The Experts below are selected from a list of 47562 Experts worldwide ranked by ideXlab platform
William J. Adams - One of the best experts on this subject based on the ideXlab platform.
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Setting site-specific Water-Quality Standards by using tissue residue criteria and bioaccumulation data. Part 1. Methodology
Environmental Toxicology and Chemistry, 2005Co-Authors: John Toll, Kevin V. Brix, David K. Deforest, Lucinda M. Tear, William J. AdamsAbstract:We have developed a method for determining site-specific Water-Quality Standards (SSWQSs) for substances regulated based on tissue residues. The method uses a multisite regression model to solve for the conditional prior probability density function (PDF) on Water concentration, given that tissue concentration equals a tissue residue threshold. The method then uses site-specific Water and tissue concentration data to update the probabilities on a Monte Carlo sample of the prior PDF by using Bayesian Monte Carlo analysis. The resultant posterior PDF identifies the Water concentration that, if met at the site, would provide a desired level of confidence of meeting the tissue residue threshold contingent on model assumptions. This allows for derivation of a SSWQS. The method is fully reproducible, statistically rigorous, and easily implemented. A useful property of the method is that the model is sensitive to the amount of site-specific data available, that is, a more conservative or protective number (Water concentration) is derived when the data set is small or the variance is large. Likewise, as the site Water concentration increases above the Water-Quality standard, more site-specific information is needed to demonstrate a safe concentration at the site. A companion paper demonstrates the method by using selenium as an example.
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Setting site-specific Water-Quality Standards by using tissue residue thresholds and bioaccumulation data. Part 2. Calculating site-specific selenium Water-Quality Standards for protecting fish and birds
Environmental Toxicology and Chemistry, 2005Co-Authors: Kevin V. Brix, David K. Deforest, John Toll, Lucinda M. Tear, William J. AdamsAbstract:In a companion paper, a method for deriving tissue residue-based site-specific Water-Quality Standards (SSWQSs) was described. In this paper, the methodology is applied to selenium (Se) as an example. Models were developed to describe Se bioaccumulation in aquatic-dependent bird eggs and whole fish. A simple log-linear model best described Se accumulation in bird eggs (r2 = 0.50). For fish, separate hockey stick regressions were developed for lentic (r2 = 0.65) and lotic environments (r2 = 0.37). The low r2 value for the lotic fish model precludes its reliable use at this time. Corresponding tissue residue criteria (i.e., tissue thresholds) for bird eggs and whole fish also were identified and example model predictions were made. The models were able to predict SSWQSs over a wide range of Water-tissue combinations that might be encountered in the environment. The models also were shown to be sensitive to variability in measured tissue residues with relatively small changes in variability (as characterized by the standard error) resulting in relatively large differences in SSWQSs.
John Toll - One of the best experts on this subject based on the ideXlab platform.
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Setting site-specific Water-Quality Standards by using tissue residue criteria and bioaccumulation data. Part 1. Methodology
Environmental Toxicology and Chemistry, 2005Co-Authors: John Toll, Kevin V. Brix, David K. Deforest, Lucinda M. Tear, William J. AdamsAbstract:We have developed a method for determining site-specific Water-Quality Standards (SSWQSs) for substances regulated based on tissue residues. The method uses a multisite regression model to solve for the conditional prior probability density function (PDF) on Water concentration, given that tissue concentration equals a tissue residue threshold. The method then uses site-specific Water and tissue concentration data to update the probabilities on a Monte Carlo sample of the prior PDF by using Bayesian Monte Carlo analysis. The resultant posterior PDF identifies the Water concentration that, if met at the site, would provide a desired level of confidence of meeting the tissue residue threshold contingent on model assumptions. This allows for derivation of a SSWQS. The method is fully reproducible, statistically rigorous, and easily implemented. A useful property of the method is that the model is sensitive to the amount of site-specific data available, that is, a more conservative or protective number (Water concentration) is derived when the data set is small or the variance is large. Likewise, as the site Water concentration increases above the Water-Quality standard, more site-specific information is needed to demonstrate a safe concentration at the site. A companion paper demonstrates the method by using selenium as an example.
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Setting site-specific Water-Quality Standards by using tissue residue thresholds and bioaccumulation data. Part 2. Calculating site-specific selenium Water-Quality Standards for protecting fish and birds
Environmental Toxicology and Chemistry, 2005Co-Authors: Kevin V. Brix, David K. Deforest, John Toll, Lucinda M. Tear, William J. AdamsAbstract:In a companion paper, a method for deriving tissue residue-based site-specific Water-Quality Standards (SSWQSs) was described. In this paper, the methodology is applied to selenium (Se) as an example. Models were developed to describe Se bioaccumulation in aquatic-dependent bird eggs and whole fish. A simple log-linear model best described Se accumulation in bird eggs (r2 = 0.50). For fish, separate hockey stick regressions were developed for lentic (r2 = 0.65) and lotic environments (r2 = 0.37). The low r2 value for the lotic fish model precludes its reliable use at this time. Corresponding tissue residue criteria (i.e., tissue thresholds) for bird eggs and whole fish also were identified and example model predictions were made. The models were able to predict SSWQSs over a wide range of Water-tissue combinations that might be encountered in the environment. The models also were shown to be sensitive to variability in measured tissue residues with relatively small changes in variability (as characterized by the standard error) resulting in relatively large differences in SSWQSs.
Kevin V. Brix - One of the best experts on this subject based on the ideXlab platform.
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Setting site-specific Water-Quality Standards by using tissue residue criteria and bioaccumulation data. Part 1. Methodology
Environmental Toxicology and Chemistry, 2005Co-Authors: John Toll, Kevin V. Brix, David K. Deforest, Lucinda M. Tear, William J. AdamsAbstract:We have developed a method for determining site-specific Water-Quality Standards (SSWQSs) for substances regulated based on tissue residues. The method uses a multisite regression model to solve for the conditional prior probability density function (PDF) on Water concentration, given that tissue concentration equals a tissue residue threshold. The method then uses site-specific Water and tissue concentration data to update the probabilities on a Monte Carlo sample of the prior PDF by using Bayesian Monte Carlo analysis. The resultant posterior PDF identifies the Water concentration that, if met at the site, would provide a desired level of confidence of meeting the tissue residue threshold contingent on model assumptions. This allows for derivation of a SSWQS. The method is fully reproducible, statistically rigorous, and easily implemented. A useful property of the method is that the model is sensitive to the amount of site-specific data available, that is, a more conservative or protective number (Water concentration) is derived when the data set is small or the variance is large. Likewise, as the site Water concentration increases above the Water-Quality standard, more site-specific information is needed to demonstrate a safe concentration at the site. A companion paper demonstrates the method by using selenium as an example.
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Setting site-specific Water-Quality Standards by using tissue residue thresholds and bioaccumulation data. Part 2. Calculating site-specific selenium Water-Quality Standards for protecting fish and birds
Environmental Toxicology and Chemistry, 2005Co-Authors: Kevin V. Brix, David K. Deforest, John Toll, Lucinda M. Tear, William J. AdamsAbstract:In a companion paper, a method for deriving tissue residue-based site-specific Water-Quality Standards (SSWQSs) was described. In this paper, the methodology is applied to selenium (Se) as an example. Models were developed to describe Se bioaccumulation in aquatic-dependent bird eggs and whole fish. A simple log-linear model best described Se accumulation in bird eggs (r2 = 0.50). For fish, separate hockey stick regressions were developed for lentic (r2 = 0.65) and lotic environments (r2 = 0.37). The low r2 value for the lotic fish model precludes its reliable use at this time. Corresponding tissue residue criteria (i.e., tissue thresholds) for bird eggs and whole fish also were identified and example model predictions were made. The models were able to predict SSWQSs over a wide range of Water-tissue combinations that might be encountered in the environment. The models also were shown to be sensitive to variability in measured tissue residues with relatively small changes in variability (as characterized by the standard error) resulting in relatively large differences in SSWQSs.
Guoqiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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attempt of basin scale sediment Quality standard establishment for heavy metals in coastal rivers
Chemosphere, 2020Co-Authors: Qunqun Liu, Yanqing Sheng, Ming Jiang, Guoqiang ZhaoAbstract:Heavy metal sediment Quality Standards (SQSs) derived from sediment Quality guidelines (SQGs) are crucial in risk evaluation and environmental management. However, the establishment of SQSs is quite complex, especially for heavy metals. This study attempted to establish basin-scale SQSs for Cd, Cu, Pb and Zn based on SQGs combined with Water Quality Standards in two coastal rivers in North China, named Jiaolai River (JL) and Jiahe River (JR), respectively. The spatial distribution, fraction, partition coefficients and environmental risk of heavy metals in sediments-poreWater were investigated. The results showed that most heavy metals in sediments in JH were higher than those in JL, however, in the poreWater, it exhibited an opposite trend. The geochemical fraction showed that most heavy metals in sediments were dominated by residual fraction. The partition of heavy metals between sediment and poreWater were mainly affected by both sediment and poreWater properties, and exogenous input of heavy metals. Contamination factors showed that Cd in sediment posed high pollution degree; the interstitial Water criteria toxicity units and Nemerow Indexes suggested that heavy metal toxicities in poreWater were low. The basin-scale heavy metal SQGs were calculated based on poreWater Quality derived from surface Water Quality Standards using the modified equilibrium partitioning approach. The basin-scale heavy metal SQGs was classified with different grades to deduce the SQSs. Evaluated results of heavy metals in sediments based on SQSs showed lower potential bio-toxic effects in two rivers. In total, basin-scale SQGs for heavy metals were feasible for basin-scale SQSs establishment in coastal rivers.
Lucinda M. Tear - One of the best experts on this subject based on the ideXlab platform.
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Setting site-specific Water-Quality Standards by using tissue residue criteria and bioaccumulation data. Part 1. Methodology
Environmental Toxicology and Chemistry, 2005Co-Authors: John Toll, Kevin V. Brix, David K. Deforest, Lucinda M. Tear, William J. AdamsAbstract:We have developed a method for determining site-specific Water-Quality Standards (SSWQSs) for substances regulated based on tissue residues. The method uses a multisite regression model to solve for the conditional prior probability density function (PDF) on Water concentration, given that tissue concentration equals a tissue residue threshold. The method then uses site-specific Water and tissue concentration data to update the probabilities on a Monte Carlo sample of the prior PDF by using Bayesian Monte Carlo analysis. The resultant posterior PDF identifies the Water concentration that, if met at the site, would provide a desired level of confidence of meeting the tissue residue threshold contingent on model assumptions. This allows for derivation of a SSWQS. The method is fully reproducible, statistically rigorous, and easily implemented. A useful property of the method is that the model is sensitive to the amount of site-specific data available, that is, a more conservative or protective number (Water concentration) is derived when the data set is small or the variance is large. Likewise, as the site Water concentration increases above the Water-Quality standard, more site-specific information is needed to demonstrate a safe concentration at the site. A companion paper demonstrates the method by using selenium as an example.
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Setting site-specific Water-Quality Standards by using tissue residue thresholds and bioaccumulation data. Part 2. Calculating site-specific selenium Water-Quality Standards for protecting fish and birds
Environmental Toxicology and Chemistry, 2005Co-Authors: Kevin V. Brix, David K. Deforest, John Toll, Lucinda M. Tear, William J. AdamsAbstract:In a companion paper, a method for deriving tissue residue-based site-specific Water-Quality Standards (SSWQSs) was described. In this paper, the methodology is applied to selenium (Se) as an example. Models were developed to describe Se bioaccumulation in aquatic-dependent bird eggs and whole fish. A simple log-linear model best described Se accumulation in bird eggs (r2 = 0.50). For fish, separate hockey stick regressions were developed for lentic (r2 = 0.65) and lotic environments (r2 = 0.37). The low r2 value for the lotic fish model precludes its reliable use at this time. Corresponding tissue residue criteria (i.e., tissue thresholds) for bird eggs and whole fish also were identified and example model predictions were made. The models were able to predict SSWQSs over a wide range of Water-tissue combinations that might be encountered in the environment. The models also were shown to be sensitive to variability in measured tissue residues with relatively small changes in variability (as characterized by the standard error) resulting in relatively large differences in SSWQSs.
