Biomarkers of Pesticide Exposure: Adult and Adolescent Farmworker Comparisons

Abstract

SM1-PD-10 Agricultural workers may be exposed to pesticide spray, drift, and residues on plants; however, little evidence is available on acceptable levels of pesticide exposure in this population. It has been suggested that developmental factors (physical, cognitive, and psychologic) may place youth workers at increased risk for occupational illness and injury, including the potential for pesticide exposure. We conducted an investigation of 133 hispanic farmworkers and 56 appropriate controls and assessed whether short-term biomarkers of exposure to pesticides (including insecticides and fungicides) differed in adolescents employed in agriculture compared with adult farmworkers, controlling for type of agricultural work, hours worked, and reported hygiene practices. All agricultural workers were employed in crop harvesting and were recruited from agricultural temporary housing and from evening and school year ESL programs. The mean age of the adult workers was 29 years with a mean of 9.3 years of agricultural work and average age of the adolescent workers was 15.3 years with an mean of 3.0 years of agricultural work. Surveys were administered on work histories and work practices and included questions on type of work activity, pesticide application, type of crop(s), work hours per week, use of protective clothing, bathing, and laundry practices. A spot urine sample was collected for the measurement of pesticide urinary biomarkers. Urinary samples were analyzed for alkylphosphate metabolites from organophosphates and for the metabolite of Captan (tetrahydrophthalimide; THPI), a fungicide frequently used on berry crops. All pesticide metabolite levels were adjusted for urinary creatinine concentration. Levels of THPI were were shifted significantly higher in the total agricultural when compared with controls. We found that median levels of the major OP metabolite (DMTP) among teen farmworkers was slightly higher compared with adult workers, although not statistically higher (3.2 ng/mL vs. 1.1 ng/mL). A similar, but nonsignificant trend was observed for THPI (0.073 μg/mL vs. 0.025 μg/mL). Our previous studies have found that adolescent farmworkers are less knowledgeable about pesticide safety, but protective practices did not differ significantly from those of adults. These results indicate that exposure levels among these 2 populations do not differ; and while these results are reassuring, they cannot be generalized to all crops in which adolescents work. Future analyses will examine differences in markers of potential health effects in adolescent farmworkers compared with adults with comparable levels of pesticide exposure.