'Forever chemicals': What is the level of PFAS in Louisville’s drinking water?

Connor Giffin, Louisville Courier Journal
·4 min read
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Earlier this year, the U.S. Environmental Protection Agency issued the first-ever national drinking water standards for per- and polyfluoroalkyl substances, or PFAS.

PFAS are a class of synthetic chemicals, sometimes called “forever chemicals” for their extreme persistence in the environment.

Scientists are increasingly learning how PFAS — which have been found in nearly every corner of the planet — pose a threat to public health. Research has linked the chemicals to some cancers, as well as altered metabolisms, weakened immune systems and other emerging concerns.

Louisville Water Co. has been evaluating its source water and finished water for PFAS for more than a decade, according to the utility. Here’s what recent sampling shows:

How much PFAS is in Louisville drinking water?

Monitoring data from Louisville Water Co. — responsible for treating drinking water before it reaches Louisville's taps and ensuring it meets federal standards — shows the utility is in compliance with the EPA’s new limits for PFAS.

There are still trace amounts of PFAS in the water at the utility’s Crescent Hill Water Treatment Plant, according to monitoring last year, and not every sample was below the EPA limit.

In one sample, the utility detected PFOA at 7.5 parts per trillion, above the EPA’s limit of 4.

One part per trillion is comparable to one drop of ink in the water of 20 Olympic-sized swimming pools. The limits set by the EPA for PFAS are about as low as scientists can reliably measure the chemicals.

Louisville Water Co. is in compliance with the EPA regulations because the limits are based on the running annual average of sampling, not individual samples.

An individual sample above the federal standard does not amount to a violation for the utility, “and one sample doesn't dictate public health,” water company spokesperson Kelley Dearing Smith previously told USA TODAY.

“The top line for the new PFAS regulation is that we meet the EPA's new standard,” Dearing Smith said in an email. She added the utility is working to implement additional water treatment to reduce PFAS levels further.

How does PFAS exposure occur?

PFAS have been found in the packaging of the food we eat and the fabrics of the clothing we wear.

As a result of its widespread use in consumer products, the chemicals have entered our air, soil and water. The Centers for Disease Control and Prevention estimates “nearly all people in the U.S. have had exposure to PFAS.”

The most common routes of exposure to PFAS, according to the EPA, include:

  • Working with PFAS, including firefighting or chemical manufacturing

  • Consuming contaminated drinking water

  • Consuming contaminated food, including fish

  • Breathing contaminated air or swallowing contaminated soil or dust

  • Using products made or packaged with PFAS

PFAS findings in Kentucky

Researchers in Kentucky have discovered PFAS nearly everywhere they’ve looked for it.In 2020, Kentucky’s Energy and Environment Cabinet sampled surface water at 40 different locations around the state in search of PFAS.

One or more of the chemicals were found at 36 of the 40 monitoring locations, and researchers determined “there is potential for PFAS occurrence within other Kentucky waterways that have not been evaluated.”

Following those findings, researchers searched for PFAS in fish tissue, taking 98 samples from fish in Kentucky water bodies.

They detected the chemicals in all 98 samples.

The Ohio River flows toward Louisville, just upstream of the city's water intake.
The Ohio River flows toward Louisville, just upstream of the city's water intake.

And in 2022, a study from the Ohio River Valley Water Sanitation Commission found PFAS up and down the Ohio River, which serves as a source of drinking water for millions of people.

In Louisville, where the water company has a team of scientists and more resources to address the threat of PFAS, levels of the chemicals presented at lower levels than in many other systems around the state and the country.

Small and rural water systems are already stretched thin, with underpaid staff often working to maintain crumbling and underfunded infrastructure.

For some of these systems, meeting stringent limits on PFAS will be a challenge. In addition to state and federal funding, Kentucky's rural water utilities rely on technical expertise and support from the state’s Division of Water.

Responding to PFAS contamination across the commonwealth, and ensuring public health standards are met, will be costly. Kentucky, like other states, is taking chemical industry giants to court for alleged contributions to PFAS contamination in the state’s waterways from upstream sources.In a lawsuit filed last year against DuPont de Nemours and two of its spinoff companies, Chemours and Corteva, Kentucky is seeking damages “to pay all past and future costs incurred by the Commonwealth in investigating, monitoring, and otherwise responding to PFAS contamination throughout Kentucky,” according to the complaint, “as well as damages for harm to the Commonwealth’s natural resources, caused by Defendants’ releases of PFAS.”

Connor Giffin is an environmental reporter for The Courier Journal. Reach him directly at cgiffin@gannett.com or on X @byconnorgiffin.

This article originally appeared on Louisville Courier Journal: PFAS in Louisville drinking water levels of forever chemicals