Sample records for tclp toxicity characteristic
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Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali
2016-03-01
As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH < 6.0). Thus, Zn leaching is enhanced using the modified TCLP. While Pb leached readily during the first 126 h and then leachate concentrations decreased to below the analytical detection limit. To conclude, this modified TCLP is a more suitable method for these cement rotary kiln co-processing products.
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The goal of this document is to assist the regulated community to make proper utilization of the Toxicity Characteristic Leaching Procedure (TCLP) to demonstrate compliance with the Toxicity Characteristic (TC) and Land Ban Regulations.
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Investigations of metal leaching from mobile phone parts using TCLP and WET methods.
Yadav, Satyamanyu; Yadav, Sudesh
2014-11-01
Metal leaching from landfills containing end-of-life or otherwise discarded mobile phones poses a threat to the environment as well as public health. In the present study, the metal toxicity of printed wire boards (PWBs), plastics, liquid crystal displays (LCDs) and batteries of mobile phones was assessed using the Toxicity Characteristics Leaching Procedures (TCLP) and the Waste Extraction Test (WET). The PWBs failed TCLP for Pb and Se, and WET for Pb and Zn. In WET, the two PWB samples for Pb and Zn and the battery samples for Co and Cu failed the test. Furthermore, the PWBS for Ni and the battery samples for Ni and Co failed the WET in their TCLP leachates. Both, Ni and Co are the regulatory metals in only WET and not covered under TCLP. These observations indicate that the TCLP seems to be a more aggressive test than the WET for the metal leaching from the mobile phone parts. The compositional variations, nature of leaching solution (acetate in TCLP and citrate in WET) and the redox conditions in the leaching solution of the PWBs resulted in different order of metals with respect to their amounts of leaching from PWBs in TCLP (Fe > Pb > Zn > Ni > Co > Cu) and WET (Zn > Fe > Ni > Pb > Cu). The metal leaching also varied with the make, manufacturing year and part of the mobile phone tested. PWBs, plastics and batteries should be treated as hazardous waste. Metal leaching, particularly of Se and Pb, from mobile phones can be harmful to the environment and human health. Therefore, a scientifically sound and environmentally safe handling and disposal management system needs to be evolved for the mobile phone disposal. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Chen, Jian-Jun; Yu, Tian-Ming; Wang, Bi-Ling; Xie, Zheng-Miao
2010-01-01
A pot experiment was conducted to evaluate the effects of phosphate-containing (P) amendments on the toxicity and bioavailability of Pb and Zn in a soil contaminated by mining tailings using toxicity characteristic leaching procedure (TCLP) and water soluble, exchangeable leaching procedures in order to find out the appropriate P application rates to reduce the soil TCLP extractable Pb to below the USA EPA's regulatory limit levels. The results showed that TCLP extractable Pb concentrations were significantly decreased by up to 93.3% for MPP treatments and up to 68.5% for SSP treatments after P application. The dose required to reduce leachable Pb below the EPA's regulatory limit level was found to be around the molar ratio of v(P/Pb) = 0.6 for MPP and 1.8 for SSP. It was also found both MPP and SSP could reduce the exchangeable Pb and Zn concentrations that all bio-available Zn forms including water soluble, exchangeable, and TCLP extractable forms in soil were significantly and negatively correlated to soil pH values, indicating that the content of Zn in the soil was mostly controlled by soil pH value even after P application. These results suggest that P as MPP and SSP could successfully decrease the toxicity and bioavailability of Pb and Zn in the contaminated soil.
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Prolonged toxicity characteristic leaching procedure for nickel and copper aluminates.
Shih, Kaimin; Tang, Yuanyuan
2011-04-01
The toxicity characteristic leaching procedure (TCLP) is a regulatory testing method widely employed to evaluate the environmental friendliness of waste materials. TCLP analysis provides a fast, easy and economical way to determine the mobility of waste pollutants under simulated landfill conditions. Recent studies on metal stabilization have reported the potential for nickel and copper aluminates to form in thermal treatment conditions, and suggested a more reliable method of stabilizing hazardous metals, particularly when products are to be reused. There is thus an urgent need for a convenient and effective method of quantifying metal leachability and identifying the metal leaching behavior of sparingly soluble materials. In this study, standard TCLP analysis was modified into a prolonged leaching experiment to investigate the leaching behavior of nickel and copper oxides (NiO and CuO) and their aluminates (NiAl(2)O(4), CuAl(2)O(4) and CuAlO(2)). The results demonstrate the difficulty of differentiating the leachability of highly insoluble phases, such as NiO and NiAl(2)O(4), using the standard TCLP. The prolonged TCLP method, however, confirmed NiAl(2)O(4) to have a lower degree of intrinsic leachability than NiO and that it could be expected to undergo congruent dissolution under landfill conditions. For the more soluble copper system, the aluminates were still found to possess a much lower degree of leachability, and their leaching behavior to follow an incongruent dissolution pattern. The results of this study prove prolonged TCLP analysis to be a convenient and effective way to evaluate the environmental friendliness of metal waste and to identify the leaching behavior of waste materials.
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Baba, Alper; Kaya, Abidin
2004-11-01
Use of lignite in power generation has led to increasing environmental problems associated not only with gaseous emissions, but also with the disposal of ash residues. In particular, use of low quality coals with high ash content results in huge quantities of both fly and bottom ashes to be disposed of. A main problem related to coal ash disposal is the heavy metal content of the residue. In this regard, experimental results of numerous studies indicate that toxic trace metals may leach when fly and bottom ashes are in contact with water. In this study, fly and bottom ash samples obtained from thermal power plants, namely Yenikoy, Kemerkoy and Yatagan, located at the southwestern coast of Turkey, were subjected to toxicity tests such as the extraction (EP) and toxicity characteristic leaching (TCLP) procedures of the US Environmental Protection Agency (USEPA) and the so-called 'Method A' extraction procedure of the American Society of Testing and Material (ASTM). The geochemical composition of ash samples showed variations depending on the coal burned in the plants. Furthermore, the EP, TCLP and ASTM toxicity tests showed variations such that the ash samples were classified as 'toxic waste' based on EP and TCLP results whereas they were classified as 'non-toxic' based on ASTM results, indicating test results are pH dependent. When the extraction results were compared with the chemical composition of water samples obtained in the vicinity of the thermal power plants, it was found that the results obtained using the ASTM procedure cannot be used to predict subsurface contamination whereas the EP and TCLP procedures can be used.
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Kede, Maria Luiza F. M.; Correia, Fabio V.; Conceição, Paulo F.; Salles Junior, Sidney F.; Marques, Marcia; Moreira, Josino C.; Pérez, Daniel V.
2014-01-01
The objective of the present study was to investigate the reduction of mobility, availability and toxicity found in soil contaminated with lead (Pb) and cadmium (Cd) from Santo Amaro Municipality, Bahia, Brazil using two combined methods, commonly tested separately according to the literature: metal mobilization with phosphates and phytoextraction. The strategy applied was the treatment with two sources of phosphates (separately and mixed) followed by phytoremediation with vetiver grass (Vetiveria zizanioides (L.)). The treatments applied (in triplicates) were: T1—potassium dihydrogen phosphate (KH2PO4); T2—reactive natural phosphate fertilizer (NRP) and; T3—a mixture 1:1 of KH2PO4 and NRP. After this step, untreated and treated soils were planted with vetiver grass. The extraction procedures and assays applied to contaminated soil before and after the treatments included metal mobility test (TCLP); sequential extraction with BCR method; toxicity assays with Eisenia andrei. The soil-to-plant transfer factors (TF) for Pb and Cd were estimated in all cases. All treatments with phosphates followed by phytoremediation reduced the mobility and availability of Pb and Cd, being KH2PO4 (T1) plus phytoremediation the most effective one. Soil toxicity however, remained high after all treatments. PMID:25386955
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Lin, Shengxuan; Zhou, Xuedong; Ge, Liya; Ng, Sum Huan; Zhou, Xiaodong; Chang, Victor Wei-Chung
2016-10-01
Heavy metals and some metalloids are the most significant inorganic contaminants specified in toxicity characteristic leaching procedure (TCLP) in determining the safety of landfills or further utilization. As a consequence, a great deal of efforts had been made on the development of miniaturized analytical devices, such as Microchip Electrophoresis (ME) and μTAS for on-site testing of heavy metals and metalloids to prevent spreading of those pollutants or decrease the reutilization period of waste materials such as incineration bottom ash. However, the bottleneck lied in the long and tedious conventional TCLP that requires 18 h of leaching. Without accelerating the TCLP process, the on-site testing of the waste material leachates was impossible. In this study, therefore, a new accelerated leaching method (ALM) combining ultrasonic assisted leaching with tumbling was developed to reduce the total leaching time from 18 h to 30 min. After leaching, the concentrations of heavy metals and metalloids were determined with ICP-MS or ICP-optical emission spectroscopy. No statistical significance between ALM and TCLP was observed for most heavy metals (i.e., cobalt, manganese, mercury, molybdenum, nickel, silver, strontium, and tin) and metalloids (i.e., arsenic and selenium). For the heavy metals with statistical significance, correlation factors derived between ALM and TCLP were 0.56, 0.20, 0.037, and 0.019 for barium, cadmium, chromium, and lead, respectively. Combined with appropriate analytical techniques (e.g., ME), the ALM can be applied to rapidly prepare the incineration bottom ash samples as well as other environmental samples for on-site determination of heavy metals and metalloids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Leaching characteristics of fly ash from thermal power plants of Soma and Tuncbilek, Turkey.
Baba, Alper; Kaya, Abidin
2004-02-01
Use of lignite in power generation has led to increasing environmental problems associated not only with gaseous emissions but also with the disposal of ash residues. In particular, use of low quality coal with high ash content results in huge quantities of fly ash to be disposed of. The main problem related to fly ash disposal is the heavy metal content of the residue. In this regard, experimental results of numerous studies indicate that toxic trace metals may leach when fly ash contacts water. In this study, fly ash samples obtained from thermal power plants, namely Soma and Tunçbilek, located at the west part of Turkey, were subjected to toxicity tests such as European Committee for standardization (CEN) and toxicity characteristic leaching (TCLP) procedures of the U.S. Environmental Protection Agency (U.S. EPA). The geochemical composition of the tested ash samples from the power plant show variations depending on the coal burned in the plants. Furthermore, the CEN and TCLP extraction results showed variations such that the ash samples were classified as 'toxic waste' based on TCLP result whereas they were classified as 'non-toxic' wastes based on CEN results, indicating test results are pH dependent.
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Using enzyme bioassays as a rapid screen for metal toxicity
Choate, LaDonna M.; Ross, P.E.; Blumenstein, E. P.; Ranville, James F.
2005-01-01
Mine tailings piles and abandoned mine soils are often contaminated by a suite of toxic metals, which were released in the mining process. Traditionally, toxicity of such areas has been determined by numerous chemical methods including the Toxicity Characteristic Leachate Procedure (TCLP) and traditional toxicity tests using organisms such as the cladoceran Ceriodaphnia dubia. Such tests can be expensive and time-consuming. Enzymatic bioassays may provide an easier, less costly, and more time-effective toxicity screening procedure for mine tailings and abandoned mine soil leachates. This study evaluated the commercially available MetPLATE™ enzymatic toxicity assay test kit. The MetPLATE™ assay uses a modified strain of Escherichia coli bacteria as the test organism. Toxicity is defined by the activity of β-galactosidase enzyme which is monitored colorometrically with a 96-well spectrophotometer. The study used water samples collected from North Fork Clear Creek, a mining influenced water (MIW) located in Colorado. A great benefit to using the MetPLATE™ assay over the TCLP is that it shows actual toxicity of a sample by taking into account the bioavailability of the toxicants rather than simply measuring the metal concentration present. Benefits of the MetPLATE™ assay over the use of C. dubia include greatly reduced time for the testing process (∼2 hours), a more continuous variable due to a greater number of organisms present in each sample (100,000+), and the elimination of need to maintain a culture of organisms at all times.
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Heavy metal speciation and toxicity characteristics of tannery sludge
NASA Astrophysics Data System (ADS)
Juel, Md. Ariful Islam; Chowdhury, Zia Uddin Md.; Ahmed, Tanvir
2016-07-01
Heavy metals present in tannery sludge can get mobilized in the environment in various forms and can be a cause for concern for the natural ecosystem and human health. The speciation of metals in sludge provides valuable information regarding their toxicity in the environment and determines their suitability for land application or disposal in landfills. Concentrations of seven heavy metals (Cr, Pb, Cd, Ni, Zn, As and Cu) in tannery sludge were determined to evaluate their toxicity levels. Metal contents ranged over the following intervals: As: 1.52-2.07 mg/kg; Pb: 57.5-67 mg/kg; Cr: 15339-26501 mg/kg; Cu: 261.3-579.5 mg/kg; Zn: 210.2-329.1 mg/kg and Ni: 137.5-141.3 mg/kg (dry weight basis). The concentrations of all heavy metals in the sludge samples were lower compared to EPA guidelines except chromium which was found to be several orders of magnitude higher than the guideline value. Toxicity Characteristics Leaching Procedure (TCLP) test indicated that the leaching potential of chromium was higher compared to the other heavy metals and exceeded the EPA land disposal restriction limits. To quantitatively assess the environmental burden of the chromium associated with tannery sludge, the IMPACT 2002+ methodology was adopted under the SimaPro software environment. Considering the USEPA limit for chromium as the baseline scenario, it was found that chromium in the tannery sludge had 6.41 times higher impact than the baseline in the categories of aquatic ecotoxicity, terrestrial ecotoxicity and non-carcinogens. Chromium has the highest contribution to toxicity in the category of aquatic ecotoxicity while copper is the major contributor to the category of terrestrial ecotoxicity in the tannery sludge.
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Unda-Calvo, Jessica; Martínez-Santos, Miren; Ruiz-Romera, Estilita
2017-04-01
In the present study, the physiologically based extraction test PBET (gastric and intestinal phases) and two chemical based extraction methods, the toxicity characteristic leaching procedure (TCLP) and the sequential extraction procedure BCR 701 (Community Bureau of Reference of the European Commission) have been used to estimate and evaluate the bioaccessibility of metals (Fe, Mn, Zn, Cu, Ni, Cr and Pb) in sediments from the Deba River urban catchment. The statistical analysis of data and comparison among physiological and chemical methods have highlighted the relevance of simulate the gastrointestinal tract environment since metal bioaccessibility seems to depend on water and sediment properties such as pH, redox potential and organic matter content, and, primordially, on the form in which metals are present in the sediment. Indeed, metals distributed among all fractions (Mn, Ni, Zn) were the most bioaccessible, followed by those predominantly bound to oxidizable fraction (Cu, Cr and Pb), especially near major urban areas. Finally, a toxicological risk assessment was also performed by determining the hazard quotient (HQ), which demonstrated that, although sediments from mid- and downstream sampling points presented the highest metal bioaccessibilities, were not enough to have adverse effects on human health, Cr being the most potentially toxic element. Copyright © 2017 Elsevier Inc. All rights reserved.
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Leaching and toxicity behavior of coal-biomass waste cocombustion ashes.
Skodras, G; Prokopidou, M; Sakellaropoulos, G P
2006-08-01
Land disposal of ash residues, obtained from the cocombustion of Greek lignite with biomass wastes, is known to create problems due to the harmful constituents present. In this regard, the leachability of trace elements from lignite, biomass, and blends cocombustion ashes was investigated by using the Toxicity Characteristic Leaching Procedure (TCLP) of the US Environmental Protection Agency (US EPA). In this work, the toxicity of the aqueous leachates and the concentrations of the metals obtained from the leaching procedure were measured using the Microtox test (Vibrio fischeri) and inductive coupled plasma-atomic emission spectrometer (ICP-AES), respectively. The toxic effects of most leachates on Vibrio fischeri were found to be significantly low in both 45% and 82% screening test protocols. However, the liquid sample originating from olive kernels fly ash (FA4) caused the highest toxic effect in both protocols, which can be attributed to its relatively high concentrations of As, Cd, Co, Cu, Mn, Ni, and Zn. Copyright 2006 Wiley Periodicals, Inc.
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Chiang, Kung-Yuh; Tsai, Chen-Chiu; Wang, Kuen-Sheng
2009-01-01
This study investigates four extraction methods (water extraction, toxicity characteristics leaching procedure (TCLP), modified TCLP with pH control, and sequential chemical extraction (SCE)), each representing different liquid-to-solid (L/S) ratios, pH controls, and types of leachant, and their effects on the leaching concentration of heavy metals in municipal solid waste (MSW) incinerator air pollution control (APC) residue. The results indicated that for extraction with distilled water, the heavy metal leaching concentration (mg/l) decreased with L/S ratio, but the amount of heavy metal released (AHMR), defined as the leached amount of heavy metals to the weight of the tested sample (mg/kg), increased with an increase in L/S ratio, in the range of 2-100. The results also showed that both the leaching concentration and the amount of released metals were strongly pH-dependent in the TCLP and modified TCLP tests. In the case of pHs lower than 6.5, the leaching concentrations of Cd, Pb, Cu, Zn, and Cr decreased with an increase in pH. As pH increased higher than 6.5, Cr and Zn were almost insoluble. Meanwhile, Cd and Cu also showed a similar trend but at pHs of 8.5 and 7.5, respectively. Due to the nature of amphoteric elements, in the case of pHs higher than 7, the Pb leaching concentration increased with increasing pH. In modified TCLP tests with the pH value controlled at the same level as in the SCE test, the heavy metal speciation approached the extractable carbonate bound fraction by the SCE. Both amounts of targeted metals leached from the SCE and modified TCLP tests were much higher than those for the regular TCLP and water extraction tests.
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Leaching assessments of toxic metals in waste plasma display panel glass.
Chen, Mengjun; Jiang, Pengfei; Chen, Haiyan; Ogunseitan, Oladele A; Li, Yungui
2015-06-01
The plasma display panel (PDP) is rapidly becoming obsolete, contributing in large amounts to the electronic waste stream. In order to assess the potential for environmental pollution due to hazardous metals leached from PDP glass, standardized leaching procedures, chemical speciation assessments, and bioavailability tests were conducted. According to the Toxicity Characteristic Leaching Procedure (TCLP), arsenic in back glass was present at 4.46 ± 0.22 mg/L, close to its regulation limit of 5 mg/L. Zn is not available in the TCLP, but its TCLP leaching concentration in back glass is 102.96 ± 5.34 mg/L. This is because more than 90% of Zn is in the soluble and exchangeable and carbonate fraction. We did not detect significant levels of Ag, Ba, or Cu in the TCLP leachate, and the main fraction of Ag and Ba is residual, more than 95%, while the fraction distribution of Cu changes SEP by SEP. Ethylenediamine tetraacetic acid (EDTA)- and diethylenetriamine pentaacetic acid (DTPA)-extractable Ag, As, Ba, Cu, Zn, and Ni indicate a lower biohazards potential. These results show that, according to the EPA regulations, PDP glass may not be classified as hazardous waste because none of the metals exceeded their thresholds in PDP leachate. However, the concentrations of As and Zn should be lowered in the manufacturing process and finished product to avoid potential pollution problems. The plasma display panel is rapidly becoming obsolete because of the liquid crystal display. In this study, the leachability of heavy metals contained in the waste plasma display panel glass was first examined by standardized leaching tests, typical chemical speciation assessments, and bioavailability tests, providing fundamental data for waste PDP glass recovery, recycling, and reuse.
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Leaching characteristics of copper flotation waste before and after vitrification.
Coruh, Semra; Ergun, Osman Nuri
2006-12-01
Copper flotation waste from copper production using a pyrometallurgical process contains toxic metals such as Cu, Zn, Co and Pb. Because of the presence of trace amounts of these highly toxic metals, copper flotation waste contributes to environmental pollution. In this study, the leaching characteristics of copper flotation waste from the Black Sea Copper Works in Samsun, Turkey have been investigated before and after vitrification. Samples obtained from the factory were subjected to toxicity tests such as the extraction procedure toxicity test (EP Tox), the toxicity characteristic leaching procedure (TCLP) and the "method A" extraction procedure of the American Society of Testing and Materials. The leaching tests showed that the content of some elements in the waste before vitrification exceed the regulatory limits and cannot be disposed of in the present form. Therefore, a stabilization or inertization treatment is necessary prior to disposal. Vitrification was found to stabilize heavy metals in the copper flotation waste successfully and leaching of these metals was largely reduced. Therefore, vitrification can be an acceptable method for disposal of copper flotation waste.
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PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD
Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...
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Jang, Yong-Chul; Townsend, Timothy G
2003-10-15
The proper management of discarded electronic devices (E-waste) is an important issue for solid waste professionals because of the magnitude of the waste stream and because these devices often contain a variety of toxic metals (e.g., lead). While recycling of E-waste is developing, much of this waste stream is disposed in landfills. Leaching tests are frequently used to characterize the potential of a solid waste to leach when disposed in a landfill. In the United States, the Toxicity Characteristic Leaching Procedure (TCLP) is used to determine whether a solid waste is a hazardous waste by the toxicity characteristic. The TCLP is designed to simulate worse-case leaching in a landfill environment where the waste is co-disposed with municipal solid waste (MSW). While the TCLP is a required analysis from a regulatory perspective, the leachate concentrations measured may not accurately reflect the concentrations observed under typical landfill conditions. Another method that can be performed to assess the degree a pollutant might leach from a waste in a landfill is to use actual landfill leachate as the leaching solution. In this study, two lead-containing components found in electronic devices (printed wire boards from computers and cathode ray tubes from computers and televisions) were leached using the TCLP and leachates from 11 Florida landfills. California's Waste Extraction Test (WET) and the Synthetic Precipitation Leaching Procedure were also performed. The results indicated that the extractions using MSW landfill leachates resulted in lower lead concentrations than those by the TCLP. The pH of the leaching solution and the ability of the organic acids in the TCLP and WET to complex with the lead are factors that regulate the amount of lead leached.
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Treatment of RDX and/or HMX Using Mulch Biowalls
2008-04-01
industrial classification TAL target analyte list TCE trichloroethene TCLP toxicity characteristic leachate procedure TNB 1,3,5-Trinitobenzene TNT... leachate procedure (TCLP) testing results for the mulch fill in the site-specific treatability phase confirmed no leaching of the target...0.01% 1 ɘ.001% 0.1% * i. Presence of other remediation technologies in the immediate vicinity No 4 No Yes, active phytoremediation in Pink Water
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40 CFR 261.24 - Toxicity characteristic.
Code of Federal Regulations, 2010 CFR
2010-07-01
... the contaminants listed in table 1 at the concentration equal to or greater than the respective value... Hazardous Waste Number specified in Table 1 which corresponds to the toxic contaminant causing it to be hazardous. Table 1—Maximum Concentration of Contaminants for the Toxicity Characteristic EPA HW No. 1...
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Assessment of Pb, Cd, Cr and Ag leaching from electronics waste using four extraction methods.
Keith, Ashley; Keesling, Kara; Fitzwater, Kendra K; Pichtel, John; Houy, Denise
2008-12-01
Heavy metals present in electronic components may leach upon disposal and therefore pose significant environmental hazards. The potential leaching of Pb, Cd, Cr and Ag from PC cathode ray tubes, printed circuit boards (PCBs), PC mice, TV remote controls, and mobile phones was assessed. After controlled crushing, each component was extracted using the Toxicity Characteristic Leaching Procedure (TCLP), EPA Method 1312 (SPLP), NEN 7371 (Dutch Environmental Agency), and DIN S4 (Germany). The TCLP consistently leached the greatest amounts of Pb from all components. The SPLP, NEN 7371 and DIN S4 extracted relatively small amounts of metals compared with the TCLP and were not considered effective as leaching tests for e-waste. The smallest size fraction (< 2 mm) of CRT glass and PCBs leached significantly (p < 0.05) highest Pb via the TCLP. A modified TCLP removed 50.9% more extractable Pb compared with the conventional procedure.
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Frequent Questions about the Delisting Risk Assessment Software (DRAS)
Frequent technical questions such Surface Impoundment Requires Corrections, How Do I Assess Toxicity Characteristic Leaching Procedure (TCLP) or Leachability in a Liquid Waste Sample?, Aggregate Hazard Index and Cancer Risk Output Table Correction.
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Assessing Metal Mobilization from Industrially Lead-Contaminated Soils Located at an Urban Site
A series of leaching and partitioning tests (Toxicity Characteristic Leaching Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP), Controlled Acidity Leaching Protocol (CALP), Acid Neutralization Capacity (ANC), and sequential extraction) were applied to three dif...
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Biological Treatment of Solvent-Based Paint
2011-01-01
ESTCP Environmental Security Technology Certification Program FK-WTP Fort Kamehameha Wastewater Treatment Plant FTIR Fourier Transform Infrared...established by the Fort Kamehameha Wastewater Treatment Plant (FK-WTP) for the water; toxicity characteristic leaching procedure (TCLP) requirements for
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[Environmental toxicity of waste foundry sand].
Zhang, Hai-Feng; Wang, Yu-Jue; Wang, Jin-Lin; Huang, Tian-You; Xiong, Ying
2013-03-01
The metal leaching characteristics and volatile organic compounds (VOCs) of five different types of waste foundry sands were analyzed with the toxicity characteristic leaching procedure (TCLP) and head space-gas chromatography (HS-GC). Microtox and soil dehydrogenase activity (DHA) tests were then used to evaluate the bio-effects of these waste sands. The results showed that due to the different metals poured and casting materials used to make the sand molds, there was significant difference among the five waste foundry sands in the compositions and concentrations of metal and organic pollutants. The concentrations of Fe in the leachates of iron and steel casting waste foundry sand exceeded the maximal allowable concentrations specified in the National Standard of Drinking Water Quality, whereas the As concentration in the leachate of aluminum casting waste foundry sand exceeded the standard. The five waste foundry sands had quite different compositions and levels of VOCs, which resulted in different levels of inhibition effects on the luminescent bacteria (30% and 95%). Additionally, the soil DHA tests suggested that metal pollutants in waste foundry sands may inhibit the soil microbial activity, whereas organics in the sands may slightly promote the microbial activity. The results of this study indicated that the waste foundry sands may pose considerable threat to the environment when improperly disposed.
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Chen, Yu; Chen, Mengjun; Li, Yungui; Wang, Bin; Chen, Shu; Xu, Zhonghui
2018-05-08
Technology innovation has accelerated progress in Information and Communications Technology (ICT), especially in the mobile phones sector. Concurrently, local, national, and international governments are enforcing stricter regulations to protect natural resources and human health. The paper attempts to address the question: Have technological innovations and regulation development had a positive impact on ecosystems and public health? We identified 36 waste mobile phones (WMPs) manufactured between 2002 and 2013, assessed their metals concentration, leachability, and potential impact on environment and human health using digestion, Toxicity Characteristic Leaching Procedure (TCLP), and USEtox model, respectively. The results highlight that regulations did not have significant impact on total metal content, except some heavy metals, while technology innovation recorded stronger impact. WMPs should be classified as hazardous due to excessive lead content. Copper posed the most significant ecotoxicity risk, and chromium showed the most significant risk for both cancerous and non-cancerous diseases. Additionally, we demonstrated that WMPs toxicity increased with technology innovation.
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Leachability of Arsenic and Heavy Metals from Mine Tailings of Abandoned Metal Mines
Lim, Mihee; Han, Gi-Chun; Ahn, Ji-Whan; You, Kwang-Suk; Kim, Hyung-Seok
2009-01-01
Mine tailings from an abandoned metal mine in Korea contained high concentrations of arsenic (As) and heavy metals [e.g., As: 67,336, Fe: 137,180, Cu: 764, Pb: 3,572, and Zn: 12,420 (mg/kg)]. US EPA method 6010 was an effective method for analyzing total arsenic and heavy metals concentrations. Arsenic in the mine tailings showed a high residual fraction of 89% by a sequential extraction. In Toxicity Characteristic Leaching Procedure (TCLP) and Korean Standard Leaching Test (KSLT), leaching concentrations of arsenic and heavy metals were very low [e.g., As (mg/L): 0.4 for TCLP and 0.2 for KSLT; cf. As criteria (mg/L): 5.0 for TCLP and 1.5 for KSLT]. PMID:20049231
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Evaluation of metal leaching using a single leach test such as the Toxicity Characteristic Leaching Procedure (TCLP) is often questionable. The pH, redox potential (Eh), particle size and contact time are critical variables in controlling metal stability, not accounted...
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Special Consolidated Checklists for Toxicity Characteristics Revisions
This checklist consolidates the changes to the Federal code addressed by the Toxicity Characteristic (TC) Rule [55 FR 11798; March 29, 1990; Revision Checklist 74] and subsequent revisions which have occurred through December 31, 2002.
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1997-11-01
TCL Target Compound List TCLP toxicity characteristic leachate procedure TPH Total Petroleum Hydrocarbon TRV toxicity reference value TSCA...controlled environment where temperature, nutrients, and oxygen can be controlled. Gaseous emissions and leachate can also be collected and treated...wood chip mixture was then spread over a gravel base enclosed in HDPE. The treatment beds were aerated with blowers and leachate was collected in a
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Hazardous waste status of discarded electronic cigarettes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Krause, Max J.; Townsend, Timothy G., E-mail: ttown@ufl.edu
Highlights: • Electronic cigarettes were tested using TCLP and WET. • Several electronic cigarette products leached lead at hazardous waste levels. • Lead was the only element that exceeded hazardous waste concentration thresholds. • Nicotine solution may cause hazardous waste classification when discarded unused. - Abstract: The potential for disposable electronic cigarettes (e-cigarettes) to be classified as hazardous waste was investigated. The Toxicity Characteristic Leaching Procedure (TCLP) was performed on 23 disposable e-cigarettes in a preliminary survey of metal leaching. Based on these results, four e-cigarette products were selected for replicate analysis by TCLP and the California Waste Extraction Testmore » (WET). Lead was measured in leachate as high as 50 mg/L by WET and 40 mg/L by TCLP. Regulatory thresholds were exceeded by two of 15 products tested in total. Therefore, some e-cigarettes would be toxicity characteristic (TC) hazardous waste but a majority would not. When disposed in the unused form, e-cigarettes containing nicotine juice would be commercial chemical products (CCP) and would, in the United States (US), be considered a listed hazardous waste (P075). While household waste is exempt from hazardous waste regulation, there are many instances in which such waste would be subject to regulation. Manufactures and retailers with unused or expired e-cigarettes or nicotine juice solution would be required to manage these as hazardous waste upon disposal. Current regulations and policies regarding the availability of nicotine-containing e-cigarettes worldwide were reviewed. Despite their small size, disposable e-cigarettes are consumed and discarded much more quickly than typical electronics, which may become a growing concern for waste managers.« less
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Lee, Seungbae; An, Jinsung; Kim, Young-Jin; Nam, Kyoungphile
2011-02-28
In situ stabilization of sediment-bound heavy metals has been proposed as an alternative to ex situ treatment due to the concerns on ecosystem disturbance and remediation cost. The present study was conducted to test the performance of birnessite, hydroxyapatite, and zeolite as stabilizing agents for Pb and Cd in sediment. The heavy metal binding capacity and strength of the stabilizing agents were determined by analyzing Langmuir model parameters. The three agents showed the similar binding capacity (i.e., maximum monolayer sorption constant, K(a)) ranging from 1.13 to 3.62×10(5) mg/kg for Pb and 1.07 to 1.33×10(5) mg/kg for Cd. In contrast, binding strength (i.e., binding energy constant, b) of birnessite and hydroxyapatite was about one order higher than that of zeolite. This is further supported by five-step sequential extraction data: more than 99 and 70% of freshly spiked Pb and Cd were present as not-readily extractable fractions in birnessite and hydroxyapatite, respectively while the fractions were 17.9 and 14.1% in zeolite. Toxicity Characteristic Leaching Procedure (TCLP) test was also conducted to verify the effectiveness of the heavy metal-stabilizing ability of birnessite and hydroxyapatite. Birnessite successfully retained both Pb and Cd against the leaching solution, satisfying the TCLP extract concentration limits (i.e., 5 and 1 mg/L, respectively). However, hydroxyapatite released about 223.7 mg/L of Cd into the solution, which greatly exceeded the limit. The toxicity test with Hyalella azteca showed that their survival rate increased by 92.5-100% when birnessite or hydroxyapatite was added to Pb- or Cd-spiked sediment as a stabilizing agent. Our data demonstrate the potential use of birnessite and hydroxyapatite as an effective in situ remediation means for heavy metal-contaminated sediment with minimal risk to the aquatic ecosystem. Copyright © 2011 Elsevier B.V. All rights reserved.
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Hazardous waste status of discarded electronic cigarettes.
Krause, Max J; Townsend, Timothy G
2015-05-01
The potential for disposable electronic cigarettes (e-cigarettes) to be classified as hazardous waste was investigated. The Toxicity Characteristic Leaching Procedure (TCLP) was performed on 23 disposable e-cigarettes in a preliminary survey of metal leaching. Based on these results, four e-cigarette products were selected for replicate analysis by TCLP and the California Waste Extraction Test (WET). Lead was measured in leachate as high as 50mg/L by WET and 40mg/L by TCLP. Regulatory thresholds were exceeded by two of 15 products tested in total. Therefore, some e-cigarettes would be toxicity characteristic (TC) hazardous waste but a majority would not. When disposed in the unused form, e-cigarettes containing nicotine juice would be commercial chemical products (CCP) and would, in the United States (US), be considered a listed hazardous waste (P075). While household waste is exempt from hazardous waste regulation, there are many instances in which such waste would be subject to regulation. Manufactures and retailers with unused or expired e-cigarettes or nicotine juice solution would be required to manage these as hazardous waste upon disposal. Current regulations and policies regarding the availability of nicotine-containing e-cigarettes worldwide were reviewed. Despite their small size, disposable e-cigarettes are consumed and discarded much more quickly than typical electronics, which may become a growing concern for waste managers. Copyright © 2015 Elsevier Ltd. All rights reserved.
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The leaching of lead from lead-based paint in landfill environments.
Wadanambi, Lakmini; Dubey, Brajesh; Townsend, Timothy
2008-08-30
Lead leaching from lead-based paint (LBP) was examined using standardized laboratory protocols and tests with leachate from actual and simulated landfill environments. Two different LBP samples were tested; leaching solutions included leachates from three municipal solid waste (MSW) landfills and three construction and demolition (C&D) debris landfills. The toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP) were also performed. Lead concentrations were many times higher using the TCLP compared to the SPLP and the landfill leachates. No significant difference (alpha=0.05) was observed in leached lead concentrations from the MSW landfill and C&D debris landfill leachates. The impact of other building materials present in LBP debris on lead leaching was examined by testing mixtures of LBP (2%) and different building materials (98%; steel, wood, drywall, concrete). The type of substrate present impacted lead leaching results, with concrete demonstrating the most dramatic impact; the lowest lead concentrations were measured in the presence of concrete under both TCLP and SPLP extractions.
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Leaching characteristics, ecotoxicity, and risk assessment based management of mine wastes
NASA Astrophysics Data System (ADS)
Kim, J.; Ju, W. J.; Jho, E. H.; Nam, K.; Hong, J. K.
2016-12-01
Mine wastes generated during mining activities in metal mines generally contain high concentrations of metals that may impose toxic effects to surrounding environment. Thus, it is necessary to properly assess the mining-impacted landscapes for management. The study investigated leaching characteristics, potential environmental effects, and human health risk of mine wastes from three different metal mines in South Korea (molybdenum mine, lead-zinc mine, and magnetite mine). The heavy metal concentrations in the leachates obtained by using the Korean Standard Test Method for Solid Wastes (STM), Toxicity Characteristics Leaching Procedure (TCLP), and Synthetic Precipitation Leaching Procedure (SPLP) met the Korea Waste Control Act and the USEPA region 3 regulatory levels accordingly, even though the mine wastes contained high concentrations of metals. Assuming that the leachates may get into nearby water sources, the leachate toxicity was tested using Daphnia Magna. The toxic unit (TU) values after 24 h and 48 h exposure of all the mine wastes tested met the Korea Allowable Effluent Water Quality Standards (TU<1). The column leaching test showed that the lead-zinc mine waste may have long-term toxic effects (TU>1 for the eluent at L/S of 30) implying that the long-term effect of mine wastes left in mining areas need to be assessed. Considering reuse of mine wastes as a way of managing mine wastes, the human health risk assessment of reusing the lead-zinc mine waste in industrial areas was carried out using the bioavailable fraction of the heavy metals contained in the mine wastes, which was determined by using the Solubility/Bioavailability Research Consortium method. There may be potential carcinogenic risk (9.7E-05) and non-carcinogenic risk (HI, Hazard Index of 1.0E+00) as CR≧1.0E-05 has carcinogenic risk and HI≧1.0E+00 has non-carcinogenic risk. Overall, this study shows that not only the concentration-based assessment but ecological toxic effect and human
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Mineral phases and metals in baghouse dust from secondary aluminum production.
Huang, Xiao-Lan; El Badawy, Amro M; Arambewela, Mahendranath; Adkins, Renata; Tolaymat, Thabet
2015-09-01
Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 μg L(-1) As; >1000 μg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities). Published by Elsevier Ltd.
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Treatment of RDX & HMX Plumes Using Mulch Biowalls
2008-08-01
Classification TAL Target Analyte List TCLP Toxicity Characteristic Leachate Procedure TNB 1,3,5-Trinitobenzene TNT 2,4,6-Trinitrotoluene TNX...active phytoremediation process in the source area (i.e., the former Pink Water pond area) that might already be contributing dissolved TOC...Technical Report i. Presence of other remediation technologies in the immediate vicinity No 4 No Yes; active phytoremediation in Pink
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Code of Federal Regulations, 2010 CFR
2010-07-01
... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene production wastes. (a) Effective December 19, 1994, the wastes specified in 40...
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Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Waste specific prohibitions-Soils... Prohibitions on Land Disposal § 268.32 Waste specific prohibitions—Soils exhibiting the toxicity characteristic... from land disposal: any volumes of soil exhibiting the toxicity characteristic solely because of the...
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Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Waste specific prohibitions-Soils... Prohibitions on Land Disposal § 268.32 Waste specific prohibitions—Soils exhibiting the toxicity characteristic... from land disposal: any volumes of soil exhibiting the toxicity characteristic solely because of the...
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Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Waste specific prohibitions-Soils... Prohibitions on Land Disposal § 268.32 Waste specific prohibitions—Soils exhibiting the toxicity characteristic... from land disposal: any volumes of soil exhibiting the toxicity characteristic solely because of the...
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Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Waste specific prohibitions-Soils... Prohibitions on Land Disposal § 268.32 Waste specific prohibitions—Soils exhibiting the toxicity characteristic... from land disposal: any volumes of soil exhibiting the toxicity characteristic solely because of the...
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Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Waste specific prohibitions-Soils... Prohibitions on Land Disposal § 268.32 Waste specific prohibitions—Soils exhibiting the toxicity characteristic... from land disposal: any volumes of soil exhibiting the toxicity characteristic solely because of the...
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Koralegedara, N H; Al-Abed, S R; Arambewela, M K J; Dionysiou, D D
2017-02-15
The interest in using Flue Gas Desulfurization Gypsum (FGDG) for land applications has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using recently approved EPA leaching methods (1313-1316). These methods employ various pH and liquid-solid (LS) ratios under batch leaching, column percolation and diffusion controlled release scenarios. Toxicity Characteristic Leaching Protocol (TCLP) and Synthetic Precipitation Leaching Protocol (SPLP) were used for comparison. The data obtained from new EPA methods provide broad insight into constituent release from FGDG and SF when compared to TCLP and SPLP. The release of toxic elements such as Hg, As, Pb, Co, Cd and Cr from SF was negligible. High release of B from FGDG was observed under all tested conditions; however, its release from SF was low. Both FGDG and SF released Se under all pH conditions (2-13) and LS ratios (1-10) in low concentrations (0.02-0.2mg/L). The data from this study could be used to investigate potential use of "modern" FGDG for new beneficial land applications. Published by Elsevier B.V.
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Moon, Deok Hyun; Wazne, Mahmoud; Yoon, In-Ho; Grubb, Dennis G
2008-11-30
A stabilization/solidification (S/S) process for arsenic (As) contaminated soils was evaluated using cement kiln dust (CKD). Laboratory-prepared slurries, made of either kaolinite or montmorillonite, and field soils spiked with either As(3+) or As(5+) were prepared and treated with CKD ranging from 10 to 25 wt%. Sodium arsenite and sodium arsenate at 0.1 wt% were used to simulate arsenite (As(3+)) and arsenate (As(5+)) source contamination in soils, respectively. The effectiveness of treatment was evaluated at curing periods of 1- and 7-days based on the toxicity characteristic leaching procedure (TCLP). As-CKD and As-clay-CKD slurries were also spiked at 10 wt% to evaluate As immobilization mechanism using X-ray powder diffraction (XRPD) analyses. Overall, the TCLP results showed that only the As(5+) concentrations in kaolinite amended with 25 wt% CKD after 1 day of curing were less than the TCLP regulatory limit of 5mg/L. Moreover, at 7 days of curing, all As(3+) and As(5+) concentrations obtained from kaolinite soils were less than the TCLP criteria. However, none of the CKD-amended montmorillonite samples satisfied the TCLP-As criteria at 7 days. Only field soil samples amended with 20 wt% CKD complied with the TCLP criteria within 1 day of curing, where the source contamination was As(5+). XRPD and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results showed that Ca-As-O and NaCaAsO(4).7.5H(2)O were the primary phases responsible for As(3+) and As(5+) immobilization in the soils, respectively.
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Treatment of waste printed wire boards in electronic waste for safe disposal.
Niu, Xiaojun; Li, Yadong
2007-07-16
The printed wire boards (PWBs) in electronic waste (E-waste) have been found to contain large amounts of toxic substances. Studies have concluded that the waste PWBs are hazardous wastes because they fails the toxicity characteristic leaching procedure (TCLP) test with high level of lead (Pb) leaching out. In this study, two treatment methods - high-pressure compaction and cement solidification - were explored for rendering the PWBs into non-hazardous forms so that they may be safely disposed or used. The high-pressure compaction method could turn the PWBs into high-density compacts with significant volume reduction, but the impact resistance of the compacts was too low to keep them intact in the environment for a long run. In contrast, the cement solidification could turn the PWBs into strong monoliths with high impact resistance and relatively high compressive strength. The leaching of the toxic heavy metal Pb from the solidified samples was evaluated by both a dynamic leaching test and the TCLP test. The dynamic leaching results revealed that Pb could be effectively confined in the solidified products under very harsh environmental conditions. The TCLP test results showed that the leaching level of Pb was far below the regulatory level of 5mg/L, suggesting that the solidified PWBs are no longer hazardous. It was concluded that the cement solidification is an effective way to render the waste PWBs into environmentally benign forms so that they can be disposed of as ordinary solid wastes or beneficially used in the place of concrete in some applications.
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Code of Federal Regulations, 2014 CFR
2014-07-01
... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...
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Code of Federal Regulations, 2013 CFR
2013-07-01
... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...
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Code of Federal Regulations, 2012 CFR
2012-07-01
... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...
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Code of Federal Regulations, 2011 CFR
2011-07-01
... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...
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A simple scheme to determine potential aquatic metal toxicity from mining wastes
Wildeman, T.R.; Smith, K.S.; Ranville, J.F.
2007-01-01
A decision tree (mining waste decision tree) that uses simple physical and chemical tests has been developed to determine whether effluent from mine waste material poses a potential toxicity threat to the aquatic environment. For the chemical portion of the tree, leaching tests developed by the United States Geological Survey, the Colorado Division of Minerals and Geology (Denver, CO), and a modified 1311 toxicity characteristic leaching procedure (TCLP) test of the United States Environmental Protection Agency have been extensively used as a surrogate for readily available metals that can be released into the environment from mining wastes. To assist in the assessment, element concentration pattern graphs (ECPG) are produced that compare concentrations of selected groups of elements from the three leachates and any water associated with the mining waste. The MWDT makes a distinction between leachates or waters with pH less than or greater than 5. Generally, when the pH values are below 5, the ECPG of the solutions are quite similar, and potential aquatic toxicity from cationic metals, such as Pb, Cu, Zn, Cd, and Al, is assumed. Below pH 5, these metals are mostly dissolved, generally are not complexed with organic or inorganic ligands, and hence are more bioavailable. Furthermore, there is virtually no carbonate alkalinity at pH less than 5. All of these factors promote metal toxicity to aquatic organisms. On the other hand, when the pH value of the water or the leachates is above 5, the ECPG from the solutions are variable, and inferred aquatic toxicity depends on factors in addition to the metals released from the leaching tests. Hence, leachates and waters with pH above 5 warrant further examination of their chemical composition. Physical ranking criteria provide additional information, particularly in areas where waste piles exhibit similar chemical rankings. Rankings from physical and chemical criteria generally are not correlated. Examples of how this
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Wang, Hui-Gang; Zhang, Mei; Guo, Min
2017-10-05
One-step solid state reaction method was proposed for the first time to realize the transformation of the Zn-containing EAFD from hazardous solid waste to multi-metal doped ferrite with enhanced magnetic property. The effect of Zn-containing EAFD to NiCl 2 ·6H 2 O mass ratio (R ZE/N , g·g -1 ) on the phases transformation was investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Raman spectroscopy. The as-synthesized samples were treated by toxicity characteristic leaching procedure (TCLP). It is shown that the TCPL played a key role in determining both the purity and toxicity of the obtained ferrites. The pure metal doped Ni-Zn ferrite with higher saturation magnetization (Ms, 56.8 emu·g -1 ) and lower coercivity (Hc, 58.5Oe) was gained under the optimum conditions. And the pure ferrite was a green product according to the TCLP and EN12457 standards. Moreover, the evaluation of environmental impact and the recovery ratio of the dust were also discussed. Copyright © 2017. Published by Elsevier B.V.
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Effect of pH, competitive anions and NOM on the leaching of arsenic from solid residuals.
Ghosh, Amlan; Sáez, A Eduardo; Ela, Wendell
2006-06-15
Implementation of the new arsenic MCL in 2006 will lead to the generation of an estimated 6 million pounds of arsenic-bearing solid residuals (ABSRs) every year, which will be disposed predominantly in non-hazardous landfills. The Toxicity Characteristic Leaching Procedure (TCLP) is typically used to assess whether a waste is hazardous and most solid residuals pass the TCLP. However, recent research shows the TCLP significantly underestimates arsenic mobilization in landfills. A variety of compositional dissimilarities between landfill leachates and the TCLP extractant solution likely play a role. Among the abiotic factors likely to play a key role in arsenic remobilization/leaching from solid sorbents are pH, and the concentrations of natural organic matter (NOM) and anions like phosphate, bicarbonate, sulfate and silicate. This study evaluates the desorption of arsenic from actual treatment sorbents, activated alumina (AA) and granular ferric hydroxide (GFH), which are representative of those predicted for use in arsenic removal processes, and as a function of the specific range of pH and concentrations of the competitive anions and NOM found in landfills. The influence of pH is much more significant than that of competing anions or NOM. An increase in one unit of pH may increase the fraction of arsenic leached by 3-4 times. NOM and phosphate replace arsenic from sorbent surface sites up to three orders of magnitude more than bicarbonate, sulfate and silicate, on a per mole basis. Effects of anions are neither additive nor purely competitive. Leaching tests, which compare the fraction of arsenic mobilized by the TCLP vis-a-vis an actual or more realistic synthetic landfill leachate, indicate that higher pH, and greater concentrations of anions and NOM are all factors, but of varying significance, in causing higher extraction in landfill and synthetic leachates than the TCLP.
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Residual mercury content and leaching of mercury and silver from used amalgam capsules.
Stone, M E; Pederson, E D; Cohen, M E; Ragain, J C; Karaway, R S; Auxer, R A; Saluta, A R
2002-06-01
The objective of this investigation was to carry out residual mercury (Hg) determinations and toxicity characteristic leaching procedure (TCLP) analysis of used amalgam capsules. For residual Hg analysis, 25 capsules (20 capsules for one brand) from each of 10 different brands of amalgam were analyzed. Total residual Hg levels per capsule were determined using United States Environmental Protection Agency (USEPA) Method 7471. For TCLP analysis, 25 amalgam capsules for each of 10 brands were extracted using a modification of USEPA Method 1311. Hg analysis of the TCLP extracts was done with USEPA Method 7470A. Analysis of silver (Ag) concentrations in the TCLP extract was done with USEPA Method 6010B. Analysis of the residual Hg data resulted in the segregation of brands into three groups: Dispersalloy capsules, Group A, retained the most Hg (1.225 mg/capsule). These capsules were the only ones to include a pestle. Group B capsules, Valliant PhD, Optaloy II, Megalloy and Valliant Snap Set, retained the next highest amount of Hg (0.534-0.770 mg/capsule), and were characterized by a groove in the inside of the capsule. Group C, Tytin regular set double-spill, Tytin FC, Contour, Sybraloy regular set, and Tytin regular set single-spill retained the least amount of Hg (0.125-0.266 mg/capsule). TCLP analysis of the triturated capsules showed Sybraloy and Contour leached Hg at greater than the 0.2 mg/l Resource Conservation and Recovery Act (RCRA) limit. This study demonstrated that residual mercury may be related to capsule design features and that TCLP extracts from these capsules could, in some brands, exceed RCRA Hg limits, making their disposal problematic. At current RCRA limits, the leaching of Ag is not a problem.
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Leaching behavior and chemical stability of copper butyl xanthate complex under acidic conditions.
Chang, Yi Kuo; Chang, Juu En; Chiang, Li Choung
2003-08-01
Although xanthate addition can be used for treating copper-containing wastewater, a better understanding of the leaching toxicity and the stability characteristics of the copper xanthate complexes formed is essential. This work was undertaken to evaluate the leaching behavior of copper xanthate complex precipitates by means of toxicity characteristics leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) using 1 N acetic acid solution as the leachant. Also, the chemical stability of the copper xanthate complex during extraction has been examined with the studying of variation of chemical structure using UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopies (XPS). Both TCLP and SDLT results showed that a negligible amount of copper ion was leached out from the copper xanthate complex precipitate, indicating that the complex exhibited a high degree of copper leaching stability under acidic conditions. Nevertheless, chemical structure of the copper xanthate complex precipitate varied during the leaching tests. XPS data suggested that the copper xanthate complex initially contained both cupric and cuprous xanthate, but the unstable cupric xanthate change to the cuprous form after acid extraction, indicating the cuprous xanthate to be the final stabilizing structure. Despite that, the changes of chemical structure did not induce the rapid leaching of copper from the copper xanthate complex.
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Environmental Compliance Inspection Checklist for Shipbuilding Facilities
1992-04-01
regulations will most likely apply to the mixing and application of tributyltin ( TBT )-based and other anti-fouling paints, as well as routine...Pollution Discharge Elimination System Small Quantity Generator 94 TBT Tributyltin TCLP Toxicity Characteristic Leaching Procedure TPQ Threshold...of at the yard? If “YES,” continue. 8.1.2 Are pesticides applied by yard personnel? If “YES," describe the type(s) used ( TBT paint etc.) and where
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Hira, Meenakshi; Yadav, Sudesh; Morthekai, P; Linda, Anurag; Kumar, Sushil; Sharma, Anupam
2018-01-15
The prolonged use of old fashioned gadgets, especially mobile phones, is declining readily with the advancement in technology which ultimately lead to generation of e-waste. The present study investigates the concentrations of nine metals (Ba, Cd, Cr, Cu, Fe, Ni, Pb, Sn, and Zn) in various components of the mobile phones using Toxicity Characteristic Leaching Procedure (TCLP), Waste Extraction Test (WET) and Synthetic Precipitation Leaching Procedure (SPLP). The results were compared with the threshold limits for hazardous waste defined by the California Department of Toxic Substances Control (CDTSC) and United States Environmental Protection Agency (USEPA). The average concentrations of metals were found high in PWBs. WET was found relatively aggressive as compared to TCLP and SPLP. Redundancy analysis (RDA) suggests that part of mobile, extraction test, manufacturer, mobile model and year of manufacturing explain 34.66% of the variance. According to the present study, waste mobile phones must be considered as hazardous due to the potential adverse impact of toxic metals on human health and environment. However, mobile phones can be an asset as systematic extraction and recycling could reduce the demand of primary metals mining and conserve the natural resources. Copyright © 2017 Elsevier B.V. All rights reserved.
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The effects of characteristics of substituents on toxicity of the nitroaromatics: HiT QSAR study
NASA Astrophysics Data System (ADS)
Kuz'min, Victor E.; Muratov, Eugene N.; Artemenko, Anatoly G.; Gorb, Leonid; Qasim, Mohammad; Leszczynski, Jerzy
2008-10-01
The present study applies the Hierarchical Technology for Quantitative Structure-Activity Relationships (HiT QSAR) for (i) evaluation of the influence of the characteristics of 28 nitroaromatic compounds (some of which belong to a widely known class of explosives) as to their toxicity; (ii) prediction of toxicity for new nitroaromatic derivatives; (iii) analysis of the effects of substituents in nitroaromatic compounds on their toxicity in vivo. The 50% lethal dose concentration for rats (LD50) was used to develop the QSAR models based on simplex representation of molecular structure. The preliminary 1D QSAR results show that even the information on the composition of molecules reveals the main tendencies of changes in toxicity. The statistic characteristics for partial least squares 2D QSAR models are quite satisfactory ( R 2 = 0.96-0.98; Q 2 = 0.91-0.93; R 2 test = 0.89-0.92), which allows us to carry out the prediction of activity for 41 novel compounds designed by the application of new combinations of substituents represented in the training set. The comprehensive analysis of toxicity changes as a function of substituent position and nature was carried out. Molecular fragments that promote and interfere with toxicity were defined on the basis of the obtained models. It was shown that the mutual influence of substituents in the benzene ring plays a crucial role regarding toxicity. The influence of different substituents on toxicity can be mediated via different C-H fragments of the aromatic ring.
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Basic characteristics of leachate produced by various washing processes for MSWI ashes in Taiwan.
Yang, Renbo; Liao, Wing-Ping; Wu, Pin-Han
2012-08-15
Approximately 19.2% of Taiwan's municipal solid waste (MSW) that passes through incineration disposal is converted into ashes (including bottom ash and fly ash). Although bottom ash can pass nearly all of the standards of the toxicity characteristic leaching procedure (TCLP), its high chloride content makes its reuse limited; it generally cannot be used as a fine aggregate material in concrete applications. This research examined washing four types of bottom ash (BA) and fly ash (FA) with water to reduce their chloride content. The optimal water intensity for washing pretreated bottom ash was found to be 7-8L of water per kg of bottom ash, and the optimal water intensity for washing untreated fly ash was found to be 20-25 L of water per kg of fly ash. Based on regression analyses of the chloride concentrations of the leachates and their electrical conductivity (EC) values, each MSW incineration plant has its own ash characteristics as well as a specific regression line in bottom or fly ash leachate. Clearly, it is possible to monitor the EC values of the leachates online by estimation from regression equations to determine the chloride concentrations in the leachates. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.
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Lim, Jung Eun; Sung, Jwa Kyung; Sarkar, Binoy; Wang, Hailong; Hashimoto, Yohey; Tsang, Daniel C W; Ok, Yong Sik
2017-04-01
Metal stabilization using soil amendments is an extensively applied, economically viable and environmentally friendly remediation technique. The stabilization of Pb, Zn and As in contaminated soils was evaluated using natural starfish (NSF) and calcined starfish (CSF) wastes at different application rates (0, 2.5, 5.0 and 10.0 wt%). An incubation study was conducted over 14 months, and the efficiency of stabilization for Pb, Zn and As in soil was evaluated by the toxicity characteristic leaching procedure (TCLP) test. The TCLP-extractable Pb was reduced by 76.3-100 and 91.2-100 % in soil treated with NSF and CSF, respectively. The TCLP-extractable Zn was also reduced by 89.8-100 and 93.2-100 % in soil treated with NSF and CSF, respectively. These reductions could be associated with the increased metal adsorption and the formation of insoluble metal precipitates due to increased soil pH following application of the amendments. However, the TCLP-extractable As was increased in the soil treated with NSF, possibly due to the competitive adsorption of phosphorous. In contrast, the TCLP-extractable As in the 10 % CSF treatment was not detectable because insoluble Ca-As compounds might be formed at high pH values. Thermodynamic modeling by visual MINTEQ predicted the formation of ettringite (Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26H 2 O) and portlandite (Ca(OH) 2 ) in the 10 % CSF-treated soil, while SEM-EDS analysis confirmed the needle-like structure of ettringite in which Pb was incorporated and stabilized in the 10 % CSF treatment.
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Strength, leachability and microstructure characteristics of cement-based solidified plating sludge
DOE Office of Scientific and Technical Information (OSTI.GOV)
Asavapisit, Suwimol; Naksrichum, Siripat; Harnwajanawong, Naraporn
2005-06-01
The solidification of the stabilized zinc-cyanide plating sludge was carried out using ordinary Portland cement (OPC) and pulverized fuel ash (PFA) as solidification binders. The plating sludge were used at the level of 0%, 10%, 20% and 30% dry weight, and PFA was used to replace OPC at 0%, 10%, 20% and 30% dry weight, respectively. Experimental results showed that a significant reduction in strength was observed when the plating sludge was added to both the OPC and OPC/PFA binders, but the negative effect was minimized when PFA was used as part substitute for OPC. SEM observation reveals that themore » deposition of the plating sludge on the surface of the clinkers and PFA could be the cause for hydration retardation. In addition, calcium zinc hydroxide hydrate complex and the unreacted di- and tricalcium silicates were the major phases in X-ray diffraction (XRD) patterns of the solidified plating waste hydrated for 28 days, although the retardation effect on hydration reactions but Cr concentration in toxicity characteristic leaching procedure (TCLP) leachates was lower than the U.S. EPA regulatory limit.« less
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Mineral phases and metals in baghouse dust from secondary ...
Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 µgL-1 As; >1000 µgL-1 Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities). The objective of this study was to investigate BHD from SAP facilities in the U.S. by determining the mineral phases and the metal (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Se and Zn) content of the sample
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Scoping candidate minerals for stabilization of arsenic-bearing solid residuals.
Raghav, Madhumitha; Shan, Jilei; Sáez, A Eduardo; Ela, Wendell P
2013-12-15
Arsenic Crystallization Technology (ACT) is a potentially eco-friendly, effective technology for stabilization of arsenic-bearing solid residuals (ABSRs). The strategy is to convert ABSRs generated by water treatment facilities into minerals with a high arsenic capacity and long-term stability in mature, municipal solid waste landfills. Candidate minerals considered in this study include scorodite, arsenate hydroxyapatites, ferrous arsenates (symplesite-type minerals), tooeleite, and arsenated-schwertmannite. These minerals were evaluated as to ease of synthesis, applicability to use of iron-based ABSRs as a starting material, and arsenic leachability. The Toxicity Characteristic Leaching Procedure (TCLP) was used for preliminary assessment of candidate mineral leaching. Minerals that passed the TCLP and whose synthesis route was promising were subjected to a more aggressive leaching test using a simulated landfill leachate (SLL) solution. Scorodite and arsenate hydroxyapatites were not considered further because their synthesis conditions were not found to be favorable for general application. Tooeleite and silica-amended tooeleite showed high TCLP arsenic leaching and were also not investigated further. The synthesis process and leaching of ferrous arsenate and arsenated-schwertmannite were promising and of these, arsenated-schwertmannite was most stable during SLL testing. The latter two candidate minerals warrant synthesis optimization and more extensive testing. Copyright © 2013 Elsevier B.V. All rights reserved.
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Scoping Candidate Minerals for Stabilization of Arsenic-Bearing Solid Residuals
Raghav, Madhumitha; Shan, Jilei; Sáez, A. Eduardo; Ela, Wendell P.
2014-01-01
Arsenic Crystallization Technology (ACT) is a potentially eco-friendly, effective technology for stabilization of arsenic-bearing solid residuals (ABSRs). The strategy is to convert ABSRs generated by water treatment facilities into minerals with a high arsenic capacity and long-term stability in mature, municipal solid waste landfills. Candidate minerals considered in this study include scorodite, arsenate hydroxyapatites, ferrous arsenates (symplesite-type minerals), tooeleite, and arsenated-schwertmannite. These minerals were evaluated as to ease of synthesis, applicability to use of iron-based ABSRs as a starting material, and arsenic leachability. The Toxicity Characteristic Leaching Procedure (TCLP) was used for preliminary assessment of candidate mineral leaching. Minerals that passed the TCLP and whose synthesis route was promising were subjected to a more aggressive leaching test using a simulated landfill leachate (SLL) solution. Scorodite and arsenate hydroxyapatites were not considered further because their synthesis conditions were not found to be favorable for general application. Tooeleite and silica-amended tooeleite showed high TCLP arsenic leaching and were also not investigated further. The synthesis process and leaching of ferrous arsenate and arsenated-schwertmannite were promising and of these, arsenated-schwertmannite was most stable during SLL testing. The latter two candidate minerals warrant synthesis optimization and more extensive testing. PMID:24231323
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Karamalidis, Athanasios K; Voudrias, Evangelos A
2004-01-01
The oily sludge produced by petroleum refineries is classified as a solid hazardous waste, according to European regulations. The objective of this work was to investigate whether stabilization/solidification can be used as a management method for the oily sludge. The sludge samples used originated from a petroleum-storing tank and a centrifuge unit of two Greek refineries. The experiments were designed to study the leachability of the heavy metals Pb, Cr, Cd, Ni, and Cu, which are contained in the sludge, using the Toxicity Characteristic Leaching Procedure (TCLP). Despite the fact that the metals were immobilized in a cement-based environment in the presence of organic load, leaching tests have shown a low metal leachability, less than 5%. Acid Neutralizing Capacity (ANC) tests were employed in order to estimate the acid resistance of the stabilized/solidified waste. In addition to ANC, a sequential TCLP test was employed in order to understand how the pH affects the leachability of Ni from the stabilized/solidified specimen.
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Solidification and stabilization of the incinerated wastewater sludge from textile industry
NASA Astrophysics Data System (ADS)
Aziz, Hamidi Abdul; Ghazali, Miskiah Fadzilah; Omran, Abdelnaser; Umar, Muhammad
2017-10-01
This paper describes the investigation of solidification and stabilization (S/S) process for the safe disposal of incinerated wastewater sludge produced from a textile industry in Penang, Malaysia. Physical and chemical properties of the samples were first characterized. Various ratios of ordinary Portland cement (OPC) as a binder were used to immobilize the metals. The leachability of metals in these cement-based waste materials was studied by standard toxicity characteristic leaching procedure (TCLP) and the mechanical strength was tested by a compressive strength test. TCLP results showed the ability of OPC to immobilize various metals such as Zn, Cu, Fe, Al, Ti, and K within the limits set by USEPA and Malaysia Environment Quality Act, 1974. However, the strength of the solidified matrixes was generally lower than the control specimens, ranging from 1-23 Mpa, which was well above the specified limit of 414 kPa for such matrices for their disposal in landfills.
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Comparison of metal lability in air-dried and fresh dewatered drinking water treatment residuals.
Wang, Changhui; Pei, Yuansheng; Zhao, Yaqian
2015-01-01
In this work, the labilities of Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr, V and Zn in air-dried (for 60 days) and fresh dewatered WTRs were compared using the Toxicity Characteristic Leaching Procedure (TCLP), fractionation, in vitro digestion and a plant enrichment test. The results showed that the air-dried and fresh dewatered WTRs had different properties, e.g., organic matter composition and available nutrients. The air-dried and fresh dewatered WTRs were non-haf zardous according to the TCLP assessment method used in the United States; however, the metals in the two types of WTRs had different lability. Compared with the metals in the fresh dewatered WTRs, those in the air-dried WTRs tended to be in more stable fractions and also exhibited lower bioaccessibility and bioavailability. Therefore, air-drying can decrease the metal lability and thereby reduce the potential metal pollution risk of WTRs.
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Al-Abed, S. R.; Hageman, P.L.; Jegadeesan, G.; Madhavan, N.; Allen, D.
2006-01-01
Evaluation of metal leaching using a single leach test such as the Toxicity Characteristic Leaching Procedure (TCLP) is often questionable. The pH, redox potential (Eh), particle size and contact time are critical variables in controlling metal stability, not accounted for in the TCLP. This paper compares the leaching behavior of metals in mineral processing waste via short-term extraction tests such as TCLP, Field Leach Test (FLT) used by USGS and deionized water extraction tests. Variation in the extracted amounts was attributed to the use of different particle sizes, extraction fluid and contact time. In the controlled pH experiments, maximum metal extraction was obtained at acidic pH for cationic heavy metals such as Cu, Pb and Zn, while desorption of Se from the waste resulted in high extract concentrations in the alkaline region. Precipitation of iron, caused by a pH increase, probably resulted in co-precipitation and immobilization of Cu, Pb and Zn in the alkaline pH region. A sequential extraction procedure was performed on the original waste and the solid residue from the Eh-pH experiments to determine the chemical speciation and distribution of the heavy metals. In the as-received waste, Cu existed predominantly in water soluble or sulfidic phases, with no binding to carbonates or iron oxides. Similar characteristics were observed for Pb and Zn, while Se existed mostly associated with iron oxides or sulfides. Adsorption/co-precipitation of Cu, Se and Pb on precipitated iron hydroxides was observed in the experimental solid residues, resulting in metal immobilization above pH 7.
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Leaching of CCA-treated wood: implications for waste disposal.
Townsend, Timothy; Tolaymat, Thabet; Solo-Gabriele, Helena; Dubey, Brajesh; Stook, Kristin; Wadanambi, Lakmini
2004-10-18
Leaching of arsenic, chromium, and copper from chromated copper arsenate (CCA)-treated wood poses possible environmental risk when disposed. Samples of un-weathered CCA-treated wood were tested using a variety of the US regulatory leaching procedures, including the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), extraction procedure toxicity method (EPTOX), waste extraction test (WET), multiple extraction procedure (MEP), and modifications of these procedures which utilized actual MSW landfill leachates, a construction and demolition (C and D) debris leachate, and a concrete enhanced leachate. Additional experiments were conducted to assess factors affecting leaching, such as particle size, pH, and leaching contact time. Results from the regulatory leaching tests provided similar results with the exception of the WET, which extracted greater quantities of metals. Experiments conducted using actual MSW leachate, C and D debris leachate, and concrete enhanced leachate provided results that were within the same order of magnitude as results obtained from TCLP, SPLP, and EPTOX. Eleven of 13 samples of CCA-treated dimensional lumber exceeded the US EPA's toxicity characteristic (TC) threshold for arsenic (5 mg/L). If un-weathered arsenic-treated wood were not otherwise excluded from the definition of hazardous waste, it frequently would require management as such. When extracted with simulated rainwater (SPLP), 9 of the 13 samples leached arsenic at concentrations above 5 mg/L. Metal leachability tended to increase with decreasing particle size and at pH extremes. All three metals leached above the drinking water standards thus possibly posing a potential risk to groundwater. Arsenic is a major concern from a disposal point of view with respect to ground water quality.
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1QCY17 Saltstone waste characterization analysis
DOE Office of Scientific and Technical Information (OSTI.GOV)
Johnson, F. C.
2017-07-25
In the first quarter of calendar year 2017, a salt solution sample was collected from Tank 50 on January 16, 2017 in order to meet South Carolina (SC) Regulation 61-107.19 Part I C, “Solid Waste Management: Solid Waste Landfills and Structural Fill – General Requirements” and the Saltstone Disposal Facility Class 3 Landfill Permit. The Savannah River National Laboratory (SRNL) was requested to prepare and ship saltstone samples to a United States Environmental Protection Agency (EPA) certified laboratory to perform the Toxicity Characteristic Leaching Procedure (TCLP) and subsequent characterization.
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Tu, Yao-Jen; Chang, Chien-Kuei; You, Chen-Feng; Lou, Jie-Chung
2010-09-15
A method in combination of acid leaching, chemical exchange and ferrite process was applied to recycle copper and confer higher chemical stability to the sludge generated from etching process in printed circuit board industry. Ninety-five percent copper could be recycled in the form of powder from the sludge. Moreover, not only the wastewater after chemical exchange can be treated to fulfill the effluent standard, but also the sludge can satisfy the toxicity characteristic leaching procedure (TCLP) limits made by Taiwan's environmental protection administration. Copyright 2010 Elsevier B.V. All rights reserved.
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Hoy, Menglim; Horpibulsuk, Suksun; Rachan, Runglawan; Chinkulkijniwat, Avirut; Arulrajah, Arul
2016-12-15
In this research, a low-carbon stabilization method was studied using Recycled Asphalt Pavement (RAP) and Fly Ash (FA) geopolymers as a sustainable pavement material. The liquid alkaline activator (L) is a mixture of sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH), and high calcium FA is used as a precursor to synthesize the FA-RAP geopolymers. Unconfined Compressive Strength (UCS) of RAP-FA blend and RAP-FA geopolymer are investigated and compared with the requirement of the national road authorities of Thailand. The leachability of the heavy metals is measured by Toxicity Characteristic Leaching Procedure (TCLP) and compared with international standards. The Scanning Electron Microscopy (SEM) analysis of RAP-FA blend indicates the Calcium Aluminate (Silicate) Hydrate (C-A-S-H) formation, which is due to a reaction between the high calcium in RAP and high silica and alumina in FA. The low geopolymerization products (N-A-S-H) of RAP-FA geopolymer at NaOH/Na 2 SiO 3 =100:0 are detected at the early 7days of curing, hence its UCS is lower than that of RAP-FA blend. The 28-day UCS of RAP-FA geopolymers at various NaOH/Na 2 SiO 3 ratios are significantly higher than that of the RAP-FA blend, which can be attributed to the development of geopolymerization reactions. With the input of Na 2 SiO 3 , the highly soluble silica from Na 2 SiO 3 reacted with leached silica and alumina from FA and RAP and with free calcium from FA and RAP; hence the coexistence of N-A-S-H gel and C-A-S-H products. Therefore, the 7-day UCS values of RAP-FA geopolymers increase with decreasing NaOH/Na 2 SiO 3 ratio. TCLP results demonstrated that there is no environmental risk for both RAP-FA blends and RAP-FA geopolymers in road construction. The geopolymer binder reduces the leaching of heavy metal in RAP-FA mixture. The outcomes from this research will promote the move toward increased applications of recycled materials in a sustainable manner in road construction. Copyright © 2016
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Assessing Metal Mobilization from Industrially Lead ...
A series of leaching and partitioning tests (Toxicity Characteristic Leaching Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP), Controlled Acidity Leaching Protocol (CALP), Acid Neutralization Capacity (ANC), and sequential extraction) were applied to three different soils to study potential mobility of metals into groundwater. Two of these soils were lead (Pb)-contaminated soils (Hotspot 1 and Hotspot 2) collected from an urban site associated with lead smelting and other industrial operations. The third sample (Stockpile) was soil affected by previous contamination in the area, removed from residential properties, stockpiled, and selected to be used as fill material in the studied site. The TCLP and CALP showed that Pb could be released from both hotspots, but were not released in the acidic rainfall extraction fluid of the SPLP. The sequential extraction showed that Pb in the hotspot soils was associated with the carbonate fraction, while As was associated with the Fe and Mn oxides. The stockpile released traces of Pb or As in the TCLP and CALP, but the ANC only released Pb under acidic conditions and the SPLP did not release Pb or As. Overall, the projected repository with Stockpile would not pose imminent danger to groundwater because, under the expected environmental conditions, Pb and As tend to remain in the solid phase. The objectives of this study were to determine if the stockpiled soil was suitable for the intended fill purpo
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Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment.
Clancy, Tara M; Snyder, Kathryn V; Reddy, Raghav; Lanzirotti, Antonio; Amrose, Susan E; Raskin, Lutgarde; Hayes, Kim F
2015-12-30
Cement stabilization of arsenic-bearing wastes is recommended to limit arsenic release from wastes following disposal. Such stabilization has been demonstrated to reduce the arsenic concentration in the Toxicity Characteristic Leaching Procedure (TCLP), which regulates landfill disposal of arsenic waste. However, few studies have evaluated leaching from actual wastes under conditions similar to ultimate disposal environments. In this study, land disposal in areas where flooding is likely was simulated to test arsenic release from cement stabilized arsenic-bearing iron oxide wastes. After 406 days submersed in chemically simulated rainwater, <0.4% of total arsenic was leached, which was comparable to the amount leached during the TCLP (<0.3%). Short-term (18 h) modified TCLP tests (pH 3-12) found that cement stabilization lowered arsenic leaching at high pH, but increased leaching at pH<4.2 compared to non-stabilized wastes. Presenting the first characterization of cement stabilized waste using μXRF, these results revealed the majority of arsenic in cement stabilized waste remained associated with iron. This distribution of arsenic differed from previous observations of calcium-arsenic solid phases when arsenic salts were stabilized with cement, illustrating that the initial waste form influences the stabilized form. Overall, cement stabilization is effective for arsenic-bearing wastes when acidic conditions can be avoided. Copyright © 2015 Elsevier B.V. All rights reserved.
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Physicochemical characteristics and toxic effects of ozone-oxidized black carbon particles
NASA Astrophysics Data System (ADS)
Li, Qian; Shang, Jing; Zhu, Tong
2013-12-01
Black carbon (BC) or soot particles formed by combustion are ubiquitous in the atmosphere and have a significant effect on climate and human health. Oxidation can change the physicochemical characteristics of BC, thereby increasing its toxicity. The physicochemical properties of BC and ozone-oxidized BC are investigated in this study through transmission electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, ultraviolet-visible spectrophotometry, and electron paramagnetic resonance. The contents of oxygen-containing functional groups, hydrophilicity, water-soluble organic compounds, and free radicals increased after ozone treatment. The redox capacity and cytotoxicity of BC particles were enhanced by ozone oxidation as detected by dithiothreitol (DTT) and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assays. The redox activities of different BC particles are compared. Particle phase contributed significantly to total redox activity as detected by the DTT assay. Results indicate that BC particles that have undergone aging in the atmosphere may be more toxic and harmful to human health.
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Fang, Binbin; Guo, Jing; Li, Fuxing; Giesy, John P; Wang, Lianjun; Shi, Wei
2017-02-01
Industrialized development of the Yangtze River Delta, China, has resulted in larger amounts of wastes, including sludges from treatment of these wastes. Methods to manage and dispose, including reuse were urgently needed. Sludge and reused products were collected from two largest factories, KEYUAN and HENGJIA where treated sludges were turned into bricks or sludge cake to be placed in landfills, respectively. Metals and organic compounds were quantified in sludges and leachates assessed by use of toxicity characterized leaching procedure (TCLP) while acute toxicity was determined by Daphnia magna. Nine metals were detected in all raw sludges with concentrations of Cr and Ni exceeding Chinese standards. For sludge leachate, concentrations of metals were all less than Chinese standards, which changed little after being made into cake by HENGJIA, but were significantly less after being made into brick by KEYUAN. Toxicity units (TU) for all samples are greater than 1.0 indicating that they are potentially toxic to aquatic organisms. TUs changed little after being made into filter cake, but were 10-fold less after being made into bricks. Cr and Ni contributed most to the total toxicity followed by Zn and Cu. Making of sludges into K-brick 1 resulted in better inactivation of contaminants, which resulted in less toxic potencies. So that is the recommended method for handling of industrial sludges. To further assure their safe reuse, additional research on identification of key toxicants and potential hazards, based on additional endpoints, by combining bio-tests and chemical analysis should be done for reused sludges. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Comparative Effects of Biochar, Slag and Ferrous-Mn Ore on Lead and Cadmium Immobilization in Soil.
Mehmood, Sajid; Rizwan, Muhammad; Bashir, Saqib; Ditta, Allah; Aziz, Omar; Yong, Li Zhe; Dai, Zhihua; Akmal, Muhammad; Ahmed, Waqas; Adeel, Muhammad; Imtiaz, Muhammad; Tu, Shuxin
2018-02-01
A variety of remediation approaches have been applied to the heavy metals-contaminated soils, however, the immobilization of metals in co-contaminated soils still not cleared. Therefore, an incubation study was conducted to evaluate the instantaneous effects of different concentrations of biochar (BC), slag (SL) and Fe-Mn ore (FMO) on immobilization of Pb and Cd through the Toxicity Characteristic Leaching Procedure (TCLP) by following the the European Community Bureau of Reference (BCR), CaCl 2 and NH 4 NO 3 . The sequential extraction of BCR showed decrease in acid soluble fractions, while the residual proportions of Pb and Cd were enhanced with increasing concentrations of SL and BC. Addition of BC significantly lowered the extractable fractions of both metals by TCLP, NH 4 NO 3 and CaCl 2 as compared to SL and FMO. Among all amendments, BC incorporation into co-contaminated soil offered promising results for Pb and Cd immobilization. Overall, all amendments showed positive and long-term impact on the reclamation of co-contaminated soil with heavy metals and could deserve advance monitoring studies on a field scale.
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Sun, Yuebing; Sun, Guohong; Xu, Yingming; Wang, Lin; Lin, Dasong; Liang, Xuefeng; Shi, Xin
2012-01-01
The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd (toxicity characteristic leaching procedure-Cd) concentration, and spinach (Spinacia oleracea) growth and Cd uptake and accumulation were investigated. Results showed that the addition of sepiolite could increase soil pH, while the TCLP-Cd concentration in soil was decreased with increasing sepiolite. The changes of soil enzyme activities and bacteria number indicated that a certain metabolic recovery occurred after the sepiolite treatments, and spinach shoot biomass increased by 58.5%-65.5% in comparison with the control group when the concentration of sepiolite was < or = 10 g/kg. However, the Cd concentrations in the shoots and roots of spinach decreased with an increase in the rate of sepiolite, experiencing 38.4%-59.1% and 12.6%-43.6% reduction, respectively, in contrast to the control. The results indicated that sepiolite has the potential for success on a field scale in reducing Cd entry into the food chain.
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Carbon bed mercury emissions control for mixed waste treatment.
Soelberg, Nick; Enneking, Joe
2010-11-01
Mercury has various uses in nuclear fuel reprocessing and other nuclear processes, and so it is often present in radioactive and mixed (radioactive and hazardous) wastes. Compliance with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include (1) the depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests; (2) MERSORB carbon can sorb mercury up to 19 wt % of the carbon mass; and (3) the spent carbon retained almost all (98.3-99.99%) of the mercury during Toxicity Characteristic Leachability Procedure (TCLP) tests, but when even a small fraction of the total mercury dissolves, the spent carbon can fail the TCLP test when the spent carbon contains high mercury concentrations.
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Reinecke, Adriaan J; van Wyk, Mia; Reinecke, Sophie A
2016-06-01
We determined the toxicity of oil refinery waste in three soils using the springtail Folsomia candida (Collembola) in bioassays. Sublethal exposure to a concentration series of API-sludge presented EC50's for reproduction of 210 mg/kg in site soil; 880 mg/kg in LUFA2.2- and 3260 mg/kg in OECD-soil. The sludge was the least toxic in the OECD-soil with the highest clay and organic matter content, the highest maximum water holding capacity, and the least amount of sand. It was the most toxic in the reference site soil with the lowest organic matter content and highest sand content. The results emphasized the important role of soil characteristics such as texture and organic matter content in influencing toxicity, possibly by affecting bioavailability of toxicants.
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This Scientific Advisory Panel meeting will address selected scientific issues associated with assessing the potential ecological risks resulting from use of a pesticide active ingredient which has persistent, bioaccumulative, and toxic (PBT) characteristics. EPA will pose speci...
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Wei, Ming-Li; Du, Yan-Jun; Reddy, Krishna R; Wu, Hao-Liang
2015-12-01
For viable and sustainable reuse of solidified/stabilized heavy metal-contaminated soils as roadway subgrade materials, long-term durability of these soils should be ensured. A new binder, KMP, has been developed for solidifying/stabilizing soils contaminated with high concentrations of heavy metals. However, the effects of long-term extreme weather conditions including freeze and thaw on the leachability and strength of the KMP stabilized contaminated soils have not been investigated. This study presents a systematic investigation on the impacts of freeze-thaw cycle on leachability, strength, and microstructural characteristics of the KMP stabilized soils spiked with Zn and Pb individually and together. For comparison purpose, Portland cement is also tested as a conventional binder. Several series of tests are conducted including the toxicity characteristic leaching procedure (TCLP), modified European Community Bureau of Reference (BCR) sequential extraction procedure, unconfined compression test (UCT), and mercury intrusion porosimetry (MIP). The results demonstrate that the freeze-thaw cycles have much less impact on the leachability and strength of the KMP stabilized soils as compared to the PC stabilized soils. After the freeze-thaw cycle tests, the KMP stabilized soils display much lower leachability, mass loss, and strength loss. These results are assessed based on the chemical speciation of Zn and Pb, and pore size distribution of the soils. Overall, this study demonstrates that the KMP stabilized heavy metal-contaminated soils perform well under the freeze-thaw conditions.
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Jelusic, Masa; Lestan, Domen
2014-03-15
We applied a multi-level approach assessing the quality, toxicity and functioning of Pb, Zn and Cd contaminated/remediated soil from a vegetable garden in Meza Valley, Slovenia. Contaminated soil was extracted with EDTA and placed into field experimental plots equipped with lysimeters. Soil properties were assessed by standard pedological analysis. Fractionation and leachability of toxic metals were analyzed by sequential extraction and TCLP and metal bioaccessibility by UBM tests. Soil respiration and enzyme activities were measured as indicators of soil functioning. Remediation reduced the metal burden by 80, 28 and 72% for Pb, Zn and Cd respectively, with a limited impact on soil pedology. Toxic metals associated with labile soil fractions were largely removed. No shifts between labile and residual fractions were observed during the seven months of the experiment. Initial metal leaching measured through lysimeters eventually ceased. However, remediation significantly diminished potential soil enzyme activity and no trends were observed of the remediated soil recovering its biological properties. Soil washing successfully removed available forms of Pb, Zn and Cd and thus lowered the human and environmental hazards of the remediated soil; however, remediation also extracted the trace elements essential for soil biota. In addition to reduced water holding capacity, soil health was not completely restored. Copyright © 2013 Elsevier B.V. All rights reserved.
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Aroch, Itamar; Klement, Eyal; Segev, Gilad
2005-01-01
Neutrophil cytoplasmic toxicity is manifested as an abnormality in cell size or the cytoplasmic content upon examination of Romanowsky-stained blood smears, and is traditionally associated with infection and inflammation. The purpose of this retrospective study was to investigate the association of such changes with clinical and clinicopathologic characteristics, diseases, and prognoses in dogs. Dogs with neutrophil toxicity (n = 248) were compared with negative controls (n = 248). Statistical analyses included chi-square tests, independent t-tests, nonparametric Mann-Whitney tests, the chi-square trend test, and survival analysis. Dogs with neutrophil toxicity had a significantly higher prevalence of pale mucous membranes, tachycardia, fever, abdominal organomegaly, icterus, melena, and hematuria. Most mean hematologic variables were significantly different between groups. Dogs with neutrophil toxicity had a significantly (P < .05) higher prevalence of leukocytosis, leukopenia, neutrophilia, neutropenia, anemia, hyponatremia, hypokalemia, hypoproteinemia, hypoalbuminemia, and hypocalcemia. The prevalence of pyometra, parvovirus infection, acute renal failure, peritonitis, immune-mediated hemolytic anemia, disseminated intravascular coagulation, pancreatitis, septicemia, and neoplastic disorders was significantly higher among these dogs. Case fatality, hospitalization length, and treatment cost were significantly (P < .001) higher in dogs with neutrophil toxicity. Neutrophil toxicity severity was significantly (P < .0035) and positively associated with neutropenia, and negatively associated with leukocytosis and neutrophilia. A significant trend (P = .05) toward increasing case fatality with an increase of neutrophil toxicity was observed. In the neutrophil toxicity group, dogs with leukopenia (<5.0 X 10(3)/mm3) had a significantly (P < .0001) higher case fatality compared to dogs with normal or high leukocyte counts. We conclude that evaluation of blood smears for
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Diaz-Loya, E Ivan; Allouche, Erez N; Eklund, Sven; Joshi, Anupam R; Kupwade-Patil, Kunal
2012-08-01
Municipal solid waste (MSW) incineration is a common and effective practice to reduce the volume of solid waste in urban areas. However, the byproduct of this process is a fly ash (IFA), which contains large quantities of toxic contaminants. The purpose of this research study was to analyze the chemical, physical and mechanical behaviors resulting from the gradual introduction of IFA to an alkaline activated coal fly ash (CFA) matrix, as a mean of stabilizing the incinerator ash for use in industrial construction applications, where human exposure potential is limited. IFA and CFA were analyzed via X-ray fluorescence (XRF), X-ray diffraction (XRD) and Inductive coupled plasma (ICP) to obtain a full chemical analysis of the samples, its crystallographic characteristics and a detailed count of the eight heavy metals contemplated in US Title 40 of the Code of Federal Regulations (40 CFR). The particle size distribution of IFA and CFA was also recorded. EPA's Toxicity Characteristic Leaching Procedure (TCLP) was followed to monitor the leachability of the contaminants before and after the activation. Also images obtained via Scanning Electron Microscopy (SEM), before and after the activation, are presented. Concrete made from IFA, CFA and IFA-CFA mixes was subjected to a full mechanical characterization; tests include compressive strength, flexural strength, elastic modulus, Poisson's ratio and setting time. The leachable heavy metal contents (except for Se) were below the maximum allowable limits and in many cases even below the reporting limit. The leachable Chromium was reduced from 0.153 down to 0.0045 mg/L, Arsenic from 0.256 down to 0.132 mg/L, Selenium from 1.05 down to 0.29 mg/L, Silver from 0.011 down to .001 mg/L, Barium from 2.06 down to 0.314 mg/L and Mercury from 0.007 down to 0.001 mg/L. Although the leachable Cd exhibited an increase from 0.49 up to 0.805 mg/L and Pd from 0.002 up to 0.029 mg/L, these were well below the maximum limits of 1.00 and 5
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Speciation analysis and leaching behaviors of selected trace elements in spent SCR catalyst.
Dai, Zejun; Wang, Lele; Tang, Hao; Sun, Zhijun; Liu, Wei; Sun, Yi; Su, Sheng; Hu, Song; Wang, Yi; Xu, Kai; Liu, Liang; Ling, Peng; Xiang, Jun
2018-09-01
This study investigated heavy metal chemical speciation and leaching behavior from a board-type spent selective catalytic reduction (SCR) catalyst containing high concentrations of vanadium, chromium, nickel, copper, zinc, and lead. A three-step sequential extraction method, standard toxicity characteristic leaching procedure (TCLP), and leaching characteristic tests have been performed. It was found that the mobility of six heavy metals in the spent SCR catalyst was significantly different. The mobility of the six heavy metals exhibited the following order: Ni > Zn > V > Cr > As > Cu. Meanwhile, TCLP test results revealed relatively high Zn and Cr leaching rate of 83.20% and 10.35%, respectively. It was found that leaching rate was positively correlated with available contents (sum of acid soluble, reducible and oxidizable fractions). Leaching characteristics tests indicated that pH substantially affected the leaching of these heavy metals. In particular, the leaching of Cr, Ni, Cu, and Zn was positively influenced by strong acid, while V and As were easily released in the presence of strong acid and strong alkali (pH < 3 or pH > 11). In terms of kinetics, the leaching of Cr, Ni, Cu, Zn, and As within the spent catalyst was dominated by erosion and dissolution processes, which were rapid reaction processes. V was released in large amounts within 1 h, but its leaching amount sharply decreased with time due to readsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Immobilization of copper flotation waste using red mud and clinoptilolite.
Coruh, Semra
2008-10-01
The flash smelting process has been used in the copper industry for a number of years and has replaced most of the reverberatory applications, known as conventional copper smelting processes. Copper smelters produce large amounts of copper slag or copper flotation waste and the dumping of these quantities of copper slag causes economic, environmental and space problems. The aim of this study was to perform a laboratory investigation to assess the feasibility of immobilizing the heavy metals contained in copper flotation waste. For this purpose, samples of copper flotation waste were immobilized with relatively small proportions of red mud and large proportions of clinoptilolite. The results of laboratory leaching demonstrate that addition of red mud and clinoptilolite to the copper flotation waste drastically reduced the heavy metal content in the effluent and the red mud performed better than clinoptilolite. This study also compared the leaching behaviour of metals in copper flotation waste by short-time extraction tests such as the toxicity characteristic leaching procedure (TCLP), deionized water (DI) and field leach test (FLT). The results of leach tests showed that the results of the FLT and DI methods were close and generally lower than those of the TCLP methods.
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Uranium content and leachable fraction of fluorspars
Landa, E.R.; Councell, T.B.
2000-01-01
Much attention in the radiological health community has recently focused on the management and regulation of naturally occurring radioactive materials. Although uranium-bearing minerals are present in a variety of fluorspar deposits, their potential consideration as naturally occurring radioactive materials has received only limited recognition. The uranium content of 28 samples of acid- and cryolite-grade (>97% CaF2) fluorspar from the National Defense Stockpile was found to range from 120 to 24,200 ??g kg-1, with a mean of 2,145 ??g kg-1. As a point of comparison, the average concentration of uranium in the upper crust of the earth is about 2,500 ??g kg-1. Leachability of this uranium was assessed by means of the Toxicity Characteristic Leaching Procedure (TCLP). The TCLP extractable fraction ranged from 1 to 98%, with a mean of 24% of the total uranium. The typically low concentrations of uranium seen in these materials probably reflects the removal of uranium-bearing mineral phases during the beneficiation of the crude fluorspar ore to achieve industrial specifications. Future NORM studies should examine crude fluorspar ores and flotation tailings.
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Integrated copper-containing wastewater treatment using xanthate process.
Chang, Yi-Kuo; Chang, Juu-En; Lin, Tzong-Tzeng; Hsu, Yu-Ming
2002-09-02
Although, the xanthate process has been shown to be an effective method for heavy metal removal from contaminated water, a heavy metal contaminated residual sludge is produced by the treatment process and the metal-xanthate sludge must be handled in accordance with the Taiwan EPA's waste disposal requirements. This work employed potassium ethyl xanthate (KEX) to remove copper ions from wastewater. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) were used to determine the leaching potential and stability characteristics of the residual copper xanthate (Cu-EX) complexes. Results from metal removal experiments showed that KEX was suitable for the treatment of copper-containing wastewater over a wide copper concentration range (50, 100, 500, and 1000 mg/l) to the level that meets the Taiwan EPA's effluent regulations (3mg/l). The TCLP results of the residual Cu-EX complexes could meet the current regulations and thus the Cu-EX complexes could be treated as a non-hazardous material. Besides, the results of SDLT indicated that the complexes exhibited an excellent performance for stabilizing metals under acidic conditions, even slight chemical changes of the complexes occurred during extraction. The xanthate process, mixing KEX with copper-bearing solution to form Cu-EX precipitates, offered a comprehensive strategy for solving both copper-containing wastewater problems and subsequent sludge disposal requirements.
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Jagupilla, Santhi C; Wazne, Mahmoud; Moon, Deok Hyun
2015-10-01
Chromite Ore Processing Residue (COPR) is an industrial waste containing up to 7% chromium (Cr) including up to 5% hexavalent chromium [Cr(VI)]. The remediation of COPR has been challenging due to the slow release of Cr(VI) from a clinker like material and thereby the incomplete detoxification of Cr(VI) by chemical reagents. The use of sulfur based reagents such as ferrous sulfate and calcium polysulfide to detoxify Cr(VI) has exasperated the swell potential of COPR upon treatment. This study investigated the use of ferrous chloride alone and in combination with Portland cement to address the detoxification of Cr(VI) in COPR and the potential swell of COPR. Chromium regulatory tests, X-ray powder diffraction (XRPD) analyses and X-ray absorption near edge structure (XANES) analyses were used to assess the treatment results. The treatment results indicated that Cr(VI) concentrations for the acid pretreated micronized COPR as measured by XANES analyses were below the New Jersey Department of Environmental Protection (NJDEP) standard of 20 mg kg(-1). The Toxicity characteristic leaching procedure (TCLP) Cr concentrations for all acid pretreated samples also were reduced below the TCLP regulatory limit of 5 mg L(-1). Moreover, the TCLP Cr concentration for the acid pretreated COPR with particle size ⩽0.010 mm were less than the universal treatment standard (UTS) of 0.6 mg L(-1). The treatment appears to have destabilized all COPR potential swell causing minerals. The unconfined compressive strength (UCS) for the treated samples increased significantly upon treatment with Portland cement. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Leaching potential of silver from nanosilver-treated textile products.
Limpiteeprakan, P; Babel, S
2016-03-01
The use of nanosilver as an antibacterial agent for various products has increased, especially so, in textiles. This study aims to investigate the potential of Ag to leach from commercial products which contain nano-Ag by using the toxicity characteristic leaching procedure (TCLP) test in accordance with USEPA method 1311. Eight nano-Ag products were purchased from the market. Only those products that are likely to be disposed of in a landfill after end use were selected. Nano-Ag fabrics of different concentrations were also prepared at the laboratory scale, and the TCLP test was performed on them as well. The current study assumes that the new products were discarded without use. The Ag content was quantified by inductively coupled plasma-mass spectroscopy (ICP-MS) and ranged from 0.95 to 2.82 μg/g of the product in the commercial products and from 1.49 to 350 μg/g of the product in the lab-prepared fabrics. In the TCLP test results, Ag concentrations ranged from 4.3 to 64.9 μg/L in the commercial products and from 28.9 to 28,381 μg/L in the lab-prepared fabrics. The results also indicate that the amount of Ag released depends on the type of the fabrics. Additionally, the size of the nano-Ag released in percentage is different for each prepared fabric. This study can help in understanding the amount of Ag released during the disposal phase of a product in a landfill.
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Newman, M C; McCloskey, J T; Tatara, C P
1998-01-01
Ecological risk assessment can be enhanced with predictive models for metal toxicity. Modelings of published data were done under the simplifying assumption that intermetal trends in toxicity reflect relative metal-ligand complex stabilities. This idea has been invoked successfully since 1904 but has yet to be applied widely in quantitative ecotoxicology. Intermetal trends in toxicity were successfully modeled with ion characteristics reflecting metal binding to ligands for a wide range of effects. Most models were useful for predictive purposes based on an F-ratio criterion and cross-validation, but anomalous predictions did occur if speciation was ignored. In general, models for metals with the same valence (i.e., divalent metals) were better than those combining mono-, di-, and trivalent metals. The softness parameter (sigma p) and the absolute value of the log of the first hydrolysis constant ([symbol: see text] log KOH [symbol: see text]) were especially useful in model construction. Also, delta E0 contributed substantially to several of the two-variable models. In contrast, quantitative attempts to predict metal interactions in binary mixtures based on metal-ligand complex stabilities were not successful. PMID:9860900
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Yang, Wen-Tao; Wang, Ying-Jie; Zhou, Hang; Yi, Kai-Xin; Zeng, Min; Peng, Pei-Qin; Liao, Bo-Han
2015-02-01
Speciation and bioavailability of arsenic in the rhizosphere and non-rhizosphere soils at different growth stages (tillering stage, jointing stage, booting stage, filling stage and maturing stage) of rice (Oryza sativa L.) were studied using toxicity characteristic leaching procedure (TCLP) and arsenic speciation analysis. Pot experiments were conducted and the soil samples were taken from a certain paddy soil in Hunan Province contaminated by mining industry. The results showed that: (1) With the extension of rice growth period, pH values and TCLP extractable arsenic levels in the rhizosphere and non-rhizosphere soils increased gradually. Soil pH and TCLP extractable arsenic levels in non-rhizosphere soils were higher than those in the rhizosphere soils at the same growth stage. (2) At the different growth stages of rice, contents of exchangeable arsenic (AE-As) in rhizosphere and non-rhizosphere soils were lower than those before the rice planting, and increased gradually with the extension of the rice growing period. Contents of Al-bound arsenic (Al-As), Fe-bound arsenic (Fe-As) and Ca-bound arsenic (Ca-As) increased gradually after rice planting, but not significantly. Residual arsenic (O-As) and total arsenic (T-As) decreased gradually after rice planting, by 37.30% and 14.69% in the rhizosphere soils and by 31.38% and 8.67% in the non-rhizosphere soils, respectively. (3) At the different growth stages of rice, contents of various forms of arsenic in the soils were in the following order: residual arsenic (O-As) > Fe-bound arsenic ( Fe-As) > Al-bound arsenic (Al-As) > Ca-bound arsenic (Ca-As) > exchangeable arsenic (AE-As). In the pH range of 5.0- 5.8, significant positive linear correlations were found between most forms of arsenic or TCLP extractable arsenic levels and pH values, while the Ca-bound arsenic was poorly correlated with pH values in the rhizosphere soils.
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Electrical Insulation Fire Characteristics : Volume 2. Toxicity.
DOT National Transportation Integrated Search
1978-12-01
The purpose of this research was to determine the relative inhalation toxicity of the thermal degradation products or gaseous pyrolysis of selected types of electrical wiring insulations. The specific materials to be evaluated were supplied by the Bo...
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Environmental risk related to specific processes during scrap computer recycling and disposal.
Li, Jinhui; Shi, Pixing; Shan, Hongshan; Xie, Yijun
2012-12-01
The purpose of this work was to achieve a better understanding of the generation of toxic chemicals related to specific processes in scrap computer recycling and disposal, such as thermal recycling of printed circuit boards (PCBs) and the landfilling or dumping of cathode ray tubes (CRTs). Tube furnace pyrolysis was carried out to simulate different thermal treatment conditions for the identification of the by-products and potential environmental risk from thermal recycling ofPCBs. The Toxicity Characteristic Leaching Procedure (TCLP) and a column test were used to study the leaching characteristics of lead from waste CRT glass, which is one of the most important environmental concerns arising from the disposal of e-waste. The results indicate that more attention should be paid to the benzene series when recycling PCBs under thermal conditions, especially for workers without any personal protection equipment. The impact of immersion on the leaching of lead from CRT leaded glass was more effective than the impact of washing only by acid rain. Thus when waste leaded glass has to be stored for some reason, the storage facility should be dry.
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NASA Astrophysics Data System (ADS)
Cher, S.; Menghua, L.; Xiao, X.; Yuqi, W.; Zhuangmin, Z.; Zhijiong, H.; Cheng, L.; Guanglin, J.; Zibing, Y.; Junyu, Z.
2017-12-01
Atmospheric toxic metals (TMs) are part of particulate matters, and may create adverse effects on the environment and human health depending upon their bioavailability and toxicity. Localized emission inventory is fundamental for parsing of toxic metals to identify key sources in order to formulate efficient toxic metals control strategies. With the use of the latest municipal level environment statistical data, this study developed a bottom-up emission inventory of five toxic metals (Hg, As, Pb, Cd, Cr) from anthropogenic activities in Guangdong province for the year of 2014. Major atmospheric toxic metals sources including combustion sources (coal, oil, biomass, municipal solid waste) and industrial process sources (cement production, nonferrous metal smelting, iron and steel industry, battery and fluorescent lamp production) were investigated. Results showed that: (1) The total emissions of Hg, As, Pb, Cd, Cr in Guangdong province were 18.14, 32.59, 411.34, 13.13, 84.16 t, respectively. (2) Different pollutants have obvious characteristics of emission sources. For total Hg emission, 46% comes from combustion sources, of which 32% from coal combustion and 8% from MSW combustion. Other 54% comes from industrial processes, which dominated by the cement (19%), fluorescent lamp (18%) and battery production (13%). Of the total Hg emission, 69% is released as Hg0 , 29% as Hg2+ , and only 2% as Hgp due to strict particulate matters controls policies. For As emissions, coal combustion, nonferrous metal smelting and iron and steel industry contributed approximate 48%, 25% and 24%, respectively. Pb emissions primarily come from battery production (42%), iron and steel industry (21%) and on-road mobile gasoline combustion (17%). Cd and Cr emissions were dominated by nonferrous metal smelting (71%) and iron and steel industry (82%), respectively. (3) In term of the spatial distribution, emissions of atmospheric toxic metals are mainly concentrated in the central region of
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Toxic substances alert program
NASA Technical Reports Server (NTRS)
Junod, T. L.
1978-01-01
A toxicity profile is provided, of 187 toxic substances procured by NASA Lewis Research Center during a 3 1/2 year period, including 27 known or suspected carcinogens. The goal of the program is to assure that the center's health and safety personnel are aware of the procurement and use of toxic substances and to alert and inform the users of these materials as to the toxic characteristics and the control measures needed to ensure their safe use. The program also provides a continuing record of the toxic substances procured, who procured them, what other toxic substances the user has obtained in the past, and where similar materials have been used elsewhere at the center.
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Response characteristics of an aquatic biomonitor used for rapid toxicity detection.
van der Schalie, W H; Shedd, T R; Widder, M W; Brennan, L M
2004-01-01
The response characteristics of an aquatic biomonitor that detects toxicity by monitoring changes in bluegill (Lepomis macrochirus Rafinesque) ventilatory and movement patterns were evaluated in single chemical laboratory studies at concentrations near the 96-h LC(50) concentration and at the EILATox-Oregon Workshop in sequential tests of multiple unknown samples. Baseline data collected prior to exposure allows each fish to serve as its own control. When at least 70% of exposed fish exhibit ventilatory or movement parameters significantly different from baseline observations, a group alarm is declared. In the laboratory studies, the aquatic biomonitor responded to the majority of chemicals at the 96-h lc(50) within an hour or less, although substantially higher response times were found for malathion and pentachlorophenol. Workshop tests of single chemical concentrations presented as blind samples were consistent with the laboratory test results. There were no alarms under control conditions in any test. Although data are limited, the aquatic biomonitor appears to respond more rapidly to chemicals causing membrane irritation, narcosis or polar narcosis than to acetylcholinesterase inhibitors or oxidative phosphorylation uncouplers. All four monitored parameters (ventilatory rate, cough rate, ventilatory depth and movement) contributed to identification of first alarms at acutely toxic levels. Understanding these response patterns can be useful in data interpretation for biomonitor applications such as surface water monitoring for watershed protection, wastewater treatment plant effluent monitoring or source water monitoring for drinking water protection. Copyright (c) 2004 John Wiley & Sons, Ltd.
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Extends the compliance date of the Toxicity Characteristic until January 25, 1991 for groundwater that is reinjected or reinfiltrated during existing hydrocarbon recovery operations at petroleum refineries, marketing terminals, and bulk plants.
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Huang, Guoyong; Su, Xiaojuan; Rizwan, Muhammad Shahid; Zhu, Yifei; Hu, Hongqing
2016-08-01
Soil contamination with toxic metals has increasingly become a global concern over the past few decades. Phosphate and carbonate compounds are good passivation materials for Pb immobilization, while the effect of phosphate and carbonate on the immobilization of multiple heavy metals (Pb, Cu, and Cd) in contaminated soils was seldom investigated. In this study, bone meal (BM), phosphate rock (PR), oxalic acid-activated phosphate rock (APR), super phosphate (SP), and calcium carbonate (CC) were added to the contaminated soils to evaluate the effect of phosphate materials and calcium carbonate on the immobilization of Pb, Cu, and Cd. The results showed that the pH of the treated soils increased 1.3-2.7, except SP which decreased 0.5 at most. Compared to the control treatment, all phosphates and calcium carbonate added to the polluted soils increased the fraction of residual metals, and the application of APR, PR, BM, and CC significantly reduced exchangeable and carbonate-bound fraction metals. PR and APR were the most effective for the immobilization of Pb, Cu, and Cd in the soils among these materials. Moreover, the concentrations of all metals in the toxicity characteristic leaching procedure (TCLP) leachate decreased with increasing amounts of amendments, and the concentrations of Pb in the TCLP leachate for soils treated with PR and APR were below the nonhazardous regulatory limit of 5 mg L(-1) (US Environmental Protection Agency). Based on our results, phosphate rock and oxalic acid-activated phosphate rock are effective in the immobilization of multiple metals by reducing their mobility in the co-contaminated soils.
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Non-combustible waste vitrification with plasma torch melter.
Park, J K; Moon, Y P; Park, B C; Song, M J; Ko, K S; Cho, J M
2001-05-01
Non-combustible radioactive wastes generated from Nuclear Power Plants (NPPs) are composed of concrete, glass, asbestos, metal, sand, soil, spent filters, etc. The melting tests for concrete, glass, sand, and spent filters were carried out using a 60 kW plasma torch system. The surrogate wastes were prepared for the tests. Non-radioactive Co and Cs were added to the surrogates in order to simulate the radioactive waste. Several kinds of surrogate prepared by their own mixture or by single waste were melted with the plasma torch system to produce glassy waste forms. The characteristics of glassy waste forms were examined for the volume reduction factor (VRF) and the leach rate. The VRFs were estimated through the density measurement of the surrogates and the glassy waste forms, and were turned out to be 1.2-2.4. The EPA (Environmental Protection Agency) Toxicity Characteristic Leaching Procedure (TCLP) was used to determine the leach resistance for As, Ba, Hg, Pb, Cd, Cr, Se, Co, and Cs. The leaching index was calculated using the total content of each element in both the waste forms and the leachant. The TCLP tests resulted in that the leach rates for all elements except Co and Cs were lower than those of the Universal Treatment Standard (UTS) limits. There were no UTS limits for Co and Cs, and their leach rate & index from the experiments were resulted in around 10 times higher than those of other elements.
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Proposal to extend the compliance date for the Toxicity Characteristic until January 25, 1993 for produced groundwater from free phase hydrocarbon recovery operations at certain petroleum industry sites-namely, refineries, marketing terminals, bulk plants.
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Wang, Li; Li, Yong-Hua; Ji, Yan-Fang; Yang, Lin-Sheng; Li, Hai-Rong; Zhang, Xiu-Wu; Yu, Jiang-Ping
2011-07-01
The composite agents containing potassium chloride (KCl) and Hydroxyapatite (HA) were used to remediate the lead and cadmium contaminated soil in Fenghuang lead-zinc mining-smelting areas, Hunan province. The objective of this study was to identify and evaluate the influence of Cl- to the fixing efficiency of Pb and Cd by HA. Two types of contaminated soil (HF-1, HF-2) were chosen and forty treatments were set by five different Hydroxyapatite (HA) dosages and four different Cl- dosages. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the results. It showed that HA could efficiently fix the Pb and Cd from TCLP form. The maximum Pb-fixing efficiency and Cd-fixing efficiency of two types of soil were 83.3%, 97.27% and 35.96%, 57.82% when the HA: Pb: KCl molar ratio was 8: 1: 2. Compared to the fixing efficiency without KCl, KCl at the KCl: Pb molar ratio of 2 improved Pb-fixing efficiency and Cd-fixing efficiency by 6.26%, 0.33% and 7.74%, 0.83% respectively when the HA: Pb molar ratio was 8. Generally, Cl- can improve the Pb/Cd-fixing efficiency in heavy metal contaminated soil by Hydroxyapatite.
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A combined evaluation of the characteristics and acute toxicity of antibiotic wastewater.
Yu, Xin; Zuo, Jiane; Li, Ruixia; Gan, Lili; Li, Zaixing; Zhang, Fei
2014-08-01
The conventional parameters and acute toxicities of antibiotic wastewater collected from each treatment unit of an antibiotic wastewater treatment plant have been investigated. The investigation of the conventional parameters indicated that the antibiotic wastewater treatment plant performed well under the significant fluctuation in influent water quality. The results of acute toxicity indicated that the toxicity of antibiotic wastewater could be reduced by 94.3 percent on average after treatment. However, treated antibiotic effluents were still toxic to Vibrio fischeri. The toxicity of antibiotic production wastewater could be attributed to the joint effects of toxic compound mixtures in wastewater. Moreover, aerobic biological treatment processes, including sequencing batch reactor (SBR) and aerobic biofilm reactor, played the most important role in reducing toxicity by 92.4 percent. Pearson׳s correlation coefficients revealed that toxicity had a strong and positive linear correlation with organic substances, nitrogenous compounds, S(2-), volatile phenol, cyanide, As, Zn, Cd, Ni and Fe. Ammonia nitrogen (NH4(+)) was the greatest contributor to toxicity according to the stepwise regression method. The multiple regression model was a good fit for [TU50-15 min] as a function of [NH₄(+)] with the determination coefficient of 0.981. Copyright © 2014 Elsevier Inc. All rights reserved.
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Xue, Mianqiang; Zhou, Liang; Kojima, Naoya; Dos Muchangos, Leticia Sarmento; Machimura, Takashi; Tokai, Akihiro
2018-05-01
Increasing manufacture and usage of chemicals have not been matched by the increase in our understanding of their risks. Pollutant release and transfer register (PRTR) is becoming a popular measure for collecting chemical data and enhancing the public right to know. However, these data are usually in high dimensionality which restricts their wider use. The present study partitions Japanese PRTR chemicals into five fuzzy clusters by fuzzy c-mean clustering (FCM) to explore the implicit information. Each chemical with membership degrees belongs to each cluster. Cluster I features high releases from non-listed industries and the household sector and high environmental toxicity. Cluster II is characterized by high reported releases and transfers from 24 listed industries above the threshold, mutagenicity, and high environmental toxicity. Chemicals in cluster III have characteristics of high releases from non-listed industries and low toxicity. Cluster IV is characterized by high reported releases and transfers from 24 listed industries above the threshold and extremely high environmental toxicity. Cluster V is characterized by low releases yet mutagenicity and high carcinogenicity. Chemicals with the highest membership degree were identified as representatives for each cluster. For the highest membership degree, half of the chemicals have a value higher than 0.74. If we look at both the highest and the second highest membership degrees simultaneously, about 94% of the chemicals have a value higher than 0.5. FCM can serve as an approach to uncover the implicit information of highly complex chemical dataset, which subsequently supports the strategy development for efficient and effective chemical management. Copyright © 2017 Elsevier B.V. All rights reserved.
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The Agency is promulgating an interim final rule to extend the compliance date of the Toxicity Characteristic rule for petroleum refining facilities, marketing terminals and bulk plants engaged in the recovery and remediation operation for 120 days.
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Application of Toxic Chinese Medicine in Chinese Pharmacopoeia
NASA Astrophysics Data System (ADS)
Zhao, Hui; Feng, Yu; Mao, Mingsan
2018-01-01
Objective: Explore the application characteristics of proprietary Chinese medicine prescriptions containing toxic herbs in pharmacopoeia. Methods: In this paper, according to the clinical application of pharmacopoeia proprietary Chinese medicine is divided into table agent, Qushu agent, diarrhea agent, heat agent, Wen Li agent, cough and asthma agents, resuscitation agent, Gutian agent, Fuzheng agent, Anshen agent, hemostatic agent, The traditional Chinese medicine prescription and the clinical application of the Chinese herbal medicine containing the toxic Chinese medicine were analyzed and sorted out., Summed up the compatibility of toxic herbs and application characteristics. Results: Toxic Chinese herbal medicine in the cure of traditional Chinese medicine to play a long-standing role, through the overall thinking, dialectical thinking, and thinking of toxic Chinese medicine in the analysis of Chinese medicine that [2], toxic Chinese medicine in the application of proprietary Chinese medicine can not lack. Conclusion: Pharmacopoeia included proprietary Chinese medicine not only in the clinical treatment of good, but also the application of its toxic traditional Chinese medicine and its understanding of the enrichment of the toxic characteristics of traditional Chinese medicine and treatment-related disease pathology between the points of contact for patients with clinical applications Based on and theoretical guidance of Chinese medicine [3].
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Development of Ecological Toxicity and Biomagnification Data for Explosives Contaminants in Soil
2003-07-01
explosive contaminated soil leachates to Daphnia magna using an adapted toxicity characteristic leaching procedure. U.S. Army Chemical and Biological...1993) Toxicity determination of explosive contaminated soil leachates to Daphnia magna using an adapted toxicity characteristic leaching procedure...Sadusky, M. (1993). Toxicity determination of explosive contaminated soil leachates to Daphnia magna using C-46 an adapted toxicity
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Smith, S; Lizotte, R E
2007-11-01
This study was conducted to assess the influence of suspended solids, dissolved organic carbon, and phytoplankton (as chlorophyll a) water quality characteristics on lambda-cyhalothrin and gamma-cyhalothrin aqueous toxicity to Hyalella azteca using natural water from 12 ponds and lakes in Mississippi, USA with varying water quality characteristics. H. azteca 48-h immobilization EC50 values ranged from 1.4 to 15.7 ng/L and 0.6 to 13.4 ng/L for lambda-cyhalothrin and gamma-cyhalothrin, respectively. For both pyrethroids, EC50 values linearly increased as turbidity, suspended solids, dissolved organic carbon and chlorophyll a concentrations increased.
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Besser, J.M.; Brumbaugh, W.G.; Kemble, N.E.; May, T.W.; Ingersoll, C.G.
2004-01-01
We evaluated the influence of sediment characteristics, acid-volatile sulfide (AVS) and organic matter (OM), on the toxicity of chromium (Cr) in freshwater sediments. We conducted chronic (28-42-d) toxicity tests with the amphipod Hyalella azteca exposed to Cr(VI) and Cr(III) in water and in spiked sediments. Waterborne Cr(VI) caused reduced survival of amphipods with a median lethal concentration (LC50) of 40 ??g/L. Cr(VI) spiked into test sediments with differing levels of AVS resulted in graded decreases in AVS and sediment OM. Only Cr(VI)-spiked sediments with low AVS concentrations (<1 ??mol/g) caused significant amphipod mortality. Waterborne Cr(III) concentrations near solubility limits caused decreased survival of amphipods at pH 7 and pH 8 but not at pH 6. Sediments spiked with high levels of Cr(III) did not affect amphipod survival but had minor effects on growth and inconsistent effects on reproduction. Pore waters of some Cr(III)-spiked sediments contained measurable concentrations of Cr(VI), but observed toxic effects did not correspond closely to Cr concentrations in sediment or pore waters. Our results indicate that risks of Cr toxicity are low in freshwater sediments containing substantial concentrations of AVS.
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Toxic Leadership in Educational Organizations
ERIC Educational Resources Information Center
Green, James E.
2014-01-01
While research on the traits and skills of effective leaders is plentiful, only recently has the phenomenon of toxic leadership begun to be investigated. This research report focuses on toxic leadership in educational organizations--its prevalence, as well as the characteristics and early indicators. Using mixed methods, the study found four…
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40 CFR 798.4900 - Developmental toxicity study.
Code of Federal Regulations, 2011 CFR
2011-07-01
... study is designed to provide information on the potential hazard to the unborn which may arise from... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Developmental toxicity study. 798.4900... Developmental toxicity study. (a) Purpose. In the assessment and evaluation of the toxic characteristics of a...
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40 CFR 798.4900 - Developmental toxicity study.
Code of Federal Regulations, 2012 CFR
2012-07-01
... study is designed to provide information on the potential hazard to the unborn which may arise from... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Developmental toxicity study. 798.4900... Developmental toxicity study. (a) Purpose. In the assessment and evaluation of the toxic characteristics of a...
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40 CFR 798.4900 - Developmental toxicity study.
Code of Federal Regulations, 2013 CFR
2013-07-01
... study is designed to provide information on the potential hazard to the unborn which may arise from... 40 Protection of Environment 33 2013-07-01 2013-07-01 false Developmental toxicity study. 798.4900... Developmental toxicity study. (a) Purpose. In the assessment and evaluation of the toxic characteristics of a...
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40 CFR 798.4900 - Developmental toxicity study.
Code of Federal Regulations, 2014 CFR
2014-07-01
... study is designed to provide information on the potential hazard to the unborn which may arise from... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Developmental toxicity study. 798.4900... Developmental toxicity study. (a) Purpose. In the assessment and evaluation of the toxic characteristics of a...
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Zuo, Ji-Chao; Gao, Ting-Ting; Su, Xiao-Juan; Wan, Tian-Ying; Hu, Hong-Qing
2014-10-01
Organic acids can improve the phosphorus availability, influence the immobilization of heavy metals in soil, and has very complicated function in phosphorus activation and heavy metal passivation. This research took simulated Pb contaminated soil as material, phosphate and citric acid as remediation matter, adopted BCR continuous extraction, 0.01 mol · L(-1) CaCl2 and toxicity characteristic leaching procedure (TCLP) to evaluate the remediation effect. Besides, malic acid and NaNO3 were taken as desorption reagents to discuss the stability of the phosphorus-citric acid-Pb system. The results showed that: in the absence of citric acid, the amount of acid extracted Pb decreased along with the increase of P concentration; when the P concentration was 100 and 400 mg · kg(-1), acid extractable Pb increased with the increasing of citric acid concentration. However, residual Pb changed in the opposite direction from acid extractable Pb. The phenomenon showed that P improved the bioavailability of Pb, while citric acid had the opposite effect. With a certain organic acid concentration, extractable Pb contents extracted by 0.01 mol · L(-1) CaCl2 and TCLP both decreased with the increasing P concentration, therefore, P had immobilization effect on Pb in contaminated soil. But at a fixed P concentration, extractable Pb contents by 0.01 mol · L(-1) CaCl2 and TCLP changed in the opposite trend with the increasing citric acid concentration. The desorption rate of Pb in soil increased with the increasing malic acid concentration, the decreasing pH and the increasing ionic strength. The desorption extent of Pb in soil with P only was lower than that with both P and citric acid. But the stability of Pb passivated by the former was higher.
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Chemical and physical properties of dry flue gas desulfurization products.
Kost, David A; Bigham, Jerry M; Stehouwer, Richard C; Beeghly, Joel H; Fowler, Randy; Traina, Samuel J; Wolfe, William E; Dick, Warren A
2005-01-01
Beneficial and environmentally safe recycling of flue gas desulfurization (FGD) products requires detailed knowledge of their chemical and physical properties. We analyzed 59 dry FGD samples collected from 13 locations representing four major FGD scrubbing technologies. The chemistry of all samples was dominated by Ca, S, Al, Fe, and Si and strong preferential partitioning into the acid insoluble residue (i.e., coal ash residue) was observed for Al, Ba, Be, Cr, Fe, Li, K, Pb, Si, and V. Sulfur, Ca, and Mg occurred primarily in water- or acid-soluble forms associated with the sorbents or scrubber reaction products. Deionized water leachates (American Society for Testing and Materials [ASTM] method) and dilute acetic acid leachates (toxicity characteristic leaching procedure [TCLP] method) had mean pH values of >11.2 and high mean concentrations of S primarily as SO(2-)4 and Ca. Concentrations of Ag, As, Ba, Cd, Cr, Hg, Pb, and Se (except for ASTM Se in two samples) were below drinking water standards in both ASTM and TCLP leachates. Total toxicity equivalents (TEQ) of dioxins, for two FGD products used for mine reclamation, were 0.48 and 0.53 ng kg(-1). This was similar to the background level of the mine spoil (0.57 ng kg(-1)). The FGD materials were mostly uniform in particle size. Specific surface area (m2 g(-1)) was related to particle size and varied from 1.3 for bed ash to 9.5 for spray dryer material. Many of the chemical and physical properties of these FGD samples were associated with the quality of the coal rather than the combustion and SO2 scrubbing processes used.
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Recovery of valuable metals from electroplating sludge with reducing additives via vitrification.
Huang, Ruth; Huang, Kuo-Lin; Lin, Zih-Yi; Wang, Jian-Wen; Lin, Chitsan; Kuo, Yi-Ming
2013-11-15
In this study, vitrification was applied to treat Ni-Cu electroplating sludge. The sludge was mixed with additives (limestone:cullet = 4:6) and then heated to 1450 °C. The cooled product could be separated into slag and ingot. An atomic absorption spectrometer was used to determine the metal levels of specimens and toxicity characteristic leaching procedure (TCLP) tests, whereas the crystalline and surface characteristics were examined using quantitative X-ray diffraction (XRD) analysis and scanning electron microscopy, respectively. With a glassy structure, the slag was mainly composed of Ca, Si, and Mg. The TCLP results of slags met the Taiwan regulated standards, suggesting that slag can be used for recycling purposes. With the aid of additives, the crystalline phase of slag was transformed form CaMgSiO4 into CsSiO3. The ingots were mainly composed of Ni (563,000-693,800 mg/kg), Cu (79,900-87,400 mg/kg), and Fe (35,000-43,600 mg/kg) (target metals) due the gravity separation during vitrification. At appropriate additives/sludge ratios (>0.2), >95% of target metals gathered in the ingot as a recoverable form (Ni-Fe alloy). The high Ni level of slag suggests that the ingot can be used as the raw materials for smelters or the additives for steel making. Therefore, the vitrification approach of this study is a promising technology to recover valuable metals from Ni-Cu electroplating sludge. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Recycled asphalt pavement - fly ash geopolymer as a sustainable stabilized pavement material
NASA Astrophysics Data System (ADS)
Horpibulsuk, S.; Hoy, M.; Witchayaphong, P.; Rachan, R.; Arulrajah, A.
2017-11-01
Strength, durability, microstructure and leachate characteristics of Recycled Asphalt Pavement and Fly Ash (RAP-FA) geopolymers and RAP-FA blends as a sustainable pavement material are evaluated in this paper. The strength development of the stabilized materials with and without effect wetting-drying (w-d) cycles was determined by Unconfined Compression Strength (UCS) test. The mineralogical and microstructural changes of the stabilized material were analyzed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The leachability of the heavy metals were measured by Toxicity Characteristic Leaching Procedure (TCLP) and compared with international standard. The results show that both RAP-FA blend and RAP-FA geopolymer increase with increasing the number of w-d cycles (C), reaching its peak at 6 w-d cycles. The XRD and SEM analyses indicate that the strength development of RAP-FA blend occurs due to stimulation of the chemical reaction between the high amount to Calcium in RAP and the high amount of Silica and Alumina in FA leaching to production of Calcium Aluminium (Silicate) Hydrate, while the geopolymerization reaction is observed in RAP-FA geopolymer. For C> 6, the significant macro- and micro-cracks developed during w-d cycles cause strength reduction for both RAP-FA blend and geopolymer. The TCLP results demonstrate that there is no environmental risk for these stabilized materials. Furthermore, FA-geopolymer can reduce the leachability of heavy metal in RAP-FA blend. The outcome from this research confirms the viability of using RAP-FA blend and RAP-FA geopolymer as alternative sustainable pavement materials.
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Ramos-Ruiz, Adriana; Wilkening, Jean V.; Field, James A.; Sierra-Alvarez, Reyes
2017-01-01
A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30 days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1 mg L-1), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005 mg L-1). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. PMID:28472709
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Chapter 6: Selenium Toxicity to Aquatic Organisms
This chapter addresses the characteristics and nature of organic selenium (Se) toxicity to aquatic organisms, based on the most current state of scientific knowledge. As such, the information contained in this chapter relates to the 'toxicity assessment' phase of aquatic ecologi...
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Response Characteristics of an Aquatic Biomonitor Used for Rapid Toxicity Detection
2004-05-15
for drinking water protection. 14. SUBJECT TERMS 15. NUMBER OF PAGES biological early warning system; Lepomis macrochirus; bluegill; aquatic toxicity...Fort Detrick, MD 21702-5010, USA Key words: biomonitor; biological early warning system; Lepomis macrochirus; bluegill; aquatic toxicity; water ...narcosis are most likely to cause rapid aquatic biomonitor depth related to variations in water quality (primarily responses. Other modes of action may
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Evaluation of water treatment sludges toxicity using the Daphnia bioassay.
Sotero-Santos, Rosana B; Rocha, Odete; Povinelli, Jurandyr
2005-10-01
Alum and ferric chloride sludges from two water treatment plants (WTPs) were analyzed regarding their physicochemical characteristics and toxicity to Daphnia similis. Experiments were carried out in the dry and rainy seasons. Acute and chronic toxicity was measured using survival and reproduction as measurement endpoints. No acute toxicity of the sludge was observed in 48 h exposure. Ferric chloride sludge caused chronic toxicity, demonstrated by low fecundity and some mortality, while alum sludge caused chronic toxicity characterized by low fecundity. Some sludge characteristics varied between samplings, including turbidity, solids contents, N, P and metal (Al and Fe) concentrations. These variables and the increase of chemical oxygen demand (COD) were identified as the main cause of degradation of the receiving waters. However, no relationship was observed between these variables and degree of toxicity. It is apparent from these results that water treatment sludges may be toxic and therefore may impair receiving waters. Alum sludge was less toxic than ferric chloride sludge.
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Immobilization in cement mortar of chromium removed from water using titania nanoparticles.
Husnain, Ahmed; Qazi, Ishtiaq Ahmed; Khaliq, Wasim; Arshad, Muhammad
2016-05-01
Because of the high toxicity of chromium, particularly as Cr (VI), it is removed from industrial effluents before their discharge into water bodies by a variety of techniques, including adsorption. Ultimate disposal of the sludge or the adsorbate, however, is a serious problem. While titania, in nanoparticle form, serves as a very good adsorbent for chromium, as an additive, it also helps to increase the compressive strength of mortar and concrete. Combining these two properties of the material, titania nanoparticles were used to adsorb chromium and then added to mortar up to a concentration of 20% by weight. The compressive strength of the resulting mortar specimens that replaced 15% of cement with chromium laden titania showed an improved strength than that without titania, thus confirming that this material had positive effect on the mortar strength. Leachate tests using the Toxicity Characteristics Leaching Procedure (TCLP) confirmed that the mortar sample chromium leachate was well within the permissible limits. The proposed technique thus offers a safe and viable method for the ultimate disposal of toxic metal wastes, in general, and those laden waste chromium, in particular. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Sandeep, P; Sahu, S K; Kothai, P; Pandit, G G
2016-09-01
Studies on leaching behavior of metals associated with coal fly ash (FA) are of great concern because of possible contamination of the aquatic environment. In the present study, leaching behavior of metals (As, Se, Cr, Pb, V, Zn, etc.) in two different FA samples (FA1 and FA2) was investigated at various pH (2-12), temperatures of leachate solution and using TCLP. At pH 2, the highest leaching was observed for Fe (21.6 and 32.8 µg/g), whereas at pH 12, Arsenic was found to have the highest leaching (1.5 and 2.4 µg/g) in FA1 and FA2. Leachate solution temperature showed a positive effect on the metal's leachability. In TCLP, most of the metal's leachability was observed to be higher than that of batch leaching tests. The present study suggests that, leaching of As and Se from FA samples can moderately affect ground/surface water quality at the study locations.
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Co-disposal of electronic waste with municipal solid waste in bioreactor landfills.
Visvanathan, C; Visvanthan, C; Yin, Nang Htay; Karthikeyan, Obuli P
2010-12-01
Three pilot scale lysimeters were adopted to evaluate the stability pattern and leaching potential of heavy metals from MSW landfills under the E-waste co-disposed condition. One lysimeter served as control and solely filled with MSW, whereas the other two lysimeters were provided with 10% and 25% of E-waste scraps (% by weight), respectively. The reactors were monitored over a period of 280 days at ambient settings with continuous leachate recirculation. Stabilization pattern of carbon appears to be more than 50% in all the three lysimeters with irrespective of their operating conditions. Iron and zinc concentrations were high in leachate during bioreactor landfill operation and correlating with the TCLP leachability test results. In contrast, Pb concentration was around <0.6 mg/L, but which showed maximum leaching potential under TCLP test conditions. But, no heavy metal accumulation was found with leachate recirculation practices in lysimeters. Mobility of the metal content from the E-waste was found to be amplified with the long term disposal or stabilization within landfills. The results showed that the TCLP test cannot be completely reliable tool for measuring long-term leachability of toxic substances under landfill condition; rather landfill lysimeter studies are necessary to get the real scenario. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Reduced Toxicity High Performance Monopropellant
2011-09-01
M315E Distribution A: Approved for public release; distribution unlimited AF - M315E Desirable Properties Characteristic Objective D it *I 3450 N /L...required AF M315E d- excee s SOTA monopropellant (45%) and bipropellant (8%) Next generation exceeds SOTA monopropellant (66%) and bipropellant (23...inert mass fraction Distribution A: Approved for public release; distribution unlimited Toxicity Assessment of AF - M315E Toxicity Testing Results
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Li, Yunyi; Cundy, Andrew B; Feng, Jingxuan; Fu, Hang; Wang, Xiaojing; Liu, Yangsheng
2017-05-01
Large amounts of chromite ore processing residue (COPR) wastes have been deposited in many countries worldwide, generating significant contamination issues from the highly mobile and toxic hexavalent chromium species (Cr(VI)). In this study, sodium dithionite (Na 2 S 2 O 4 ) was used to reduce Cr(VI) to Cr(III) in COPR containing high available Fe, and then sodium phosphate (Na 3 PO 4 ) was utilized to further immobilize Cr(III), via a two-step procedure (TSP). Remediation and immobilization processes and mechanisms were systematically investigated using batch experiments, sequential extraction studies, X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Results showed that Na 2 S 2 O 4 effectively reduced Cr(VI) to Cr(III), catalyzed by Fe(III). The subsequent addition of Na 3 PO 4 further immobilized Cr(III) by the formation of crystalline CrPO 4 ·6H 2 O. However, addition of Na 3 PO 4 simultaneously with Na 2 S 2 O 4 (via a one-step procedure, OSP) impeded Cr(VI) reduction due to the competitive reaction of Na 3 PO 4 and Na 2 S 2 O 4 with Fe(III). Thus, the remediation efficiency of the TSP was much higher than the corresponding OSP. Using an optimal dosage in the two-step procedure (Na 2 S 2 O 4 at a dosage of 12× the stoichiometric requirement for 15 days, and then Na 3 PO 4 in a molar ratio (i.e. Na 3 PO 4 : initial Cr(VI)) of 4:1 for another 15 days), the total dissolved Cr in the leachate determined via Toxicity Characteristic Leaching Procedure (TCLP Cr) testing of our samples was reduced to 3.8 mg/L (from an initial TCLP Cr of 112.2 mg/L, i.e. at >96% efficiency). Copyright © 2017 Elsevier Ltd. All rights reserved.
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Soleimanifar, Hanieh; Deng, Yang; Wu, Laying; Sarkar, Dibyendu
2016-07-01
Aluminum-based water treatment residual (WTR)-coated wood mulches were synthesized and tested for removal of heavy metals and phosphorus (P) in synthetic urban stormwater. WTRs are an industrial waste produced from coagulation in water treatment facilities, primarily composed of amorphous aluminum or iron hydroxides. Batch tests showed that the composite filter media could effectively adsorb 97% lead (Pb), 76% zinc (Zn), 81% copper (Cu) and 97% P from the synthetic stormwater (Pb = 100 μg/L, Zn = 800 μg/L, Cu = 100 μg/L, P = 2.30 mg/L, and pH = 7.0) within 120 min, due to the presence of aluminum hydroxides as an active adsorbent. The adsorption was a 2(nd)-order reaction with respect toward each pollutant. Column tests demonstrated that the WTR-coated mulches considerably alleviated the select pollutants under a continuous-flow condition over the entire filtration period. The effluent Pb, Zn, Cu, and P varied at 0.5-8.9%, 33.4-46.7%, 45.8-55.8%, and 6.4-51.9% of their respective initial concentrations with the increasing bed volume from 0 to 50. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) tests indicated that leached contaminants were all below the U.S. criteria, suggesting that the release of undesired chemicals under rainfall or landfilling conditions is not a concern during application. This study demonstrates that the WTR-coated mulches are a new, low-cost, and effective filter media for urban stormwater treatment. Equally important, this study provides a sustainable approach to beneficially reuse an industrial waste for environmental pollution control. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Solidification/stabilization of spent abrasives and use as nonstructural concrete
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brabrand, D.J.; Loehr, R.C.
1993-01-01
Tons of spent abrasives result each year from the removal of old paint from bridges. Because the spent abrasives contain metals from the paint, some spent abrasives may be considered hazardous by the Toxicity Characteristic (TC) criteria. Incorporation of the spent blasting abrasives in nonstructural concrete (rip-rap, dolphins) offers an opportunity to recycle the spent abrasives while immobilizing potentially leachable metals. This study focused on the Portland Cement Solidification/Stabilization (S/S) of spent blasting abrasives taken from a bridge located in Southeast Texas. The study examined (a) the cadmium, chromium, and lead concentrations in extracts obtained by using the Toxicity Characteristicmore » Leaching Procedure (TCLP) and (b) the compressive strengths of Portland Cement mixes that contained different amounts of the spent abrasives. Performance was measured by meeting the TC criteria as well as the requirements for compressive strength. Study results indicated that considerable quantities of these spent abrasives can be solidified/stabilized while reducing the leachability of cadmium, chromium, and lead and producing compressive strengths over 6,895 kN/m[sup 2] (1,000 psi).« less
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Son, Jino; Shin, Key-il; Cho, Kijong
2009-11-01
A central composite design (CCD) was employed to investigate the effects of organic matter (OM) content and soil pH on the reproduction, and chronic toxicity (28-d EC(50-reproduction)) of cadmium for Paronychiurus kimi after 28days exposure in a standard artificial soil. Two statistical models were developed, one describing reproduction in control artificial soils as a function of OM content and pH, and the other describing cadmium toxicity to the same soil parameters. In the reproduction model, pH was the most important factor, followed by two quadratic factors of OM(2) and pH(2). The parameter pH alone could explain 75.5% of the response variation. The reproduction model will allow us to predict a mean reproduction in the non-treated control soils that contain various combinations of OM content and different pH values. In the chronic toxicity model, only the linear factor of the OM content and pH significantly (p<0.05) affect cadmium toxicity, which explains the 78.9% and 14.9% of total response variance, respectively. Therefore, the final polynomial regression describing the chronic toxicity of cadmium to P. kimi is as follows: predicted 28-d EC(50) of cadmium (mgkg(-1))=-21.231+2.794 x OM+4.874 x pH. The present study show that soil characteristics, which can alter the toxicity of cadmium, can also act as stressors themselves in regards to the reproduction of P. kimi. Based on the physico-chemical characteristics of the test media, the response surface model developed in this study can be used to provide initial toxicity information for cadmium within a region of interest in terms of OM content and pH, and may lead to more scientific based risk assessment for metals.
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A mixture toxicity approach to predict the toxicity of Ag decorated ZnO nanomaterials.
Azevedo, S L; Holz, T; Rodrigues, J; Monteiro, T; Costa, F M; Soares, A M V M; Loureiro, S
2017-02-01
Nanotechnology is a rising field and nanomaterials can now be found in a vast variety of products with different chemical compositions, sizes and shapes. New nanostructures combining different nanomaterials are being developed due to their enhancing characteristics when compared to nanomaterials alone. In the present study, the toxicity of a nanostructure composed by a ZnO nanomaterial with Ag nanomaterials on its surface (designated as ZnO/Ag nanostructure) was assessed using the model-organism Daphnia magna and its toxicity predicted based on the toxicity of the single components (Zn and Ag). For that ZnO and Ag nanomaterials as single components, along with its mixture prepared in the laboratory, were compared in terms of toxicity to ZnO/Ag nanostructures. Toxicity was assessed by immobilization and reproduction tests. A mixture toxicity approach was carried out using as starting point the conceptual model of Concentration Addition. The laboratory mixture of both nanomaterials showed that toxicity was dependent on the doses of ZnO and Ag used (immobilization) or presented a synergistic pattern (reproduction). The ZnO/Ag nanostructure toxicity prediction, based on the percentage of individual components, showed an increase in toxicity when compared to the expected (immobilization) and dependent on the concentration used (reproduction). This study demonstrates that the toxicity of the prepared mixture of ZnO and Ag and of the ZnO/Ag nanostructure cannot be predicted based on the toxicity of their components, highlighting the importance of taking into account the interaction between nanomaterials when assessing hazard and risk. Copyright © 2016 Elsevier B.V. All rights reserved.
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Discriminating toxicant classes by mode of action. 1. (Eco)toxicity profiles.
Nendza, Monika; Wenzel, Andrea
2006-05-01
Predictive toxicology, particularly quantitative structure-activity relationships (QSARs), require classification of chemicals by mode of action (MOA). MOA is, however, not a constant property of a compound but it varies between species and may change with concentration and duration of exposure. A battery of MOA-specific in-vitro and low-complexity assays, featuring biomolecular targets for major classes of environmental pollutants, provides characteristic responses for (1.) classification of chemicals by MOA, (2.) identification of (eco)toxicity profiles of chemicals, (3.) identification of chemicals with specific MOAs, (4.) indication of most sensitive species, (5.) identification of chemicals that are outliers in QSARs and (6.) selection of appropriate QSARs for predictions. Chemicals covering nine distinct modes of toxic action (non-polar non-specific toxicants (n=14), polar non-specific toxicants (n=18), uncouplers of oxidative phosphorylation (n=25), inhibitors of photosynthesis (n=15), inhibitors of acetylcholinesterase (n=14), inhibitors of respiration (n=3), thiol-alkylating agents (n=9), reactives (irritants) (n=8), estrogen receptor agonists (n=9)) were tested for cytotoxicity in the neutralred assay, oxygen consumption in isolated mitochondria, oxygen production in algae, inhibition of AChE, reaction with GSH and activity in the yeast estrogen receptor assay. Data on in-vivo aquatic toxicity (LC50, EC50) towards fish, daphnids, algae and bacteria were collected from the literature for reasons of comparison and reference scaling. In the MOA-specific in-vitro test battery, most test chemicals are specifically active at low concentrations, though multiple effects do occur. Graphical and statistical evaluation of the individual classes versus MOA 1 (non-polar non-specific toxicants) identifies interactions related to predominant MOA. Discriminant analyses (DA) on subsets of the data revealed correct classifications between 70% (in-vivo data) and >90% (in
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NASA Astrophysics Data System (ADS)
Gao, Zhengyang; Yang, Weijie; Ding, Xunlei; Lv, Gang; Yan, Weiping
2018-04-01
The effects of support on gas adsorption is crucial for single atom catalysts design and optimization. To gain insight into support effects on gas adsorption characteristics, a comprehensive theoretical study was performed to investigate the adsorption characteristics of toxic gases (NO2, NH3, SO3 and H2S) by utilizing single atom iron catalysts with three graphene-based supports. The adsorption geometry, adsorption energy, electronic and magnetic properties of the adsorption system have been explored. Additionally, the support effects have been analyzed through d-band center and Fermi softness, and thermodynamic analysis has been performed to consider the effect of temperature on gas adsorption. The support effects have a remarkable influence on the adsorption characteristics of four types of toxic gases which is determined by the electronic structure of graphene-based support, and the electronic structure can be characterized by Fermi softness of catalysts. Fermi softness and uplift height of Fe atom could be good descriptors for the adsorption activity of single atom iron catalysts with graphene-based supports. The findings can lay a foundation for the further study of graphene-based support effects in single atom catalysts and provide a guideline for development and design of new graphene-based support materials utilizing the idea of Fermi softness.
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Immobilization of heavy metals in electroplating sludge by biochar and iron sulfide.
Lyu, Honghong; Gong, Yanyan; Tang, Jingcshun; Huang, Yao; Wang, Qilin
2016-07-01
Electroplating sludge (ES) containing large quantities of heavy metals is regarded as a hazardous waste in China. This paper introduced a simple method of treating ES using environmentally friendly fixatives biochar (BC) and iron sulfide (FeS), respectively. After 3 days of treatment with FeS at a FeS-to-ES mass ratio of 1:5, the toxicity characteristic leaching procedure (TCLP)-based leachability of total Cr (TCr), Cu(II), Ni(II), Pb(II), and Zn(II) was decreased by 59.6, 100, 63.8, 73.5, and 90.5 %, respectively. After 5 days of treatment with BC at a BC-to-ES mass ratio of 1:2, the TCLP-based leachability was declined by 35.1, 30.6, 22.3, 23.1, and 22.4 %, respectively. Pseudo first-order kinetic model adequately simulated the sorption kinetic data. Structure and morphology analysis showed that adsorption, electrostatic attraction, surface complexation, and chemical precipitation were dominant mechanisms for heavy metals immobilization by BC, and that chemical precipitation (formation of metal sulfide and hydroxide precipitates), iron exchange (formation of CuFeS2), and surface complexation were mainly responsible for heavy metals removal by FeS. Economic costs of BC and FeS were 500 and 768 CNY/t, lower than that of Na2S (940 CNY/t). The results suggest that BC and FeS are effective, economic, and environmentally friendly fixatives for immobilization of heavy metals in ES before landfill disposal.
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Immobilization of metals in contaminated soils using natural polymer-based stabilizers.
Tao, Xue; Li, Aimin; Yang, Hu
2017-03-01
Three low-cost natural polymer materials, namely, lignin (Ln), carboxymethyl cellulose, and sodium alginate, were used for soil amendment to immobilize lead and cadmium in two contaminated soil samples collected from a mining area in Nanjing, China. The remediation effects of the aforementioned natural polymers were evaluated by toxicity characteristic leaching procedure (TCLP) and sequential extractions. The stabilizers could lower the bioavailability of Pb and Cd in the contaminated soils, and the amount of the exchangeable forms of the aforementioned two metals were reduced evidently. TCLP results showed that the leaching concentrations of Pb and Cd were decreased by 5.46%-71.1% and 4.25%-49.6%, respectively, in the treated soils. The contents of the organic forms of the two metals both increased with the increase in stabilizer dose on the basis of the redistribution of metal forms by sequential extractions. These findings were due to the fact that the abundant oxygen-containing groups on the polymeric amendments were effective in chelating and immobilizing Pb and Cd, which have been further confirmed from the metal adsorptions in aqueous solutions. Moreover, Ln achieved the greatest effect among the three polymers under study because of the former's distinct three-dimensional molecular structure, showing the preferential immobilization of Pb over Cd in soils also. Thus, the above-mentioned natural polymers hold great application potentials for reducing metal ion entry into the food chain at a field scale. Copyright © 2016 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Gong, Yanyan; Liu, Yuanyuan; Xiong, Zhong; Kaback, Dawn; Zhao, Dongye
2012-07-01
Mercury (Hg) is one of the most pervasive and bio-accumulative metals in the environment. Yet, effective in situ remediation technologies have been lacking. This study investigated the effectiveness of a class of soil-deliverable FeS nanoparticles for in situ immobilization of Hg in two field-contaminated soils from a New Jersey site and one sediment from an Alabama site. The nanoparticles were prepared using sodium carboxymethyl cellulose (CMC) as a stabilizer. Transmission electron microscopy measurements revealed a particle size of 34.3 ± 8.3 nm (standard deviation), whereas dynamic light scattering gave a hydrodynamic diameter of 222.5 ± 3.2 nm. Batch tests showed that at an FeS-to-Hg molar ratio of 28:1-118:1, the nanoparticles reduced water-leachable Hg by 79%-96% and the TCLP (toxicity characteristic leaching procedure) based leachability by 26%-96%. Column breakthrough tests indicated that the nanoparticles were deliverable in the sediment/soil columns under moderate injection pressure. However, once the external pressure was removed, the delivered nanoparticles remained virtually mobile under typical groundwater flow conditions. When the Hg-contaminated soil and sediment were treated with 52-95 pore volumes of a 500 mg l-1 FeS nanoparticle suspension, water-leachable Hg was reduced by 90%-93% and TCLP-leachable Hg was reduced by 65%-91%. The results warrant further field demonstration of this promising in situ remediation technology.
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Ramos-Ruiz, Adriana; Wilkening, Jean V; Field, James A; Sierra-Alvarez, Reyes
2017-08-15
A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1mgL -1 ), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005mgL -1 ). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. Copyright © 2017 Elsevier B.V. All rights reserved.
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Moon, Deok Hyun; Hwang, Inseong; Koutsospyros, Agamemnon; Cheong, Kyung Hoon; Ok, Yong Sik; Ji, Won Hyun; Park, Jeong-Hun
2018-05-01
Lead (Pb) and zinc (Zn) contaminated rice paddy soil was stabilized using natural (NSF) and calcined starfish (CSF). Contaminated soil was treated with NSF in the range of 0-10 wt% and CSF in the range of 0-5 wt% and cured for 28 days. Toxicity characteristic leaching procedure (TCLP) test was used to evaluate effectiveness of starfish treatment. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analyses were conducted to investigate the mechanism responsible for effective immobilization of Pb and Zn. Experimental results suggest that NSF and CSF treatments effectively immobilize Pb and Zn in treated rice paddy soil. TCLP levels for Pb and Zn were reduced with increasing NSF and CSF dosage. Comparison of the two treatment methods reveals that CSF treatment is more effective than NSF treatment. Leachability of the two metals is reduced approximately 58% for Pb and 51% for Zn, upon 10 wt% NSF treatment. More pronounced leachability reductions, 93% for Pb and 76% for Zn, are achieved upon treatment with 5 wt% CSF. Sequential extraction results reveal that NSF and CSF treatments of contaminated soil generated decrease in exchangeable/weak acid Pb and Zn soluble fractions, and increase of residual Pb and Zn fractions. Results for the SEM-EDX sample treated with 5 wt% CSF indicate that effective Pb and Zn immobilization is most probably associated with calcium silicate hydrates (CSHs) and calcium aluminum hydrates (CAHs). Copyright © 2018 Elsevier Ltd. All rights reserved.
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Utilization of phosphorus loaded alkaline residue to immobilize lead in a shooting range soil.
Yan, Yubo; Qi, Fangjie; Seshadri, Balaji; Xu, Yilu; Hou, Jiexi; Ok, Yong Sik; Dong, Xiaoli; Li, Qiao; Sun, Xiuyun; Wang, Lianjun; Bolan, Nanthi
2016-11-01
The alkaline residue generated from the production of soda ash using the ammonia-soda method has been successfully used in removing phosphorus (P) from aqueous solution. But the accumulation of P-containing solid after P removal is an undesirable menace to the environment. To achieve the goal of recycling, this study explored the feasibility of reusing the P loaded alkaline residue as an amendment for immobilization of lead (Pb) in a shooting range soil. The main crystalline phase and micromorphology of amendments were determined using X-ray diffraction (XRD) and scanning electron microscopy-electron dispersion spectroscopy (SEM-EDS) methods. The toxicity characteristic leaching procedure (TCLP), sequential extraction procedure, and physiologically based extraction test (PBET) were employed to evaluate the effectiveness of Pb immobilization in soil after 45 d incubation. Treatment with P loaded alkaline residue was significantly effective in reducing the TCLP and PBET extractable Pb concentrations in contrast to the untreated soil. Moreover, a positive change in the distribution of Pb fractions was observed in the treated soil, i.e., more than 60% of soil-Pb was transformed to the residual fraction compared to the original soil. On the other hand, P loaded amendments also resulted in a drastic reduction in phytoavailable Pb to the winter wheat and a mild release of P as a nutrient in treated soil, which also confirmed the improvement of soil quality. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Mercury in aqueous tank waste at the Savannah River Site: Facts, forms, and impacts
Bannochie, C. J.; Fellinger, T. L.; Garcia-Strickland, P.; ...
2017-03-28
Over the past two years, there has been an intense effort to understand the chemistry of mercury across the Savannah River Site’s high-level liquid waste system to determine the impacts of various mercury species. This effort started after high concentrations of mercury were measured in the leachates from a toxicity characteristic leaching procedure (TCLP) test on the low-level cementitious waste form produced in the Savannah River Saltstone facility. Speciation showed the dominant form of leached mercury to be the methylmercury cation. Neither the source of the methylmercury nor its concentration in the Saltstone feed was well established at the timemore » of the testing. Finally, this assessment of mercury was necessary to inform points in the process operations that may be subject to new separation technologies for the removal of mercury.« less
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Mercury in aqueous tank waste at the Savannah River Site: Facts, forms, and impacts
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bannochie, C. J.; Fellinger, T. L.; Garcia-Strickland, P.
Over the past two years, there has been an intense effort to understand the chemistry of mercury across the Savannah River Site’s high-level liquid waste system to determine the impacts of various mercury species. This effort started after high concentrations of mercury were measured in the leachates from a toxicity characteristic leaching procedure (TCLP) test on the low-level cementitious waste form produced in the Savannah River Saltstone facility. Speciation showed the dominant form of leached mercury to be the methylmercury cation. Neither the source of the methylmercury nor its concentration in the Saltstone feed was well established at the timemore » of the testing. Finally, this assessment of mercury was necessary to inform points in the process operations that may be subject to new separation technologies for the removal of mercury.« less
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Modeling Aquatic Toxicity through Chromatographic Systems.
Fernández-Pumarega, Alejandro; Amézqueta, Susana; Farré, Sandra; Muñoz-Pascual, Laura; Abraham, Michael H; Fuguet, Elisabet; Rosés, Martí
2017-08-01
Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.
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Chatterjee, Nivedita; Yang, Ji Su; Park, Kwangsik; Oh, Seung Min; Park, Jeonggue; Choi, Jinhee
2015-01-01
The widely promising applications of graphene nanomaterials raise considerable concerns regarding their environmental and human health risk assessment. The aim of the current study was to evaluate the toxicity profiling of graphene family nananomaterials (GFNs) in alternative in vitro and in vivo toxicity testing models. The GFNs used in this study are graphene nanoplatelets ([GNPs]-pristine, carboxylate [COOH] and amide [NH2]) and graphene oxides (single layer [SLGO] and few layers [FLGO]). The human bronchial epithelial cells (Beas2B cells) as in vitro system and the nematode Caenorhabditis elegans as in vivo system were used to profile the toxicity response of GFNs. Cytotoxicity assays, colony formation assay for cellular toxicity and reproduction potentiality in C. elegans were used as end points to evaluate the GFNs' toxicity. In general, GNPs exhibited higher toxicity than GOs in Beas2B cells, and among the GNPs the order of toxicity was pristine>NH2>COOH. Although the order of toxicity of the GNPs was maintained in C. elegans reproductive toxicity, but GOs were found to be more toxic in the worms than GNPs. In both systems, SLGO exhibited profoundly greater dose dependency than FLGO. The possible reason of their differential toxicity lay in their distinctive physicochemical characteristics and agglomeration behavior in the exposure media. The present study revealed that the toxicity of GFNs is dependent on the graphene nanomaterial's physical forms, surface functionalizations, number of layers, dose, time of exposure and obviously, on the alternative model systems used for toxicity assessment.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Neeway, James J.; Qafoku, Nikolla; Brown, Christopher F.
2013-10-01
Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. This goal of this campaign was study the durability of the FBSR mineral product and the mineral product encapsulated in a monolith to meet compressive strength requirements. This paper gives anmore » overview of results obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Neeway, James J.; Qafoku, Nikolla P.; Peterson, Reid A.
2013-07-01
Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. The goal of this campaign was to study the durability of the FBSR mineral product and the encapsulated FBSR product in a geo-polymer monolith. This paper gives an overview of resultsmore » obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory. (authors)« less
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[Advances in studies on toxicity of aconite].
Chen, Rong-Chang; Sun, Gui-Bo; Zhang, Qiang; Ye, Zu-Guang; Sun, Xiao-Bo
2013-04-01
Aconite has the efficacy of reviving yang for resuscitation, dispelling cold and relieving pain, which is widely used in clinic, and shows unique efficacy in treating severe diseases. However, aconite has great toxicity, with obvious cardio-toxicity and neurotoxicity. Its toxicological mechanism main shows in the effect on voltage-dependent sodium channels, release of neurotransmitters and changes in receptors, promotion of lipid peroxidation and cell apoptosis in heart, liver and other tissues. Aconite works to reduce toxicity mainly through compatibility and processing. Besides traditional processing methods, many new modern processing techniques could also help achieve the objectives of detoxification and efficacy enhancement. In order to further develop the medicinal value of aconite and reduce its side effect in clinical application, this article gives comprehensive comments on aconite's toxicity characteristics, mechanism and detoxification methods on the basis of relevant reports for aconite's toxicity and the author's experimental studies.
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Alkali borosilicate glass by fly ash from a coal-fired power plant.
Park, Jong Soo; Taniguchi, Shoji; Park, Young Jun
2009-01-01
The possibility of using coal fly ash as a silica source for alkali borosilicate glass was investigated. Alkali borosilicate glasses were prepared from the coal fly ash mixed with 30 wt.% reagents composed of Na(2)O and B(2)O(3) by susceptor-induction heating. Their densities ranged from 2.24 to 2.55 g cm(-3) and decreased as the amount of B(2)O(3) addition increased. However, the Vickers microhardness showed a different tendency with the density since the glass network connectivity improved by boron anomaly, which was identified by a nuclear magnetic resonance analysis. The Vickers microhardness of the glass product, with the addition of 15 wt.% B(2)O(3) and 15 wt.% Na(2)O, was about 4030 MPa. Furthermore, the changes in microstructure were consistent with those in the chemical stability by the toxicity characteristic leaching procedure (TCLP).
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Fu, Fenglian; Zeng, Haiyan; Cai, Qinhong; Qiu, Rongliang; Yu, Jimmy; Xiong, Ya
2007-11-01
A new dithiocarbamate-type heavy metal precipitant, sodium 1,3,5-hexahydrotriazinedithiocarbamate (HTDC), was prepared and used to remove coordinated copper from wastewater. In the reported dithiocarbamate-type precipitants, HTDC possesses the highest percentage of the effective functional groups. It could effectively precipitate copper to less than 0.5mgl(-1) from both synthetic and actual industrial wastewater containing CuEDTA in the range of pH 3-9. UV-vis spectral investigation and elemental analysis suggested that the precipitate was a kind of coordination supramolecular compound, [Cu(3)(HTDC)(2)](n). The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the supramolecular precipitate was non-hazardous and stable in weak acid and alkaline conditions. Tests of an anion exchange resin D231 provided a clue to simultaneously remove excess HTDC and residual CuEDTA in practical process of wastewater treatment.
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Boron toxicity characteristics of four northern California endemic tree species
DOE Office of Scientific and Technical Information (OSTI.GOV)
Glaubig, B.A.; Bingham, F.T.
A greenhouse study was undertaken to determine the characteristics of soil B toxicity for four tree species endemic to The Geysers area in northern California: digger pine (Pinus sabiniana Dougl. ex D. Don), California laurel (or, California bay) (Umbellularia californica (Hoo. and Arn. Nutt.)), madrone (Arbutus menziesii Pursh), and bigleaf maple (Acer macrophyllum Pursh). Significant exponential relationships were found between soil B concentration and relative growth, and between tissue B concentration and relative growth for the four species. Significant linear relationships were found between both soil and tissue B concentration and foliar damage for the four species. Foliar damages overmore » 25% of the leaf or needle area on digger pine, California laurel, madrone, and bigleaf maple, respectively, occurred at saturated soil extract concentrations (mmol B/L) of 1.2, 0.4, 0.5, and 0.08. Twenty-five percent foliar damage was associated with leaf or needle tissue concentrations (mmol B/kg) of 115, 100, 50, and 30 for the digger pine, California laurel, madrone, and bigleaf maple, respectively. Growth decrements of 25% occurred at saturated soil extract concentrations (mmol B/L) of 1.6, 0.3, 0.2, 0.5 for the digger pine, California laurel, madrone, and bigleaf maple, respectively. Twenty-five percent growth decrements were associated with leaf or needle tissue concentrations (mmol B/kg) of 140, 100, 20, and 7 for the digger pine, California laurel, madrone, and bigleaf maple, respectively. By comparison with two agronomic crops - cotton (Gossypium hirsutum L.) and cowpea (Vigna unguiculata L.) - the four tree species were placed into one of six B tolerance classes.« less
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Stabilization of heavy metals in soil using two organo-bentonites.
Yu, Kai; Xu, Jian; Jiang, Xiaohong; Liu, Cun; McCall, Wesley; Lu, Jinlong
2017-10-01
Stabilization of Cu, Zn, Cd, Hg, Cr and As in soil using tetramethylammonium (TMA) and dodecyltrimethylammonium (DTMA) modified bentonites (T-Bents and D-Bents) as amendments was investigated. Toxicity characteristic leaching procedure (TCLP) was used to quantify the metal mobility after soil treatment. The structural parameters of modified bentonites, including the BET surface area, basal spacing and zeta potential were obtained as a function of the TMA and DTMA loading at 40, 80, 120, 160 and 200% of the bentonite's cation exchange capacity, respectively. The results indicated that the characteristics of the organo-bentonites fundamentally varied depending on the species and concentration of modifiers loaded on bentonite. T-Bents and D-Bents manifested distinct immobilization effectiveness towards various metals. In association with the organo-bentonite characteristics, the main interactive mechanisms for Cu, Zn and Cd proceeded via cation exchange, Hg proceeded via physical adsorption and partitioning, Cr and As proceeded via specific adsorption and electrostatic attraction, respectively. This study provided operational and mechanistic basis for optimizing the organic clay synthesis and selecting as the appropriate amendment for remediation of heavy metal contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Islam, M. Ashraful; Beardall, John
2017-01-01
Cyanobacteria are major bloom-forming organisms in freshwater ecosystems and many strains are known to produce toxins. Toxin production requires an investment in energy and resources. As light is one of the most important factors for cyanobacterial growth, any changes in light climate might affect cyanobacterial toxin production as well as their growth and physiology. To evaluate the effects of light on the growth and physiological parameters of both toxic and non-toxic strains of Microcystis aeruginosa and Anabaena circinalis, cultures were grown at a range of light intensities (10, 25, 50, 100, 150 and 200 µmol m−2 s−1). The study revealed that the toxic strains of both species (CS558 for M. aeruginosa and CS537 and CS541 for A. circinalis) showed growth (µ) saturation at a higher light intensity compared to the non-toxic strains (CS338 for M. aeruginosa and CS534 for A. circinalis). Both species showed differences in chlorophyll a, carotenoid, allophycocyanin (APC) and phycoerythrin (PE) content between strains. There were also differences in dark respiration (Rd), light saturated oxygen evolution rates (Pmax) and efficiency of light harvesting (α) between strains. All other physiological parameters showed no statistically significant differences between strains. This study suggest that the different strains respond differently to different light habitats. Thus, changes in light availability may affect bloom intensity of toxic and nontoxic strains of cyanobacteria by changing the dominance and succession patterns. PMID:28777340
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Cadmium telluride leaching behavior: Discussion of Zeng et al. (2015).
Sinha, Parikhit
2015-11-01
Zeng et al. (2015) evaluate the leaching behavior and surface chemistry of II-VI semiconductor materials, CdTe and CdSe, in response to pH and O2. Under agitation in acidic and aerobic conditions, the authors found approximately 3.6%-6.4% (w/w) solubility of Cd content in CdTe in the Toxicity Characteristic Leaching Procedure (TCLP), Waste Extraction Test (WET), and dissolution test, with lower solubility (0.56-0.58%) under agitation in acidic and anoxic conditions. This range is comparable with prior long-term transformation and dissolution testing and bio-elution testing of CdTe (2.3%-4.1% w/w solubility of Cd content in CdTe). The implications for potential leaching behavior of CdTe-containing devices require further data. Since CdTe PV modules contain approximately 0.05% Cd content by mass, the starting Cd content in the evaluation of CdTe-containing devices would be lower by three orders of magnitude than the starting Cd content in the authors' study, and leaching potential would be further limited by the monolithic glass-adhesive laminate-glass structure of the device that encapsulates the semiconductor material. Experimental evaluation of leaching potential of CdTe PV modules crushed by landfill compactor has been conducted, with results of TCLP and WET tests on the crushed material below regulatory limits for Cd. CdTe PV recycling technology has been in commercial operation since 2005 with high yields for semiconductor (95%) and glass (90%) recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.
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The use of municipal sewage sludge for the stabilization of soil contaminated by mining activities.
Theodoratos, P; Moirou, A; Xenidis, A; Paspaliaris, I
2000-10-02
The ability of municipal sewage sludge to immobilize Pb, Zn and Cd contained in contaminated soil originating from a former mining area in Lavrion, Greece was investigated. The soil was cured with sewage sludge in various proportions. The stabilization was evaluated primarily by applying chemical tests and complemented by the performance of additional biological tests. Application of the U.S. EPA Toxicity Characteristic Leaching Procedure (TCLP) on the stabilized mixtures proved that Pb, Zn and Cd solubility was reduced by 84%, 64% and 76%, respectively, at 15% w/w sludge addition, while a 10% w/w addition was sufficient to reduce Pb solubility below the U.S. EPA TCLP regulatory limit. The results of the extraction using EDTA solution showed the same trend, resulting in 26%, 36% and 53% reduction in the Pb, Zn and Cd extractable fractions, respectively. Speciation analysis of the treated soils revealed a significant decrease in the mobile fractions of heavy metals, which was attributed to their retention in sewage sludge by adsorption and organic complexation mechanisms. For the assessment of possible phytotoxicity, experiments including growing dwarf beans in the treated soil was carried out. It was found that sewage sludge addition had a positive effect on plant growth. Furthermore, the Pb and Zn uptake of plant leaves and roots was reduced, while Cd uptake was unaffected by the sludge treatment. The results of this study support the hypothesis that municipal sewage sludge is a potential effective stabilizing agent for contaminated soil containing Pb, Zn and Cd.
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Sizochenko, Natalia; Rasulev, Bakhtiyor; Gajewicz, Agnieszka; Kuz'min, Victor; Puzyn, Tomasz; Leszczynski, Jerzy
2014-11-21
Many metal oxide nanoparticles are able to cause persistent stress to live organisms, including humans, when discharged to the environment. To understand the mechanism of metal oxide nanoparticles' toxicity and reduce the number of experiments, the development of predictive toxicity models is important. In this study, performed on a series of nanoparticles, the comparative quantitative-structure activity relationship (nano-QSAR) analyses of their toxicity towards E. coli and HaCaT cells were established. A new approach for representation of nanoparticles' structure is presented. For description of the supramolecular structure of nanoparticles the "liquid drop" model was applied. It is expected that a novel, proposed approach could be of general use for predictions related to nanomaterials. In addition, in our study fragmental simplex descriptors and several ligand-metal binding characteristics were calculated. The developed nano-QSAR models were validated and reliably predict the toxicity of all studied metal oxide nanoparticles. Based on the comparative analysis of contributed properties in both models the LDM-based descriptors were revealed to have an almost similar level of contribution to toxicity in both cases, while other parameters (van der Waals interactions, electronegativity and metal-ligand binding characteristics) have unequal contribution levels. In addition, the models developed here suggest different mechanisms of nanotoxicity for these two types of cells.
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Lopes, T.J.; Fossum, K.D.
1995-01-01
Statistical analyses indicated that urban stormwater could degrade the quality of streamflow because of oil and grease, pesticides, dissolved trace metals, and ammonia in stormwater. Ammonia, lead, cadmium, and zinc are released by urban activities and accumulate in bed material. Ammonia could be from fertilizers, fecal matter, and other sources. Lead is probably from vehicles that use leaded gasoline. Cadmium and zinc could be from particulate metal in oil, brake pads, and other sources. Samples of the initial runoff from urban drainage basins appeared to be more toxic than flow-weighted composite samples, and stormwater was more harmful to fathead minnows than to Ceriodaphnia dubia. Streamflow samples from the Salt River were not toxic to either species. The sensitivity of fathead minnows to urban stormwater from most urban drainage basins indicated that the toxicants were detrimental to fish and could be present in stormwater throughout Phoenix. Results of toxicity identification evaluations indicated the toxicity was mostly due to organic constituents. Mortality, however, did not correlate with organophosphate pesticide concentrations. Surfactants and (or) other constituents leached from asphalt could be toxic. The most toxic bed-material samples were collected from an undeveloped drainage basin. Within urban-drainage basins, bed-material samples collected where stormwater accumulates appeared to be more toxic than samples collected from areas unaffected by stormwater. Mortality rates correlated with recoverable concentrations of zinc, copper, and cadmium; however these rates correlated poorly with pesticide concentrations. The bioavailability of trace metals appeared to be controlled by the adsorption properties of bed material.
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Yutong, Zong; Qing, Xiao; Shenggao, Lu
2016-07-01
This study examines the distribution, mobility, and potential environmental risks of heavy metals in various particle size fractions of urban soils. Representative urban topsoils (ten) collected from Anshan, Liaoning (northeastern China), were separated into six particle size fractions and their heavy metal contents (Cr, Cu, Cd, Pb, and Zn) were determined. The bioaccessibility and leachability of heavy metals in particle size fractions were evaluated using the toxicity characteristic leaching procedure (TCLP) and ethylenediaminetetraacetic acid (EDTA) extraction, respectively. The results indicated that the contents of five heavy metals (Cd, Cr, Cu, Pb and Zn) in the size fractions increased with the decrease of particle size. The clay fraction of <2 μm had the highest content of heavy metals, indicating that the clay fraction was polluted by heavy metals more seriously than the other size fractions in urban topsoils. Cr also concentrated in the coarse fraction of 2000-1000 μm, indicating a lithogenic contribution. However, the dominant size fraction responsible for heavy metal accumulation appeared to belong to particle fraction of 50-2 μm. The lowest distribution factors (DFs) of heavy metals were recorded in the 2000- to 1000-μm size fraction, while the highest in the clay fraction. The DFs of heavy metals in the clay fraction followed Zn (3.22) > Cu (2.84) > Pb (2.61) > Cr (2.19) > Cd (2.05). The enrichment factor suggested that the enrichment degree of heavy metal increased with the decrease of the particle size, especially for Cd and Zn. The TCLP- and EDTA-extractable concentrations of heavy metals in the clay fraction were relatively higher than those in coarse particles. Cd bioavailability was higher in the clay fraction than in other fractions or whole soils. In contrast, Cr exhibits similar bioaccessibilities in the six size fractions of soils. The results suggested that fine particles were the main sources of potentially toxic
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Arsenic Speciation of Solvent-Extracted Leachate from New and Weathered CCA-Treated Wood
KHAN, BERNINE I.; SOLO - GABRIELE, HELENA M.; DUBEY, BRAJESH K.; TOWNSEND, TIMOTHY G.; CAI, YONG
2009-01-01
For the past 60 yr, chromate-copper-arsenate (CCA) has been used to pressure-treat millions of cubic meters of wood in the United States for the construction of many outdoor structures. Leaching of arsenic from these structures is a possible health concern as there exists the potential for soil and groundwater contamination. While previous studies have focused on total arsenic concentrations leaching from CCA-treated wood, information pertaining to the speciation of arsenic leached is limited. Since arsenic toxicity is dependent upon speciation, the objective of this study was to identify and quantify arsenic species leaching from new and weathered CCA-treated wood and CCA-treated wood ash. Solvent-extraction experiments were carried out by subjecting the treated wood and the ash to solvents of varying pH values, solvents defined in the EPA’s Synthetic Precipitation Leaching Procedure (SPLP) and Toxicity Characteristic Leaching Procedure (TCLP), rainwater, deionized water, and seawater. The generated leachates were analyzed for inorganic As(III) and As(V) and the organoarsenic species, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), using high-performance liquid chromatography followed by hydride generation and atomic fluorescence spectrometry (HPLC–HG-AFS). Only the inorganic species were detected in any of the wood leachates; no organoarsenic species were found. Inorganic As(V) was the major detectable species leaching from both new and weathered wood. The weathered wood leached relatively more overall arsenic and was attributed to increased inorganic As(III) leaching. The greater presence of As(III) in the weathered wood samples as compared to the new wood samples may be due to natural chemical and biological transformations during the weathering process. CCA-treated wood ash leached more arsenic than unburned wood using the SPLP and TCLP, and ash samples leached more inorganic As(III) than the unburned counterparts. Increased leaching was due
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Acute toxicity of ingested fluoride.
Whitford, Gary Milton
2011-01-01
This chapter discusses the characteristics and treatment of acute fluoride toxicity as well as the most common sources of overexposure, the doses that cause acute toxicity, and factors that can influence the clinical outcome. Cases of serious systemic toxicity and fatalities due to acute exposures are now rare, but overexposures causing toxic signs and symptoms are not. The clinical course of systemic toxicity from ingested fluoride begins with gastric signs and symptoms, and can develop with alarming rapidity. Treatment involves minimizing absorption by administering a solution containing calcium, monitoring and managing plasma calcium and potassium concentrations, acid-base status, and supporting vital functions. Approximately 30,000 calls to US poison control centers concerning acute exposures in children are made each year, most of which involve temporary gastrointestinal effects, but others require medical treatment. The most common sources of acute overexposures today are dental products - particularly dentifrices because of their relatively high fluoride concentrations, pleasant flavors, and their presence in non-secure locations in most homes. For example, ingestion of only 1.8 ounces of a standard fluoridated dentifrice (900-1,100 mg/kg) by a 10-kg child delivers enough fluoride to reach the 'probably toxic dose' (5 mg/kg body weight). Factors that may influence the clinical course of an overexposure include the chemical compound (e.g. NaF, MFP, etc.), the age and acid-base status of the individual, and the elapsed time between exposure and the initiation of treatment. While fluoride has well-established beneficial dental effects and cases of serious toxicity are now rare, the potential for toxicity requires that fluoride-containing materials be handled and stored with the respect they deserve. Copyright © 2011 S. Karger AG, Basel.
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Passino-Reader, D.R.; Hickey, J.P.; Ogilvie, L.M.
1997-01-01
The objectives of this study were (1) to determine the toxicity of several types of polycyclic hydrocarbons characteristic of Great Lakes samples to Daphnia pulex, a Great Lakes zooplankter, (2) to investigate the influence of different structural characteristics on toxicity, and (3) to determine the linear solvation energy relationship (LSER) parameters and model that describe these compounds. These results will be related to comparative toxicity of other Great Lakes environmental compounds and to their application in site specific risk assessment.
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[Staphylococcal toxin of toxic shock syndrome].
Fluer, F S
2007-01-01
Literature data on toxic shock syndrome staphylococcal toxin (TSST-1) are summarized; properties of Staphylococcus aureus strains producing TSST-1, nutrient media, and factors influencing on production of TSST-1 are reviewed. Physical and chemical properties of the toxin, its molecular characteristics, genetic regulation of its production, mechanism of action, and diseases which it causes are also discussed. Clinical and histologic signs of toxic shock syndrome (TSS), its diagnostic criteria, susceptibility of people to TSS, antigenic and serologic properties of the toxin, epidemiology of the infection caused by TSST-1-producing strains of staphylococci, methods of TSST-1 extraction and identification are described.
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Murine Toxicity of Cochliobolus carbonum1
Hamilton, Pat B.; Nelson, R. R.; Harris, B. S. H.
1968-01-01
Seventeen wild-type strains of the phytopathogenic fungus Cochliobolus carbonum, tested by intraperitoneal injection into mice, were lethal within 48 hr. The lethal effect appeared to be a toxic rather than an infectious process, because death occurred within 3 hr after injection of two of the isolates and heat-killed cultures were lethal. Assays of ascospore progeny from two crosses involving three isolates indicated that the toxic metabolites were under genetic control and quantitative regulation. Studies of the toxicological, cultural, and chemical characteristics of these three strains indicated that more than one murine toxin was present. PMID:16349821
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Immobilization and phytotoxicity of chromium in contaminated soil remediated by CMC-stabilized nZVI.
Wang, Yu; Fang, Zhanqiang; Kang, Yuan; Tsang, Eric Pokeung
2014-06-30
The toxic effect of Cr(VI)-contaminated soil remediated by sodium carboxymethyl cellulose stabilized nanoscale zero-valent iron (CMC-stabilized nZVI) was assessed through in vitro toxicity and phytotoxicity tests. In vitro tests showed that 0.09 g L(-1) of Fe(0) nanoparticles (soil-to-solution ratio was 1 g:5 mL) significantly reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiological based extraction test (PBET) bioaccessibility of Cr by 82% and 58%, respectively. Sequential extraction procedures (SEP) revealed that exchangeable (EX) Cr was completely converted to Fe-Mn oxides (OX) and organic matter (OM). Accordingly, phytotoxicity tests indicated that after 72-h remediation, Cr uptakes by edible rape and Chinese cabbage were suppressed by 61% and 36%, respectively. Moreover, no significant increase in Cr uptake was observed for either species after a 1-month static period for the amended soil. Regarding Fe absorption, germination and seedling growth, both plant species were significantly affected by CMC-nZVI-exposed soils. However, similar phytotoxicity tests conducted after 1 month showed an improvement in cultivation for both plants. Overall, this study demonstrated that CMC-nZVI could significantly enhance Cr immobilization, which reduced its leachability, bioavailability and bioaccumulation by plants. From a detoxification perspective, such remediation is technologically feasible and shows great potential in field applications. Copyright © 2014 Elsevier B.V. All rights reserved.
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Reduction of Cr(VI) to Cr(III) in Artificially-Contaminated Soil using Chemical Reagents
NASA Astrophysics Data System (ADS)
Kostarelos, Konstantinos; Rao, Ennio; Reale, Daniela
2010-05-01
The presence of hexavalent chromium (CrVI) in soil is an environmental concern due to its effect on human health. The concern arises from the leaching and the seepage of Cr(VI) from soil to groundwater. A remediation approach that has been studied in the literature is that of reducing the hexavalent chromium to its trivalent form using a chemical reagent, namely ferrous sulfate heptahydrate (FeSO4.7H20). In this study, we compared performance of ferrous sulfate heptahydrate to sodium thiosulfate (Na2S2O3), a less costly reductant. The means of measuring the performance of the reductants is the US EPA's Toxicity Characteristic Leaching Procedure (TCLP), which states that the total chromium release from the soil must be less than 5 ppm. Because this treatment approach is pH sensitive and thus, susceptible to acid rain effects, it was studied with the intention that it be coupled with a stabilization/fixation approach so as to provide a second level of treatment; i.e., it is not intended to be the stand-alone treatment approach. In this study, the reductants were initially used to treat a contaminated, artificial soil and allowed to cure for varying time periods to determine the minimum curing time. Contaminated artificial soil were then prepared using the same percentage of white sand, kaolinite clay and potassium chromate and varying amount of water as a function of the humidity of the specimens in order to illucidate the effect of moisture on the reductant performance. Finally, the reductant (either ferrous sulfate heptahydrate or sodium thiosulfate) was added in varying doses to determine the best ratio Cr/reagent dose. Chromium release from the soil was evaluated with a modified Toxicity Characteristic Leaching Procedure (TCLP) test after allowing the samples to cure. Results indicated that chromium(VI) released from the specimens was less than 5 ppm for the samples treated with either ferrous sulfate heptahydrate (99.9% of reduction) and sodium thiosulfate (98
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Xu, Piao; Lai, Cui; Zeng, Guangming; Huang, Danlian; Chen, Ming; Song, Biao; Peng, Xin; Wan, Jia; Hu, Liang; Duan, Abing; Tang, Wangwang
2018-02-01
Composting is identified as an effective approach for solid waste disposal. The bioremediation of 4-nonylphenol (4NP) and cadmium (Cd) co-contaminated sediment was investigated by composting with Phanerochaete chrysosporium (P. chrysosporium) inocula. P. chrysosporium inocula and proper C/N ratios (25.51) accelerated the composting process accompanied with faster total organic carbon loss, 4NP degradation and Cd passivation. Microbiological analysis demonstrated that elevated activities of lignocellulolytic enzymes and sediment enzymes was conducive to organic chemical transformation. Bacterial community diversity results illustrated that Firmicutes and Proteobacteria were predominant species during the whole composting process. Aerobic cellulolytic bacteria and organic degrading species played significant roles. Toxicity characteristic leaching procedure (TCLP) extraction and germination indices results indicated the efficient detoxification of 4NP and Cd co-contaminated sediment after 120 days of composting. Overall, results demonstrated that P. chrysosporium enhanced composting was available for the bioremediation of 4NP and Cd co-contaminated sediment. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Shan, Jilei; Sáez, A Eduardo; Ela, Wendell P
2010-02-01
Many water treatment technologies for arsenic removal that are used today produce arsenic-bearing residuals which are disposed in non-hazardous landfills. Previous works have established that many of these residuals will release arsenic to a much greater extent than predicted by standard regulatory leaching tests (e.g. the toxicity characteristic leaching procedure, TCLP) and, consequently, require stabilization to ensure benign behavior after disposal. In this work, a four-step sequential extraction method was developed in an effort to determine the proportion of arsenic in various phases in untreated as well as stabilized iron-based solid matrices. The solids synthesized using various potential stabilization techniques included: amorphous arsenic-iron sludge (ASL), reduced ASL via reaction with zero valent iron (RASL), amorphous ferrous arsenate (PFA), a mixture of PFA and SL (M1), crystalline ferrous arsenate (HPFA), and a mixture of HPFA and SL (M2). The overall arsenic mobility of the tested samples increased in the following order: ASL > RASL > PFA > M1 > HPFA > M2.
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Toxicity of carbamates for mammals
Vandekar, M.; Pleština, R.; Wilhelm, K.
1971-01-01
Toxicity studies have been carried out with a number of monomethylcarbamates, most of which reached an advanced stage in the World Health Organization insecticide evaluation programme. Both quantitative and qualitative distinctions have been found between the carbamates studied, and certain common characteristics that distinguish them in several important aspects from organophosphorus insecticides have been demonstrated. PMID:4999482
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Jensen, Ellen K.; Larsen, Sten Y.; Nygaard, Unni C.; Marioara, Calin D.; Syversen, Tore
2012-01-01
This paper describes an approach for the early combination of material characterization and toxicology testing in order to design carbon nanofiber (CNF) with low toxicity. The aim was to investigate how the adjustment of production parameters and purification procedures can result in a CNF product with low toxicity. Different CNF batches from a pilot plant were characterized with respect to physical properties (chemical composition, specific surface area, morphology, surface chemistry) as well as toxicity by in vitro and in vivo tests. A description of a test battery for both material characterization and toxicity is given. The results illustrate how the adjustment of production parameters and purification, thermal treatment in particular, influence the material characterization as well as the outcome of the toxic tests. The combination of the tests early during product development is a useful and efficient approach when aiming at designing CNF with low toxicity. Early quality and safety characterization, preferably in an iterative process, is expected to be efficient and promising for this purpose. The toxicity tests applied are preliminary tests of low cost and rapid execution. For further studies, effects such as lung inflammation, fibrosis and respiratory cancer are recommended for the more in-depth studies of the mature CNF product.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Eibling, R.
Savannah River National Laboratory (SRNL) was asked to prepare saltstone from samples of Tank 50H obtained by SRNL on April 5, 2011 (Tank 50H sampling occurred on April 4, 2011) during 2QCY11 to determine the non-hazardous nature of the grout and for additional vault classification analyses. The samples were cured and shipped to Babcock & Wilcox Technical Services Group-Radioisotope and Analytical Chemistry Laboratory (B&W TSG-RACL) to perform the Toxic Characteristic Leaching Procedure (TCLP) and subsequent extract analysis on saltstone samples for the analytes required for the quarterly analysis saltstone sample. In addition to the eight toxic metals - arsenic, barium,more » cadmium, chromium, mercury, lead, selenium and silver - analytes included the underlying hazardous constituents (UHC) antimony, beryllium, nickel, and thallium which could not be eliminated from analysis by process knowledge. Additional inorganic species determined by B&W TSG-RACL include aluminum, boron, chloride, cobalt, copper, fluoride, iron, lithium, manganese, molybdenum, nitrate/nitrite as Nitrogen, strontium, sulfate, uranium, and zinc and the following radionuclides: gross alpha, gross beta/gamma, 3H, 60Co, 90Sr, 99Tc, 106Ru, 106Rh, 125Sb, 137Cs, 137mBa, 154Eu, 238Pu, 239/240Pu, 241Pu, 241Am, 242Cm, and 243/244Cm. B&W TSG-RACL provided subsamples to GEL Laboratories, LLC for analysis for the VOCs benzene, toluene, and 1-butanol. GEL also determines phenol (total) and the following radionuclides: 147Pm, 226Ra and 228Ra. Preparation of the 2QCY11 saltstone samples for the quarterly analysis and for vault classification purposes and the subsequent TCLP analyses of these samples showed that: (1) The saltstone waste form disposed of in the Saltstone Disposal Facility in 2QCY11 was not characteristically hazardous for toxicity. (2) The concentrations of the eight RCRA metals and UHCs identified as possible in the saltstone waste form were present at levels below the UTS. (3) Most of the
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Parry, Emily; Lesmeister, Sarah; Teh, Swee; Young, Thomas M
2015-10-01
Bifenthrin is a pyrethroid pesticide that is highly toxic to aquatic invertebrates. The dissolved concentration is generally thought to be the best predictor of acute toxicity. However, for the filter-feeding calanoid copepods Eurytemora affinis and Pseudodiaptomus forbesi, ingestion of pesticide-bound particles could prove to be another route of exposure. The present study investigated bifenthrin toxicity to E. affinis and P. forbesi in the presence of suspended solids from municipal wastewater effluent and surface water of the San Francisco (CA, USA) Estuary. Suspended solids mitigated the toxicity of total bifenthrin to E. affinis and P. forbesi, but mortality was higher than what would be predicted from dissolved concentrations alone. The results indicate that the toxicity and bioavailability of particle-associated bifenthrin was significantly correlated with counts of 0.5-µm to 2-µm particle sizes. Potential explanations could include direct ingestion of bifenthrin-bound particles, changes in food consumption and feeding behavior, and physical contact with small particles. The complex interactions between pesticides and particles of different types and sizes demonstrate a need for future ecotoxicological studies to investigate the role of particle sizes on aquatic organisms. © 2015 SETAC.
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Prediction of pesticide toxicity in Midwest streams
Shoda, Megan E.; Stone, Wesley W.; Nowell, Lisa H.
2016-01-01
The occurrence of pesticide mixtures is common in stream waters of the United States, and the impact of multiple compounds on aquatic organisms is not well understood. Watershed Regressions for Pesticides (WARP) models were developed to predict Pesticide Toxicity Index (PTI) values in unmonitored streams in the Midwest and are referred to as WARP-PTI models. The PTI is a tool for assessing the relative toxicity of pesticide mixtures to fish, benthic invertebrates, and cladocera in stream water. One hundred stream sites in the Midwest were sampled weekly in May through August 2013, and the highest calculated PTI for each site was used as the WARP-PTI model response variable. Watershed characteristics that represent pesticide sources and transport were used as the WARP-PTI model explanatory variables. Three WARP-PTI models—fish, benthic invertebrates, and cladocera—were developed that include watershed characteristics describing toxicity-weighted agricultural use intensity, land use, agricultural management practices, soil properties, precipitation, and hydrologic properties. The models explained between 41 and 48% of the variability in the measured PTI values. WARP-PTI model evaluation with independent data showed reasonable performance with no clear bias. The models were applied to streams in the Midwest to demonstrate extrapolation for a regional assessment to indicate vulnerable streams and to guide more intensive monitoring.
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Aquatic toxicity of petroleum products and dispersant agents ...
The U.S. EPA Office of Research and Development has developed baseline data on the ecotoxicity of selected petroleum products and several chemical dispersants as part of its oil spills research program. Two diluted bitumens (dilbits) from the Alberta Tar Sands were tested for acute and chronic toxicity to standard freshwater and marine organisms given their spill potential during shipment within the United States. Separately, two reference crude oils representing a range of characteristics, and their mixtures with four representative dispersants, were tested to evaluate acute and chronic toxicity to marine organisms in support of Subpart J of the U.S. National Contingency Plan. Water accommodated fractions (WAF) of oil were prepared using traditional slow-stir methods and toxicity tests generally followed U.S. EPA standard effluent testing guidelines. WAFs were characterized for petroleum hydrocarbons including alkyl PAH homologs. The results of these studies will assist the U.S. EPA to assess toxicity data for unconventional oils (dilbits), and establish baseline toxicity data for selected crude oils and dispersant in support of planning and response activities. Abstract reporting the results of EPA's oil and dispersant toxicity testing program
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Stabilization and disposal of Argonne-West low-level mixed wastes in ceramicrete waste forms.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Barber, D. B.; Singh, D.; Strain, R. V.
1998-02-17
The technology of room-temperature-setting phosphate ceramics or Ceramicrete{trademark} technology, developed at Argonne National Laboratory (ANL)-East is being used to treat and dispose of low-level mixed wastes through the Department of Energy complex. During the past year, Ceramicrete{trademark} technology was implemented for field application at ANL-West. Debris wastes were treated and stabilized: (a) Hg-contaminated low-level radioactive crushed light bulbs and (b) low-level radioactive Pb-lined gloves (part of the MWIR {number_sign} AW-W002 waste stream). In addition to hazardous metals, these wastes are contaminated with low-level fission products. Initially, bench-scale waste forms with simulated and actual waste streams were fabricated by acid-base reactionsmore » between mixtures of magnesium oxide powders and an acid phosphate solution, and the wastes. Size reduction of Pb-lined plastic glove waste was accomplished by cryofractionation. The Ceramicrete{trademark} process produces dense, hard ceramic waste forms. Toxicity Characteristic Leaching Procedure (TCLP) results showed excellent stabilization of both Hg and Pb in the waste forms. The principal advantage of this technology is that immobilization of contaminants is the result of both chemical stabilization and subsequent microencapsulation of the reaction products. Based on bench-scale studies, Ceramicrete{trademark} technology has been implemented in the fabrication of 5-gal waste forms at ANL-West. Approximately 35 kg of real waste has been treated. The TCLP is being conducted on the samples from the 5-gal waste forms. It is expected that because the waste forms pass the limits set by the EPAs Universal Treatment Standard, they will be sent to a radioactive-waste disposal facility.« less
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Laporte-Saumure, Mathieu; Martel, Richard; Mercier, Guy
2011-01-01
Backstop soils of four small-arms firing ranges (SAFRs) of the Canadian Force Bases (CFBs) were characterized in terms of their total soil Cu, Pb, Sb and Zn concentrations, grain size distribution, mineralogy, chemical properties, vertical in-depth contamination distribution (for one CFB), and scanning electron microscope (SEM-EDS) characterization. Metal availability from the soils was evaluated with three leaching tests: the toxicity characteristics leaching procedure (TCLP), representing a landfill leachate; the synthetic precipitation leaching procedure (SPLP), representing field conditions; and the gastric juice simulation test (GJST), representing the leachate of the human stomach during the digestive process and, therefore, the potential metal transfer to humans in the case of soil ingestion. Metal analyses of soils and leaching test extracts were conducted with an Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) instrument. Total soil results showed maximal concentrations of 27,100 mg/kg for Pb, 7720 mg/kg for Cu, 1080 mg/kg for Zn, and 570 mg/kg for Sb. The SEM-EDS analysis showed significant amounts of lead carbonates, which resulted from the alteration of the initial metallic Pb particles. Metal availability evaluation with the leaching tests showed that TCLP Pb and Sb thresholds were exceeded. For the SPLP and the GJST, the drinking water thresholds of the Ministère du Développement Durable, de l'Environnement et des Pares (MDDEP) of Quebec were exceeded by Pb and Sb. The metal availability assessment showed that SAFR backstop soils may pose a potential risk to the environment, groundwater and humans, and affect the management of such soils in order to minimize potential metal dispersion in the environment.
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Heavy metal immobilization in soil near abandoned mines using eggshell waste and rapeseed residue.
Lee, Sang Soo; Lim, Jung Eun; El-Azeem, Samy A M Abd; Choi, Bongsu; Oh, Sang-Eun; Moon, Deok Hyun; Ok, Yong Sik
2013-03-01
Heavy metal contamination of agricultural soils has received great concern due to potential risk to human health. Cadmium and Pb are largely released from abandoned or closed mines in Korea, resulting in soil contamination. The objective of this study was to evaluate the effects of eggshell waste in combination with the conventional nitrogen, phosphorous, and potassium fertilizer (also known as NPK fertilizer) or the rapeseed residue on immobilization of Cd and Pb in the rice paddy soil. Cadmium and Pb extractabilities were tested using two methods of (1) the toxicity characteristics leaching procedure (TCLP) and (2) the 0.1 M HCl extraction. With 5 % eggshell addition, the values of soil pH were increased from 6.33 and 6.51 to 8.15 and 8.04 in combination with NPK fertilizer and rapeseed residue, respectively, compared to no eggshell addition. The increase in soil pH may contribute to heavy metal immobilization by altering heavy metals into more stable in soils. Concentrations of TCLP-extracted Cd and Pb were reduced by up to 67.9 and 93.2 % by addition of 5 % eggshell compared to control. For 0.1 M HCl extraction method, the concentration of 0.1 M HCl-Cd in soils treated with NPK fertilizer and rapeseed residue was significantly reduced by up to 34.01 and 46.1 %, respectively, with 5 % eggshell addition compared to control. A decrease in acid phosphatase activity and an increase in alkaline phosphatase activity at high soil pH were also observed. Combined application of eggshell waste and rapeseed residue can be cost-effective and beneficial way to remediate the soil contaminated with heavy metals.
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A comparative assessment of the acute inhalation toxicity of vanadium compounds.
Rajendran, N; Seagrave, J C; Plunkett, L M; MacGregor, J A
2016-11-01
Vanadium compounds have become important in industrial processes, resulting in workplace exposure potential and are present in ambient air as a result of fossil fuel combustion. A series of acute nose-only inhalation toxicity studies was conducted in both rats and mice in order to obtain comparative data on the acute toxicity potential of compounds used commercially. V 2 O 3 , V 2 O 4 , and V 2 O 5 , which have different oxidation states (+3, +4, +5, respectively), were delivered as micronized powders; the highly water-soluble and hygroscopic VOSO 4 (+4) could not be micronized and was instead delivered as a liquid aerosol from an aqueous solution. V 2 O 5 was the most acutely toxic micronized powder in both species. Despite its lower overall percentage vanadium content, a liquid aerosol of VOSO 4 was more toxic than the V 2 O 5 particles in mice, but not in rats. These data suggest that an interaction of characteristics, i.e., bioavailability, solubility and oxidation state, as well as species sensitivity, likely affect the toxicity potential of vanadium compounds. Based on clinical observations and gross necropsy findings, the lung appeared to be the target organ for all compounds. The level of hazard posed will depend on the specific chemical form of the vanadium. Future work to define the inhalation toxicity potential of vanadium compounds of various oxidation states after repeated exposures will be important in understanding how the physico-chemical and biological characteristics of specific vanadium compounds interact to affect toxicity potential and the potential risks posed to human health.
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Fossum, Kenneth D.; O'Day, Christie M.; Wilson, Barbara J.; Monical, Jim E.
2001-01-01
Stormwater and streamflow in Maricopa County were monitored to (1) describe the physical, chemical, and toxicity characteristics of stormwater from areas having different land uses, (2) describe the physical, chemical, and toxicity characteristics of streamflow from areas that receive urban stormwater, and (3) estimate constituent loads in stormwater. Urban stormwater and streamflow had similar ranges in most constituent concentrations. The mean concentration of dissolved solids in urban stormwater was lower than in streamflow from the Salt River and Indian Bend Wash. Urban stormwater, however, had a greater chemical oxygen demand and higher concentrations of most nutrients. Mean seasonal loads and mean annual loads of 11 constituents and volumes of runoff were estimated for municipalities in the metropolitan Phoenix area, Arizona, by adjusting regional regression equations of loads. This adjustment procedure uses the original regional regression equation and additional explanatory variables that were not included in the original equation. The adjusted equations had standard errors that ranged from 161 to 196 percent. The large standard errors of the prediction result from the large variability of the constituent concentration data used in the regression analysis. Adjustment procedures produced unsatisfactory results for nine of the regressions?suspended solids, dissolved solids, total phosphorus, dissolved phosphorus, total recoverable cadmium, total recoverable copper, total recoverable lead, total recoverable zinc, and storm runoff. These equations had no consistent direction of bias and no other additional explanatory variables correlated with the observed loads. A stepwise-multiple regression or a three-variable regression (total storm rainfall, drainage area, and impervious area) and local data were used to develop local regression equations for these nine constituents. These equations had standard errors from 15 to 183 percent.
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Wei, Yunmei; Mei, Xiaoxia; Shi, Dezhi; Liu, Guotao; Li, Li; Shimaoka, Takayuki
2017-06-01
Magnetic fractions were extracted from pulverized waste-to-energy (WTE) bottom ashes using a combined wet-dry extraction method. The resulting magnetic and non-magnetic fractions were subjected to compositional, mineralogical, and redox state analyses by X-ray diffraction (XRD), X-ray fluorescence, and X-ray photoelectron spectroscopy (XPS), respectively. The distribution and leaching toxicity of heavy metals were assessed to evaluate potential effects on the environment. Compositional analyses revealed that Fe accounted for 35% of the magnetic fraction of pulverized ashes, which was approximately seven times that of the raw ash. In addition to Fe, elemental Ni, Mn, and Cr were also significantly enriched in the magnetic fractions. The mineralogical analysis determined that Fe was primarily present as hematite and magnetite, and metallic iron was also identified in the magnetic fraction samples. The XPS analysis further proved the existence of zero-valence Fe. However, a significant amount of Fe remained in the non-magnetic fractions, which could partially be ascribed to the intergrowth structure of the various minerals. The elevated concentrations of toxicity characteristic leaching procedure (TCLP)-extracted Mn, Ni, Cr, Cu, Pb, and Zn were primarily ascribed to the lower buffering capability of the magnetic fractions, with the enrichment of Mn, Ni, and Cr in the magnetic fractions also contributing to this elevation.
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The Use of Modified Bentonite for Removal of Aromatic Organics from Contaminated Soil.
Gitipour; Bowers; Bodocsi
1997-12-15
This study investigates the clay-aromatic interactions with a view to the use of bentonite clay for binding benzene, toluene, ethylbenzene, and o-xylene (BTEX compounds) in contaminated soils. BTEX compounds are the most toxic aromatic constituents of gasoline present in many underground storage tanks. Modified (organophilic) and ordinary bentonites are used to remove these organics. The organophilic bentonites are prepared by replacing the exchangeable inorganic cations present in bentonite particles with a quaternary ammonium salt. Various clay-to-soil ratios were applied to determine the efficiency of the modified bentonite in enhancing the cement-based solidification/stabilization (S/S) of BTEX contaminated soils. Toxicity characteristics leaching procedure (TCLP) tests were performed on soil samples to evaluate the leaching of the organics. In addition, X-ray diffraction analyses were conducted to assess the changes in the basal spacing of the clays as a result of their interaction with BTEX compounds. The findings of this study reveal that organophilic bentonite can act as a successful adsorbent for removing the aromatic organics from contaminated soil. Thus, this material is viable for enhancing the performance of cement-based S/S processes, as an adsorbent for petroleum spills, and for landfill liners and slurry walls. Copyright 1997 Academic Press.
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Antibacterial properties and toxicity from metallic nanomaterials
Vimbela, Gina V; Ngo, Sang M; Fraze, Carolyn; Yang, Lei; Stout, David A
2017-01-01
The era of antibiotic resistance is a cause of increasing concern as bacteria continue to develop adaptive countermeasures against current antibiotics at an alarming rate. In recent years, studies have reported nanoparticles as a promising alternative to antibacterial reagents because of their exhibited antibacterial activity in several biomedical applications, including drug and gene delivery, tissue engineering, and imaging. Moreover, nanomaterial research has led to reports of a possible relationship between the morphological characteristics of a nanomaterial and the magnitude of its delivered toxicity. However, conventional synthesis of nanoparticles requires harsh chemicals and costly energy consumption. Additionally, the exact relationship between toxicity and morphology of nanomaterials has not been well established. Here, we review the recent advancements in synthesis techniques for silver, gold, copper, titanium, zinc oxide, and magnesium oxide nanomaterials and composites, with a focus on the toxicity exhibited by nanomaterials of multidimensions. This article highlights the benefits of selecting each material or metal-based composite for certain applications while also addressing possible setbacks and the toxic effects of the nanomaterials on the environment. PMID:28579779
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Dosimetric characteristics of PASSAG as a new polymer gel dosimeter with negligible toxicity
NASA Astrophysics Data System (ADS)
Farhood, Bagher; Abtahi, Seyed Mohammad Mahdi; Geraily, Ghazale; Ghorbani, Mehdi; Mahdavi, Seied Rabi; Zahmatkesh, Mohammad Hasan
2018-06-01
Despite many advantages of polymer gel dosimeters, their clinical use is only not realized now. Toxicity of polymer gel dosimeters can be considered as one of their main limitations for use in routine clinical applications. In the current study, a new polymer gel dosimeter is introduced with negligible toxicity. For this purpose, 2-Acrylamido-2-Methy-1-PropaneSulfonic acid (AMPS) sodium salt monomer was replaced instead of acrylamide monomer used in PAGAT gel dosimeter by using %6 T and %50 C to the gel formula and the new formulation is called PASSAG (Poly AMPS Sodium Salt and Gelatin) polymer gel dosimeter. The irradiation of gel dosimeters was carried out using a Co-60 therapy machine. MRI technique was used to quantify the dose responses of the PASSAG gel dosimeter. Then, the MRI responses (R2) of the gel dosimeter was analyzed at different dose values, post-irradiation times, and scanning temperatures. The results showed that the new gel formulation has a negligible toxicity and it is also eco-friendly. In addition, carcinogenicity and genetic toxicity tests are negative for the monomer used in PASSAG. The radiological properties of PASSAG gel dosimeter showed that this substance can be considered as a soft tissue/water equivalent material. Furthermore, dosimetric evaluation of the new polymer gel dosimeter revealed an excellent linear R2-dose response in the evaluated dose range (0-15 Gy). The R2-dose sensitivity and dose resolution of PASSAG gel dosimeter were 0.081 s-1Gy-1 (in 0-15 Gy dose range) and 1 Gy (in 0-10 Gy dose range), respectively. Moreover, it was shown that the R2-dose sensitivity and dose resolution of the new gel dosimeter improves over time after irradiation. It was also found that the R2 response of the PASSAG gel dosimeter has less dependency to the 18, 20, and 24 °C scanning temperature in comparison to that of room temperature (22 °C).
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Khoja, Leila; Atenafu, Eshetu G; Ye, Qian; Gedye, Craig; Chappell, Maryanne; Hogg, David; Butler, Marcus O; Joshua, Anthony M
2016-02-01
Approved by the Food and Drug Administration in 2011, the anti-cytotoxic T-lymphocyte-associated protein 4 checkpoint inhibitor ipilimumab has delivered a survival benefit of ≥3 years in a subset of metastatic melanoma patients. After participating in the registration trial, patients were treated with this agent in routine practice. Toxicity and efficacy of agents in "real world" settings may differ from trials. The present study aimed to evaluate, with respect to toxicity and outcome, all patients treated with ipilimumab to date at the Princess Margaret Hospital (Toronto, Canada). Patients treated with ipilimumab between 2008 and 2013 were identified, and patient characteristics (age, gender, tumour burden, oncogenic mutation status, number of treatments received and toxicities from treatment) were collected. Progression-free survival (PFS) and overall survival (OS) were calculated from the commencement of ipilimumab treatment. Associations between clinical characteristics and outcome or toxicity were assessed. Between 2008 and 2013, 129 patients with metastatic cutaneous melanoma were treated. Since, during this period, ipilimumab was approved in the second line setting, ipilimumab was delivered in the second or subsequent line in all patients, and 70% did not receive any further anticancer therapy. Immune-related toxicities were observed, the onset of which varied from 1 to 162 days. The majority resolved within 6 weeks of the final treatment, with the exception of endocrinopathies and bowel related toxicity. The median PFS and OS were 2.83 and 8.44 months, respectively. No pre-treatment factor independently predicted toxicity. The number of infusions (4 vs. ≤3) and presence of toxicity were significantly associated with superior survival. The onset of toxicity secondary to ipilimumab could occur later than previously reported. Toxicities were manageable, but required long-term vigilance.
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Zhang, Hui-Hui; Li, Zheng; Liu, Yu; Xinag, Ping; Cui, Xin-Yi; Ye, Hui; Hu, Bao-Lan; Lou, Li-Ping
With the increasing occurrence of haze during the summer, the physicochemical characteristics and toxicity differences in PM 2.5 in different seasons are of great concern. Hangzhou is located in an area that has a subtropical monsoon climate where the humidity is very high during both the summer and winter. However, there are limited studies on the seasonal differences in PM 2.5 in these weather conditions. In this test, PM 2.5 samples were collected in the winter and summer, the morphology and chemical composition of PM 2.5 were analyzed, the toxicity of PM 2.5 to human bronchial cells BEAS-2B was compared, and the correlation between PM 2.5 toxicity and the chemical composition was discussed. The results showed that during both the winter and summer, the main compounds in the PM 2.5 samples were water-soluble ions, particularly SO 4 2- , NO 3 - , and NH 4 + , followed by organic components, while heavy metals were present at lower levels. The higher the mass concentration of PM 2.5 , the greater its impact on cell viability and ROS levels. However, when the mass concentration of PM 2.5 was similar, the water extraction from the summer samples showed a greater impact on BEAS-2B than that from the winter samples. The cytotoxicity of PM 2.5 was closely associated with heavy metals and organic pollutants but less related to water-soluble ions.
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Landfill Leachate Toxicity Removal in Combined Treatment with Municipal Wastewater
Kalka, J.
2012-01-01
Combined treatment of landfill leachate and municipal wastewater was performed in order to investigate the changes of leachate toxicity during biological treatment. Three laboratory A2O lab-scale reactors were operating under the same parameters (Q-8.5–10 L/d; HRT-1.4–1.6 d; MLSS 1.6–2.5 g/L) except for the influent characteristic and load. The influent of reactor I consisted of municipal wastewater amended with leachate from postclosure landfill; influent of reactor II consisted of leachate collected from transient landfill and municipal wastewater; reactor III served as a control and its influent consisted of municipal wastewater only. Toxicity of raw and treated wastewater was determinted by four acute toxicity tests with Daphnia magna, Thamnocephalus platyurus, Vibrio fischeri, and Raphidocelis subcapitata. Landfill leachate increased initial toxicity of wastewater. During biological treatment, significant decline of acute toxicity was observed, but still mixture of leachate and wastewater was harmful to all tested organisms. PMID:22623882
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Ducrot, Virginie; Usseglio-Polatera, Philippe; Péry, T Alexandre R R; Mouthon, Jacques; Lafont, Michel; Roger, Marie-Claude; Garric, Jeanne; Férard, Jean-François
2005-09-01
An original species-selection method for the building of test batteries is presented. This method is based on the statistical analysis of the biological and ecological trait patterns of species. It has been applied to build a macroinvertebrate test battery for the assessment of sediment toxicity, which efficiently describes the diversity of benthic macroinvertebrate biological responses to toxicants in a large European lowland river. First, 109 potential representatives of benthic communities of European lowland rivers were selected from a list of 479 taxa, considering 11 biological traits accounting for the main routes of exposure to a sediment-bound toxicant and eight ecological traits providing an adequate description of habitat characteristics used by the taxa. Second, their biological and ecological trait patterns were compared using coinertia analysis. This comparison allowed the clustering of taxa into groups of organisms that exhibited similar life-history characteristics, physiological and behavioral features, and similar habitat use. Groups exhibited various sizes (7-35 taxa), taxonomic compositions, and biological and ecological features. Main differences among group characteristics concerned morphology, substrate preferendum and habitat utilization, nutritional features, maximal size, and life-history strategy. Third, the best representatives of the mean biological and ecological characteristics of each group were included in the test battery. The final selection was composed of Chironomus riparius (Insecta: Diptera), Branchiura sowerbyi (Oligochaeta: Tubificidae), Lumbriculus variegatus (Oligochaeta: Lumbriculidae), Valvata piscinalis (Gastropoda: Valvatidae), and Sericostoma personatum (Trichoptera: Sericostomatidae). This approach permitted the biological and ecological variety of the battery to be maximized. Because biological and ecological traits of taxa determine species sensitivity, such maximization should permit the battery to better account
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Toxicity evaluation of the process effluent streams of a petrochemical industry.
Reis, J L R; Dezotti, M; Sant'Anna, G L
2007-02-01
The physico-chemical characteristics and the acute toxicity of several wastewater streams, generated in the industrial production of synthetic rubber, were determined. The acute toxicity was evaluated in bioassays using different organisms: Danio rerio (fish), Lactuca sativa (lettuce) and Brachionus calyciflorus (rotifer). The removal of toxicity attained in the industrial wastewater treatment plant was also determined upstream and downstream of the activated sludge process. The results obtained indicate that the critical streams in terms of acute toxicity are the effluents from the liquid polymer unit and the spent caustic butadiene washing stage. The biological treatment was able to partially remove the toxicity of the industrial wastewater. However, a residual toxicity level persisted in the biotreated wastewater. The results obtained with Lactuca sativa showed a high degree of reproducibility, using root length or germination index as evaluation parameters. The effect of volatile pollutants on the toxicity results obtained with lettuce seeds was assessed, using ethanol as a model compound. Modifications on the assay procedure were proposed. A strong correlation between the toxic responses of Lactuca sativa and Danio rerio was observed for most industrial effluent streams.
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Irizar, A; Rodríguez, M P; Izquierdo, A; Cancio, I; Marigómez, I; Soto, M
2015-01-01
Bioavailability is affected by soil physicochemical characteristics such as pH and organic matter (OM) content. In addition, OM constitutes the energy source of Eisenia fetida, a well established model species for soil toxicity assessment. The present work aimed at assessing the effects of changes in OM content on the toxicity of Cd in E. fetida through the measurement of neutral red uptake (NRU) and mortality, growth, and reproduction (Organisation for Economic Co-operation and Development [OECD] Nos. 207 and 222). Complementarily, metallothionein (MT) and catalase transcription levels were measured. To decrease variability inherent to natural soils, artificial soils (Organization for Economic Cooperation and Development 1984) with different OM content (6, 10, and 14%) and spiked with Cd solutions at increasing concentrations were used. Low OM in soil decreased soil ingestion and Cd bioaccumulation but also increased Cd toxicity causing lower NRU of coelomocytes, 100 % mortality, and stronger reproduction impairment, probably due to the lack of energy to maintain protection mechanisms (production of MT).Cd bioaccumulation did not reflect toxicity, and OM played a pivotal role in Cd toxicity. Thus, OM content should be taken into account when using E. fetida in in vivo exposures for soil health assessment.
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Gong, Bing; Deng, Yi; Yang, Yuanyi; Tan, Swee Ngin; Liu, Qianni; Yang, Weizhong
2017-01-01
In the present work, thermal treatment was used to stabilize municipal solid waste incineration (MSWI) fly ash, which was considered hazardous waste. Toxicity characteristic leaching procedure (TCLP) results indicated that, after the thermal process, the leaching concentrations of Pb, Cu, and Zn decreased from 8.08 to 0.16 mg/L, 0.12 to 0.017 mg/L and 0.39 to 0.1 mg/L, respectively, which well met the limits in GB5085.3-2007 and GB16689-2008. Thermal treatment showed a negative effect on the leachability of Cr with concentrations increasing from 0.1 to 1.28 mg/L; nevertheless, it was still under the limitations. XRD analysis suggested that, after thermal treatments, CaO was newly generated. CaO was a main contribution to higher Cr leaching concentrations owing to the formation of Cr (VI)—compounds such as CaCrO4. SEM/EDS tests revealed that particle adhesion, agglomeration, and grain growth happened during the thermal process and thus diminished the leachability of Pb, Cu, and Zn, but these processes had no significant influence on the leaching of Cr. A microbial assay demonstrated that all thermally treated samples yet possessed strong bactericidal activity according to optical density (OD) test results. Among all samples, the OD value of raw fly ash (RFA) was lowest followed by FA700-10, FA900-10, and FA1100-10 in an increasing order, which indicated that the sequence of the biotoxicity for these samples was RFA > FA700-10 > FA900-10 > FA1100-10. This preliminary study indicated that, apart from TCLP criteria, the biotoxicity assessment was indispensable for evaluating the effect of thermal treatment for MSWI fly ash. PMID:28604580
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Zhao, Ling; Ding, Zhenliang; Sima, Jingke; Xu, Xiaoyun; Cao, Xinde
2017-09-01
This study aims to develop an amendment for simultaneous immobilization of Zn and Cr(VI) in an abandoned electroplating contaminated soil. Nature phosphate rock was first activated with oxalic acid (O-PR) and then combined with FeSO 4 or zero-valent iron (ZVI) for immobilization of Zn and Cr(VI) from aqueous solutions. Finally, the optimized approach showing the highest immobilization ability in solution was applied in an electroplating contaminated soil. The O-PR combined with FeSO 4 was more effective in simultaneously removing Zn and Cr(VI) than the O-PR integrated with ZVI within the tested solution pH range of 5.5-8.5. Both O-PR with FeSO 4 and with ZVI removed over 95% of Zn from the solution; however, only 42-46% of Cr(VI) was immobilized by O-PR with ZVI, while O-PR with FeSO 4 almost precipitated all Cr(VI). Moreover, there were 75-95% Zn and 95-100% Cr(VI) remaining in the exhausted O-PR with FeSO 4 solid after toxicity characteristic leaching test (TCLP) while the exhausted O-PR with ZVI solid only retained 44-83% Zn and 32-72% Cr(VI). Zinc was immobilized mainly via formation of insoluble Fe-Zn phosphate co-precipitates, while iron-induced reduction of Cr(VI) into stable Cr(OH) 3 or Cr x Fe (1-x) (OH) 3 was responsible for Cr(VI) immobilization. Application of the O-PR integrated with FeSO 4 in the electroplating contaminated soil rapidly reduced the TCLP extractable Zn and Cr(VI) to below the standard limits, with decrease by 50% and 94%, respectively. This study revealed that combination of oxalic acid activated phosphate rock with FeSO 4 could be an effective amendment for remediation of Zn and Cr(VI) contaminated soil. Copyright © 2017 Elsevier Ltd. All rights reserved.
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The As removal from arsenopyrite-bearing mine waste by microwave
NASA Astrophysics Data System (ADS)
Kim, Hyun Soo; Myung, Eun Ji; Hack Lim, Dae; Kim, Bong Ju; Park, Cheon Young
2016-04-01
Penalties incurred by miners for arsenic in concentrates have increased significantly because the removal and disposal of arsenic is difficult and costly for smelters and because the environmental challenges are increasing worldwide. Typically miners incur penalties on arsenic in concentrates above 0.2% As with smelter rejection limits of 0.5%. Therefore, finding an effective solution for removing As during primary mining activities is necessary to avoid penalty. The aim of this study was to investigate the As removal from mine waste using microwave process. The mine waste samples were characterized by chemical and XRD analysis. To determine of As removal from the microwave experiments, aqua regia digestion was performed according to Korean environmental standard method(KESM) and the As removal effect were evaluated using the standard EPA toxicity characteristic leaching procedure(TCLP, EPA 1311 method). The result of mineralogical character for mine waste using XRD was detected arsenopyrite, pyrite, chalcopyrite, pyrrhotite and quartz. The chemical analysis of As, Pb, Zn contents in the mine waste measured 13,896.0, 896.1 and 1,054.6 mg/kg, respectively. The As removal of experiments was conducted to examine the effects of microwave exposure time(1~15min). The results showed that the As removal in mine waste (exposure time = 10min) was 92.90%, and the temperature of mine waste by microwave heating was 886℃. The TCLP leaching of treated mine waste by microwave measured values were below the EPA's current regulatory threshold(As, Pb, Zn : 5 mg/L). The optimum condition of microwave exposure for As removal from arsenopyrite-bearing mine waste was obtained at 800W, 2450MHz, 10min. Acknowledgment : This work was supported by the Energy and Resources Engineering Program Grant funded by the Ministry of Trade, Industry and Energy, Korea
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Volland, Moritz; Hampel, Miriam; Katsumiti, Alberto; Yeste, María Pilar; Gatica, José Manuel; Cajaraville, Miren; Blasco, Julián
2018-06-01
Copper oxide (CuO) nanoparticles (NPs) are increasingly investigated, developed and produced for a wide range of industrial and consumer products. Notwithstanding their promising novel applications, concern has been raised that their increased use and disposal could consequently increase their release into marine systems and potentially affect species within. To date the understanding of factors and mechanisms of CuO (nano-) toxicity to marine invertebrates is still limited. Hence, we studied the characteristics and behaviour of two commercially available CuO NPs of similar size, but produced employing distinct synthesis methods, under various environmentally and experimentally relevant conditions. In addition, cell viability and DNA damage, as well as gene expression of detoxification, oxidative stress, inflammatory response, DNA damage repair and cell death mediator markers were studied in primary cultures of hemocytes from the marine clam Ruditapes philippinarum and, where applicable, compared to bulk CuO and ionic Cu (as CuSO 4 ) behaviour and effects. We found that the synthesis method can influence particle characteristics and behaviour, as well as the toxicity of CuO NPs to Ruditapes philippinarum hemocytes. Our results further indicate that under the tested conditions aggregating behaviour influences the toxicity of CuO NPs by influencing their rate of extra- and intracellular dissolution. In addition, gene expression analysis identified similar transcriptional de-regulation for all tested copper treatments for the here measured suite of genes. Finally, our work highlights various differences in the aggregation and dissolution kinetics of CuO particles under environmental (marine) and cell culture exposure conditions that need consideration when extrapolating in vitro findings. Copyright © 2018 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Losso, C.; Arizzi Novelli, A.; Picone, M.; Marchetto, D.; Pessa, G.; Molinaroli, E.; Ghetti, P. F.; Volpi Ghirardini, A.
2004-11-01
Toxic hazard in sites with varying types and levels of contamination in the Lagoon of Venice was estimated by means of toxicity bioassays based on the early life-stages of the autochthonous sea urchin Paracentrotus lividus. Elutriate was chosen as the test matrix, due to its ability to highlight potential toxic effects towards sensitive biological components of the water column caused by sediment resuspension phenomena affecting the Lagoon. Surficial sediments (core-top 5 cm deep), directly influenced by resuspension/redeposition processes, and core sediments (core 20 cm deep), recording time-mediated contamination, were sampled in some sites located in the lagoonal area most greatly influenced by anthropogenic activities. Particle size, organic matter and water content were also analysed. In two sites, the results of physical parameters showed that the core-top sediments were coarser than the 20-cm core sediments. Sperm cell toxicity test results showed the negligible acute toxicity of elutriates from all investigated sites. The embryo toxicity test demonstrated a short-term chronic toxicity gradient for elutriates from the 20-cm core sediments, in general agreement both with the expected contamination gradient and with results of the Microtox® solid-phase test. Elutriates of the core-top 5-cm sediments revealed a totally inverted gradient, in comparison with that for the 20-cm core sediments, and the presence of a "hot spot" of contamination in the site chosen as a possible reference. Investigations on ammonia and sulphides as possible confounding factors excluded their contribution to this "hot spot". Integrated physico-chemical and toxicity results on sediments at various depths demonstrated the presence of disturbed sediments in the central basin of the Lagoon of Venice.
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Rodríguez-Nuñez, Antonio; Dosil-Gallardo, Silvia; Jordan, Iolanda
2011-05-01
Streptococcal toxic shock syndrome (STSS) is a very rare and severe form of group A streptococcal infection whose clinical characteristics, therapy, morbidity, and mortality in children are not well known. Our objective was to describe the clinical characteristics of STSS in a series of children admitted to pediatric intensive care units (PICU). A multicenter, retrospective study of children with STSS admitted to 14 PICUs between January 1998 and December 2009 was conducted. Clinical information was obtained retrospectively by chart review. Data from 41 children were collected, 90% corresponding to the second half of the study period. Initial symptoms and signs were nonspecific. All patients developed shock and organ dysfunction, 78.0% developed coagulopathy, 70.7% neurologic dysfunction, and 68.3% respiratory failure. Rapid pharyngeal test for Streptococcus was positive in 78.0%. Initial leukocyte count was quite variable, with leukopenia present in 51.2% of patients and leukocytosis in 31.7%. Children were treated with antibiotics against group A Streptococcus (GAS), usually G penicillin or cephalosporin plus clindamycin. After a median PICU stay of 7 days (range 0-41), 65.8% of patients survived, 26.8% with sequelae. The cause of death of the 11 non-survivors was refractory shock and multi-organ failure. STSS is a very severe condition secondary to invasive GAS infection. It can occur at any age, but especially in young children. Due to the lack of specific symptoms and signs and its very rapid progression to shock and organ dysfunction, pediatricians and emergency physicians must be aware of this possibility and immediately initiate aggressive treatment when suspected.
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Wang, Shengsen; Gao, Bin; Li, Yuncong; Ok, Yong Sik; Shen, Chaofeng; Xue, Shengguo
2017-07-01
In this work, an innovative approach using biochar technology for hyperaccumulator disposal was developed and evaluated. The heavy metal enriched P. acinosa biomass (PBM) was pyrolyzed to produce biochar (PBC). Both PBM and PBC were characterized with X-ray diffraction (XRD) for crystal phases, scanning electron microscopy (SEM) for surface topography, and analyzed for elemental composition and mobility. The results revealed that whewellite, a dominant crystal form in biomass, was decomposed to calcite after pyrolysis. Elemental analysis indicated that 91-99% total non-volatile elements in the biomass were retained in the biochar. The toxicity characteristic leaching procedure (TCLP) results revealed that 94.6% and 0.15% of total Mn was extracted for biomass and biochar, respectively. This suggests that mobility and bioavailability of Mn in biochar was much lower relative to pristine biomass. Batch sorption experiment showed that excellent removal of aqueous silver, lead, cadmium, and copper ions can be achieved with PBC. Findings from this work indicated that biochar technology can provide a value-added solution for hyperaccumulator disposal. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Zhang, Runyuan; Zhang, Nuanqin; Fang, Zhanqiang
2018-03-01
In this study, the remediation experiments were performed outdoors in natural conditions. Carboxymethyl cellulose (CMC)-stabilized nanoscale zero-valent iron (CMC-nZVI), biochar (BC) and CMC-stabilized nanoscale zero-valent iron composited with biochar (CMC-nZVI/BC) were synthesized and investigated for their effect on the in situ remediation of hexavalent chromium [Cr(VI)] contaminated soil and the concentration of available iron was tested after the remediation, compared with the untreated soil. The results of toxicity characteristic leaching procedure (TCLP) test showed that CMC-nZVI and CMC-nZVI/BC used as remediation materials could obviously improve the remediation rate of Cr contaminated soil and when the ratio of CMC-nZVI to Fe 0 was 2.5 g/Kg, the leachability of Cr(VI) and Cr total can be reduced by 100% and 95.8% simultaneously. Moreover, sequential extraction procedure (SEP) showed that most exchangeable Cr converted to carbonate-bound and Fe-Mn oxides-bound, reducing the availability and leachability of Cr in the soil.
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Coruh, Semra; Ergun, Osman Nuri
2010-01-15
Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The release of large quantities of heavy metals into the environment has resulted in a number of environmental problems. The present study investigated the safe disposal of the zinc leach residue waste using industrial residues such as fly ash, phosphogypsum and red mud. In the study, leachability of heavy metals from the zinc leach residue has been evaluated by mine water leaching procedure (MWLP) and toxicity characteristic leaching procedure (TCLP). Zinc removal from leachate was studied using fly ash, phosphogypsum and red mud. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudo-second-order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudo-second-order kinetic was the best fit kinetic model for the experimental data. The results show that addition of fly ash, phosphogypsum and red mud to the zinc leach residue drastically reduces the heavy metal content in the leachate and could be used as liner materials.
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Leachability of fired clay brick incorporating with sewage sludge waste
NASA Astrophysics Data System (ADS)
Kadir, Aeslina Abdul; Salim, Nurul Salhana Abdul; Sarani, Noor Amira; Rahmat, Nur Aqma Izurin; Abdullah, Mohd Mustafa Al Bakri
2017-09-01
Sewage sludge is sewerage from wastewater treatment plants that generates millions tons of sludge ever year. Regarding this activity, it causes lack management of waste which is harmful to the surrounding conditions. Therefore, this study is focuses on the incorporation of sewage sludge waste into fired clay brick to provide an option of disposal method, producing adequate quality of brick as well as limiting the heavy metal leachability to the environment. Sewage sludge brick (SSB) mixtures were incorporated with 0%, 1%, 5%, 10%, 20% and 30% of sewage sludge waste (SSW). Heavy metals of crushed SSB were determined by using Toxicity Characteristic Leaching Procedure (TCLP) according to Method 1311 of United State Environment Protection Agency (USEPA) standard. From the results obtained, up to 20% of SSW could be incorporated into fired clay brick and comply with the USEPA standard. Therefore, this study revealed that by incorporating SSW into fired clay brick it could be an alternative method to dispose the SSW and also could act as a replacement material for brick manufacturing with appropriate mix and design.
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Shan, Jilei; Sáez, A. Eduardo; Ela, Wendell P.
2013-01-01
Many water treatment technologies for arsenic removal that are used today produce arsenic-bearing residuals which are disposed in non-hazardous landfills. Previous works have established that many of these residuals will release arsenic to a much greater extent than predicted by standard regulatory leaching tests (e.g. the toxicity characteristic leaching procedure, TCLP) and, consequently, require stabilization to ensure benign behavior after disposal. In this work, a four-step sequential extraction method was developed in an effort to determine the proportion of arsenic in various phases in untreated as well as stabilized iron-based solid matrices. The solids synthesized using various potential stabilization techniques included: amorphous arsenic-iron sludge (ASL), reduced ASL via reaction with zero valent iron (RASL), amorphous ferrous arsenate (PFA), a mixture of PFA and SL (M1), crystalline ferrous arsenate (HPFA), and a mixture of HPFA and SL (M2). The overall arsenic mobility of the tested samples increased in the following order: ASL > RASL > PFA > M1 > HPFA > M2. PMID:23459695
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Shih, Kaimin
2012-12-01
This study investigates potential solid-state reactions for the stabilization of hazardous metals when reusing the incineration ash from chemically enhanced primary treatment (CEPT) sludge to fabricate ceramic products. Nickel and copper were used as examples of hazardous metals, and the iron content in the reaction system was found to play a major role in incorporating these hazardous metals into their ferrite phases (NiFe2O4 and CuFe2O4). The results from three-hour sintering experiments on NiO + Fe2O3 and CuO + Fe2O3 systems clearly demonstrate the potential for initiating metal incorporation mechanisms using an iron-containing precursor at attainable ceramic sintering temperatures (above 750 degrees C). Both ferrite phases were examined using a prolonged leaching experiment modified from the widely used toxicity characteristic leaching procedure (TCLP) to evaluate their long-term metal leachability. The leaching results indicate that both the NiFe2O4 and the CuFe2O4 products were significantly superior to their oxide forms in immobilizing hazardous metals.
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Assessment of Cost Impacts of Using Non-Toxic Propulsion in Satellites
NASA Astrophysics Data System (ADS)
Schiebener, P. J.; Gies, O.; Stuhlberger, J.; Schmitz, H.-D.
2002-01-01
The growing costs of space missions, the need for increased mission performance, and concerns associated with environmental issues deeply influence propulsion system design and propellant selection criteria. A propellant's performance was defined in the past exclusively in terms of specific impulse and density, but now high-performance, non-toxic, non-sophisticated mono- propellant systems are key drivers, and are considered for development to replace the traditional hydrazine (N2H4) mono-propellant thrusters. The mono-propellants under consideration are propellant formulations, which should be environmentally friendly, should have a high density, equal or better performance and better thermal characteristics than hydrazine. These considerations raised interest specially in the candidates of Hydroxylammonium Nitrate (HAN)-based propellants, Ammoniumdinitramide (ADN)-based propellants, Tri-ethanol (TEAN)-based propellants, Hydrazinium Nitroformate (HNF)-based propellants, Hydrogen Peroxide (H2O2)-based propellants. A near-term objective in consideration of satellite related process optimisation is to significantly reduce on-ground operations costs and at the same time improve mission performance. A far-term objective is to obtain a system presenting a very high performance, illustrated by a high specific impulse. Moving to a "non-toxic" propulsion system seems to be a solution to these two goals. The sought after benefits for non-toxic spacecraft mono-propellant propulsion are under investigation taking into account the four main parameters which are mandatory for customer satisfaction while meeting the price constraints: - Reliability, availability, maintainability and safety, - Manufacturing, assembly, integration and test, - Launch preparation and support, - Ground support equipment. These benefits of non-toxic mono-propellants can be proven by various examples, like an expected reduction of development costs due the non-toxicity of propellants which might allow
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Haloacetonitriles: metabolism and toxicity.
Lipscomb, John C; El-Demerdash, Ebtehal; Ahmed, Ahmed E
2009-01-01
bioactivation process, depending on the particular HAN and the enzyme involved. HANs can inhibit CYP2E1-mediated metabolism, an effect which may be dependent on a covalent interaction with the enzyme. In addition, HAN compounds inhibit GST-mediated conjugation, but this effect is reversible upon dialysis, indicating that the interaction does not represent covalent binding. No subchronic studies of HAN toxicity are available in the literature. However, studies show that HANs produce developmental toxicity in experimental animals. The nature of developmental toxicity is affected by the type of administration vehicle, which renders interpretation of results more difficult. Skin tumors have been found following dermal application of HANs, but oral studies for carcinogenicity are negative. Pulmonary adenomas were increased following oral administration of HANs, but the A/J strain of mice employed has a characteristically high background rate of such tumors. HANs interact with DNA to produce unscheduled DNA repair, SCE and reverse mutations in Salmonella. HANs did not induce micronuclei or cause alterations in sperm head morphology in mice, but did induce micronuclei in newts. Thus, there is concern for the potential carcinogenicity of HANs. It would be valuable to delineate any relationship between the apparent threshold for micronuclei formation in newts and the potential mechanism of toxicity involving HAN-induced oxidative stress. Dose-response studies in rodents may provide useful information on toxicity mechanisms and dose selection for longer term toxicity studies. Additional studies are warranted before drawing firm conclusions on the hazards of HAN exposure. Moreover, additional studies on HAN-DNA and HAN-protein interaction mechanisms, are needed. Such studies can better characterize the role of metabolism in toxicity of individual HANs, and delineate the role of oxidative stress, both of which enhance the capacity to predict risk. Most needed, now, are new subchronic (and
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Hazardous and toxic waste management in Botswana: practices and challenges.
Mmereki, Daniel; Li, Baizhan; Meng, Liu
2014-12-01
Hazardous and toxic waste is a complex waste category because of its inherent chemical and physical characteristics. It demands for environmentally sound technologies and know-how as well as clean technologies that simultaneously manage and dispose it in an environmentally friendly way. Nevertheless, Botswana lacks a system covering all the critical steps from importation to final disposal or processing of hazardous and toxic waste owing to limited follow-up of the sources and types of hazardous and toxic waste, lack of modern and specialised treatment/disposal facilities, technical know-how, technically skilled manpower, funds and capabilities of local institutions to take lead in waste management. Therefore, because of a lack of an integrated system, there are challenges such as lack of cooperation among all the stakeholders about the safe management of hazardous and toxic waste. Furthermore, Botswana does not have a systematic regulatory framework regarding monitoring and hazardous and toxic waste management. In addition to the absence of a systematic regulatory framework, inadequate public awareness and dissemination of information about hazardous and toxic waste management, slower progress to phase-out persistent and bio-accumulative waste, and lack of reliable and accurate information on hazardous and toxic waste generation, sources and composition have caused critical challenges to effective hazardous and toxic waste management. It is, therefore, important to examine the status of hazardous and toxic waste as a waste stream in Botswana. By default; this mini-review article presents an overview of the current status of hazardous and toxic waste management and introduces the main challenges in hazardous and toxic waste management. Moreover, the article proposes the best applicable strategies to achieve effective hazardous and toxic waste management in the future. © The Author(s) 2014.
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Kim, Jae Woo
2012-01-01
This article schematically reviews the clinical features, diagnostic approaches to, and toxicological implications of toxic encephalopathy. The review will focus on the most significant occupational causes of toxic encephalopathy. Chronic toxic encephalopathy, cerebellar syndrome, parkinsonism, and vascular encephalopathy are commonly encountered clinical syndromes of toxic encephalopathy. Few neurotoxins cause patients to present with pathognomonic neurological syndromes. The symptoms and signs of toxic encephalopathy may be mimicked by many psychiatric, metabolic, inflammatory, neoplastic, and degenerative diseases of the nervous system. Thus, the importance of good history-taking that considers exposure and a comprehensive neurological examination cannot be overemphasized in the diagnosis of toxic encephalopathy. Neuropsychological testing and neuroimaging typically play ancillary roles. The recognition of toxic encephalopathy is important because the correct diagnosis of occupational disease can prevent others (e.g., workers at the same worksite) from further harm by reducing their exposure to the toxin, and also often provides some indication of prognosis. Physicians must therefore be aware of the typical signs and symptoms of toxic encephalopathy, and close collaborations between neurologists and occupational physicians are needed to determine whether neurological disorders are related to occupational neurotoxin exposure. PMID:23251840
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The effect of olanzapine pretreatment on acute cocaine toxicity in mice.
Heard, Kennon J; Cleveland, Nathan R; Krier, Shay
2009-07-01
Acute cocaine poisoning causes neuroexcitation and can be fatal. The toxic effects of cocaine can be attenuated by antagonists of serotonin, muscarinic cholinergic, and dopamine receptors. Olanzapine, an atypical antipsychotic medication, is an antagonist of these receptors. The objective of this study is to evaluate the efficacy of olanzapine pretreatment for attenuation of acute cocaine toxicity using a mouse model. Eighty male CF-1 mice were randomly assigned to olanzapine (1 mg/kg) or placebo pretreatment. Fifteen minutes later, all animals received 103 mg/kg intraperitoneal cocaine. Overall mortality was 11% for olanzapine-treated animals and 45% for placebo. Olanzapine also appeared to alter the characteristics of seizures due to cocaine. In this model of acute cocaine toxicity, olanzapine pretreatment attenuated acute cocaine toxicity. Olanzapine should be evaluated further as a potential treatment for acute cocaine poisoning.
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40 CFR 268.34 - Waste specific prohibitions-toxicity characteristic metal wastes.
Code of Federal Regulations, 2011 CFR
2011-07-01
... characteristic wastes from elemental phosphorus processing; radioactive wastes mixed with EPA Hazardous wastes... identified characteristic wastes from elemental phosphorus processing, radioactive waste mixed with D004-D011...
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40 CFR 268.34 - Waste specific prohibitions-toxicity characteristic metal wastes.
Code of Federal Regulations, 2010 CFR
2010-07-01
... characteristic wastes from elemental phosphorus processing; radioactive wastes mixed with EPA Hazardous wastes... identified characteristic wastes from elemental phosphorus processing, radioactive waste mixed with D004-D011...
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A CONTROLLED BIOASSAY SYSTEM FOR MEASURING TOXICITY OF HEAVY METALS
Biological availability of metal micronutrients and metal toxicity are believed to be dependent on metal oxidation state, complexation, and solubility as well as the physicochemical characteristics of the aqueous phase. Basic design criteria for fish bioassays which are capable o...
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Sawyer, Thomas W; McNeely, Karin; Louis, Kristen; Lecavalier, Pierre; Song, Yanfeng; Villanueva, Mercy; Clewley, Robin
2017-05-01
Sulphur mustard (bis(2-chloroethyl) sulphide; agent H) is a vesicant chemical warfare (CW) agent whose mechanism of action is not known with any certainty and for which there are no effective antidotes. It has a pronounced latent period before signs and symptoms of poisoning appear which it shares with the nitrogen mustards, and that differentiates it from other classes of vesicant agents. Sulphur mustard, the sulphur mustard CW agents Q (1,2-bis(2-chloroethylthio) ethane) and T (1,1 bis(2-chloroethylthioethyl) ether), the H partial hydrolysis product hemi-sulphur mustard (2-chloroethyl 2-hydroxyethyl sulphide; HSM), and the commercially available 2-chloroethyl ethyl sulphide (CEES) were characterized with respect to their toxicity in first passage cultures of proliferating human skin keratinocytes, the target cell of H-induced skin vesication. Agents H and T were equitoxic and half as toxic as agent Q. Hemi-sulphur mustard and CEES were approximately six times and seventeen times, respectively less cytotoxic than H. 2-Chloroethyl ethyl sulphide was only slightly less toxic in confluent cultures compared to actively proliferating cells. In contrast, the toxicity of H, Q, T and HSM significantly decreased as the cultures became confluent, paralleling the decreasing sensitivity of skin keratinocytes to H as they leave the basement membrane of the skin. The toxicity of CEES was maximal by 24h. In contrast, the maximal toxicity of the other four agents occurred at 48h, mirroring the latent period observed for these agents in vivo. The markedly different characteristics of toxicity between CEES and the other four test compounds indicate that it is likely that different mechanisms of action are operative between them. Caution should therefore be taken when interpreting the results of studies utilizing CEES as a simulant for the mechanistic study of H, or in the elucidation of medical countermeasures against this CW agent. It is also notable that the toxicity
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Toxicity of contaminated sediments in dilution series with control sediments
Nelson, M.K.; Landrum, P.F.; Burton, G.A.; Klaine, S.J.; Crecelius, E.A.; Byl, T.D.; Gossiaux, Duane C.; Tsymbal, V.N.; Cleveland, L.; Ingersoll, Christopher G.; Sasson-Brickson, G.
1993-01-01
The use of dilutions has been the foundation of our approach for assessing contaminated water, and accordingly, it may be important to establish similar or parallel approaches for sediment dilutions. Test organism responses to dilution gradients can identify the degree of necessary sediment alteration to reduce the toxicity. Using whole sediment dilutions to represent the complex interactions of in situ sediments can identify the toxicity, but the selection of the appropriate diluent for the contaminated sediment may affect the results and conclusions drawn. Contaminated whole sediments were examined to evaluate the toxicity of dilutions of sediments with a diversity of test organisms. Dilutions of the contaminated sediments were prepared with differing diluents that varied in organic carbon content, particle size distribution, and volatile solids. Studies were conducted using four macroinvertebrates and a vascular, rooted plant. Responses by some test organisms followed a sigmoidal dose-response curve, but others followed a U-shaped curve. Initial dilutions reduced toxicity as expected, but further dilution resulted in an increase in toxicity. The type of diluent used was an important factor in assessing the sediment toxicity, because the control soil reduced toxicity more effectively than sand as a diluent of the same sediment. Using sediment chemical and physical characteristics as an indicator of sediment dilution may not be as useful as chemical analysis of contaminants, but warrants further investigation.
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NASA Technical Reports Server (NTRS)
Kourtides, D. A.; Parker, J. A.; Hilado, C. J.
1977-01-01
The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use or being considered for use in aircraft interiors are described. The properties studied included thermomechanical properties such as glass-transition and melt temperature, changes in polymer enthalpy, thermogravimetric analysis in anerobic and oxidative environments, oxygen index, smoke evolution, relative toxicity of the volatile products of pyrolysis, and selected physical properties. The generic polymers evaluated included acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonate-poly (dimethylsiloxane) block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative rankings of some of the flammability, smoke, and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic than or equivalent to polymers in current use.
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NASA Astrophysics Data System (ADS)
Kang, Seunghyon; Kim, Ji-Eun; Kim, Daegyu; Woo, Chang Gyu; Pikhitsa, Peter V.; Cho, Myung-Haing; Choi, Mansoo
2015-09-01
The cellular toxicity of multi-walled carbon nanotubes (MWCNTs) and onion-like shell-shaped carbon nanoparticles (SCNPs) was investigated by analyzing the comparative cell viability. For the reasonable comparison, physicochemical characteristics were controlled thoroughly such as crystallinity, carbon bonding characteristic, hydrodynamic diameter, and metal contents of the particles. To understand relation between cellular toxicity of the particles and generation of reactive oxygen species (ROS), we measured unpaired singlet electrons of the particles and intracellular ROS, and analyzed cellular toxicity with/without the antioxidant N-acetylcysteine (NAC). Regardless of the presence of NAC, the cellular toxicity of SCNPs was found to be lower than that of MWCNTs. Since both particles show similar crystallinity, hydrodynamic size, and Raman signal with negligible contribution of remnant metal particles, the difference in cell viability would be ascribed to the difference in morphology, i.e., spherical shape (aspect ratio of one) for SCNP and elongated shape (high aspect ratio) for MWCNT.
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Zhang, Yingyi; Nakano, Jinichiro; Liu, Lili; Wang, Xidong; Zhang, Zuotai
2015-10-01
Energy recovery is a promising method for coal gangue utilization, during which the prevention of secondary pollution, especially toxic metal emission, is a significant issue in the development of coal gangue utilization. In the present study, investigation into trace element partitioning behavior from a coal gangue-fired power plant in Shanxi province, China, has been conducted. Besides the experimental analysis, thermodynamic equilibrium calculation was also conducted to help the further understanding on the effect of different parameters. Results showed that Hg, As, Be, and Cd were highly volatile elements in the combustion of coal gangue, which were notably enriched in fly ash and may be emitted into the environment via the gas phase. Cr and Mn were mostly non-volatile and were enriched in the bottom ash. Pb, Co, Zn, Cu, and Ni were semi-volatile elements and were enriched in the fly ash to varying degrees. Equilibrium calculations show that the air/fuel ratio and the presence of Cl highly affect the element volatility. The presence of mineral phases, such as aluminosilicates, depresses the volatility of elements by chemical immobilization and competition in Cl. The coal gangue, fly ash, and bottom ash all passed the toxicity characteristic leaching procedure (TCLP), and their alkalinity buffers the acidity of the solution and contributes to the low solubility of the trace elements.
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Liao, Wing-Ping; Yang, Renbo; Kuo, Wei-Ting; Huang, Jui-Yuan
2014-05-01
This research investigated the electrocoagulation of municipal solid waste incineration (MSWI) fly ash at a liquid-to-solid ratio (L/S) of 20:1. The leachate that was obtained from this treatment was recovered for reutilization. Two different anodic electrodes were investigated, and two unit runs were conducted. In Unit I, the optimum anode was chosen, and in Unit II, the optimum anode and the recovered leachate were used to replace deionized water for repeating the same electrocoagulation experiments. The results indicate that the aluminum (Al) anode performed better than the iridium oxide (IrO2) anode. The electrocoagulation technique includes washing with water, changing the composition of the fly ash, and stabilizing the heavy metals in the ash. Washing with water can remove the soluble salts from fly ash, and the fly ash can be converted into Friedel's salt (3CaO·Al2O3·CaCl2·10H2O) under an uniform electric field and the sacrificial release of Al(+3) ions, which stabilizes the toxic heavy metals and brings the composition of the fly ash to within the regulatory limits of the toxicity characteristic leaching procedure (TCLP). Use of the Al anode to manage the MSWI fly ash and the leachate obtained from the electrocoagulation treatment is therefore feasible. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Zhu, Hao; Wu, Chunfa; Wang, Jun; Zhang, Xumei
2018-04-16
Stabilization technology is one of widely used remediation technologies for cadmium (Cd)-contaminated agricultural soils, but stabilized Cd in soil may be activated again when external conditions such as acid rain occurred. Therefore, it is necessary to study the effect of acid rain on the performance of different stabilizing agents on Cd-polluted agriculture soils. In this study, Cd-contaminated soils were treated with mono-calcium phosphate (MCP), mono-ammonium phosphate (MAP), and artificial zeolite (AZ) respectively and incubated 3 months. These treatments were followed by two types of simulated acid rain (sulfuric acid rain and mixed acid rain) with three levels of acidity (pH = 3.0, 4.0, and 5.6). The chemical forms of Cd in the soils were determined by Tessier's sequential extraction procedure, and the leaching toxicities of Cd in the soils were assessed by toxicity characteristic leaching procedure (TCLP). The results show that the three stabilizing agents could decrease the mobility of Cd in soil to some degree with or without simulated acid rain (SAR) treatment. The stabilization performances followed the order of AZ < MAP < MCP. Acid rain soaking promoted the activation of Cd in stabilized soil, and both anion composition and pH of acid rain were two important factors that influenced the stabilization effect of Cd.
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[Adsorptive Stabilization of Soil Cr (VI) Using HDTMA Modified Montmorillonite].
2016-03-15
A series of organo-montomorillonites were prepared using Na-montomorillonite and hexadecyl trimethyl ammonium bromide (HDTMA). The organo-montomorillonites were then investigated for the remediation of Cr(VI) contaminated soils. FT-IR, XRD, SEM and N2 -BET, CEC, Zeta potential measurement were conducted to understand the structural changes of montmorillonites as different amounts of HDTMAs were added as modifier. The characterization results indicated that the clay interlayer spacing distance increased from 1. 25 nm to 2. 13 nm, the clay surface roughness decreased, the clay surface area reduced from 38.91 m² · g⁻¹ to 0.42 m² · g⁻¹, the clay exchangeable cation amount reduced from 62 cmol · kg⁻¹ to 9.9 cmol · kg⁻¹ and the clay surface charge changed from -29.1 mV to 5.59 mV as the dosage of HDTMA in montmorillonite was increased. The TCLP (toxicity characteristic leaching procedure) was used to evaluate the leachate toxicity of Cr(VI). The effects of the initial soil Cr(VI) concentration, montmorillonites dosage, reaction time and HDTMA modification amount were investigated, respectively. The results revealed that modification of montmorillonites would manifest an attenuated physical adsorptive effect and an enhanced electrostatic adsorptive effect on Cr(VI), suggesting electrostatic effect was the major force that resulted in improved Cr(VI) adsorption onto HDTMA modified montmorillonites.
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Effects of water quality parameters on boron toxicity to Ceriodaphnia dubia.
Dethloff, Gail M; Stubblefield, William A; Schlekat, Christian E
2009-07-01
The potential modifying effects of certain water quality parameters (e.g., hardness, alkalinity, pH) on the acute toxicity of boron were tested using a freshwater cladoceran, Ceriodaphnia dubia. By comparison, boron acute toxicity was less affected by water quality characteristics than some metals (e.g., copper and silver). Increases in alkalinity over the range tested did not alter toxicity. Increases in water hardness appeared to have an effect with very hard waters (>500 mg/L as CaCO(3)). Decreased pH had a limited influence on boron acute toxicity in laboratory waters. Increasing chloride concentration did not provide a protective effect. Boron acute toxicity was unaffected by sodium concentrations. Median acute lethal concentrations (LC(50)) in natural water samples collected from three field sites were all greater than in reconstituted laboratory waters that matched natural waters in all respects except for dissolved organic carbon. Water effect ratios in these waters ranged from 1.4 to 1.8. In subsequent studies using a commercially available source of natural organic matter, acute toxicity decreased with increased dissolved organic carbon, suggesting, along with the natural water studies, that dissolved organic carbon should be considered further as a modifier of boron toxicity in natural waters where it exceeds 2 mg/L.
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Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...
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The neglected nano-specific toxicity of ZnO nanoparticles in the yeast Saccharomyces cerevisiae
Zhang, Weicheng; Bao, Shaopan; Fang, Tao
2016-01-01
Nanoparticles (NPs) with unique physicochemical properties induce nano-specific (excess) toxicity in organisms compared with their bulk counterparts. Evaluation and consideration of nano-specific toxicity are meaningful for the safe design and environmental risk assessment of NPs. However, ZnO NPs have been reported to lack excess toxicity for diverse organisms. In the present study, the nano-specific toxicity of ZnO NPs was evaluated in the yeast Saccharomyces cerevisiae. Nano-specific toxicity of ZnO NPs was not observed in the wild type yeast. However, the ZnO NPs induced very similar nano-specific toxicities in the three mutants with comparable log Te (particle) values (0.64 vs 0.65 vs 0.62), suggesting that the mutants were more sensitive and specific for the NPs’ nano-specific toxicity. The toxic effects in the yeast were slightly attributable to dissolved zinc ions from the ZnO (nano or bulk) particles. Oxidative damage and mechanical damage contributed to the toxic effect of the ZnO particles. The mechanism of mechanical damage is proposed to be an inherent characteristic underlying the nano-specific toxicity in the mutants. The log Te (particle) was a useful parameter for evaluation of NPs nano-specific toxicity, whereas log Te (ion) efficiently determined the NPs toxicity associated with released ions. PMID:27094203
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The neglected nano-specific toxicity of ZnO nanoparticles in the yeast Saccharomyces cerevisiae
NASA Astrophysics Data System (ADS)
Zhang, Weicheng; Bao, Shaopan; Fang, Tao
2016-04-01
Nanoparticles (NPs) with unique physicochemical properties induce nano-specific (excess) toxicity in organisms compared with their bulk counterparts. Evaluation and consideration of nano-specific toxicity are meaningful for the safe design and environmental risk assessment of NPs. However, ZnO NPs have been reported to lack excess toxicity for diverse organisms. In the present study, the nano-specific toxicity of ZnO NPs was evaluated in the yeast Saccharomyces cerevisiae. Nano-specific toxicity of ZnO NPs was not observed in the wild type yeast. However, the ZnO NPs induced very similar nano-specific toxicities in the three mutants with comparable log Te (particle) values (0.64 vs 0.65 vs 0.62), suggesting that the mutants were more sensitive and specific for the NPs’ nano-specific toxicity. The toxic effects in the yeast were slightly attributable to dissolved zinc ions from the ZnO (nano or bulk) particles. Oxidative damage and mechanical damage contributed to the toxic effect of the ZnO particles. The mechanism of mechanical damage is proposed to be an inherent characteristic underlying the nano-specific toxicity in the mutants. The log Te (particle) was a useful parameter for evaluation of NPs nano-specific toxicity, whereas log Te (ion) efficiently determined the NPs toxicity associated with released ions.
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The neglected nano-specific toxicity of ZnO nanoparticles in the yeast Saccharomyces cerevisiae.
Zhang, Weicheng; Bao, Shaopan; Fang, Tao
2016-04-20
Nanoparticles (NPs) with unique physicochemical properties induce nano-specific (excess) toxicity in organisms compared with their bulk counterparts. Evaluation and consideration of nano-specific toxicity are meaningful for the safe design and environmental risk assessment of NPs. However, ZnO NPs have been reported to lack excess toxicity for diverse organisms. In the present study, the nano-specific toxicity of ZnO NPs was evaluated in the yeast Saccharomyces cerevisiae. Nano-specific toxicity of ZnO NPs was not observed in the wild type yeast. However, the ZnO NPs induced very similar nano-specific toxicities in the three mutants with comparable log Te ((particle)) values (0.64 vs 0.65 vs 0.62), suggesting that the mutants were more sensitive and specific for the NPs' nano-specific toxicity. The toxic effects in the yeast were slightly attributable to dissolved zinc ions from the ZnO (nano or bulk) particles. Oxidative damage and mechanical damage contributed to the toxic effect of the ZnO particles. The mechanism of mechanical damage is proposed to be an inherent characteristic underlying the nano-specific toxicity in the mutants. The log Te ((particle)) was a useful parameter for evaluation of NPs nano-specific toxicity, whereas log Te ((ion)) efficiently determined the NPs toxicity associated with released ions.
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LEACHING OF METALS FROM MINERAL PROCESSING WASTE
The purpose of this project is to test the leaching of Mineral processing Waste (MPW) contaminated with heavy metals using scientifically defendable leaching tests other than TCLP. Past experience and literature have shown that TCLP underestiates the levels of metals such as oxoa...
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LEACHING OF METALS FROM MINERAL PROCESSING WASTE
The purpose of this project is to test the leaching of Mineral Processing Waste (MPW) contaminated with heavy metals using scientifically defendable leaching tests other than TCLP. Past experience and literature have shown that TCLP underestimates the levels of metals such as oxo...
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Yin, Jian; Wang, Ai-Ping; Li, Wan-Fang; Shi, Rui; Jin, Hong-Tao; Wei, Jin-Feng
2018-01-01
The present work aims to explore the time-response (from 24 h to 96 h) characteristic and identify early potential sensitive biomarkers of copper (Cu) (as copper chloride dihydrate), cadmium (Cd) (as cadmium acetate), lead (Pb) (as lead nitrate) and chromium (Cr) (as potassium dichromate) exposure in adult zebrafish, focusing on reactive oxygen species (ROS), SOD activity, lipid peroxidation and gene expression related to oxidative stress and inflammatory response. Furthermore, the survival rate decreased apparently by a concentration-dependent manner after Cu, Cr, Cd and Pb exposure, and we selected non-lethal concentrations 0.05 mg/L for Cu, 15 mg/L for Cr, 3 mg/L for Cd and 93.75μg/L for Pb to test the effect on the following biological indicators. Under non-lethal concentration, the four heavy metals have no apparent histological change in adult zebrafish gills. Similar trends in ROS production, MDA level and SOD activity were up-regulated by the four heavy metals, while MDA level responded more sensitive to Pb by time-dependent manner than the other three heavy metals. In addition, mRNA levels related to antioxidant system (SOD1, SOD2 and Nrf2) were up-regulated by non-lethal concentration Cu, Cr, Cd and Pb exposure. MDA level and SOD1 gene have a more delayed response to heavy metals. Genes related to immunotoxicity were increased significantly after heavy metals exposure at non-lethal concentrations. TNF-α and IL-1β gene have similar sensibility to the four heavy metals, while IL-8 gene was more responsive to Cr, Cd and Pb exposure at 48 h groups and IFN-γ gene showed more sensitivity to Cu at 48 h groups than the other heavy metals. In conclusion, the present works have suggested that the IFN-γ gene may applied as early sensitive biomarker to identify Cu-induced toxicity, while MDA content and IL-8 gene may use as early sensitive biomarkers for evaluating the risk of Pb exposure. Moreover, IL-8 and IFN-γ gene were more responsive to heavy
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Sethurajan, Manivannan; Huguenot, David; Lens, Piet N L; Horn, Heinrich A; Figueiredo, Luiz H A; van Hullebusch, Eric D
2016-04-01
Various mineral processing operations to produce pure metals from mineral ores generate sludges, residues, and other unwanted by-products/wastes. As a general practice, these wastes are either stored in a reservoir or disposed in the surrounding of mining/smelting areas, which might cause adverse environmental impacts. Therefore, it is important to understand the various characteristics like heavy metal leaching features and potential toxicity of these metallurgical wastes. In this study, zinc plant leach residues (ZLRs) were collected from a currently operating Zn metallurgical industry located in Minas Gerais (Brazil) and investigated for their potential toxicity, fractionation, and leachability. Three different ZLR samples (ZLR1, ZLR2, and ZLR3) were collected, based on their age of production and deposition. They mainly consisted of Fe (6-11.5 %), Zn (2.5 to 5.0 %), and Pb (1.5 to 2.5 %) and minor concentrations of Al, Cd, Cu, and Mn, depending on the sample age. Toxicity Characteristic Leaching Procedure (TCLP) results revealed that these wastes are hazardous for the environment. Accelerated Community Bureau of Reference (BCR) sequential extraction clearly showed that potentially toxic heavy metals such as Cd, Cu, Pb, and Zn can be released into the environment in high quantities under mild acidic conditions. The results of the liquid-solid partitioning as a function of pH showed that pH plays an important role in the leachability of metals from these residues. At low pH (pH 2.5), high concentrations of metals can be leached: 67, 25, and 7 % of Zn can be leached from leach residues ZLR1, ZLR2, and ZLR3, respectively. The release of metals decreased with increasing pH. Geochemical modeling of the pH-dependent leaching was also performed to determine which geochemical process controls the leachability/solubility of the heavy metals. This study showed that the studied ZLRs contain significant concentrations of non-residual extractable fractions of Zn and can
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Suh, Mina; Troese, Matthew J; Hall, Debra A; Yasso, Blair; Yzenas, John J; Proctor, Debora M
2014-12-01
Electric arc furnace (EAF) steel slag is alkaline (pH of ~11-12) and contains metals, most notably chromium and nickel, and thus has potential to cause dermal irritation and sensitization at sufficient dose. Dermal contact with EAF slag occurs in many occupational and environmental settings because it is used widely in construction and other industrial sectors for various applications including asphaltic paving, road bases, construction fill, and as feed for cement kilns construction. However, no published study has characterized the potential for dermal effects associated with EAF slag. To assess dermal irritation, corrosion and sensitizing potential of EAF slag, in vitro and in vivo dermal toxicity assays were conducted based on the Organisation for Economic Co-operation and Development (OECD) guidelines. In vitro dermal corrosion and irritation testing (OECD 431 and 439) of EAF slag was conducted using the reconstructed human epidermal (RHE) tissue model. In vivo dermal toxicity and delayed contact sensitization testing (OECD 404 and 406) were conducted in rabbits and guinea pigs, respectively. EAF slag was not corrosive and not irritating in any tests. The results of the delayed contact dermal sensitization test indicate that EAF slag is not a dermal sensitizer. These findings are supported by the observation that metals in EAF slag occur as oxides of low solubility with leachates that are well below toxicity characteristic leaching procedure (TCLP) limits. Based on these results and in accordance to the OECD guidelines, EAF slag is not considered a dermal sensitizer, corrosive or irritant. Copyright © 2014 John Wiley & Sons, Ltd.
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Ecological impacts of lead mining on Ozark streams: toxicity of sediment and pore water.
Besser, John M; Brumbaugh, William G; Allert, Ann L; Poulton, Barry C; Schmitt, Christopher J; Ingersoll, Christopher G
2009-02-01
We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.
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Ecological impacts of lead mining on Ozark streams: Toxicity of sediment and pore water
Besser, J.M.; Brumbaugh, W.G.; Allert, A.L.; Poulton, B.C.; Schmitt, C.J.; Ingersoll, C.G.
2009-01-01
We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
NONE
1994-09-01
This final report from VFL Technologies for the pilot-scale thermal treatment of lower East Fork Poplar Creek floodplain soils dated September 1994 contains LEFPC Appendices, Volume 5, Appendix V - D. This appendix includes the final verification run data package (PAH, TCLP herbicides, TCLP pesticides).
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The risk of recrystallization: changes to the toxicity and morphology of pyrimethamine.
Perold, Zak; Caira, Mino R; Brits, Marius
2014-01-01
Pyrimethamine, an anti-malarial agent known to exhibit solid state polymorphism, may be purified by means of recrystallization. Recrystallization may alter the solid state chemistry of pharmaceuticals, which may impact the toxicity and/or manufacturability thereof. We evaluated the risks associated with the recrystallization of pyrimethamine. Pyrimethamine was recrystallized using several organic solvents. X-ray diffraction, thermal analysis, infra-red spectroscopy, microscopy, flowability -, solubility and dissolution testing as well as computational work were employed to evaluate the recrystallized products. A toxic solvatomorph of pyrimethamine (Pyr-MeOH) was found to be the product from methanol recrystallization. The elucidation of - and the elaboration on the unique characteristics of Pyr-MeOH provides the pharmaceutical industry with several means to identify Pyr-MeOH and to distinguish it from the pharmaceutically preferred anhydrous form (Pyr). Thermal methods of analysis found that the toxicity of Pyr-MeOH may be reversed by overcoming a desolvation activation energy of 148 kJ/mol. In addition it was found that recrystallization altered the morphology of Pyr. Angle of repose and tapped density determinations identified that the different morphologies of Pyr displayed differences in powder flow and compressibility behaviour and In Silico calculations were successful in rendering morphologies resembling that found experimentally. We present a solvatomorph of pyrimethamine and provide several characteristic means to identify this unwanted toxic form and quantified the energy required to overcome its toxicity. In addition we describe that Pyr may present in different morphologies and show how it may impact the manufacturability thereof.
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The Toxic Effects and Mechanisms of CuO and ZnO Nanoparticles
Chang, Ya-Nan; Zhang, Mingyi; Xia, Lin; Zhang, Jun; Xing, Gengmei
2012-01-01
Recent nanotechnological advances suggest that metal oxide nanoparticles (NPs) have been expected to be used in various fields, ranging from catalysis and opto-electronic materials to sensors, environmental remediation, and biomedicine. However, the growing use of NPs has led to their release into environment and the toxicity of metal oxide NPs on organisms has become a concern to both the public and scientists. Unfortunately, there are still widespread controversies and ambiguities with respect to the toxic effects and mechanisms of metal oxide NPs. Comprehensive understanding of their toxic effect is necessary to safely expand their use. In this review, we use CuO and ZnO NPs as examples to discuss how key factors such as size, surface characteristics, dissolution, and exposure routes mediate toxic effects, and we describe corresponding mechanisms, including oxidative stress, coordination effects and non-homeostasis effects.
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Treatment-Related Toxicities in Older Adults with Head and Neck Cancer: A Population-Based Analysis
O’Neill, Caitriona B.; Baxi, Shrujal S.; Atoria, Coral L.; O’Neill, James P.; Henman, Martin C.; Sherman, Eric J.; Lee, Nancy Y.; Pfister, David G.; Elkin, Elena B.
2016-01-01
Background Despite advantages in terms of cancer control and organ preservation, the benefits of chemoradiation (CTRT) may be offset by potentially severe, treatment-related toxicities particularly in older patients. Our objectives were to assess the type and frequency of toxicities in older adults with locally or regionally advanced, head and neck squamous cell carcinoma of the (HNSCC) receiving either primary CTRT or RT alone. Methods Using SEER cancer registry data linked with Medicare claims, we identified patients aged 66 years or older with locally advanced HNSCC, diagnosed 2001–2009, who received CTRT or RT alone. We examined differences in the frequency of toxicity-related hospital admissions and emergency room (ER) visits as well as feeding tube use and estimated the impact of chemotherapy on the likelihood of toxicity, controlling for demographic and disease characteristics. Results Of patients who received CTRT (N=1,502), 62% had a treatment-related toxicity, compared with 46% of patients who received RT alone (N=775). Controlling for demographic and disease characteristics, CTRT patients were twice as likely to experience an acute toxicity compared with their RT only peers. Fifty-five percent of CTRT patients had a feeding tube placed during or after treatment compared with 28% of the RT-only group. Conclusions In this population-based cohort of older adults with HNSCC, the rate of acute toxicities and feeding tube use in patients receiving CTRT was considerable. It is possible that for certain older patients, the potential benefit of adding CT to RT does not outweigh the harms of this combined modality therapy. PMID:25728057
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NASA Astrophysics Data System (ADS)
Chen, Jun; Li, Guoxiu; Zhang, Tao; Wang, Meng; Yu, Yusong
2016-12-01
Low toxicity ammonium dinitramide (ADN)-based aerospace propulsion systems currently show promise with regard to applications such as controlling satellite attitude. In the present work, the decomposition and combustion processes of an ADN-based monopropellant thruster were systematically studied, using a thermally stable catalyst to promote the decomposition reaction. The performance of the ADN propulsion system was investigated using a ground test system under vacuum, and the physical properties of the ADN-based propellant were also examined. Using this system, the effects of the preheating temperature and feed pressure on the combustion characteristics and thruster performance during steady state operation were observed. The results indicate that the propellant and catalyst employed during this work, as well as the design and manufacture of the thruster, met performance requirements. Moreover, the 1 N ADN thruster generated a specific impulse of 223 s, demonstrating the efficacy of the new catalyst. The thruster operational parameters (specifically, the preheating temperature and feed pressure) were found to have a significant effect on the decomposition and combustion processes within the thruster, and the performance of the thruster was demonstrated to improve at higher feed pressures and elevated preheating temperatures. A lower temperature of 140 °C was determined to activate the catalytic decomposition and combustion processes more effectively compared with the results obtained using other conditions. The data obtained in this study should be beneficial to future systematic and in-depth investigations of the combustion mechanism and characteristics within an ADN thruster.
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Toxicities of TNT and RDX to Terrestrial Plants in Five Soils with Contrasting Characteristics
2013-07-01
C.W.; Wentsel, R.S.; Nwanguma, R.O.; Sadusky, M. Toxicity Determination of Explosive Contaminated Soil Leachates to Daphnia magna Using an Adapted...UNCLASSIFIED Report (ADA270410). Hannink, N.K.; Rosser, S.J.; Bruce, N.C. Phytoremediation of Explosives. Crit. Rev. Plant Sci. 2002, 21, 511–538. Harvey
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Dose-finding designs using a novel quasi-continuous endpoint for multiple toxicities
Ezzalfani, Monia; Zohar, Sarah; Qin, Rui; Mandrekar, Sumithra J; Deley, Marie-Cécile Le
2013-01-01
The aim of a phase I oncology trial is to identify a dose with an acceptable safety profile. Most phase I designs use the dose-limiting toxicity, a binary endpoint, to assess the unacceptable level of toxicity. The dose-limiting toxicity might be incomplete for investigating molecularly targeted therapies as much useful toxicity information is discarded. In this work, we propose a quasi-continuous toxicity score, the total toxicity profile (TTP), to measure quantitatively and comprehensively the overall severity of multiple toxicities. We define the TTP as the Euclidean norm of the weights of toxicities experienced by a patient, where the weights reflect the relative clinical importance of each grade and toxicity type. We propose a dose-finding design, the quasi-likelihood continual reassessment method (CRM), incorporating the TTP score into the CRM, with a logistic model for the dose–toxicity relationship in a frequentist framework. Using simulations, we compared our design with three existing designs for quasi-continuous toxicity score (the Bayesian quasi-CRM with an empiric model and two nonparametric designs), all using the TTP score, under eight different scenarios. All designs using the TTP score to identify the recommended dose had good performance characteristics for most scenarios, with good overdosing control. For a sample size of 36, the percentage of correct selection for the quasi-likelihood CRM ranged from 80% to 90%, with similar results for the quasi-CRM design. These designs with TTP score present an appealing alternative to the conventional dose-finding designs, especially in the context of molecularly targeted agents. PMID:23335156
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The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States. - - - Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g. alkalinity ...
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Application of recombinant fluorescent mammalian cells as a toxicity biosensor.
Kim, E J; Lee, Y; Lee, J E; Gu, M B
2002-01-01
With respect to developing a more sensitive biosensor, a recombinant fluorescent Chinese Hamster Ovary cell line was used for the monitoring of various toxicants. Both cell lines, EFC-500 and KFC-A10, were able to detect toxicants sensitively. They were characterized with mitomycin C and gamma-ray as genotoxicants and bisphenol A, nonylphenol, ziram and methyl bromide as possible and known EDCs. When compared to each other, the response of KFC-A10 was generally more informative and sensitive. Compared to typical bacterial biosensor systems, these cell lines offered a sensitivity of 2- to 50-fold greater for the tested chemicals. Based on these results, the use of mammalian cells offers a sensitive biosensor system that is not only fast, cheap and reproducible but also capable of monitoring the endocrine-like characteristics of environmental toxicants.
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Toxicity of Carbon Nanotubes and its Implications for Occupational and Environmental Health
NASA Technical Reports Server (NTRS)
Lam, Chiu-wing; James, John T.
2007-01-01
This viewgraph document reviews the sources of Nano particles in the environment, the structure and properties of Carbon Nanotubes (CNTs), the physical characteristics of CNT materials, pulmonary and other health concerns of exposure to CNTs. The toxicity of CNT in rodents is summarized and some natural, and man-made sources of CNTs are shown. CNTs are electrically and thermally conductive, fibrous, biopersistent and very complicated in structures. The factors affecting toxicity of CNTs are more than size and surface area.
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Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Jin, Fei; Wu, Hao-Liang; Liu, Zhi-Bin
2014-12-15
Cement stabilization is used extensively to remediate soils contaminated with heavy metals. However, previous studies suggest that the elevated zinc (Zn) and lead (Pb) concentrations in the contaminated soils would substantially retard the cement hydration, leading to the deterioration of the performance of cement stabilized soils. This study presents a new binder, KMP, composed of oxalic acid-activated phosphate rock, monopotassium phosphate and reactive magnesia. The effectiveness of stabilization using this binder is investigated on soils spiked with Zn and Pb, individually and together. Several series of tests are conducted including toxicity characteristic leaching (TCLP), ecotoxicity in terms of luminescent bacteria test and unconfined compressive strength. The leachability of a field Zn- and Pb- contaminated soil stabilized with KMP is also evaluated by TCLP leaching test. The results show that the leached Zn concentrations are lower than the China MEP regulatory limit except when Zn and Pb coexist and for the curing time of 7 days. On the other hand, the leached Pb concentrations for stabilized soils with Pb alone or mixed Zn and Pb contamination are much lower than the China MEP or USEPA regulatory limit, irrespective of the curing time. The luminescent bacteria test results show that the toxicity of the stabilized soils has been reduced considerably and is classified as slightly toxic class. The unconfined compressive strength of the soils decrease with the increase in the Zn concentration. The stabilized soils with mixed Zn and Pb contaminants exhibit notably higher leached Zn concentration, while there is lower unconfined compressive strength relative to the soils when contaminated with Zn alone. The X-ray diffraction and scanning electron microscope analyses reveal the presence of bobierrite (Mg3(PO4)2·8H2O) and K-struvite (MgKPO4·6H2O) as the main products formed in the KMP stabilized uncontaminated soils; the formation of hopeite (Zn3(PO4)2·4H2O
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Park, Jinhee; Ra, Jin-Sung; Rho, Hojung; Cho, Jaeweon; Kim, Sang Don
2018-03-01
The objective of this study was to determine whether the water effect ratio (WER) or biotic ligand model (BLM) could be applied to efficiently develop water quality criteria (WQC) in Korea. Samples were collected from 12 specific sites along the Yeongsan River (YSR), Korea, including two sewage treatment plants and one estuary lake. A copper toxicity test using Daphnia magna was performed to determine the WER and to compare to the BLM prediction. The results of the WER from YSR samples also indicated significantly different copper toxicities in all sites. The model-based predictions showed that effluent and estuary waters had significantly different properties in regard to their ability to be used to investigate water characteristics and copper toxicity. It was supposed that the slight water characteristics changes, such as pH, DOC, hardness, conductivity, among others, influence copper toxicity, and these variable effects on copper toxicity interacted with the water composition. The 38% prediction was outside of the validation range by a factor of two in all sites, showing a poor predictive ability, especially in STPs and streams adjacent to the estuary, while the measured toxicity was more stable. The samples that ranged from pH 7.3-7.7 generated stable predictions, while other samples, including those with lower and the higher pH values, led to more unstable predictions. The results also showed that the toxicity of Cu in sample waters to D. magna was closely proportional to the amounts of acidity, including the carboxylic and phenolic groups, as well as the DOC concentrations. Consequently, the acceptable prediction of metal toxicity in various water samples needs the site-specific results considering the water characteristics such as pH and DOC properties particularly in STPs and estuary regions. Copyright © 2017 Elsevier Inc. All rights reserved.
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Autophagy as a Possible Underlying Mechanism of Nanomaterial Toxicity
Cohignac, Vanessa; Landry, Marion Julie; Boczkowski, Jorge; Lanone, Sophie
2014-01-01
The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s) still remain(s) unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity. PMID:28344236
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Industrial toxicants and Parkinson’s disease
Caudle, W. Michael; Guillot, Thomas S.; Lazo, Carlos R.; Miller, Gary W.
2012-01-01
The exposure of the human population to environmental contaminants is recognized as a significant contributing factor for the development of Parkinson’s disease (PD) and other forms of parkinsonism. While pesticides have repeatedly been identified as risk factors for PD, these compounds represent only a subset of environmental toxicants that we are exposed to on a regular basis. Thus, non-pesticide contaminants, such as metals, solvents, and other organohalogen compounds have also been implicated in the clinical and pathological manifestations of these movement disorders and it is these non-pesticide compounds that are the subject of this review. As toxic exposures to these classes of compounds can result in a spectrum of PD or PD-related disorders, it is imperative to appreciate shared clinico-pathological characteristics or mechanisms of action of these compounds in order to further delineate the resultant disorders as well as identify improved preventive strategies or therapeutic interventions. PMID:22309908
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Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.
Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene
2015-07-01
The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. © 2015 SETAC.
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Besser, John M.; Brumbaugh, William G.; Kemble, Nile E.; Ivey, Chris D.; Kunz, James L.; Ingersoll, Christopher G.; Rudel, David
2011-01-01
This report summarizes data from studies of the toxicity and bioavailability of nickel in nickel-spiked freshwater sediments. The goal of these studies was to generate toxicity and chemistry data to support development of broadly applicable sediment quality guidelines for nickel. The studies were conducted as three tasks, which are presented here as three chapters: Task 1, Development of methods for preparation and toxicity testing of nickel-spiked freshwater sediments; Task 2, Sensitivity of benthic invertebrates to toxicity of nickel-spiked freshwater sediments; and Task 3, Effect of sediment characteristics on nickel bioavailability. Appendices with additional methodological details and raw chemistry and toxicity data for the three tasks are available online at http://pubs.usgs.gov/sir/2011/5225/downloads/.
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Galleria mellonella larvae allow the discrimination of toxic and non-toxic chemicals.
Allegra, Enrico; Titball, Richard W; Carter, John; Champion, Olivia L
2018-05-01
The acute toxicities of 19 chemicals were assessed using G. mellonella larvae. The results obtained were compared against LD50 values derived from in vitro cytotoxicity tests and against in vivo acute oral LD50 values. In general, cell culture systems overestimated the toxicity of chemicals, especially low toxicity chemicals. In contrast, toxicity testing in G. mellonella larvae was found to be a reliable predictor for low toxicity chemicals. For the 9 chemicals tested which were assigned to Globally Harmonised System (GHS) category 5, the toxicity measured in G. mellonella larvae was consistent with their GHS categorisation but cytotoxicity measured in 3T3 or NHK cells predicted 4 out of 9 chemicals as having low toxicity. A more robust assessment of the likely toxicity of chemicals in mammals could be made by taking into account their toxicities in both cell cultures and in G. mellonella larvae. Copyright © 2018 Elsevier Ltd. All rights reserved.
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2002-02-01
Prepared for the United States Air Force Approved for public release; distribution unlimited Theodore Karasik Project AIR FORCE R TOXIC WARFARE...Report Documentation Page Report Date 000002002 Report Type N/A Dates Covered (from... to) - Title and Subtitle Toxic Warfare Contract Number Grant...310) 451-6915; Email: order@rand.org Library of Congress Cataloging-in-Publication Data Karasik, Theodore William. Toxic warfare / Theodore Karasik
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DETECTION OF TOXICANT(S) ON BUILDING SURFACES FOLLOWING CHEMICAL ATTACK
A critical step prior to reoccupation of any facility following a chemical attack is monitoring for toxic compounds on surfaces within that facility. Low level detection of toxicant(s) is necessary to ensure that these compounds have been eliminated after building decontaminatio...
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Nanomaterials and nanoparticles: sources and toxicity.
Buzea, Cristina; Pacheco, Ivan I; Robbie, Kevin
2007-12-01
understanding the toxicity of nanoparticles is that their minute size, smaller than cells and cellular organelles, allows them to penetrate these basic biological structures, disrupting their normal function.Examples of toxic effects include tissue inflammation, and altered cellular redox balance toward oxidation, causing abnormal function or cell death. The manipulation of matter at the scale of atoms,"nanotechnology," is creating many new materials with characteristics not always easily predicted from current knowledge. Within the nearly limitless diversity of these materials, some happen to be toxic to biological systems, others are relatively benign, while others confer health benefits. Some of these materials have desirable characteristics for industrial applications, as nanostructured materials often exhibit beneficial properties, from UV absorbance in sunscreen to oil-less lubrication of motors.A rational science-based approach is needed to minimize harm caused by these materials, while supporting continued study and appropriate industrial development. As current knowledge of the toxicology of "bulk" materials may not suffice in reliably predicting toxic forms of nanoparticles,ongoing and expanded study of "nanotoxicity" will be necessary. For nanotechnologies with clearly associated health risks, intelligent design of materials and devices is needed to derive the benefits of these new technologies while limiting adverse health impacts. Human exposure to toxic nanoparticles can be reduced through identifying creation-exposure pathways of toxins, a study that may someday soon unravel the mysteries of diseases such as Parkinson's and Alzheimer's. Reduction in fossil fuel combustion would have a large impact on global human exposure to nanoparticles, as would limiting deforestation and desertification.While nanotoxicity is a relatively new concept to science, this review reveals the result of life's long history of evolution in the presence of nanoparticles, and how the
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Section 10: Ground Water - Waste Characteristics & Targets
HRS Training. The waste characteristics factor category in the ground water pathway is made up of two components: the toxicity/mobility of the most hazardous substance associated with the site and the hazardous waste quantity at the site.
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Yahara, I; Furukawa, H; Sato, K; Nishimura, K; Harihara, A; Yabuuchi, K; Miyauchi, H; Kii, Y; Muraoka, Y; Kitamura, T; Kato, I
2001-05-01
A single oral dose toxicity study of Cefmatilen hydrochloride hydrate (S-1090) and a single intravenous dose toxicity study of its sodium salt (S-1090-Na) were conducted in rats. One dose level of 2000 mg potency/kg was set in both studies. Single oral dose toxicity study of S-1090 No deaths occurred. Diarrhea occurred on the dosing day and slightly soft feces lasted until 6 days after administration. These changes were considered to result from changes of intestinal flora induced by the antibiotic activity of S-1090. Reddish-brown feces (due to chelated products of S-1090 or its decomposition products with Fe3+ in the diet) were also observed until the next day after administration. Body weights increased favorably, and no S-1090-related pathological changes were observed. The oral lethal dose of S-1090 was estimated to be more than 2000 mg potency/kg. Single intravenous dose toxicity study of S-1090-Na No deaths occurred. The rats showed characteristic clinical signs such as hypoactivity, abnormal gait and hypopnea immediately after dosing, and some rats showed prone position or paleness of eyeballs and ear auricles in due course. These signs disappeared by 4 hr after administration. Slightly soft feces and reddish-brown feces were observed much the same as in the orally-treated rats. Body weights increased favorably. In the pathological examinations, slight cecal enlargement and increased basophilia, dilatation and calcification of the renal tubules in the kidney were observed. The intravenous lethal dose of S-1090-Na was estimated to be more than 2000 mg potency/kg.
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How toxic is coal ash? A laboratory toxicity case study
Sherrard, Rick M.; Carriker, Neil; Greeley, Jr., Mark Stephen
2014-12-08
Under a consent agreement among the Environmental Protection Agency (EPA) and proponents both for and against stricter regulation, EPA is to issue a new coal ash disposal rule by the end of 2014. Laboratory toxicity investigations often yield conservative estimates of toxicity because many standard test species are more sensitive than resident species, thus could provide information useful to the rule-making. However, few laboratory studies of coal ash toxicity are available; most studies reported in the literature are based solely on field investigations. In this paper, we describe a broad range of toxicity studies conducted for the Tennessee Valley Authoritymore » (TVA) Kingston ash spill, results of which help provide additional perspective on the toxicity of coal ash.« less
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Molecular Mechanisms of Aldehyde Toxicity: A Chemical Perspective
2015-01-01
Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause “type-2 alkene toxicity” through additive interactions
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Classification of baseline toxicants for QSAR predictions to replace fish acute toxicity studies.
Nendza, Monika; Müller, Martin; Wenzel, Andrea
2017-03-22
Fish acute toxicity studies are required for environmental hazard and risk assessment of chemicals by national and international legislations such as REACH, the regulations of plant protection products and biocidal products, or the GHS (globally harmonised system) for classification and labelling of chemicals. Alternative methods like QSARs (quantitative structure-activity relationships) can replace many ecotoxicity tests. However, complete substitution of in vivo animal tests by in silico methods may not be realistic. For the so-called baseline toxicants, it is possible to predict the fish acute toxicity with sufficient accuracy from log K ow and, hence, valid QSARs can replace in vivo testing. In contrast, excess toxicants and chemicals not reliably classified as baseline toxicants require further in silico, in vitro or in vivo assessments. Thus, the critical task is to discriminate between baseline and excess toxicants. For fish acute toxicity, we derived a scheme based on structural alerts and physicochemical property thresholds to classify chemicals as either baseline toxicants (=predictable by QSARs) or as potential excess toxicants (=not predictable by baseline QSARs). The step-wise approach identifies baseline toxicants (true negatives) in a precautionary way to avoid false negative predictions. Therefore, a certain fraction of false positives can be tolerated, i.e. baseline toxicants without specific effects that may be tested instead of predicted. Application of the classification scheme to a new heterogeneous dataset for diverse fish species results in 40% baseline toxicants, 24% excess toxicants and 36% compounds not classified. Thus, we can conclude that replacing about half of the fish acute toxicity tests by QSAR predictions is realistic to be achieved in the short-term. The long-term goals are classification criteria also for further groups of toxicants and to replace as many in vivo fish acute toxicity tests as possible with valid QSAR
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The first fatal case of yam bean and rotenone toxicity in Thailand.
Narongchai, Paitoon; Narongchai, Siripun; Thampituk, Suparat
2005-07-01
The first fatal case of Yam bean and Rotenone toxicity in Thailand was studied at Forensic Medicine, Chiang Mai, Thailand. A Chinese Taiwan man, 59 years old, was found dead after Yam bean ingestion. Yam bean toxicity and death have been found very rarely in the world and has not been reported in Thailand The Yam bean plant is grown widely in Northern Thailand. But many people know that mature pods, seeds and filage of the Yam bean, except the tuberous root, are very toxic. The victim ate a lot of Yam bean seeds and died within 2 hours with respiratory failure. The authors detected Rotenone substance in Yam bean seeds, gastric content and 72 ng/ml blood by HPLC. Also generalized microscopic hemorrhage in the brain, lungs, liver and adrenal glands which were of characteristic pathology were detected. The authors concluded that the cause of death was asphyxia from Yam bean or Rotenone toxicity.
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Translation of Toxicity Data into CW Agent Toxicity Estimates
2003-07-01
UNLIMITED UNCLASSIFIED/UNLIMITEDPrepared by Douglas R. Sommerville, PE US Army ECBC, APG, MD Dependence of Toxic Effect on Exposure Time Inhalation (IH...to longer exposure durations. Toxicity estimates for exposure durations ranging from 2 to 360 minutes have been derived for six agents (GA, GB, GD...individuals having effects greater in severity than the defining effect of the ECTYY Cn T = k Toxic load equation 5 6 Edgewood Chemical Biological Center
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Mutation assays involving blood cells that metabolize toxic substances
Crespi, Charles L.; Thilly, William G.
1985-01-01
A line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity) is disclosed. Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. Mutation assays using these cells, and other cells with similar characteristics, are also disclosed.
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The taste of toxicity: A quantitative analysis of bitter and toxic molecules.
Nissim, Ido; Dagan-Wiener, Ayana; Niv, Masha Y
2017-12-01
The role of bitter taste-one of the few basic taste modalities-is commonly assumed to signal toxicity and alert animals against consuming harmful compounds. However, it is known that some toxic compounds are not bitter and that many bitter compounds have negligible toxicity while having important health benefits. Here we apply a quantitative analysis of the chemical space to shed light on the bitterness-toxicity relationship. Using the BitterDB dataset of bitter molecules, The BitterPredict prediction tool, and datasets of toxic compounds, we quantify the identity and similarity between bitter and toxic compounds. About 60% of the bitter compounds have documented toxicity and only 56% of the toxic compounds are known or predicted to be bitter. The LD 50 value distributions suggest that most of the bitter compounds are not very toxic, but there is a somewhat higher chance of toxicity for known bitter compounds compared to known nonbitter ones. Flavonoids and alpha acids are more common in the bitter dataset compared with the toxic dataset. In contrast, alkaloids are more common in the toxic datasets compared to the bitter dataset. Interestingly, no trend linking LD 50 values with the number of activated bitter taste receptors (TAS2Rs) subtypes is apparent in the currently available data. This is in accord with the newly discovered expression of TAS2Rs in several extra-oral tissues, in which they might be activated by yet unknown endogenous ligands and play non-gustatory physiological roles. These results suggest that bitter taste is not a very reliable marker for toxicity, and is likely to have other physiological roles. © 2017 IUBMB Life, 69(12):938-946, 2017. © 2017 International Union of Biochemistry and Molecular Biology.
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Suga, Hirotaka; Shiraishi, Tomohiro; Takushima, Akihiko; Harii, Kiyonori
2016-01-01
Toxic shock syndrome is a rare but life-threatening complication after plastic surgery procedures. We experienced 2 cases of toxic shock syndrome after expander-based breast reconstruction caused by methicillin-resistant Staphylococcus aureus. The first patient took a severe clinical course due to the delayed diagnosis and treatment, and the second patient recovered rapidly after the early diagnosis and treatment based on our experience of the first case. Fever, rash, and gastrointestinal symptoms (diarrhea and/or vomiting) were characteristic and important for the early diagnosis of toxic shock syndrome. Considering the increased prevalence of methicillin-resistant Staphylococcus aureus, we should suspect methicillin-resistant Staphylococcus aureus in cases of toxic shock syndrome that occur postoperatively, and the empiric administration of vancomycin should be initiated in such cases.
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A major uncertainty in many aquatic risk assessments for toxic chemicals is the aggregate effect of the physicochemical characteristics of exposure media on toxicity, and how this affects extrapolation of laboratory test results to natural systems. A notable example of this is h...
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Gaseous emissions and toxic hazards associated with plastics in fire situations: A literature review
NASA Technical Reports Server (NTRS)
Junod, T. L.
1976-01-01
The hazards of plastics in fire situations, the gases emitted, the factors influencing the nature of these emissions, the characteristics of toxic gases, and the results of laboratory studies, are discussed. The literature pertaining to the pyrolysis and oxidation of plastics was reviewed. An effort was made to define the state of the art for determining the toxic gases emitted by plastics under fire conditions. Recommendations are made and research needs defined as a result of this review.
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Elevating ambient temperature above thermoneutrality exacerbates toxicity of most air pollutants, insecticides, and other toxic chemicals. On the other hand, safety and toxicity testing of toxicants and drugs is usually performed in mice and rats maintained at subthermoneutral te...
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Huang, Su-Chen; Chang, Fang-Chih; Lo, Shang-Lien; Lee, Ming-Yu; Wang, Chu-Fang; Lin, Jyh-Dong
2007-06-01
In this study, artificial lightweight aggregate (LWA) manufactured from recycled resources was investigated. Residues from mining, fly ash from an incinerator and heavy metal sludge from an electronic waste water plant were mixed into raw aggregate pellets and fed into a tunnel kiln to be sintered and finally cooled rapidly. Various feeding and sintering temperatures were employed to examine their impact on the extent of vitrification on the aggregate surface. Microstructural analysis and toxicity characteristic leaching procedure (TCLP) were also performed. The results show that the optimum condition of LWA fabrication is sintering at 1150 degrees C for 15 min with raw aggregate pellets fed at 750 degrees C. The rapidly vitrified surface envelops the gas produced with the increase in internal temperature and cooling by spraying water prevents the aggregates from binding together, thus forming LWA with specific gravity of 0.6. LWA produced by sintering in tunnel kiln shows good vitrified surface, low water absorption rate below 5%, and low cylindrical compressive strength of 4.3 MPa. In addition, only trace amounts of heavy metals were detected, making the LWA non-hazardous for construction use.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
None, None
1999-09-01
Through efforts led by the Mixed Waste Focus Area (MWFA) and its Mercury Working Group (HgWG), the inventory of bulk elemental mercury contaminated with radionuclides stored at various U.S. Department of Energy (DOE) sites is thought to be approximately 16 m3 (Conley et al. 1998). At least 19 different DOE sites have this type of mixed low-level waste in their storage facilities. The U.S. Environmental Protection Agency (EPA) specifies amalgamation as the treatment method for radioactively contaminated elemental mercury. Although the chemistry of amalgamation is well known, the practical engineering of a sizable amalgamation process has not been tested (Tysonmore » 1993). To eliminate the existing DOE inventory in a reasonable timeframe, scalable equipment is needed that can produce waste forms that meet the EPA definition of amalgamation, produce waste forms that pass the EPA Toxicity Characteristic Leaching Procedure (TCLP) limit of 0.20 mg/L, limit mercury vapor concentrations during processing to below the Occupational Safety and Health Administration’s (OSHA) 8-h worker exposure limit (50 mg/m3) for mercury, and perform the above economically.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
None, None
1999-09-01
Through efforts led by the Mixed Waste Focus Area (MWFA) and its Mercury Working Group (HgWG), the inventory of bulk elemental mercury contaminated with radionuclides stored at various U. S. Department of Energy (DOE) sites is thought to be approximately 16 m3 (Conley et al. 1998). At least 19 different DOE sites have this type of mixed low-level waste in their storage facilities. The U. S. Environmental Protection Agency (EPA) specifies amalgamation as the treatment method for radioactively contaminated elemental mercury. Although the chemistry of amalgamation is well known, the practical engineering of a sizable amalgamation process has not beenmore » tested (Tyson 1993). To eliminate the existing DOE inventory in a reasonable timeframe, scaleable equipment is needed that can: produce waste forms that meet the EPA definition of amalgamation, produce waste forms that pass the EPA Toxicity Characteristic Leaching Procedure (TCLP) limit of 0.20 mg/L, limit mercury vapor concentrations during processing to below the Occupational Safety and Health Administration’s (OSHA) 8-hour worker exposure limit (50 mg/m3) for mercury, and perform the above economically.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Veazey, G.W.; Schake, A.R.; Shalek, P.D.
1996-10-01
The process used at TA-55 to cement transuranic (TRU) waste has experienced several problems with the gypsum-based cement currently being used. Specifically, the waste form could not reliably pass the Waste Isolation Pilot Plant (WIPP) prohibition for free liquid and the Environmental Protection Agency (EPA)-Toxicity Characteristic Leaching Procedure (TCLP) standard for chromium. This report describes the project to develop a portland cement-based waste form that ensures compliance to these standards, as well as other performance standards consisting of homogeneous mixing, moderate hydration temperature, timely initial set, and structural durability. Testing was conducted using the two most common waste streams requiringmore » cementation as of February 1994, lean residue (LR)- and oxalate filtrate (OX)-based evaporator bottoms (EV). A formulation with a pH of 10.3 to 12.1 and a minimum cement-to-liquid (C/L) ratio of 0.80 kg/l for OX-based EV and 0.94 kg/L for LR-based EV was found to pass the performance standards chosen for this project. The implementation of the portland process should result in a yearly cost savings for raw materials of approximately $27,000 over the gypsum process.« less
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Emission factors of air toxics from semiconductor manufacturing in Korea.
Eom, Yun-Sung; Hong, Ji-Hyung; Lee, Suk-Jo; Lee, Eun-Jung; Cha, Jun-Seok; Lee, Dae-Gyun; Bang, Sun-Ae
2006-11-01
The development of local, accurate emission factors is very important for the estimation of reliable national emissions and air quality management. For that, this study is performed for pollutants released to the atmosphere with source-specific emission tests from the semiconductor manufacturing industry. The semiconductor manufacturing industry is one of the major sources of air toxics or hazardous air pollutants (HAPs); thus, understanding the emission characteristics of the emission source is a very important factor in the development of a control strategy. However, in Korea, there is a general lack of information available on air emissions from the semiconductor industry. The major emission sources of air toxics examined from the semiconductor manufacturing industry were wet chemical stations, coating applications, gaseous operations, photolithography, and miscellaneous devices in the wafer fabrication and semiconductor packaging processes. In this study, analyses of emission characteristics, and the estimations of emission data and factors for air toxics, such as acids, bases, heavy metals, and volatile organic compounds from the semiconductor manufacturing process have been performed. The concentration of hydrogen chloride from the packaging process was the highest among all of the processes. In addition, the emission factor of total volatile organic compounds (TVOCs) for the packaging process was higher than that of the wafer fabrication process. Emission factors estimated in this study were compared with those of Taiwan for evaluation, and they were found to be of similar level in the case of TVOCs and fluorine compounds.
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Radio-toxicity of spent fuel of the advanced heavy water reactor.
Anand, S; Singh, K D S; Sharma, V K
2010-01-01
The Advanced Heavy Water Reactor (AHWR) is a new power reactor concept being developed at Bhabha Atomic Research Centre, Mumbai. The reactor retains many desirable features of the existing Pressurised Heavy Water Reactor (PHWR), while incorporating new, advanced safety features. The reactor aims to utilise the vast thorium resources available in India. The reactor core will use plutonium as the make-up fuel, while breeding (233)U in situ. On account of this unique combination of fuel materials, the operational characteristics of the fuel as determined by its radioactivity, decay heat and radio-toxicity are being viewed with great interest. Radio-toxicity of the spent fuel is a measure of potential radiological hazard to the members of the public and also important from the ecological point of view. The radio-toxicity of the AHWR fuel is extremely high to start with, being approximately 10(4) times that of the fresh natural U fuel used in a PHWR, and continues to remain relatively high during operation and subsequent cooling. A unique feature of this fuel is the peak observed in its radio-toxicity at approximately 10(5) y of decay cooling. The delayed increase in fuel toxicity has been traced primarily to a build-up of (229)Th, (230)Th and (226)Ra. This phenomenon has been observed earlier for thorium-based fuels and is confirmed for the AHWR fuel. This paper presents radio-toxicity data for AHWR spent fuel up to a period of 10(6) y and the results are compared with the radio-toxicity of PHWR.
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Toxicity Studies on Antiradiation Agents.
1979-03-01
Mice 193-403 WI 2823 Acute Oral and IP Toxicity in Guinea Pigs 193-404 WR 2823 14-Day IV Toxicity in Rats 193-405 WI 2823 Acute IV Toxicity in Dogs ...193-406 W 2823 14-Day Subacute IV Toxicity in Dogs 193-407 WI 2721 28-Day Oral Toxicity in Monkeys 193-408 WI 2529 Acute Oral Toxicity in Mice 193-409... Dogs 193-415 WI 149, 024 Acute IV Toxicity in Monkeys 193-416 WI 149, 024 2-Week IV Toxicity in Dogs 193-417 WI 149, 024 2-Week Toxicity in Monkeys 193
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Mutation assays involving blood cells that metabolize toxic substances
Crespi, C.L.; Thilly, W.G.
1999-08-10
The present invention pertains to a line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity). Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. The invention also includes mutation assays using these cells, and other cells with similar characteristics. 3 figs.
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Mutation assays involving blood cells that metabolize toxic substances
Crespi, Charles L.; Thilly, William G.
1999-01-01
The present invention pertains to a line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity). Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. The invention also includes mutation assays using these cells, and other cells with similar characteristics.
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Bordoloi, Shreemoyee; Nath, Suresh K; Gogoi, Sweety; Dutta, Robin K
2013-09-15
A three-step treatment process involving (i) mild alkaline pH-conditioning by NaHCO₃; (ii) oxidation of arsenite and ferrous ions by KMnO₄, itself precipitating as insoluble MnO₂ under the pH condition; and (iii) coagulation by FeCl₃ has been used for simultaneous removal of arsenic and iron ions from water. The treated water is filtered after a residence time of 1-2 h. Laboratory batch experiments were performed to optimize the doses. A field trial was performed with an optimized recipe at 30 households and 5 schools at some highly arsenic affected villages in Assam, India. Simultaneous removals of arsenic from initial 0.1-0.5 mg/L to about 5 μg/L and iron from initial 0.3-5.0 mg/L to less than 0.1 mg/L have been achieved along with final pH between 7.0 and 7.5 after residence time of 1h. The process also removes other heavy elements, if present, without leaving any additional toxic residue. The small quantity of solid sludge containing mainly ferrihydrite with adsorbed arsenate passes the toxicity characteristic leaching procedure (TCLP) test. The estimated recurring cost is approximately USD 0.16 per/m(3) of purified water. A high efficiency, an extremely low cost, safety, non-requirement of power and simplicity of operation make the technique potential for rural application. Copyright © 2013 Elsevier B.V. All rights reserved.
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[Study on composite stabilization of arsenic (As) contaminated soil].
Wang, Hao; Pan, Li-xiang; Zhang, Xiang-yu; Li, Meng; Song, Bao-hua
2013-09-01
Since the contaminated soil may contain various kinds of heavy metals, use of single chemical reagent leads to poor remediation and high cost. In this study, soil containing As, Zn, Cd was sampled, and different reagents were selected to carry out the rapid stabilization of contaminated soil. The TCLP (toxicity characteristic leaching procedure) was used to evaluate the leachate toxicity of heavy metals and the results indicated that calcium-containing, sulphur-containing and iron-containing reagents had good performance in reducing the metal mobility. The stabilization efficiency of the six reagents tested ranked in the order of CaO > Na2S > organic sulfur > Chitosan > FeSO4 > (C2H5)2NCS2Na. Two types of reagents (six reagents) were combined based on the target properties of different reagents and the stabilization efficiency was evaluated and analyzed. The results indicated that the composite reagents had higher stabilization efficiency: the efficiency of 3% FeSO4 + 5% CaO was 81.7%, 97.2% and 68.2% for As, Cd and Zn, respectively, and the efficiency of 3% CaO + 5% organic sulfur was 76.6%, 95.7% and 93.8% for these three metals, respectively. Speciation analysis was carried out in this study and the results suggested that it was the change of metals from the exchangeable state to the reduction (for inorganic reagent) or oxidation state (for organic reagent) that caused the soil stabilization and the degree of change determined the stabilization efficiency.
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Yao, Jun; Li, Wenbing; Xia, Fangfang; Zheng, Yuange; Fang, Chengran; Shen, Dongsheng
2012-06-01
Fly ash samples were taken from solid waste incinerators with different feeding waste, furnace type, and air pollution control device in six cities of Zhejiang province. The solid waste incinerators there constitute one fifth of incinerators in China. Heavy metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in the fly ash. Moreover, the fly ash samples were extracted by toxicity characteristic leaching procedure (TCLP). The biotoxicity of the leachate was evaluated by Chlorella pyrenoidosa. High variation and contents were found for both the heavy metals and PCDD/Fs. The contents of Zn, Cu, As, Pb, Cd, Cr, Ni, and Hg in the fly ash samples varied from 300 to 32,100, 62.1-1175, 1.1-57, 61.6-620, 0.4-223, 16.6-4380, 1.2-94.7, and 0.03-1.4 μg g(-1) dw, respectively. The total contents of 17 PCDD/Fs varied from 0.1128 to 127.7939 μg g(-1) dw, and the 2,3,7,8-TeCDD toxic equivalents (TEQ) of PCDD/Fs ranged from 0.009 to 6.177 μg g(-1) dw. PCDF congeners were the main contributor to the TEQ. The leachate of the fly ash showed biotoxicity to C. pyrenoidosa. A significant correlation was found between the Cd and EC(50) values. Further research is required to investigate the environmental impact of the various pollutants in the fly ash.
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This chapter provides an overview the developmental toxicity resulting from exposure to perfluorinated alkyl acids (PFAAs). The majority of studies of PFAA-induced developmental toxicity have examined effects of perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA) a...
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Persistent toxic substances: sources, fates and effects.
Wong, Ming H; Armour, Margaret-Ann; Naidu, Ravi; Man, Ming
2012-01-01
Persistent toxic substances (PTS) include the Stockholm persistent organic pollutants, like dichlorodiphenyltrichloroethane, polychlorinated biphenyls, dioxin/furan, etc., and organometallic compounds, like organomercury, organotin, and organolead, which all share the same characteristics of being persistent, toxic, bioaccumulative, and able to travel long distances through different media. The adverse health effects of some of the emerging chemicals like pentabromodiphenyl ether, bisphenol A, and di(2-ethylhexyl)phthalate, which are widely used in daily appliances (e.g., TVs, computers, mobile phones, plastic baby bottles), have become a public health concern due to more evidence now available showing their adverse effects like disturbance of the endocrine system and cancer. This article is an attempt to review the current status of PTS in our environment, citing case studies in China and North America, and whether our existing drinking water treatment and wastewater treatment processes are adequate in removing them from water. Some management issues of these emerging chemicals of concern are also discussed.
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Chelant extraction of heavy metals from contaminated soils.
Peters, R W
1999-04-23
, the soil was successfully treated passing both the Toxicity Characteristics Leaching Procedure (TCLP) and EPA Total Extractable Metal Limit. The final residual Pb concentration was about 300 mg/kg, with a corresponding TCLP of 1.5 mg/l. Removal of the exchangeable and carbonate fractions for Cu and Zn was achieved during the first extraction stage, whereas it required two extraction stages for the same fractions for Pb. Removal of Pb, Cu, and Zn present as exchangeable, carbonates, and reducible oxides occurred between the fourth- and fifth-stage extractions. The overall removal of copper, lead, and zinc from the multiple-stage washing were 98.9%, 98.9%, and 97.2%, respectively. The concentration and operating conditions for the soil washing extractions were not necessarily optimized. If the conditions had been optimized and using a more representative Pb concentration (approximately 12000 mg/kg), it is likely that the TCLP and residual heavy metal soil concentrations could be achieved within two to three extractions. The results indicate that the J-Field contaminated soils can be successfully treated using a soil washing technique. Copyright 1999 Published by Elsevier Science B.V.
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Clinical and microscopic characteristics of canine toxic epidermal necrolysis.
Banovic, F; Olivry, T; Bazzle, L; Tobias, J R; Atlee, B; Zabel, S; Hensel, N; Linder, K E
2015-03-01
Canine toxic epidermal necrosis (TEN), a rare and life-threatening cutaneous drug reaction, traditionally has been described as full-thickness devitalization of the epidermis with minimal dermal inflammation; however, few reports detail the histologic findings. We characterize the clinical features and histologic variations of 3 canine TEN patients. Clinically, irregular erythematous and purpuric macules evolved into widespread and severely painful erosions. The number of eroded mucosae varied; however, periocular and perilabial mucocutaneous junctions frequently were affected. Thirteen of 17 biopsies were evaluated. Apoptosis at multiple epidermal levels was the most common pattern of epidermal necrosis (12/13 biopsies, 92%). In contrast, full-thickness coagulation necrosis was present less often (7/13 biopsies, 52%). Lymphocytic interface dermatitis was the predominant inflammatory pattern, and intraepidermal lymphocytes, along with fewer histiocytes, were present to some degree in all samples along with lymphocytic satellitosis of apoptotic keratinocytes. The sequence of changes points to lymphocyte-mediated keratinocyte apoptosis as an early step in lesion development with subsequent variation in progression to coagulation necrosis among patients. Histopathologic changes overlapped with those reported for erythema multiforme, in contrast to traditional histologic descriptions of canine TEN. A specific algorithm for assessment of drug causality in epidermal necrolysis (ALDEN) was applied for each patient; carprofen was associated with a probable score for causality in 1 dog. Clinicians should be encouraged to take multiple biopsies in TEN suspect cases as nearly 25% of all biopsies lacked epithelium and were not diagnostic. © The Author(s) 2014.
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Immobilization of radioactive and hazardous wastes in a developed sulfur polymer cement (SPC) matrix
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wagdy, M.; Azim, Abdel; El-Gammal, Belal
Available in abstract form only. Full text of publication follows: A process has been developed for the immobilization Cs, Sr, Ce, Pb, and Cr in forms that is non-dispersible and could be safely immobilized. The simulated radioactive wastes of Cs, Sr, and Ce, and the hazardous wastes of Cr, and Pb were immobilized in the stable form of sulfur polymer cement (SPC). In this process, the contaminants (in a single form) were added to the sulfur mixture of sulfur and aromatic /or aliphatic hydrocarbons that used as polymerizing agents for sulfur (95% S, and 5% organic polymer by weight). Durabilitymore » of the fabricated SPC matrices was assessed in terms of their water of immersion, porosity, and compressive strength. The water immersion, and open porosity were found to be less than 2.5% for all the prepared matrices, whereas the compressive strength was in the range between 62.4 and 142.3 Kg.cm{sup -2}, depending on the composition of the prepared matrix. The prepared SPC matrices that characterized by X-ray diffraction (XRD) showed that the different added contaminants were stabilized during the solidification process during their reaction with sulfur and the organic polymer to form the corresponding metal sulfides. Toxicity Characteristic Leaching Procedure (TCLP), and the IAEA standard method have assessed the leachability of the prepared waste matrices. The TCLP results showed that most the concentration of the contaminants released were under their detection limit. The leach index for the investigated metals from the prepared SPC matrices was in the range of 9-11. The order of release of the investigated metals was Sr>Cs>Pb>Cr>Ce for the aliphatic polymer, and Sr>Cr>Pb>Cs>Ce for the aromatic one. The results obtained revealed a high performance for the prepared SPC matrices, as they are of low cost effect, highly available materials, and possessed good mechanical and leaching properties. Key Words: SPC/ Matrices/ Immobilization/ Wastes/ Leachability. (authors)« less
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Incorporating lower grade toxicity information into dose finding designs
Iasonos, Alexia; Zohar, Sarah; O’Quigley, John
2012-01-01
Background Toxicity grades underlie the definition of a dose limiting toxicity (DLT) but in the majority of phase I designs, the information contained in the individual grades is not used. Some authors have argued that it may be more appropriate to consider a polytomous rather than dichotomous response. Purpose We investigate whether the added information on individual grades can improve the operating characteristics of the Continual Reassessment Method (CRM). Methods We compare the original CRM design for a binary response with two stage CRM designs which make di erent use of lower-grade toxicity information via simulations. Specifically we study; a two-stage design that utilizes lower-grade toxicities in the first stage only, during the initial non model-based escalation, and two-stage designs where lower grades are used throughout the trial via explicit models. We postulate a model relating the rates of lower grade toxicities to the rate of DLTs, or assume the relative rates of low to high grade toxicities is unknown. The designs were compared in terms of accuracy, patient allocation and precision. Results Significant gains can be achieved when using grades in the first stage of a two-stage design. Otherwise, only modest improvements are seen when the information on grades is exploited via the use of explicit models, where the parameters are known precisely. CRM with some use of grade information, increases the number of patients treated at the MTD by approximately 5%. The additional information from lower grades can lead to a small increase in the precision of our estimate of the MTD. Limitations Our comparisons are not exhaustive and it would be worth studying other models and situations. Conclusions Although, the gains in performance were not as great as we had hoped, we observed no cases where the performance of CRM was poorer. Our recommendation is that investigators might consider using graded toxicities at the design stage. PMID:21835856
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Mixture toxicity of wood preservative products in the fish embryo toxicity test.
Coors, Anja; Dobrick, Jan; Möder, Monika; Kehrer, Anja
2012-06-01
Wood preservative products are used globally to protect wood from fungal decay and insects. We investigated the aquatic toxicity of five commercial wood preservative products, the biocidal active substances and some formulation additives contained therein, as well as six generic binary mixtures of the active substances in the fish embryo toxicity test (FET). Median lethal concentrations (LC50) of the single substances, the mixtures, and the products were estimated from concentration-response curves and corrected for concentrations measured in the test medium. The comparison of the experimentally observed mixture toxicity with the toxicity predicted by the concept of concentration addition (CA) showed less than twofold deviation for all binary mixtures of the active substances and for three of the biocidal products. A more than 60-fold underestimation of the toxicity of the fourth product by the CA prediction was detected and could be explained fully by the toxicity of one formulation additive, which had been labeled as a hazardous substance. The reason for the 4.6-fold underestimation of toxicity of the fifth product could not be explained unambiguously. Overall, the FET was found to be a suitable screening tool to verify whether the toxicity of formulated wood preservatives can reliably be predicted by CA. Applied as a quick and simple nonanimal screening test, the FET may support approaches of applying component-based mixture toxicity predictions within the environmental risk assessment of biocidal products, which is required according to European regulations. Copyright © 2012 SETAC.
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Reversible metronidazole-induced cerebellar toxicity in a multiple transplant recipient.
Graves, Tracey D; Condon, Marie; Loucaidou, Marina; Perry, Richard J
2009-10-15
Metronidazole-induced central nervous system (CNS) toxicity causes a spectrum of neurological symptoms including ataxia, encephalopathy and peripheral neuropathy. It is associated with characteristic MRI changes of high signal intensity in the dentate nuclei. Given the increasing use of metronidazole, it is import to recognise this drug as a cause of ataxia, as it is entirely reversible on drug withdrawal.
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Gold, Harris; Joback, Kevin; Geis, Steven; Bowman, George; Mericas, Dean; Corsi, Steven R.; Ferguson, Lee
2010-01-01
The current research was conducted to identify alternative aircraft and pavement deicer and anti-icer formulations with improved environmental characteristics compared to currently used commercial products (2007). The environmental characteristics of primary concern are the biochemical oxygen demand (BOD) and aquatic toxicity of the fully formulated products. Except when the distinction among products is necessary for clarity, “deicer” will refer to aircraft-deicing fluids (ADFs), aircraft anti-icing fluids (AAFs), and pavementdeicing materials (PDMs).
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Civilian exposure to toxic agents: emergency medical response.
Baker, David
2004-01-01
Civilian populations are at risk from exposure to toxic materials as a result of accidental or deliberate exposure. In addition to industrial hazards, toxic agents designed for use in warfare now are a potential hazard in everyday life through terrorist action. Civil emergency medical responders should be able to adapt their plans for dealing with casualties from hazardous materials (HazMat) to deal with the new threat. Chemical and biological warfare (CBW) and HazMat agents can be viewed as a continuous spectrum. Each of these hazards is characterized by qualities of toxicity, latency of action, persistency, and transmissibility. The incident and medical responses to release of any agent is determined by these characteristics. Chemical and biological wardare agents usually are classified as weapons of mass destruction, but strictly, they are agents of mass injury. The relationship between mass injury and major loss of life depends very much on the protection, organization, and emergency care provided. Detection of a civil toxic agent release where signs and symptoms in casualties may be the first indicator of exposure is different from the military situation where intelligence information and tuned detection systems generally will be available. It is important that emergency medical care should be given in the context of a specific action plan. Within an organized and protected perimeter, triage and decontamination (if the agent is persistent) can proceed while emergency medical care is provided at the same time. The provision of advanced life support (TOXALS) in this zone by protected and trained medical responders now is technically feasible using specially designed ventilation equipment. Leaving life support until after decontamination may have fatal consequences. Casualties from terrorist attacks also may suffer physical as well as toxic trauma and the medical response also should be capable of dealing with mixed injuries.
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NASA Astrophysics Data System (ADS)
Sirelkhatim, Amna; Mahmud, Shahrom; Seeni, Azman; Kaus, Noor Haida Mohd.; Sendi, Rabab
2014-10-01
In this study, we investigated physico-chemical properties of zinc oxide nanoparticles (ZnO NPs)-based discs and their toxicity on human cervical cancer HeLa cell lines. ZnO NPs (80 nm) were produced by the conventional ceramic processing method. FESEM analysis indicated dominant structure of nanorods with dimensions 100-500 nm in length, and 20-100 nm in diameter. The high content of ZnO nanorods in the discs probably played significant role in toxicity towards HeLa cells. Structural defects (oxygen vacancies and zinc/oxygen interstitials) were revealed by PL spectra peaks at 370-376 nm and 519-533 nm for the ZnO discs. The structural, optical and electrical properties of prepared sample have influenced the toxicological effects of ZnO discs towards HeLa cell lines via the generation of reactive oxygen species (ROS), internalization, membrane damage, and eventually cell death. The larger surface to volume area of the ZnO nanorods, combined with defects, stimulated enhanced toxicity via ROS generation hydrogen peroxide, hydroxyl radicals, and superoxide anion. The preliminary results confirmed the ZnO-disc toxicity on HeLa cells was significantly associated with the unique physicochemical properties of ZnO NPs and to our knowledge, this is the first cellular study for treatment of HeLa cells with ZnO discs made from 80 nm ZnO particles.
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TOXICITY CHARACTERIZATION PROCEDURES FOR ORGANIC TOXICANTS IN BULK SEDIMENTS
We have been pursuing development of toxicant characterization, isolation, and identification procedures for organic toxicants that can be applied in the context of 10-d solid-phase sediment tests measuring survival and growth of freshwater in the context of 10-d solid-phase sedi...
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Lipopolysaccharide-Induced Toxic Shock Syndrome in Rabbits.
Stach, Christopher S; Schlievert, Patrick M
2016-01-01
Enhancement of susceptibility to lipopolysaccharide (LPS; endotoxin) is a defining characteristic of Staphylococcus aureus superantigens. At the time of this publication, there are 24 identified staphylococcal superantigens (SAgs), some of which have yet to be fully characterized. Testing the capacity of superantigens to potentiate LPS sensitivity is essential to characterize the role of these proteins in disease development. Here we describe how to perform studies of the enhancement of LPS-induced toxic shock syndrome in rabbits. This protocol also provides information on a second important activity of superantigens: the production of fever.
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Sediment Toxicity Identification Evaluation
Approach combining chemical manipulations and aquatic toxicity testing, generally with whole organisms, to systematically characterize, identify and confirm toxic substances causing toxicity in whole sediments and sediment interstitial waters. The approach is divided into thre...
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Amyloid-linked cellular toxicity triggered by bacterial inclusion bodies
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gonzalez-Montalban, Nuria; Departament de Genetica i de Microbiologia, Universitat Autonoma de Barcelona, Bellaterra, 08193 Barcelona; Ciber de Bioingenieria, Biomateriales y Nanomedicina
The aggregation of proteins in the form of amyloid fibrils and plaques is the characteristic feature of some pathological conditions ranging from neurodegenerative disorders to systemic amyloidoses. The mechanisms by which the aggregation processes result in cell damage are under intense investigation but recent data indicate that prefibrillar aggregates are the most proximate mediators of toxicity rather than mature fibrils. Since it has been shown that prefibrillar forms of the nondisease-related misfolded proteins are highly toxic to cultured mammalian cells we have studied the cytoxicity associated to bacterial inclusion bodies that have been recently described as protein deposits presenting amyloid-likemore » structures. We have proved that bacterial inclusion bodies composed by a misfolding-prone {beta}-galactosidase fusion protein are clearly toxic for mammalian cells but the {beta}-galactosidase wild type enzyme forming more structured thermal aggregates does not impair cell viability, despite it also binds and enter into the cells. These results are in the line that the most cytotoxic aggregates are early prefibrilar assemblies but discard the hypothesis that the membrane destabilization is Key event to subsequent disruption of cellular processes, such as ion balance, oxidative state and the eventually cell death.« less
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A role for solvents in the toxicity of agricultural organophosphorus pesticides
Eddleston, Michael; Street, Jonathan M.; Self, Ian; Thompson, Adrian; King, Tim; Williams, Nicola; Naredo, Gregorio; Dissanayake, Kosala; Yu, Ly-Mee; Worek, Franz; John, Harald; Smith, Sionagh; Thiermann, Horst; Harris, John B.; Eddie Clutton, R.
2012-01-01
Organophosphorus (OP) insecticide self-poisoning is responsible for about one-quarter of global suicides. Treatment focuses on the fact that OP compounds inhibit acetylcholinesterase (AChE); however, AChE-reactivating drugs do not benefit poisoned humans. We therefore studied the role of solvent coformulants in OP toxicity in a novel minipig model of agricultural OP poisoning. Gottingen minipigs were orally poisoned with clinically relevant doses of agricultural emulsifiable concentrate (EC) dimethoate, dimethoate active ingredient (AI) alone, or solvents. Cardiorespiratory physiology and neuromuscular (NMJ) function, blood AChE activity, and arterial lactate concentration were monitored for 12 h to assess poisoning severity. Poisoning with agricultural dimethoate EC40, but not saline, caused respiratory arrest within 30 min, severe distributive shock and NMJ dysfunction, that was similar to human poisoning. Mean arterial lactate rose to 15.6 [SD 2.8] mM in poisoned pigs compared to 1.4 [0.4] in controls. Moderate toxicity resulted from poisoning with dimethoate AI alone, or the major solvent cyclohexanone. Combining dimethoate with cyclohexanone reproduced severe poisoning characteristic of agricultural dimethoate EC poisoning. A formulation without cyclohexanone showed less mammalian toxicity. These results indicate that solvents play a crucial role in dimethoate toxicity. Regulatory assessment of pesticide toxicity should include solvents as well as the AIs which currently dominate the assessment. Reformulation of OP insecticides to ensure that the agricultural product has lower mammalian toxicity could result in fewer deaths after suicidal ingestion and rapidly reduce global suicide rates. PMID:22365945
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Erten-Unal, M; Gelderloos, A B; Hughes, J S
1998-07-30
A Toxicity Reduction Evaluation (TRE) was conducted on the oily wastewater treatment plant (Plant) at a Naval Fuel Depot. The Plant treats ship and ballast wastes, berm water from fuel storage areas and wastes generated in the fuel reclamation plant utilizing physical/chemical treatment processes. In the first period of the project (Period I), the TRE included chemical characterization of the plant wastewaters, monitoring the final effluent for acute toxicity and a thorough evaluation of each treatment process and Plant operating procedures. Toxicity Identification Evaluation (TIE) procedures were performed as part of the overall TRE to characterize and identify possible sources of toxicity. Several difficulties were encountered because the effluent was saline, test organisms were marine species and toxicity was sporadic and unpredictable. The treatability approach utilizing enhancements, improved housekeeping, and operational changes produced substantial reductions in the acute toxicity of the final effluent. In the second period (Period II), additional acute toxicity testing and chemical characterization were performed through the Plant to assess the long-term effects of major unit process improvements for the removal of toxicity. The TIE procedures were also modified for saline wastewaters to focus on suspected class of toxicants such as surfactants. The TRE was successful in reducing acute toxicity of the final effluent through process improvements and operational modifications. The results indicated that the cause of toxicity was most likely due to combination of pollutants (matrix effect) rather than a single pollutant.
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DISTRIBUTED STRUCTURE-SEARCHABLE TOXICITY ...
The ability to assess the potential genotoxicity, carcinogenicity, or other toxicity of pharmaceutical or industrial chemicals based on chemical structure information is a highly coveted and shared goal of varied academic, commercial, and government regulatory groups. These diverse interests often employ different approaches and have different criteria and use for toxicity assessments, but they share a need for unrestricted access to existing public toxicity data linked with chemical structure information. Currently, there exists no central repository of toxicity information, commercial or public, that adequately meets the data requirements for flexible analogue searching, SAR model development, or building of chemical relational databases (CRD). The Distributed Structure-Searchable Toxicity (DSSTox) Public Database Network is being proposed as a community-supported, web-based effort to address these shared needs of the SAR and toxicology communities. The DSSTox project has the following major elements: 1) to adopt and encourage the use of a common standard file format (SDF) for public toxicity databases that includes chemical structure, text and property information, and that can easily be imported into available CRD applications; 2) to implement a distributed source approach, managed by a DSSTox Central Website, that will enable decentralized, free public access to structure-toxicity data files, and that will effectively link knowledgeable toxicity data s
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Muñoz, Alexandra; Costa, Max
2012-01-01
Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses - most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980’s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanism of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties. PMID:22206756
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Muñoz, Alexandra; Costa, Max, E-mail: Max.Costa@nyumc.org
Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses — most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanismmore » of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties.« less
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NASA Technical Reports Server (NTRS)
Macewen, J. D.; Vernot, E. H.
1971-01-01
The activities of the Toxic Hazards Research Unit (THRU) for the period of June 1970 through May 1971 reviewed. Modification of the animal exposure facilities primarily for improved human safety but also for experimental integrity and continuity are discussed. Acute toxicity experiments were conducted on hydrogen fluoride (HF), hydrogen chloride (HCl), nitrogen dioxide (NO2), and hydrogen cyanide (HCN) both singly and in combination with carbon dioxide (CO). Additional acute toxicity experiments were conducted on oxygen difluoride (OF2) and chlorine pentafluoride (ClF5). Subacute toxicity studies were conducted on methylisobutylketone and dichloromethane (methylene dichloride). The interim results of further chronic toxicity experiments on monomethylhydrazine (MMH) are also described.
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Development and application of freshwater sediment-toxicity benchmarks for currently used pesticides
Nowell, Lisa H.; Norman, Julia E.; Ingersoll, Christopher G.; Moran, Patrick W.
2016-01-01
/chemical characteristics of sediment, and uncertainty in TEB values. Additional evaluations of benchmarks in relation to sediment chemistry and toxicity are ongoing.
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Toxic Shock Syndrome: An Unusual Organism.
Young, Katie; Luni, Faraz Khan; Yoon, Youngsook
2016-07-01
Streptococcal toxic shock syndrome is a rapidly fatal disease causing hypotension with multi organ dysfunction (MODS) early in the course of infection, which by definition is caused by Group A streptococcus (GAS). We describe a case of Toxic Shock like Syndrome (TSLS) in which the causative organism was not a GAS. A 71-year-old woman with hepatitis C and primary biliary cirrhosis had sudden onset of slurred speech and left arm and facial numbness. She had bilateral erythematous macular rash present on the flanks and legs. She was started on empiric antibiotics but her condition rapidly deteriorated 6 hours after admission. During this time, the development of multiple large reddish-pink areas of ecchymosis with bullae on her lower extremities, flanks, and groin were noted. She also developed multiorgan dysfunction (MODS) with renal dysfunction, coagulopathy and liver involvement. Patient expired before surgery could be performed and the time from presentation to the time of death was 16 hours. The blood and bullae fluid cultures grew Streptococcus dysgalactiae equisimilis. Streptococcus dysgalactiae equisimilis is a rare cause of TSLS which typically affects elderly or immunocompromised patients and only a few cases have been described in the literature. Our patient met criteria for TSLS which caused rapid shock and MODS. We review the literature of the cases describing the clinical characteristics of TSLS cause by non-GAS. Group G Streptococci is a rare but lethal cause of streptococcal toxic shock syndrome. Copyright © 2016 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.
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Estimation of toxicity using the Toxicity Estimation Software Tool (TEST)
Tens of thousands of chemicals are currently in commerce, and hundreds more are introduced every year. Since experimental measurements of toxicity are extremely time consuming and expensive, it is imperative that alternative methods to estimate toxicity are developed.
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de Souza, Jonas A; Yap, Bonnie J; Wroblewski, Kristen; Blinder, Victoria; Araújo, Fabiana S; Hlubocky, Fay J; Nicholas, Lauren H; O'Connor, Jeremy M; Brockstein, Bruce; Ratain, Mark J; Daugherty, Christopher K; Cella, David
2017-02-01
Cancer and its treatment lead to increased financial distress for patients. To the authors' knowledge, to date, no standardized patient-reported outcome measure has been validated to assess this distress. Patients with AJCC Stage IV solid tumors receiving chemotherapy for at least 2 months were recruited. Financial toxicity was measured by the COmprehensive Score for financial Toxicity (COST) measure. The authors collected data regarding patient characteristics, clinical trial participation, health care use, willingness to discuss costs, psychological distress (Brief Profile of Mood States [POMS]), and health-related quality of life (HRQOL) as measured by the Functional Assessment of Cancer Therapy: General (FACT-G) and the European Organization for Research and Treatment of Cancer (EORTC) QOL questionnaires. Test-retest reliability, internal consistency, and validity of the COST measure were assessed using standard-scale construction techniques. Associations between the resulting factors and other variables were assessed using multivariable analyses. A total of 375 patients with advanced cancer were approached, 233 of whom (62.1%) agreed to participate. The COST measure demonstrated high internal consistency and test-retest reliability. Factor analyses revealed a coherent, single, latent variable (financial toxicity). COST values were found to be correlated with income (correlation coefficient [r] = 0.28; P<.001), psychosocial distress (r = -0.26; P<.001), and HRQOL, as measured by the FACT-G (r = 0.42; P<.001) and by the EORTC QOL instruments (r = 0.33; P<.001). Independent factors found to be associated with financial toxicity were race (P = .04), employment status (P<.001), income (P = .003), number of inpatient admissions (P = .01), and psychological distress (P = .003). Willingness to discuss costs was not found to be associated with the degree of financial distress (P = .49). The COST measure demonstrated reliability and
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Children's Ability to Recognise Toxic and Non-Toxic Fruits
ERIC Educational Resources Information Center
Fancovicova, Jana; Prokop, Pavol
2011-01-01
Children's ability to identify common plants is a necessary prerequisite for learning botany. However, recent work has shown that children lack positive attitudes toward plants and are unable to identify them. We examined children's (aged 10-17) ability to discriminate between common toxic and non-toxic plants and their mature fruits presented in…
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NASA Technical Reports Server (NTRS)
Junod, T. L.
1979-01-01
Handbook, published in conjunction with Toxic Substances Alert Program at NASA Lewis Research Center, profiles 187 toxic chemicals in their relatively pure states and include 27 known or suspected carcinogens.
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Toxicity evaluation and prediction of toxic chemicals on activated sludge system.
Cai, Bijing; Xie, Li; Yang, Dianhai; Arcangeli, Jean-Pierre
2010-05-15
The gaps of data for evaluating toxicity of new or overloaded organic chemicals on activated sludge system resulted in the requirements for methodology of toxicity estimation. In this study, 24 aromatic chemicals typically existed in the industrial wastewater were selected and classified into three groups of benzenes, phenols and anilines. Their toxicity on activated sludge was then investigated. Two indexes of IC(50-M) and IC(50-S) were determined respectively from the respiration rates of activated sludge with different toxicant concentration at mid-term (24h) and short-term (30min) time intervals. Experimental results showed that the group of benzenes was the most toxic, followed by the groups of phenols and anilines. The values of IC(50-M) of the tested chemicals were higher than those of IC(50-S). In addition, quantitative structure-activity relationships (QSARs) models developed from IC(50-M) were more stable and accurate than those of IC(50-S). The multiple linear models based on molecular descriptors and K(ow) presented better reliability than single linear models based on K(ow). Among these molecular descriptors, E(lumo) was the most important impact factor for evaluation of mid-term toxicity. Copyright (c) 2009 Elsevier B.V. All rights reserved.
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Pharmacokinetic and pharmacogenetic markers of irinotecan toxicity.
Hahn, Roberta Zilles; Antunes, Marina Venzon; Verza, Simone Gasparin; Perassolo, Magda Susana; Suyenaga, Edna Sayuri; Schwartsmann, Gilberto; Linden, Rafael
2018-06-22
Irinotecan (IRI) is a widely used chemotherapeutic drug, mostly used for first-line treatment of colorectal and pancreatic cancer. IRI doses are usually established based on patient's body surface area, an approach associated with large inter-individual variability in drug exposure and high incidence of severe toxicity. Toxic and therapeutic effects of IRI are also due to its active metabolite SN-38, reported to be up to 100 times more cytotoxic than IRI. SN-38 is detoxified by the formation of SN-38 glucuronide, through UGT1A1. Genetic polymorphisms in the UGT1A1 gene are associated to higher exposures to SN-38 and severe toxicity. Pharmacokinetic models to describe IRI and SN-38 kinetic profiles are available, with few studies exploring pharmacokinetic and pharmacogenetic-based dose individualization. The aim of this manuscript is to review the available evidence supporting pharmacogenetic and pharmacokinetic dose individualization of IRI in order to reduce the occurrence of severe toxicity during cancer treatment. The PubMed database was searched, considering papers published in the period from 1995-2017, using the keywords irinotecan, pharmacogenetics, metabolic genotyping, dose individualization, therapeutic drug monitoring, pharmacokinetics and pharmacodynamics, either alone or in combination, with original papers being selected based on the presence of relevant data. The findings of this review confirm the importance of considering individual patient characteristics to select IRI doses. Currently, the most straightforward approach for IRI dose individualization is UGT1A1 genotyping. However, this strategy is sub-optimal due to several other genetic and environmental contributions to the variable pharmacokinetics of IRI and its active metabolite. The use of dried blood spot sampling could allow the clinical application of complex sampling for the clinical use of limited sampling and population pharmacokinetic models for IRI doses individualization. Copyright
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhu, Lijun; Wu, Jinjun; Zhao, Min
Aconitine (AC) is the primary bioactive/toxic alkaloid in plants of the Aconitum species. Our previous study demonstrated that Mdr1 was involved in efflux of AC. However, the mechanism by which Mdr1 regulates the efficacy/toxicity of AC in vivo remains unclear. The present study aimed to determine the effects of Mdr1a on the efficacy/toxicity and pharmacokinetics of AC in wild-type and Mdr1a{sup −/−} FVB mice. After oral administration of AC, significantly higher analgesic effect was observed in Mdr1a{sup −/−} mice (49% to 105%) compared to wild-type mice (P < 0.05). The levels of s100-β protein and creatine kinase, which indicate cerebralmore » and myocardial damage, respectively, were also significantly increased (P < 0.05) in Mdr1a{sup −/−} mice. Histopathological examination revealed that the Mdr1a{sup −/−} mice suffered from evident cerebral and myocardial damages, but the wild-type mice did not. These findings suggested that Mdr1a deficiency significantly promoted the analgesic effect of AC and exacerbated its toxicity. Pharmacokinetic experiments showed that T{sub 1/2} of AC in the Mdr1a{sup −/−} mice was significantly higher (from 87% to 300%) than that in wild-type mice (P < 0.05). The distribution of AC in the brain of Mdr1a{sup −/−} mice was 2- to 32-fold higher than that in the brains of wild-type mice (P < 0.05). Toxic reactions were more severe in Mdr1a{sup −/−} mice compared to wild-type mice. In conclusion, Mdr1a deficiency significantly enhanced the analgesic effect of AC and exacerbated its toxicity by upregulating its distribution to the brain and decreasing its plasma elimination rate. Thus, Mdr1a dysfunction may cause severe AC poisoning. - Highlights: • The efficacy and toxicity of aconitine were significantly enhanced in Mdr1a{sup −/−} mice. • The distribution of aconitine to the brain was remarkably increased in Mdr1a{sup −/−} mice. • The elimination rate of aconitine was significantly decreased
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Toxicity assessment and geochemical model of chromium leaching from AOD slag.
Liu, Bao; Li, Junguo; Zeng, Yanan; Wang, Ziming
2016-02-01
AOD (Argon Oxygen Decarburization) slag is a by-product of the stainless steel refining process. The leaching toxicity of chromium from AOD slag cannot be ignored in the recycling process of the AOD slag. To assess the leaching toxicity of the AOD slag, batch leaching tests have been performed. PHREEQC simulations combined with FactSage were carried out based on the detailed mineralogical analysis and petrophysical data. Moreover, Pourbaix diagram of the Cr-H2O system was protracted by HSC 5.0 software to explore the chromium speciation in leachates. It was found that AOD slag leachate is an alkaline and reductive solution. The Pourbaix diagram of the Cr-H2O system indicated that trivalent chromium, such as Cr(OH)4(-), is the major chromium species in the experimental Eh-pH region considered. However, toxic hexavalent chromium was released with maximum concentrations of 30 µg L(-1) and 18 µg L(-1) at L/S 10 and 100, respectively, during the earlier leaching stage. It concluded that the AOD slag possessed a certain leaching toxicity. After 10 d of leaching, trivalent chromium was the dominant species in the leachates, which corresponded to the results of PHREEQC simulation. Leaching toxicity of AOD slag is based on the chromium speciation and its transformation. Great attention should be focused on such factors as aging, crystal form of chromium-enriched minerals, and electrochemical characteristics of the leachates. Copyright © 2015 Elsevier Ltd. All rights reserved.
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James, D; Adams, R D; Spears, R; Cooper, G; Lupton, D J; Thompson, J P
2010-01-01
Objective To describe the patterns and clinical features of toxicity related to recreational use of mephedrone and other cathinones in the UK using data collected by the National Poisons Information Service (NPIS). Methods The number of accesses to TOXBASE, the NPIS online poisons information database, details of consecutive cases uploaded onto TOXBASE and the number and details of telephone enquiries made to the NPIS by health professionals in the UK were collected for the period March 2009 to February 2010. Results Over the year of study there were 2901 TOXBASE accesses and 188 telephone enquiries relating to cathinones, the majority relating to mephedrone (TOXBASE 1664, telephone 157), with a month-on-month increase in numbers. In 131 telephone enquiries concerning mephedrone, alone or in combination with alcohol, common clinical features reported included agitation or aggression (n=32, 24%, 95% CI 18% to 33%), tachycardia (n=29, 22%, 95% CI 16% to 30%), confusion or psychosis (n=18, 14%, 95% CI 9% to 21%), chest pain (n=17, 13%, 95% CI 8% to 20%), nausea (n=15, 11%, 95% CI 7% to 18%), palpitations (n=14, 11%, 95% CI 6% to 18%), peripheral vasoconstriction (n=10, 8%, 95% CI 4% to 14%) and headache (n=7, 5%, 95% CI 2% to 11%). Convulsions were reported in four cases (3%, 95% CI 1% to 8%). One exposed person died following cardiac arrest (1%, 95% CI 0% to 4%), although subsequent investigation suggested that mephedrone was not responsible. Conclusions Toxicity associated with recreational mephedrone use is increasingly common in the UK. Sympathomimetic adverse effects are common and severe effects are also reported. Structured data collected by the NPIS may be of use in identifying trends in poisoning and in establishing toxidromes for new drugs of abuse. PMID:20798084
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Random Forests to Predict Rectal Toxicity Following Prostate Cancer Radiation Therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ospina, Juan D.; INSERM, U1099, Rennes; Escuela de Estadística, Universidad Nacional de Colombia Sede Medellín, Medellín
2014-08-01
Purpose: To propose a random forest normal tissue complication probability (RF-NTCP) model to predict late rectal toxicity following prostate cancer radiation therapy, and to compare its performance to that of classic NTCP models. Methods and Materials: Clinical data and dose-volume histograms (DVH) were collected from 261 patients who received 3-dimensional conformal radiation therapy for prostate cancer with at least 5 years of follow-up. The series was split 1000 times into training and validation cohorts. A RF was trained to predict the risk of 5-year overall rectal toxicity and bleeding. Parameters of the Lyman-Kutcher-Burman (LKB) model were identified and a logistic regression modelmore » was fit. The performance of all the models was assessed by computing the area under the receiving operating characteristic curve (AUC). Results: The 5-year grade ≥2 overall rectal toxicity and grade ≥1 and grade ≥2 rectal bleeding rates were 16%, 25%, and 10%, respectively. Predictive capabilities were obtained using the RF-NTCP model for all 3 toxicity endpoints, including both the training and validation cohorts. The age and use of anticoagulants were found to be predictors of rectal bleeding. The AUC for RF-NTCP ranged from 0.66 to 0.76, depending on the toxicity endpoint. The AUC values for the LKB-NTCP were statistically significantly inferior, ranging from 0.62 to 0.69. Conclusions: The RF-NTCP model may be a useful new tool in predicting late rectal toxicity, including variables other than DVH, and thus appears as a strong competitor to classic NTCP models.« less
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... toxic shock syndrome results from toxins produced by Staphylococcus aureus (staph) bacteria, but the condition may also be ... a skin or wound infection. Causes Most commonly, Staphylococcus aureus (staph) bacteria cause toxic shock syndrome. The syndrome ...
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Mondal, Ananya; Das, Subhasish; Sah, Rajesh Kumar; Bhattacharyya, Pradip; Bhattacharya, Satya Sundar
2017-12-31
Coal fired brick kiln factories generate significant of brick kiln bottom ash (BKBA) that contaminate soil and water environments of areas near the dumping sites through leaching of toxic metals (Pb, Cr, Cd, Zn, Mn, and Cu). However, characteristics and environmental effects of BKBAs are yet unknown. We collected BKBA samples from 32 strategic locations of two rapidly developing States (West Bengal and Assam) of India. Scanning electron microscope images indicated spherical and granular structures of BKBAs produced in West Bengal (WBKBA) and Assam (ABKBA) respectively; while energy dispersive spectroscopy and analytical assessments confirmed substantial occurrence of total organic C and nutrient elements (N, P, K, Ca, Mg, and S) in both the BKBAs. FTIR analysis revealed greater predominance of organic matter in ABKBAs than WBKBAs. Occurrence of toxic metals (Cd, Cr, Pb, Zn, Mn, and Cu) was higher in ABKBAs than in WBKBAs; while organic and residual fractions of metals were highly predominant in most of the BKBAs. Principal component analysis showed that metal contents and pH were the major distinguishing characteristics of the BKBAs generated in the two different environmental locations. Human health risk associated with BKBAs generated in Assam is of significant concern. Finally, geo-statistical tools enabled to predict the spatial distribution patterns of toxic metals contributed by the BKBAs in Assam and West Bengal respectively. Assessment of contamination index, geo-accumulation index, and ecological risk index revealed some BKBAs to be more toxic than others. Copyright © 2017. Published by Elsevier B.V.
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Applicability of ambient toxicity testing to national or regional water-quality assessment
Elder, J.F.
1989-01-01
Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water quality assessments. These purposes may include identification that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. A wide variety of toxicity test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the full selections made relative to four characteristics: (1) test species, (2) endpoints (acute or chronic), (3) test enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity test approachs vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing is more likely to meet these needs than are the procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depend on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because of the fact that most toxicants tend to accumulate in sediments, and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water quality assessments. They are relatively rapid and simple, and more importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants and their sensitivities vary as
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In vitro toxicity analysis of nanoscale aluminum: Particle size and shape effects
NASA Astrophysics Data System (ADS)
Palazuelos Jorganes, Maria
2007-12-01
Nanostructured materials promise to revolutionize many key areas of science and technology. As our ability to manipulate matter at the nanoscale increases, there is a need to assess the effects of these materials on human health and the environment. Materials at the nanoscale are interesting and useful because they possess properties that are different from the equivalent bulk or molecular scale. These same properties can make toxicological profiles very different from those of the same materials on a different scale. There is a rising consensus that toxicity analysis of nanomaterials should start from a thorough physicochemical characterization of the materials under investigation in order to be able to establish a proper correlation between the nanoparticles characteristics and their effects and behavior in physiological environments. This research is a clear example of the necessity of comprehensive studies when investigating the toxicity of nanomaterials. Aluminum nanoparticles are being extensively used for their very unique energetic properties. These materials offer a very promising market that is fostering many startup companies which are expected to consolidate on strong technological positions. Aluminum is generally recognized as a non-toxic material to humans and it is widely used for applications which imply direct human contact. The effect of aluminum nanoparticles in human health is still an unknown. My research consisted of an in vitro toxicity screening of aluminum materials from nano to micron size, including spherical irregularly shaped particles. Several issues relating to size, shape, detection and characterization of nanoparticles in the different environments relevant to in vitro toxicity analysis were addressed and suitable protocols were developed. Lung human epithelial cells were exposed to different concentrations of these materials and the effects were analyzed by means of various toxicity tests. Some of the materials investigated caused
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Electronic Cigarette Toxicity.
Payne, J Drew; Michaels, David; Orellana-Barrios, Menfil; Nugent, Kenneth
2017-04-01
Electronic cigarettes (e-cigarettes) are often advertised as a healthier product when compared with traditional cigarettes. Currently, there are limited data to support this and only a threat of federal regulation from the US Food and Drug Administration. Calls to poison control centers about e-cigarette toxicity, especially in children, and case reports of toxic exposures have increased over the past 3 years. This research letter reports the frequency of hazardous exposures to e-cigarettes and characterizes the reported adverse health effects associated with e-cigarette toxicity.
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Pulmonary toxicity of manufactured nanoparticles
NASA Astrophysics Data System (ADS)
Peebles, Brian Christopher
for occupational health. Permissible exposure limits to micrometer-size particulate matter in the workplace are in place, but current limits do not specifically address the role of surface chemistry and the potentially higher toxicity of nanomaterials. The size, agglomeration characteristics, and surface chemistry of carbon nanoparticles are being studied and manipulated to explore the causes of their toxicity. Inflammatory response and cytotoxicity following exposure of human and murine macrophages to nanoparticles are being employed as indicators of the ability of particles to cause respiratory harm. The results are expected to lead to more effective standards for nanomaterial exposure in the workplace and pathways to toxicity mitigation.
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Toxicity and bioaccumulation of cadmium in experimental cultures of Duckweed, Lemna polyrrhiza
DOE Office of Scientific and Technical Information (OSTI.GOV)
Charpentier, S.; Garnier, J.; Flaugnatti, R.
1987-06-01
Knowledge of the mechanism of Itai-Itai disease aided the research concerning the bioaccumulation of heavy metals in plants and aquatic organisms. Because of their characteristics, lemnaceae can be considered as an interesting experimental material. Their small size, rapid growth and vegetative reproduction permitted us to obtain experimental cultures and to study the effect of cadmium: toxicity and bioaccumulation. The species Lemna polyrrhiza having a very voluminous root system, was used in this work. The effects of cadmium chloride (Cd Cl/sub 2/-2.5 H/sub 2/O) and Cadmium sulfate (3 Cd SO/sub 4/-8H/sub 2/O) were compared. The toxicity effect was approached by themore » numeration of plants.« less
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Metal Nanomaterial Toxicity Variations Within the Vascular System
Abukabda, Alaeddin B.; Stapleton, Phoebe A.; Nurkiewicz, Timothy R.
2016-01-01
Engineered nanomaterials (ENM) are anthropogenic materials with at least one dimension less than 100 nm. Their ubiquitous employment in biomedical and industrial applications in the absence of full toxicological assessments raises significant concerns over their safety on human health. This is a significant concern, especially for metal and metal oxide ENM as they may possess the greatest potential to impair human health. A large body of literature has developed that reflects adverse systemic effects associated with exposure to these materials, but an integrated mechanistic framework for how ENM exposure influences morbidity remains elusive. This may be due in large part to the tremendous diversity of existing ENM and the rate at which novel ENM are produced. In this review, the influence of specific ENM physicochemical characteristics and hemodynamic factors on cardiovascular toxicity are discussed. Additionally, the toxicity of metallic, and metal oxide ENM is presented in the context of the cardiovascular system and its discrete anatomical and functional components. Finally, future directions and understudied topics are presented. While it is clear that the nanotechnology boom has increased our interest in ENM toxicity, it is also evident that the field of cardiovascular nanotoxicology remains in its infancy and continued, expansive research is necessary in order to determine the mechanisms via which ENM exposure contributes to cardiovascular morbidity. PMID:27686080
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The reference envelope (RE) has been proposed as an alternative approach to assess sediment toxicity to overcome limitations imposed by the use of control sediments including differences in non-contaminant characteristics and low statistical power when many test sediments are com...
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Toxicity of trace element and salinity mixtures to striped bass (Morone saxatilis) and Daphnia magna
Dwyer, F.J.; Burch, S.A.; Ingersoll, C.G.; Hunn, J.B.
1992-01-01
Acute toxicity tests with reconstituted water were conducted to investigate the relationship between water hardness, salinity, and a mixture of trace elements found in irrigation drain waters entering Stillwater Wildlife Management Area (SWMA), near Fallon, Nevada. The SWMA has been the site of many fish kills in recent years, and previous toxicity studies indicated that one drain water, Pintail Bay, was acutely toxic to organisms acclimated or cultured in fresh water or salt water. This toxicity could reflect both the ionic composition of this saline water and the presence of trace elements. The lowest water salinity tested with Daphnia magna was near the upper salinity tolerance of these organisms; therefore, we were unable to differentiate between the toxic effects of ion composition and those of trace elements. In toxicity tests conducted with striped bass (Morone saxatilis), we found that the extent to which salinity was lethal to striped bass depended on the ion composition of that salinity. Survival of striped bass increased as hardness increased. In addition, a trace element mixture was toxic to striped bass, even though the concentrations of individual elements were below expected acutely lethal concentrations. Although salinity is an important water quality characteristic, the ionic composition of the water must be considered when one assesses the hazard of irrigation drain waters to aquatic organisms.
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Stogner, S W; Payne, D K
1992-12-01
The objective of this article is to provide an overview of the biochemistry of oxygen metabolism, including the formation of free radicals and the role of endogenous antioxidants. Pathophysiologic correlates underlying the clinical manifestations of oxygen toxicity are reviewed and management strategies are outlined. References from basic science and clinical journals were selected from the authors' files and from a search of a computerized database of the biomedical literature. Articles selected for review included both historical and current literature concerning the biochemistry and pathophysiology of oxygen toxicity in animals and humans. The benefits of oxygen therapy have been known for many years; however, its potential toxicity has not been recognized until the last two decades. The lungs, the eyes, and, under certain conditions, the central nervous system are the organs most affected by prolonged exposure to hyperoxic environments. Free radical formation during cellular metabolism under hyperoxic conditions is recognized as the biochemical basis of oxygen injury to cells and organs. Endogenous antioxidants are a primary means of detoxifying reactive oxygen species and preventing hyperoxia-induced cellular damage. When this defense fails or is overwhelmed by the excessive production of hyperoxia-induced free-radical species, distinctive morphologic changes occur at the cellular level. The amount of hyperoxia required to cause cellular damage and the time course of these changes vary from species to species and from individual to individual within the same species. Age, nutritional status, presence of underlying diseases, and certain drugs may influence the development of oxygen toxicity. There is currently no reliably effective drug for preventing or delaying the development of oxygen toxicity in humans. Use of the lowest effective oxygen concentration, the avoidance of certain drugs, and attention to nutritional and metabolic factors remain the best means
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40 CFR 80.915 - How are the baseline toxics value and baseline toxics volume determined?
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How are the baseline toxics value and... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Toxics Baseline Determination § 80.915 How are the baseline toxics value and baseline toxics volume determined? (a...
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40 CFR 80.915 - How are the baseline toxics value and baseline toxics volume determined?
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 16 2011-07-01 2011-07-01 false How are the baseline toxics value and... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Toxics Baseline Determination § 80.915 How are the baseline toxics value and baseline toxics volume determined? (a...
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Development of a general baseline toxicity QSAR model for the fish embryo acute toxicity test.
Klüver, Nils; Vogs, Carolina; Altenburger, Rolf; Escher, Beate I; Scholz, Stefan
2016-12-01
Fish embryos have become a popular model in ecotoxicology and toxicology. The fish embryo acute toxicity test (FET) with the zebrafish embryo was recently adopted by the OECD as technical guideline TG 236 and a large database of concentrations causing 50% lethality (LC 50 ) is available in the literature. Quantitative Structure-Activity Relationships (QSARs) of baseline toxicity (also called narcosis) are helpful to estimate the minimum toxicity of chemicals to be tested and to identify excess toxicity in existing data sets. Here, we analyzed an existing fish embryo toxicity database and established a QSAR for fish embryo LC 50 using chemicals that were independently classified to act according to the non-specific mode of action of baseline toxicity. The octanol-water partition coefficient K ow is commonly applied to discriminate between non-polar and polar narcotics. Replacing the K ow by the liposome-water partition coefficient K lipw yielded a common QSAR for polar and non-polar baseline toxicants. This developed baseline toxicity QSAR was applied to compare the final mode of action (MOA) assignment of 132 chemicals. Further, we included the analysis of internal lethal concentration (ILC 50 ) and chemical activity (La 50 ) as complementary approaches to evaluate the robustness of the FET baseline toxicity. The analysis of the FET dataset revealed that specifically acting and reactive chemicals converged towards the baseline toxicity QSAR with increasing hydrophobicity. The developed FET baseline toxicity QSAR can be used to identify specifically acting or reactive compounds by determination of the toxic ratio and in combination with appropriate endpoints to infer the MOA for chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Staples, C A; Murphy, S R; McLaughlin, J E; Leung, H W; Cascieri, T C; Farr, C H
2000-01-01
Acrylic acid, methyl acrylate, ethyl acrylate, and butyl acrylate are commercially important and widely used materials. This paper reports the results of a series of fate and aquatic toxicity studies. The mobility in soil of acrylic acid and its esters ranged from 'medium' to 'very high'. Calculated bioconcentration factors ranged from 1 to 37, suggesting a low bioconcentration potential. Acrylic acid and methyl acrylate showed limited biodegradability in the five day biochemical oxygen demand (BOD5) test, while ethyl acrylate and butyl acrylate were degraded easily (77% and 56%, respectively). Using the OECD method 301D 28-d closed bottle test, degradability for acrylic acid was 81% at 28 days, while the acrylic esters ranged from 57% to 60%. Acrylic acid degraded rapidly to carbon dioxide in soil (t1/2 < 1 day). Toxicity tests were conducted using freshwater and marine fish, invertebrates, and algae. Acrylic acid effect concentrations for fish and invertebrates ranged from 27 to 236 mg/l. Effect concentrations (LC50 or EC50) for fish and invertebrates using methyl acrylate, ethyl acrylate, and butyl acrylate ranged from 1.1 to 8.2 mg/l. The chronic MATC for acrylic acid with Daphnia magna was 27 mg/l based on length and young produced per adult reproduction day and for ethyl acrylate was 0.29 mg/l based on both the reproductive and growth endpoints. Overall these studies show that acrylic acid and the acrylic esters studied can rapidly biodegrade, have a low potential for persistence or bioaccumulation in the environment, and have low to moderate toxicity.
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Sediment toxicity testing has become a fundamental component of regulatory frameworks for assessing the risks posed by contaminated sediments and for development of chemical sediment quality guidelines. Over the past two decades, sediment toxicity testing methods have advanced co...
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Huang Jiayi; Robertson, John M., E-mail: jrobertson@beaumont.edu; Ye Hong
2012-07-15
Purpose: To identify dosimetric predictors for the development of gastrointestinal (GI) toxicity in patients with locally advanced pancreatic adenocarcinoma (LAPC) treated with concurrent full-dose gemcitabine and radiotherapy (GemRT). Methods and Materials: From June 2002 to June 2009, 46 LAPC patients treated with definitive GemRT were retrospectively analyzed. The stomach and duodenum were retrospectively contoured separately to determine their dose-volume histogram (DVH) parameters. GI toxicity was defined as Grade 3 or higher GI toxicity. The follow-up time was calculated from the start of RT to the date of death or last contact. Univariate analysis (UVA) and multivariate analysis (MVA) using Kaplan-Meiermore » and Cox regression models were performed to identify risk factors associated with GI toxicity. The receiver operating characteristic curve and the area under the receiver operating characteristic curve (AUC) were used to determine the best DVH parameter to predict for GI toxicity. Results: Of the patients, 28 (61%) received concurrent gemcitabine alone, and 18 (39%) had concurrent gemcitabine with daily erlotinib. On UVA, only the V{sub 20Gy} to V{sub 35Gy} of duodenum were significantly associated with GI toxicity (all p {<=} 0.05). On MVA, the V{sub 25Gy} of duodenum and the use of erlotinib were independent risk factors for GI toxicity (p = 0.006 and 0.02, respectively). For the entire cohort, the V{sub 25Gy} of duodenum is the best predictor for GI toxicity (AUC = 0.717), and the 12-month GI toxicity rate was 8% vs. 48% for V{sub 25Gy} {<=} 45% and V{sub 25Gy} > 45%, respectively (p = 0.03). However, excluding the erlotinib group, the V{sub 35Gy} is the best predictor (AUC = 0.725), and the 12-month GI toxicity rate was 0% vs. 41% for V{sub 35Gy} {<=} 20% and V{sub 35Gy} > 20%, respectively (p = 0.04). Conclusions: DVH parameters of duodenum may predict Grade 3 GI toxicity after GemRT for LAPC. Concurrent use of erlotinib during GemRT may increase
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Yellow phosphorus process to convert toxic chemicals to non-toxic products
Chang, S.G.
1994-07-26
The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O[sub 3], PO, PO[sub 2], etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like. 20 figs.
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Yellow phosphorus process to convert toxic chemicals to non-toxic products
Chang, Shih-Ger
1994-01-01
The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O.sub.3, PO, PO.sub.2, etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like.
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Mbah, Chamberlain; De Ruyck, Kim; De Schrijver, Silke; De Sutter, Charlotte; Schiettecatte, Kimberly; Monten, Chris; Paelinck, Leen; De Neve, Wilfried; Thierens, Hubert; West, Catharine; Amorim, Gustavo; Thas, Olivier; Veldeman, Liv
2018-05-01
Evaluation of patient characteristics inducing toxicity in breast radiotherapy, using simultaneous modeling of multiple endpoints. In 269 early-stage breast cancer patients treated with whole-breast irradiation (WBI) after breast-conserving surgery, toxicity was scored, based on five dichotomized endpoints. Five logistic regression models were fitted, one for each endpoint and the effect sizes of all variables were estimated using maximum likelihood (MLE). The MLEs are improved with James-Stein estimates (JSEs). The method combines all the MLEs, obtained for the same variable but from different endpoints. Misclassification errors were computed using MLE- and JSE-based prediction models. For associations, p-values from the sum of squares of MLEs were compared with p-values from the Standardized Total Average Toxicity (STAT) Score. With JSEs, 19 highest ranked variables were predictive of the five different endpoints. Important variables increasing radiation-induced toxicity were chemotherapy, age, SATB2 rs2881208 SNP and nodal irradiation. Treatment position (prone position) was most protective and ranked eighth. Overall, the misclassification errors were 45% and 34% for the MLE- and JSE-based models, respectively. p-Values from the sum of squares of MLEs and p-values from STAT score led to very similar conclusions, except for the variables nodal irradiation and treatment position, for which STAT p-values suggested an association with radiosensitivity, whereas p-values from the sum of squares indicated no association. Breast volume was ranked as the most significant variable in both strategies. The James-Stein estimator was used for selecting variables that are predictive for multiple toxicity endpoints. With this estimator, 19 variables were predictive for all toxicities of which four were significantly associated with overall radiosensitivity. JSEs led to almost 25% reduction in the misclassification error rate compared to conventional MLEs. Finally, patient
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Thermal immobilization of Cr, Cu and Zn of galvanizing wastes in the presence of clay and fly ash.
Singh, I B; Chaturvedi, K; Yegneswaran, A H
2007-07-01
In the present investigation thermal treatment of galvanizing waste with clay and fly ash has been carried out to immobilize Cr, Zn, Cu and other metals of the waste at temperature range 850 degrees C to 950 degrees C. Leaching of the metals from the waste and solidified product was analyzed using toxic characteristic leaching procedure (TCLP). Results indicated that the composition of waste and clay treatment temperature are the key factors in determining the stability of solidified product. After heating at 950 degrees C, the solidified specimens of 10% waste with clay have shown comparatively a high compressive strength and less water absorption. However, a decrease in compressive strength and increase in water absorption were noticed after addition of 15% of waste with clay. The leachability of all the metals present in the waste was found to reduce considerably with the increase of treatment temperature. In the case of Cr and Zn, their leachabilty was found at unacceptable levels from the treated product obtained after heating at 850 degrees C However, their leachability was reduced significantly within an acceptable level after treatment at 950 degrees C. The thermal treatment has shown an increase of re-oxidation trend of Cr (III) to Cr (VI) up to 900 degrees C of heating and this trend became almost zero after heating at 950 degrees C. Addition of fly ash did not show any improvement in strength, durability and leachability of metals from the thermally treated product. X-ray diffraction (XRD) analysis of the product confirmed the presence of mixed phases of oxides of toxic metals.
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Lyu, Honghong; Zhao, Hang; Tang, Jingchun; Gong, Yanyan; Huang, Yao; Wu, Qihang; Gao, Bin
2018-03-01
Biochar supported carboxymethyl cellulose (CMC)-stabilized nanoscale iron sulfide (FeS) composite (CMC-FeS@biochar) was prepared and tested for immobilization of hexavalent chromium Cr(VI) in soil. Results of UV-vis and transmission electron microscopy (TEM) showed that the backbone of biochar suppressed the aggregation of FeS, resulting in smaller particle size and more sorption sites than bare FeS. The composite at a dosage of 2.5 mg per gram soil displayed an enhanced Cr(VI) immobilization efficiency (a 94.7% reduction in the toxicity characteristic leaching procedure (TCLP) based leachability and a 95.6% reduction in the CaCl 2 extraction) compared to plain biochar and bare FeS. Sequential extraction procedure (SEP) and X-ray photoelectron spectroscopy (XPS) analysis suggested that CMC-FeS@biochar promoted the conversion of more accessible Cr (exchangeable and carbonate-bound fractions) into the less accessible forms (iron-manganese oxides-bound, organic material-bound, and residual fractions) to reduce the toxicity of Cr(VI) and that surface sorption and reduction were dominant mechanisms for Cr(VI) immobilization. CMC-FeS@biochar greatly reduced the bioavailability of Cr(VI) to wheat and earthworms (Eisenia fetida). Moreover, the application of CMC-FeS@biochar enhanced soil organic matter content and microbial activity. This work highlighted the potential of CMC-FeS@biochar composite as a low-cost, "green", and effective amendment for immobilizing Cr(VI) in contaminated soils and improving soil properties. Copyright © 2017 Elsevier Ltd. All rights reserved.
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SAR STUDY OF NASAL TOXICITY: LESSONS FOR MODELING SMALL TOXICITY DATASETS
Most toxicity data, particularly from whole animal bioassays, are generated without the needs or capabilities of structure-activity relationship (SAR) modeling in mind. Some toxicity endpoints have been of sufficient regulatory concern to warrant large scale testing efforts (e.g....
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Validating potential toxicity assays to assess petroleum hydrocarbon toxicity in polar soil.
Harvey, Alexis Nadine; Snape, Ian; Siciliano, Steven Douglas
2012-02-01
Potential microbial activities are commonly used to assess soil toxicity of petroleum hydrocarbons (PHC) and are assumed to be a surrogate for microbial activity within the soil ecosystem. However, this assumption needs to be evaluated for frozen soil, in which microbial activity is limited by liquid water (θ(liquid)). Influence of θ(liquid) on in situ toxicity was evaluated and compared to the toxicity endpoints of potential microbial activities using soil from an aged diesel fuel spill at Casey Station, East Antarctica. To determine in situ toxicity, gross mineralization and nitrification rates were determined by the stable isotope dilution technique. Petroleum hydrocarbon-contaminated soil (0-8,000 mg kg(-1)), packed at bulk densities of 1.4, 1.7, and 2.0 g cm(-3) to manipulate liquid water content, was incubated at -5°C for one, two, and three months. Although θ(liquid) did not have a significant effect on gross mineralization or nitrification, gross nitrification was sensitive to PHC contamination, with toxicity decreasing over time. In contrast, gross mineralization was not sensitive to PHC contamination. Toxic response of gross nitrification was comparable to potential nitrification activity (PNA) with similar EC25 (effective concentration causing a 25% effect in the test population) values determined by both measurement endpoints (400 mg kg(-1) for gross nitrification compared to 200 mg kg(-1) for PNA), indicating that potential microbial activity assays are good surrogates for in situ toxicity of PHC contamination in polar regions. Copyright © 2011 SETAC.
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Wang, Feng-He; Zhang, Fan; Chen, Ya-Jun; Gao, Jay; Zhao, Bin
2015-12-30
Investigated in this paper were the content, specification distribution, and risk assessment code (RAC) determination of six targeted heavy metals and potentially toxic metals in fly ashes from a municipal solid waste incinerator in China. Contained in it is a comparison of the solidification/stabilization performance of two novel solidifying agents of sixthio guanidine acid (SGA) and tetrathio bicarbamic acid (TBA) with sodium dimethyldithiocarbamate (SDD) and Na2S, and analysis of their leachability in accordance with TCLP 1311 of the US EPA and the extraction procedures of China (HJ/T 299-2007 and HJ/T300-2007). The total concentration of Zn, Cu, Ni, Pb, Cr, Cd is 37383.47, 3080.77, 1583.92, 1356.43, 566.15, and 77.83 mg/kg, respectively. Cr (3.7%) and Pb (7.50%) pose low risk; and Ni (12.93%) and Zn (15.45%) have a medium risk; while Cu (69.84%) and Cd (82.5%) have a very high risk according to their RAC score. Compared with SDD and Na2S, SGA and TBA show an excellent overall solidifying performance due to their multiply hydrosulfide groups that bind with heavy metals very efficiently. The obtained results indicate that the leaching content of Cd, Ni, Pb and Zn is higher than the thresholds prescribed in GB5085.3-2007, and the excessive acetic acid makes its binding capacity stronger in HJ/T 300-2007 than in TCLP 1311. Copyright © 2015 Elsevier B.V. All rights reserved.
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Su, Lianghu; Guo, Guangzhai; Shi, Xinlong; Zuo, Minyu; Niu, Dongjie; Zhao, Aihua; Zhao, Youcai
2013-06-01
Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse. Copyright © 2013 Elsevier Ltd. All rights reserved.
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SEDIMENT TOXICITY IDENTIFICATION EVALUATION (TIE) ...
Sediment contamination in the United States has been amply documented and, in order to comply with the 1972 Clean Water Act, the U.S. Environmental Protection Agency must address the issue of toxic sediments. Contaminated sediments from a number of freshwater and marine sites have demonstrated acute and/or chronic toxicity to a variety of test species, as well as adverse ecological effects such as population declines and changes in community structure. However, simply knowing that a sediment is toxic has limited use. This document provides guidance on the performance of sediment Toxicity Identification and Evaluation (TIE). TIE methods allow for the identification of toxic chemicals or chemical classes causing observed toxicity. The identification of pollutants responsible for toxicity of contaminated sediments has broad application in a number of EPA programs as the methods can be used within the total maximum daily load (TMDL) framework, to link sediment toxicity to specific dischargers, to design cost-effective remediation programs, and to identify environmentally protective options for dredged material disposal. In addition, the identification of specific problem contaminants in sediments could prove to be very useful to EPA programs involved in the development of water or sediment quality guidelines, and the registration of new products such as pesticides. Finally, knowledge of the causes of toxicity that influence ecological changes such as community struc
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Toxicity assessment of individual ingredients of synthetic-based drilling muds (SBMs).
Bakhtyar, Sajida; Gagnon, Marthe Monique
2012-09-01
Synthetic-based drilling muds (SBMs) offer excellent technical characteristics while providing improved environmental performance over other drilling muds. The low acute toxicity and high biodegradability of SBMs suggest their discharge at sea would cause minimal impacts on marine ecosystems, however, chronic toxicity testing has demonstrated adverse effects of SBMs on fish health. Sparse environmental monitoring data indicate effects of SBMs on bottom invertebrates. However, no environmental toxicity assessment has been performed on fish attracted to the cutting piles. SBM formulations are mostly composed of synthetic base oils, weighting agents, and drilling additives such as emulsifiers, fluid loss agents, wetting agents, and brine. The present study aimed to evaluate the impact of exposure to individual ingredients of SBMs on fish health. To do so, a suite of biomarkers [ethoxyresorufin-O-deethylase (EROD) activity, biliary metabolites, sorbitol dehydrogenase (SDH) activity, DNA damage, and heat shock protein] have been measured in pink snapper (Pagrus auratus) exposed for 21 days to individual ingredients of SBMs. The primary emulsifier (Emul S50) followed by the fluid loss agent (LSL 50) caused the strongest biochemical responses in fish. The synthetic base oil (Rheosyn) caused the least response in juvenile fish. The results suggest that the impact of Syndrill 80:20 on fish health might be reduced by replacement of the primary emulsifier Emul S50 with an alternative ingredient of less toxicity to aquatic biota. The research provides a basis for improving the environmental performance of SBMs by reducing the environmental risk of their discharge and providing environmental managers with information regarding the potential toxicity of individual ingredients.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Burgess, R.M.; Cantwell, M.G.; Pelletier, M.C.
2000-04-01
A multiagency effort is underway to develop whole sediment toxicity identification evaluation (TIE) methods. Whole sediment TIE methods will be critical tools for characterizing toxicity at hazardous waste sites and in the conduct of environmental risk assessments. The research approach is based on the predominance of three classes of toxicants in sediments: ammonia, nonpolar organic chemicals, and metals. Here the authors describe a procedure for characterizing acute toxicity caused by metals in whole marine sediments. The procedure involves adding a chelating resin to sediments, resulting in the sequestration of bioavailable metal while not stressing testing organisms. Within the testing chambers,more » the presence of resin resulted in statistically significant reductions in the overlying and interstitial water concentrations of five metals (cadmium, copper, nickel, lead, and zinc) generally by factors of 40 and 200. Toxicity to both the amphipod Ampelisca abdita and mysid Americamysis bahia (formerly Mysidopsis bahia) of sediments spiked with the five metals was decreased by approximately a factor of four when resin was present. While very effective at reducing the concentrations and toxicity of metals, the resin has only minor ameliorative effects on the toxicity of ammonia and a representative nonpolar toxicant (Endosulfan). Resin and accumulated metal were easily isolated from the testing system following exposures allowing for the initiation of phase II TIE (identification) procedures. This procedure using the addition of a chelating resin provides an approach for determining the importance of metals to the toxicity of marine sediments. Work is continuing to validate the method with environmentally contaminated sediments.« less
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Liu, Jingjing; Zha, Fusheng; Deng, Yongfeng; Cui, Kerui; Zhang, Xueqin
2017-12-01
Although the stabilization/solidification method has been widely used for remediation of heavy metal-contaminated soils in recent decades, the engineering behavior and mobility of heavy metal ions under alkaline groundwater conditions are still unclear. Therefore, the unconfined compressive strength test (UCS) combined with toxicity characteristic leaching procedure (TCLP) and general acid neutralization capacity (GANC) was used to investigate the effects of alkalinity (using NaOH to simulate alkalinity in the environment) on the mechanical and leaching characteristics of cement-solidified/stabilized (S/S) Zn-contaminated soils. Moreover, the microstructure was analyzed using the scanning electron microscope (SEM) technology. The results indicated that alkaline environment could accelerate the UCS development compared with specimens without soaking in NaOH solution,, regardless of whether the specimens contained Zn 2+ or not. And the UCS varied obviously attributed to the variations of both NaOH concentration and soaking time. Except for the specimens soaked for 90 days, the leached Zn 2+ concentrations were higher than that of without soaking. However, the leachability of Zn 2+ in all the stabilized specimens is in the regulatory level. ANC results indicated that the Zn 2+ leaching behavior can be divided into three stages related to the initial leachate pH. Moreover, SEM results proved that the alkaline environment could actually facilitate the cement hydration process. The results proved in the present paper could be useful in treating the heavy metal-contaminated soils involved in the solidification/stabilization technology under alkaline environment.
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Effect of Pachybasin on General Toxicity and Developmental Toxicity in Vivo.
Lin, Yi-Ruu; Peng, Kou-Cheng; Chan, Ming-Huan; Peng, Huan-Lin; Liu, Shu-Ying
2017-12-06
To document the safety of pachybasin, a secondary metabolite of Trichoderma harzianum, for use as a bioagricultural agent, it was subjected to general toxicological testing in mice and developmental toxicity in zebrafish. With either 5 or 20 mg kg -1 pachybasin i.p. injection, mice behavioral responses such as motor coordination, spontaneous locomotor activity, or nociceptive pain were not influenced. In long-term effect (daily injection for 14 days), the physiological, hematological, liver, and kidney functions were not altered either. Evidence for the developmental toxicity of pachybasin (10-100 μM) in 72-h exposure period was shown in zebrafish larvae, based on developmental retardation, impairment of chorion, and increase of mortality. In summary, there are no significant general toxicities presented in the pachybasin-treated adult male mice. However, the embryo-toxicity in aquatic biota should be taken into consideration during bioagricultural agent application.
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Subacute toxicity of the mycotoxin cyclopiazonic acid.
van Rensburg, S J
1984-12-01
Cyclopiazonic acid (CA) is known to contaminate processed foods, maize and peanuts. Since previously available toxicity data were limited to the effects of single doses, Wistar-derived rats were given weekly doses of 0, 12 or 21 mg CA/kg body weight in 1 N-sodium bicarbonate, using a dosage volume of 2.5 ml/kg body weight, and subgroups of eight were killed 1 wk after doses 2, 5, 9 and 14. Males on the highest dose level showed mild growth retardation initially and 25% died suddenly during wk 4. No abnormal signs were observed in the surviving males or in any of the females throughout the 15 wk of the experiment. CA induced mild cellular degenerative changes in the myocardium and in several other organs where ballooning of nuclei, especially in ductal epithelia, was also characteristic. The changes were only weakly related to dose level, sex and the number of doses given. The findings suggest that CA is probably a metabolic inhibitor requiring considerable concentrations to exert toxicity. The limited data currently available do not elicit concern in terms of human risk or warrant any particular control procedures.
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Toxicity reduction of photo processing wastewaters
Wang, W.
1992-01-01
The photo processing industry can be characterized by treatment processes and subsequent silver recovery. The effluents generated all contain various amounts of silver. The objectives of this study were to determine toxicity of photo processing effluents and to explore their toxicity mitigation. Six samples, from small shops to a major photo processing center, were studied. Two samples (I and VI) were found to be extremely toxic, causing 100 and 99% inhibition of duckweed frond reproduction, respectively, and were used for subsequent toxicity reduction experiments. Lime and sodium sulfide were effective for the toxicity reduction of Sample VI; both reduced its toxicity to negligible. Sample I was far more toxic and was first diluted to 2.2% and then treated with 0.5 g lime/100 mL, reducing toxicity from 100% to 12% inhibition.
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Distinct C9orf72-Associated Dipeptide Repeat Structures Correlate with Neuronal Toxicity
Krans, Amy; Sawaya, Michael R.; Paulson, Henry L.; Todd, Peter K.; Barmada, Sami J.; Ivanova, Magdalena I.
2016-01-01
Hexanucleotide repeat expansions in C9orf72 are the most common inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The expansions elicit toxicity in part through repeat-associated non-AUG (RAN) translation of the intronic (GGGGCC)n sequence into dipeptide repeat-containing proteins (DPRs). Little is known, however, about the structural characteristics and aggregation propensities of the dipeptide units comprising DPRs. To address this question, we synthesized dipeptide units corresponding to the three sense-strand RAN translation products, analyzed their structures by circular dichroism, electron microscopy and dye binding assays, and assessed their relative toxicity when applied to primary cortical neurons. Short, glycine-arginine (GR)3 dipeptides formed spherical aggregates and selectively reduced neuronal survival compared to glycine-alanine (GA)3 and glycine-proline (GP)3 dipeptides. Doubling peptide length had little effect on the structure of GR or GP peptides, but (GA)6 peptides formed β-sheet rich aggregates that bound thioflavin T and Congo red yet lacked the typical fibrillar morphology of amyloids. Aging of (GA)6 dipeptides increased their β-sheet content and enhanced their toxicity when applied to neurons. We also observed that the relative toxicity of each tested dipeptide was proportional to peptide internalization. Our results demonstrate that different C9orf72-related dipeptides exhibit distinct structural properties that correlate with their relative toxicity. PMID:27776165
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Nowell, Lisa H.; Norman, Julia E.; Moran, Patrick W.; Martin, Jeffrey D.; Stone, Wesley W.
2014-01-01
Pesticide mixtures are common in streams with agricultural or urban influence in the watershed. The Pesticide Toxicity Index (PTI) is a screening tool to assess potential aquatic toxicity of complex pesticide mixtures by combining measures of pesticide exposure and acute toxicity in an additive toxic-unit model. The PTI is determined separately for fish, cladocerans, and benthic invertebrates. This study expands the number of pesticides and degradates included in previous editions of the PTI from 124 to 492 pesticides and degradates, and includes two types of PTI for use in different applications, depending on study objectives. The Median-PTI was calculated from median toxicity values for individual pesticides, so is robust to outliers and is appropriate for comparing relative potential toxicity among samples, sites, or pesticides. The Sensitive-PTI uses the 5th percentile of available toxicity values, so is a more sensitive screening-level indicator of potential toxicity. PTI predictions of toxicity in environmental samples were tested using data aggregated from published field studies that measured pesticide concentrations and toxicity to Ceriodaphnia dubia in ambient stream water. C. dubia survival was reduced to ≤ 50% of controls in 44% of samples with Median-PTI values of 0.1–1, and to 0% in 96% of samples with Median-PTI values > 1. The PTI is a relative, but quantitative, indicator of potential toxicity that can be used to evaluate relationships between pesticide exposure and biological condition.
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Leaching and geochemical behavior of fired bricks containing coal wastes.
Taha, Yassine; Benzaazoua, Mostafa; Edahbi, Mohamed; Mansori, Mohammed; Hakkou, Rachid
2018-03-01
High amounts of mine wastes are continuously produced by the mining industry all over the world. Recycling possibility of some wastes in fired brick making has been investigated and showed promising results. However, little attention is given to the leaching behavior of mine wastes based fired bricks. The objective of this paper is to evaluate the geochemical behavior of fired bricks containing different types of coal wastes. The leachates were analyzed for their concentration of As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Zn and sulfates using different leaching tests; namely Tank Leaching tests (NEN 7375), Toxicity Characteristic Leaching Procedure (TCLP) and pH dependence test (EPA, 1313). The results showed that the release of constituents of potential interest was highly reduced after thermal treatment and were immobilized within the glassy matrix of the fired bricks. Moreover, it was also highlighted that the final pH of all fired samples changed and stabilized around 8-8.5 when the initial pH of leaching solution was in the range 2.5-11.5. The release of heavy metals and metalloids (As) tended to decrease with the increase of pH from acidic to alkaline solutions while Mo displayed a different trend. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Mineral assemblage transformation of a metakaolin-based waste form after geopolymer encapsulation
NASA Astrophysics Data System (ADS)
Williams, Benjamin D.; Neeway, James J.; Snyder, Michelle M. V.; Bowden, Mark E.; Amonette, James E.; Arey, Bruce W.; Pierce, Eric M.; Brown, Christopher F.; Qafoku, Nikolla P.
2016-05-01
Mitigation of hazardous and radioactive waste can be improved through conversion of existing waste to a more chemically stable and physically robust waste form. One option for waste conversion is the fluidized bed steam reforming (FBSR) process. The resulting FBSR granular material was encapsulated in a geopolymer matrix referred to here as Geo-7. This provides mechanical strength for ease in transport and disposal. However, it is necessary to understand the phase assemblage evolution as a result of geopolymer encapsulation. In this study, we examine the mineral assemblages formed during the synthesis of the multiphase ceramic waste form. The FBSR granular samples were created from waste simulant that was chemically adjusted to resemble Hanford tank waste. Another set of samples was created using Savannah River Site Tank 50 waste simulant in order to mimic a blend of waste collected from 68 Hanford tank. Waste form performance tests were conducted using the product consistency test (PCT), the Toxicity Characteristic Leaching Procedure (TCLP), and the single-pass flow-through (SPFT) test. X-ray diffraction analyses revealed the structure of a previously unreported NAS phase and indicate that monolith creation may lead to a reduction in crystallinity as compared to the primary FBSR granular product.
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A nanoremediation strategy for the recovery of an As-polluted soil.
Gil-Díaz, M; Diez-Pascual, S; González, A; Alonso, J; Rodríguez-Valdés, E; Gallego, J R; Lobo, M C
2016-04-01
The present study investigates the impact of the nanoremediation treatment on soil recovery as evaluated by the development of barley plants. Highly As-polluted brownfield soil was treated with nanoscale zero-valent iron (nZVI) commercial suspension at two doses (1% and 10%). Barley plants were cultivated in treated and untreated soils in a growth chamber, and the As, Fe, and nutrients uptake were determined. The efficacy of As immobilization was evaluated according to the toxicity characteristics leaching procedure (TCLP) as well as using a sequential extraction procedure. The application of nZVI reduced the amount of As in the more available fractions and increased the amount of As in the residual fraction. The best immobilization results were obtained for the highest dose of nZVI (10%). In turn, the lower availability of As in nZVI-treated soils, particularly at the dose of 10%, stimulated the development of the barley plants and decreased the As uptake. Neither an important increase of available Fe nor negative impact on soil physico-chemical and biological properties were observed. Thus, our results show that the use of nZVI could be an adequate strategy to recover the land use in As polluted soils. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Comparison of mine waste assessment methods at the Rattler mine site, Virginia Canyon, Colorado
Hageman, Phil L.; Smith, Kathleen S.; Wildeman, Thomas R.; Ranville, James F.
2005-01-01
In a joint project, the mine waste-piles at the Rattler Mine near Idaho Springs, Colorado, were sampled and analyzed by scientists from the U.S. Geological Survey (USGS) and the Colorado School of Mines (CSM). Separate sample collection, sample leaching, and leachate analyses were performed by both groups and the results were compared. For the study, both groups used the USGS sampling procedure and the USGS Field Leach Test (FLT). The leachates generated from these tests were analyzed for a suite of elements using ICP-AES (CSM) and ICP-MS (USGS). Leachate geochemical fingerprints produced by the two groups for composites collected from the same mine waste showed good agreement. In another set of tests, CSM collected another set of Rattler mine waste composite samples using the USGS sampling procedure. This set of composite samples was leached using the Colorado Division of Minerals and Geology (CDMG) leach test, and a modified Toxicity Characteristic Leaching Procedure (TCLP) leach test. Leachate geochemical fingerprints produced using these tests showed a variation of more than a factor of two from the geochemical fingerprints produced using the USGS FLT leach test. We have concluded that the variation in the results is due to the different parameters of the leaching tests and not due to the sampling or analytical methods.
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Mineral assemblage transformation of a metakaolin-based waste form after geopolymer encapsulation
Williams, Benjamin D.; Neeway, James J.; Snyder, Michelle M. V.; ...
2015-12-23
We can improve mitigation of hazardous and radioactive waste through conversion of existing waste to a more chemically stable and physically robust waste form. One option for waste conversion is the fluidized bed steam reforming (FBSR) process. The resulting FBSR granular material was encapsulated in a geopolymer matrix referred to here as Geo-7. This provides mechanical strength for ease in transport and disposal. But, it is necessary to understand the phase assemblage evolution as a result of geopolymer encapsulation. In this study, we examine the mineral assemblages formed during the synthesis of the multiphase ceramic waste form. The FBSR granularmore » samples were created from waste simulant that was chemically adjusted to resemble Hanford tank waste. Another set of samples was created using Savannah River Site Tank 50 waste simulant in order to mimic a blend of waste collected from 68 Hanford tank. Waste form performance tests were conducted using the product consistency test (PCT), the Toxicity Characteristic Leaching Procedure (TCLP), and the single-pass flow-through (SPFT) test. Finally, X-ray diffraction analyses revealed the structure of a previously unreported NAS phase and indicate that monolith creation may lead to a reduction in crystallinity as compared to the primary FBSR granular product.« less
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Klüver, Nils; König, Maria; Ortmann, Julia; Massei, Riccardo; Paschke, Albrecht; Kühne, Ralph; Scholz, Stefan
2015-06-02
The fish embryo toxicity test has been proposed as an alternative for the acute fish toxicity test, but concerns have been raised for its predictivity given that a few compounds have been shown to exhibit a weak acute toxicity in the fish embryo. In order to better define the applicability domain and improve the predictive capacity of the fish embryo test, we performed a systematic analysis of existing fish embryo and acute fish toxicity data. A correlation analysis of a total of 153 compounds identified 28 compounds with a weaker or no toxicity in the fish embryo test. Eleven of these compounds exhibited a neurotoxic mode of action. We selected a subset of eight compounds with weaker or no embryo toxicity (cyanazine, picloram, aldicarb, azinphos-methyl, dieldrin, diquat dibromide, endosulfan, and esfenvalerate) to study toxicokinetics and a neurotoxic mode of action as potential reasons for the deviating fish embryo toxicity. Published fish embryo LC50 values were confirmed by experimental analysis of zebrafish embryo LC50 according to OECD guideline 236. Except for diquat dibromide, internal concentration analysis did not indicate a potential relation of the low sensitivity of fish embryos to a limited uptake of the compounds. Analysis of locomotor activity of diquat dibromide and the neurotoxic compounds in 98 hpf embryos (exposed for 96 h) indicated a specific effect on behavior (embryonic movement) for the neurotoxic compounds. The EC50s of behavior for neurotoxic compounds were close to the acute fish toxicity LC50. Our data provided the first evidence that the applicability domain of the fish embryo test (LC50s determination) may exclude neurotoxic compounds. However, neurotoxic compounds could be identified by changes in embryonic locomotion. Although a quantitative prediction of acute fish toxicity LC50 using behavioral assays in fish embryos may not yet be possible, the identification of neurotoxicity could trigger the conduction of a conventional fish
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Shim, Taeyong; Yoo, Jisu; Ryu, Changkook; Park, Yong-Kwon; Jung, Jinho
2015-12-01
This study aims to evaluate the physiochemical properties, sorption characteristics, and toxicity effects of biochar (BC) produced from Miscanthus sacchariflorus via slow pyrolysis at 500°C and its steam activation product (ABC). Although BC has a much lower surface area than ABC (181 and 322m(2)g(-1), respectively), the Cu sorption capacities of BC and ABC are not significantly different (p>0.05). A two-compartment model successfully explains the sorption of BC and ABC as being dominated by fast and slow sorption processes, respectively. In addition, both BC and ABC efficiently eliminate the toxicity of Cu towards Daphnia magna. However, ABC itself induced acute toxicity to D. magna, which is possibly due to increased aromaticity upon steam activation. These findings suggest that activation of BC produced from M. sacchariflorus at a pyrolytic temperature of 500°C may not be appropriate in terms of Cu sorption and toxicity reduction. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Building a developmental toxicity ontology.
Baker, Nancy; Boobis, Alan; Burgoon, Lyle; Carney, Edward; Currie, Richard; Fritsche, Ellen; Knudsen, Thomas; Laffont, Madeleine; Piersma, Aldert H; Poole, Alan; Schneider, Steffen; Daston, George
2018-04-03
As more information is generated about modes of action for developmental toxicity and more data are generated using high-throughput and high-content technologies, it is becoming necessary to organize that information. This report discussed the need for a systematic representation of knowledge about developmental toxicity (i.e., an ontology) and proposes a method to build one based on knowledge of developmental biology and mode of action/ adverse outcome pathways in developmental toxicity. This report is the result of a consensus working group developing a plan to create an ontology for developmental toxicity that spans multiple levels of biological organization. This report provide a description of some of the challenges in building a developmental toxicity ontology and outlines a proposed methodology to meet those challenges. As the ontology is built on currently available web-based resources, a review of these resources is provided. Case studies on one of the most well-understood morphogens and developmental toxicants, retinoic acid, are presented as examples of how such an ontology might be developed. This report outlines an approach to construct a developmental toxicity ontology. Such an ontology will facilitate computer-based prediction of substances likely to induce human developmental toxicity. © 2018 Wiley Periodicals, Inc.
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Toxicity Estimation Software Tool (TEST)
The Toxicity Estimation Software Tool (TEST) was developed to allow users to easily estimate the toxicity of chemicals using Quantitative Structure Activity Relationships (QSARs) methodologies. QSARs are mathematical models used to predict measures of toxicity from the physical c...
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[Streptococcal toxic shock syndrome].
Gvozdenović, Ljiljana; Pasternak, Janko; Milovanović, Stanislav; Ivanov, Dejan; Milić, Sasa
2010-01-01
Streptococcal toxic shock syndrome is now recognized as a toxin-mediated, multisystem illness. It is characterized by an early onset of shock with multiorgan failure and continues to be associated with high morbidity and mortality, caused by group A Streptococcus pyogenes. The symptoms for staphylococcal and streptococcal toxic shock syndrome are similar. Streptococcal toxic shock syndrome was not well described until 1993, when children who had suffered from varicella presented roughly 2-4 weeks later with a clinical syndrome highly suggestive of toxic shock syndrome. It is characterized by a sudden onset of fever, chills, vomiting, diarrhea, muscle aches and rash. It can rapidly progress to severe and intractable hypotension and multisystem dysfunction. Almost every organ system can he involved. Complications of streptococcal toxic shock syndrome may include kidney failure, liver failure (and even death. Crystalloids and inotropic agents are used to treat the hypovolemic shock aggressively, with close monitoring of the patient's mean arterial pressure and central venous pressure. An immediate and aggressive management of hypovolemic shock is essential in streptococcal toxic shock syndrome. Targeted antibiotics are indicated: penicillin or a beta-lactam antibiotic is used for treating group A streptococci, and clindamycin has emerged as a key portion of the standard treatment.
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Exploring the Impact of Toxic Attitudes and a Toxic Environment on the Veterinary Healthcare Team.
Moore, Irene C; Coe, Jason B; Adams, Cindy L; Conlon, Peter D; Sargeant, Jan M
2015-01-01
The objective of this qualitative study was to compare veterinarians' and Registered Veterinary Technicians' (RVT's) perceptions of the veterinary healthcare team with respect to the impact of toxic attitudes and a toxic environment. Focus group interviews using a semi-structured interview guide and follow up probes were held with four veterinarian groups (23 companion animal veterinarians) and four Registered Veterinary Technician groups (26 RVTs). Thematic analysis of the discussions indicated both veterinarian and RVT participants felt team members with manifestations of toxic attitudes negatively impacted veterinary team function. These manifestations included people being disrespectful, being resistant to change, always wanting to be the "go to person," avoiding conflict, and lacking motivation. When conflict was ignored, or when people with toxic attitudes were not addressed, a toxic environment often resulted. A toxic environment sometimes manifested when "broken communication and tension between staff members" occurred as a result of employees lacking confidence, skills, or knowledge not being managed properly. It also occurred when employees did not feel appreciated, when there was difficulty coping with turnover, and when there were conflicting demands. The presence of people manifesting a toxic attitude was a source of frustration for both veterinarian and RVT participants. Prompt and consistent attention to negative behaviors is recommended to reduce the development of a toxic environment.
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Naidoo, V; du Preez, M; Rakgotho, T; Odhav, B; Buckley, C A
2002-01-01
Industrial effluents and leachates from hazardous landfill sites were tested for toxicity using the anaerobic toxicity assay. This test was done on several industrial effluents (brewery spent grain effluent, a chemical industry effluent, size effluent), and several hazardous landfill leachates giving vastly different toxicity results. The brewery effluent, spent grain effluent and size effluent were found to be less toxic than the chemical effluent and hazardous landfill leachate samples. The chemical industry effluent was found to be most toxic. Leachate samples from the H:h classified hazardous landfill site were found to be less toxic at high concentrations (40% (v/v)) while the H:H hazardous landfill leachate samples were found to be more toxic even at low concentrations of 4% (v/v). The 30 d biochemical methane potential tests revealed that the brewery effluent, organic spent grain effluent and size effluent were 89%, 63%, and 68% biodegradable, respectively. The leachate from Holfontein hazardous landfill site was least biodegradable (19%) while the chemical effluent and Aloes leachate were 29% and 32% biodegradable under anaerobic conditions.
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Feng, Xiangyu; Ge, Yunshan; Ma, Chaochen; Tan, Jianwei
2015-01-01
To evaluate the effects of particulate oxidation catalyst (POC) on unregulated pollutant emission and toxicity characteristics, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), soot, soluble organic fractions (SOF) and sulphate emissions emitted from a heavy-duty diesel engine retrofitted with a POC were investigated on a diesel bench. The particulate matter (PM) in the exhaust was collected by Teflon membrane, and the PAHs and VOCs were analysed by a gas chromatography/mass spectrometer (GC/MS). The results indicate that the POC exhibits good performance on the emission control of VOCs, PAHs and PM. The POC and the diesel particulate filters (DPF) both show a good performance on reducing the VOCs emission. Though the brake-specific emission (BSE) reductions of the total PAHs by the POC were lower than those by the DPF, the POC still removed almost more than 50% of the total PAHs emission. After the engine was retrofitted with the POC, the reductions of the PM mass, SOF and soot emissions were 45.2-89.0%, 7.8-97.7% and 41.7-93.3%, respectively. The sulphate emissions decreased at low and medium loads, whereas at high load, the results were contrary. The PAHs emissions were decreased by 32.4-69.1%, and the contributions of the PAH compounds were affected by the POC, as well as by load level. The benzo[a]pyrene equivalent (BaPeq) of PAHs emissions were reduced by 35.9-97.6% with the POC. The VOCs emissions were reduced by 21.8-94.1% with the POC, and the reduction was more evident under high load.
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TOXICITY SCREENING WITH ZEBRAFISH ASSAY
The proposed toxicity screening will help EPA to prioritize chemicals for further testing, and it may also alert chemical manufacturers that some of their commercial products may be toxic. The proposed toxicity pathway studies will improve the research community’s abi...
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TOXICITY TESTS FOR SEDIMENT QUALITY ASSESSMENTS
Toxic sediments have contributed to a wide-variety of environmental problems around the world. The observed effects include direct toxic effects to aquatic life, bio-magnification of toxicants in the food chain, and economic impacts. This chapter discusses the use of toxicity...
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1980-11-01
59 programmable calculator . Method 1 will most likely be used if there is a toxic corridor length table for the chemical; Method 2 if there is no table...experience of the forecaster in making this forecast, availability of a toxic corridor length table for the released chemical, and availability of a TI
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Toxicity study of Vernonia cinerea.
Latha, L Yoga; Darah, I; Jain, K; Sasidharan, S
2010-01-01
The methanol extract of Vernonia cinerea Less (Asteraceae), which exhibited antimicrobial activity, was tested for toxicity. In an acute toxicity study using mice, the median lethal dose (LD(50)) of the extract was greater than 2000 mg/kg, and we found no pathological changes in macroscopic examination by necropsy of mice treated with extract. As well as the oral acute toxicity study, the brine shrimp lethality test was also done. Brine shrimp test LC(50) values were 3.87 mg/mL (6 h) and 2.72 mg/mL (24 h), exhibiting no significant toxicity result. In conclusion, the methanol extract of V. cinerea did not produce toxic effects in mice and brine shrimp.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Douglas, W.S.; Hayes, K.R.
1994-12-31
The IQ TOXICITY TEST{trademark} is a toxicity screening test that evaluates the organism`s galactosidase enzyme system functionality as a predictor of acute toxicity. Organisms are exposed to a potentially toxic solution for approximately one hour. Following the exposure, the organisms are exposed to a slurry of a galactoside sugar tagged with a fluorescent marker (methylumbelliferyl galactoside) for 15--20 minutes. A black light can then be used to examine whether the hemolymph of the organism contains free umbelliferone, which brightly fluoresces. The organisms are then scored as ``on`` or ``off`` with respect to free umbelliferone. This endpoint can then be usedmore » to calculate an EC50, which is comparable to a whole effluent, pure compound, or sediment toxicity test. Slightly different methodologies are used for different toxicity test organisms. The objective of this presentation is to discuss the use of the IQ{trademark} methodology with porewater extract exposures of the amphipod Hyalella azteca as a predictor of results of whole sediment toxicity tests. The results of over thirty 10 and 28-day whole sediment toxicity tests and the concurrent Hyalella azteca 10 TOXICITY TESTS{trademark} are compared and discussed. The use of screening tests as a reduced cost method for initial site assessment will be discussed.« less
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Kameda, Hiroshi; Usugi, Sayaka; Kobayashi, Mana; Fukui, Naoya; Lee, Seki; Hongo, Kunihiro; Mizobata, Tomohiro; Sekiguchi, Yuki; Masaki, Yu; Kobayashi, Amane; Oroguchi, Tomotaka; Nakasako, Masayoshi; Takayama, Yuki; Yamamoto, Masaki; Kawata, Yasushi
2017-01-01
The aggregation and deposition of α-synuclein (αSyn) in neuronal cells is correlated to pathogenesis of Parkinson's disease. Although the mechanism of αSyn aggregation and fibril formation has been studied extensively, the structural hallmarks that are directly responsible for toxicity toward cells are still under debate. Here, we have compared the structural characteristics of the toxic intermediate molecular species of αSyn and similar toxic species of another protein, GroES, using coherent X-ray diffraction analysis. Using coherent X-ray free electron laser pulses of SACLA, we analysed αSyn and GroES fibril intermediate species and characterized various aggregate structures. Unlike previous studies where an annular oligomeric form of αSyn was identified, particle reconstruction from scattering traces suggested that the specific forms of the toxic particles were varied, with the sizes of the particles falling within a specific range. We did however discover a common structural feature in both αSyn and GroES samples; the edges of the detected particles were nearly parallel and produced a characteristic diffraction pattern in the diffraction experiments. The presence of parallel-edged particles in toxic intermediates of αSyn and GroES fibrillogenesis pointed towards a plausible common molecular interface that leads to the formation of mature fibrils. © The Authors 2016. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.
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Elkus, A.; LeBlanc, L.; Kim, C.; Van Beneden, R.; Mayer, G.
2006-01-01
With funding from the George Mitchell Center for the Environment at the University of Maine, a team of scientists used a simple laboratory-based sediment resuspension design, and two well-established aquatic toxicology models, fathead minnows (Pimephales promelas) and zebrafish (Danio rerio), to evaluate if resuspension of Penobscot river sediment significantly elevates the toxicity of river water and to provide preliminary information on the types of chemicals likely to desorb during resuspension. The group collected sediments from two sites with known chemical contamination downstream of the Great Works and Veazie dams. The sediments were examined to determine the dynamics of PAH desorption and degradation under different resuspension frequencies. The scientists used clarified water from resuspension experiments for toxicity tests with the water-flea Ceriodaphnia dubia, and other aquatic test organisms to infer toxicity from sediments from northern California rivers. Data from the study will help ascertain whether metals and/or xenoestrogens are present in the desorption water and give insight into possible avenues of sediment remediation.
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Hudson, R.H.; Haegele, M.A.; Tucker, R.K.
1979-01-01
Acute oral (po) and 24-hr percutaneous (perc) LD50 values for 21 common pesticides (19 anticholinesterases, of which 18 were organophosphates, and one was a carbamate; one was an organochlorine central nervous system stimulant; and one was an organonitrogen pneumotoxicant) were determined in mallards (Anas platyrhynchos). Three of the pesticides tested were more toxic percutaneously than orally. An index to the percutaneous hazard of a pesticide, the dermal toxicity index (DTI = po LD50/perc LD50 ? 100), was also calculated for each pesticide. These toxicity values in mallards were compared with toxicity data for rats from the literature. Significant positive correlations were found between log po and log percutaneous LD50 values in mallards (r = 0.65, p 0.10). Variations in percutaneous methodologies are discussed with reference to interspecies variation in toxicity values. It is recommended that a mammalian DTI value approaching 30 be used as a guideline for the initiation of percutaneous toxicity studies in birds, when the po LD50 and/or projected percutaneous LD50 are less than expected field exposure levels.
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Zawierucha, Iwona; Kozlowski, Cezary; Malina, Grzegorz
2016-04-01
Heavy metals from industrial processes are of special concern because they produce chronic poisoning in the aquatic environment. More strict environmental regulations on the discharge of toxic metals require the development of various technologies for their removal from polluted streams (i.e. industrial wastewater, mine waters, landfill leachate, and groundwater). The separation of toxic metal ions using immobilized materials (novel sorbents and membranes with doped ligands), due to their high selectivity and removal efficiency, increased stability, and low energy requirements, is promising for improving the environmental quality. This critical review is aimed at studying immobilized materials as potential remediation agents for the elimination of numerous toxic metal (e.g. Pb, Cd, Hg, and As) ions from polluted streams. This study covers the general characteristics of immobilized materials and separation processes, understanding of the metal ion removal mechanisms, a review of the application of immobilized materials for the removal of toxic metal ions, as well as the impacts of various parameters on the removal efficiency. In addition, emerging trends and opportunities in the field of remediation technologies using these materials are addressed.
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Brown, Alastair; Thatje, Sven; Hauton, Chris
2017-09-05
Mineral prospecting in the deep sea is increasing, promoting concern regarding potential ecotoxicological impacts on deep-sea fauna. Technological difficulties in assessing toxicity in deep-sea species has promoted interest in developing shallow-water ecotoxicological proxy species. However, it is unclear how the low temperature and high hydrostatic pressure prevalent in the deep sea affect toxicity, and whether adaptation to deep-sea environmental conditions moderates any effects of these factors. To address these uncertainties we assessed the effects of temperature and hydrostatic pressure on lethal and sublethal (respiration rate, antioxidant enzyme activity) toxicity in acute (96 h) copper and cadmium exposures, using the shallow-water ecophysiological model organism Palaemon varians. Low temperature reduced toxicity in both metals, but reduced cadmium toxicity significantly more. In contrast, elevated hydrostatic pressure increased copper toxicity, but did not affect cadmium toxicity. The synergistic interaction between copper and cadmium was not affected by low temperature, but high hydrostatic pressure significantly enhanced the synergism. Differential environmental effects on toxicity suggest different mechanisms of action for copper and cadmium, and highlight that mechanistic understanding of toxicity is fundamental to predicting environmental effects on toxicity. Although results infer that sensitivity to toxicants differs across biogeographic ranges, shallow-water species may be suitable ecotoxicological proxies for deep-sea species, dependent on adaptation to habitats with similar environmental variability.
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Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.
1998-01-01
Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. We investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by ???70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.
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Brix, Kevin V; Gerdes, Robert; Grosell, Martin
2010-10-01
A series of Toxicity Identification Evaluations (TIEs) to identify the cause(s) of observed toxicity to Ceriodaphnia dubia have been conducted on a hard rock mining effluent. Characteristic of hard rock mining discharges, the effluent has elevated (∼3000 mg l(-1)) total dissolved solids (TDS) composed primarily of Ca(2+) and SO(4)(2-). The effluent typically exhibits 6-12 toxic units (TUs) when tested with C. dubia. Phase I and II toxicity identification evaluations (TIEs) indicated Ca(2+) and SO(4)(2-) contributed only ∼4 TUs of toxicity, but this was likely an underestimate due to problems with simulating the supersaturated CaSO(4) concentrations in the effluent. Treatment of the effluent with BaCO(3) to precipitate Ca(2+) and SO(4)(2-) revealed that these ions contribute ∼6 TUs of the observed toxicity, but the remaining source(s) of toxicity (up to 6 TUs) remained unidentified. Subsequent investigations identified thiocyanate (SCN(-)) in the effluent at 100-150 μM. Toxicity tests reveal that C. dubia are sensitive to SCN(-) with an estimated IC25 of 8.3 μΜ for reproduction in moderately hard water suggesting between 12 and 18 TUs of toxicity in the effluent. Additional experiments demonstrated that SCN(-) toxicity is reduced in the high TDS matrix of the mining effluent. Testing of a mock effluent simulating the major ion and SCN(-) concentrations resulted in 10.4 TUs, suggesting that Ca(2+), SO(4)(2-) and SCN(-) are the three toxicants present in this effluent. This research suggests SCN(-) may be a more common cause of toxicity in mining effluents than is generally recognized. Copyright © 2010 Elsevier Inc. All rights reserved.
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Dependence of Nanoparticle Toxicity on Their Physical and Chemical Properties
NASA Astrophysics Data System (ADS)
Sukhanova, Alyona; Bozrova, Svetlana; Sokolov, Pavel; Berestovoy, Mikhail; Karaulov, Alexander; Nabiev, Igor
2018-02-01
Studies on the methods of nanoparticle (NP) synthesis, analysis of their characteristics, and exploration of new fields of their applications are at the forefront of modern nanotechnology. The possibility of engineering water-soluble NPs has paved the way to their use in various basic and applied biomedical researches. At present, NPs are used in diagnosis for imaging of numerous molecular markers of genetic and autoimmune diseases, malignant tumors, and many other disorders. NPs are also used for targeted delivery of drugs to tissues and organs, with controllable parameters of drug release and accumulation. In addition, there are examples of the use of NPs as active components, e.g., photosensitizers in photodynamic therapy and in hyperthermic tumor destruction through NP incorporation and heating. However, a high toxicity of NPs for living organisms is a strong limiting factor that hinders their use in vivo. Current studies on toxic effects of NPs aimed at identifying the targets and mechanisms of their harmful effects are carried out in cell culture models; studies on the patterns of NP transport, accumulation, degradation, and elimination, in animal models. This review systematizes and summarizes available data on how the mechanisms of NP toxicity for living systems are related to their physical and chemical properties.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Leon, Lisa R.
2008-11-15
Thermal stress can have a profound impact on the physiological responses that are elicited following environmental toxicant exposure. The efficacy by which toxicants enter the body is directly influenced by thermoregulatory effector responses that are evoked in response to high ambient temperatures. In mammals, the thermoregulatory response to heat stress consists of an increase in skin blood flow and moistening of the skin surface to dissipate core heat to the environment. These physiological responses may exacerbate chemical toxicity due to increased permeability of the skin, which facilitates the cutaneous absorption of many environmental toxicants. The core temperature responses that aremore » elicited in response to high ambient temperatures, toxicant exposure or both can also have a profound impact on the ability of an organism to survive the insult. In small rodents, the thermoregulatory response to thermal stress and many environmental toxicants (such as organophosphate compounds) is often biphasic in nature, consisting initially of a regulated reduction in core temperature (i.e., hypothermia) followed by fever. Hypothermia is an important thermoregulatory survival strategy that is used by small rodents to diminish the effect of severe environmental insults on tissue homeostasis. The protective effect of hypothermia is realized by its effects on chemical toxicity as molecular and cellular processes, such as lipid peroxidation and the formation of reactive oxygen species, are minimized at reduced core temperatures. The beneficial effects of fever are unknown under these conditions. Perspective is provided on the applicability of data obtained in rodent models to the human condition.« less
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Quality characteristics and safety of smoke-flavoured water.
Tano-Debrah, Kwaku; Amamoo-Otchere, Joanne; Karikari, A Y; Diako, Charles
2007-06-01
Smoke-flavoured water is produced in Ghana by filling a previously smoked container with potable water and allowing the water to condition with the smoke to attain a characteristic rain water flavour. Owing to the current knowledge on the toxicity, carcinogenicity and other safety issues of some smoke-constituents, the commercial production of the product is becoming a public health concern. This study sought to determine the effects of the smoke-flavouring process on the quality characteristics of smoke-flavoured water to predict the safety of the product. A traditional and a commercial protocol for the production of smoke-flavoured water were simulated in the laboratory and at the site of a company which used to produce the product, respectively. Samples of the flavoured water produced were analyzed for pH, colour, turbidity, conductivity, total hardness, dissolved oxygen content (DO), biochemical oxygen demand (BOD), the polycyclic aromatic hydrocarbon constituents (PAHs), coliform count, and flavour acceptability. Data obtained were evaluated in reference to data on control samples prepared during the investigations. The results obtained suggested that the smoke-flavouring process may not significantly change most of the physico-chemical and microbiological characteristics of the water processed, and thus not affect the drinking quality characteristics of the water. The process however has the potential of adding some organic compounds, which could include polycyclic aromatic hydrocarbons (PAHs), the group that may have the toxicity and carcinogenic effects. The types of PAHs and their concentrations are expected to vary with the process characteristics, but could be insignificantly low to affect the safety of the water. The results suggest a need for some standardization of the process.
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Cryoprotectant Toxicity: Facts, Issues, and Questions
2015-01-01
Abstract High levels of penetrating cryoprotectants (CPAs) can eliminate ice formation during cryopreservation of cells, tissues, and organs to cryogenic temperatures. But CPAs become increasingly toxic as concentration increases. Many strategies have been attempted to overcome the problem of eliminating ice while minimizing toxicity, such as attempting to optimize cooling and warming rates, or attempting to optimize time of adding individual CPAs during cooling. Because strategies currently used are not adequate, CPA toxicity remains the greatest obstacle to cryopreservation. CPA toxicity stands in the way of cryogenic cryopreservation of human organs, a procedure that has the potential to save many lives. This review attempts to describe what is known about CPA toxicity, theories of CPA toxicity, and strategies to reduce CPA toxicity. Critical analysis and suggestions are also included. PMID:25826677
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TOXICITY IDENTIFICATION EVALUATION OF A WASTEWATER TREATMENT PLANT EFFLUENT WITH IONIC TOXICANTS
A publicly owned treatment works (POTW) effluent had been shown to cause chronic toxicity with the cladoceran, Ceriodaphnia dubia. We conducted A TIE and the weight-of-evidence approach identified chloride as a major contributor to the effluent toxicity. Several characterization...
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Oxaliplatin-Related Ocular Toxicity
Mesquida, Marina; Sanchez-Dalmau, Bernardo; Ortiz-Perez, Santiago; Pelegrín, Laura; Molina-Fernandez, Juan José; Figueras-Roca, Marc; Casaroli-Marano, Ricardo; Adán, Alfredo
2010-01-01
We report the case of a 52-year-old woman with advanced colorectal cancer who was treated with oxaliplatin on a FOLFOX schedule. After 3 cycles of chemotherapy, she started to complain of visual loss, altered color vision and neurological symptoms. Due to the suspicion of ocular and neurological toxicity, antineoplastic treatment was stopped. Her visual field showed a concentric bilateral scotoma and the electrooculogram test revealed severe impairment of the retinal pigment epithelium. Visual acuity, color vision and visual field recovered completely 8 months later, although electrooculogram remained abnormal. Ocular toxicity has been reported as an infrequent adverse event of oxaliplatin. Findings in this case indicate toxicity of this chemotherapeutic agent on the retinal pigment epithelium, which has not been reported before. This damage could be permanent, and it thus differs from previously described oxaliplatin-induced ocular toxicities, which are usually transient and reversible. With increasing use of oxaliplatin as first-line treatment in advanced colorectal cancer, we have to be aware of this possible toxicity. PMID:21151636
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Essential oil from fruit of Xylopia langsdorffiana: antitumour activity and toxicity.
Moura, Ana Paula Gomes; Beltrão, Daiene Martins; Pita, João Carlos Lima Rodrigues; Xavier, Aline Lira; Brito, Monalisa Taveira; Sousa, Tatyanna Kelvia Gomes de; Batista, Leônia Maria; Carvalho, João Ernesto de; Ruiz, Ana Lúcia Tasca Gois; Della Torre, Adriana; Duarte, Marcelo Cavalcante; Tavares, Josean Fechine; da Silva, Marcelo Sobral; Sobral, Marianna Vieira
2016-12-01
The genus Xylopia L. (Annonaceae) includes aromatic plants that have both nutritional and medicinal uses. Essential oils of Xylopia species have antitumour effects. However, the efficacy of the essential oil from the fruit of Xylopia langsdorffiana St. Hil & Tul. (EOX) has not been examined. EOX was evaluated to determine its chemical composition, antitumour activity and toxicity. EOX was obtained from fresh fruits of X. langsdorffiana subjected to hydrodistillation, and gas chromatography-mass spectrometry was used to characterize the chemical composition of EOX. The toxicity of EOX was evaluated using haemolysis, acute toxicity and micronucleus assays. The in vitro antitumour activity of EOX was investigated using the sulforhodamine B assay. The sarcoma 180 murine tumour model was used to evaluate the in vivo antitumour activity and toxicity of EOX (50 and 100 mg/kg) after 7 d of treatment. The major components of EOX were α-pinene (34.57%) and limonene (31.75%). The HC 50 (concentration producing 50% haemolysis) was 293.6 μg/ml. EOX showed greater selectivity for the leukaemia cell line K562, with total growth inhibition (TGI) (concentration producing TGI) of 1.8 μg/ml, and for multidrug-resistant ovarian tumour cell line NCI/ADR-RES (TGI of 45.4 μg/ml). The LD 50 was approximately 351.09 mg/kg. At doses of 50 and 100 mg/kg, EOX inhibited the in vivo growth of sarcoma 180 by 38.67 and 54.32%, respectively. EOX displayed minor hepatic alterations characteristic of acute hepatitis and induced no genotoxicity. EOX showed in vitro and in vivo antitumour activity and low toxicity, which warrants further pharmacological studies.
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Brumbaugh, William G.; Besser, John M.; Ingersoll, Christopher G.; May, Thomas W.; Ivey, Chris D.; Schlekat, Christian E.; Garman, Emily R.
2013-01-01
Two spiking methods were compared and nickel (Ni) partitioning was evaluated during a series of toxicity tests with 8 different freshwater sediments having a range of physicochemical characteristics. A 2-step spiking approach with immediate pH adjustment by addition of NaOH at a 2:1 molar ratio to the spiked Ni was effective in producing consistent pH and other chemical characteristics across a range of Ni spiking levels. When Ni was spiked into sediment having a high acid-volatile sulfide and organic matter content, a total equilibration period of at least 10 wk was needed to stabilize Ni partitioning. However, highest spiking levels evidently exceeded sediment binding capacities; therefore, a 7-d equilibration in toxicity test chambers and 8 volume-additions/d of aerobic overlying water were used to avoid unrealistic Ni partitioning during toxicity testing. The 7-d pretest equilibration allowed excess spiked Ni and other ions from pH adjustment to diffuse from sediment porewater and promoted development of an environmentally relevant, 0.5- to 1-cm oxic/suboxic sediment layer in the test chambers. Among the 8 different spiked sediments, the logarithm of sediment/porewater distribution coefficient values (log Kd) for Ni during the toxicity tests ranged from 3.5 to 4.5. These Kd values closely match the range of values reported for various field Ni-contaminated sediments, indicating that testing conditions with our spiked sediments were environmentally realistic.
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Applicability of ambient toxicity testing to national or regional water-quality assessment
Elder, John F.
1990-01-01
Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Descriptions of existing conditions may be achieved by various kinds of chemical and hydrologic analyses, whereas information about the effects of such conditions on living organisms depends on biological monitoring. Toxicity testing is one type of biological monitoring that can be used to identify possible effects of toxic contaminants. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water-quality assessments. These purposes may include identification of areas that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. Toxicity-test results are most effective when used as a complement to chemical analyses, hydrologic measurements, and other biological monitoring. However, all toxicity-testing procedures have certain limitations that must be considered in developing the methodology and applications of toxicity testing in any large-scale water-quality-assessment program. A wide variety of toxicity-test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the selections made relative to four characteristics: (1) test species, (2) endpoint (acute or chronic), (3) test-enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity-test approaches vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing, whereby the test organism is exposed to naturally occurring substances that contain toxicant mixtures in an organic or inorganic matrix, is more likely to meet these needs than are procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful
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Exploring the Impact of Toxic Attitudes and a Toxic Environment on the Veterinary Healthcare Team
Moore, Irene C.; Coe, Jason B.; Adams, Cindy L.; Conlon, Peter D.; Sargeant, Jan M.
2015-01-01
The objective of this qualitative study was to compare veterinarians’ and Registered Veterinary Technicians’ (RVT’s) perceptions of the veterinary healthcare team with respect to the impact of toxic attitudes and a toxic environment. Focus group interviews using a semi-structured interview guide and follow up probes were held with four veterinarian groups (23 companion animal veterinarians) and four Registered Veterinary Technician groups (26 RVTs). Thematic analysis of the discussions indicated both veterinarian and RVT participants felt team members with manifestations of toxic attitudes negatively impacted veterinary team function. These manifestations included people being disrespectful, being resistant to change, always wanting to be the “go to person,” avoiding conflict, and lacking motivation. When conflict was ignored, or when people with toxic attitudes were not addressed, a toxic environment often resulted. A toxic environment sometimes manifested when “broken communication and tension between staff members” occurred as a result of employees lacking confidence, skills, or knowledge not being managed properly. It also occurred when employees did not feel appreciated, when there was difficulty coping with turnover, and when there were conflicting demands. The presence of people manifesting a toxic attitude was a source of frustration for both veterinarian and RVT participants. Prompt and consistent attention to negative behaviors is recommended to reduce the development of a toxic environment. PMID:26779492
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Wik, Anna; Dave, Göran
2006-09-01
Large amounts of tire rubber are deposited along the roads due to tread wear. Several compounds may leach from the rubber and cause toxicity to aquatic organisms. To investigate the toxic effects of tire wear material from different tires, rubber was abraded from the treads of twenty-five tires. Leachates were prepared by allowing the rubber to equilibrate with dilution water at 44 degrees C for 72 h. Then the rubber was filtered from the leachates, and test organisms (Daphnia magna) were added. Forty-eight hour EC50s ranged from 0.5 to >10.0 g l(-1). The toxicity identification evaluation (TIE) indicated that non-polar organic compounds caused most of the toxicity. UV exposure of the filtered tire leachates caused no significant increase in toxicity. However, when tested as unfiltered leachates (the rubber was not filtered from the leachates before addition of D. magna) photo-enhanced toxicity was considerable for some tires, which means that test procedures are important when testing tire leachates for aquatic (photo) toxicity. The acute toxicity of tire wear for Daphnia magna was found to be <40 times a predicted environmental concentration based on reports on the concentration of a tire component found in environmental samples, which emphasizes the need for a more extensive risk assessment of tire wear for the environment.
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Food plant toxicants and safety Risk assessment and regulation of inherent toxicants in plant foods.
Essers, A J; Alink, G M; Speijers, G J; Alexander, J; Bouwmeister, P J; van den Brandt, P A; Ciere, S; Gry, J; Herrman, J; Kuiper, H A; Mortby, E; Renwick, A G; Shrimpton, D H; Vainio, H; Vittozzi, L; Koeman, J H
1998-05-01
The ADI as a tool for risk management and regulation of food additives and pesticide residues is not readily applicable to inherent food plant toxicants: The margin between actual intake and potentially toxic levels is often small; application of the default uncertainty factors used to derive ADI values, particularly when extrapolating from animal data, would prohibit the utilisation of the food, which may have an overall beneficial health effect. Levels of inherent toxicants are difficult to control; their complete removal is not always wanted, due to their function for the plant or for human health. The health impact of the inherent toxicant is often modified by factors in the food, e.g. the bioavailability from the matrix and interaction with other inherent constituents. Risk-benefit analysis should be made for different consumption scenarios, without the use of uncertainty factors. Crucial in this approach is analysis of the toxicity of the whole foodstuff. The relationship between the whole foodstuff and the pure toxicant is expressed in the `product correction factor' (PCF). Investigations in humans are essential so that biomarkers of exposure and for effect can be used to analyse the difference between animals and humans and between the food and the pure toxicant. A grid of the variables characterising toxicity is proposed, showing their inter-relationships. A flow diagram for risk estimate is provided, using both toxicological and epidemiological studies.
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Wang, Xiao H.; Yu, Yang; Huang, Tao; Qin, Wei C.; Su, Li M.; Zhao, Yuan H.
2016-01-01
Investigations on the relationship of toxicities between species play an important role in the understanding of toxic mechanisms to environmental organisms. In this paper, the toxicity data of 949 chemicals to fish and 1470 chemicals to V. fischeri were used to investigate the modes of action (MOAs) between species. The results show that although there is a positive interspecies correlation, the relationship is poor. Analysis on the excess toxicity calculated from toxic ratios (TR) shows that many chemicals have close toxicities and share the same MOAs between the two species. Linear relationships between the toxicities and octanol/water partition coefficient (log KOW) for baseline and less inert compounds indicate that the internal critical concentrations (CBRs) approach a constant both to fish and V. fischeri for neutral hydrophobic compounds. These compounds share the same toxic mechanisms and bio-uptake processes between species. On the other hand, some hydrophilic compounds exhibit different toxic effects with greatly different log TR values between V. fischeri and fish species. These hydrophilic compounds were identified as reactive MOAs to V. fischeri, but not to fish. The interspecies correlation is improved by adding a hydrophobic descriptor into the correlation equation. This indicates that the differences in the toxic ratios between fish and V. fischeri for these hydrophilic compounds can be partly attributed to the differences of bioconcentration between the two species, rather than the differences of reactivity with the target macromolecules. These hydrophilic compounds may more easily pass through the cell membrane of V. fischeri than the gill and skin of fish, react with the target macromolecules and exhibit excess toxicity. The compounds with log KOW > 7 exhibiting very low toxicity (log TR < –1) to both species indicate that the bioconcentration potential of a chemical plays a very important role in the identification of excess toxicity and MOAs
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Wang, Zhuo; Liu, Jian-Qun; Xu, Jin-Di; Zhu, He; Kong, Ming; Zhang, Guo-Hua; Duan, Su-Min; Li, Xiu-Yang; Li, Guang-Fu; Liu, Li-Fang; Li, Song-Lin
2017-06-01
Triptolide (TP) from Tripterygium wilfordii has been demonstrated to possess anti-inflammatory, immunosuppressive, and anticancer activities. TP is specially used for the treatment of awkward rheumatoid arthritis, but its clinical application is confined by intense side effects. It is reported that licorice can obviously reduce the toxicity of TP, but the detailed mechanisms involved have not been comprehensively investigated. The current study aimed to explore metabolomics characteristics of the toxic reaction induced by TP and the intervention effect of licorice water extraction (LWE) against such toxicity. Obtained urine samples from control, TP and TP + LWE treated rats were analyzed by UPLC/ESI-QTOF-MS. The metabolic profiles of the control and the TP group were well differentiated by the principal component analysis and orthogonal partial least squares-discriminant analysis. The toxicity of TP was demonstrated to be evolving along with the exposure time of TP. Eight potential biomarkers related to TP toxicity were successfully identified in urine samples. Furthermore, LWE treatment could attenuate the change in six of the eight identified biomarkers. Functional pathway analysis revealed that the alterations in these metabolites were associated with tryptophan, pantothenic acid, and porphyrin metabolism. Therefore, it was concluded that LWE demonstrated interventional effects on TP toxicity through regulation of tryptophan, pantothenic acid, and porphyrin metabolism pathways, which provided novel insights into the possible mechanisms of TP toxicity as well as the potential therapeutic effects of LWE against such toxicity. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.
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Smith, Kathleen S.; Ranville, James F.; Lesher, Emily K.; Diedrich, Daniel J.; McKnight, Diane M.; Sofield, Ruth M.
2014-01-01
This study examines the effect on aquatic copper toxicity of the chemical fractionation of fulvic acid (FA) that results from its association with iron and aluminum oxyhydroxide precipitates. Fractionated and unfractionated FAs obtained from streamwater and suspended sediment were utilized in acute Cu toxicity tests on ,i>Ceriodaphnia dubia. Toxicity test results with equal FA concentrations (6 mg FA/L) show that the fractionated dissolved FA was 3 times less effective at reducing Cu toxicity (EC50 13 ± 0.6 μg Cu/L) than were the unfractionated dissolved FAs (EC50 39 ± 0.4 and 41 ± 1.2 μg Cu/L). The fractionation is a consequence of preferential sorption of molecules having strong metal-binding (more aromatic) moieties to precipitating Fe- and Al-rich oxyhydroxides, causing the remaining dissolved FA to be depleted in these functional groups. As a result, there is more bioavailable dissolved Cu in the water and hence greater potential for Cu toxicity to aquatic organisms. In predicting Cu toxicity, biotic ligand models (BLMs) take into account dissolved organic carbon (DOC) concentration; however, unless DOC characteristics are accounted for, model predictions can underestimate acute Cu toxicity for water containing fractionated dissolved FA. This may have implications for water-quality criteria in systems containing Fe- and Al-rich sediment, and in mined and mineralized areas in particular. Optical measurements, such as specific ultraviolet absorbance at 254 nm (SUVA254), show promise for use as spectral indicators of DOC chemical fractionation and inferred increased Cu toxicity.
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Bruner, L H; Carr, G J; Harbell, J W; Curren, R D
2002-06-01
specificity equal to approximately 1) indicate lack of predictive capacity, an NTM having these performance characteristics should be considered no better for predicting toxicity than by chance alone.
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Acute toxicity of an acid mine drainage mixing zone to juvenile bluegill and largemouth bass
Henry, T.B.; Irwin, E.R.; Grizzle, J.M.; Wildhaber, M.L.; Brumbaugh, W.G.
1999-01-01
The toxicity of an acid mixing zone produced at the confluence of a stream that was contaminated by acid mine drainage (AMD) and a pH-neutral stream was investigated in toxicity tests with juvenile bluegill Lepomis macrochirus and largemouth bass Micropterus salmoides. Fish mortalities in instream cages located in the mixing zone, below the mixing zone, and upstream in both tributaries were compared to determine relative toxicity at each site. In all tests and for both species, significantly higher mortality was observed in the mixing zone than at any other location, including the acid stream, which had lower pH (2.9-4.3). The mixing zone was defined chemically by rapid precipitation of dissolved aluminum and iron, which arrived from the low-pH stream, and by the presence of white precipitates, which were attached to the substratum and which extended below the confluence. Possible seasonal changes in mixing zone toxicity were investigated by conducting field tests with bluegill in June, July, and August 1996 and in January 1997 and by conducting field tests with largemouth bass in April and May 1997. Toxicity was not significantly different at the extremes of temperature, pH, and metal concentration that occurred in June and July, as compared with January. Toxicity was significantly lower in August; however, elevated stream discharge during the August test may have disturbed mixing zone characteristics. High toxicity in AMD mixing zones may lower the survival of fishes in streams, reduce available habitat, and impede movements of migratory fish.
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Marrouchi, Riadh; Benoit, Evelyne; Le Caer, Jean-Pierre; Belayouni, Nawel; Belghith, Hafedh; Molgó, Jordi; Kharrat, Riadh
2013-01-01
Severe toxicity was detected in mussels from Bizerte Lagoon (Northern Tunisia) using routine mouse bioassays for detecting diarrheic and paralytic toxins not associated to classical phytoplankton blooming. The atypical toxicity was characterized by rapid mouse death. The aim of the present work was to understand the basis of such toxicity. Bioassay-guided chromatographic separation and mass spectrometry were used to detect and characterize the fraction responsible for mussels’ toxicity. Only a C17-sphinganine analog mycotoxin (C17-SAMT), with a molecular mass of 287.289 Da, was found in contaminated shellfish. The doses of C17-SAMT that were lethal to 50% of mice were 750 and 150 μg/kg following intraperitoneal and intracerebroventricular injections, respectively, and 900 μg/kg following oral administration. The macroscopic general aspect of cultures and the morphological characteristics of the strains isolated from mussels revealed that the toxicity episodes were associated to the presence of marine microfungi (Fusarium sp., Aspergillus sp. and Trichoderma sp.) in contaminated samples. The major in vivo effect of C17-SAMT on the mouse neuromuscular system was a dose- and time-dependent decrease of compound muscle action potential amplitude and an increased excitability threshold. In vitro, C17-SAMT caused a dose- and time-dependent block of directly- and indirectly-elicited isometric contraction of isolated mouse hemidiaphragms. PMID:24287956
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Economou, Anastasios
2018-03-29
This work reviews the field of screen-printed electrodes (SPEs) modified with "green" metals for electrochemical stripping analysis of toxic elements. Electrochemical stripping analysis has been established as a useful trace analysis technique offering many advantages compared to competing optical techniques. Although mercury has been the preferred electrode material for stripping analysis, the toxicity of mercury and the associated legal requirements in its use and disposal have prompted research towards the development of "green" metals as alternative electrode materials. When combined with the screen-printing technology, such environment-friendly metals can lead to disposable sensors for trace metal analysis with excellent operational characteristics. This review focuses on SPEs modified with Au, Bi, Sb, and Sn for stripping analysis of toxic elements. Different modification approaches (electroplating, bulk modification, use of metal precursors, microengineering techniques) are considered and representative applications are described. A developing related field, namely biosensing based on stripping analysis of metallic nanoprobe labels, is also briefly mentioned.
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EVALUATION OF ALTERNATIVE REFERENCE TOXICANTS FOR USE IN THE EARTHWORM TOXICITY TEST
The use of the 14-d earthworm toxicity test to aid in the evaluation of the ecological impact of contaminated soils is becoming increasingly widespread. However,the method is in need of further standardization. As part of this continuing process, the choice of reference toxicants...
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Toxicity Assessment of the Xanthid Crab Demania cultripes from Cebu Island, Philippines
Asakawa, Manabu; Gomez-Delan, Gloria; Tsuruda, Shintaro; Shimomura, Michitaka; Shida, Yasuo; Taniyama, Shigeto; Barte-Quilantang, Mercy; Shindo, Jo
2010-01-01
Several cases of poisoning resulting in human fatalities and stemming from the ingestion of coral reef crabs have been reported from the Indo-Pacific region. We assessed the toxicity of the unidentified xanthid crab collected from the Camotes Sea off the eastern coast of Cebu Island, central Visayas region of Philippines from the food hygienic point of view. All seven specimens, which were identified with Demania cultripes, collected in 2006 were toxic to mice irrespective of the season of collection and induced paralytic symptoms typical of tetrodotoxin (TTX) and paralytic shellfish poison (PSP). The activity was expressed in mouse unit (MU) being defined as the amount of TTX to kill a 20 g ddY male mice in 30 min after i.p. injection. Toxicity scores for viscera and appendages of specimens were 18.2 ± 16.0 (mean ± S.D.) and 4.4 ± 2.6 MU/g, respectively. The highest individual toxicity scores observed for viscera and appendages were 52.1 and 7.7 MU/g, respectively. The frequency of toxic samples was 100%. Toxin profiles as determined by high-performance liquid chromatography-fluorescent detection analysis (HPLC-FLD) revealed that TTX was the main toxic principle accounting for about 90% of the total toxicity along with 4-epi TTX and 4,9-anhydroTTX. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis revealed mass fragment ion peaks at m/z 376, 392 and 407, which were characteristic of the quinazoline skeleton (C9-base) specific to TTX. In addition, only a small amount of PSP containing gonyautoxins1–4 and hydroxysaxitoxin was detected. To our knowledge, this is the first report presenting evidence of occurrence of TTX and PSP in the xanthid crab D. cultripes inhabiting waters surrounding Cebu Island. From food hygienic point of view, people in coastal areas should be warned of the potential hazard of this crab in order to prevent its intentional or accidental consumption. PMID:21209702
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Whole Effluent Toxicity (WET) describes the aggregate toxic effect of an aqueous sample (e.g., whole effluent wastewater discharge) as measured by an organism's response upon exposure to the sample (e.g., lethality, impaired growth, or reproduction).
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Toxicity of food-relevant nanoparticles in intestinal epithelial models
NASA Astrophysics Data System (ADS)
McCracken, Christie
Nanoparticles are increasingly being incorporated into common consumer products, including in foods and food packaging, for their unique properties at the nanoscale. Food-grade silica and titania are used as anti-caking and whitening agents, respectively, and these particle size distributions are composed of approximately one-third nanoparticles. Zinc oxide and silver nanoparticles can be used for their antimicrobial properties. However, little is known about the interactions of nanoparticles in the body upon ingestion. This study was performed to investigate the role of nanoparticle characteristics including surface chemistry, dissolution, and material type on toxicity to the intestinal epithelium. Only mild acute toxicity of zinc oxide nanoparticles was observed after 24-hour treatment of intestinal epithelial C2BBe1 cells based on the results of toxicity assays measuring necrosis, apoptosis, membrane damage, and mitochondrial activity. Silica and titanium dioxide nanoparticles were not observed to be toxic although all nanoparticles were internalized by cells. In vitro digestion of nanoparticles in solutions representing the stomach and intestines prior to treatment of cells did not alter nanoparticle toxicity. Long-term repeated treatment of cells weekly for 24 hours with nanoparticles did not change nanoparticle cytotoxicity or the growth rate of the treated cell populations. Thus, silica, titanium dioxide, and zinc oxide nanoparticles were found to induce little toxicity in intestinal epithelial cells. Fluorescent silica nanoparticles were synthesized as a model for silica used in foods that could be tracked in vitro and in vivo. To maintain an exterior of pure silica, a silica shell was hydrolyzed around a core particle of quantum dots or a fluorescent dye electrostatically associated with a commercial silica particle. The quantum dots used were optimized from a previously reported microwave quantum dot synthesis to a quantum yield of 40%. Characterization
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"Non-Toxic" Proteins of the Botulinum Toxin Complex Exert In-vivo Toxicity.
Miyashita, Shin-Ichiro; Sagane, Yoshimasa; Suzuki, Tomonori; Matsumoto, Takashi; Niwa, Koichi; Watanabe, Toshihiro
2016-08-10
The botulinum neurotoxin (BoNT) causes muscle paralysis and is the most potent toxin in nature. BoNT is associated with a complex of auxiliary "Non-Toxic" proteins, which constitute a large-sized toxin complex (L-TC). However, here we report that the "Non-Toxic" complex of serotype D botulinum L-TC, when administered to rats, exerts in-vivo toxicity on small-intestinal villi. Moreover, Serotype C and D of the "Non-Toxic" complex, but not BoNT, induced vacuole-formation in a rat intestinal epithelial cell line (IEC-6), resulting in cell death. Our results suggest that the vacuole was formed in a manner distinct from the mechanism by which Helicobacter pylori vacuolating toxin (VacA) and Vibrio cholerae haemolysin induce vacuolation. We therefore hypothesise that the serotype C and D botulinum toxin complex is a functional hybrid of the neurotoxin and vacuolating toxin (VT) which arose from horizontal gene transfer from an ancestral BoNT-producing bacterium to a hypothetical VT-producing bacterium.
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CORMIX is a series of software systems for the analysis, prediction, and design of aqueous toxic or conventional pollutant discharges into watercourses, with emphasis on the geometry and dilution characteristics of the initial mixing zone. ubsystem CORMIX1 deals with submerged si...
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Maternally Mediated Developmental Toxicity
The current practice for the assessment of an agent’s potential effects on the developing embryo/fetus includes administration of high, maternally toxic doses to pregnant laboratory animals. For most agents evaluated, developmental effects occur concomitant with maternal toxicity...
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Analysis of Toxic and Non-Toxic Alexandrium (Dinophyceae) Species Using Ribosomal RNA Gene Sequences
1993-02-01
Therriault, J.-C. (1988). Cladistic analysis of electrophoretic variants within the toxic dinoflagellate genus Protogonyaulax. Botanica Marina 31: 39- 51. 8... Botanica Marina 34: 575-587. Halegraeff, G. M., and Bolch, C.J. (1992). Transport of toxic dinoflagellate cysts via ship’s ballast water: implications...analysis of electrophoretic variants within the toxic dinoflagellate genus Protogonv-u.!a,. Botanica Marina 31: 39-51. Curran, J., Baillie, D.L
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Iron Promotes the Toxicity of Amyloid β Peptide by Impeding Its Ordered Aggregation*
Liu, Beinan; Moloney, Aileen; Meehan, Sarah; Morris, Kyle; Thomas, Sally E.; Serpell, Louise C.; Hider, Robert; Marciniak, Stefan J.; Lomas, David A.; Crowther, Damian C.
2011-01-01
We have previously shown that overexpressing subunits of the iron-binding protein ferritin can rescue the toxicity of the amyloid β (Aβ) peptide in our Drosophila model system. These data point to an important pathogenic role for iron in Alzheimer disease. In this study, we have used an iron-selective chelating compound and RNAi-mediated knockdown of endogenous ferritin to further manipulate iron in the brain. We confirm that chelation of iron protects the fly from the harmful effects of Aβ. To understand the pathogenic mechanisms, we have used biophysical techniques to see how iron affects Aβ aggregation. We find that iron slows the progression of the Aβ peptide from an unstructured conformation to the ordered cross-β fibrils that are characteristic of amyloid. Finally, using mammalian cell culture systems, we have shown that iron specifically enhances Aβ toxicity but only if the metal is present throughout the aggregation process. These data support the hypothesis that iron delays the formation of well ordered aggregates of Aβ and so promotes its toxicity in Alzheimer disease. PMID:21147772
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Iron promotes the toxicity of amyloid beta peptide by impeding its ordered aggregation.
Liu, Beinan; Moloney, Aileen; Meehan, Sarah; Morris, Kyle; Thomas, Sally E; Serpell, Louise C; Hider, Robert; Marciniak, Stefan J; Lomas, David A; Crowther, Damian C
2011-02-11
We have previously shown that overexpressing subunits of the iron-binding protein ferritin can rescue the toxicity of the amyloid β (Aβ) peptide in our Drosophila model system. These data point to an important pathogenic role for iron in Alzheimer disease. In this study, we have used an iron-selective chelating compound and RNAi-mediated knockdown of endogenous ferritin to further manipulate iron in the brain. We confirm that chelation of iron protects the fly from the harmful effects of Aβ. To understand the pathogenic mechanisms, we have used biophysical techniques to see how iron affects Aβ aggregation. We find that iron slows the progression of the Aβ peptide from an unstructured conformation to the ordered cross-β fibrils that are characteristic of amyloid. Finally, using mammalian cell culture systems, we have shown that iron specifically enhances Aβ toxicity but only if the metal is present throughout the aggregation process. These data support the hypothesis that iron delays the formation of well ordered aggregates of Aβ and so promotes its toxicity in Alzheimer disease.
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Reduced Toxicity, High Performance Monopropellant at the U.S. Air Force Research Laboratory
NASA Astrophysics Data System (ADS)
Hawkins, T. W.; Brand, A. J.; McKay, M. B.; Tinnirello, M.
2010-09-01
Current programs are aiming to develop reduced toxicity monopropellant formulations to replace spacecraft hydrazine monopropellant. The Air Force Research Laboratory's(AFRL's) approach to replacing hydrazine is the synthesis and development of energetic compounds/formulations with substantially less vapor toxicity and superior performance(specific impulse and density). Characterization and testing of these high energy density materials is an essential part of the screening process for viable advanced propellants. Hazardous handling characteristics, undesirable physical properties or unacceptable sensitivity behaviors must also be identified and/or modified to further development by a potential user. AFRL has successfully identified a novel monopropellant(designated AF-M315E) that shows great promise as an avenue toward replacement of hydrazine monopropellant for spacecraft propulsion. Hazard and safety/sensitivity, stability, and toxicity studies have been conducted on the monopropellant and will be described. The results from AF-M315E indicate that a >50% improvement in propulsion system performance over hydrazine is achievable while simultaneously providing a safer environment for the general public, ground personnel, crews and flight participants.
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Edible lipid nanoparticles: digestion, absorption, and potential toxicity.
McClements, David Julian
2013-10-01
Food-grade nanoemulsions are being increasingly used in the food and beverage industry to encapsulate, protect, and deliver hydrophobic functional components, such as oil-soluble flavors, colors, preservatives, vitamins, and nutraceuticals. These nanoemulsions contain lipid nanoparticles (radius <100 nm) whose physicochemical characteristics (e.g., composition, dimensions, structure, charge, and physical state) can be controlled by selection of appropriate ingredients and fabrication techniques. Nanoemulsions have a number of potential advantages over conventional emulsions for applications within the food industry: higher stability to particle aggregation and gravitational separation; higher optical transparency; and, increased bioavailability of encapsulated components. On the other hand, there are also some risks associated with consumption of lipid nanoparticles that should be considered before they are widely utilized, such as their ability to alter the fate of bioactive components within the gastrointestinal tract and the potential toxicity of some of the components used in their fabrication (e.g., surfactants and organic solvents). This article provides an overview of the current status of the biological fate and potential toxicity of food-grade lipid nanoparticles suitable for utilization within the food and beverage industry. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Traditionally, chronic toxicity in aquatic organisms and wildlife has been determined from either toxicity test data, acute to chronic ratios, or application of safety factors. A more recent alternative approach has been to estimate chronic toxicity by modeling the time course of...
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Toxicity of Uranium Adsorbent Materials using the Microtox Toxicity Test
DOE Office of Scientific and Technical Information (OSTI.GOV)
Park, Jiyeon; Jeters, Robert T.; Gill, Gary A.
2015-10-01
The Marine Sciences Laboratory at the Pacific Northwest National Laboratory evaluated the toxicity of a diverse range of natural and synthetic materials used to extract uranium from seawater. The uranium adsorbent materials are being developed as part of the U. S. Department of Energy, Office of Nuclear Energy, Fuel Resources Program. The goal of this effort was to identify whether deployment of a farm of these materials into the marine environment would have any toxic effects on marine organisms.
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Development of whole sediment toxicity identification and evaluation (TIEs) methods has been under way for approximately four years. These methods are necessary to define cause and effect relationships in toxic sediments during ecological risk assessments, remediation and disposa...
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Baptisia poisoning: a new and toxic look-alike in the neighborhood.
Anderson, Matthew J; Kurtycz, Daniel F I; Cline, Joseph R
2015-01-01
Baptisia is commonly found in residential gardens as an ornamental plant, in municipal "rain gardens" for water control, as well as in native and restored prairie habitat. Cytisine, an alkaloid with nicotinic acetylcholine receptor agonist properties, is a component of Baptisia. Two patients poisoned after simultaneously ingesting Baptisia plant material are presented. In addition to findings of generalized nicotinic agonist toxicity, including generalized weakness and gastrointestinal symptoms, profound ataxia was present in both, consistent with recently described nicotinic subunit activity in the cerebellum. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Baptisia, a native prairie plant commonly found in restored prairie habitats and public spaces, has striking "look-alike" characteristics, in its immature state, to asparagus. As future exposures by foraging citizens will be likely, awareness of this relationship and the toxic manifestations of cytisine will be useful. Copyright © 2015 Elsevier Inc. All rights reserved.
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Safe disposal of toxic chrome buffing dust generated from leather industries.
Swarnalatha, S; Srinivasulu, T; Srimurali, M; Sekaran, G
2008-01-31
The high concentration of trivalent chromium along with organic/inorganic compounds in chrome buffing dust (CBD), the solid waste discharged from leather industries, causes severe groundwater contamination on land co-disposal and chronic air pollution during thermal incineration. In the present investigation, CBD was subjected to starved air incineration (SAI) at 800 degrees C in a thermal incinerator under different flow rates of oxygen to optimize the oxygen required to incinerate the organic compounds and simultaneously preventing the conversion of Cr(3+) to Cr(6+). The energy audit of SAI of buffing dust under the external supply of oxygen was carried out under different incineration conditions. The bottom ash from SAI was effectively solidified/stabilized using Portland cement and fine aggregate. The solidified blocks were tested for unconfined compressive strength and heavy metal leaching. Unconfined compressive strength of the blocks was in the range of 120-180 kg/cm(2). The stabilization of chromium(III) in the cement gel matrix was confirmed using Scanning Electron Microscopy SEM, Electron Paramagnetic Resonance spectroscopy (EPR) and X-ray diffraction spectroscopy (XRD). Leachability studies through TCLP on solidified blocks were carried out to determine the degree of leaching of chromium and organic compounds (expressed as COD) under standard conditions.
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A time-integrated sampling device interfaced with two toxicity-based assays is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethylsulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor...
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Silver Nanowire Exposure Results in Internalization and Toxicity to Daphnia Magna
Scanlan, Leona D.; Reed, Robert B.; Loguinov, Alexandre V.; Antczak, Philipp; Tagmount, Abderrahmane; Aloni, Shaul; Nowinski, Daniel Thomas; Luong, Pauline; Tran, Christine; Karunaratne, Nadeeka; Pham, Don; Lin, Xin Xin; Falciani, Francesco; Higgins, Chris P.; Ranville, James F.; Vulpe, Chris D.; Gilbert, Benjamin
2013-01-01
Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physico-chemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within one-hour following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry (spICPMS) distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy (SEM) imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna. PMID:24099093
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Rohn, Isabelle; Marschall, Talke Anu; Kroepfl, Nina; Jensen, Kenneth Bendix; Aschner, Michael; Tuck, Simon; Kuehnelt, Doris; Schwerdtle, Tanja; Bornhorst, Julia
2018-05-17
The essential micronutrient selenium (Se) is required for various systemic functions, but its beneficial range is narrow and overexposure may result in adverse health effects. Additionally, the chemical form of the ingested selenium contributes crucially to its health effects. While small Se species play a major role in Se metabolism, their toxicological effects, bioavailability and metabolic transformations following elevated uptake are poorly understood. Utilizing the tractable invertebrate Caenorhabditis elegans allowed for an alternative approach to study species-specific characteristics of organic and inorganic Se forms in vivo, revealing remarkable species-dependent differences in the toxicity and bioavailability of selenite, selenomethionine (SeMet) and Se-methylselenocysteine (MeSeCys). An inverse relationship was found between toxicity and bioavailability of the Se species, with the organic species displaying a higher bioavailability than the inorganic form, yet being less toxic. Quantitative Se speciation analysis with HPLC/mass spectrometry revealed a partial metabolism of SeMet and MeSeCys. In SeMet exposed worms, identified metabolites were Se-adenosylselenomethionine (AdoSeMet) and Se-adenosylselenohomocysteine (AdoSeHcy), while worms exposed to MeSeCys produced Se-methylselenoglutathione (MeSeGSH) and γ-glutamyl-MeSeCys (γ-Glu-MeSeCys). Moreover, the possible role of the sole selenoprotein in the nematode, thioredoxin reductase-1 (TrxR-1), was studied comparing wildtype and trxr-1 deletion mutants. Although a lower basal Se level was detected in trxr-1 mutants, Se toxicity and bioavailability following acute exposure was indistinguishable from wildtype worms. Altogether, the current study demonstrates the suitability of C. elegans as a model for Se species dependent toxicity and metabolism, while further research is needed to elucidate TrxR-1 function in the nematode.
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Jho, Eun Hea; Im, Jinwoo; Yang, Kyung; Kim, Young-Jin; Nam, Kyoungphile
2015-01-01
This study was set to investigate the changes in the toxicity of arsenic (As)-contaminated soils after washing with phosphate solutions. The soil samples collected from two locations (A: rice paddy and B: forest land) of a former smelter site were contaminated with a similar level of As. Soil washing (0.5 M phosphate solution for 2 h) removed 24.5% As, on average, in soil from both locations. Regardless of soil washing, Location A soil toxicities, determined using Microtox, were greater than that of Location B and this could be largely attributed to different soil particle size distribution. With soils from both locations, the changes in As chemical forms resulted in either similar or greater toxicities after washing. This emphasizes the importance of considering ecotoxicological aspects, which are likely to differ depending on soil particle size distribution and changes in As chemical forms, in addition to the total concentration based remedial goals, in producing ecotoxicologically-sound soils for reuse. In addition, calcium phosphate used as the washing solution seemed to contribute more on the toxic effects of the washed soils than potassium phosphate and ammonium phosphate. Therefore, it would be more appropriate to use potassium or ammonium phosphate than calcium phosphate for phosphate-aided soil washing of the As-contaminated soils. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Mercury stabilization in chemically bonded phosphate ceramics
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wagh, A. S.; Singh, D.; Jeong, S. Y.
2000-04-04
Mercury stabilization and solidification is a significant challenge for conventional stabilization technologies. This is because of the stringent regulatory limits on leaching of its stabilized products. In a conventional cement stabilization process, Hg is converted at high pH to its hydroxide, which is not a very insoluble compound; hence the preferred route for Hg sulfidation to convert it into insoluble cinnabar (HgS). Unfortunately, efficient formation of this compound is pH-dependent. At a high pH, one obtains a more soluble Hg sulfate, in a very low pH range, insufficient immobilization occurs because of the escape of hydrogen sulfide, while efficient formationmore » of HgS occurs only in a moderately acidic region. Thus, the pH range of 4 to 8 is where stabilization with Chemically Bonded Phosphate Ceramics (CBPC) is carried out. This paper discusses the authors experience on bench-scale stabilization of various US Department of Energy (DOE) waste streams containing Hg in the CBPC process. This process was developed to treat DOE's mixed waste streams. It is a room-temperature-setting process based on an acid-base reaction between magnesium oxide and monopotassium phosphate solution that forms a dense ceramic within hours. For Hg stabilization, addition of a small amount (< 1 wt.%) of Na{sub 2}S or K{sub 2}S is sufficient in the binder composition. Here the Toxicity Characteristic Leaching Procedure (TCLP) results on CBPC waste forms of surrogate waste streams representing secondary Hg containing wastes such as combustion residues and Delphi DETOX{trademark} residues are presented. The results show that although the current limit on leaching of Hg is 0.2 mg/L, the results from the CBPC waste forms are at least one order lower than this stringent limit. Encouraged by these results on surrogate wastes, they treated actual low-level Hg-containing mixed waste from their facility at Idaho. TCLP results on this waste are presented here. The efficient
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Novotny, A.N.; Ezzard, C.L.; Douglas, W.S.
1995-12-31
The IQ Toxicity Test, which is a rapid screening toxicity test consisting of the observation of in-vivo inhibition of an enzymatic process using a fluorescent substrate, has proven successful for the determination of 24 and 48-hour EC50`s of D. magna, C. dubia, D. pulex and M. bahia. The application of this concept to utilize the freshwater amphipod Hyalella azteca may be an excellent way in which to reduce the standard 28-day chronic sediment toxicity test to possibly one hour`s time. This study incorporates an additive experimental design to explore the effects of and interactions between five specific variables: size ofmore » the amphipod, exposure time to the toxicant, concentration of substrate, exposure time to the substrate, and length of time starved prior to testing. The results of the IQ toxicity test were compared to those of a 28-day chronic sediment toxicity test. Preliminary data indicate that there is an optimal combination of these variables which results in a concise, reproducible toxicity test for use with Hyalella azteca, and would potentially be applicable to other freshwater amphipods in the future.« less
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The influence of genetic variation on late toxicities in childhood cancer survivors: A review.
Clemens, E; van der Kooi, A L F; Broer, L; van Dulmen-den Broeder, E; Visscher, H; Kremer, L; Tissing, W; Loonen, J; Ronckers, C M; Pluijm, S M F; Neggers, S J C M M; Zolk, O; Langer, T; Zehnhoff-Dinnesen, A Am; Wilson, C L; Hudson, M M; Carleton, B; Laven, J S E; Uitterlinden, A G; van den Heuvel-Eibrink, M M
2018-06-01
The variability in late toxicities among childhood cancer survivors (CCS) is only partially explained by treatment and baseline patient characteristics. Inter-individual variability in the association between treatment exposure and risk of late toxicity suggests that genetic variation possibly modifies this association. We reviewed the available literature on genetic susceptibility of late toxicity after childhood cancer treatment related to components of metabolic syndrome, bone mineral density, gonadal impairment and hearing impairment. A systematic literature search was performed, using Embase, Cochrane Library, Google Scholar, MEDLINE, and Web of Science databases. Eligible publications included all English language reports of candidate gene studies and genome wide association studies (GWAS) that aimed to identify genetic risk factors associated with the four late toxicities, defined as toxicity present after end of treatment. Twenty-seven articles were identified, including 26 candidate gene studies: metabolic syndrome (n = 6); BMD (n = 6); gonadal impairment (n = 2); hearing impairment (n = 12) and one GWAS (metabolic syndrome). Eighty percent of the genetic studies on late toxicity after childhood cancer had relatively small sample sizes (n < 200), leading to insufficient power, and lacked adjustment for multiple comparisons. Only four (4/26 = 15%) candidate gene studies had their findings validated in independent replication cohorts as part of their own report. Genetic susceptibility associations are not consistent or not replicated and therefore, currently no evidence-based recommendations can be made for hearing impairment, gonadal impairment, bone mineral density impairment and metabolic syndrome in CCS. To advance knowledge related to genetic variation influencing late toxicities among CCS, future studies need adequate power, independent cohorts for replication, harmonization of disease outcomes and sample collections, and
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Toxic effects of triazophos on rare minnow (Gobiocypris rarus) embryos and larvae.
Zhu, Bin; Gong, Yu-Xin; Liu, Lei; Li, Dong-Liang; Wang, Yuan; Ling, Fei; Wang, Gao-Xue
2014-08-01
Triazophos (TAP) has been widely used in agriculture for controlling insect pests and is a known organophosphorus pesticide. Due to TAP characteristics, such as high chemical and photochemical stability, its potential toxicity to aquatic organisms has gained great interest. To explore the potential developmental toxicity of TAP, Gobiocypris rarus embryos and larvae were exposed to various concentrations of TAP (0.1-15 mg L(-1)) until 72 h. Results showed that values of 72 h LC50 and EC50 were 7.44 and 5.60 mg L(-1) for embryos, 2.52 and 1.37 mg L(-1) for larvae. Increased malformation, decreased heart rate and body length provide a gradual concentration-dependent pattern. Enzyme activities and mRNA levels were significantly changed even at low concentration (0.05 mg L(-1) for embryos and 0.01 mg L(-(1) for larvae). Overall, the present study points out that TAP is likely a risk to the early development of G. rarus. The information presented in this study will be helpful in better understanding the toxicity induced by TAP in fish embryos and larvae. Copyright © 2014 Elsevier Ltd. All rights reserved.
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2012-12-14
labeled as toxic, can he or she be rehabilitated?; Are there leadership styles that can be promoted to combat toxic leadership?; and Are the senior...examines leadership styles that are favorable for female leaders, and offers Transformational/Adaptive leadership as a style promising rehabilitative tools
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The Effect of Toxic Leadership
2012-03-15
traits) and not the disease (culture, climate, outcomes ).3 Several researchers agree that the long-term negative effect that toxic leaders have on an...The Effect of Toxic Leadership by Lieutenant Colonel Darrell W. Aubrey United States Army United States Army War...The Effect of Toxic Leadership 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Lieutenant
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Structural basis of membrane disruption and cellular toxicity by α-synuclein oligomers.
Fusco, Giuliana; Chen, Serene W; Williamson, Philip T F; Cascella, Roberta; Perni, Michele; Jarvis, James A; Cecchi, Cristina; Vendruscolo, Michele; Chiti, Fabrizio; Cremades, Nunilo; Ying, Liming; Dobson, Christopher M; De Simone, Alfonso
2017-12-15
Oligomeric species populated during the aggregation process of α-synuclein have been linked to neuronal impairment in Parkinson's disease and related neurodegenerative disorders. By using solution and solid-state nuclear magnetic resonance techniques in conjunction with other structural methods, we identified the fundamental characteristics that enable toxic α-synuclein oligomers to perturb biological membranes and disrupt cellular function; these include a highly lipophilic element that promotes strong membrane interactions and a structured region that inserts into lipid bilayers and disrupts their integrity. In support of these conclusions, mutations that target the region that promotes strong membrane interactions by α-synuclein oligomers suppressed their toxicity in neuroblastoma cells and primary cortical neurons. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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NASA Technical Reports Server (NTRS)
Morgan, E. L.; Young, R. C.; Smith, M. D.; Eagleson, K. W.
1986-01-01
The objective of this study was to evaluate proposed design characteristics and applications of automated biomonitoring devices for real-time toxicity detection in water quality control on-board permanent space stations. Simulated tests in downlinking transmissions of automated biomonitoring data to Earth-receiving stations were simulated using satellite data transmissions from remote Earth-based stations.
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Madadi, Parvaz; Hildebrandt, Doris; Lauwers, Albert E; Koren, Gideon
2013-01-01
The impact of the prescription opioid public health crisis has been illustrated by the dramatic increase in opioid-related deaths in North America. We aimed to identify patterns and characteristics amongst opioid-users whose cause of death was related to opioid toxicity. This was a population-based study of Ontarians between the years 2006 and 2008. All drug-related deaths which occurred during this time frame were reviewed at the Office of the Chief Coroner of Ontario, and opioid-related deaths were identified. Medical, toxicology, pathology, and police reports were comprehensively reviewed. Narratives, semi-quantitative, and quantitative variables were extracted, tabulated, and analyzed. Out of 2330 drug-related deaths in Ontario, 58% were attributed either in whole or in part, to opioids (n = 1359). Oxycodone was involved in approximately one-third of all opioid-related deaths. At least 7% of the entire cohort used opioids that were prescribed for friends and/or family, 19% inappropriately self-administered opioids (injection, inhalation, chewed patch), 3% were recently released from jail, and 5% had been switched from one opioid to another near the time of death. Accidental deaths were significantly associated with personal history of substance abuse, enrollment in methadone maintenance programs, cirrhosis, hepatitis, and cocaine use. Suicides were significantly associated with mental illness, previous suicide attempts, chronic pain, and a history of cancer. These results identify novel, susceptible groups of opioid-users whose cause of death was related to opioids in Ontario and provide the first evidence to assist in quantifying the contribution of opioid misuse and diversion amongst opioid-related mortality in Canada. Multifaceted prevention strategies need to be developed based on subpopulations of opioid users.
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Reduced Toxicity Fuel Satellite Propulsion System
NASA Technical Reports Server (NTRS)
Schneider, Steven J. (Inventor)
2001-01-01
A reduced toxicity fuel satellite propulsion system including a reduced toxicity propellant supply for consumption in an axial class thruster and an ACS class thruster. The system includes suitable valves and conduits for supplying the reduced toxicity propellant to the ACS decomposing element of an ACS thruster. The ACS decomposing element is operative to decompose the reduced toxicity propellant into hot propulsive gases. In addition the system includes suitable valves and conduits for supplying the reduced toxicity propellant to an axial decomposing element of the axial thruster. The axial decomposing element is operative to decompose the reduced toxicity propellant into hot gases. The system further includes suitable valves and conduits for supplying a second propellant to a combustion chamber of the axial thruster, whereby the hot gases and the second propellant auto-ignite and begin the combustion process for producing thrust.
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Van Cott, Andrew; Hastings, Charles E; Landsiedel, Robert; Kolle, Susanne; Stinchcombe, Stefan
2018-02-01
In vivo acute systemic testing is a regulatory requirement for agrochemical formulations. GHS specifies an alternative computational approach (GHS additivity formula) for calculating the acute toxicity of mixtures. We collected acute systemic toxicity data from formulations that contained one of several acutely-toxic active ingredients. The resulting acute data set includes 210 formulations tested for oral toxicity, 128 formulations tested for inhalation toxicity and 31 formulations tested for dermal toxicity. The GHS additivity formula was applied to each of these formulations and compared with the experimental in vivo result. In the acute oral assay, the GHS additivity formula misclassified 110 formulations using the GHS classification criteria (48% accuracy) and 119 formulations using the USEPA classification criteria (43% accuracy). With acute inhalation, the GHS additivity formula misclassified 50 formulations using the GHS classification criteria (61% accuracy) and 34 formulations using the USEPA classification criteria (73% accuracy). For acute dermal toxicity, the GHS additivity formula misclassified 16 formulations using the GHS classification criteria (48% accuracy) and 20 formulations using the USEPA classification criteria (36% accuracy). This data indicates the acute systemic toxicity of many formulations is not the sum of the ingredients' toxicity (additivity); but rather, ingredients in a formulation can interact to result in lower or higher toxicity than predicted by the GHS additivity formula. Copyright © 2018 Elsevier Inc. All rights reserved.
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Kleinstreuer, Clement; Feng, Yu
2013-09-23
Inhaled toxic aerosols of conventional cigarette smoke may impact not only the health of smokers, but also those exposed to second-stream smoke, especially children. Thus, less harmful cigarettes (LHCs), also called potential reduced exposure products (PREPs), or modified risk tobacco products (MRTP) have been designed by tobacco manufacturers to focus on the reduction of the concentration of carcinogenic components and toxicants in tobacco. However, some studies have pointed out that the new cigarette products may be actually more harmful than the conventional ones due to variations in puffing or post-puffing behavior, different physical and chemical characteristics of inhaled toxic aerosols, and longer exposure conditions. In order to understand the toxicological impact of tobacco smoke, it is essential for scientists, engineers and manufacturers to develop experiments, clinical investigations, and predictive numerical models for tracking the intake and deposition of toxicants of both LHCs and conventional cigarettes. Furthermore, to link inhaled toxicants to lung and other diseases, it is necessary to determine the physical mechanisms and parameters that have significant impacts on droplet/vapor transport and deposition. Complex mechanisms include droplet coagulation, hygroscopic growth, condensation and evaporation, vapor formation and changes in composition. Of interest are also different puffing behavior, smoke inlet conditions, subject geometries, and mass transfer of deposited material into systemic regions. This review article is intended to serve as an overview of contributions mainly published between 2009 and 2013, focusing on the potential health risks of toxicants in cigarette smoke, progress made in different approaches of impact analyses for inhaled toxic aerosols, as well as challenges and future directions.
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Gensemer, Robert W; Naddy, Rami B; Stubblefield, William A; Hockett, J Russell; Santore, Robert; Paquin, Paul
2002-09-01
The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States over the range of 25-400 mgl(-1) (as CaCO(3)). However, waters in the arid west of the US frequently exceed 400 mgl(-1) hardness, and the applicability of hardness-toxicity relationships in these waters is unknown. Acute toxicity tests with Ceriodaphnia dubia were conducted at hardness levels ranging from approximately 300 to 1,200 mgl(-1) using reconstituted waters that mimic two natural waters with elevated hardness: (1) alkaline desert southwest streams (Las Vegas Wash, NV), and (2) low alkalinity waters from a CaSO(4)-treated mining effluent in Colorado. The moderately-alkaline EPA synthetic hard water was also included for comparison. Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g., alkalinity or other correlated factors). The hardness equations used in regulatory criteria, therefore, may not provide an accurate level of protection against copper toxicity in all types of very hard waters. However, the mechanistic Biotic ligand model generally predicted copper toxicity within +/-2X of observed EC(50) values, and thus may be more useful than hardness for modifying water quality criteria.
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VanLandeghem, Matthew M.; Farooqi, Mukhtar; Southard, Greg M.; Patino, Reynaldo
2015-01-01
Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity-related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga.
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Economou, Anastasios
2018-01-01
This work reviews the field of screen-printed electrodes (SPEs) modified with “green” metals for electrochemical stripping analysis of toxic elements. Electrochemical stripping analysis has been established as a useful trace analysis technique offering many advantages compared to competing optical techniques. Although mercury has been the preferred electrode material for stripping analysis, the toxicity of mercury and the associated legal requirements in its use and disposal have prompted research towards the development of “green” metals as alternative electrode materials. When combined with the screen-printing technology, such environment-friendly metals can lead to disposable sensors for trace metal analysis with excellent operational characteristics. This review focuses on SPEs modified with Au, Bi, Sb, and Sn for stripping analysis of toxic elements. Different modification approaches (electroplating, bulk modification, use of metal precursors, microengineering techniques) are considered and representative applications are described. A developing related field, namely biosensing based on stripping analysis of metallic nanoprobe labels, is also briefly mentioned. PMID:29596391
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Wright, Jean L., E-mail: jwrigh71@jhmi.edu; Takita, Cristiane; Reis, Isildinha M.
2014-10-01
Purpose: Radiation-induced skin toxicity is one of the most symptomatic side effects of postmastectomy radiation therapy (PMRT). We sought to determine whether the severity of acute skin toxicity was greater in black patients in a prospective cohort receiving PMRT and to identify other predictors of more severe skin toxicity. Methods and Materials: We evaluated the first 110 patients in an ongoing prospective study assessing radiation-induced skin toxicity in patients receiving PMRT. We recorded patient demographics, body mass index (BMI), and disease and treatment characteristics. Logistic regression analyses were conducted to evaluate the effect of potential predictors on the risk ofmore » skin toxicity. Results: A total of 23.6% respondents self-identified as black, 5.5% as non-Hispanic white, 69.1% as Hispanic white, and 1.8% as other; 57% were postmenopausal, and 70.9% had BMI of >25. Median chest wall dose was 50 Gy, and mastectomy scar dose was 60 Gy. Most patients, 95.5%, were treated with a 0.5-cm bolus throughout treatment. There were no significant differences in patient characteristics in black versus non-black patients. At RT completion, moist desquamation was more common in black patients (73.1% vs 47.6%, respectively, P=.023), in postmenopausal patients (63.5% vs 40.4%, respectively, P=.016), and in those with BMI of ≥25 (60.3% vs 37.5%, respectively, P=.030). On multivariate analysis, the effects of black race (odds ratio [OR] = 7.46, P=.031), BMI ≥25 (OR = 2.95, P=.043) and postmenopausal status (OR = 8.26, P=.004) remained significant risk factors for moist desquamation. Conclusions: In this prospectively followed, racially diverse cohort of breast cancer patients receiving PMRT delivered in a uniform fashion, including the routine use of chest wall boost and bolus, black race, higher BMI, and postmenopausal status emerged as significant predictors of moist desquamation. There was a high frequency of moist desquamation, particularly in
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The Toxicity Reference Database (ToxRefDB) contains approximately 30 years and $2 billion worth of animal studies. ToxRefDB allows scientists and the interested public to search and download thousands of animal toxicity testing results for hundreds of chemicals that were previously found only in paper documents. Currently, there are 474 chemicals in ToxRefDB, primarily the data rich pesticide active ingredients, but the number will continue to expand.
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Vincristine toxicity unrelated to dose.
O'Callaghan, M J; Ekert, H
1976-01-01
Four children with vincristine toxicity unrelated to dose are described. Fever, haematological toxicity, and abdominal distension occurred 2-7 days after vincristine was given. Convulsions occurred 6-8 days after vincristine in all 4. Inappropriate secretion of antidiuretic hormone was thought to have occurred in 3 patients. 2 patients died during the acute toxicity phase. Necropsy findings did not show neuronal changes which could be directly ascribed to vincristine. PMID:179476
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Jung, Jee-Hyun; Lee, Eun-Hee; Choi, Kwang-Min; Yim, Un Hyuk; Ha, Sung Yong; An, Joon Geon; Kim, Moonkoo
2017-06-01
Crude oils from distinct geographical regions have distinct chemical compositions, and, as a result, their toxicity may be different. However, developmental toxicity of crude oils derived from different geographical regions has not been extensively characterized. In this study, flounder embryos were separately exposed to effluents contaminated by three crude oils including: Basrah Light (BLO), Pyrenees (PCO), and Sakhalin Vityaz (SVO), in addition to a processed fuel oil (MFO-380), to measure developmental toxicity and for gene expressions. Each oil possessed a distinct chemical composition. Edema defect was highest in embryos exposed to PCO and MFO-380 that both have a greater fraction of three-ring PAHs (33% and 22%, respectively) compared to BLO and SVO. Observed caudal fin defects were higher in embryos exposed to SVO and MFO-380, which are both dominated by naphthalenes (81% and 52%, respectively). CYP1A gene expressions were also highest in embryos exposed to SVO and MFO-380. Higher incidence of cardiotoxicity and lower nkx 2.5 expression were detected in embryos exposed to PCO. Unique gene expression profiles were observed in embryos exposed to crude oils with distinct compositions. This study demonstrates that crude oils of different geographical origins with different compositional characteristics induce developmental toxicity to different degrees. Copyright © 2017 Elsevier Inc. All rights reserved.
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Direct toxicity assessment - Methods, evaluation, interpretation.
Gruiz, Katalin; Fekete-Kertész, Ildikó; Kunglné-Nagy, Zsuzsanna; Hajdu, Csilla; Feigl, Viktória; Vaszita, Emese; Molnár, Mónika
2016-09-01
Direct toxicity assessment (DTA) results provide the scale of the actual adverse effect of contaminated environmental samples. DTA results are used in environmental risk management of contaminated water, soil and waste, without explicitly translating the results into chemical concentration. The end points are the same as in environmental toxicology in general, i.e. inhibition rate, decrease in the growth rate or in yield and the 'no effect' or the 'lowest effect' measurement points of the sample dilution-response curve. The measurement unit cannot be a concentration, since the contaminants and their content in the sample is unknown. Thus toxicity is expressed as the sample proportion causing a certain scale of inhibition or no inhibition. Another option for characterizing the scale of toxicity of an environmental sample is equivalencing. Toxicity equivalencing represents an interpretation tool which enables toxicity of unknown mixtures of chemicals be converted into the concentration of an equivalently toxic reference substance. Toxicity equivalencing, (i.e. expressing the toxicity of unknown contaminants as the concentration of the reference) makes DTA results better understandable for non-ecotoxicologists and other professionals educated and thinking based on the chemical model. This paper describes and discusses the role, the principles, the methodology and the interpretation of direct toxicity assessment (DTA) with the aim to contribute to the understanding of the necessity to integrate DTA results into environmental management of contaminated soil and water. The paper also introduces the benefits of the toxicity equivalency method. The use of DTA is illustrated through two case studies. The first case study focuses on DTA of treated wastewater with the aim to characterize the treatment efficacy of a biological wastewater treatment plant by frequent bioassaying. The second case study applied DTA to investigate the cover layers of two bauxite residue (red mud
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DITOP: drug-induced toxicity related protein database.
Zhang, Jing-Xian; Huang, Wei-Juan; Zeng, Jing-Hua; Huang, Wen-Hui; Wang, Yi; Zhao, Rui; Han, Bu-Cong; Liu, Qing-Feng; Chen, Yu-Zong; Ji, Zhi-Liang
2007-07-01
Drug-induced toxicity related proteins (DITRPs) are proteins that mediate adverse drug reactions (ADRs) or toxicities through their binding to drugs or reactive metabolites. Collection of these proteins facilitates better understanding of the molecular mechanisms of drug-induced toxicity and the rational drug discovery. Drug-induced toxicity related protein database (DITOP) is such a database that is intending to provide comprehensive information of DITRPs. Currently, DITOP contains 1501 records, covering 618 distinct literature-reported DITRPs, 529 drugs/ligands and 418 distinct toxicity terms. These proteins were confirmed experimentally to interact with drugs or their reactive metabolites, thus directly or indirectly cause adverse effects or toxicities. Five major types of drug-induced toxicities or ADRs are included in DITOP, which are the idiosyncratic adverse drug reactions, the dose-dependent toxicities, the drug-drug interactions, the immune-mediated adverse drug effects (IMADEs) and the toxicities caused by genetic susceptibility. Molecular mechanisms underlying the toxicity and cross-links to related resources are also provided while available. Moreover, a series of user-friendly interfaces were designed for flexible retrieval of DITRPs-related information. The DITOP can be accessed freely at http://bioinf.xmu.edu.cn/databases/ADR/index.html. Supplementary data are available at Bioinformatics online.
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Deriving allowable daily intakes for systemic toxicants lacking chronic toxicity data
DOE Office of Scientific and Technical Information (OSTI.GOV)
Layton, D.W.; Mallon, B.J.; Rosenblatt, D.H.
1987-03-01
The lack of human toxicological data for most chemical compounds makes it difficult to quickly assess health risks associated with exposure to contaminants at hazardous waste sites. It would therefore be advantageous to have a technique for estimating acceptable daily intakes (ADIs) of potentially toxic substances based on more widely available animal toxicity data. This article focuses on the use of LD50 data to derive provisional ADIs, and it suggests multiplying oral LD50 values (expressed in mg/kg of body wt) by a factor in the range of 5 X 10(-6) to 1 X 10(-5) day-1 to convert them to suchmore » ADIs. It is emphasized that these interim ADI values are no substitute for toxicity testing, but that such testing would most likely result in higher ADI estimates.« less
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40 CFR 401.15 - Toxic pollutants.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Toxic pollutants. 401.15 Section 401.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PROVISIONS § 401.15 Toxic pollutants. The following comprise the list of toxic pollutants...
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The acute toxicity of local anesthetics.
Mather, Laurence E
2010-11-01
Systemic toxicity, usually from overdose or intravascular dose, is feared because it mainly affects the heart and brain, and may be acutely life-threatening. Pharmacological studies of local anesthetic toxicity have largely been reviewed primarily relating to the evaluation of ropivacaine and levobupivacaine during the past decade. This review/opinion focuses more on the principles and concepts underlying the main models used, from chemical pharmacological and pharmacokinetic perspectives. Research models required to produce pivotal toxicity data are discussed. The potencies for neural blockade and systemic toxicity are associated across virtually all models, with some deviations through molecular stereochemistry. These models show that all local anesthetics can produce direct cardiovascular system toxicity and CNS excitotoxicity that may further affect the cardiovascular system response. Whereas the longer-acting local anesthetics are more likely to cause cardiac death by malignant arrhythmias, the shorter-acting agents are more likely to cause cardiac contraction failure. In most models, equi-anesthetic doses of ropivacaine and levobupivacaine are less likely to produce serious toxicity than bupivacaine. Of the various models, this reviewer favors a whole-body large animal preparation because of the comprehensive data collection possible. The conscious sheep preparation has contributed more than any other, and may be regarded as the de facto 'standard' experimental model for concurrent study of local anesthetic toxicity ± pharmacokinetics, using experimental designs that can reproduce the toxicity seen in clinical accidents.
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Toxic Picoplanktonic Cyanobacteria—Review
Jakubowska, Natalia; Szeląg-Wasielewska, Elżbieta
2015-01-01
Cyanobacteria of a picoplanktonic cell size (0.2 to 2.0 µm) are common organisms of both freshwater and marine ecosystems. However, due to their small size and relatively short study history, picoplanktonic cyanobacteria, in contrast to the microplanktonic cyanobacteria, still remains a poorly studied fraction of plankton. So far, only little information on picocyanobacteria toxicity has been reported, while the number of reports concerning their presence in ecosystems is increasing. Thus, the issue of picocyanobacteria toxicity needs more researchers’ attention and interest. In this report, we present information on the current knowledge concerning the picocyanobacteria toxicity, as well as their harmfulness and problems they can cause. PMID:25793428
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Multigeneration reproduction studies are used to characterize parental and offspring systemic toxicity, as well as reproductive toxicity of pesticides, industrial chemicals and pharmaceuticals. Results from 329 multigeneration studies on 316 chemicals have been digitized into sta...
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Thermal Stress and Toxicity | Science Inventory | US EPA
Elevating ambient temperature above thermoneutrality exacerbates toxicity of most air pollutants, insecticides, and other toxic chemicals. On the other hand, safety and toxicity testing of toxicants and drugs is usually performed in mice and rats maintained at subthermoneutral temperatures of —22 °C. When exposed to chemical toxicants under these relatively cool conditions, rodents typically undergo a regulated hypothermic response, characterized by preference for cooler ambient temperatures and controlled reduction in core temperature. Reducing core temperature delays the clearance of most toxicants from the body; however, a mild hypothermia also improves recovery and survival from the toxicant. Raising ambient temperature to thermoneutrality and above increases the rate of clearance of the toxicant but also exacerbates toxicity. Furthermore, heat stress combined with work or exercise is likely to worsen toxicity. Body temperature of large mammals, including humans, does not decrease as much in response to exposure to a toxicant. However, heat stress tan nonetheless worsen toxic outcome in humans through a variety of mechanisms. For example, heat-induced sweating and elevation in skin blood flow accelerates uptake of some insecticides. Epidemiological studies suggest that thermal stress may exacerbate the toxicity of airborne pollutants such as ozone and particulate matter. Overall, translating results of studies in rodents to that of humans is a formidable
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Rodriguez-Vicente, J; Vicente-Ortega, V; Canteras-Jordana, M; Calderon-Rubiales, F
1997-10-01
We studied the response of mouse B16F10 and SK-MEL-28 and SK-MEL-1 human melanoma cell lines to treatment with 4-hydroxyanisole (4-HA), and attempted to relate the response to the dopa oxidase levels and the morphological characteristics of each cell line. Clear dose-response curves were observed after 24 h of treatment in each cell line, the 4-HA being more toxic to the B16F10 cells, with an ID50 value of 215 microM. This was much lower than that observed for the SK-MEL-28 and SK-MEL-1 cell lines (ID50 of 5.98 mM and 7.17 mM, respectively). There was a direct relationship between toxicity levels and dopa oxidase activity, since the highest specific activity was obtained for B16F10 (15.9 mU), while lower activity was registered for SK-MEL-28 (4.59 mU) and SK-MEL-1 (1.24 mU), which also showed lower 4-HA toxicity. Morphologically, we observed the typical characteristics of cellular injury, with swelling and dilation of the internal membranes and organelles, an increased number of vacuoles, and an increased number of abnormal multilamellar melanosomes or thick clumps of irregularly distributed melanin. On the other hand, we observed that the two cell lines with the lowest dopa oxidase activity contained more mature fully melanized melanosomes than B16F10, pointing to possible alterations in the melanosome transference mechanism and lower enzymatic activity in the mature melanosomes of these two human cell lines.
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HUMAN EXPOSURE MEASUREMENTS OF AIR TOXICS
EPA's air toxics program is moving toward a risk-based focus. The framework for such a focus was laid out in the National Air Toxics Program: Integrated Urban Strategy which included the requirement for EPA to conduct a National-Scale Air Toxics Assessment (NATA) of human expos...
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Effect of chemical treatment on the acute toxicity of two commercial textile dye carriers.
Arsian-Alaton, I; Iskender, G; Ozerkan, B; Germirli Babuna, F; Okay, O
2007-01-01
In the present experimental study, the effect of chemical treatment (coagulation-flocculation) on the acute toxicity exerted by two commercial dye carriers (called Carrier A and B herein) often used in the textile industry was investigated. Two different test organisms were selected to elucidate the situations in activated sludge treatment systems (activated sludge microorganisms) as well as in receiving water bodies (ultimate marine discharge). According to the results of a comprehensive analysis covering COD removal efficiencies, sludge settling characteristics and operating costs involved in coagulation-flocculation, the optimum treatment conditions were defined as follows; application of 750 mg/L ferrous sulphate at a pH of 9.0 for Carrier A; and application of 550 mg/L ferrous sulphate at a pH of 9.0 for Carrier B. The acute toxicities of both dye carriers towards marine microalgea Phaeodactylum tricornutum could be reduced significantly after being subjected to coagulation-flocculation. Fair toxicity removals (towards heterotrophic mixed bacterial culture accommodated in activated sludge treatment) were obtained with coagulation-flocculation for both of the carriers under investigation.
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Jiang, Pingzhe; Ni, Zaizhong; Wang, Bin; Ma, Baicheng; Duan, Huikun; Li, Xiaodan; Ma, Xiaofeng; Wei, Qian; Ji, Xiangzhen; Liu, Qiqi; Xing, Shuguang; Li, Minggang
2017-04-01
A new trend has been developed using vanadium and organic ligands to form novel compounds in order to improve the beneficial actions and reduce the toxicity of vanadium compounds. In present study, vanadyl trehalose was explored the oral acute toxicity, 28 days repeated dose toxicity and genotoxicity in Kunming mice. The Median Lethal Dose (LD 50 ) of vanadyl trehalose was revealed to be 1000 mg/kg body weight in fasted Kunming mice. Stomach and intestine were demonstrated to be the main target organs of vanadyl trehalose through 28 days repeated dose toxicity study. And vanadyl trehalose also showed particular genotoxicity through mouse bone marrow micronucleus and mouse sperm malformation assay. In brief, vanadyl trehalose presented certain, but finite toxicity, which may provide experimental basis for the clinical application. Copyright © 2017 Elsevier Inc. All rights reserved.
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Li, Jin J; Tai, Hong W; Yu, Yang; Wen, Yang; Wang, Xiao H; Zhao, Yuan H
2015-07-01
Toxicity data to fish and algae were used to investigate excess toxicity between species. Results show that chemicals exhibiting excess toxicity to fish also show excess toxicity to algae for most of the compounds. This indicates that they share the same mode of action between species. Similar relationships between logKOW and toxicities to fish and algae for baseline and less inert compounds suggest that they have similar critical body residues in the two species. Differences in excess toxicity for some compounds suggest that there is a difference of physiological structure and metabolism between fish and algae. Some reactive compounds (e.g. polyamines) exhibit greater toxic effects for algae than those for fish because of relatively low bio-uptake potential of these hydrophilic compounds in fish as compared with that in algae. Esters exhibiting greater toxicity in fish than that in algae indicate that metabolism can affect the discrimination of excess toxicity from baseline level. Algae growth inhibition is a very good surrogate for fish lethality. This is not only because overall toxicity sensitivity to algae is greater than that to fish, but also the excess toxicity calculated from algal toxicity can better reflect reactivity of compounds with target molecules than fish toxicity. Copyright © 2015 Elsevier B.V. All rights reserved.
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Monitoring of human populations for early markers of cadmium toxicity: A review
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fowler, Bruce A.
2009-08-01
Exposure of human populations to cadmium (Cd) from air, food and water may produce effects in organs such as the kidneys, liver, lungs, cardiovascular, immune and reproductive systems. Since Cd has been identified as a human carcinogen, biomarkers for early detection of susceptibility to cancer are of an importance to public health. The ability to document Cd exposure and uptake of this element through biological monitoring is a first step towards understanding its health effects. Interpretation and application of biological monitoring data for predicting human health outcomes require correlation with biological measures of organ system responses to the documented exposure.more » Essential to this understanding is the detection and linkage of early biological responses toxic effects in target cell populations. Fortunately, advances in cell biology have resulted in the development of pre-clinical biological markers (biomarkers) that demonstrate measurable and characteristic molecular changes in organ systems following chemical exposures that occur prior to the onset of overt clinical disease or development of cancer. Technical advances have rendered a number of these biomarkers practical for monitoring Cd-exposed human populations. Biomarkers will be increasingly important in relation to monitoring effects from the exposure to new Cd-based high technology materials. For example, cadmium-selenium (CdSe), nano-materials made from combinations of these elements have greatly altered cellular uptake characteristics due to particle size. These differences may greatly alter effects at the target cell level and hence risks for organ toxicities from such exposures. The value of validated biomarkers for early detection of systemic Cd-induced effects in humans cannot be underestimated due to the rapid expansion of nano-material technologies. This review will attempt to briefly summarize the applications, to date, of biomarker endpoints for assessing target organ system
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Monitoring of human populations for early markers of cadmium toxicity: a review.
Fowler, Bruce A
2009-08-01
Exposure of human populations to cadmium (Cd) from air, food and water may produce effects in organs such as the kidneys, liver, lungs, cardiovascular, immune and reproductive systems. Since Cd has been identified as a human carcinogen, biomarkers for early detection of susceptibility to cancer are of an importance to public health. The ability to document Cd exposure and uptake of this element through biological monitoring is a first step towards understanding its health effects. Interpretation and application of biological monitoring data for predicting human health outcomes require correlation with biological measures of organ system responses to the documented exposure. Essential to this understanding is the detection and linkage of early biological responses toxic effects in target cell populations. Fortunately, advances in cell biology have resulted in the development of pre-clinical biological markers (biomarkers) that demonstrate measurable and characteristic molecular changes in organ systems following chemical exposures that occur prior to the onset of overt clinical disease or development of cancer. Technical advances have rendered a number of these biomarkers practical for monitoring Cd-exposed human populations. Biomarkers will be increasingly important in relation to monitoring effects from the exposure to new Cd-based high technology materials. For example, cadmium-selenium (CdSe), nano-materials made from combinations of these elements have greatly altered cellular uptake characteristics due to particle size. These differences may greatly alter effects at the target cell level and hence risks for organ toxicities from such exposures. The value of validated biomarkers for early detection of systemic Cd-induced effects in humans cannot be underestimated due to the rapid expansion of nano-material technologies. This review will attempt to briefly summarize the applications, to date, of biomarker endpoints for assessing target organ system effects in
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Lithner, Delilah; Halling, Maja; Dave, Göran
2012-05-01
Electronic waste has become one of the fastest growing waste problems in the world. It contains both toxic metals and toxic organics. The aim of this study was to (1) investigate to what extent toxicants can leach from different electronic products, components, and materials into water and (2) identify which group of toxicants (metals or hydrophobic organics) that is causing toxicity. Components from five discarded electronic products (cell phone, computer, phone modem, keyboard, and computer mouse) were leached in deionised water for 3 days at 23°C in concentrations of 25 g/l for metal components, 50 g/l for mixed-material components, and 100 g/l for plastic components. The water phase was tested for acute toxicity to Daphnia magna. Eighteen of 68 leachates showed toxicity (with immobility of D. magna ≥ 50% after 48 h) and came from metal or mixed-material components. The 8 most toxic leachates, with 48 h EC(50)s ranging from 0.4 to 20 g/l, came from 2 circuit sheets (key board), integrated drive electronics (IDE) cable clips (computer), metal studs (computer), a circuit board (computer mouse), a cord (phone modem), mixed parts (cell phone), and a circuit board (key board). All 5 electronic products were represented among them. Toxicity identification evaluations (with C18 and CM resins filtrations and ethylenediaminetetraacetic acid addition) indicated that metals caused the toxicity in the majority of the most toxic leachates. Overall, this study has shown that electronic waste can leach toxic compounds also during short-term leaching with pure water.
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Mackay, Donald; Celsie, Alena K D; Parnis, J Mark; McCarty, Lynn S; Arnot, Jon A; Powell, David E
2017-05-01
A 1-compartment toxicokinetic model is used to characterize the chemical exposure toxicity space (CETS), providing a novel graphic tool that can aid in the design of aquatic toxicity tests for fish and for interpreting their results. The graph depicts the solution to the differential equation describing the uptake kinetics of a chemical by a modeled fish under conventional bioassay conditions. The model relates the exposure concentration in the water to a dimensionless time and the onset of toxicity as determined by an estimated or assumed critical body residue or incipient lethal aqueous concentration. These concentration graphs are specific to each chemical and exposure and organism parameters and clearly demonstrate differences in toxicity between chemicals and how factors such as hydrophobicity influence the toxic endpoint. The CETS plots can also be used to assess bioconcentration test conditions to ensure that concentrations are well below toxic levels. Illustrative applications are presented using a recent set of high-quality toxicity data. Conversion of concentrations to chemical activities in the plots enables results for different baseline toxicants to be superimposed. For chemicals that have different modes of toxic action, the increased toxicity then becomes apparent. Implications for design and interpretation of aquatic toxicity tests are discussed. The model, and pictorial visualization of the time-course of aquatic toxicity tests, may contribute to improvements in test design, implementation, and interpretation, and to reduced animal usage. Environ Toxicol Chem 2017;36:1389-1396. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.
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Cerbo, Atlas Adonis V; Ballesteros, Florencio; Chen, Teng Chien; Lu, Ming-Chun
2017-01-01
Solidification and stabilization are well-known technologies used for treating hazardous waste. These technologies that use cementitious binder have been applied for decades as a final treatment procedure prior to the hazardous waste disposal. In the present work, hazardous waste like fly ash containing high concentrations of heavy metals such Zn (4715.56 mg/kg), Pb (1300.56 mg/kg), and Cu (534.72 mg/kg) and amounts of Ag, Cd, Co, Cr, Mn, and Ni was sampled from a city refuse incinerator facility. This fly ash was utilized in the solidification/stabilization of heavy metal sludge since fly ash has cement-like characteristics. Cement additives such as sodium sulfate, sodium carbonate, and ethylenediaminetetraacetic acid (EDTA) was incorporated to the solidified matrix in order to determine its effect on the solidification/stabilization performance. The solidified matrix was cured for 7, 14, 21, and 28 days prior for its physical and chemical characterizations. The results show that the solidified matrix containing 40% fly ash and 60% cement with heavy metal sludge was the formulation that has the highest fly ash content with a satisfactory strength. The solidified matrix was also able to immobilize the heavy metals both found in the fly ash and sludge based on the toxicity characteristic leaching procedure (TCLP) test. It also shows that the incorporation of sodium carbonate into the solidified matrix not only further improved the compressive strength from 0.36 MPa (without Na 2 CO 3 ) to 0.54 MPa (with Na 2 CO 3 ) but also increased its leaching resistance.
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Zaaboub, Noureddine; Martins, Maria Virgínia Alves; Dhib, Amel; Béjaoui, Béchir; Galgani, François; El Bour, Monia; Aleya, Lotfi
2015-12-01
The authors investigated sediment quality in Bizerte Lagoon (Tunisia) focusing on geochemical characteristics, metal sediment fractionation and elutriate toxicity assessment. Nickel, Cu, Zn, Pb, Cr and Cd partitioning in sediments was studied; accumulation and bioavailability were elucidated using enrichment factors, sequential extractions, redox potential, acid volatile sulfide and biotest procedures in toxicity evaluation. Results revealed an accumulation for Pb and Zn, reaching 99 and 460 mg kg(-1) respectively. In addition, the acid volatile sulfide values were high in both eastern and western lagoon areas, thus affecting metal availability. Mean enrichment factor values for Pb and Zn were 4.8 and 4.9, respectively, with these elements as the main contributors to the lagoon's moderate enrichment level. Toxicity levels were influenced by accumulation of Zn in different surface sediment areas. Core sediments were investigated in areas with the highest metal concentrations; metal fractionation and biotest confirmed that Zn contributes to sediment toxicity. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Discriminating modes of toxic action in mice using toxicity in BALB/c mouse fibroblast (3T3) cells.
Huang, Tao; Yan, Lichen; Zheng, Shanshan; Wang, Yue; Wang, Xiaohong; Fan, Lingyun; Li, Chao; Zhao, Yuanhui; Martyniuk, Christopher J
2017-12-01
The objective of this study was to determine whether toxicity in mouse fibroblast cells (3T3 cells) could predict toxicity in mice. Synthesized data on toxicity was subjected to regression analysis and it was observed that relationship of toxicities between mice and 3T3 cells was not strong (R 2 = 0.41). Inclusion of molecular descriptors (e.g. ionization, pKa) improved the regression to R 2 = 0.56, indicating that this relationship is influenced by kinetic processes of chemicals or specific toxic mechanisms associated to the compounds. However, to determine if we were able to discriminate modes of action (MOAs) in mice using the toxicities generated from 3T3 cells, compounds were first classified into "baseline" and "reactive" guided by the toxic ratio (TR) for each compound in mice. Sequence, binomial and recursive partitioning analyses provided strong predictions of MOAs in mice based upon toxicities in 3T3 cells. The correct classification of MOAs based on these methods was 86%. Nearly all the baseline compounds predicted from toxicities in 3T3 cells were identified as baseline compounds from the TR in mice. The incorrect assignment of MOAs for some compounds is hypothesized to be due to experimental uncertainty that exists in toxicity assays for both mice and 3T3 cells. Conversely, lack of assignment can also arise because some reactive compounds have MOAs that are different in mice compared to 3T3 cells. The methods developed here are novel and contribute to efforts to reduce animal numbers in toxicity tests that are used to evaluate risks associated with organic pollutants in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Yim, Jin Hee; Kim, Kyoung W; Kim, Sang D
2006-11-02
In this study, the effect of hardness on the combined outcome of metal mixtures was investigated using Daphnia magna. The toxic unit (TU) was calculated using modified LC(50) values based on the hardness (i.e., LC(50-soft) and LC(50-hard)). From a bioassay test, the degree of sensitivity to hardness on the toxicity changes was in the order: Cd
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Balmuri, Sricharani Rao
Cadmium (Cd), classified as human carcinogen, is an extremely toxic heavy metal pollutant, and there is an increasing environmental concern for cadmium exposure through anthropogenic sources including cigarette smoke. Though Cd based nanoparticles such as cadmium oxide (CdO) are being widely used in a variety of clinical and industrial applications, the toxicity of CdO nanoparticles has not been well characterized. Herein we report the toxicity of CdO nanoparticles employing zebrafish as a model. Two different CdO nanoparticles were prepared, calcination of Cd(OH){sub 2} without any organic molecule (CdO-1) and calcination of Cd-citrate coordination polymer (CdO-2), to evaluate and compare themore » toxicity of these two different CdO nanoparticles. Results show that zebrafish exposed to CdO-2 nanoparticles expressed reduced toxicity as judged by lower oxidative stress levels, rescue of liver carboxylesterases and reduction in metallothionein activity compared to CdO-1 nanoparticles. Histopathological observations also support our contention that CdO-1 nanoparticles showed higher toxicity relative to CdO-2 nanoparticles. The organic unit of Cd-citrate coordination polymer might have converted into carbon during calcination that might have covered the surface of CdO nanoparticles. This carbon surface coverage can control the release of Cd{sup 2+} ions in CdO-2 compared to non-covered CdO-1 nanoparticles and hence mitigate the toxicity in the case of CdO-2. This was supported by atomic absorption spectrophotometer analyses of Cd{sup 2+} ions release from CdO-1 and CdO-2 nanoparticles. Thus the present study clearly demonstrates the toxicity of CdO nanoparticles in an aquatic animal and also indicates that the toxicity could be substantially reduced by carbon coverage. This could have important implications in terms of anthropogenic release and environmental pollution caused by Cd and human exposure to Cd{sup 2+} from sources such as cigarette smoke. - Highlights:
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Burkholder, J M; Glasgow, H B; Deamer-Melia, N J; Springer, J; Parrow, M W; Zhang, C; Cancellieri, P J
2001-01-01
We describe the two species of the toxic Pfiesteria complex to date (Pfiesteria piscicida and Pfiesteria shumwayae), their complex life cycles, and the characteristics required for inclusion within this complex. These species resemble P. piscicida Steidinger & Burkholder and also have a) strong attraction to fresh fish tissues and excreta, b) toxic activity stimulated by live fish, and c) production of toxin that can cause fish death and disease. Amoeboid stages were verified in 1992-1997 by our laboratory (various stages from toxic cultures) and that of K. Steidinger and co-workers (filose amoebae in nontoxic cultures), and in 2000 by H. Marshall and co-workers (various stages from toxic cultures), from clonal Pfiesteria spp. cultures, using species-specific polymerase chain reaction-based molecular probes with cross-confirmation by an independent specialist. Data were provided from tests of the hypothesis that Pfiesteriastrains differ in response to fresh fish mucus and excreta, algal prey, and inorganic nutrient (N, P) enrichment, depending on functional type or toxicity status. There are three functional types: TOX-A, in actively toxic, fish-killing mode; TOX-B, temporarily nontoxic, without access to live fish for days to weeks, but capable of toxic activity if fish are added; and NON-IND, noninducible with negligible toxicity in the presence of live fish. NON-IND Pfiesteria attained highest zoospore production on algal prey without or without inorganic nitrogen or inorganic phosphorus enrichment. TOX-B Pfiesteria was intermediate and TOX-A was lowest in zoospore production on algal prey with or without nutrients. TOX-A Pfiesteria spp. showed strong behavioral attraction to fresh fish mucus and excreta in short-term trials, with intermediate attraction of TOX-B zoospores and relatively low attraction of NON-IND cultures when normalized for cell density. The data for these clones indicated a potentially common predatory behavioral response, although differing
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Zebrafish developmental toxicity testing is an emerging field, which faces considerable challenges regarding data meta-analysis and the establishment of standardized test protocols. Here, we present an initial correlation study on toxicity of 133 chemicals based on data in the li...
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Application of the Hard and Soft, Acids and Bases (HSAB) theory to toxicant--target interactions.
Lopachin, Richard M; Gavin, Terrence; Decaprio, Anthony; Barber, David S
2012-02-20
Many chemical toxicants and/or their active metabolites are electrophiles that cause cell injury by forming covalent bonds with nucleophilic targets on biological macromolecules. Covalent reactions between nucleophilic and electrophilic reagents are, however, discriminatory since there is a significant degree of selectivity associated with these interactions. Over the course of the past few decades, the theory of Hard and Soft, Acids and Bases (HSAB) has proven to be a useful tool in predicting the outcome of such reactions. This concept utilizes the inherent electronic characteristic of polarizability to define, for example, reacting electrophiles and nucleophiles as either hard or soft. These HSAB definitions have been successfully applied to chemical-induced toxicity in biological systems. Thus, according to this principle, a toxic electrophile reacts preferentially with biological targets of similar hardness or softness. The soft/hard classification of a xenobiotic electrophile has obvious utility in discerning plausible biological targets and molecular mechanisms of toxicity. The purpose of this perspective is to discuss the HSAB theory of electrophiles and nucleophiles within a toxicological framework. In principle, covalent bond formation can be described by using the properties of their outermost or frontier orbitals. Because these orbital energies for most chemicals can be calculated using quantum mechanical models, it is possible to quantify the relative softness (σ) or hardness (η) of electrophiles or nucleophiles and to subsequently convert this information into useful indices of reactivity. This atomic level information can provide insight into the design of corroborative laboratory research and thereby help investigators discern corresponding molecular sites and mechanisms of toxicant action. The use of HSAB parameters has also been instrumental in the development and identification of potential nucleophilic cytoprotectants that can scavenge toxic
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APPLICATION OF THE HARD AND SOFT, ACIDS AND BASES (HSAB) THEORY TO TOXICANT-TARGET INTERACTIONS
LoPachin, Richard M.; Gavin, Terrence; DeCaprio, Anthony; Barber, David S.
2011-01-01
Many chemical toxicants and/or their active metabolites are electrophiles that cause cell injury by forming covalent bonds with nucleophilic targets on biological macromolecules. Covalent reactions between nucleophilic and electrophilic reagents are however discriminatory, since there is a significant degree of selectivity associated with these interactions. Over the course of the past few decades, the theory of Hard and Soft, Acid and Bases (HSAB) has proven to be a useful tool in predicting the outcome of such reactions. This concept utilizes the inherent electronic characteristic of polarizability to define, for example, reacting electrophiles and nucleophiles as either hard or soft. These HSAB definitions have been successfully applied to chemical-induced toxicity in biological systems. Thus, according to this principle, a toxic electrophile reacts preferentially with biological targets of similar hardness or softness. The soft/hard classification of a xenobiotic electrophile has obvious utility in discerning plausible biological targets and molecular mechanisms of toxicity. The purpose of this Perspective is to discuss the HSAB theory of electrophiles and nucleophiles within a toxicological framework. In principle, covalent bond formation can be described by using the properties of their outermost or frontier orbitals. Because these orbital energies for most chemicals can be calculated using quantum mechanical models, it is possible to quantify the relative softness (σ) or hardness (η) of electrophiles or nucleophiles and to subsequently convert this information into useful indices of reactivity. This atomic level information can provide insight into the design of corroborative laboratory research and thereby help investigators discern corresponding molecular sites and mechanisms of toxicant action. The use of HSAB parameters has also been instrumental in the development and identification of potential nucleophilic cytoprotectants that can scavenge toxic
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Na, Young Eun; Kim, Soon-Il; Bang, Hea-Son; Kim, Byung-Seok; Ahn, Young-Joon
2011-06-10
The toxicity of two cassia oils, four cinnamon oils and (E)-cinnamaldehyde and (E)-cinnamic acid and 34 structurally related compounds to adult Dermanyssus gallinae (De Geer) collected from a poultry house was examined using a vapour-phase mortality bioassay. Results were compared with those of dichlorvos, a conventional acaricide. The cassia and cinnamon oils (cinnamon technical, cinnamon #500, cassia especial, cassia true, cinnamon bark and cinnamon green leaf) exhibited good fumigant toxicity (LD(50), 11.79-26.40 μg cm(-3)). α-Methyl-(E)-cinnamaldehyde (LD(50), 0.45 μg cm(-3)) and (E)-cinnamaldehyde (0.54 μg cm(-3)) were the most toxic compounds and the toxicity of these compounds was comparable to that of dichlorvos (0.30 μg cm(-3)). Potent fumigant toxicity was also observed in allyl cinnamate, ethyl-α-cyanocinnamate, (E)-2-methoxylcinnamic acid and (Z)-2-methoxylcinnamic acid (LD(50), 0.81-0.92 μg cm(-3)). Structure-activity relationships indicate that structural characteristics, such as types of functional groups and carbon skeleton rather than vapour pressure parameter, appear to play a role in determining toxicity. The essential oils and compounds described merit further study as potential acaricides for the control of D. gallinae populations as fumigants with contact action due to global efforts to reduce the level of highly toxic synthetic acaricides in the agricultural environment. Copyright © 2011. Published by Elsevier B.V.
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Tracey, J A; Cassidy, N; Casey, P B; Ali, I
2002-01-01
Bupropion is a monocyclic antidepressant structurally related to amphetamine. Zyban, a sustained-release formulation of bupropion hydrochloride, was recently released in Ireland, as a smoking cessation aid. In the initial 6 months since it's introduction, 12 overdose cases have been reported to The National Poisons Information Centre. 8 patients developed symptoms of toxicity. Common features included tachycardia, drowsiness, hallucinations and convulsions. Two patients developed severe cardiac arrhythmias, including one patient who was resuscitated following a cardiac arrest. All patients recovered without sequelae. We report a case of a 31 year old female who required admission to the Intensive Care Unit for ventilation and full supportive therapy, following ingestion of 13.5g bupropion. Recurrent seizures were treated with diazepam and broad complex tachycardia was successfully treated with adenosine. Zyban caused significant neurological and cardiovascular toxicity in overdose. The potential toxic effects should be considered when prescribing it as a smoking cessation aid.
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Tier 3 Toxicity Value White Paper
The purpose of this white paper is to articulate the issues pertaining to Tier 3 toxicity values and provide recommendations on processes that will improve the transparency and consistency of identifying, evaluating, selecting, and documenting Tier 3 toxicity values for use in the Superfund and Resource Conservation and Recovery Act (RCRA) programs. This white paper will be used to assist regional risk assessors in selecting Tier 3 toxicity values as well as provide the foundation for future regional and national efforts to improve guidance and policy on Tier 3 toxicity values.
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A toxicity identification evaluation (TIE) was conducted on effluent from a major industrial discharger. Initial monitoring showed slight chronic toxicity to Ceriodaphnia dubia; later sample showed substantial toxicity to C. dubia. Chemical analysis detected hexavalent chromium ...
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Predicting the toxicity of metal mixtures
Balistrieri, Laurie S.; Mebane, Christopher A.
2013-01-01
The toxicity of single and multiple metal (Cd, Cu, Pb, and Zn) solutions to trout is predicted using an approach that combines calculations of: (1) solution speciation; (2) competition and accumulation of cations (H, Ca, Mg, Na, Cd, Cu, Pb, and Zn) on low abundance, high affinity and high abundance, low affinity biotic ligand sites; (3) a toxicity function that accounts for accumulation and potency of individual toxicants; and (4) biological response. The approach is evaluated by examining water composition from single metal toxicity tests of trout at 50% mortality, results of theoretical calculations of metal accumulation on fish gills and associated mortality for single, binary, ternary, and quaternary metal solutions, and predictions for a field site impacted by acid rock drainage. These evaluations indicate that toxicity of metal mixtures depends on the relative affinity and potency of toxicants for a given aquatic organism, suites of metals in the mixture, dissolved metal concentrations and ratios, and background solution composition (temperature, pH, and concentrations of major ions and dissolved organic carbon). A composite function that incorporates solution composition, affinity and competition of cations for two types of biotic ligand sites, and potencies of hydrogen and individual metals is proposed as a tool to evaluate potential toxicity of environmental solutions to trout.
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Toxicity of herbicides in highway runoff.
Huang, Xinjiang; Fong, Stephanie; Deanovic, Linda; Young, Thomas M
2005-09-01
Previous field monitoring at two highway sites found highway-applied herbicides in storm water runoff at maximum concentrations ranging from 10 microg/L for glyphosate and diuron to as high as 200 microg/L for oryzalin. To determine whether these herbicides at these concentrations can cause any toxicity to aquatic organisms, a standard toxicity study was conducted. Storm water was collected along Highway 37, Sonoma County, California, USA, and the herbicides isoxaben, oryzalin, diuron, clopyralid, and glyphosate were spiked into the storm water at the highest concentrations observed during the five previous field-monitoring campaigns. Three different toxicity studies were conducted and the results showed the following: No significant reduction in reproduction or increase in mortality relative to the control for an 8-d Ceriodaphnia (water flea) toxicity test; no significant increase in mortality or decrease in biomass compared to the control during a 7-d Pimephales (fish) toxicity test; and, in a 96-h Selenastrum (algae) toxicity test, both the 10-microg/L diuron treatment and the combined 50-microg/L isoxaben plus 200-microg/L oryzalin treatment produced significant (p < 0.05) reductions in algal growth compared to the controls, although the 30-microg/L clopyralid or 10-microg/L glyphosate treatments did not exhibit any toxic effects.
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Kleinstreuer, Clement; Feng, Yu
2013-01-01
Inhaled toxic aerosols of conventional cigarette smoke may impact not only the health of smokers, but also those exposed to second-stream smoke, especially children. Thus, less harmful cigarettes (LHCs), also called potential reduced exposure products (PREPs), or modified risk tobacco products (MRTP) have been designed by tobacco manufacturers to focus on the reduction of the concentration of carcinogenic components and toxicants in tobacco. However, some studies have pointed out that the new cigarette products may be actually more harmful than the conventional ones due to variations in puffing or post-puffing behavior, different physical and chemical characteristics of inhaled toxic aerosols, and longer exposure conditions. In order to understand the toxicological impact of tobacco smoke, it is essential for scientists, engineers and manufacturers to develop experiments, clinical investigations, and predictive numerical models for tracking the intake and deposition of toxicants of both LHCs and conventional cigarettes. Furthermore, to link inhaled toxicants to lung and other diseases, it is necessary to determine the physical mechanisms and parameters that have significant impacts on droplet/vapor transport and deposition. Complex mechanisms include droplet coagulation, hygroscopic growth, condensation and evaporation, vapor formation and changes in composition. Of interest are also different puffing behavior, smoke inlet conditions, subject geometries, and mass transfer of deposited material into systemic regions. This review article is intended to serve as an overview of contributions mainly published between 2009 and 2013, focusing on the potential health risks of toxicants in cigarette smoke, progress made in different approaches of impact analyses for inhaled toxic aerosols, as well as challenges and future directions. PMID:24065038
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Tonacchera, M; Chiovato, L; Pinchera, A; Agretti, P; Fiore, E; Cetani, F; Rocchi, R; Viacava, P; Miccoli, P; Vitti, P
1998-02-01
Toxic multinodular goiter is a cause of nonautoimmune hyperthyroidism and is believed to differ in its nature and pathogenesis from toxic adenoma. Gain-of-function mutations of the TSH receptor gene have been identified as a cause of toxic adenoma. The pathogenesis at the molecular level of hyperfunctioning nodules in toxic multinodular goiter has yet not been reported. Six patients with a single hot nodule within a multinodular goiter and 11 patients with toxic thyroid adenoma were enrolled in our study. At histology five hyperfunctioning nodules in multinodular goiters showed the features of adenomas, and one was identified as a hyperplastic nodule. The entire exon 10 of the TSH receptor gene was directly sequenced after PCR amplification from genomic DNA obtained from surgical specimens. Functional studies of mutated receptors were performed in COS-7 cells. Five out of 6 (83%) hyperfunctioning nodules within toxic multinodular goiters harbored a TSH receptor mutation. A TSH receptor mutation was also evident in the hyperfunctioning nodule that at histology had the features of noncapsulated hyperplastic nodule. Among toxic adenomas, 8 out of 11 (72%) nodules harbored a TSH receptor mutation. All the mutations were heterozygotic and somatic. Nonfunctioning nodules, whether adenomas or hyperplastic nodules present in association with hyperfunctioning nodules in the same multinodular goiters, had no TSH receptor mutation. All the mutations identified had constitutive activity as assessed by cAMP production after expression in COS-7 cells. Hyperfunctioning thyroid nodules in multinodular goiters recognize the same pathogenetic event (TSH receptor mutation) as toxic adenoma. Other mechanisms are implicated in the growth of nonfunctioning thyroid nodules coexistent in the same gland.
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Fluoroacetate-mediated toxicity of fluorinated ethanes.
Keller, D A; Roe, D C; Lieder, P H
1996-04-01
A series of 1-(di)halo-2-fluoroethanes reported in the literature to be nontoxic or of low toxicity were found to be highly toxic by the inhalation route. Experiments were performed that showed the compounds, 1,2-difluoroethane, 1-chloro-2-fluoroethane, 1-chloro-1,2-difluoroethane, and 1-bromo-2-fluoroethane to be highly toxic to rats upon inhalation for 4 hr. All four compounds had 4-hr approximate lethal concentrations of < or = 100 ppm in rats. In contrast, 1,1-difluoroethane (commonly referred to as HFC-152a) has very low acute toxicity with a 4-hr LC50 of > 400,000 ppm in rats. Rats exposed to the selected toxic fluoroethanes showed clinical signs of fluoroacetate toxicity (lethargy, hunched posture, convulsions). 1,2-Difluoroethane, 1-chloro-2-fluoroethane, 1-chloro-1,2-difluoroethane, and 1-bromo-2-fluoroethane were shown to increase concentrations of citrate in serum and heart tissue, a hallmark of fluoroacetate intoxication. 19F NMR analysis confirmed that fluoroacetate was present in the urine of rats exposed to each toxic compound. Fluorocitrate, a condensation product of fluoroacetate and oxaloacetate, was identified in the kidney of rats exposed to 1,2-difluoroethane. There was a concentration-related elevation of serum and heart citrate in rats exposed to 0-1000 ppm 1,2-fluoroethane. Serum citrate was increased up to 5-fold and heart citrate was increased up to 11-fold over control citrate levels. Metabolism of 1,2-difluoroethane by cytochrome P450 (most likely CYP2E1) is suspected because pretreatment of rats or mice with SKF-525F, disulfiram, or dimethyl sulfoxide prevented or delayed the toxicity observed in rats not pretreated. Experimental evidence indicates that the metabolism of the toxic fluoroethanes is initiated at the carbon-hydrogen bond, with metabolism to fluoroacetate via an aldehyde or an acyl fluoride. The results of these studies show that 1-(di)halo-2-fluoroethanes are highly toxic to rats and should be considered a hazard to humans
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Classification of Chemicals Based On Structured Toxicity ...
Thirty years and millions of dollars worth of pesticide registration toxicity studies, historically stored as hardcopy and scanned documents, have been digitized into highly standardized and structured toxicity data within the Toxicity Reference Database (ToxRefDB). Toxicity-based classifications of chemicals were performed as a model application of ToxRefDB. These endpoints will ultimately provide the anchoring toxicity information for the development of predictive models and biological signatures utilizing in vitro assay data. Utilizing query and structured data mining approaches, toxicity profiles were uniformly generated for greater than 300 chemicals. Based on observation rate, species concordance and regulatory relevance, individual and aggregated effects have been selected to classify the chemicals providing a set of predictable endpoints. ToxRefDB exhibits the utility of transforming unstructured toxicity data into structured data and, furthermore, into computable outputs, and serves as a model for applying such data to address modern toxicological problems.
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Toxic hazards in aerial application.
DOT National Transportation Integrated Search
1962-04-01
An analysis of the hazards accompanying the aerial application of toxic pest-control chemicals are presented. The nature of teh chemicals, teh symptoms of toxicity, recommended treatment, and suggestions for safe-handling, are discussed
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Hale, Beverley; Gopalapillai, Yamini; Pellegrino, Amanda; Jennett, Tyson; Kikkert, Julie; Lau, Wilson; Schlekat, Christian; McLaughlin, Mike J
2017-12-01
The Existing Substances Regulation Risk Assessments by the European Union (EU RA) generated new toxicity data for soil organisms exposed to Ni added to sixteen field-collected soils with low background concentration of metals and varying physico-chemical soil characteristics. Using only effective cation exchange capacity (eCEC) as a bioavailability correction, chronic toxicity of Ni in soils with a wide range of characteristics could be predicted within a factor of two. The objective of the present study was to determine whether this was also the case for three independent data sets of Ni toxicity thresholds. Two of the data sets were from Community Based Risk Assessments in Port Colborne ON, and Sudbury ON (Canada) for soils containing elevated concentrations of Ni, Co and Cu arising from many decades of Ni mining, smelting and refining. The third data set was the Metals in Asia study of soluble Ni added to field soils in China. These data yielded 72 leached and aged EC 10 /NOEC values for soil Ni, for arthropods, higher plants and woodlot structure and function. These were reduced to nine most sensitive single or geometric mean species/function endpoints, none of which were lower than the HC 5 predicted for a soil with an eCEC of 20 cmol/kg. Most of these leached and aged EC 10 /NOEC values were from soils co-contaminated with Cu, in some cases at its median HC 5 as predicted by the EU RA from soil characteristics. We conclude that the EU RA is protective of Ni toxicity to higher-tier ecological endpoints, including in mixture with Cu, before the assessment factor of 2 is applied. We suggest that for prospective risk assessment, the bioavailability based PNEC (HC 5 /2) be used as a conservative screen, but for retrospective and site-specific risk assessment, the bioavailability based HC 5 is sufficient. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Reeve, Peter J; Fallowfield, Howard J
2018-01-01
The objective of this review is to highlight the need for further investigation of microbial toxicity caused by desorption of surfactant from Surfactant Modified Zeolite (SMZ). SMZ is a low cost, versatile permeable reactive media which has the potential to treat multiple classes of contaminants. With this combination of characteristics, SMZ has significant potential to enhance water and wastewater treatment processes. Surfactant desorption has been identified as a potential issue for the ongoing usability of SMZ. Few studies have investigated the toxicity of surfactants used in zeolite modification towards microorganisms and fewer have drawn linkages between surfactant desorption and surfactant toxicity. This review provides an overview of natural zeolite chemistry, characteristics and practical applications. The chemistry of commonly used surfactants is outlined, along with the kinetics that drive their adsorption to the zeolite surface. Methodologies to characterise this surfactant loading are also described. Applications of SMZ in water remediation are highlighted, giving focus to applications which deal with biological pollutants and where microorganisms play a role in the remediation process. Studies that have identified surfactant desorption from SMZ are outlined. Finally, the toxicity of a commonly used cationic surfactant towards microorganisms is discussed. This review highlights the potential for surfactant to desorb from the zeolite surface and the need for further research into the toxicity of this desorbed surfactant towards microorganisms, including pathogens and environmental microbes. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Animal Toxicity of Phytopathogenic Fungi
Main, C. E.; Hamilton, P. B.
1972-01-01
Twelve genera of phytopathogenic fungi comprising 27 species previously reported to produce phytotoxins were tested concurrently for animal and plant toxicity. There appeared to be no direct relationship between plant and animal toxicity. PMID:5059620
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Huang, Ze-Chun; Chen, Tong-Bin; Lei, Mei; Liu, Ying-Ru; Hu, Tian-Dou
2008-07-15
The arsenic (As) hyperaccumulators, Pteris vittata and Pteris cretica and an As-tolerant plant Boehmeria nivea, were selected to compare the toxicity, uptake, and transportation of inorganic arsenate (As(V)) and its methylated counterpart dimethylarsinic acid (DMA). The XANES method was used to elucidate the effect of As species transformation on As toxicity and accumulation characteristics. Significantly higher toxicity and lower accumulation of DMAthan inorganic As(V) was shown in the As hyperaccumulators and the As-tolerant plant. Reduction of As(V) was commonly found in the plants. Arsenic complexation with thiols, which have less mobility in plants and usually occur in As-tolerant plants, was also found in rhizoids of P. cretica. Plants with greater ability to form As-thiolate have lower ability for upward transport of As. Demethylation of DMA occurred in the three plants. The DMA component decreased from the rhizoids to the fronds in both hyperaccumulators, while this tendency is reverse in B. nivea.
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Madadi, Parvaz; Hildebrandt, Doris; Lauwers, Albert E.; Koren, Gideon
2013-01-01
Background The impact of the prescription opioid public health crisis has been illustrated by the dramatic increase in opioid-related deaths in North America. We aimed to identify patterns and characteristics amongst opioid-users whose cause of death was related to opioid toxicity. Methods This was a population-based study of Ontarians between the years 2006 and 2008. All drug-related deaths which occurred during this time frame were reviewed at the Office of the Chief Coroner of Ontario, and opioid-related deaths were identified. Medical, toxicology, pathology, and police reports were comprehensively reviewed. Narratives, semi-quantitative, and quantitative variables were extracted, tabulated, and analyzed. Results Out of 2330 drug-related deaths in Ontario, 58% were attributed either in whole or in part, to opioids (n = 1359). Oxycodone was involved in approximately one-third of all opioid-related deaths. At least 7% of the entire cohort used opioids that were prescribed for friends and/or family, 19% inappropriately self-administered opioids (injection, inhalation, chewed patch), 3% were recently released from jail, and 5% had been switched from one opioid to another near the time of death. Accidental deaths were significantly associated with personal history of substance abuse, enrollment in methadone maintenance programs, cirrhosis, hepatitis, and cocaine use. Suicides were significantly associated with mental illness, previous suicide attempts, chronic pain, and a history of cancer. Significance/Conclusion These results identify novel, susceptible groups of opioid-users whose cause of death was related to opioids in Ontario and provide the first evidence to assist in quantifying the contribution of opioid misuse and diversion amongst opioid-related mortality in Canada. Multifaceted prevention strategies need to be developed based on subpopulations of opioid users. PMID:23577131
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Toxicity of carbon nanotubes: A review.
Francis, Arul Prakash; Devasena, Thiyagarajan
2018-03-01
Carbon nanotubes (CNTs) are widely used in the aerospace, automotive, and electronics industries because of their stability, enhanced metallic, and electrical properties. CNTs are also being investigated for biomedical applications such as drug delivery systems and biosensors. However, the toxic potential of CNTs was reported in various cell lines and animal models. The toxicity depends on diverse properties of the CNTs, such as length, aspect ratio, surface area, degree of aggregation, purity, concentration, and dose. In addition, CNTs and/or associated contaminants were well known for oxidative stress, inflammation, apoptosis, pulmonary inflammation, fibrosis, and granuloma in lungs. The increased production of CNTs likely enhanced the possibility of its exposure in people. Studies on the toxicity of CNTs are mainly focused on the pulmonary effects after intratracheal administration, and only a few studies are reported about the toxicity of CNTs via other routes of exposure. So, it is essential to consider the chronic toxicity of CNTs before using them for various biomedical applications. This review focuses on the potential toxicities of CNTs.
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Evaluation of Functional SiO₂ Nanoparticles Toxicity by a 3D Culture Model.
Pellen-Mussi, Pascal; Tricot-Doleux, Sylvie; Neaime, Chrystelle; Nerambourg, Nicolas; Cabello-Hurtado, Francisco; Cordier, Stéphane; Grasset, Fabien; Jeanne, Sylvie
2018-05-01
as a kind of non-metal oxide SiO2 NPs have been extensively used in biomedicine, pharmaceuticals and other industrial manufacturing fields, such as DNA delivery, cancer therapy… Our group had developed a method based on microemulsion process to prepare SiO2 NPs incorporating photonic or magnetic nanocrystals and luminescent nanosized inorganic metal atom clusters. However, the toxicity of nanoparticles is known to be closely related to their physico-chemical characteristics and chemical composition. it is therefore of interest to investigate the toxicity of these novel SiO2 NPs to the cells that may come in contact. the potential toxic effect of the functional @SiO2 NPs containing Mo6 clusters with or without gold nanoparticles was investigated, at concentrations 1 μg/mL, 10 μg/mL and 100 μg/mL each, on three different cell lines. Cell viability was measured by the MTT test in monolayer's culture whereas the cytotoxicity in spheroid model was examined by the APH assay. In a second time, oxidative-stress-induced cytotoxicity was investigated through glutathione levels dosages. the results indicated that both A549 and L929 cell lines did not exhibit susceptibility to functional @SiO2 NPs-induced oxidative stress unlike KB cells. SiO2 NPs containing CMB may become toxic to cultured cells but only at a very high dosage level. Therefore, this toxicity depends on cell lines and more, on the model of cell cultures. The selection of appropriate cell line remains a critical component in nanotoxicology. these results are relevant to future applications of SiO2 gold-cluster NPs in controlled release applications.
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National Air Toxics Assessment (NATA)
NATA provides estimates of the risk of cancer and other serious health effects from inhaling air toxics in order to inform both national and more localized efforts to identify and prioritize air toxics, emission source types.
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Endocrine abnormalities in lithium toxicity.
Shanks, Gabriella; Mishra, Vinita; Nikolova, Stanka
2017-10-01
Lithium toxicity can manifest as a variety of biochemical -abnormalities. This case report describes a patient -presenting to the emergency department with neuropsychiatric -symptoms on a background of bipolar disorder, for which she was prescribed lithium for 26 years previously. Cases of lithium toxicity are rare but can be severe and this case report -demonstrates to clinicians that they must be thorough in investigating patients with lithium toxicity, as there are many potential abnormalities that can manifest concurrently. © Royal College of Physicians 2017. All rights reserved.
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Vitamin E modulates reproductive toxicity of pyrethroid lambda-cyhalothrin in male rabbits.
Yousef, Mokhtar I
2010-05-01
The objective of the current study was to analyze the reproductive toxicity caused by lambda-cyhalothrin (LCT) in male rabbits, and to evaluate the possible protective effect of vitamin E (Vit. E) as antioxidant. Animals were orally administered their respective doses of LCT every other day and given drinking water supplemented with vitamin E for 16 weeks. Results showed that semen quality was deteriorated following treatment with LCT. Also, testosterone levels, body weight (BW), feed intake (FI), and relative testes (RTW) and epididymis (REW) weights were significantly decreased. Concentrations of thiobarbituric acid-reactive substances (TBARS) were significantly increased in seminal plasma of rabbits treated with LCT compared with control. While, activities of glutathione S-transferase (GST), transaminases and acid phosphatase (AcP) were significantly decreased. Vitamin E alone significantly increased testosterone levels, BW, FI, RTW, REW, semen characteristics and seminal plasma enzymes, and decreased the levels of TBARS. Also, the present study showed that vitamin E might be effective against LCT-induced reproductive toxicity. It was suggested that LCT exerted a significant adverse effect on reproductive performance of male rabbits. Furthermore, vitamin E antagonized the toxic effects of LCT and improved semen quality of male rabbit. Copyright (c) 2010 Elsevier Ltd. All rights reserved.
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National Air Toxic Assessments (NATA) Results
The National Air Toxics Assessment was conducted by EPA in 2002 to assess air toxics emissions in order to identify and prioritize air toxics, emission source types and locations which are of greatest potential concern in terms of contributing to population risk. This data source provides downloadable information on emissions at the state, county and census tract level.
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Mahoney, Sharlee; Najera, Michelle; Bai, Qing; Burton, Edward A.; Veser, Götz
2016-01-01
Complex engineered nanomaterials (CENs) are a rapidly developing class of structurally and compositionally complex materials that are expected to dominate the next generation of functional nanomaterials. The development of methods enabling rapid assessment of the toxicity risk associated with this type of nanomaterial is therefore critically important. We evaluated the toxicity of three differently structured nickel-silica nanomaterials as prototypical CENs: simple, surface-deposited Ni-SiO2 and hollow and non-hollow core-shell Ni@SiO2 materials (i.e., ~1–2 nm Ni nanoparticles embedded into porous silica shells with and without a central cavity, respectively). Zebrafish embryos were exposed to these CENs, and morphological (survival and malformations) and physiological (larval motility) endpoints were coupled with thorough characterization of physiochemical characteristics (including agglomeration, settling and nickel ion dissolution) to determine how toxicity differed between these CENs and equivalent quantities of Ni2+ salt (based on total Ni). Exposure to Ni2+ ions strongly compromised zebrafish larva viability, and surviving larvae showed severe malformations. In contrast, exposure to the equivalent amount of Ni CEN did not result in these abnormalities. Interestingly, exposure to Ni-SiO2 and hollow Ni@SiO2 provoked abnormalities of zebrafish larval motor function, indicating developmental toxicity, while non-hollow Ni@SiO2 showed no toxicity. Correlating these observations with physicochemical characterization of the CENs suggests that the toxicity of the Ni-SiO2 and hollow Ni@SiO2 material may result partly from an increased effective exposure at the bottom of the well due to rapid settling. Overall, our data suggest that embedding nickel NPs in a porous silica matrix may be a straightforward way to mitigate their toxicity without compromising their functional properties. At the same time, our results also indicate that it is critical to consider
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Amifostine reduces gastro-intestinal toxicity after autologous transplantation for multiple myeloma.
Malek, Ehsan; Gupta, Vinita; Creger, Richard; Caimi, Paolo; Vatsayan, Anant; Covut, Fahrettin; Bashir, Qaiser; Champlin, Richard; Delgado, Ruby; Rondon, Gabriela; Cooper, Brenda; de Lima, Marcos; Lazarus, Hillard M; Qazilbash, Muzaffar
2018-01-02
High-dose melphalan (HDM) followed by autologous hematopoietic cell transplantation (auto-HCT) remains the standard-of-care therapy for multiple myeloma (MM) even with the availability of proteasome inhibitors and immunomodulatory drugs. Gastrointestinal (GI) toxicity is the main cause of morbidity after HDM. Amifostine, a cytoprotective agent, may reduce HDM-associated GI toxicity. We conducted a case control study comparing HDM + auto-HCT with or without amifostine for MM patients. One hundred and seven patients treated at University Hospitals Cleveland Medical Center who received pre-transplant amifostine were compared to 114 patients treated at MD Anderson Cancer Center without use of this agent. Amifostine 740 mg/m 2 was administered as a bolus infusion at 24 h and 15 min before HDM. Patients' characteristics were similar in both the groups. Amifostine therapy was well tolerated without any significant adverse effects. Grade II or greater oral mucositis (27.1% vs 47.4%; p = .002), nausea (31.8% vs. 86.0%; p = .0001), vomiting (18.7% vs. 52.6%; p = .0001) and diarrhea (56.1% vs. 72.7%; p = .006) occurred less frequently in the amifostine-treated group. There was no discernable effect of amifostine on engraftment, progression-free or overall survival. Our results indicate that amifostine decreases GI toxicity while preserving anti-myeloma efficacy of HDM and auto-HCT.
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Causes of toxicity in stormwater runoff from sawmills
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bailey, H.C.; Elphick, J.R.; Potter, A.
1999-07-01
Samples of stormwater runoff from nine sawmills in British Columbia, Canada, were tested for acute toxicity with juvenile rainbow trout over a 23-month period. Forty-two of the 58 samples tested exhibited toxicity. Causes of toxicity were investigated using toxicity identification evaluation techniques. Toxicity was attributed to divalent cations, particularly zinc, in 32 of the samples. The low hardness associated with most of the samples increased the potential for metal toxicity. For example, the LC50 of zinc was 14 {micro}g/L at a hardness of 5 mg/L. Toxicity in the remaining samples was largely attributed to tannins and lignins and was associatedmore » with areas of bulk log handling. No evidence was found to indicate that antisapstain chemicals applied to freshly cut wood contributed to toxicity.« less
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Song, Ningning; Zhong, Xu; Li, Bo; Li, Jumei; Wei, Dongpu; Ma, Yibing
2014-01-01
Little knowledge is available about the influence of cation competition and metal speciation on trivalent chromium (Cr(III)) toxicity. In the present study, the effects of pH and selected cations on the toxicity of trivalent chromium (Cr(III)) to barley (Hordeum vulgare) root elongation were investigated to develop an appropriate biotic ligand model (BLM). Results showed that the toxicity of Cr(III) decreased with increasing activity of Ca2+ and Mg2+ but not with K+ and Na+. The effect of pH on Cr(III) toxicity to barley root elongation could be explained by H+ competition with Cr3+ bound to a biotic ligand (BL) as well as by the concomitant toxicity of CrOH2+ in solution culture. Stability constants were obtained for the binding of Cr3+, CrOH2+, Ca2+, Mg2+ and H+ with binding ligand: log KCrBL 7.34, log KCrOHBL 5.35, log KCaBL 2.64, log KMgBL 2.98, and log KHBL 4.74. On the basis of those estimated parameters, a BLM was successfully developed to predict Cr(III) toxicity to barley root elongation as a function of solution characteristics. PMID:25119269
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Song, Ningning; Zhong, Xu; Li, Bo; Li, Jumei; Wei, Dongpu; Ma, Yibing
2014-01-01
Little knowledge is available about the influence of cation competition and metal speciation on trivalent chromium (Cr(III)) toxicity. In the present study, the effects of pH and selected cations on the toxicity of trivalent chromium (Cr(III)) to barley (Hordeum vulgare) root elongation were investigated to develop an appropriate biotic ligand model (BLM). Results showed that the toxicity of Cr(III) decreased with increasing activity of Ca(2+) and Mg(2+) but not with K(+) and Na(+). The effect of pH on Cr(III) toxicity to barley root elongation could be explained by H(+) competition with Cr(3+) bound to a biotic ligand (BL) as well as by the concomitant toxicity of CrOH(2+) in solution culture. Stability constants were obtained for the binding of Cr(3+), CrOH(2+), Ca(2+), Mg(2+) and H(+) with binding ligand: log KCrBL 7.34, log KCrOHBL 5.35, log KCaBL 2.64, log KMgBL 2.98, and log KHBL 4.74. On the basis of those estimated parameters, a BLM was successfully developed to predict Cr(III) toxicity to barley root elongation as a function of solution characteristics.
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Toxic stress and child refugees.
Murray, John S
2018-01-01
The purpose of this article was to describe the phenomenon of toxic stress and its impact on the physical and mental health of child refugees. Almost two decades ago, researchers found that recurring adverse childhood events (ACEs; e.g., physical, psychological, and sexual abuse, neglect, and household dysfunction such as substance abuse, mental illness, and criminal behavior) were associated with a significant increase in serious illnesses during adulthood. Illnesses include heart, lung, and liver disease, cancer, and bone fractures. The scientists reported that experiencing four or more ACEs during childhood significantly increases the risk for toxic stress. Toxic stress is defined as the exposure to extreme, frequent, and persistent adverse events without the presence of a supportive caretaker. There is a paucity of literature related to toxic stress and child refugees. However, it has been clearly established that the prolonged brutal and traumatizing war in Syria is having a profound impact on the physical and mental health of child refugees at a distressing rate. Prevention of toxic stress should be a primary goal of all pediatric healthcare professionals working with child refugees. While this seems daunting given the population, and the seemingly insurmountable stressors they experience, some basic interventions should be considered. Providing basic anticipatory guidance to parents and caregivers of child refugees, to encourage positive parenting and strengthening support networks, will be highly effective in developing the requisite buffers that mitigate the effects of stress and avoid toxic stress. Efforts should also be focused on addressing caregiver stress and improving their ability to provide safe, reliable, and nurturing care that will help to mitigate any stress response experienced by a child. It is critical that greater awareness be placed on the effects of toxic stress on child refugees who are exposed to significant adverse events early in life
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Yang, Ha Na; Kim, Young Mook; Kim, Byoung Ho; Sohn, Kyoung Min; Choi, Myung Jin; Choi, Young Hee
2010-01-01
Aloe has been widely used in phytomedicine. Phytomedicine describes aloe as a herb which has anti-inflammatory, anti-proliferative, anti-aging effects. In recent years several cases of aloe-induced hepatotoxicity were reported. But its pharmacokinetics and toxicity are poorly described in the literature. Here we report three cases with aloe-induced toxic hepatitis. A 57-yr-old woman, a 62-yr-old woman and a 55-yr-old woman were admitted to the hospital for acute hepatitis. They had taken aloe preparation for months. Their clinical manifestation, laboratory findings and histologic findings met diagnostic criteria (RUCAM scale) of toxic hepatitis. Upon discontinuation of the oral aloe preparations, liver enzymes returned to normal level. Aloe should be considered as a causative agent in hepatotoxicity. PMID:20191055
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We report on a procedure using powdered coconut charcoal to sequester organic contaminants and reduce toxicity in sediments as part of a series of toxicity identification and evaluation (TIE) methods. Powdered coconut charcoal (PCC) was effective in reducing the toxicity of endos...
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Masuda, Akane; Masuda, Miyabi; Kawano, Takuya; Kitsunai, Yoko; Nakayama, Haruka; Nakajima, Hiroyuki; Kojima, Hiroyuki; Kitamura, Shigeyuki; Uramaru, Naoto; Hosaka, Takuomi; Sasaki, Takamitsu; Yoshinari, Kouichi
2017-01-01
Liver and hepatocyte hypertrophy can be induced by exposure to chemical compounds, but the mechanisms and toxicological characteristics of these phenomena have not yet been investigated extensively. In particular, it remains unclear whether the hepatocyte hypertrophy induced by chemical compounds should be judged as an adaptive response or an adverse effect. Thus, understanding of the toxicological characteristics of hepatocyte hypertrophy is of great importance to the safety evaluation of pesticides and other chemical compounds. To this end, we have constructed a database of potentially toxic pesticides. Using risk assessment reports of pesticides that are publicly available from the Food Safety Commission of Japan, we extracted all observations/findings that were based on 90-day subacute toxicity tests and 2-year chronic toxicity and carcinogenicity tests in rats. Analysis of the database revealed that hepatocyte hypertrophy was observed for 37-47% of the pesticides investigated (varying depending on sex and testing period), and that centrilobular hepatocyte hypertrophy was the most frequent among the various types of hepatocyte hypertrophy in both the 90-day and 2-year studies. The database constructed in this study enables us to investigate the relationships between hepatocyte hypertrophy and other toxicological observations/findings, and thus will be useful for characterizing hepatocyte hypertrophy.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Schwartz, Grace E.; Hower, James C.; Phillips, Allison L.
The chemical composition of coal ash is highly heterogeneous and dependent on the origin of the source coal, combustion parameters, and type and configuration of air pollution control devices. This heterogeneity results in uncertainty in the evaluation of leaching potential of contaminants from coal ash. The goal of this work was to identify whether a single leaching protocol could roughly group high-leaching potential coal ash from low-leaching potential coal ash, with respect to arsenic (As) and selenium (Se). We used four different leaching tests, including the Toxicity Characteristic Leaching Protocol (TCLP), natural pH, aerobic sediment microcosms, and anaerobic sediment microcosmsmore » on 10 different coal ash materials, including fly ash, lime-treated ash, and flue gas desulfurization materials. Leaching tests showed promise in categorizing high and low-leaching potential ash materials, indicating that a single point test could act as a first screening measure to identify high-risk ash materials. However, the amount of contaminant leached varied widely across tests, reflecting the importance of ambient conditions (pH, redox state) on leaching. These results demonstrate that on-site geochemical conditions play a critical role in As and Se mobilization from coal ash, underscoring the need to develop a situation-based risk assessment framework for contamination by coal ash pollutants.« less
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EDTA retention and emissions from remediated soil.
Jez, Erika; Lestan, Domen
2016-05-01
EDTA-based remediation is reaching maturity but little information is available on the state of chelant in remediated soil. EDTA soil retention was examined after extracting 20 soil samples from Pb contaminated areas in Slovenia, Austria, Czech Republic and USA with 120 mM kg(-1) Na2H2EDTA, CaNa2EDTA and H4EDTA for 2 and 24 h. On average, 73% of Pb was removed from acidic and 71% from calcareous soils (24 h extractions). On average, 15% and up to 64% of applied EDTA was after remediation retained in acidic soils. Much less; in average 1% and up to the 22% of EDTA was retained in calcareous soils. The secondary emissions of EDTA retained in selected remediated soil increased with the acidity of the media: the TCLP (Toxicity Characteristic Leaching Procedure) solution (average pH end point 3.6) released up to 36% of EDTA applied in the soil (28.1 mmol kg(-1)). Extraction with deionised water (pH > 6.0) did not produce measurable EDTA emissions. Exposing soil to model abiotic (thawing/freezing cycles) and biotic (ingestion by earthworms Lumbricus rubellus) ageing factors did not induce additional secondary emissions of EDTA retained in remediated soil. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Effect of coated urea on cadmium accumulation in Oryza sativa L. grown in contaminated soil.
Xu, Chao; Wu, Zisong; Zhu, Qihong; Zhu, Hanhua; Zhang, Yangzhu; Huang, Daoyou
2015-11-01
Experiments were conducted to determine the effects of three types of coated urea on the accumulation of cadmium (Cd) in rice (Oryza sativa L.) grown in contaminated soil. Pot-culture experiments were conducted in a greenhouse from July to November 2012 on the rice cultivar "Hua Hang Si Miao" in Guangzhou (China). The experimental design was completely randomized with four treatments and three replications. The treatments were control (CK) (N 0 mg/kg), prilled urea (PU) (N 200 mg/kg), polymer-coated urea (PCU) (N 200 mg/kg), and sulfur-coated urea (SCU) (N 200 mg/kg). Our results indicated that applications of PCU and SCU slightly increased the dry weight of rice grains. The application of SCU significantly decreased the CaCl2 and toxicity characteristic leaching procedure (TCLP)-extractable Cd concentrations by 15.4 and 56.1%, respectively. Sequential extractions showed that PCU and SCU applications led to a significant decrease in Cd in the exchangeable fraction and an increase in the bound iron (Fe) and manganese (Mn) oxides fractions. Cd concentrations in grains treated with PCU were reduced by 11.7%, whereas SCU significantly reduced Cd concentrations by 29.1%. SCU reduced Cd transfer from the straws to the grain. Our results demonstrated that PCU and SCU may be effective in mitigating Cd accumulation in rice grown in acidic Cd-contaminated soil, especially in plants receiving SCU.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Pires, Richard P.; Westsik, Joseph H.; Serne, R. Jeffrey
2011-07-14
Screening tests are being conducted to evaluate waste forms for immobilizing secondary liquid wastes from the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Plans are underway to add a stabilization treatment unit to the Effluent Treatment Facility to provide the needed capacity for treating these wastes from WTP. The current baseline is to use a Cast Stone cementitious waste form to solidify the wastes. Through a literature survey, DuraLith alkali-aluminosilicate geopolymer, fluidized-bed steam reformation (FBSR) granular product encapsulated in a geopolymer matrix, and a Ceramicrete phosphate-bonded ceramic were identified both as candidate waste forms and alternatives to the baseline.more » These waste forms have been shown to meet waste disposal acceptance criteria, including compressive strength and universal treatment standards for Resource Conservation and Recovery Act (RCRA) metals (as measured by the toxicity characteristic leaching procedure [TCLP]). Thus, these non-cementitious waste forms should also be acceptable for land disposal. Information is needed on all four waste forms with respect to their capability to minimize the release of technetium. Technetium is a radionuclide predicted to be in the secondary liquid wastes in small quantities, but the Integrated Disposal Facility (IDF) risk assessment analyses show that technetium, even at low mass, produces the largest contribution to the estimated IDF disposal impacts to groundwater.« less
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Nano-lead particle synthesis from waste cathode ray-tube funnel glass.
Xing, Mingfei; Zhang, Fu-Shen
2011-10-30
Waste cathode ray-tube (CRT) funnel glass is classified as hazardous waste since it contains high amount of lead. In the present study, a novel process for lead nanopowder synthesis from this type of glass was developed by combining vacuum carbon-thermal reduction and inert-gas consolidation procedures. The key trait of the process was to evaporate lead out of the glass to obtain harmless glass powder and synchronously produce lead nanoparticles. In the synthesis process, lead oxide in the funnel glass was firstly reduced to elemental lead, and evaporated rapidly in vacuum circumstance, then quenched and formed nano-size particles on the surface of the cooling device. Experimental results showed that temperature, pressure and argon gas flow rate were the major parameters controlling lead evaporation ratio and the morphology of lead nanoparticles. The maximum lead evaporation ratio was 96.8% and particles of 4-34 nm were successfully obtained by controlling the temperature, holding time, process pressure, argon gas flow rate at 1000°C, 2-4h, 500-2000 Pa, 50-200 ml/min, respectively. Toxicity characteristic leaching procedure (TCLP) results showed that lead leaching from the residue glass met the USEPA threshold. Accordingly, this study developed a practical and environmental-friendly process for detoxification and reclamation of waste lead-containing glass. Copyright © 2011 Elsevier B.V. All rights reserved.
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Zhou, Xian; Zhou, Min; Wu, Xian; Han, Yi; Geng, Junjun; Wang, Teng; Wan, Sha; Hou, Haobo
2017-09-01
Fly ash is a hazardous byproduct of municipal solid waste incineration (MSWI). Cementitious material that is based on ground-granulated blast furnace slag (GGBFS) has been tested and proposed as a binder to stabilize Pb, Cd, and Zn in MSWI fly ash (FA). Cr, however, still easily leaches from MSWI FA. Different reagents, such as ascorbic acid (VC), NaAlO 2 , and trisodium salt nonahydrate, were investigated as potential Cr stabilizers. The results of the toxicity characteristic leaching procedure (TCLP) showed that VC significantly improved the stabilization of Cr via the reduction of Cr(VI) to Cr(III). VC, however, could interfere with the hydration process. Most available Cr was transformed into stable Cr forms at the optimum VC content of 2 wt%. Cr leaching was strongly pH dependent and could be represented by a quintic polynomial model. The results of X-ray diffraction and scanning electron microscopy-energy dispersive analysis revealed that hollow spheres in raw FA were partially filled with hydration products, resulting in the dense and homogeneous microstructure of the solidified samples. The crystal structures of C-S-H and ettringite retained Zn and Cr ions. In summary, GGBFS-based cementitious material with the low addition of 2 wt% VC effectively immobilizes Cr-bearing MSWI FA. Copyright © 2017. Published by Elsevier Ltd.
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Liu, She-Jiang; Jiang, Jia-Yu; Wang, Shen; Guo, Yu-Peng; Ding, Hui
2018-03-15
Stabilization/Solidification (S/S) can be regarded as necessary for remediation of heavy metal contaminated soil. There is, however, solid agent is not very convenient to use. Water-soluble thiourea-formaldehyde (WTF) is a novel chelating agent, which has more practical applications. The process of WTF resin for S/S process of heavy metal contaminated soils was studied. Laboratory-prepared slurries, made of field soils spiked with Cd 2+ and Cr 6+ were treated with WTF resin. The toxicity characteristic leaching procedure (TCLP) showed that with 2 wt% WTF, in the neutral condition of soil after treatment for 7 d, the leaching concentrations of Cd 2+ and Cr 6+ in contaminated soil were decreased by 80.3% and 92.6% respectively. Moreover, Tessier sequence extraction procedure showed WTF resin reduced the leaching concentration by transforming heavy metal from exchange form to organic form. The structure of WTF is obtained according to elemental analysis result and reaction mechanism. Through analysis of the infrared spectrogram of WTF and WTF heavy mental chelating precipitation, WTF can form stable chelate with heavy mental through coordination. The significant groups are hydroxyl, nitrogen and sulphur function groups in WTF mainly. Toxicology test revealed that the WTF resin is nontoxic to microorganism in the soils. Copyright © 2017 Elsevier B.V. All rights reserved.
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Li, Yuan-Cheng; Min, Xiao-Bo; Chai, Li-Yuan; Shi, Mei-Qing; Tang, Chong-Jian; Wang, Qing-Wei; Liang, Yan-Jie; Lei, Jie; Liyang, Wen-Jun
2016-10-01
Wastewater treatment sludge from a primary lead-zinc smelter is characterized as hazardous waste and requires treatment prior to disposal due to its significant arsenic and heavy metals contents. This study presents a method for the stabilization of arsenic sludge that uses a slag based curing agent composed of smelting slag, cement clinker and limestone. The Unconfined Compressive Strength (UCS) test, the China Standard Leaching Test (CSLT), and the Toxicity Characteristic Leaching Procedures (TCLP) were used to physically and chemically characterize the solidified sludge. The binder ratio was determined according to the UCS and optimal experiments, and the optimal mass ratio of m (smelting slag): m (cement clinker): m (gypsum sludge): m (limestone) was 70:13:12:5. When the binder was mixed with arsenic sludge using a mass ratio of 1:1 and then maintained at 25 °C for 28 d, the UCS reached 9.30 MPa. The results indicated that the leached arsenic content was always less than 5 mg/L, which is a safe level, and does not contribute to recontamination of the environment. The arsenic sludge from the Zn/Pb metallurgy plant can be blended with cement clinker and smelting slag materials for manufacturing bricks and can be recycled as construction materials. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Lim, T T; Chu, J; Goi, M H
2006-01-01
The suitability of using cement-stabilized sludge products as artificial soils in earth works was evaluated. The sludge products investigated were cemented sludge, cement-treated clay-amended sludge (SS+MC), and cement-treated copper slag-amended sludge (SS+CS). The leachability of lead (Pb), zinc (Zn), copper (Cu), and chromium (Cr) were assessed using the sequential extraction technique, toxicity characteristic leaching procedure (TCLP), NEN 7341 availability test, and column leaching test. The results indicated that Zn leachability was reduced in all the cement-stabilized sludge products. In contrast, Cu was transferred from the organic fraction to the readily leachable phases in the cement-stabilized sludge products and therefore exhibited increased leachability. The increased Cu leachability could be attributed to dissolution of humic substances in the sludge as a result of elevated pH. Good correlation between dissolved organic carbon (DOC) and heavy metal leaching from the cement-stabilized sludge products was observed in the column leaching experiment. Even with a cement percentage as small as 12.5%, calcium silicate hydrate (C-S-H) was formed in the SS+MC and SS+CS products. Inclusion of the marine clay in the SS+MC products could reduce the leaching potentials of Zn, and this was the great advantage of the marine clay over the copper slag for sludge amendment.
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Schwartz, Grace E.; Hower, James C.; Phillips, Allison L.; ...
2018-01-23
The chemical composition of coal ash is highly heterogeneous and dependent on the origin of the source coal, combustion parameters, and type and configuration of air pollution control devices. This heterogeneity results in uncertainty in the evaluation of leaching potential of contaminants from coal ash. The goal of this work was to identify whether a single leaching protocol could roughly group high-leaching potential coal ash from low-leaching potential coal ash, with respect to arsenic (As) and selenium (Se). We used four different leaching tests, including the Toxicity Characteristic Leaching Protocol (TCLP), natural pH, aerobic sediment microcosms, and anaerobic sediment microcosmsmore » on 10 different coal ash materials, including fly ash, lime-treated ash, and flue gas desulfurization materials. Leaching tests showed promise in categorizing high and low-leaching potential ash materials, indicating that a single point test could act as a first screening measure to identify high-risk ash materials. However, the amount of contaminant leached varied widely across tests, reflecting the importance of ambient conditions (pH, redox state) on leaching. These results demonstrate that on-site geochemical conditions play a critical role in As and Se mobilization from coal ash, underscoring the need to develop a situation-based risk assessment framework for contamination by coal ash pollutants.« less
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Arsenic removal from groundwater using iron electrocoagulation: effect of charge dosage rate.
Amrose, Susan; Gadgil, Ashok; Srinivasan, Venkat; Kowolik, Kristin; Muller, Marc; Huang, Jessica; Kostecki, Robert
2013-01-01
We demonstrate that electrocoagulation (EC) using iron electrodes can reduce arsenic below 10 μg/L in synthetic Bangladesh groundwater and in real groundwater from Bangladesh and Cambodia, while investigating the effect of operating parameters that are often overlooked, such as charge dosage rate. We measure arsenic removal performance over a larger range of current density than in any other single previous EC study (5000-fold: 0.02 - 100 mA/cm(2)) and over a wide range of charge dosage rates (0.060 - 18 Coulombs/L/min). We find that charge dosage rate has significant effects on both removal capacity (μg-As removed/Coulomb) and treatment time and is the appropriate parameter to maintain performance when scaling to different active areas and volumes. We estimate the operating costs of EC treatment in Bangladesh groundwater to be $0.22/m(3). Waste sludge (~80 - 120 mg/L), when tested with the Toxic Characteristic Leachate Protocol (TCLP), is characterized as non-hazardous. Although our focus is on developing a practical device, our results suggest that As[III] is mostly oxidized via a chemical pathway and does not rely on processes occurring at the anode. Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Environmental Science and Health, Part A, to view the free supplemental file.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sadasivam, Sivachidambaram, E-mail: sadasivams@cardiff.ac.uk; Thomas, Hywel Rhys
A metakaolinite-hematite (KH) red pigment was prepared using an ocherous iron oxide sludge recovered from a water treatment plant of an abandoned coal mine. The KH pigment was prepared by heating the kaolinite and the iron oxide sludge at kaolinite's dehydroxylation temperature. Both the raw sludge and the KH specimen were characterised for their colour properties and toxic characteristics. The KH specimen could serve as a pigment for integrally coloured concrete and offers a potential use for the large volumes of the iron oxide sludge collected from mine water treatment plants. - Graphical abstract: A kaolinite based red pigment wasmore » prepared using an ocherous iron oxide sludge recovered from an abandoned coal mine water treatment plant. Display Omitted - Highlights: • A red pigment was prepared by heating a kaolinite and an iron oxide sludge. • The iron oxide and the pigment were characterised for their colour properties. • The red pigment can be a potential element for integrally coloured concrete.« less
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Allahdina, Ali M; Stetson, Paul F; Vitale, Susan; Wong, Wai T; Chew, Emily Y; Ferris, Fredrick L; Sieving, Paul A; Cukras, Catherine
2018-04-01
As optical coherence tomography (OCT) minimum intensity (MI) analysis provides a quantitative assessment of changes in the outer nuclear layer (ONL), we evaluated the ability of OCT-MI analysis to detect hydroxychloroquine toxicity. Fifty-seven predominantly female participants (91.2% female; mean age, 55.7 ± 10.4 years; mean time on hydroxychloroquine, 15.0 ± 7.5 years) were enrolled in a case-control study and categorized into affected (i.e., with toxicity, n = 19) and unaffected (n = 38) groups using objective multifocal electroretinographic (mfERG) criteria. Spectral-domain OCT scans of the macula were analyzed and OCT-MI values quantitated for each subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. A two-sample U-test and a cross-validation approach were used to assess the sensitivity and specificity of toxicity detection according to OCT-MI criteria. The medians of the OCT-MI values in all nine of the ETDRS subfields were significantly elevated in the affected group relative to the unaffected group (P < 0.005 for all comparisons), with the largest difference found for the inner inferior subfield (P < 0.0001). The receiver operating characteristic analysis of median MI values of the inner inferior subfields showed high sensitivity and high specificity in the detection of toxicity with area under the curve = 0.99. Retinal changes secondary to hydroxychloroquine toxicity result in increased OCT reflectivity in the ONL that can be detected and quantitated using OCT-MI analysis. Analysis of OCT-MI values demonstrates high sensitivity and specificity for detecting the presence of hydroxychloroquine toxicity in this cohort and may contribute additionally to current screening practices.
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Allahdina, Ali M.; Stetson, Paul F.; Vitale, Susan; Wong, Wai T.; Chew, Emily Y.; Ferris, Fredrick L.; Sieving, Paul A.
2018-01-01
Purpose As optical coherence tomography (OCT) minimum intensity (MI) analysis provides a quantitative assessment of changes in the outer nuclear layer (ONL), we evaluated the ability of OCT-MI analysis to detect hydroxychloroquine toxicity. Methods Fifty-seven predominantly female participants (91.2% female; mean age, 55.7 ± 10.4 years; mean time on hydroxychloroquine, 15.0 ± 7.5 years) were enrolled in a case-control study and categorized into affected (i.e., with toxicity, n = 19) and unaffected (n = 38) groups using objective multifocal electroretinographic (mfERG) criteria. Spectral-domain OCT scans of the macula were analyzed and OCT-MI values quantitated for each subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. A two-sample U-test and a cross-validation approach were used to assess the sensitivity and specificity of toxicity detection according to OCT-MI criteria. Results The medians of the OCT-MI values in all nine of the ETDRS subfields were significantly elevated in the affected group relative to the unaffected group (P < 0.005 for all comparisons), with the largest difference found for the inner inferior subfield (P < 0.0001). The receiver operating characteristic analysis of median MI values of the inner inferior subfields showed high sensitivity and high specificity in the detection of toxicity with area under the curve = 0.99. Conclusions Retinal changes secondary to hydroxychloroquine toxicity result in increased OCT reflectivity in the ONL that can be detected and quantitated using OCT-MI analysis. Analysis of OCT-MI values demonstrates high sensitivity and specificity for detecting the presence of hydroxychloroquine toxicity in this cohort and may contribute additionally to current screening practices. PMID:29677357
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Toxicity of pyrolysis gases from synthetic polymers
NASA Technical Reports Server (NTRS)
Hilado, C. J.; Soriano, J. A.; Kosola, K. L.; Kourtides, D. A.; Parker, J. A.
1977-01-01
The screening test method was used to investigate toxicity in polyethylene, polystyrene, polymethyl methacrylate, polyaryl sulfone, polyether sulfone, polyphenyl sulfone, and polyphenylene sulfide. Changing from a rising temperature program to a fixed temperature program resulted on shorter times to animal responses. This effect was attributed in part to more rapid generation of toxicants. The toxicants from the sulfur containing polymers appeared to act more rapidly than the toxicants from the other polymers. It was not known whether this effect was due primarily to difference in concentration or in the nature of the toxicants. The carbon monoxide concentration found did not account for the results observed with the sulfur containing polymers. Polyphenyl sulfone appeared to exhibit the least toxicity among the sulfur containing polymers evaluated under these test conditions.
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Relationship between physico-chemical characteristics and potential toxicity of PM10.
Megido, Laura; Suárez-Peña, Beatriz; Negral, Luis; Castrillón, Leonor; Suárez, Susana; Fernández-Nava, Yolanda; Marañón, Elena
2016-11-01
PM10 was sampled at a suburban location affected by traffic and industry in the north of Spain. The samples were analysed to determine the chemical components of PM10 (organic and elemental carbon, soluble chemical species and metals). The aim of this study was to assess the toxicity of PM10 in terms of the bulk analysis and the physico-chemical properties of the particles. Total carbon, sulphates, ammonium, chlorides and nitrates were found to be the major constituents of PM10. The contribution of the last of these was found to increase significantly with PM10 concentration (Pearson coefficient correlation of 0.7, p-value < 0.001). Individual airborne particles were characterised morphologically and chemically via a combination of Scanning Electron Microscopy and Energy-Dispersive X-ray spectroscopy (SEM-EDX). The subsequent image analysis revealed C-rich particles with shapes that pointed to combustion processes. Moreover, carbonaceous particles seemed to act as vehicles for sulphur compounds and metals (S, Na, Fe, Ca, Mg, K, Al, Mn, Zn and Cu). Coarse particles were found to be mainly constituted by crustal material and marine and carbonaceous particles. Although most of the studied individual particles in PM10 samples (86.0%) had a diameter within the 0.1-2.5 μm range, 1.8% of them had sizes lower than 0.1 μm 40.2% of the total studied particles were estimated to be inhaled and deposited in the human respiratory tract; 12.3% of these particles would reach the deepest zones, thereby posing a major risk to human health. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Li, Yanbin; Duan, Zhiwei; Liu, Guangliang; Kalla, Peter; Scheidt, Daniel; Cai, Yong
2015-08-18
The Florida Everglades is an environmentally sensitive wetland ecosystem with a number of threatened and endangered fauna species susceptible to the deterioration of water quality. Several potential toxic metal sources exist in the Everglades, including farming, atmospheric deposition, and human activities in urban areas, causing concerns of potential metal exposure risks. However, little is known about the pollution status of toxic metals/metalloids of potential concern, except for Hg. In this study, eight toxic metals/metalloids (Cd, Cr, Pb, Ni, Cu, Zn, As, and Hg) in Everglades soils were investigated in both dry and wet seasons. Pb, Cr, As, Cu, Cd, and Ni were identified to be above Florida SQGs (sediment quality guidelines) at a number of sampling sites, particularly Pb, which had a level of potential risk to organisms similar to that of Hg. In addition, a method was developed for quantitative source identification and controlling factor elucidation of toxic metals/metalloids by introducing an index, enrichment factor (EF), in the conventional multiple regression analysis. EFs represent the effects of anthropogenic sources on metals/metalloids in soils. Multiple regression analysis showed that Cr and Ni were mainly controlled by anthropogenic loading, whereas soil characteristics, in particular natural organic matter (NOM), played a more important role for Hg, As, Cd, and Zn. NOM may control the distribution of these toxic metals/metalloids by affecting their mobility in soils. For Cu and Pb, the effects of EFs and environmental factors are comparable, suggesting combined effects of loading and soil characteristics. This study is the first comprehensive research with a vast amount of sampling sites on the distribution and potential risks of toxic metals/metalloids in the Everglades. The finding suggests that in addition to Hg other metals/metalloids could also potentially be an environmental problem in this wetland ecosystem.
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Predictive Modeling of Developmental Toxicity
The use of alternative methods in conjunction with traditional in vivo developmental toxicity testing has the potential to (1) reduce cost and increase throughput of testing the chemical universe, (2) prioritize chemicals for further targeted toxicity testing and risk assessment,...
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Classification of Chemicals Based On Structured Toxicity Information
Thirty years and millions of dollars worth of pesticide registration toxicity studies, historically stored as hardcopy and scanned documents, have been digitized into highly standardized and structured toxicity data within the Toxicity Reference Database (ToxRefDB). Toxicity-bas...