Exposure of professional pesticide applicators to carbaryl

Dermal and respiratory exposure, and erythrocyte and serum acetylcholinesterase activity were monitored on two groups of professional pesticide applicators spraying trees with carbaryl. The mean dermal exposure to the first group was 128 mg hr-1 of carbaryl and the mean respiratory exposure was 0.1 mg hr-1. The maximum percent (%) toxic dose received by the applicators was 0.12% hr-1. The mean exposure to the second group of applicators was 59.4 mg hr-1 dermal and 0.1 mg hr-1 respiratory, for a total of 0.02% toxic dose per hr. It was estimated that 86.9% of the dermal exposure was to the forearms and hands. The rate of exposure to pads placed under the applicators clothing was approximately 1/20 that of pads on the outside of the clothing. Of the body areas monitored, the back received the least rate of exposure. It was determined, in vitro, that 10(-3) M carbaryl would inhibit human serum (pseudocholinesterase) and erythrocyte acetylcholinesterase for at least 72 hr. There was no overall inhibition of acetylcholinesterase activity in the applicators.