Health hazards in organophosphate use among farm workers in the large-scale farming sector.

Despite rising use of pesticides in agriculture in Zimbabwe, poor monitoring and lack of community-based assessment implies that there is little documentation of the extent and nature of poisoning in the agricultural working class. The paper presents the results of a longitudinal study of exposure to organophosphates in twelve farms in Mashonaland Central during the 1985/6 spraying season. Significant reductions in cholinesterase activity were observed in the group of workers spraying pesticides during the spraying season compared to non-spraying controls in the same period. State farms had significantly lower levels of exposure than private farms. Reductions in cholinesterase activity did not correspond with reported symptoms, given the non-specific nature of these symptoms. Levels of protective clothing, of knowledge of correct practice of pesticide use and of associated hazards was found to be low in users. Regular monitoring of workers using toxic pesticides is recommended.