A review of the tissue residue approach for organic and organometallic compounds in aquatic organisms

Abstract

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. Application of the TRA to various baseline toxicants as well as substances with specific modes of action via receptor-mediated processes, such as chlorinated aromatic hydrocarbons, pesticides, and organometallics is discussed, as is application of TRA concepts in field assessments of tissue residues. In contrast to media-based toxicity relationships, CBR values tend to be less variable and less influenced by factors that control bioavailability and bioaccumulation, and TRA can be used to infer mechanisms of toxic action, evaluate the toxicity of mixtures, and interpret field data on bioaccumulated toxicants. If residue-effects data are not available, body residues can be estimated, as has been done using the target lipid model for baseline toxicants, to derive critical values for risk assessment. One of the primary unresolved issues complicating TRA for organic chemicals is biotransformation. Further work on the influence of biotransformation, a better understanding of contaminant lipid interactions, and an explicit understanding of the time dependency of CBRs and receptor-mediated toxicity are all required to advance this field. Additional residue-effects data on sublethal endpoints, early life stages, and a wider range of legacy and emergent contaminants will be needed to improve the ability to use TRA for organic and organometallic compounds.

Regulation of body metal concentrations: Toxicokinetics of cadmium and zinc in crickets

“…Concentration-effect relationships based on internal body concentrations are often less variable among species, chemicals and different environmental conditions than those based on exposure concentrations (McElroy et al, 2010). Moreover, Van Straalen et al (2005) showed that sub-lethal effects of Zn on the isopod Porcelio scaber depended on the rate at which Zn entered the organism, rather than on the internal Zn concentration Fig.…”

From Incorporation to Toxicity

“…The majority of the data originates from acute toxicity studies thus the most frequent endpoint is lethality and the use of sublethal endpoints is highly desirable for a better link to population-level effects (Chapters 6 and 7). Desirable attributes that should be considered when developing databases of critical body residues have been summarized in McElroy et al (2011). Concentrations of hydrophobic organic compounds are usually normalized to lipid content to minimize intra-and interspecific variability.…”

Processes, Assessment and Remediation of Contaminated Sediments

“…For those with higher variability, the use of tissue residues based on a species sensitivity distribution would be the most appropriate method for determining the critical body burden for protecting the most sensitive species (Steevens et al, 2005). The application of the TRA approach for the evaluation of effects elicited by non-polar organic compounds and organometallic compounds has been critically reviewed and its strengths and limitations discussed (Barron et al, 2002;Landrum and Meador, 2002;McElroy et al, 2011;McCarty et al, 2011). For metals, the application of whole-body residues as threshold criteria associated with effects does not lead to a defensible prediction of risk to the organism largely due to the existence of metal-and species-specific physiological mechanisms that facilitate acclimation to metal exposure .…”