A new study has found that people who lived in the Ohio River Valley between 1991 and 2013 have higher levels of a chemical called PFOA in their bloodstream than the national average.
PFOA, also called C-8, is a toxic chemical that was used to make products including non-stick cookware for decades. Its impact on health is the subject of ongoing study; even small amounts are thought to cause larger body mass index in adults, negative responses to vaccines and smaller birth weight in babies.
PFOA was manufactured, among other places, at the DuPont plant in Parkersburg, West Virginia. That plant no longer uses PFOA, and as a result of a class action lawsuit and settlement, scientists found links between several types of cancers and PFOA exposure.
But the community surrounding the DuPont plant wasn’t the only one exposed to the chemical. It was discharged into the Ohio River for years, and numerous communities — including Louisville — get drinking water from the river.
Importantly, the study is looking backward, not forward.
“There really is no concern for drinking water today,” said University of Cincinnati professor and study co-author Susan Pinney.
Now that PFOA is known to be a problem, many water treatment plants use granular activated carbon, which filters PFOAs. The water is also routinely tested for the chemical.
Monthly Testing In Louisville
In Louisville, Louisville Water Company spokeswoman Kelley Dearing Smith said the company tests monthly for PFOAs and PFOS, a related chemical.
There’s no federal standard for the chemicals, but there’s a health advisory level of 70 parts per trillion. Based on the past year and a half of data, the average amount of the chemicals found in the water company’s Crescent Hill Plant is 7 parts per trillion; for the B.E. Payne plant, it’s 9.5 parts per trillion.
Neither of the company’s plants use granular activated carbon; Dearing Smith said so far, it’s not been necessary.
“Our scientists don’t see this as a public health concern right now, based on the levels we’re seeing,” Dearing Smith said. “This is one of those things where even advanced treatment technology doesn’t entirely wipe out the threat. The best treatment options right now for PFOA would really be to change where you’re getting your water from, if you had really high levels.”
While it’s not a current concern, people who lived in Ohio Valley for the past few decades have likely been exposed to the chemical.
Using blood samples from people who lived along the Ohio River in the 1990s and early 2000s — mostly in Cincinnati and Northern Kentucky, but also in Louisville; Portsmouth, Ohio; and Huntington, West Virginia — researchers found levels of PFOA higher than the national average.
“And between that and being able to associate it with the body of water they got their drinking water from, we were able to say pretty conclusively that drinking water from the Ohio River and the Ohio River aquifer is a major source of exposure to PFOA,” said study lead author and University of Cincinnati graduate student Robert Herrick.
Implications For Future Health
The study found the most important factor that dictated how much PFOA was in a person’s bloodstream wasn’t how close they lived to the places that manufactured the chemical.
“Levels in the river itself decrease as you go downriver, but levels in people don’t necessarily decrease as you go downriver,” Herrick said. “The type of water treatment has a very big effect.”
Granular activated carbon is the most effective way to remove PFOA from drinking water. Cincinnati’s water system installed a system in 1992, while across the river, Northern Kentucky’s waterworks didn’t install one until 2012.
And while the amount of PFOA in the river would be similar at both sites, Herrick said people who got their drinking water from the Cincinnati water system had lower levels of the chemical in their blood than their Kentucky neighbors.
So, what does this all mean? Herrick and Pinney said understanding this historical data will help researchers in the future figure out what, if any, health effects can be linked to long-term PFOA exposure.
PFOA has pretty long half-life. Once it gets in your bloodstream, it takes two to four years for half of it to disappear. This means it sticks around for a very long time. Previous studies have linked high PFOA concentrations to a variety of conditions, like a larger body mass index in adults, a poor reaction to vaccines and a smaller birth weight for babies exposed in utero.
But Pinney said so far, there’s nothing conclusive. That’s where this study might help shed some light.
“We’re not saying people need to be very concerned about what they’re drinking today,” she said. “This is a historical study, but the importance of it is as we look toward the future, if we see some health effects we now know better that the exposure went back further and was actually greater in the early 1990s.”