A recent research study revealed that 22% of adults and 10% of children involved in an air-quality assessment in California’s San Joaquin Valley were exposed to measurable levels of pesticides. This includes chlorpyrifos, a pesticide that is no longer allowed in California.
New research conducted by UC Davis Health discovered that among participants in an air-quality study in California’s San Joaquin Valley, 22% of adults and 10% of children were found to be inhaling levels of pesticides that could be detected. This includes chlorpyrifos, which is banned in California.
The findings have been published in the Journal of Exposure Science and Environmental Epidemiology.
Deborah H. Bennett, the lead author and a professor of environmental health at UC Davis School of Medicine’s Department of Public Health Sciences, commented, “Although our study involved a small group, the results are important. They indicate that both children and adults in agricultural areas of the San Joaquin Valley continue to face exposure to pesticides and herbicides, even with ongoing efforts to limit their use.”
California is an agricultural powerhouse, utilizing millions of pounds of chemical pesticides each year.
Data from the California Department of Pesticide Regulation shows that in 2022, five out of the six counties using the highest amounts of pesticides were located in the San Joaquin Valley, namely Fresno, Kern, Tulare, San Joaquin, and Madera counties.
Backpack sensors collected air samples
The researchers enlisted 31 adults and 11 children from three small agricultural towns in the San Joaquin Valley. The participants were outfitted with backpacks that featured special air-collection tubes attached to the straps. This setup enabled researchers to gather samples from the air the participants were inhaling.
Each participant wore the backpacks for periods ranging from 1 to 3 days, with daily usage lasting between eight to 14 hours. Collectively, air samples were obtained over a total of 92 days.
Upon analysis, the researchers discovered that seven adults (22% of adult participants) and one child of school age were breathing air that contained detectable levels of at least one pesticide.
The air samples contained various pesticides, including:
- 1,3-dichloropropene, a pesticide utilized for eliminating parasitic worms
- Chlorpyrifos, a long-used pesticide that has been associated with neurological damage in children
- Pyrimethanil, a fungicide aimed at preventing mold and mildew growth
- Another insecticide intended to keep insects at bay
- Penthiopyrad, a fungicide that helps in stopping mold and mildew
- Trifluralin, an herbicide designed to manage grasses and weeds
At the time of sampling, chlorpyrifos was no longer approved for use in California. Previous studies have shown that chlorpyrifos can cause various harmful health effects, especially as a developmental neurotoxin for children and other vulnerable groups.
While the dangers of chemicals like chlorpyrifos are well-documented, many other compounds remain under-researched. For example, studies using zebrafish revealed that penthiopyrad exposure led to developmental deformities, but similar research has yet to be conducted on mammals, leaving its effects on humans unclear.
“It’s crucial to enhance our community’s monitoring of chemicals routinely used in agriculture,” said Bennett. “We also require new studies to assess the potential toxicity of substances that people frequently encounter in California’s farming communities.”
Participants in this study acted as citizen scientists, going about their everyday activities while wearing the backpacks to gather air samples.
Jane Sellen from Californians for Pesticide Reform, who co-authored the study, stated, “Many agricultural community members are very concerned about pesticide exposure. They were eager to assist scientists in gathering this crucial data. Even with a limited sample size, the findings were alarming but not unexpected.”
Co-authors Rebecca Moran, Christopher P. Alaimo, and Thomas M. Young from UC Davis contributed to the study as well.
The project received funding from the California Air Resources Board Community Air Grant (19-CAUP-11) and the National Institute of Environmental Health Sciences (2P30 ES023513).
