Toxic ‘forever chemicals’ found in pesticides used on food, in homes and on pets, study finds
Present in the blood of an estimated 98% of Americans, the hormone-disrupting chemicals are so worrisome that in July 2022 the National Academies of Sciences, Engineering, and Medicine set “nanogram” levels of concern and called for testing of high-risk individuals, including infants and older adults.
In April, the US Environmental Protection Agency announced historic rules designed to strictly control levels of five of the most studied PFAS in the nation’s drinking water, one of the routes of human exposure. Contamination can also come from the presence of PFAS in food packaging, stain-resistant textiles and thousands of consumer products such as cookware, tampons and cosmetics.
However, a new study takes a closer look at yet another, little studied avenue of possible exposure — the existence of PFAS in pesticides used in both agricultural and residential pest control, including pet flea treatments.
“This is really the first study in the US to comprehensively look at how pesticides can be contributing to global PFAS contamination,” said Alexis Temkin, coauthor of the study published Wednesday in the journal Environmental Health Perspectives. She is senior toxicologist for the Environmental Working Group, or EWG, an environmental and health advocacy organization based in Washington, DC.
Food staples such as apples, corn, kale, spinach, strawberries and wheat are frequently sprayed with PFAS-containing pesticides, said coauthor David Andrews, a senior scientist and deputy director of investigations at the Environmental Working Group.
“These pesticides are applied to tens of millions of farm fields across the United States in quite high quantities, and they are contributing to PFAS contamination,” Andrews said. “The use of these pesticides may also partially explain some of the unidentified PFAS contamination that scientists see occurring in our waterways.”
The PFAS pesticides are also used in flea treatments for pets and insect-killing sprays in homes, according to the research conducted by scientists at EWG, the Center for Biological Diversity in Tucson, Arizona, and Public Employees for Environmental Responsibility in Silver Spring, Maryland.
“One pesticide listed in (the paper) was fipronil. This is in specific flea/tick products that can be applied to pets! I didn’t know that this was a PFAS,”said environmental toxicologist Dr. Jamie DeWitt, director of Oregon State University’s Pacific Northwest Center for Translational Environmental Health Research, in an email.
“The study provides empirical evidence of the extent of PFAS in pesticides,” said DeWitt, who was not involved in the research.
More oversight needed
Despite the presence of PFAS, the chemicals are not often considered in federal pesticide regulatory efforts or in toxicologic evaluations of pesticides, said Stephanie Eick, an environmental and reproductive epidemiologist and assistant professor at Emory University in Atlanta. She too was not involved with the new study.
“The regulations surrounding pesticides are currently outdated and ineffective, so this discovery of PFAS presence in pesticide formulations represents a new opportunity for the US EPA to improve the scientific validity of pesticide risk assessment to better capture real-world exposure scenarios,” said Eick in a commentary published with the study.
As it has with other scientific contributions, the Environmental Protection Agency will review the new report and remains “committed to addressing the risks from PFAS from all sources, including pesticides,” an EPA spokesperson told CNN via email.
In addition, the EPA has taken “significant steps” in recent years to understand and address PFAS in pesticides, including the removal of 12 PFAS ingredients from pesticide manufacturing, the spokesperson added.
The American Chemistry Council, an industry association, told CNN that pesticides are among the most stringently regulated products in the United States.
“We would need time to review closely, but it appears these researchers are lumping many pesticides in as PFAS that are not,” said Tom Flanagin, senior director of product communications for ACC.
While farm workers and others who work with or near pesticides are at highest risk, pesticide exposure is widespread. Over 90% of the US population has detectable amounts of pesticide in their urine or blood, according to estimates.
PFAS helps pesticides last longer
The study authors submitted Freedom of Information requests to various state and federal government agencies in the US, including the EPA.
The analysis found 66, or 14%, of all active ingredients in pesticides are PFAS, which are intentionally added to improve the product’s ability to eliminate pests, Andrews said.
“They add PFAS components to pesticides because it also increases the stability of the pesticide in the fields,” he said. “The pesticide is less likely to be broken down as quickly, and so it can stay effective for a longer period of time without reapplication.”
Pesticides also contain inert ingredients, which do not kill pests but are added as the “carrier of the active ingredient, such as a capsule carrying a pharmaceutical,” said Rainer Lohmann, a professor at the University of Rhode Island’s Graduate School of Oceanography who studies sources of PFAS. He was not involved with the study.
Inert ingredients do not have to be disclosed on the product’s label, Andrews said. The analysis found eight EPA-approved inert ingredients were PFAS, including the nonstick chemical Teflon. In February, the EPA proposed the removal of Teflon in pesticide products.
The analysis also found nearly one-third of new ingredients approved by federal agencies for use in pesticides in the past decade contained PFAS, likely due to the longevity and other benefits, Temkinsaid.
“The registration of pesticides that need PFAS is increasing,” she said. “This seems to be a trend.”
PFAS-creating containers
Another unusual source for PFAS comes from the pesticide containers themselves as a result of a chemical reaction, Andrews said.
“Fluorine gas is put into a plastic container, and the fluorine reacts with the surface to make it more stable,” he said. “The EPA has found that reaction creates byproducts — long-chain PFAS such as PFOA and PFOS, which have been banned.”
An estimated 20% to 30% of the plastic containers that contain pesticides and fertilizers are fluorinated and can leach PFAS into the contents, according to the paper.
After first learning in 2020 about possible PFAS contamination in fluorinated plastic pesticide containers, the EPA has developed new ways to detect PFAS at low levels in pesticide containers and products, a spokesperson said.
“The chemical reaction is not just restricted to pesticide containers,” Andrews said. “It applies to some fragrance and other consumer product containers. It’s a big issue that extends beyond pesticides and may be an important contributor to how the concerning long-chainPFAS are remaining in the environment.”
Long-chain PFAS chemicals perfluorooctane sulfonic acid, or PFOS, and perfluorooctanoic acid, or PFOA, are among the most studied of the nearly 15,000 types of PFAS used by industry. Both chemicals have been linked to heightened risk of serious health problems such as cancer, obesity, thyroid disease, high cholesterol, decreased fertility, liver damageand hormone disruption, according to the EPA.
“These are hidden sources of PFAS that are an underappreciated source of contamination of our waterways, the environment and potentially our bodies,” Andrews said.
Just how significant are these exposures? More research is needed, experts say. However, the paper makes “a good case that fluorinated pesticide compounds contribute a large share to unrecognized PFAS out there and seem to have a much larger contribution than expected previously,” DeWitt said.
“(This research) verifies that PFAS are part of pesticidal products either as an active ingredient of the pesticide or as a contaminant introduced from the pesticide packaging,” he said.
The study suggests that food staples like apples, corn, and strawberries are frequently sprayed with PFAS-containing pesticides, contributing to their contamination in the food chain. According to Stephanie Eick, the regulations surrounding pesticides are outdated and ineffective, providing an opportunity for the Environmental Protection Agency to improve risk assessment and better capture real-world exposure scenarios.
