EPA to Study Microplastics, Medications in Drinking Water (1)

The EPA is proposing to investigate whether microplastics and pharmaceuticals in drinking water puts the public’s health at risk, while its sister health agency launches a multimillion effort to measure, understand their health effects, and remove microplastics from the human body.

The Environmental Protection Agency’s proposal is the first step in a process it uses to decide if the substances need to be regulated, but it stops short of requiring water utilities to monitor the extent of microplastics and medicines in drinking water.

“For too long, Americans have vocalized concerns about plastics and pharmaceuticals in their drinking water. That ends today,” EPA Administrator Lee Zeldin said in a statement Thursday.  Zeldin announced the EPA’s proposed sixth Contaminant Candidate List (CCL 6), a list of unregulated substances known to be in drinking water.

“By placing microplastics and pharmaceuticals on the Contaminant Candidate List for the first time ever, EPA is sending a clear message: we will follow the science, we will pursue answers, and we will hold ourselves to the highest standards to protect the health of every American family,” he said.

Publishing the CCL does not impose any requirements on public water systems. Instead, the agency would compile health effects and other information about the substances to determine if further actions, like mandated monitoring by water utilities, would be needed.

Department of Health and Human Services Secretary Robert F. Kennedy Jr. announced a $144 million Systematic Targeting Of MicroPlastics, or STOMP, research initiative to find ways to detect microplastics in the human body, figure out how and where they move, and ultimately remove them.

The research is essential as scientists estimate food, water, and the air bring tens of thousands of microplastic particles into the human body, where they pass into babies’ bodies before they’re born, Kennedy said Thursday. One study also found roughly a spoonful of the particles in the brain, he said.

Pharmaceutical Screening Levels

Pharmaceuticals the EPA would examine include antidepressants, hormones, antibiotics, and other drugs, the EPA said.

The agency also is proposing human health benchmarks—nonenforceable screening levels that indicate potential risk—for 374 pharmaceuticals. That information will give states, tribes, and local water systems a new tool to assess risk and take action when drug residues are found at concerning levels, the agency said.

The other substances the EPA will propose to add to the CCL are per- and polyfluoroalkyl substances (PFAS), disinfection byproducts, 75 individual chemicals, and nine microbes.

The agency’s proposed action doesn’t meet requests by seven governors and 176 nonprofit organizations for the EPA to add microplastics to the sixth Unregulated Contaminant Monitoring Rule (UCMR 6). That move would require public water systems to test drinking water to determine the extent to which it contains designated substances.

The EPA’s proposed UCMR 6 is currently under review by the White House’s Office of Information and Regulatory Affairs, which determines whether it can be released.

Contaminants the agency has considered for that rule include dicamba, a pesticide; triclosan, an antibacterial chemical; and 1,2,4-trimethylbenzene, a sterilizing agent that’s also used to make dyes, perfumes, and resins.

‘Collect Monitoring Data’

Adding microplastics to the CCL is a good step, “but it’s not enough on its own. We need the EPA to start collecting the monitoring data,” said Mary Grant, who directs Food & Water Watch’s Public Water for All campaign.

If microplastics aren’t added to the UCMR 6, it’ll be 10 years before the EPA could start getting monitoring data, and that’s only if the agency adds the chemicals to the next monitoring rule, she said.

Meanwhile, scientific studies are finding the tiny particles of plastic in the liver, colon, lungs, placenta, and testes, among other places, she said.

Health concerns researchers have flagged include gastrointestinal, liver, and reproductive problems, along with cell and tissue damage, neurodevelopmental effects, and cancer, Grant said.

The American Chemistry Council supports science-driven monitoring of microplastics in drinking water and research to better understand potential impacts, said Kimberly Wise White, vice president of regulatory and scientific affairs, in a statement.

But, any drinking water monitoring program must address existing hurdles, including developing clear definitions, ensuring adequate lab capacity, and standardizing sampling and testing methods to be used consistently across the country, she said.

ACC called on Congress to pass the Plastic Health Research Act (H.R. 4903) to coordinate federal research.

The public will have 60 days to comment on the EPA’s proposal, which also will be critiqued by the agency’s independent Science Advisory Board. The agency expects to publish a final list by Nov. 17, 2026.