Drinking water systems serving at least six million Americans have shown levels of C8 and other similar chemicals higher than a health advisory issued earlier this year by the U.S. Environmental Protection Agency, according to a new study published Tuesday by researchers from Harvard University and several other institutions and groups.
The study, though, cautions that another 44.5 million Americans rely on private wells that generally have not been sampled for these chemicals and another 52 million residents are served by small drinking water systems that are rarely sampled. And, the study further warns, studies continue to strongly suggest that exposure to these chemicals can make people sick, even at or below the concentration recommended as acceptable under the EPA health advisory.
"The EPA advisory limit ... is much too high to protect us against toxic effects on the immune system," said study co-author Dr. Philippe Grandjean of the Harvard School of Public Health. "And the available water data only reveals the tip of the iceberg of contaminated drinking water."
The study, published in the peer-review journal Environmental Science and Technology Letters, comes amid growing new attention for the potential threats from C8 and similar chemicals in the months following their discovery in water systems in New York and Vermont - a development that has driven political and media focus on the issue as residents near a DuPont Co. plant in Wood County, West Virginia, have waited for years for EPA to publish its new guidance.
The mid-Ohio Valley region around Parkersburg has for years been at the center of a simmering controversy over C8 pollution that has in recent months exploded into a larger national issue, with more intense media coverage, growing concerns in a variety of communities, and verdicts against DuPont in the first of thousands of pending personal injury cases to go to trial in a federal court in Ohio.
C8, which is also known as perfluorooctanoate acid, or PFOA, was made and used at DuPont's Washington Works plant south of Parkersburg as a processing agent to make Teflon and other nonstick products, oil-resistant paper packaging and stain-resistant textiles.
DuPont and other companies have agreed on a voluntary phase-out of the chemical, but researchers noted in this week's study that declines in production in the U.S. and Europe have been offset by increases in developing regions such as Asia. Scientists have also been increasingly concerned about chemical contamination of consumer products, and the new study provides important details about the potential threats from waste disposal practices and varying uses of the substances.
The study used computer mapping techniques to try to pinpoint the locations of contaminated drinking water supplies relative to potential sources of C8 contamination. Researchers said that they were hampered by the fact that regulators keep exact locations of drinking water intakes confidential, citing concerns about potential terrorist attacks. Instead of looking specifically at intake locations, the study focused on broader areas around those intakes, a move that may have missed impacts on groundwater, where contaminated plumes could be much smaller.
Researchers found that higher levels of chemicals were found in water supplies that were located closer to industrial sites, or to military bases or airports where firefighting foams containing some of the chemicals could have been used in emergeny drills. They also found higher levels in water supplies located near wastewater treatment facilities, which are generally not capable of removing the contamination as part of routine treatment.
Co-authors of the study included scientists from the University of California at Berkeley, the University of Rhode Island, the Colorado School of Mines, the Silent Spring Institute, the Green Science Policy Institute, the Environmental Working Group and EPA.
A second study that was also published Tuesday in the journal Environmental Health Perspectives added to previous evidence about immune system impacts of these chemicals, connecting early life exposure to reduced immune function.
Other recently published papers connected elevated exposure levels in women to shorter duration of breastfeeding, found higher levels of the chemicals in the blood of California women whose drinking water was contaminated, and found lower levels of growth and sex hormones in childen exposed to the chemicals.
Reach Ken Ward Jr. at kward@wvgazettemail.com, 304-348-1702 or follow @kenwardjr on Twitter.