A Wind Tunnel Model to Predict Exposure of Humans and the Environment to Pesticide Drift

  • Hall, Franklin;
  • Kirchner, L. M.;
  • Taylor, R. A. J.

Pesticides and other hazardous chemicals in the environment are of growing concern as to the "real" risk to an expanding Ohio population. Exposure assessment is a vital component of the quantitative risk assessment procedures utilized to produce pesticide regulatory decisions. The EPA has published general guidelines for exposure assessments. LPCAT is currently evaluating the capture efficiencies of passive dosimeters (as part of a USEPA grant), and has developed a wind tunnel model to predict exposure related to pesticide drift to humans and water in the immediate vicinity. Meteorological conditions, exposure duration, type of exposure (activity pattern by species), and active ingredient (AI) formulation and application technologies are all important in establishing real risk (hazard) projections or risk reduction strategies. Further confounding the issue are the differential capture efficiencies expressed by various dosimeters, human skin, and protective clothing, as well as non-target species. Neglect of these differences can mislead the risk assessment resolution.

A novel system has been devised for examining the relative capture efficiencies of dosimeters. Capture efficiency is defined as the mass of material captured by an object (dosimeter) placed in an air stream relative to the mass of material that would pass through the targets projected area, had it not been there. The system is comprised of the following components: wind tunnel, fluorescent tracer solution, an atomizer and the capture efficiency test device. Data are presented on the standardization of the model and examples of capture efficiencies of several commonly utilized dosimeters. The proposed system is flexible in terms of duration of exposure, drop-sizes used, and amount of material introduced to the device. Thus, in addition to the wind tunnel laboratory studies, the system may be used to monitor exposure hazards in an array of real-world application scenarios. The potential utilization of such knowledge and monitoring technology is expected to be incorporated into the NIOSH supported study "Ohio Farm Family Health and Hazard Surveillance Program", Jay Wilkins (PI). Exposure of farm families to pesticides will be one of the safety hazards monitored in the Ohio study. This model can thus be validated as a tool to quantify off-site exposure to pesticides. The data should allow a better understanding and, hence, characterization of potential chemical risks via various routes of exposure for farm families.

This research abstract was extracted from a portion of the proceedings of "Agricultural Safety and Health: Detection, Prevention and Intervention," a conference presented by the Ohio State University and the Ohio Department of Health, sponsored by the Centers for Disease Control/National Institute for Occupational Safety and Health.

The authors noted above are from: All from the Laboratory for Pest Control Application Technology, The Ohio State University, Wooster, OH.

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