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USING BIOASSAYS TO EVALUATE THE PERFORMANCE OF EDC RISK MANAGEMENT METHODS
Citation:
Acheson*, C M. USING BIOASSAYS TO EVALUATE THE PERFORMANCE OF EDC RISK MANAGEMENT METHODS. Presented at 2003 American Institute of Chemical Engineers Annual Meeting, San Francisco, CA, 11/16-21/2003.
Description:
In Superfund risk management research, the performance of risk management techniques is typically evaluated by measuring "the concentrations of the chemicals of concern before and after risk management efforts. However, using bioassays and chemical data provides a more robust understanding of the effectiveness of risk management strategies. For example, bioassay testing evaluates the aggregate effect of the environmental sample on the reporting organisms, and thus, includes aspects such as environmental matrix effects, sorption/desorption behavior, bioavailability, and chemical mixture interactions. As a result, bioassay testing can demonstrate changes in toxicity rather than inferring risk reduction from chemical concentrations. In addition, when bioassays are used to evaluate samples following risk management techniques, increased responses are observed in some cases, These increased responses may be due to incomplete treatment or toxicity introduced through process amendments. When these types of problems are identified through bioassay testing, risk management techniques can be altered to correct the problem. An example from Superfund research will be presented to illustrate the use of bioassays.
The US EPA has begun EDC research due to the potential breadth of the problem, the possibility of serious health and ecological effects, and the persistence of some EDCs in the environment. The 1imited knowledge about EDCs, such as the endocrine activity of various chemicals and their degradation products, places a greater emphasis on using bioassays to evaluate the perfonnance of EDC risk management methods. Many bioassays have been developed to identify EDCs or to characterize EDC health effects and exposure levels, and this development continues. Since risk management research has a different goal than effects and exposure research, it may be necessary to adapt assays to risk management projects.
To find an assay suitable for risk management projects, assays from the peer reviewed literature should be evaluated based on: mechanism of action, reported sensitivity, range of applications and chemicals studied, acceptance in the academic community, the details of the assay protocol, and the EDSTAC Tier I Screening Battery recommendations. For example, currently bioassays fall into three general mechanisms of action: estrogenic, androgenic, or thyroid-active. The bioassays selected should match the activity of the EDC studied. Similarly, the assay must be sensitive in the concentration range of concern. Practical concerns such as cost, time, equipment and space needs, and personnel skills should also be included in the assay selection process.
This presentation will discuss several EDC bioassays, the process of selecting appropriate EDC assays, and adapting them to fit risk management projects. A hypothetical case study illustrating the use of EDC bioassays to evaluate the effectiveness of risk management methods will also be discussed.