Dermal exposure and urinary metabolite excretion in farmers repeatedly exposed to 2,4-D amine

Following multiple exposures to 2,4-D amine salts under normal field conditions in which ground rigs were used, farmers who sprayed once or twice had an average dermal exposure of 655 micrograms 2,4-D acid equivalents (a.e.)/kg a.e. sprayed and an average cumulative urinary metabolite excretion of 10.9 micrograms 2,4-D a.e./kg a.e. sprayed. One very high outlier value was excluded from these averages (F). Following 4 to 7 exposures, the average cumulative dermal exposure was 1,077 micrograms 2,4-D a.e./kg a.e. sprayed and the average cumulative urinary metabolite excretion was 21.5 micrograms 2,4-D a.e./kg a.e. sprayed. The amount of 2,4-D metabolite in urine was significantly correlated with the amount of herbicide sprayed and the time required for the urinary metabolite excretion to return to background concentration was related to the amount sprayed and the number of exposures.