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SELECTING RELEVANT TEST SPECIES FOR ECOLOGICAL RISK ASSESSMENTS FOR PESTICIDES
Citation:
Pfleeger, T G., D M. Olszyk, C. A. Burdick, G. A. King, J. S. Kern, AND J S. Fletcher. SELECTING RELEVANT TEST SPECIES FOR ECOLOGICAL RISK ASSESSMENTS FOR PESTICIDES. Presented at SETAC Europe, Prague, Czech Republic, April 18-22, 2004.
Description:
In many countries, numerous tests are required prior to chemical registration for the protection of human health and the environment from the unintended effects of chemical releases. The species used in these tests are quite often familiar to scientists, have an extensive history in a variety of experiments, and are easy to manage. Currently, plant testing in the United States requires the use of ten species. All the recommended test species are annual, herbaceous crops. However, these species may not be representative of ones that will potentially be exposed. There is little evidence to suggest the species currently used are the most sensitive species to all toxicants, therefore these species may not be indicative of the effects that could occur with exposure. The data generated in these tests are used in making ecological risk assessments used by decision makers to decide the regulatory fate of a particular chemical. The uncertainty surrounding the data compels decision makers to make more restrictive choices concerning the level of risk. A more realistic approach would be to use the species most likely to be exposed to the toxicant as the test species. A method has been developed for determining test species for plant tests using a geographic information system (GIS). The GIS system developed for the conterminous United States uses information on crop location, crop diversity, herbicide use rates and wind speed to determine high risk areas. Crops, non-cultivated plants and threatened/endangered species are then identified from those areas using the GIS. These factors can then be used to determine relevant species for various exposure scenarios. Results should decrease the uncertainty associated with ecological risk assessment. The GIS can also be used for other scenarios such as locating pesticide monitoring sites, locating native plant populations in proximity to genetically modified relatives and locating potential control sites for experimental uses.