If you heard the chemical names PFOA or PFOS, you may not recognize them. They are better known by the products in which they are found – Teflon™, Gore-Tex™, Scotch Guard™ and many other commercial goods. Over the past ten years, these chemicals have become recognized as serious environmental pollutants and human health hazards.
What Are PFOA and PFOS?
Perfluorooctanoic acid, also known as PFOA or C8, and perfluorooctanecsulfonic acid, or PFOS, are synthetic fluorosurfactants. They have been manufactured since the 1940s and used in the synthesis of fluoropolymers such as Teflon™ coatings, Teflon™ tape, stain-resistant chemicals for carpeting and clothing, and waterproofing on fabric and paper. The primary manufacturer, 3M, first became aware of the environmental concerns in 1993 but continued production until they announced a phase-out in May 2000. 3M stopped production in 2002 following concerns raised by the U.S. Environmental Protection Agency (USEPA) 1. Eight other companies agreed to phase out PFOA and PFOS production domestically by 2015, although the chemicals are still made in many other countries, especially China. In fact, some of the highest global water concentrations are measured off the coast of China, in South Korea and down to the Philippines.
Why Are These Chemicals Considered So Dangerous?
Unfortunately, PFOA and PFOS tend to persist in the environment almost indefinitely. Not only do they endure, but they also are resistant to recognized environmental degradation processes. They are highly mobile and have been transported around the world by air, in water, and as solid waste. These chemicals possess a unique trait of repelling both water and oil – meaning they are nearly insoluble. They are found throughout the globe.
Both chemicals, part of a larger group of fluoropolymers, have been found on every continent and in every major body of water. They have been measured in the blood of Atlantic salmon, swordfish, mullet, gray seals, cormorants, polar bears, brown pelicans, sea turtles, bald eagles and sea lions – in other words, everywhere 2.
In commercial goods, they have been used on the coating for microwaveable popcorn bags, fast food wrappers, pizza box liners, candy wrappers, Teflon™ pipe seal tape, and expandable foam fire-fighting chemicals. Toxicologists estimate that coated popcorn bags could account for as much as one-fifth of human exposure.
How Do They Enter the Environment?
In North Bennington, Vermont, ChemFab operated a small plant that used PFOA to apply Teflon™ to tarps. These tarps, among other uses, formed the rooftop of Mile High Stadium in Denver. In the process, the PFOA was baked off at 400 degrees in the final step, discharging the chemical to the air 3.
In Hoosick Falls, New York, seven miles from the ChemFab plant, the town tested its municipal water supply and found PFOA at a concentration of 0.54 parts-per-billion (ppb) in town drinking water in November 2014. By December 2015, the concentration had increased to 0.66 ppb. The next month, the USEPA sent letters to every resident warning them not to drink, cook with, or bathe in water from the town water supply.
PFOA has been detected in the blood at very low levels, of more than 98% of the general U.S. population. It is present at much higher concentrations in and around plants where it was synthesized or used in manufacturing of products 4. A typical pathway identified processed wastewater from a perfluorochemical manufacturer being discharged to a municipal water treatment facility. Sludge, a byproduct of the wastewater treatment process, was given to farmers to fertilize fields; their cattle fed on the grass; and the beef products entered the human food chain. The half-life of these chemicals in humans is reported to be two to four years 5. So even if all use were stopped globally, it would take decades for the concentration to drop to a safe level, given that very elevated levels in water will take time to degrade.
How Are These Chemicals Harmful to People?
Epidemiologists have determined that there is an association between PFOA and seven adverse health outcomes: kidney cancer, testicular cancer, ulcerative colitis, liver disease, thyroid disease, elevated cholesterol, birth defects, and pregnancy-induced hypertension. Currently, there are no federal drinking water standards for PFOA or PFOS. In 2009, the USEPA set a health advisory level of 0.4 ppb; and in late 2016, lowered it to 0.07 ppb – a six-fold decrease. Some states, such as Vermont, have set even lower levels.
So What Can Be Done?
PFOA and PFOS can be removed from water using an activated carbon point-of-use system – through a device installed in the home or at the water supply. A high-pressure reverse osmosis treatment system is a second, but far more costly alternative. There are many products on the market that claim to remove these chemicals. Only those carbon treatment systems certified by NSF/ANSI will remove greater than 95% of the chemicals down to the USEPA advisory level. One limiting factor still remains – how long will the systems last?
HETI:..A Resource for Information and Testing
If there are questions about the health effects of PFOA and PFOS, how to find out if drinking water is safe, and what to do if the levels are elevated, HETI can help. Our experienced engineers deal with complex issues such as these on a daily basis for a wide range of clients.
1 EPA Fact Sheet − PFOA & PFOS Drinking Water Advisory, November 2016
2 “The Lawyer Who Became DuPont’s Worst Nightmare”, 2016
3 Schroeder, Bond & Foley, 2017
4 Calafat, Wong & Kuklenyik, 2007
5 “EPA Finds Record PFOS, PFOA Levels in Alabama Grazing Fields”, 2016
To find out more about HETI’s environmental and industrial hygiene services, please contact us.
Scott Herzog, CIH
Environmental Health & Safety Practice Leader