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Using biological endpoints for assessing exposures to endocrine disrupting contaminants of emerging concern
Citation:
LAZORCHAK, J. M., H. Schoenfuss, D. C. BENCIC, A. D. BIALES, R. W. FLICK, AND C. T. NIETCH. Using biological endpoints for assessing exposures to endocrine disrupting contaminants of emerging concern. Presented at SETAC Europe, Seville, SPAIN, May 23 - 27, 2010.
Impact/Purpose:
A great deal of uncertainty exists regarding the extent to which humans and wildlife are exposed to chemical stressors in aquatic resources. Scientific literature is replete with studies of xenobiotics in surface waters, including a recent national USGS survey of endocrine disrupting chemicals; however, biological significance of these chemical data is in question since chemical bioavailability is largely unknown and biological events may be induced by undetected chemicals and varying ecological conditions (i.e., total nitrogen and phosphorus). Whole effluent toxicity data exist, but do not answer specific exposure questions that may support detailed ecological risk assessments. Interpretation of data arising from exposure to complex chemical mixtures is even more problematic. A solution to these problems is development of sensitive and specific cellular indicators of exposure in aquatic organisms. The potential for development is enhanced by emergent resources in molecular biology and associated technologies, most notably DNA microarrays consisting of transcriptionally relevant nucleic acid sequences that can be used to detect altered gene expression in cells, tissues and various life stages of organisms exposed to chemical and natural stressors.
Description:
Most of what is known about the implications of endocrine disrupting chemicals (EDCs) in the environment is site- or compound-specific. There are numerous reports of gonadal histological abnormalities, alterations in sex ratios, and high vitellogenin protein levels in fish below wastewater treatment plants. There has been some linear regression modeling describing the relationship between estrogens and relative fecundity linked to population models predicting trajectories of decreases in population and size. However, there remains no clear and direct field measured linkage between ob served abnormalities and population level effects.