Agricultural Task and Exposure to Organophosphate Pesticides among Farmworkers

Article excerpt

Little is known about pesticide exposure among farmworkers, and even less is known about the exposure associated with performing specific farm tasks. Using a random sample of 213 farmworkers in 24 communities and labor camps in eastern Washington State, we examined the association between occupational task and organophosphate (OP) pesticide residues in dust and OP metabolite concentrations in urine samples of adult farmworkers and their children. The data are from a larger study that sought to test a culturally appropriate intervention to break the take-home pathway of pesticide exposure. Commonly reported farm tasks were harvesting or picking (79.2%), thinning (64.2%), loading plants or produce (42.2%), planting or transplanting (37.6%), and pruning (37.2%). Mixing, loading, or applying pesticide formulations was reported by 20% of our sample. Workers who thinned were more likely than those who did not to have detectable levels of azinphos-methyl in their house dust (92.1% vs. 72.7%; p = 0.001) and vehicle dust (92.6% vs. 76.5%; p = 0.002). Thinning was associated with higher urinary pesticide metabolite concentrations in children (91.9% detectable vs. 81.3%; p = 0.02) but not in adults. Contrary to expectation, workers who reported mixing, loading, or applying pesticide formulations had lower detectable levels of pesticide residues in their house or vehicle dust, compared with those who did not perform these job tasks, though the differences were not significant. Future research should evaluate workplace protective practices of fieldworkers and the adequacy of reentry intervals for pesticides used during thinning. Key words: applicators, farmworker, field worker, job task, occupational exposure, pesticide.


Farmworkers in various aspects of U.S. agriculture are routinely exposed to pesticides as part of their occupation. Many of these workers perform job tasks that have high risk for direct exposure to pesticides, such as mixing, loading, or applying pesticide formulations. The U.S. Environmental Protection Agency's Worker Protection Standards (U.S. EPA 1992) mandates that personal protective equipment and training be provided to these workers. Workers with direct pesticide contact are required to carry a pesticide handlers' permit or a pesticide license and, therefore, are required to receive training in the proper use and storage of pesticides and in protective measures to minimize exposure. The patterns of pesticide exposure and the effectiveness of protective measures among this group have been the topics of previous research (Alavanja et al. 1999a, 1999b; Arbuckle et al. 2002; Dosemeci et al. 2002; Garry et al. 2002a, 2002b; Gladen et al. 1998; Hoppin et al. 2002; Karr et al. 1992; Loewenherz et al. 1997; O'Fallon and Dearry 2001) and policy recommendations (cholinesterase monitoring) in recent years (Wilson et al. 1997).

The pattern of exposure is less understood among workers who perform tasks that do not require the use of personal protective equipment or safety training, such as harvesting crops, pruning vines and trees, loading or packing plants fruits and vegetables, or thinning orchards. Some of these workers may have substantial physical contact with fruits, leaves, twigs, and branches that may contain pesticide residues. Because many fieldworkers work on several crops, they may be exposed to several different types of pesticides throughout a given growing season. A limited number of previous investigations have examined workplace protective practices of this group (such as the frequency of use of gloves, long-sleeve shirts, and long pants) (Jackson 2002; Vela-Acosta et al. 2002); only a limited number have assessed pesticide exposure among this group (Fenske et al. 1999; McCurdy et al. 1994; Simcox et al. 1999).

Even less is known about the patterns of exposure of children living in households with farmworkers. A limited number of previous investigations have suggested that the children of farmworkers may experience adverse effects of pesticide exposure. …