Ten Years Later, Chemical Safety and Justice for DuPont’s Teflon Victims Remain Elusive
Poisoned Legacy: PFC Contamination: No Place to Hide
PFCs in people
PFCs were first detected in human blood in 1976. Dr. Donald Taves of the University of Rochester's School of Medicine and Dentistry found that some of the fluoride in his own blood was organic and not related to the fluoride added to public drinking water supplies. Taves and his collaborators tentatively identified one of the chemicals as PFOA. (More than 20 years later, 3M said this was likely a misidentification of PFOS.) (Taves 1976, 3M 1999)
Over the next two decades, more than a dozen studies were published on blood levels of PFCs in the general population. In 2001 – four years after its futile worldwide search for blood samples not contaminated by PFOA and a year after it agreed to phase out PFOA and PFOS – 3M submitted a study to the EPA that found PFOA in the blood of 96 percent of 598 children tested in 23 states and the District of Columbia. In 2003-2004, the National Health and Nutrition Examination Survey, conducted by the Centers for Disease Control, found PFOA, PFOS and 10 other long-chain PFCs in 98 percent of a representative sample of the U.S. population. (NHANES 2015)
In 2005, EWG and Commonweal, a public health non-profit, obtained through the Red Cross samples of umbilical cord blood of 10 American newborns. Testing by two independent laboratories found that all ten had PFOA, PFOS or seven other long-chain PFCs in their blood – the first publicly reported tests to confirm that these chemicals could be passed from mothers to babies in the womb. (EWG 2005) In 2009, EWG and Rachel’s Network, another non-profit, commissioned tests on the cord blood of 10 newborns from African-American, Hispanic and Asian-American mothers and again found PFCs, including some of the next-generation replacements, in every one. (EWG 2009)
After decades of pollution from DuPont’s Washington Works plant in the mid-Ohio Valley, levels of C8/PFOA in people there were extraordinarily high. In 2003-2004, the National Health and Nutrition Examination Survey had found that the average level of PFOA in Americans was 4 parts per billion. (NHANES 2007) The C8 Science Panel found that the average in blood samples from the mid-Ohio Valley was 83 parts per billion. (Steenland 2009) The median level – the point at which half the samples were above and half below – was 28 parts per billion.
Blood levels in some groups sampled near the plant were even higher. The median level of C8 in people living closest to the plant, whose drinking water that came from the Little Hocking, Ohio, water district, was more than 224 parts per billion. The median level in workers currently employed at the plant was more than 147 parts per billion, and in former workers it was almost 74 parts per billion. C8 levels were higher in children, in people who ate local vegetables and in those who drank well water rather than public water. (Steenland 2009)
How do PFCs get into us?
People get contaminated with PFCs in just about every way imaginable – from drinking water, food and food packaging, indoor air, household and workplace air, carpet and furniture treatments, clothing, cosmetics, non-stick cookware and many other products. There is much uncertainty about how much exposure comes from each source. Early studies pointed to food and water as major sources and suggested that consumer goods were not significant. (Trudel 2008, Washburn 2005) A later study of blood serum levels found that indoor air in the workplace could be an important exposure pathway. (Fraser 2011)
Recently, EPA has suggested that the widespread presence of PFCs in human blood indicates that products treated to be stain-proof or waterproof could be a source. (EPA 2015B) In occupants of homes that are regularly treated with stain-resistant sprays, PFC levels can be much higher than in the general public. In children, who come into closer and more frequent contact with carpets and dust, levels are almost always higher than in adults. (Beesoon 2010, Mondal 2012, Toms 2009)
In 2009, EPA measured the chemical content of 116 products commonly treated with PFCs and estimated the typical amounts in a U.S. home. (Guo 2009) The results showed that more than 95 percent of PFCs in the home came from carpets and carpet treatments.
Upholstery, floor treatments and textiles also bring PFCs into the home. Non-stick pans contribute relatively small amounts. (Figure 1) In some people the indoor environment accounted for half of typical PFOA and PFOS exposure, but for the general population, food accounted for 67-to-84 percent of PFOA exposure and 88-to-99 percent of PFOS exposure. (Haug 2011)
Figure 1. Sources of PFC exposure in a typical U.S. home.
Source: Environmental Working Group, from EPA. http://www.oecd.org/env/48125746.pdf
How long do PFCs remain in the body?
The National Health and Nutrition Examination Survey (NHANES) has been testing for PFCs in the general population since the late 1990s and measuring the chemicals’ half-lives. (The half-life is how long it would take for half of the chemical to be eliminated from the body, assuming no additional exposure.) The half-life of PFOA has been calculated to be 5.4 years, although some studies suggest it may be shorter. (Olsen 2007)
PFOA levels in the U.S. population decreased by more than 40 percent between 2000 and 2010 and likely have continued to drop as the 2015 phase-out date drew nearer. (NHANES 2014) (Figure 2) Sampling by the Norwegian Institute of Public Health shows a very similar trend in Norwegians. (Haug 2009) This study also measured the rapid increase of PFC levels in blood serum that occurred between the mid 1970’s and 2000. (Haug 2009)
Levels of PFOS are higher, but over the last decade the average level in Americans’ blood has dropped from more than 30 parts per billion to fewer than 10 ppb, indicating that the 2002 phase-out is lowering the overall body burden. (Figure 3) (NHANES 2014)