Readers have asked The Dispatch for advice on the most effective way to remove PFAS — or "forever chemicals’’ that federal court-appointed research studies say can lead to cancer — from tap water. Here’s what experts had to say.

As consumers learn more about PFAS, or "forever chemicals,’’ some are asking: What’s the best way to treat tap water to reduce contamination?

After The Dispatch reported that both Columbus and Cincinnati have tap water containing the chemicals, which don’t break down and can accumulate over time, the newspaper received numerous calls and emails from readers.


So we asked experts for their advice and prepared this primer intended to help explain the problem and how consumers can deal with it:

What are PFAS chemicals?

PFAS chemicals, perfluoroalkyl and polyfluoroalkyl, are man-made and were developed for use in household goods including nonstick cookware, water-repellent fabrics and food wrappers.

But the chemicals, which remain unregulated at the federal level and at the state level in Ohio, were dumped into the environment for decades, court records show, contaminating drinking water.

Why should people be concerned?

The chemicals, which are now everywhere in the environment, can linger for decades in blood and organs.

Court-appointed researchers have found that someone who drinks water with 50 parts per trillion of PFOA (one of the most studied chemicals in the PFAS family) for a year or more is more likely to get testicular or kidney cancer, thyroid disease, ulcerative colitis, high cholesterol and preeclampsia, a condition that can cause organ damage in pregnant women.

At least 16.4 parts per trillion of nine different forever chemicals were found recently in Columbus’ drinking water, according to the Environmental Working Group, or EWG, a nonprofit, nonpartisan environmental group that conducted the study.

Columbus Division of Water officials acknowledged it would take tens, maybe hundreds, of millions of dollars to reduce the chemicals to very low levels.

As government agencies grapple with how to best regulate forever chemicals and determine what level, if any, is safe, consumers are left to take action on their own.

"That's a personal decision people have to make depending on what they can afford and what they're comfortable with," said Heather Stapleton, who specializes in ecotoxicology and environmental health at Duke University’s Nicholas School of the Environment.

"Even within your price range, there could be a lot of variability in the manufacturers, and it’s often hard to evaluate how well they work.

"So it does present quite a bit of a challenge in terms of trying to make an informed decision."

What’s the most effective way to remove forever chemicals from tap water?

Experts agree the best method to remove PFAS chemicals is to use a reverse osmosis system installed under the kitchen sink.

"Reverse osmosis is going to be the most effective technology to remove a wide variety of different PFAS," said Tasha Stoiber, an EWG senior scientist.

Stapleton, who was part of a team of researchers from Duke and North Carolina State universities, published a study last week that evaluated a variety of water filters and their effectiveness in removing PFAS.

Water was tested in 75 homes, of which 12 used reverse osmosis systems. Those systems removed 96% or more of PFAS chemicals.

"It didn't matter what type or manufacturer. They all performed very well. Reverse osmosis very clearly seems to be a good choice for removing these compounds," Stapleton said.

"On the flip side, we have to keep in mind that those types of systems can be fairly expensive for the average family," she said. "I put one in my own home, for example, an under-the-sink unit just used for drinking and cooking. It costs about $350 to purchase, but then to replace the filters every year is about $100.’’

The other downside is that a reverse osmosis system can waste water because of how it works: Tap water runs through a semipermeable membrane that blocks any particles bigger than water molecules. Some reverse osmosis systems have a sediment filter as well as activated carbon filters that can remove additional contaminants, according to the EWG.

(Another option is the ion exchange system, which softens water and in some cases can remove PFAS. This is often a more expensive option.)

If you can’t afford a reverse osmosis system or don’t want to go that route, what’s the next option?

Some activated carbon filters are capable of removing PFAS chemicals and come in a variety of forms, including pitcher, refrigerator and faucet filters.

The Duke study found that refrigerator and pitcher filters removed about 50% of PFAS chemicals, though their efficiency varied considerably depending on usage.

The EWG recommends looking for filters certified by an independent, third-party certification company.

"The drawback with activated carbon (filters) is they will lose effectiveness over time if you don't promptly replace the filter cartridges,’’ and they might not be as effective for certain types of PFAS chemicals, Stoiber said.

What about bottled water?

Stapleton said many bottled water companies use reverse osmosis to treat water, which would make it safe to drink, but she suggested checking the label for the source of the water.

Beware of a lack of transparency, though: Local water utilities are required by law to test for contaminants each year and report results to the public, but bottled water companies don’t have to disclose results, Stoiber said.

In addition, check the label on bottled water to determine its source. Some bottled water comes from municipal water-treatment plants like Columbus.

Should you worry about filtering water used for showering or brushing your teeth?

Most people acquire the chemicals by drinking water.

"Research always changes, but based on what we know ... we literally have to drink it, to consume it,’’ Stapleton said. "For actual exposure and accumulation, body showering seems to be negligible with dermal contact. Even cooking seems to be relatively negligible, although I certainly always, for personal reasons, advise that people try to cook with filtered water if that’s an option for them."

What action is Ohio taking?

In September, Gov. Mike DeWine ordered that 90% of the state’s public water systems be tested for PFAS chemicals. That testing is expected to take all year.

While other states have set limits on the chemicals, Ohio has not. The U.S. Environmental Protection Agency has an "advisory limit’’ set at 70 parts per trillion.

Researchers with the EWG believe anything above 1 part per trillion can cause harmful health effects.

A bill was recently introduced in the Ohio legislature that would require the Ohio EPA to set a maximum contaminant level for the chemicals.

Rep. Allison Russo, D-Upper Arlington, who is co-sponsoring the bill, recently learned about PFAS levels in Columbus’ drinking water.

"It's surprising. I live here. I drink the water here. I give the water to my kids. Yet to know we are ... above where the evidence suggests is safe is concerning," she said. "I don't yet know what we can do from a home-system perspective. We shouldn't assume that people will be able to take these steps on their own."

Given the widespread presence of the chemicals, she said, the state should set limits and not wait for testing or for the U.S. EPA to take action.