Evaluation of Dermal Exposure to the Herbicide Alachlor Among Vegetable Farmers in Thailand

Abstract

Vegetable farmers applying the herbicide alachlor may be highly exposed through dermal contact when spraying. Dermal patches were attached to 10 locations on the farmers' skin when they mixed and applied alachlor in vegetable farming areas in Thailand. Measurements were made on farmers using either a backpack sprayer with a 2 stroke gasoline motor and fan or a battery operated pump. Forty-seven vegetable farmers in Bungphra subdistrict of Thailand participated in this study. Both motorized and battery pump backpack sprayers wearing long-sleeve shirts had significantly lower alachlor concentrations on the dermal patches under their long-sleeve shirts compared to those who wore only short-sleeve shirts, regardless of the sprayer type. Moreover, sprayers wearing long pants had significantly lower alachlor concentrations on dermal patches placed under the pants on the lower legs than those wearing short pants, regardless of the sprayer type. The highest estimated alachlor exposures were found on the upper legs (median = 9.29 µg/h) for those using a 2 stroke engine/fan backpack sprayer and on the lower legs (2.87 µg/h) for those using the battery operated pump backpack sprayer. The estimated total body alachlor exposures of applicators using the 2 stroke engine/fan backpack sprayer (219.48 µg/h) were significantly higher than those using the battery operated pump backpack sprayer (15.50 µg/h). Using long-sleeve shirts as personal protection reduced alachlor exposures for the arms 97–99% and wearing long pants reduced alachlor exposure to the legs for 81–99%. Thus, training about the protection provided by clothing choices would be one step in improving the health and safety of Thai farmers.