Bringing Work Home: Take-Home Pesticide Exposure Among Farm Families

Abstract

In this thesis take-home pesticide exposure among farm families, with an emphasis on herbicides, was investigated. Take-home exposure occurs when a worker unwittingly brings home a substance on his or her clothing or shoes, thereby potentially exposing his or her family. The pesticides investigated were atrazine, metolachlor, acetochlor, alachlor, 2,4-D, glyphosate, and chlorpyrifos; all were applied to either corn or soybean crops. A questionnaire was administered to each family to determine pesticide use and work practices. Urine samples were collected from the participants and dust, wipe and air samples were collected from each home. Atrazine was the agricultural pesticide used most by farmers and more than one agricultural pesticide was applied on most farms. Most farmers changed from their work clothes and shoes in the home, and when they changed outside they usually brought their clothes and shoes inside. Greater than 88% of the air and 74% of the wipe samples were below the limit of detection (LOD). Among the air and wipe samples, chlorpyrifos was detected most frequently in homes. In the dust samples, all the pesticides were detected in greater than 50% of the samples except acetochlor and alachlor, which were detected in less than 30% of the samples. Pesticides in dust samples were detected more often in farm homes except 2,4-D, which was detected in 100 percent of the farm and non-farm home samples. All farms where a pesticide was sprayed had higher levels of that pesticide in dust than both farms that did not spray that pesticide and non-farms, however, only atrazine and metolachlor were significantly higher. For atrazine, acetochlor, metolachlor and 2,4-D, farmers who reported applying the pesticide had significantly higher urinary metabolite levels than non-farmers, farmers who did not apply the pesticide, and farmers who had the pesticide commercially applied. The adjusted geometric mean (GM) level of the urine metabolite of atrazine was significantly higher in fathers, mothers and children from farm households compared to those from non-farm households. Urine metabolites of chlorpyrifos were significantly higher in farm fathers and marginally higher in farm mothers when compared to non-farm fathers and mothers, but metolachlor and glyphosate levels were similar between the two groups. Farm children had significantly higher urinary atrazine and chlorpyrifos levels (p = 0.03 and p = 0.03 respectively) when these pesticides were applied by their fathers prior to sample collection than those of farm children where these pesticides were not recently applied. Estimated doses for the children were calculated for atrazine, metolachlor, chlorpyrifos and glyphosate from urinary concentrations. For all pesticides except glyphosate, the doses from farm children were higher than doses from the non-farm children. The difference was statistically significant for atrazine but only marginally significant for chlorpyrifos and metolachlor. None of the doses exceeded the U.S. Environmental Protection Agency (EPA) chronic reference values for atrazine, metolachlor and glyphosate; however, all of the doses for chlorpyrifos exceeded the EPA chronic population adjusted reference value. The results show that farm homes are contaminated with pesticides and exposure of inhabitants is occurring.