The George Rogers Clark Memorial bridge crosses the Ohio River to Louisville, Kentucky.
Visions of America/Joseph Sohm/Universal Images Group via Getty Images
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Visions of America/Joseph Sohm/Universal Images Group via Getty Images
The Ohio River sends billions of gallons of water flowing past Louisville, Kentucky’s pumping station every day, where the city’s utility sucks it up to turn it into tap water.
To ensure it tastes good and is safe to drink, a small team of scientists and technicians is constantly testing the water for pH, odors, heavy metals and microbes.
But unlike many smaller municipal utilities across the U.S., the Louisville Water Company regularly checks for PFAS (per- and polyfluoroalkyl substances).
That’s a class of chemicals, used by manufacturers for decades to make things like nonstick pans, cosmetics, raincoats, food wrappers and firefighting foam.
Research studies have linked PFAS to health risks like cancer, reduced immune system functioning, high cholesterol, and developmental delays in children.
They’re also known as “forever chemicals” because they’re practically indestructible. Their strong chemical structures make them degrade incredibly slowly in the environment.
Today, they litter soil and water sources across the world and can be found in the blood of almost everyone in the U.S.
One type of PFAS that the Louisville water technicians are tracking is HFPO-DA, though it’s perhaps better known by a trade name, GenX.
Almost a year ago, workers noticed an unexpected spike in the level of GenX detected in a sample of the raw, untreated water drawn from the Ohio River for filtering and processing.
In water, PFAS concentration is measured in parts per trillion. The GenX levels they found last December were 15 times higher than the previous month: 52 parts per trillion versus 3.4 parts per trillion.
“A part per trillion is like one second in 32,800 years. Put your head around that, right?” said Peter Goodmann, the city utility’s director of water quality and research.
Another way to think of it: One part per trillion would be a single drop within 20 Olympic swimming pools.
So the increased levels were still pretty low, he said.
