Aquatic toxicologist and ecological risk assessor. Research interests in ecological risks to aquatic life from bioaccumulated tissue residues. Also interested in water quality and sediment quality criteria, toxicity testing in water and sediment.
Environmental toxicology and chemistry, Jan 14, 2018
There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory ... more There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory and behavioral impairment in aquatic organisms. We compiled Cu toxicity data for these and other sublethal endpoints in 35 tests with saltwater organisms and compared the Cu toxicity thresholds to biotic ligand model (BLM)-based estimated chronic limits (ECL values, which are EC20 values [20% effect concentrations] for the embryo-larval life stage of the blue mussel [Mytilus edulis]-a sensitive saltwater species to Cu that has historically been used to derive saltwater Cu criteria). Only eight of the 35 tests had sufficient toxicity and chemistry data to support unequivocal conclusions (i.e., a Cu EC20 or no-observed-effect concentration could be derived; and Cu and DOC concentrations were measured [or DOC concentrations could be inferred from the test-water source]). The BLM-based ECL values would have been protective (i.e., the ECL was lower than the toxicity threshold) in seven of tho...
A simple sounding yet difficult to answer question is “What concentration of a chemical in the ti... more A simple sounding yet difficult to answer question is “What concentration of a chemical in the tissues of aquatic biota is harmful to the biota itself?” This question is of particular importance in ecological risk assessment, where measurements of chemical residues in aquatic biota are often available, but the interpretation of their effect on biota is difficult. The objective of this work was to define tissue residues for a number of chemicals which, if not exceeded, pose little threat of risk to aquatic biota. These tissue screening concentrations (TSCs) were designed to be nonsiteor species-specific indicators of low risk residue levels. TSCs have been derived for 152 chemicals, both metals and organics, using a one-compartment first-order kinetic model. These TSC values are currently being used in ecological risk assessments to identify chemicals of potential concern, thus narrowing the focus of the risk assessment. To confirm the validity of the TSCs, a literature review of who...
Concentrations of the heavy metals cadmium (Cd) and zinc (Zn) were determined at several sites in... more Concentrations of the heavy metals cadmium (Cd) and zinc (Zn) were determined at several sites in Palestine Lake, Indiana, and in the stream (Williamson Ditch) which transports metal-bearing wastes to the lake. Average dissolved Cd and Zn concentrations in the lake ...
Environmental toxicology and chemistry, Jan 14, 2018
There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory ... more There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory and behavioral impairment in aquatic organisms. We compiled Cu toxicity data for these and other sublethal endpoints in 35 tests with saltwater organisms and compared the Cu toxicity thresholds to biotic ligand model (BLM)-based estimated chronic limits (ECL values, which are EC20 values [20% effect concentrations] for the embryo-larval life stage of the blue mussel [Mytilus edulis]-a sensitive saltwater species to Cu that has historically been used to derive saltwater Cu criteria). Only eight of the 35 tests had sufficient toxicity and chemistry data to support unequivocal conclusions (i.e., a Cu EC20 or no-observed-effect concentration could be derived; and Cu and DOC concentrations were measured [or DOC concentrations could be inferred from the test-water source]). The BLM-based ECL values would have been protective (i.e., the ECL was lower than the toxicity threshold) in seven of tho...
Environmental toxicology and chemistry, Jan 14, 2018
There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory ... more There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory and behavioral impairment in aquatic organisms. We compiled Cu toxicity data for these and other sublethal endpoints in 35 tests with saltwater organisms and compared the Cu toxicity thresholds to biotic ligand model (BLM)-based estimated chronic limits (ECL values, which are EC20 values [20% effect concentrations] for the embryo-larval life stage of the blue mussel [Mytilus edulis]-a sensitive saltwater species to Cu that has historically been used to derive saltwater Cu criteria). Only eight of the 35 tests had sufficient toxicity and chemistry data to support unequivocal conclusions (i.e., a Cu EC20 or no-observed-effect concentration could be derived; and Cu and DOC concentrations were measured [or DOC concentrations could be inferred from the test-water source]). The BLM-based ECL values would have been protective (i.e., the ECL was lower than the toxicity threshold) in seven of tho...
A simple sounding yet difficult to answer question is “What concentration of a chemical in the ti... more A simple sounding yet difficult to answer question is “What concentration of a chemical in the tissues of aquatic biota is harmful to the biota itself?” This question is of particular importance in ecological risk assessment, where measurements of chemical residues in aquatic biota are often available, but the interpretation of their effect on biota is difficult. The objective of this work was to define tissue residues for a number of chemicals which, if not exceeded, pose little threat of risk to aquatic biota. These tissue screening concentrations (TSCs) were designed to be nonsiteor species-specific indicators of low risk residue levels. TSCs have been derived for 152 chemicals, both metals and organics, using a one-compartment first-order kinetic model. These TSC values are currently being used in ecological risk assessments to identify chemicals of potential concern, thus narrowing the focus of the risk assessment. To confirm the validity of the TSCs, a literature review of who...
Concentrations of the heavy metals cadmium (Cd) and zinc (Zn) were determined at several sites in... more Concentrations of the heavy metals cadmium (Cd) and zinc (Zn) were determined at several sites in Palestine Lake, Indiana, and in the stream (Williamson Ditch) which transports metal-bearing wastes to the lake. Average dissolved Cd and Zn concentrations in the lake ...
Environmental toxicology and chemistry, Jan 14, 2018
There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory ... more There is concern whether regulatory criteria for copper (Cu) are protective against chemosensory and behavioral impairment in aquatic organisms. We compiled Cu toxicity data for these and other sublethal endpoints in 35 tests with saltwater organisms and compared the Cu toxicity thresholds to biotic ligand model (BLM)-based estimated chronic limits (ECL values, which are EC20 values [20% effect concentrations] for the embryo-larval life stage of the blue mussel [Mytilus edulis]-a sensitive saltwater species to Cu that has historically been used to derive saltwater Cu criteria). Only eight of the 35 tests had sufficient toxicity and chemistry data to support unequivocal conclusions (i.e., a Cu EC20 or no-observed-effect concentration could be derived; and Cu and DOC concentrations were measured [or DOC concentrations could be inferred from the test-water source]). The BLM-based ECL values would have been protective (i.e., the ECL was lower than the toxicity threshold) in seven of tho...
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