Publications by authors named "Nancy Beckvar"

The study goal was to develop a sediment polychlorinated biphenyl (PCB) dose-response model based on benthic invertebrate effects to PCBs. The authors used an equilibrium partitioning (EqP) approach to generate predicted PCB sediment effect concentrations (largely Aroclor 1254) associated with a gradient of toxic effects in benthic organisms from effects observed in aquatic toxicity studies. The present study differs from all other EqP collective sediment investigations in that the authors examined a common dose-response gradient of effects for PCBs rather than a single, protective value.

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This paper reviews the tissue residue approach (TRA) for toxicity assessment as it applies to organic chemicals and some organometallic compounds (Sn, Hg, and Pb) in aquatic organisms. Specific emphasis was placed on evaluating key factors that influence interpretation of critical body residue (CBR) toxicity metrics including data quality issues, lipid dynamics, choice of endpoints, processes that alter toxicokinetics and toxicodynamics, phototoxicity, species- and life stage-specific sensitivities, and biotransformation. The vast majority of data available on TRA is derived from laboratory studies of acute lethal responses to organic toxicants exhibiting baseline toxicity.

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Dose-response relationships for aquatic organisms have been developed for numerous contaminants using external media exposures (water and sediment). Dose-response relationships based on internal concentrations (tissue residues) are limited. The present study reports Hg dose-response curves for early life stage and juvenile or adult fish based on published tissue-residue toxicity studies.

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A variety of methods have been used by numerous investigators attempting to link tissue concentrations with observed adverse biological effects. This paper is the first to evaluate in a systematic way different approaches for deriving protective (i.e.

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