LISA TOLBERT
Ambient Concentrations of Organophosphorus Pesticides Caused by Volatilization
During Seasonal Pesticide Application
Environmental Health, MS
Preceptor: Michael Yost, PhD
As populations within the United States have grown and expanded into formerly low population density agricultural areas, pesticide application practices have caused increasing concern over the health of those living in nearby communities, particularly for children. One source of pesticide exposure in these nearby communities is termed indirect, secondary, or post-application pesticide drift, which is defined as the airborne movement of pesticides beyond the intended target area due to volatilization from surfaces where pesticides were initially deposited or by wind transfer of aerosolized pesticide particles or pesticides adsorbed to particulate matter.
This study is a pilot evaluation of post-application pesticide volatilization within an agricultural community in Eastern Washington. By measuring ambient air concentrations of the organophosphorus (OP) pesticides that are typically applied in the area over a majority of the 2006 pesticide spray season, we were able to assess the temporal fluctuations in volatilized pesticide concentrations as well as how the concentrations compared spatially between two areas of the community that differed in distance from suspected pesticide application sites. Our hypotheses were: (1) pesticide levels will be elevated coincident with the spray season in both monitoring areas; and (2) the more “rural” area of the community will contain higher pesticide concentrations than the more “urban” area. Following analysis of ambient air sampling results, pesticide concentrations were found to significantly vary with time throughout the monitoring period. However, no significant difference was observed in pesticide concentrations between the more rural area of the agricultural community and the more urban area. Based on these results, future ambient air monitoring planned for the project area should be designed so that sampling is performed frequently to capture day-to-day variations in pesticide concentrations, but should not focus on sampling in many locations considering that the community air shed is indicated to be well-mixed.
