[B]ennington residents tested for the water contaminant PFOA have the chemical in their blood at levels that average five times the national average, according to results the state released Tuesday.
The testing involved 477 people whose private drinking water has been contaminated with PFOA or who lived near or worked at the former Chemfab site in Bennington that is considered the source of the chemical.
The Vermont Department of Health urged affected residents to speak with their primary care physicians about specific concerns associated with elevated levels of PFOA, or perfluorooctanoic acid. The department said it has mailed results to residents who had the tests.
Vermont public health officials have repeatedly said that a high level of PFOA in a person’s blood does not predict future health issues.
A massive study in West Virginia linked the chemical to numerous maladies. The average blood concentrations of the chemical found there were several times higher than in Vermont.
“We knew people wanted to see these blood results … but there’s not a lot of actionable data from them,” said Vermont Health Commissioner Dr. Harry Chen.
Health Department staffers are still analyzing results and will try to correlate PFOA in water levels, in blood levels and in occupations where the chemical is in use, Chen said. Results of this analysis should become available within months, he said.
In blood from the Vermont adults and children tested, PFOA was found in concentrations ranging from 0.3 micrograms per liter to 1,125.6 micrograms per liter.
The geometric mean — a type of average — of the samples was 10 micrograms per liter, the state said, around five times the national average of 2.1 micrograms per liter. Of Americans who have been tested for PFOA, 95 percent were found to carry fewer than 5.7 micrograms per liter in their blood, according to materials the Department of Health released with the Vermont test results.
The department used the geometric mean because that is the metric by which PFOA concentrations are usually described, Chen said.
In Hoosick Falls, New York, where a similar PFOA release is under investigation, Chen said, blood tests returned a geometric mean of 23.5 micrograms per liter. Blood tests from West Virginia residents living near a DuPont factory on the Ohio River returned a geometric mean of 32 micrograms per liter, Chen said. Workers in factories that used PFOA in industrial processes have returned results with a geometric mean of 1,100, he said.
The geometric mean is a helpful way to look at PFOA blood tests because it reduces the effect of results far outside the norm, Chen said.
The Health Department collected the blood samples between April and June. The U.S. Centers for Disease Control and Prevention did the testing.
PFOA was used to manufacture Teflon products until the industry voluntarily phased it out by 2015.
The chemical breaks down in the human body, but it takes two to four years for the body to reduce PFOA concentrations by half, according to the U.S. Agency for Toxic Substances and Disease Registry.
The Environmental Protection Agency earlier this year set an advisory limit of 70 parts per trillion in drinking water for PFOA. The number is a guideline for operators of water systems, not a regulation. The EPA said it provides “a margin of protection from a lifetime of exposure.”
Vermont also put in place a rule this year setting a limit of 20 parts per trillion. State toxicologist Dr. Sarah Vose has said Vermont’s Health Department arrived at the lower number out of concern for infants and their increased sensitivity to PFOA.
More than 150 North Bennington and Bennington wells have been found to contain perfluorooctanoic acid at levels over 20 parts per trillion.
The EPA several years ago set a preliminary advisory limit of 400 parts per trillion.
Vose has said Vermont relied in part on a nearly 300-page study by the EPA on PFOA’s health effects, a draft of which the agency released in 2014.
The EPA said research indicates that exposure to PFOA over certain levels may result in low birth weight or birth defects; testicular and kidney cancer; liver damage; effects on the immune system and thyroid; and other harm.
A lawsuit against the chemicals corporation DuPont in the 1990s revealed the company knew decades earlier of human health risks associated with PFOA. The settlement funded an unprecedented study of PFOA’s long-term effects on workers and residents near one of the company’s West Virginia factories.
The study found a close relationship between PFOA and several types of cancers, as well as attention deficit disorder, hypertension and high cholesterol.
The Vermont Department of Environmental Conservation has been testing wells and water supplies near industrial facilities for PFOA contamination since the beginning of the year. The chemical has been found in nearly 200 residential wells in North Bennington, in a municipal water supply in Pownal, in an underground storage tank at the Pittsford Fire Academy and in a groundwater collection trench at the Air National Guard Base in South Burlington. Groundwater sources in Essex Junction and Colchester near former factories also recently tested positive for the chemical.
The state has held several blood testing clinics for residents affected by PFOA-contaminated water but has none scheduled now. The Department of Health said it may hold a final blood draw clinic in the fall.
The tests are provided for free to anyone whose well the DEC has tested for PFOA, anyone who lived in a house within the past eight years that the DEC has tested for PFOA, and anyone who has worked at or lived near the former Chemfab plant in North Bennington.
Residents can find out about future testing and register for an appointment here.
