Monitoring of grape harvesters for evidence of cholinesterase inhibition.

This report describes the results of a long-term monitoring study of 36 grape harvesters who were occupationally exposed to organophosphate pesticide residues following reentry into vineyards during September and October 1976. The study was designed to evaluate biochemical parameters associated with organophosphate pesticide residues. Insignificant changes in blood cholinesterase activity were found. Some workers had very low levels of organophosphate metabolites in the urine during the entire 6 wk of study. Ethion dioxon was the only pesticide residue detected on the grape leaves. The harvesting of wine grapes involves numerous work crews of four to six people each, requiring a highly mobile monitoring staff. A single stationary location for collecting blood and urine samples will result in massive losses to follow-up since the workers cannot be relied on to report on their own. It is recommended that, to maximize worker cooperation, future monitoring studies rely more on analyses of urine specimens and less on venipuncture for evidence of pesticide exposure.