Applicator exposure to 2,4-D, dicamba, and a dicamba isomer.

Potential respiratory and dermal exposure to applicators were estimated in a ground boom spray application of 2,4-D and dicamba. Time-weighted averages for airborne herbicide residues did not exceed 2.2 microgram/cu.m. in the cabs of application vehicles allowing only minor respiratory exposure. Dermal exposure was important as relatively large amounts of 2,4-D (1.2 - 18 mg) and dicamba (0.32-6.6 mg) were rinsed from applicators' hands. Urine analysis showed that the maximum elimination of herbicides occurred between 16 and 40 h after terminating exposure. A dicamba isomer (20% of the active material in the commercial formulation) was excreted in higher concentrations than dicamba in applicators' urine suggesting different toxicokinetic properties for the two compounds.