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Adverse Outcome Pathways: A Conceptual Framework to Support Ecotoxicology Research and Risk Assessment
Citation:
BENNETT, R. S., R. J. ERICKSON, D. HOFF, M. W. HORNUNG, R. D. JOHNSON, D. R. MOUNT, J. W. NICHOLS, C. L. RUSSOM, P. K. SCHMIEDER, J. A. SERRANO, J. E. TIETGE, AND D. L. VILLENEUVE. Adverse Outcome Pathways: A Conceptual Framework to Support Ecotoxicology Research and Risk Assessment. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 29(3):730-741, (2010).
Impact/Purpose:
Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help meet these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk--effects on survival, development and reproduction in individuals and, by extension, impacts on populations. In this paper we present a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In concluding sections of the paper, we discuss how AOPs can help guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework.
Description:
Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help meet these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk--effects on survival, development and reproduction in individuals and, by extension, impacts on populations. In this paper we present a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In concluding sections of the paper, we discuss how AOPs can help guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework.