PFAS in Pesticides Could Pose a Greater Multigenerational Threat Than DDT

‘Forever’ Pesticides Threaten Worse Environmental Harms Than DDT

By Nathan Donley & Kyla Bennett

When the U.S. Environmental Protection Agency ended most uses of the notorious pesticide DDT back in 1972, it wasn’t just because of the poison’s then suspected links to cancer and serious reproductive effects in humans. Evidence also suggested that the chemical would bioaccumulate in living things and persist in the environment for centuries, threatening the health of our children, our children’s children and beyond—a disturbing reality confirmed by recent research.

Now, more than 50 years later, a growing body of research reveals the EPA is failing to fully address a similar, and potentially even greater, multigenerational chemical threat: the skyrocketing presence of perfluoroalkyl and polyfluoroalkyl substances (PFAS), aptly dubbed “forever chemicals,” in millions of gallons of pesticide products that are widely used across the U.S. PFAS contain chemical bonds that are extremely hard to break, making them difficult to get rid of once they are released into the world. PFAS contamination has been documented in hundreds of species of wildlife from the far reaches of the Arctic to the tropics in the Pacific Ocean. Very low concentrations of many PFAS have been linked to certain cancers, delays in childhood development and immune system dysfunction in humans. Earlier this year the EPA set drinking water regulations for six PFAS, with permissible levels in the excruciatingly minuscule “parts per trillion” range.When PFAS are present in pesticide products, many of which are sprayed on food crops and run off into nearby waterways, people can be exposed by eating contaminated food and drinking contaminated water.

In a newly published study, we and our colleagues from several environmental watchdog groups identified troubling gaps in the EPA’s pesticide approval process that have resulted in the agency failing to fully assess the harms from the growing number of these forever chemicals added to many pesticides. The implications of that glaring lapse could not be more dire. The gaps in pesticide safety oversight—including waiving immunotoxicity studies for pesticide active ingredients, not fully accounting for the partial transformation of pesticides into different chemicals over time and failing to assess the cumulative toxicity of PFAS pesticide use—must be rectified moving forward.

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Around one billion pounds of pesticide products are used each year across hundreds of millions of acres of U.S. farmland, making pesticides some of the nation’s most widely distributed pollutants. Simply put, if the goal was to spread forever chemicals as broadly as possible across the nation, there would likely be no more efficient way of doing so than putting them in pesticides.

Our study found that 14 percent of all conventional active ingredients in pesticides are PFAS. Worse yet, the long-lived chemicals comprise 30 percent of pesticide active ingredients approved in just the past 10 years, meaning that pesticide contamination with PFAS is trending upward and will likely increase in the coming years.

Although PFAS are known to leach from plastic storage containers into pesticides, contamination is more often the result of pesticide ingredients that are forever chemicals in their own right. PFAS pesticide ingredients and their “degradates”—what they turn into after partially breaking down—can stick around for decades or centuries and are incredibly potent. But the more potent and persistent the poison, the more likely it is to cause collateral damage.

The trend is clear: pesticide manufacturers are increasingly in the business of making “forever pesticides.” According to estimates by the U.S. Geological Survey, the nation annually uses 23 million to 35 million pounds of pesticide ingredients that are PFAS.

Yet what happens to those increasing loads of forever chemicals once they are sprayed on fields is not well understood. The little we do know is extremely troubling: although only about 20 percent of PFAS pesticides have been monitored in U.S. waterways, federal regulators have found nearly all of them in rivers and streams across the nation.

The increasing “PFASification” of pesticides and the resulting environmental contamination are partly the result of regulations that seek to mitigate immediate toxicity concerns without fully accounting for the length of time a chemical will persist in the environment or for the effects of its degradates.

Many researchers now believe that beyond a substance’s overt toxicities, its persistence alone should be a basis for its regulation, because any release of the substance into the environment will likely be irreversible. And as our understanding of PFAS toxicity grows over time, we have found these chemicals are often more harmful than previously thought.

Right now, with summer coming to an end in the U.S., many farmers have already applied pesticides to try to suppress weeds, insects or fungi. That means tens of millions of pounds of forever chemicals were added to the environment this year alone and will remain there, in one form or another, for the birth of your grandchildren’s grandchildren and generations thereafter.

It’s hard to imagine a more frightening indictment of the chemical-intensive agriculture that has been allowed to evolve in this country. But farmers are not the problem here. By not accounting for effects that will be realized decades or even centuries from now, EPA regulators are enabling this type of harmful agriculture.

The only reason the EPA was able to ban incredibly persistent chemicals such as DDT and PCBs in the 1970s was because the agency acknowledged their long-term harm to society and the environment and faced, full-on, the difficult task of navigating the political challenges inherent in banning any widely used pesticide product.

The agency tasked with the job of protecting our health and the environment must pivot and fully embrace its duty to reverse the fast-emerging threat posed by PFAS.

If the EPA fails to face this challenge, it will be responsible for burdening generations to come with increases in deadly, chronic diseases and toxic cleanup responsibilities that will, quite literally, last forever.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.