Pesticides that are used extensively in U.S. agriculture include such compounds as insecticides, herbicides, defoliants, molluscicides, nematocides, algicides, and acaricides (Shaver and Tong, 1991). Pesticides may be absorbed into the body through the skin, by inhalation, and by ingestion. Agricultural workers can experience exposure through these routes in a variety of ways. In addition to the exposure that occurs during the processes of diluting, mixing, and applying the substances, workers can be exposed to drifting chemicals from cropdusting, and can come into contact with residues during harvesting, weeding, and pruning and while eating in the field. Water may become contaminated and then be used for drinking, bathing, and cooking. Particularly hazardous are labor-intensive crops, such as fruits and vegetables, which are extensively treated with pesticides.
Pesticides have been associated with a number of delayed health effects, such as chronic dermatitis, fatigue, headaches, sleep disturbances, anxiety, memory problems, and different kinds of cancers, birth defects, sterility, blood disorders, and abnormalities in liver and kidney function, chronic neurotoxicity, and adverse reproductive consequences (Moses, 1989; Sharp et al., 1986; Wasserstrom and Wiles, 1985). Estimates of the occurrence of pesticide-related illnesses are difficult to make because underreporting is likely: Many migrant farmworkers who might be affected never see physicians or are never properly diagnosed; if the workers do seek medical attention, the health-care professionals may be unfamiliar with the symptoms of pesticide-related illnesses, and farmworkers may not know the names of the pesticides being used. Although relatively new regulations require workers to be informed if a field is to be sprayed, there is no information as to how well the warning procedure is being followed. In addition, there is relatively little information on the effects on children and adolescents of exposure to pesticides and whether they should stay out of sprayed fields longer than adults.
This section relies heavily on Mobed et al. (1992).