Fisk says PFOA is concerning, in part because of its chemical makeup. It has a long tubular body made of eight carbon segments, and fifteen legs made of fluorine. At the end of the chemical compound, oxygen and hydrogen bond to the carbon to form carboxylic acid. The result, Fisk says, is a very slippery compound.
"That's what makes these things so persistent – because the fluoride chain helps repel oil and water."
Once PFOA enters the environment it doesn't easily break down, while in living organisms, it tends to build up, according to Environmental Working Group. Research Analyst Kristan Markey says:
"It concentrates much more in the blood. Once there, if there are no other sources of PFOA, it tends to stay, on average, 20 years. It takes about 4 years to reduce 50% in your blood."
PFOA repels oil, so in the body, it migrates towards non fatty organs, mainly the liver and kidneys. That concerns researchers like Markey because there are many studies showing PFOA "will probably cause cancer in the long term."
The US Environmental Protection Agency lists PFOA as a likely carcinogen. Markey says the problem is that the classification "doesn't tell us how much" PFOA exposure is necessary to risk cancer.
The EPA's director for the office of pollution, prevention and toxics, Charlie Auer, says the classification essentially means more studies are needed.
"The important point to understand is this judgment is at an early step in our risk assessment process. So we're really not at a point to offer risk conclusions on PFOA. It's a very complex area. It's one where the research is still coming in."
There are other studies linking PFOA to other negative health effects. A John Hopkins Bloomberg School of Public Heath study shows an association between fetal PFOA exposure and low birth weight in humans. Numerous other animal studies have raised concern about what impact PFOA might have on dementia, liver enlargement and birth defects.
Several studies suggest carbon filtering could dramatically lower PFOA output into the river.
