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Persistent Pollutants

Perfluorinated chemicals taint drinking water

Linked to health problems, PFOA and PFOS leave a legacy that EPA is just starting to address

by Jessica Morrison
May 11, 2016 | A version of this story appeared in Volume 94, Issue 20


Credit: Steve Johnson/Flickr
Credit: Steve Johnson/Flickr

Remnants of past industrial chemical innovation linger in rivers and aquifers that supply drinking water to millions of people in the U.S., and more worldwide, potentially putting their health at risk. Dissolved in the water are perfluorinated compounds that gave rise to iconic household brands such as 3M’s Scotchgard and DuPont’s Teflon.

In places such as Parkersburg, W.Va., where a DuPont plant used perfluorooctanoic acid (PFOA) for decades, residents are turning to bottles of water rather than turning on unfiltered taps because of contamination of the local water supply. DuPont and other firms that made or used PFOA are likely to be on the hook financially for personal injury claims or cleanup for years to come.

PFOA, sometimes called C8, has been linked to disease, including high cholesterol, thyroid disease, and some cancers.

Although the U.S. Environmental Protection Agency began working with the fluorochemicals industry more than a decade ago to phase out production, some say the agency has been slow to provide advice to health officials for PFOA and a related compound, perfluorooctane sulfonate (PFOS), which was once a key material in 3M’s Scotchguard products. Both chemicals are chains of fluorinated carbon atoms with either a terminal sulfonic acid (PFOS) or carboxylic acid group (PFOA). Neither is made or used in the U.S. for manufacturing anymore, but the chemicals persist in the environment because of the strength of the carbon-fluorine bond.

In a matter of days or weeks, EPA is expected to suggest a maximum level of PFOA and PFOS in drinking water that would likely be safe if a person drank the water over a lifetime. The move would not force regulators to limit these synthetic chemicals in drinking water, but it would, for the first time, provide technical guidance to state and local government officials charged with protecting the public’s health. EPA’s guidance would account for continuous rather than short-term exposures to the contaminants.

PFOA and PFOS contamination in drinking water is thought to stem from two main sources: factories that formerly manufactured or used the chemicals, and locations, including military bases, where they were used in firefighting foams. In addition, PFOA and PFOS may also end up in the environment as fluorochemical-containing consumer products such as stain-resistant fabric or grease-proof food wrappers break down. Both PFOA and PFOS are found at very low levels in the blood of the general population across the U.S., according to EPA.

For those who have been drinking contaminated water near primary sources for decades, the upcoming federal guidance comes too late, some argue.

Environmental attorney Robert A. Bilott tells C&EN that he and others for years have asked EPA to do more about long-term exposure to perfluorinated chemicals.

“That is something that could have been and should have been done 15 or 16 years ago,” says Bilott, the environmental attorney known for taking on corporate giant DuPont at the behest of a West Virginia farmer whose land and water was tainted with PFOA from the Parkersburg plant. Because EPA officials “waited so long and the chemical is now being found in so many places,” he says, “I think they’re going to have a hard time explaining why they didn’t act sooner.”

For decades, studies have suggested health risks associated with PFOA and PFOS, which have been found in drinking water supplies that serve millions of people in the U.S. For instance, in 2005, a panel of external science advisers to EPA said the agency should classify PFOA as “likely to be carcinogenic” in humans. Most of the panel said enough evidence existed from human biomonitoring studies to evaluate the environmental risk of PFOA for the general population. EPA’s upcoming guidance is expected to reflect the findings of that decadelong evaluation. Meanwhile, researchers have linked PFOA to other health problems.

“People started looking over the last 10 years for adverse effects” from exposure to PFOA and related compounds, says Philippe Grandjean, an environmental health scientist at Harvard T.H. Chan School of Public Health who studied immunotoxicity in children and found a link between exposure to perfluorinated compounds and weakened response to vaccines. “We were thinking in the beginning that a carbon chain wrapped in fluoride ions seems like it won’t do anything. It’s certainly very stable, but the question is, will it interact with biological molecules and cause any adverse effects?”

The answer to that question has been sought in courtrooms as well as laboratories.

A team of independent researchers, known as the C8 Science Panel, was formed in 2005 as part of a settlement of a class-action lawsuit against DuPont. That suit alleged that residents living near DuPont’s Washington Works plant outside of Parkersburg, W.Va., were harmed by exposure to PFOA released by the facility that reached groundwater and contaminated wells that supply public drinking water.

The C8 Science Panel between 2005 and 2013 carried out a series of exposure and health studies and released a string of reports about the links, or lack thereof, between PFOA exposure and over 30 diseases. The team found probable links between exposure to PFOA and six of those diseases: high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced hypertension.

Funding for the panel was part of a $107.6 million settlement DuPont paid in the class-action lawsuit. DuPont later reached a separate $16.5 million deal with EPA to clear allegations that the company withheld information from the agency about PFOA detected in its workers’ blood.

Now, DuPont faces some 3,500 personal injury cases related to PFOA exposure from Washington Works. Financial liability, however, will fall to DuPont spin-off Chemours, which now manages the larger company’s fluoropolymers business.

DuPont lost the first of these cases last year, with a jury awarding $1.6 million to an Ohio woman who alleged PFOA exposure from DuPont’s facility caused her kidney cancer. Beginning in spring 2017, the judge overseeing the cases expects to schedule 40 trials per year.

The original maker of PFOA, 3M, is also facing class-action lawsuits. Litigation is ongoing near places where 3M manufactured the chemical in Cottage Grove, Minn., and Decatur, Ala.

As lawsuits continue, communities and state regulators facing contaminated water supplies are questioning why EPA hasn’t established a lifetime health advisory for perfluorinated chemicals in drinking water.

In 2009, EPA set a preliminary health advisory for drinking water of 400 parts per trillion for PFOA and 200 ppt for PFOS. Many expect the agency’s upcoming lifetime health advisory for PFOA to be tighter, at or near 100 ppt. That lower number would reflect a recommendation EPA made in January to Hoosick Falls, N.Y., where PFOA contaminates drinking water wells: The agency suggested residents use bottled water for drinking and cooking when levels of the chemical in their household water supplies is measured at 100 ppt or higher.

In Hoosick Falls, New York officials traced PFOA contamination in public and private wells to manufacturing facilities owned by Saint-Gobain Performance Plastics and Honeywell International. The state wants the companies to cover the costs of providing safe drinking water to area residents and remediating the pollution. Regulators there have installed a municipal activated-carbon filtration system to remove PFOA as well as more than 200 individual carbon filtration systems for homes with private wells. They’ve received requests for hundreds more, the New York State Department of Environmental Conservation says.

Other states facing drinking water tainted with PFOA and related compounds have set their own health advisories that are lower than the current 400-ppt preliminary guidance from EPA. Their stricter advisories reflect, in part, a desire to mitigate potential health effects associated with chronic exposure to contaminated drinking water rather than short-term exposure.

For example, in Vermont, where a fabric manufacturing plant in North Bennington is the suspected source of PFOA contaminating municipal and private wells, the state health department set a health advisory level of 20 ppt. Vermont considered EPA’s preliminary guidance for PFOA then chose to establish its own health advisory level that would account for long-term exposure.

“We did not think it was appropriate to use a short-term health advisory,” says Sarah Vose, state toxicologist for the Vermont Department of Health.

New Jersey also took a stronger stance on identifying and mitigating contamination from PFOA and related chemicals after finding contamination in surface and groundwater near manufacturing sites throughout the state. New Jersey set its health advisory level for PFOA at 40 ppt in 2007.

EPA issued its preliminary health advisory based on short-term potential toxicity, while New Jersey, like Vermont, made mitigating long-term chronic health effects a priority, says Lawrence Hajna, a spokesperson for the New Jersey Department of Environmental Protection. “When you’re evaluating a standard for a short-term risk, you’re basically saying that you’re looking to protect somebody who’s just visiting a house. Our approach has been that somebody actually lives in that house.”

While states and EPA work to keep drinking water supplies safe, action is also coming from the U.S. Air Force and other branches of the military that have used aqueous firefighting foams containing PFOS and related fluorochemicals that can degrade to PFOA or PFOS. Late last year, the Department of Defense began looking for contamination at more than 600 training sites in the U.S., two-thirds of which are Air Force bases. The Air Force began to curtail its use of foams containing perfluorinated compounds for firefighting training exercises in the 1980s. However, it still uses the foams in actual emergency responses.

Chemical makers, too, have taken steps to curb the use of PFOA and PFOS. 3M, which began producing PFOA, PFOS, and related fluorinated chemicals in the 1940s, announced unexpectedly in 2000 that it would end production of PFOS. Nearly six years later, in an EPA-led effort, 3M, DuPont, and six other chemical manufacturers agreed to voluntarily eliminate PFOA and related fluorinated compounds from their products and facility emissions worldwide by 2015.

FluoroCouncil, part of the industry trade group American Chemistry Council, says the stewardship program is “a solid example of how industry and EPA can work together to ensure that concerns are addressed without compromising the many important benefits that these chemistries provide.”

Earlier this year, EPA said the companies had met their commitments, but it has not released an anticipated final report on the companies’ efforts. The companies have switched to shorter-chain perfluoroalkyl alternatives that—though their health risks are not yet fully understood—are still persistent, but less bioaccumulative.

Most applaud these companies’ voluntary move to eliminate some fluorinated chemicals from their inventories and, by consequence, the environment. Still, some experts say that PFOA and PFOS may be entering the environment anyway because new fluorinated chemicals and their intermediates may degrade to form PFOA and PFOS.

The complex chemistry of perfluorochemicals poses a challenge to researchers trying to tease out the sources of these substances and how they behave in the environment, says Christopher P. Higgins, an environmental chemist and professor at Colorado School of Mines.

Higgins, who studies the environmental fate of poly- and perfluoroalkyl substances (PFASs) used in firefighting foams and consumer products, says many compounds may break down into PFOA and PFOS. “We are still figuring out what some of those are.”

Because PFOA was a minor component in the production of many of the aqueous firefighting foams and consumer products that Higgins studies, he says elevated PFOA in groundwater impacted by these materials is evidence of likely transformation of other fluorochemicals to PFOA over time.

PFOA doesn’t break down in the environment. EPA says the chemical “does not hydrolyze, photolyze, or biodegrade under environmental conditions.” Neither does PFOS. Both substances accumulate in living things, with elimination half-lives of three to five years, before returning to the environment.

Research has shown that the length of a perfluorinated chemical’s carbon chain affects its ability to bioaccumulate. That finding has led manufacturers to produce shorter perfluorinated molecules with chains of six fluorinated carbons or fewer as replacements for PFOA and PFOS.


But shortening the chain length doesn’t affect the stability of perfluorocarbons in the environment, says Jessica C. D’eon, a chemistry professor at the University of Toronto.

“We haven’t really changed the persistence, but we have changed the accumulation ability,” D’eon says. “A chemical that won’t accumulate in your body won’t get to a concentration where it’s going to be a problem.”

Because perfluorinated chemicals aren’t known to degrade under conditions found in the environment, PFOA, PFOS, and their new shorter-chain successors will continue to linger indefinitely.

“Some people have said these compounds redefine persistence,” D’eon adds.


EPA released lifetime health advisories for PFOA and PFOS on May 19, 2016. Read the full story here.


This story was updated on May 16, 2016. The story incorrectly stated that the number of fluorinated carbon atoms in perfluorooctanoic acid (PFOA) is eight. PFOA has seven fluorinated carbon atoms.


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