Exposure received from application of animal insecticides

Part of an investigation of data collection methods in epidemiologic studie s of farmers evaluated exposures received by farmers from the application o f insecticides to animals. Twenty farmers were monitored during a normal ap plication using a fluorescent dye surrogate for the active ingredient (Al). Two exposure measures were estimated, Al concentration and the time-weight ed average for the application period (TWA(a)). Four application methods we re used: high- (n=5) and low-pressure (n=3) spraying, backpack (n=2) and po ur-on (n=10). The two farmers using a backpack sprayer had nondetectable le vels of dye. Only two of the farmers using the pour-on method had detectabl e dye levels, but these levels were high. All of the low- and high-pressure sprayers had detectable amounts of dye, Multiple layers of clothing, glove s, and boots (n=10) were associated with a low mean Al concentration for th e exposed farmers (18 mu g) and more than two-thirds of the farmers wearing this amount of clothing had nondetectable exposures. In contrast, clothing providing little or no protection was associated with a significantly high er (p<0.01) average Al concentration (4420 mu g), and less than a third of the farmers with this degree of protection had nondetectable exposures. Poo r work practices (leaking equipment, contact with wet animals or fences, an d back splash) were associated with statistically higher exposure levels (p <0.01) than the absence of such practices. There was a moderate statistical ly significant association between Al concentration and TWA(a) with total v olume of the Al/dye/water mixture using the Spearman coefficient. Time was significantly inversely proportional to the two exposure measures. The asso ciation between the two exposure measures and Al volume was not significant .