Scientists are alarmed by the presence of toxic substances in pesticides
A new study has shown that toxic «forever chemicals» are contained in pesticides used in food, at home and for treating pets.
Perfluoroalkyl and polyfluoroalkyl substances (PFAS), called «forever chemicals» because of how long they last in the human body and the environment, are a growing public health concern, CNN reports.
With the hormone-disrupting chemicals in the blood of about 98% of Americans, they are so alarming that in July 2022, the National Academies of Sciences, Engineering, and Medicine set a «nanogram» level of concern and called for testing of high-risk individuals, including infants and the elderly.
In April, the U.S. Environmental Protection Agency announced historic rules aimed at strict controls on five of the most studied PFAS in the nation's drinking water, which is one route of human exposure. Contamination can also be caused by PFAS in food packaging, stain-resistant textiles, and thousands of consumer products such as cookware, tampons, and cosmetics.
But the new study takes a closer look at another, little-studied route of possible exposure: the presence of PFAS in pesticides used both in agriculture and in homes to control pests, including flea repellents.
“This is really the first study in the U.S. to comprehensively examine how pesticides may contribute to global PFAS contamination,” said Alexis Temkin, a co-author of the study published Wednesday in the journal Environmental Health Perspectives. She is a senior toxicologist at the Environmental Working Group, or EWG, an environmental health advocacy organization based in Washington, D.C.
Food staples such as apples, corn, kale, spinach, strawberries and wheat are often treated with pesticides containing PFAS, said co-author David Andrews, a senior scientist and associate director of research at the Environmental Working Group.
«These pesticides are applied to tens of millions of agricultural fields across the United States in fairly large quantities, and they contribute to PFAS contamination,» Andrews said. «The use of these pesticides may also partially explain some of the unidentified PFAS contamination that scientists are seeing in our waterways.»
PFAS pesticides are also used to treat pets for fleas and in sprays to kill insects in homes, according to research by scientists at EWG, the Center for Biological Diversity in Tucson, Arizona, and state environmental officials in Silver Spring, Maryland.
“One of the pesticides listed in the article was fipronil. It's in flea and tick repellents that you can use on pets! I didn't know it was a PFAS,” environmental toxicologist Dr. Jamie DeWitt, director of Oregon State University's Pacific Northwest Center for Translational Environmental Health, wrote in an email.
“The study provides empirical evidence of PFAS in pesticides,” said DeWitt, who was not involved in the study.
Despite their presence, PFAS are not often considered in federal pesticide regulations or toxicological assessments of pesticides, said Stephanie Eich, an environmental and reproductive epidemiologist and associate professor at Emory University in Atlanta. She was not involved in the new study.
“Pesticide regulations are currently outdated and ineffective, so the discovery of PFAS in pesticide formulations represents a new opportunity for EPA to improve the scientific basis for pesticide risk assessments to better account for real-world exposure scenarios,” Eich said in a commentary published with the study.
As with other scientific work, the EPA will review the new report and remains «committed to addressing the risks of PFAS from all sources, including pesticides,» an EPA spokesperson told CNN in an email.
Additionally, the EPA has taken «significant steps» in recent years to understand and eliminate PFAS in pesticides, including removing 12 PFAS components from pesticide manufacturing, the spokesman added.
The American Chemistry Council, an industry association, told CNN that pesticides are among the most highly regulated products in the United States.
«It will take time for us to do a thorough review, but it appears that these researchers are classifying a lot of pesticides as PFAS that are not,» said Tom Flanagin, senior director of product communications for the ACC.
While farm workers and others who work with or near pesticides are at greatest risk, pesticide exposure is widespread. It is estimated that more than 90% of the U.S. population detects some level of pesticides in their urine or blood.
The study authors submitted freedom of information requests to various state and federal government agencies, including the Environmental Protection Agency.
According to Andrews, the analysis found that 66, or 14%, of all pesticide active ingredients are PFAS, which are intentionally added to improve the product's ability to kill pests.
“They add PFAS ingredients to pesticides because it also improves the stability of the pesticide in the fields, he said. — The pesticide is less likely to break down as quickly, so it can remain effective for a longer period of time without re-application.
Pesticides also contain inert ingredients that don't kill pests but are added as a «carrier for the active ingredient, like a drug capsule,» says Rainer Lohmann, a professor at the University of Rhode Island's Graduate School of Oceanography who studies the sources of PFAS. He was not involved in the study.
Inert ingredients don’t have to be listed on a product label, Andrews said. The analysis found that eight EPA-approved inert ingredients were PFAS, including the nonstick chemical Teflon. In February, the EPA proposed eliminating Teflon from pesticide products.
The analysis also found that nearly a third of new ingredients approved by federal agencies for use in pesticides over the past decade contained PFAS, likely because of durability and other benefits, Temkin said.
“The number of pesticides that require PFAS is growing,” she said. “It seems to be a trend.”
Another unusual source of PFAS is the pesticide containers themselves, which are the result of a chemical reaction, Andrews said.
«Fluorine gas is put into a plastic container, and the fluorine reacts with the surface, making it more stable,» he said. «The EPA has found that the reaction produces byproducts called long-chain PFCs, such as PFOA and PFOS, which have been banned.»
An estimated 20% to 30% of plastic containers containing pesticides and fertilizers contain fluoride, which can cause PFAS to leach out of the contents.
After potential PFAS contamination in fluorinated plastic pesticide containers first became known in 2020, the EPA developed new ways to detect PFAS at low levels in pesticide containers and products, an EPA spokesperson said.
«The chemical reaction is not limited to pesticide containers,» Andrews said. «It's also present in some perfume and other consumer product containers. It's a serious issue that goes beyond pesticides and may be an important factor in how the relevant long-chain PFCs persist in the environment.»
Perfluorooctane sulfonic acid, or PFOS, and perfluorooctanoic acid, or PFOA, are among the most studied of the nearly 15,000 types of PFAS used in industry, CNN reports. Both chemicals have been linked to increased risks of serious health problems like cancer, obesity, thyroid disease, high cholesterol, decreased fertility, liver damage, and hormonal disruption, according to the EPA.
“These are hidden sources of PFAS that are an underappreciated source of contamination in our waterways, our environment, and potentially our bodies,” Andrews says.
How significant are these exposures? More research is needed, experts say. Still, the paper provides «compelling evidence that fluorinated pesticide compounds are significant contributors to unrecognized PFAS and appear to be much larger contributors than previously expected,» DeWitt said.
«This study confirms that PFAS are present in pesticide products, either as an active ingredient in the pesticide or as a contaminant contained in the pesticide packaging,» he said.
Свежие комментарии