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DES: Rise in PFOA levels not alarming

By Staff | May 11, 2016

MERRIMACK – Another round of water testing conducted at the Merrimack Village Water District shows that the concentration of a potentially carcinogenic acid has grown in most cases.

The concentration of perfluorooctanoic acid – or PFOA – in the wells used by 95 percent of the town of Merrimack generally falls well below the state’s provisional 100 parts-per-trillion safe exposure limit. However, one of the wells, which was sampled on March 31 and April 7, shows a concentration increase from 90 parts per trillion to 94 parts per trillion in just eight days.

Jim Martin, DES spokesperson, said the increased level of PFOA concentration isn’t necessarily a cause for concern.

"It is important to note that sampling for compounds at part per trillion levels in drinking water will exhibit variability from week to week," he said in a statement. "Factors such as recent precipitation trends, how much water is being pumped from the well, the on and off cycling of the well and small variations associated with each lab analysis can cause concentrations to increase or decrease from week to week and seasonally."

"Long term trends in water quality are significant if concentrations consistently trend in an upward or downward direction after an extended period of time," he said. "Consistent and long term water quality trends will indicate if concentrations of PFOA are decreasing or increasing in water derived from the wells. The weekly sampling occurring for MVD’s wells will provide this information. Meaningful conclusions cannot be made based on the results of only a few weeks of sampling."

While New Hampshire has issued no lifetime advisory limit for the chemical, other states have set their own limits. DES is currently using the limit set by Maine at 100 parts per trillion. Vermont sets its lifetime limit at 20 parts per trillion. The U.S. Environmental Protection Agency recommends avoiding short-term exposure to more than 400 parts per trillion, but that agency has not yet published a lifetime advisory limit for PFOA exposure.

The testing of water supplies in Merrimack follows the discovery and voluntary reporting of elevated PFOA levels in the tap water at the Saint-Gobain Performance Plastics facility on Daniel Webster Highway. That company, which has never manufactured PFOA but used it in industrial applications, has not been declared responsible for the contamination of water supplies, but nevertheless has agreed to fund the distribution of bottled water to affected residents near their plant.

Exposure to PFOA has been linked to several serious diseases. According to a court-ordered study known as the "C8 Science Panel," which was conducted following a class-action lawsuit settlement over PFOA contamination in the Ohio Valley, there is a probable link between PFOA exposure and diagnosed high cholesterol, ulcerative colitis, thyroid disease, testicular and kidney cancer, and pregnancy-induced hypertension.

Although the exact health effects of exposure are still up for debate, some experts have suggested avoiding exposure to any amount of the acid. According to professor Philippe Grandjean of the Harvard T.H. Chan School of Public Health, exposure to even 1 part per trillion of PFOA is dangerous for children. He said the EPA has grossly overestimated what is safe.

"The provisional water limits that EPA is using for perfluorooctanesulfonic acid and PFOA are perhaps 100-fold too high to protect children against adverse effects on their immune system in regard to antibody responses to childhood immunizations," he said in an email.

The results of further testing are pending. For more information please visit des.nh.gov.

Matthew Medsger can be reached at 594-6531, mmedsger@nashuatelegraph.com or @Telegraph_MattM.

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