The Washington aerial spray drift study: assessment of off-target organophosphorus insecticide atmospheric movement by plant surface volatilization.
Ramaprasada-J; Tsaia-YM; Eigethuna-K; Hebertb-RV; Felsot-A; Yosta-GM; Fenskea-AR
Atmos Environ 2004 Oct; 38(33):5703-5713
Post-application pesticide emissions from wetted leaf surfaces and soil may present a significant pathway of exposure to humans in nearby residential communities. In this study, high volume air sampling was performed to measure airborne concentrations of the pesticide methamidophos in a residential community in close proximity to aerial spraying. Sampling occurred before, during and 24 h post-application. To evaluate whether predictive models could reliably estimate residential exposure to methamidophos, an emission factor was used for estimating fluxes of volatilized material over the sprayed area for a I-day post-application period. These flux estimates were then incorporated into a fugitive dust gaussian dispersion model (FDM) for assessing distribution of mass around the sprayed area. The predictive model output was compared with the field air sampler measurements. In our comparison, I-day flux estimates from the model were found to be associated to observed field measurement data, with an r2 = 0.63 the day of the spray and r2 = 0.67 the day after the spray. The volatilization model however appears to underestimate surface emission flux immediately after the spray and overestimate the emission the next day.
Insecticides; Insecticide-poisoning; Emission-sources; Soil-sampling; Exposure-levels; Air-sampling; Air-contamination; Air-monitoring; Pesticides; Air-sampling-equipment
Jaya Ramaprasad, Department of Environmental and Occupational Health Sciences. School of Public Health. University of Washington, Box 357234. Seattle, WA 98195-7234
University of Washington