using the model proposed by the Japanese government and direct measurement by radiation dosemeters. The ratio of the average of modeled and measured doses was 3.0 (standard deviation (SD): 2.0). The reduction coefficient, an index for radiation attenuation properties, was 0.3 (SD: 0.1) on average, whereas the value used in the government model was 0.6. After adjusting for covariates, the coefficient had a significant negative correlation with the air dose rate in the dwelling location (p < 0.001), indicating that stronger building shielding effects are valuable in areas with higher air contamination levels. The present study demonstrated that some overestimation may have been related to uncertainties in radiation reduction effects, and that the air contamination level might provide a more important indicator of these effects. PMID:25514624

  16. Exposure to atmospheric radon.

    PubMed Central

    Steck, D J; Field, R W; Lynch, C F

    1999-01-01

    We measured radon (222Rn) concentrations in Iowa and Minnesota and found that unusually high annual average radon concentrations occur outdoors in portions of central North America. In some areas, outdoor concentrations exceed the national average indoor radon concentration. The general spatial patterns of outdoor radon and indoor radon are similar to the spatial distribution of radon progeny in the soil. Outdoor radon exposure in this region can be a substantial fraction of an individual's total radon exposure and is highly variable across the population. Estimated lifetime effective dose equivalents for the women participants in a radon-related lung cancer study varied by a factor of two at the median dose, 8 mSv, and ranged up to 60 mSv (6 rem). Failure to include these doses can reduce the statistical power of epidemiologic studies that examine the lung cancer risk associated with residential radon exposure. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:9924007

  17. Development of soil taxation and soil classification as furthered by the Austrian Soil Science Society

    NASA Astrophysics Data System (ADS)

    Baumgarten, Andreas

    2013-04-01

    Soil taxation and soil classification are important drivers of soil science in Austria. However, the tasks are quite different: whereas soil taxation aims at the evaluation of the productivity potential of the soil, soil classification focusses on the natural development and - especially nowadays - on functionality of the soil. Since the foundation of the Austrian Soil Science Society (ASSS), representatives both directions of the description of the soil have been involved in the common actions of the society. In the first years it was a main target to improve and standardize field descriptions of the soil. Although both systems differ in the general layout, the experts should comply with identical approaches. According to this work, a lot of effort has been put into the standardization of the soil classification system, thus ensuring a common basis. The development, state of the art and further development of both classification and taxation systems initiated and carried out by the ASSS will be shown.

  18. Bioavailability Of Arsenic In Arsenical Pesticide-Amended Soils: Preliminary Greenhouse Study

    NASA Astrophysics Data System (ADS)

    Quazi, S.; Sarkar, D.; Khairom, A.; Datta, R.; Sharma, S.

    2005-05-01

    Long-term application of arsenical pesticides in agricultural lands has resulted in high levels of arsenic (As). Conversion of former agricultural lands to residential areas has resulted in increased human contact with soil As. Soil ingestion from incidental hand-to-mouth activity by children is now a very important issue in assessing human health risk associated with exposure to arsenical pesticide-applied former agricultural soils. Human health risk from direct exposure to soil As via hand to mouth action is restricted only to those fractions of As in the soil that are available to the human gastrointestinal system. Thus this study aimed at addressing the issue of soil variability on As bioavailability as a function of soil physiochemical properties in a dynamic interaction between soils, water and plants and pesticides. In the current greenhouse study two soils with drastically different chemical characteristics w.r.t As reactivity (Immokalee-low As retention potential and Millhopper-high As retention potential) and one pesticide (sodium arsenate) were used. Soils were amended with sodium arsenate at two rates representing the high and low ends of As contamination, generally representative of Superfunds site conditions: 675 and 1500 mg/kg As. Rice (Oryza sativa) was used as the test crop. Sequential digestion to estimate in-vitro As in the stomach phase and the intestinal phase was employed on soils sampled at 4 times: 0-time, after 3 mo, 6 mo and 9 mo of soil-pesticide equilibration. In-vitro bioavailability experiments were also performed with the same soils in order to obtain an estimate of the amount of As that would be absorbed to the intestinal linings in simulated systems. Following the greenhouse study, selective in-vivo bioavailability studies using As-contaminated soils will be conducted on male and female mice to correlate in-vitro results with the in-vivo data. Treatments will consist of a soil group (As in soil), a positive control group (only As

  19. Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models. Current status and future directions

    SciTech Connect

    Tian, Hanqin; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Huntzinger, Deborah N.; Schwalm, Christopher R.; Michalak, A. M.; Cook, Robert B.; Ciais, Philippe; Hayes, Daniel J.; Huang, Maoyi; Ito, Akihiko; Jain, Atul K.; Lei, Huimin; Mao, Jiafu; Pan, Shufen; Post, W. M.; Peng, Shushi; Poulter, Benjamin; Ren, Wei; Ricciuto, Daniel M.; Schaefer, Kevin; Shi, Xiaoying; Tao, Bo; Wang, Weile; Wei, Yaxing; Yang, Qichun; Zhang, Bowen; Zeng, Ning

    2015-06-05

    Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and loss from soil accounts for a large pro portion of land-atmosphere C exchange. Due to large pool size and variable residence time from years to millennia, even small changes in soil organic C(SOC) have substantial effects on the terrestrial C budget, thereby affecting atmospheric carbon dioxide (CO2)concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling. However, these estimates are highly uncertain and identifying major driving forces controlling soil C storage and fluxes remains a key research challenge his study has compiled century-long (1901-2010)estimates of SOC storage and heterotrophic respiration (Rh) from ten terrestrial biosphere models (TBMs) in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) and two observation based datasets. The ten-TBM ensemble shows that global SOC estimate range from 4 to 2111 Pg C (1 Pg = 1015g) with a median value of 1158 Pg C33 in 2010. Modeling approach estimates a broad range of Rh from 35 to 69 Pg C yr-1 with a median value of 51Pg C yr-1 during 200–2010. The largest uncertainty in SOC stocks exists in the 40–65°N latitude band while Rh differences are the largest in the tropics. All the models agreed that climate and land use changes have decreased SOC stocks while elevated CO2 and atmospheric nitrogen deposition have increased SOC stocks though the response varied significantly among models. Model representations of temperature and moisture sensitivity,nutrient limitation and land use partially explain the divergent estimates of global SOC stocks and soil fluxes in this study. In addition, major sources of uncertainty from model estimation include exclusion of SOC storage in

  20. Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells

    NASA Astrophysics Data System (ADS)

    Hassen, Diab; El-Safty, Sherif A.; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed. A.; Sakai, Masaru

    2016-04-01

    Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes.

  1. Occupational arsine gas exposure.

    PubMed Central

    Pullen-James, Shayla; Woods, Scott E.

    2006-01-01

    Arsine gas exposure is a rare occupational event and can be completely prevented with the use of appropriate protective gear. Exposure often occurs when arsine gas is generated while arsenic-containing crude ores or metals are treated with acid. Cases of toxicity require an index of suspicion and a good history. In particular, it should be in the differential diagnosis in patients who present acutely with red/bronze skin and hemoglobinuria. Treatment is supportive and may include transfusions and dialysis in severe cases. Clinical severity is proportionate to the level of exposure, and severity is directly related to the onset of symptoms. Images Figure 2 PMID:17225850

  2. Analysis of aggregate exposure to chlorpyrifos in the NHEXAS-Maryland investigation.

    PubMed Central

    Pang, Yaohong; MacIntosh, David L; Camann, David E; Ryan, P Barry

    2002-01-01

    As part of the National Human Exposure Assessment Survey (NHEXAS) in Maryland, we collected indoor air, carpet dust, exterior soil, and duplicate diet samples from a stratified random sample of 80 individuals to evaluate aggregate daily exposure, contributions of specific pathways of exposure, and temporal variation in exposure to chlorpyrifos. We collected samples from each participant in up to six equally spaced sampling cycles over a year and analyzed them for chlorpyrifos. We used chlorpyrifos concentrations in each medium and self-reported rates of time spent inside at home, time and frequency of contact with carpet, frequency of contact with soil, and weights of the duplicate diet samples to derive exposure to chlorpyrifos from each medium as well as average daily aggregate exposure (nanograms per day). The mean aggregate daily exposure to chlorpyrifos of 36 measurements obtained from 31 people was 1,390 ng/day (SD, 2,770 ng/day). Exposure from inhalation of indoor air accounted for 84.7% of aggregate daily exposure to chlorpyrifos on average. Chlorpyrifos concentrations in indoor air and carpet dust and the corresponding exposure rates were significantly correlated. Repeated short-term measurements of chlorpyrifos in carpet dust from individual residences were strongly correlated over time (reliability coefficient, R = 0.90), whereas the short-term measurements of chlorpyrifos in indoor air (R = 0.55) and solid food (R = 0.03) had moderate to weak reliability. Exposure to chlorpyrifos through those media and in aggregate based on direct measurements reported in this study can be used to understand better the accuracy of pesticide safety assessments. PMID:11882473

  3. Effect of wetting-drying cycles and fire conditions on runoff and soil loss of a Mediterranean Pale Rendzina

    NASA Astrophysics Data System (ADS)

    Lado, Marcos; Inbar, Assaf; Tenaw, Haim; Stenberg, Marcelo; Ben-Hur, Meni

    2013-04-01

    Wetting and drying cycles have been reported to have a positive effect on soil aggregation and improve the recovery of soil structure after a disturbance. Therefore, after wildfires, it is expected that drying periods between consecutive storms could modify runoff and soil loss patterns. At the same time, different fire conditions may coexist in a location during a wildfire, creating a mosaic of soils affected to different degrees. The objective of this study was to analyze the effect of wetting-drying cycles and various fire conditions on infiltration rate, runoff and soil loss of a Mediterranean soil. Samples from a Pale Rendzina from Birya forest in Northern Israel were subjected to treatments representing some of the soil disturbances that may coexist after a wildfire: unburnt (UB-soil, i.e. not affected by fire); low-moderate severity direct fire (direct fire-DF soil) and; prolonged heating under moderate temperature without direct contact with the flames (oven heated-HT soil). Each soil was placed under a rainfall simulator and exposed to three 80-mm storms separated by drying periods of 72h. Significant differences were found between fire conditions in infiltration rate, runoff and soil loss. Runoff and soil loss were in the following order :HTsoil loss of the HT soil were a result of its higher structural stability, likely emerging from the thermal fusion of clay particles in the aggregates, and from changes in the soil solution that reduced clay dispersion. This was confirmed by data obtained from slaking and dispersion tests. Wetting and drying cycles did not have a positive effect on runoff or soil loss. Total runoff and soil loss from the UB soil remained relatively constant in the three rainstorms, while those of DF and HT soils increased significantly from one rainstorm to the next. Therefore, the differences between fire conditions became smaller as the number of

  4. Measurements of natural radionuclides in human teeth and animal bones as markers of radiation exposure from soil in the Northern Malaysian Peninsula

    NASA Astrophysics Data System (ADS)

    Almayahi, B. A.; Tajuddin, A. A.; Jaafar, M. S.

    2014-04-01

    This study aimed to estimate the radioactive accumulation of the radionuclides 40K, 137Cs, 210Pb, 226Ra, 228Ra, and 228Th in extracted human teeth, animal bones, and soil. The natural radionuclides were measured by high-purity germanium spectroscopy in extracted human teeth and animal bones from people and animals living in different states in the Northern Malaysian Peninsula. The average 40K, 137Cs, 210Pb, 226Ra, 228Ra, and 228Th concentrations in teeth were found to be 12.31±7.27 Bq g-1, 0.48±0.21 Bq g-1, 0.56±0.21 Bq g-1, 0.55±0.23 Bq g-1, 1.82±1.28 Bq g-1, and 0.50±0.14 Bq g-1, respectively. The corresponding concentrations in bones were found to be 3.79±0.81 Bq g-1, 0.07±0.02 Bq g-1, 0.08±0.02 Bq g-1, 0.16±0.04 Bq g-1, 0.51±1.08 Bq g-1, and 0.06±0.02 Bq g-1, respectively. The corresponding radionuclide concentrations in teeth from smokers were higher than those in non-smokers, and the corresponding radionuclide concentrations were higher in female teeth than in male teeth. The corresponding radionuclide concentrations were higher in teeth than in bones. A positive correlation was found between radionuclides in both teeth and bone samples.

  5. Exposure chamber

    DOEpatents

    Moss, Owen R.

    1980-01-01

    A chamber for exposing animals, plants, or materials to air containing gases or aerosols is so constructed that catch pans for animal excrement, for example, serve to aid the uniform distribution of air throughout the chamber instead of constituting obstacles as has been the case in prior animal exposure chambers. The chamber comprises the usual imperforate top, bottom and side walls. Within the chamber, cages and their associated pans are arranged in two columns. The pans are spaced horizontally from the walls of the chamber in all directions. Corresponding pans of the two columns are also spaced horizontally from each other. Preferably the pans of one column are also spaced vertically from corresponding pans of the other column. Air is introduced into the top of the chamber and withdrawn from the bottom. The general flow of air is therefore vertical. The effect of the horizontal pans is based on the fact that a gas flowing past the edge of a flat plate that is perpendicular to the flow forms a wave on the upstream side of the plate. Air flows downwardly between the chamber walls and the outer edges of the pan. It also flows downwardly between the inner edges of the pans of the two columns. It has been found that when the air carries aerosol particles, these particles are substantially uniformly distributed throughout the chamber.

  6. Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells.

    PubMed

    Hassen, Diab; El-Safty, Sherif A; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed A; Sakai, Masaru

    2016-01-01

    Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes. PMID:27075551

  7. Alarmingly High Segregation Frequencies of Quinolone Resistance Alleles within Human and Animal Microbiomes Are Not Explained by Direct Clinical Antibiotic Exposure

    PubMed Central

    Field, Wesley; Hershberg, Ruth

    2015-01-01

    Antibiotic resistance poses a major threat to human health. It is therefore important to characterize the frequency of resistance within natural bacterial environments. Many studies have focused on characterizing the frequencies with which horizontally acquired resistance genes segregate within natural bacterial populations. Yet, very little is currently understood regarding the frequency of segregation of resistance alleles occurring within the housekeeping targets of antibiotics. We surveyed a large number of metagenomic datasets extracted from a large variety of host-associated and non host-associated environments for such alleles conferring resistance to three groups of broad spectrum antibiotics: streptomycin, rifamycins, and quinolones. We find notable segregation frequencies of resistance alleles occurring within the target genes of each of the three antibiotics, with quinolone resistance alleles being the most frequent and rifamycin resistance alleles being the least frequent. Resistance allele frequencies varied greatly between different phyla and as a function of environment. The frequency of quinolone resistance alleles was especially high within host-associated environments, where it averaged an alarming ∼40%. Within host-associated environments, resistance to quinolones was most often conferred by a specific resistance allele. High frequencies of quinolone resistance alleles were also found within hosts that were not directly treated with antibiotics. Therefore, the high segregation frequency of quinolone resistance alleles occurring within the housekeeping targets of antibiotics in host-associated environments does not seem to be the sole result of clinical antibiotic usage. PMID:26019163

  8. Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells

    PubMed Central

    Hassen, Diab; El-Safty, Sherif A.; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed. A.; Sakai, Masaru

    2016-01-01

    Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes. PMID:27075551

  9. Bioavailability of soil-adsorbed cadmium in orally exposed male rats.

    PubMed Central

    Schilderman, P A; Moonen, E J; Kempkers, P; Kleinjans, J C

    1997-01-01

    Cd excreted into urine of the Cd-soil group during the experimental period corresponded to only 0.01% of the original dose. In the Cd-saline group, no additional Cd was excreted into urine as compared to the control group. These results indicate that the soil matrix significantly reduced the absorption of Cd in the gastrointestinal tract. Consequently, exposure assessment models, assuming an unaffected bioavailability of soil-absorbed Cd, overestimate the internal dose and thereby overestimate health risks associated with direct ingestion of soil particles. Images Figure 1. PMID:9105799

  10. Microwave backscatter dependence on surface roughness, soil moisture, and soil texture. II - Vegetation-covered soil

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Bradley, G. A.; Dobson, M. C.

    1979-01-01

    Results are presented for an experimental investigation to determine the relationship between radar backscatter coefficient (sigma) and soil moisture for vegetation-covered soil. These results extend a previous report which showed the experimental relationship between sigma and soil moisture for bare soil. It is shown that the highest correlation between sigma and soil moisture is 0.92 for the combined response of four crop types measured at 4.25 GHz, 10 deg incidence angle, and HH polarization. Radar look direction, relative to the crop row direction, is shown to have an insignificant effect on soil-moisture estimation if the radar frequency is higher than 4 GHz. The dependence on soil type can be minimized by expressing soil moisture in units of percent of field capacity. The possibility of using a single radar for measuring soil moisture for both bare and vegetated fields is demonstrated with a linear estimation algorithm having an experimental correlation coefficinet of 0.8.

  11. Risk Information Exposure and Direct to Consumer Genetic Testing for BRCA Mutations among Women with a Personal or Family History of Breast or Ovarian Cancer

    PubMed Central

    Gray, Stacy W.; O’Grady, Cristin; Karp, Lauren; Smith, Daniel; Schwartz, J. Sanford; Hornik, Robert C.; Armstrong, Katrina

    2009-01-01

    Background Direct to consumer (DTC) BRCA testing may expand access to genetic testing and enhance cancer prevention efforts. However, it is not know if current DTC websites provide adequate risk information for informed medical decision-making. Methods 284 women with a personal or family history of breast/ovarian cancer were randomly assigned to view a “mock” DTC commercial website (control condition: CC, n=93) or the same “mock” website that included information on the potential risks of obtaining genetic testing online. Risk information was framed two ways: risk information attributed to expert sources (ES, n=98) and unattributed risk information (URI, n=93). Participants completed an online survey. Endpoints were intentions to get BRCA testing, testing site preference and beliefs about DTC BRCA testing. Results Sample characteristics: mean age 39 (range 18–70), 82% white, mean education 3 yrs. college. Women exposed to risk information had lower intentions to get BRCA testing than women in the CC (adjusted odds ratio (OR) 0.48; 95% confidence interval (CI) 0.26–0.87, p=0.016), less positive beliefs about online BRCA testing (adjusted OR 0.48; 95% 0.27–0.86, p=0.014). Women in the ES condition were more likely to prefer clinic based testing than women in the CC (adjusted OR 2.05; 95% CI 1.07–3.90, p=0.030). Conclusion Exposing women to information on the potential risks of online BRCA testing altered their intentions, beliefs and preferences for BRCA testing. Policy makers may want to consider content and framing of risk information on DTC websites as they formulate regulation for this rapidly growing industry. PMID:19318436

  12. Field measurement of dermal soil loadings in occupational and recreational activities

    SciTech Connect

    Holmes, K.K. Jr.; Shirai, J.H.; Richter, K.Y.; Kissel, J.C.

    1999-02-01

    Risks associated with dermal exposure to contaminated soil are not well-characterized, but nevertheless must be estimated to define endpoints for remedial strategies. Among the parameters contributing to the uncertainty of these estimates is soil adherence to skin. Pre- and postactivity soil loadings have been obtained from hands, forearms, lower legs, faces, and/or feet of volunteers engaged in various occupational and recreational activities. These data are distinguished from other sources of estimates of soil adherence by the manner of their collection. Soil loads were obtained directly from multiple body parts before and after uncontrived exposure scenarios. Data presented for the first time here supplement prior results and roughly double the available data base. This expanded data base provides a useful perspective on types of behavior likely to lead to soil contact falling within general classes of activity. Prior conclusions supported by the additional data include the following: (1) post-activity loadings are typically higher than preactivity levels, demonstrating that exposure is episodic; (2) hand loadings are dependent upon class of activity; (3) hand loadings generally provide conservative estimates of loadings on nonhand body parts within activity classes; and (4) hand loadings do not provide conservative estimates of nonhand loadings across activity classes. Finally quantitative estimates of relative loads on unclothed nonhand body parts are presented.

  13. Direct effects of soil amendments on field emergence and growth of the invasive annual grass Bromus tectorum L. and the native perennial grass Hilaria jamesii (Torr.) Benth

    USGS Publications Warehouse

    Newingham, B.A.; Belnap, J.

    2006-01-01

    Bromus tectorum L. is a non-native, annual grass that has invaded western North America. In SE Utah, B. tectorum generally occurs in grasslands dominated by the native perennial grass, Hilaria jamesii (Torr.) Benth. and rarely where the natives Stipa hymenoides Roem. and Schult. and S. comata Trin. & Rupr. are dominant. This patchy invasion is likely due to differences in soil chemistry. Previous laboratory experiments investigated using soil amendments that would allow B. tectorum to germinate but would reduce B. tectorum emergence without affecting H. jamesii. For this study we selected the most successful treatments (CaCl2, MgCl2, NaCl and zeolite) from a previous laboratory study and applied them in the field in two different years at B. tectorum-dominated field sites. All amendments except the lowest level of CaCl2 and zeolite negatively affected B. tectorum emergence and/or biomass. No amendments negatively affected the biomass of H. jamesii but NaCl reduced emergence. Amendment effectiveness depended on year of application and the length of time since application. The medium concentration of zeolite had the strongest negative effect on B. tectorum with little effect on H. jamesii. We conducted a laboratory experiment to determine why zeolite was effective and found it released large amounts of Na+, adsorbed Ca2+, and increased Zn2+, Fe2+, Mn2+, Cu2+, exchangeable Mg2+, exchangeable K, and NH 4+ in the soil. Our results suggest several possible amendments to control B. tectorum. However, variability in effectiveness due to abiotic factors such as precipitation and soil type must be accounted for when establishing management plans. ?? Springer 2006.

  14. Cross calibration of AGFA-D7 x-ray film against direct exposure film from 2 to 8.5 keV using laser generated x-rays

    NASA Astrophysics Data System (ADS)

    Kyrala, George A.

    2006-05-01

    Direct exposure film (DEF) is being discontinued. DEF film has been the workhorse in inertial confinement fusion (ICF) research and is used to record x-ray images and spectra. A previous search for a replacement [K. M. Chandler et al., Rev. Sci. Instrum. 76, 113111 (2005)] did not consider AGFA film. We present comparisons using the results of measurements using AGFA-D7 film, XAR, TMG, and Biomax-MS films in the same spectrometer recording a gold spectrum in the 2-4keV range and the iron spectrum in the 5-8.5keV range. AGFA film was found to have some unique properties useful in x-ray spectroscopy and imaging, especially when signal strength is not a concern.

  15. Occupational exposure in MRI.

    PubMed

    McRobbie, D W

    2012-04-01

    This article reviews occupational exposure in clinical MRI; it specifically considers units of exposure, basic physical interactions, health effects, guideline limits, dosimetry, results of exposure surveys, calculation of induced fields and the status of the European Physical Agents Directive. Electromagnetic field exposure in MRI from the static field B(0), imaging gradients and radiofrequency transmission fields induces electric fields and currents in tissue, which are responsible for various acute sensory effects. The underlying theory and its application to the formulation of incident and induced field limits are presented. The recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Bundesministerium für Arbeit und Soziales and Institute of Electrical and Electronics Engineers limits for incident field exposure are interpreted in a manner applicable to MRI. Field measurements show that exposure from movement within the B(0) fringe field can exceed ICNIRP reference levels within 0.5 m of the bore entrance. Rate of change of field dB/dt from the imaging gradients is unlikely to exceed the new limits, although incident field limits can be exceeded for radiofrequency (RF) exposure within 0.2-0.5 m of the bore entrance. Dosimetric surveys of routine clinical practice show that staff are exposed to peak values of 42 ± 24% of B(0), with time-averaged exposures of 5.2 ± 2.8 mT for magnets in the range 0.6-4 T. Exposure to time-varying fields arising from movement within the B(0) fringe resulted in peak dB/dt of approximately 2 T s(-1). Modelling of induced electric fields from the imaging gradients shows that ICNIRP-induced field limits are unlikely to be exceeded in most situations; however, movement through the static field may still present a problem. The likely application of the limits is discussed with respect to the reformulation of the European Union (EU) directive and its possible implications for MRI. PMID:22457400

  16. Soil Genesis and Development, Lesson 4 - Soil Profile Development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The history of a soil is reflected in the arrangement of its constituent parts. Largely the arrangement is related to the movement, or lack of movement, of water through the soil in all directions. Understanding the processes that result in a specific soil type allows for more precise and effectiv...

  17. Abiotic soil changes induced by engineered nanomaterials: A critical review.

    PubMed

    Dror, Ishai; Yaron, Bruno; Berkowitz, Brian

    2015-10-01

    A large number of research papers on the fate of engineered nanomaterials (ENMs) in the soil-water system have appeared in recent years, focusing on ENM transport, persistence and toxicological impact. It is clear from these publications that soil is a major sink for ENMs, and that only a small portion degrades or is mobilized further into groundwater. However, to date, very few studies have examined the impact of ENMs on the natural soil-subsurface matrix and its properties. Moreover, it is now well accepted that chemical contaminants are capable of changing soil properties either by inducing direct chemical or physical changes, or through indirect changes by, e.g., influencing biological activity that in turn modifies soil properties. Here, we review studies on the deposition, retention, and accumulation of ENMs in soil, indicative of the extent to which soil acts as a major sink of ENMs. We then examine evidence of how these retained particles lead to modification of surface properties, which are manifested by changes in the sorption capacity of soil for other (organic and inorganic) solutes, and by surface charges and composition different than the natural surfaces. Finally, we demonstrate how this results in physical and hydrological changes to soil properties, including hydraulic conductivity, swelling capacity and wettability. The overall picture revealed in this critical review sheds light on a perspective that has received little attention thus far. These aspects of soil change, due to exposure and subsequent accumulation of ENMs, may ultimately prove to be one of the most important impacts of ENM releases to the environment. PMID:25913535

  18. A tiered approach for assessing children's exposure.

    PubMed Central

    Armstrong, T W; Hushka, L J; Tell, J G; Zaleski, R T

    2000-01-01

    Recently, intense attention has been given to children's health issues, particularly in the use of consumer products. Because of this attention, researchers have been planning and initiating studies specifically aimed at developing both toxicology data and exposure data directed to improve our understanding of industrial and consumer product chemical impacts on children's health. To ensure that this research is focused on the highest priority chemicals, we present a methodology for determining and prioritizing the higher hazard chemicals and scenarios for which children could be disproportionately or highly exposed. This tiered approach includes a screening step for initial chemical selection, a hazard assessment based on no- or lowest-observed-adverse-effect levels, and a margin of exposure (MOE) calculation. The initial chemical screen focuses on the chemical presence in specific media that are special to children, such as foods children regularly eat and drink, residential or school air, products children use, and soil and dust in and around residences. Data from the literature or from models serve as the initial exposure estimate. This methodology would allow us to focus on those chemicals to which children are most exposed that are also associated with, potentially, the highest risk. Use of the MOE calculation allows for comparison among chemicals, prioritization of chemicals for evaluation and testing, and identification of significant data gaps. PMID:10856018

  19. Stability of Biochar in Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conversion of biomass to biochar followed by application of the biochar to the soil increases the residence time of carbon (C) in the soil relative to application of the same biomass directly to the soil, and therefore can be considered over particular timescales to result in a net withdrawal of atm...

  20. Relative bioavailability of arsenic contaminated soils in a mouse model

    EPA Science Inventory

    Exposure to As contaminated soils compels extensive soil cleanups so that human health risks are minimized. In order to improve exposure estimates and potentially reduce remediation costs, determination of the bioavailability of As in soils is needed. The objective of this study ...

  1. ATMOSPHERIC BENZENE DEPLETION BY SOIL MICROORGANISMS

    EPA Science Inventory

    Gaseous benzene was rapidly depleted in exposure chambers containing viable soils and plants. When separate components of the system were analyzed, no benzene was detected in soils, plants, or water. Soil microorganisms were shown to be responsible for metabolizing benzene, yield...

  2. A Reactive Transport Model for the Distribution and Age of Carbon in Soils and Sediments Through Direct Simulation of the Stable and Radiogenic Isotopologues

    NASA Astrophysics Data System (ADS)

    Druhan, J. L.; Lawrence, C. R.

    2015-12-01

    We present a reactive transport (RT) approach to link hydrologic transport, geochemical transformations and microbial activity influencing the magnitude and residence time of different carbon pools under variably saturated conditions. This model explicitly simulates the simultaneous transport, transformation, fractionation and decay of the three isotopes of carbon (12C, 13C and 14C) through a mechanistic framework. This is demonstrated with a modification of the CrunchTope multi-component RT software to extend the isotope-specific versions of both microbially-mediated and transition state theory (TST) rate laws to accommodate a three-isotope system. In addition both aqueous and solid phase decay of 14C are tracked, yielding in an implicit means of accounting for the 13C/12C correction in normalized radiocarbon ages. The capacity of this approach to quantify the storage and flux of carbon through subsurface compartments is demonstrated using two examples distinguished by timescale. The first considers a simplified flow path in which an influent containing labile organic carbon is distributed by biogenic reduction and mineralization into a suite of reaction products. The residence time of these pools and their characteristic stable isotope ratios are tracked through a variety of transient processes occurring at short timescales (e.g. months). These include a change in fluid flow rate, a limitation of ammonium supporting anabolic growth and an influx of oxygenated fluid. The second example considers the distribution of carbon over the timescale of soil development (e.g., millennia), using a dataset of stable isotope ratios and radiocarbon ages of organic and inorganic carbon present in both dissolved and solid phases from a soil chronosequence near Santa Cruz, CA. The results of these model simulations suggest the promise of this tool for improving our understanding of coupling between hydrologic transport and biogeochemical reactions in soils.

  3. Dermal exposure assessment techniques.

    PubMed

    Fenske, R A

    1993-12-01

    Exposure of the skin to chemical substances can contribute significantly to total dose in many workplace situations, and its relative importance will increase when airborne occupational exposure limits are reduced, unless steps to reduce skin exposure are undertaken simultaneously. Its assessment employs personal sampling techniques to measure skin loading rates, and combines these measurements with models of percutaneous absorption to estimate absorbed dose. Knowledge of dermal exposure pathways is in many cases fundamental to hazard evaluation and control. When the skin is the primary contributor to absorbed dose, dermal exposure measurements and biological monitoring play complementary roles in defining occupational exposures. Exposure normally occurs by one of three pathways: (i) immersion (direct contact with a liquid or solid chemical substance); (ii) deposition of aerosol or uptake of vapour through the skin; or (iii) surface contact (residue transfer from contaminated surfaces). Sampling methods fall into three categories: surrogate skin; chemical removal; and fluorescent tracers. Surface sampling represents a supplementary approach, providing an estimate of dermal exposure potential. Surrogate skin techniques involve placing a chemical collection medium on the skin. Whole-body garment samplers do not require assumptions relating to distribution, an inherent limitation of patch sampling. The validity of these techniques rests on the ability of the sampling medium to capture and retain chemicals in a manner similar to skin. Removal techniques include skin washing and wiping, but these measure only what can be removed from the skin, not exposure: laboratory removal efficiency studies are required for proper interpretation of data. Fluorescent tracer techniques exploit the visual properties of fluorescent compounds, and combined with video imaging make quantification of dermal exposure patterns possible, but the need to introduce a chemical substance (tracer

  4. Soil in the Anthropocene

    NASA Astrophysics Data System (ADS)

    Richter, Daniel deB; Bacon, Allan R.; Brecheisen, Zachary; Mobley, Megan L.

    2015-07-01

    With scholars deliberating a new name for our geologic epoch, i.e., the Anthropocene, soil scientists whether biologists, chemists, or physicists are documenting significant changes accruing in a majority of Earth's soils. Such global soil changes interact with the atmosphere, biosphere, hydrosphere, and lithosphere (i.e., Earth's Critical Zone), and these developments are significantly impacting the Earth's stratigraphic record as well. In effect, soil scientists study such global soil changes in a science of anthropedology, which leads directly to the need to transform pedostratigraphyinto an anthro-pedostratigraphy, a science that explores how global soil change alters Earth's litho-, bio-, and chemostratigraphy. These developments reinforce perspectives that the planet is indeed crossing into the Anthropocene.

  5. Effects of Silver Nanoparticle Exposure on Germination and Early Growth of Eleven Wetland Plants

    PubMed Central

    Yin, Liyan; Colman, Benjamin P.; McGill, Bonnie M.; Wright, Justin P.; Bernhardt, Emily S.

    2012-01-01

    The increasing commercial production of engineered nanoparticles (ENPs) has led to concerns over the potential adverse impacts of these ENPs on biota in natural environments. Silver nanoparticles (AgNPs) are one of the most widely used ENPs and are expected to enter natural ecosystems. Here we examined the effects of AgNPs on germination and growth of eleven species of common wetland plants. We examined plant responses to AgNP exposure in simple pure culture experiments (direct exposure) and for seeds planted in homogenized field soils in a greenhouse experiment (soil exposure). We compared the effects of two AgNPs–20-nm polyvinylpyrrolidine-coated silver nanoparticles (PVP-AgNPs) and 6-nm gum arabic coated silver nanoparticles (GA-AgNPs)–to the effects of AgNO3 exposure added at equivalent Ag concentrations (1, 10 or 40 mg Ag L−1). In the direct exposure experiments, PVP-AgNP had no effect on germination while 40 mg Ag L−1 GA-AgNP exposure significantly reduced the germination rate of three species and enhanced the germination rate of one species. In contrast, 40 mg Ag L−1 AgNO3 enhanced the germination rate of five species. In general root growth was much more affected by Ag exposure than was leaf growth. The magnitude of inhibition was always greater for GA-AgNPs than for AgNO3 and PVP-AgNPs. In the soil exposure experiment, germination effects were less pronounced. The plant growth response differed by taxa with Lolium multiflorum growing more rapidly under both AgNO3 and GA-AgNP exposures and all other taxa having significantly reduced growth under GA-AgNP exposure. AgNO3 did not reduce the growth of any species while PVP-AgNPs significantly inhibited the growth of only one species. Our findings suggest important new avenues of research for understanding the fate and transport of NPs in natural media, the interactions between NPs and plants, and indirect and direct effects of NPs in mixed plant communities. PMID:23091638

  6. Retrospective dosimetry of Iodine-131 exposures using Iodine-129 and Caesium-137 inventories in soils--A critical evaluation of the consequences of the Chernobyl accident in parts of Northern Ukraine.

    PubMed

    Michel, R; Daraoui, A; Gorny, M; Jakob, D; Sachse, R; Romantschuk, L D; Alfimov, V; Synal, H-A

    2015-12-01

    The radiation exposure of thyroid glands due to (131)I as a consequence of the Chernobyl accident was investigated retrospectively based on (129)I and (137)Cs inventories in soils in Northern Ukraine. To this end, soil samples from 60 settlements were investigated for (129)I, (127)I, and (137)Cs by AMS, ICP-MS and gamma-spectrometry, respectively. Sampling was performed between 2004 und 2007. In those parts of Northern Ukraine investigated here the (129)I and (137)Cs inventories are well correlated, the variability of the individual (129)I/(137)Cs ratios being, however, high. Both the (129)I and (137)Cs inventories in the individual 5 samples for each settlement allowed estimating the uncertainties of the inventories due to the variability of the radionuclide deposition and consequently of the retrospective dosimetry. Thyroid equivalent doses were calculated from the (129)I and the (137)Cs inventories using aggregated dose coefficients for 5-year old and 10-year-old children as well as for adults. The highest thyroid equivalent doses (calculated from (129)I inventories) were calculated for Wladimirowka with 30 Gy for 5-years-old children and 7 Gy for adults. In 35 settlements of contamination zone II the geometric mean of the thyroid equivalent doses was 2.0 Gy for 5-years-old children with a geometric standard deviation (GSD) of 3.0. For adults the geometric mean was 0.47 Gy also with a GSD of 3.0. In more than 25 settlements of contamination zone III the geometric means were 0.82 Gy for 5-years old children with a GSD of 1.8 and 0.21 Gy for adults (GSD 1.8). For 45 settlements, the results of the retrospective dosimetry could be compared with thyroid equivalent doses calculated using time-integrated (131)I activities of thyroids which were measured in 1986. Thus, a critical evaluation of the results was possible which demonstrated the general feasibility of the method, but also the associated uncertainties and limitations. PMID:26254721

  7. Plasma magmavication of soils by nontransferred arc

    SciTech Connect

    Mayne, P.W.; Burns, S.E.; Circeo, L.J.

    2000-05-01

    Electrical plasma arcs create very high temperatures (T > 4,000 C) that can be specifically directed for the in-place melting of soils. This overview presents a summary of the basic features and capabilities of plasma torches having a nontransferred type of arc for the in situ vitrification of soils. Laboratory chamber experiments using 100 kW and 240 kW plasma systems and full-scale field trials using a 1 MW portable system have successfully melted a variety of soil types, including sands, silts, and clays. Within five minutes' exposure to the arc, a core region of magma forms within the soil matrix that expands radially outward and upward as the torch is pulled out vertically. Several days afterwards, the molten zone cools to form an artificial igneous rock similar to obsidian, basalt, or granite. The size of the vitrified mass is proportional to the electrical power demand. The plasma torch has a configuration similar to a flamethrower and will therefore be amenable to placement down boreholes for purposes of in situ ground modification and subsurface remediation.

  8. Determination of the potential for release of mercury from combustion product amended soils: Part 2 - Coal fly ash generated stabilized soil and degradation products

    SciTech Connect

    Mae Sexauer Gustin; Mei Xin; Jody Ericksen; George C. Fernandez

    2008-11-15

    The potential for mercury (Hg) releases to the air and water from three soils, two subbituminous coal fly ashes, and mixtures of these materials as stabilized soil was assessed. In addition, the potential for Hg release from crushed stabilized material mixed into soil simulating degradation over time was investigated. In general, atmospheric Hg deposition was measured for the ash and materials made using the ash with the higher Hg concentration, whereas the second ash material and materials generated using this ash exhibited emission as the dominant flux. Fluxes measured from stabilized material were less than that measured for the pure ash material but of the same direction. Although the stabilized and degraded stabilized materials exhibited Hg fluxes that were significantly different from base soils, values were within the range reported for low Hg-containing background soils. Because of limitations of the experimental design (i.e., reduced light exposures and measurement of flux from dry materials) reported fluxes are most likely underestimates of that which would occur in the natural environment. Materials made to simulate degradation of the stabilized material did not exhibit higher releases than the stabilized material alone. Synthetic Precipitation Leaching Procedure (SPLP; EPA method 1312) results showed that the chemistry of a soil, especially pH, may influence the amount of Hg released to soil solutions, with more acidic soils potentially enhancing Hg release. 25 refs., 9 figs., 4 tabs.

  9. Determination of the potential for release of mercury from combustion product amended soils: part 2--coal fly ash generated stabilized soil and degradation products.

    PubMed

    Gustin, Mae Sexauer; Xin, Mei; Ericksen, Jody; Fernandez, George C

    2008-11-01

    The potential for mercury (Hg) releases to the air and water from three soils, two subbituminous coal fly ashes, and mixtures of these materials as stabilized soil was assessed. In addition, the potential for Hg release from crushed stabilized material mixed into soil simulating degradation over time was investigated. In general, atmospheric Hg deposition was measured for the ash and materials made using the ash with the higher Hg concentration (ash 1, 0.25 microg x g(-1)), whereas the second ash material (ash 2; approximately 0.08 microg x g(-1)) and materials generated using this ash exhibited emission as the dominant flux. Fluxes measured from stabilized material were less than that measured for the pure ash material but of the same direction. Although the stabilized and degraded stabilized materials exhibited Hg fluxes that were significantly different from base soils, values were within the range reported for low Hg-containing background soils. Because of limitations of the experimental design (i.e., reduced light exposures and measurement of flux from dry materials) reported fluxes are most likely underestimates of that which would occur in the natural environment. Materials made to simulate degradation of the stabilized material did not exhibit higher releases than the stabilized material alone. Synthetic Precipitation Leaching Procedure (SPLP; EPA method 1312) results showed that the chemistry of a soil, especially pH, may influence the amount of Hg released to soil solutions, with more acidic soils potentially enhancing Hg release. PMID:19044165

  10. Soil water and vegetation management for cleanup of selenium contaminated soils

    SciTech Connect

    Not Available

    1989-05-01

    Over the past year scientists have initiatived a new effort aimed at developing a soil water and vegetation management plan for Kesterson Reservoir. The plan is intended to result in a gradual depletion of the inventory of soluble selenium at the Reservoir through a combination agriculturally oriented practices that enhance dissipation of selenium from near surface soils. Agriculturally oriented processes that will contribute to depletion include microbial volatilization from the soils, direct volatilization by living plants, decomposition and volatilization of selenium-bearing vegetation, harvest and removal of seleniferous vegetation, and leaching. The benefits of using this integrated approach are that (1) no single mechanism needs to be relied upon to detoxify the soils, (2) a stable plant community can be established during this period so that impacts to wildlife can be more easily evaluated and controlled, (3) cleanup and management of the site can be carried out in a cost-effective manner. The management plan is also intended to facilitate control over wildlife exposure to selenium contaminated biota by creating a well managed environment. The majority of research associated with this new effort is being carried out at a 200 m by 50 m test plot in Pond 7. A two-line irrigation system , providing local groundwater as an irrigation supply, has been installed. Through an intensive program of soil water sampling, soil gas sampling, vegetation sampling, groundwater monitoring, and soil moisture monitoring, the mass balance for selenium under irrigated conditions is being evaluated. These studies, in conjunction with supplementary laboratory experiments will provide the information needed to develop an optimal management plan for the site. 23 refs., 38 figs., 10 tabs.

  11. Mass Transport within Soils

    SciTech Connect

    McKone, Thomas E.

    2009-03-01

    Contaminants in soil can impact human health and the environment through a complex web of interactions. Soils exist where the atmosphere, hydrosphere, geosphere, and biosphere converge. Soil is the thin outer zone of the earth's crust that supports rooted plants and is the product of climate and living organisms acting on rock. A true soil is a mixture of air, water, mineral, and organic components. The relative proportions of these components determine the value of the soil for agricultural and for other human uses. These proportions also determine, to a large extent, how a substance added to soil is transported and/or transformed within the soil (Spositio, 2004). In mass-balance models, soil compartments play a major role, functioning both as reservoirs and as the principal media for transport among air, vegetation, surface water, deeper soil, and ground water (Mackay, 2001). Quantifying the mass transport of chemicals within soil and between soil and atmosphere is important for understanding the role soil plays in controlling fate, transport, and exposure to multimedia pollutants. Soils are characteristically heterogeneous. A trench dug into soil typically reveals several horizontal layers having different colors and textures. As illustrated in Figure 1, these multiple layers are often divided into three major horizons: (1) the A horizon, which encompasses the root zone and contains a high concentration of organic matter; (2) the B horizon, which is unsaturated, lies below the roots of most plants, and contains a much lower organic carbon content; and (3) the C horizon, which is the unsaturated zone of weathered parent rock consisting of bedrock, alluvial material, glacial material, and/or soil of an earlier geological period. Below these three horizons lies the saturated zone - a zone that encompasses the area below ground surface in which all interconnected openings within the geologic media are completely filled with water. Similarly to the unsaturated zone

  12. Nitrogen loss from high N-input vegetable fields: a) Direct N2O emissions b) Spatiotemporal variability of N species (N2O, NH4+, NO3-) in soils

    NASA Astrophysics Data System (ADS)

    Palmer, I.; Pfab, H.; Ruser, R.; Fiedler, S.

    2009-04-01

    filled pore space was calculated. In total 10 different treatments were tested with 4 replicates each. We hypothesized that: (1) Distinct N-species, their portion and level, vary across a spatial and temporal scale dependent from N-input amount and modification of fertilizer. (2) High N-input is accompanied by enhanced microbial activity which results higher N2O concentration in soils. (3) Disturbance due to management (fertilization, plant residues) leads to short-term accu-mulation in N2O concentrations. We found a fast response of all measured N-species after fertilization as well as after application of harvest residues in all treatments. Ammonium and nitrate increased immediately in 0-25 cm after N-input in all treatments, whereas with increasing soil depth the response is delayed. The highest fertilizer level results in the highest amounts of ammonium and nitrate. Nitrogen fer-tilization led to distinctively higher N2O concentration in air filled pores compared to the non-fertilized soil (control), in all three depths in all fertilizer variations. In general, highest level of fertilizer was accompanied by highest concentrations of nitrous oxide in the gaseous soil phase in all depths investigated. This effect is significant and most clearly in 0-25 cm. In 25-50 cm and 50-75 cm, other parameters seem to play a more important role. The most significant differences between fertilizer types occur in 0-25 cm as well. Plots fertilized with ENTEC® show significantly higher N2O concentrations than the control plots, but are sig-nificantly lower than an ASN or depot fertilization of the same level. These results are in good accordance with the direct N2O-emissions measured in the same plots. A small time lag was observed in the N2O concentration in soil air in comparison to the above-ground emissions after system disturbance like fertilization or harvest. It can be concluded that high N-input as typical for vegetable production (both as fertilizer or easily mineralizable

  13. Assessing soil quality in organic agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil quality is directly linked to food production, food security, and environmental quality (i.e. water quality, global warming, and energy use in food production). Unfortunately, moderate to severe degeneration of soils (i.e., loss of soil biodiversity, poor soil tilth, and unbalanced elemental c...

  14. Reducing human exposure to Mycobacterium avium.

    PubMed

    Falkinham, Joseph O

    2013-08-01

    In light of the increasing prevalence of Mycobacterium avium pulmonary disease and the challenges of treating patients with M. avium infection, consideration of measures to reduce exposure is warranted. Because M. avium inhabits water and soil, humans are surrounded by that opportunistic pathogen. Because infection has been linked to the presence of M. avium in household plumbing, increasing hot water temperature, reducing aerosol (mist) exposures in bathrooms and showers, and installing filters that prevent the passage of mycobacteria will likely reduce M. avium exposure. Granular activated carbon (charcoal) filters support the growth of M. avium and should be avoided. When gardening, avoid the inhalation of soil dusts by using a mask or wetting the soil because peat-rich potting soils have high numbers of mycobacteria. PMID:23952861

  15. Effect of simulated acid rain on nitrification and nitrogen mineralization in forest soils

    SciTech Connect

    Strayer, R.F.; Lin, C.J.; Alexander, M.

    1981-10-01

    To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm/hour or an intermittent 1.5-hour application of 1.2 cm of simulated acid rain twice weekly for 19 weeks. The upper 1.0- to 1.5-cm portions of soil from treated columns were used to determine the changes in inorganic N levels in the soil. Nitrification of added ammonium (NH/sub 4//sup +/) was inhibited following continuous exposure of soil to simulated acid rain of pH 4.1-3.2. The extent of the inhibition was directly related to the acidity of the simulated rain solutions. The production of inorganic N in the absence of added NH/sub 4//sup +/ was either stimulated or unaffected following continuous treatment of soils with pH 3.2 simulated acid rain. The addition of nitrapyrin (2-chloro-6-(trichloromethyl)pyridine), an inhibitor of autotrophic nitrification, caused a decrease in nitrification in water-treated soil but had little effect on nitrification in soil treated with pH 3.2 simulated acid rain. Intermittent applications of simulated acid rain (pH 3.5-4.1) for 19 weeks partially inhibited nitrate (NO/sub 3//sup -/) production in soil amended with NH/sub 4//sup +/ following the exposure period, but NO/sub 3//sup -/ production in unamended soil was either unaffected or stimulated.

  16. The relative importance of hydrophobicity in determining runoff-infiltration processes in burned forest soils

    NASA Astrophysics Data System (ADS)

    Wittenberg, Lea; Malkinson, Dan; Voogt, Annelies; Leska, Danny; Argaman, Eli; Keesstra, Saskia

    2010-05-01

    Wildfires induce fundamental changes to vegetation and soil structure/texture which conseqeuntly have major impacts on infiltration capacity, overland flow generation, runoff and sediment yields. The relative importance, however, of fire-induced soil water repellency (WR) on hydrological and erosional processes is somewhat controversial, partially, as the direct effects of soil WR in-situ field conditions have been difficult to isolate. It is generally accepted that hydrophobicity is caused by the formation of organic substances in forest soils, while burning is considered to enhance this process. Given the complex response of the soil-vegetation system to burning, soil WR is only one of several affecting soil hydrology. Other factors include the physical sealing of soils triggered by rain drops energy, the increase in soil erodibility due to changes in soil aggregates, and the role of the ash in sealing the burned surface. The degree and spatial distribution of WR burned varies considerably with fire severity, soil and vegetation type, soil moisture content and time since burning. Nevertheless, given the inverse relationship between soil moisture and hydrophobicity, the role of the latter in determining overland flow during wet winters when the soil is mostly inundated, is marginal. Following a 60 ha wildfire, which took place at the Pe'eram catchment during July 2009, we assessed the spatio-temporal distribution of WR in a burned Pinus halepensis forest. The site, located in the Upper Galille, Israel, was severely burned; the combustion removed all understory vegetation and burned down some of the trunks, leaving a thick layer of ash. The soils composed of reddish-brown clay loam forest soil and terra rossa on limestone bedrock, greyish light rendzina characterises the marl and chalk exposures. To consider the effect of distance from trees, in-situ hydrophobicity was assessed within a week, month and five months after the fire, using the WDPT test. Measurements

  17. Soil Evaporation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...

  18. Mouse Assay for Determination of Arsenic Bioavailability in Contaminated Soils

    EPA Science Inventory

    Background: Accurate assessment of human exposure estimates from arsenic-contaminated soils depends upon estimating arsenic (As) soil bioavailability. Development of bioavailability assays provides data needed for human health risk assessments and supports development and valida...

  19. Behavioral response and kinetics of terrestrial atrazine exposure in American toads (bufo americanus)

    USGS Publications Warehouse

    Storrs, Mendez S.I.; Tillitt, D.E.; Rittenhouse, T.A.G.; Semlitsch, R.D.

    2009-01-01

    Amphibians in terrestrial environments obtain water through a highly vascularized pelvic patch of skin. Chemicals can also be exchanged across this patch. Atrazine (ATZ), a widespread herbicide, continues to be a concern among amphibian ecologists based on potential exposure and toxicity. Few studies have examined its impact on the terrestrial juvenile or adult stages of toads. In the current study, we asked the following questions: (1) Will juvenile American toads (Bufo americanus) avoid soils contaminated with ATZ? (2) Can they absorb ATZ across the pelvic patch? (3) If so, how is it distributed among the organs and eventually eliminated? We conducted a behavioral choice test between control soil and soil dosed with ecologically relevant concentrations of ATZ. In addition, we examined the uptake, distribution, and elimination of water dosed with 14C-labeled ATZ. Our data demonstrate that toads do not avoid ATZ-laden soils. ATZ crossed the pelvic patch rapidly and reached an apparent equilibrium within 5 h. The majority of the radiolabeled ATZ ended up in the intestines, whereas the greatest concentrations were observed in the gall bladder. Thus, exposure of adult life stages of amphibians through direct uptake of ATZ from soils and runoff water should be considered in risk evaluations. ?? 2009 Springer Science+Business Media, LLC.

  20. Adaptation of soil microbial activity will accelerate the climate change induced release of C from the world's soils

    NASA Astrophysics Data System (ADS)

    Karhu, K.; Auffret, M.; Dungait, J.; Fraser, F.; Hopkins, D.; Prosser, J.; Singh, B.; Subke, J.; Wookey, P.; Ågren, G.; Hartley, I. P.

    2013-12-01

    There are concerns that global warming may stimulate decomposition rates in soils, with the extra CO2 released representing a positive feedback to climate change. However, there is growing recognition that adaptation of soil microbial communities to temperature changes may alter the potential rate of carbon release. Critically, recent studies have produced conflicting results in terms of whether the medium-term soil microbial community response to temperature reduces (thermal acclimation) or enhances (enhancement) the instantaneous direct effects of temperature on decomposition rates. This lack of understanding adds considerably to uncertainty in predictions of the magnitude and direction of carbon-cycle feedbacks to climate change. Here we present results from one of the most extensive investigations ever undertaken into the role that acclimatory or enhancing responses play in controlling the temperature sensitivity of decomposition in soils collected from the Arctic to the Amazon, and representing a range of ecosystem types. Investigating the impacts of adaptation to temperature is currently only possible in controlled laboratory experiments, in which fluctuations in substrate availability can be minimized. In our novel approach, soils are incubated at 3°C above mean annual temperature (MAT), until respiration rates stabilize, then cooled by 6°C (MAT -3 °C) and the potential for respiration rates to recover during extended exposure to lower temperatures is determined. Our approach avoids the issues associated with substrate depletion in warming studies, but still tests whether adaptation enhances or reduces the direct impact of temperature on microbial activity. We also investigated the mechanisms underlying changes in microbial respiration by quantifying how microbial community structure, microbial biomass, mass-specific activity, carbon-use efficiency, and enzyme activities responded to our temperature treatments. Our results indicate that compensatory