Monitoring of Peach Harvest

Peach harvest workers were evaluated for exposure to azinphosmethyl residues by measuring foliar residues, urinary alkyl phosphate metabolites, plasma and erythrocyte (RBC) cholinesterase (ChE), and dermal residues using clothing and skin washes. Workers entered orchards 51 days after application and worked in treated fields for ten of the next 17 days. Dislodgeable foliar residues ranged from 0.82-1.72 μg/cm2 and did not change significantly over the study period. Combined mean dermal exposure for the three consecutive monitoring days was 32 mg and ranged from 17.960.5 mg. Overall mean excretion levels for the five monitoring days were 1.7 mg dimethylphosphate and 1.9 mg dimethlythiophosphate. There was no significant difference in plasma ChE between the exposed harvesters and nonexposed sorters. The exposed group had significantly lower RBC ChE values than the controls for two post-exposure blood draws by three testing methods while no significant difference was found for the pre-exposure blood draw. The RBC ChE values for the post-exposure blood samples for the exposed decreased significantly about 10-20% over the three week exposure period, but increased or remained constant for the nonexposed. Urinary metabolite excretion was shown to increase with continuous exposure and was inversely correlated with both RBC and plasma ChE, but was not correlated with dermal exposure measurements. High correlations were generally observed between RBC ChE measurements taken in the field using a new spectrophotometric kit and laboratory ChE measurements.