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Considerations in the Derivation of Water Quality Criteria for Endocrine-disrupting Chemicals
Citation:
ANKLEY, G. T., J. BEAMAN, R. J. ERICKSON, D. HOFF, J. M. LAZORCHAK, T. LINTON, AND D. R. MOUNT. Considerations in the Derivation of Water Quality Criteria for Endocrine-disrupting Chemicals. Presented at SETAC Annual Meeting, Tampa, FL, November 16 - 20, 2008.
Impact/Purpose:
This talk will provide an overview of these technical challenges and provide recommendations as to how they can be addressed using the model steroidal estrogen, 17á-ethinylestradiol, as a case example.
Description:
When the USEPA’s 1985 guidelines for deriving numerical water quality criteria (WQC) for the protection of aquatic life were developed there was little anticipation that endocrine-disrupting chemicals (EDCs) would be come a widespread environmental issue. While the basic guidelines provide a solid framework for developing protective WQC for EDCs, recent research has demonstrated that some EDCs (e.g., steroidal estrogens and androgens) have unique characteristics that affect exactly how the guidelines could/should be applied. For example, many EDCs are extremely potent in terms of chronic developmental and reproductive effects while causing little acute lethality, and consequently have acute:chronic effect ratios of 1000 or higher. This has repercussions for the need for, or utility of extensive acute toxicity data for criteria derivation. EDCs also tend to be quite specific in their toxic mechanism of action, such that some phyla can be far more sensitive than others. For example, fish are orders of magnitude more sensitive than invertebrates to estrogens, such that requiring collection of large amounts of toxicity data for invertebrates would have little effect on WQC derivation for this class of chemicals. EDC specificity also has implications for test design and endpoints used for WQC toxicity datasets. Some historically useful test designs (e.g., early-life stage exposures with fish) are unlikely to be effective because biological responses potentially most sensitive to EDCs are not included. Alternatively, some endpoints not typically employed for WQC derivation in the past (e.g., histopathology) could prove of significant utility. This talk will provide an overview of these technical challenges and provide recommendations as to how they can be addressed using the model steroidal estrogen, 17á-ethinylestradiol, as a case example.