Federal EPA Lists Microplastics and Pharmaceuticals as Priority Drinking Water Contaminants

WASHINGTON — The Environmental Protection Agency announced Thursday that it will add microplastics and pharmaceuticals to a list of drinking water pollutants that may be regulated in the future, prompting a mix of praise and criticism in Michigan and across the country.

EPA Administrator Lee Zeldin said the announcement stops short of requiring monitoring of the chemicals' presence in water systems — something Gov. Gretchen Whitmer and a host of environmental groups have urged. But listing the pollutants as priority contaminants under the Safe Drinking Water Act will prioritize them for funding, research and potentially future regulation.

"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," Zeldin said at a press conference at EPA Headquarters.

The Trump Administration's Contaminant Candidate List

The EPA's Contaminant Candidate List identifies contaminants in drinking water that are not yet regulated under the Safe Drinking Water Act but may require regulation in the future. The agency publishes the list every five years.

The draft Sixth Contaminant Candidate List (CCL 6) includes four contaminant groups — microplastics, pharmaceuticals, PFAS (per- and polyfluoroalkyl substances, or "forever chemicals"), and disinfection byproducts — as well as 75 chemicals and nine microbes that may be found in drinking water.

For the first time in the program's history, EPA is designating both microplastics and pharmaceuticals as priority contaminant groups. The proposal is open for public comments through June 1.

The EPA is due to publish an updated list of contaminants that require monitoring — known as the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) — by the end of 2026.

Michigan's Push for Monitoring

In December, Whitmer joined six other Democratic governors to petition the EPA for a monitoring requirement, arguing it would "lead to meaningful methods of reducing the risk to the public's health."

The petition came after environmental groups in Michigan and beyond called on the governor to take action. They argued that microplastics and pharmaceuticals were already contaminating Michigan's water supplies, particularly in the Great Lakes, which serve as a drinking water source for 40 million people in the U.S. and Canada.

"We really should be taking action to protect people's health," said Sen. Jeff Irwin, D-Ann Arbor, who frequently sponsors legislation related to plastic pollution. "But we expect so little from the Trump administration, even their acknowledgement that we're going to look at this and collect data is probably a good thing."

What Are Microplastics?

Microplastics are tiny plastic fragments of 5 millimeters or less (about the width of a pencil eraser). They have turned up in human breast milk, blood and brain tissue. They come from litter that breaks down in the environment, fleece clothing that sheds fibers with every wash, car tires that grind away on road surfaces and many other sources.

In the Great Lakes, about 22 million pounds of plastic waste enters the water each year. While research on humans is limited, animal studies have linked microplastics exposure to learning and memory issues, reproductive problems and a host of other concerns.

Pharmaceutical Contamination

Pharmaceuticals range from anti-anxiety drugs to antibiotics and pain relievers that enter water supplies through human waste, improper drug disposal and intensive livestock operations that routinely dose animals with antibiotics and other drugs.

Pharmaceuticals have shown up at sampling sites across the Great Lakes and in the drinking water of tens of millions of U.S. residents. In the environment, they can harm aquatic life and give rise to antibiotic-resistant bacteria.

"We're consuming this stuff, and we really don't know what the risk is," said Art Hirsch, co-founder of the Michigan Microplastics Coalition.

State Action on Microplastics

While the EPA's announcement was seen as progress by some, environmental groups in Michigan are calling for more aggressive action.

Samantha Pickering, who leads the public and environmental public health program at the Michigan Environmental Council, said the EPA's acknowledgment of the problem is good but there's more that should be done now.

"I appreciate that the EPA is acknowledging that they're going to start watching it, but it needs to be shifted into a precautionary approach," Pickering said. "I don't see why they wouldn't be able to start taking action."

Pickering noted that Michigan is ahead of the federal EPA in tackling the problem. Michigan will be conducting a pilot to test five different drinking water systems for the contaminants, and for the next three years, will test about 200 of its inland lakes and streams for microplastics.

California, she said, has passed a law requiring the adoption of a system for testing drinking water supplies for microplastics.

Active State Legislation

Active bills in the Michigan Legislature to phase out microbeads, require drinking water providers to monitor for microplastics and create a statewide microplastics plan are awaiting votes in the state Senate.

Past efforts to let local governments ban plastic bags, expand recycling programs and ban cosmetics and over-the-counter drugs containing plastic microbeads have all stalled.

"We're never going to get rid of plastics," Hirsch said. "They're too fundamental. The problem is, we make too much."

The Regulatory Process

The proposal to designate microplastics and pharmaceuticals as priority contaminants is expected to be finalized by the EPA by November 17, 2026. The CCL is the first step in the SDWA regulatory process.

In the past, the EPA has determined that no regulatory action is appropriate or necessary for most of the contaminants it has considered. The NRDC and other environmental advocates are fighting to keep the Biden-era rule in place limiting PFAS in drinking water.

Industry Response

The American Chemistry Council, an industry group, said it supports monitoring of microplastics in drinking water and research to better understand potential impacts, as long as the monitoring is standardized and consistent nationwide.

At the federal level, Congress passed 2015 legislation phasing out personal care products containing plastic microbeads and directed EPA in 2020 to develop a national strategy on plastic pollution. Several other efforts to rein in plastic use have stalled, while President Trump last year reversed a Biden-era effort to phase out federal use of single-use plastics.

The proposal to designate microplastics and pharmaceuticals as priority contaminants is open for public comments through June 1.