By: Richard Fenske
In the late 1980s, studies of children’s exposures to hazardous chemicals, aside from lead, were sparse. Medical reports from emergency rooms and a handful of air sampling studies were the primary scientific literature available for children and pesticides. The U.S. EPA began to push pesticide registrants to produce exposure data directly applicable to children. Several American Chemical Society symposia focused on this topic (this was pre-ISES). But, of course, intentional exposure of children was unethical, and children weren’t workers – the source of most pesticide exposure data at the time – so simple models were constructed, pretty much on assumptions and educated guesses, given the absence of data. I recall one rep of a pesticide manufacturer throwing out suggestions based on having watched his grandchild play for 15 minutes. The path forward was clear. In the absence of data, collect data. My students and I at Rutgers University developed a hypothetical exposure scenario involving a crawling infant in an apartment treated for fleas with chlorpyrifos. We had a licensed pest control operator apply the pesticide according to label in a vacant, carpeted apartment, and we then collected deposition samples, wipe samples and air samples, allowing us to construct a rudimentary risk assessment that including both the dermal and respiratory routes. The estimated risk was of enough concern that at least one state banned chlorpyrifos for residential flea treatment.
At the University of Washington, I learned that many hundreds of children were being exposed routinely to pesticides in the agricultural regions of the State. We conducted our first study of pesticide exposure among farm worker children in 1992. In an EPA-funded study led by Nancy Simcox we sampled soil and house dust for multiple organophosphorus (OP) pesticides in the tree fruit region around Wenatchee (“The Apple Capital of the World”). An interesting side note: we collected house dust with the newly developed High Volume Sampler (HVS-3). John Roberts, who designed the HVS-3, had been working with EPA to sample lead in house dust. He lived in Seattle and was happy to lend us his novel device.
We demonstrated that pesticide levels in soil decreased quickly after spraying, but pesticides levels found in the house dust of worker homes were elevated and appeared to accumulate over time. We probably induced more than one heart attack when we presented our results to the leaders of the tree fruit industry. Their responses ranged from “too low to cause any harm” to “not our problem” or words to that effect. But they did start thinking about children’s health, especially their own children, many of whom lived amidst the orchards.
This 1992 study stimulated new research focused on children’s pesticide exposures, and likely contributed to the decision by NIEHS to create children’s environmental health centers in 1998 – with two of eight centers focused on OP pesticide exposures of children in agricultural communities.
Fenske et al. (1990) Potential exposure and health risks of infants following indoor residential pesticide applications. Am J Publ Health 80:689-693.
Simcox N et al. (1995) Pesticides in Household Dust and Soil: Exposure Pathways for Children of Agricultural Families. Environ Health Perspect 103(12):1126-34.
Roberts JW et. al. (1991) Development and field testing of a high volume sampler for pesticides and toxics in dust. J Expo Anal Environ Epidemiol Apr;1(2):143-55