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A REGIONAL APPROACH TO ECOLOGICAL RISK ASSESSMENTS FOR PESTICIDE REGISTRATION
Citation:
Pfleeger, T G., D M. Olszyk, E H. Lee, G. A. King, J. S. Kern, AND M. Plocher. A REGIONAL APPROACH TO ECOLOGICAL RISK ASSESSMENTS FOR PESTICIDE REGISTRATION. Presented at Society of Environmental Toxicology and Chemistry, Austin, TX, November 9-13, 2003.
Description:
Currently, most ecological risk assessments for EPA pesticide registration are evaluated at the national scale using a predetermined list of test species (OPPTS 850.4225 and 8504250) as a model system with little regard to where and how the product will ultimately be used. The assumption is that the test species presently used are representative and inclusive and therefore protective of all species within the United States and in many cases other parts of the world. EPA scientists at the Corvallis, OR laboratory have developed a research program to test this assumption using a GIS (geographic information system) approach. The GIS will be used to select test species based on identification of areas within the United States that are at high risk from off target movement of herbicides. Areas considered to be at high risk are those that have: 1) a high percentage of agricultural land treated with herbicides; 2) high herbicide application rates lb/acre; 3) high density of diversified agriculture; 4) daily mean wind speeds of 9 mph or greater during the growing season; 5) presence of ecologically important or rare/endangered plant species. A prototype of this methodology indicated counties in the US corn belt at the highest risk based on these criteria. We further investigated the acreage of other, non-target, crops, dominant native plant species, plant species important for wildlife and rare/endangered plant species. Ecologically and/or economically important plant species commonly found in the corn belt that were deemed to be potentially at risk from off target movement of herbicides have been identified. These species are being grown in a greenhouse to develop suitable culture practices and to examine their sensitivity to a range of herbicide classes. This research is designed to provide more accurate test protocols by giving careful consideration to the differences in ecological and agricultural conditions that prevail in different regions of the US that are prone to the influence of non-target exposures and plant response.