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The role of integrative, whole organism testing in monitoring applications: Back to the future
Citation:
Tietge, Joe, D. Villeneuve, AND G. Ankley. The role of integrative, whole organism testing in monitoring applications: Back to the future. Presented at International Workshop on Integrated Effect and Exposure Analysis, September 23, 2012.
Impact/Purpose:
not applicable
Description:
The biological effects of chemicals released to surface waters continue to be an area of uncertainty in risk assessment and risk management. Based on conventional risk assessment considerations, adequate exposure and effects information are required to reach a scientifically sound assessment. Analytical chemistry, as a measure of exposure, is a viable monitoring approach for those chemicals with sufficient toxicological data to establish criteria or benchmark concentrations. However, most individual chemicals lack such information, as do the variable chemical mixtures that inevitably exist in aquatic systems. Furthermore, analytical chemistry approaches to monitoring are limited by several factors, including: lack of appropriate analytical methods, insufficient detection limits, inability to aggregate effects of chemicals in mixtures, and the requirement to identify, a priori, the chemical(s) of interest. Historically, biological monitoring of wastewater effluents with in vivo tests was introduced because chemical monitoring programs were unable to predict effluent toxicity. The premise of organismal testing is that the toxicological responses of the organisms will report the integrated toxicological effects of complex mixtures. While valuable as an indicator of effects, this approach by itself is unable to provide information on the chemical composition of the mixtures and, thus, cannot determine which chemicals are related to an observed effect. This deficiency in organismal testing was addressed by the introduction of the Toxicity Identification Evaluations (TIE) approach. TIE methods employ a variety of physico-chemical manipulations of samples to produce simplified fractions of the original effluent that are then tested in a biological system for a relevant response. Fractions that are active in the biological system are further manipulated to the extent feasible, depending on the nature of the sample, which ultimately could lead to identification of the chemic