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The Environmental Protection Agency is warning that two nonstick and stain-resistant compounds found in drinking water pose health risks even at levels so low they cannot currently be detected.

The two compounds, known as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), have been voluntarily phased out by U.S. manufacturers, but there are a limited number of ongoing uses and the chemicals remain in the environment because they do not degrade over time. The compounds are part of a larger cluster of "forever chemicals" known as PFAS that have been used in consumer products and industry since the 1940s.

Perfluoroalkyls are a family of human-made chemicals that do not occur naturally in the environment. The EPA on Wednesday issued nonbinding health advisories that set health risk thresholds for PFOA and PFOS to near zero, replacing 2016 guidelines that had set them at 70 parts per trillion. The chemicals are found in products including cardboard packaging, carpets and firefighting foam.

These toxic compounds are associated with a number of diseases and chronic illnesses.


Exposure to perfluoroalkyl compounds is widespread. PFOA, PFOS, PFNA, and PFHxS were detected in 95–100% of samples of people’s blood in 1999–2000 and 2003–2004. More recent monitoring data still show widespread exposure; however, the levels of these substances in people’s blood appear to be declining. You may be exposed to perfluoroalkyls from the air, indoor dust, food, water, and various consumer products. You may also be exposed to perfluoroalkyls from treated carpets and upholstery; this is especially true for children. The greatest source of exposure to PFOA and

PFOS for toddlers and children is hand-to-mouth activities from treated carpets.

Several states have set their own drinking water limits to address PFAS contamination that are far tougher than the federal guidance. The toxic industrial compounds are associated with serious health conditions.

"People on the front-lines of PFAS contamination have suffered for far too long," EPA Administrator Michael Regan said in a statement. "That's why EPA is taking aggressive action as part of a whole-of-government approach to prevent these chemicals from entering the environment and to help protect concerned families from this pervasive challenge."

PFAS are used in nonstick frying pans, water-repellent sports gear, stain-resistant rugs, cosmetics and countless other consumer products. The chemical bonds are so strong that they don't degrade or do so only slowly in the environment and potentially remain in a person's bloodstream indefinitely. The revised health guidelines are based on new science and consider lifetime exposure to the chemicals, the EPA said. Officials are no longer confident that PFAS levels allowed under the 2016 guidelines "do not have adverse health impacts,'' an EPA spokesman said.

While the new guidelines set acceptable risk below levels that can currently be measured, as a practical matter EPA recommends that utilities take action against the chemicals when they reach levels that can be measured — currently about four parts per trillion, a senior administration official told reporters Tuesday night.

The EPA said it expects to propose national drinking water regulations for PFOA and PFOS later this year, with a final rule expected in 2023. In a related development, the EPA said that for the first time it is issuing final health advisories for two chemicals that are considered replacements for PFOA and PFOS. One group is known as GenX chemicals, while the other is known as PFBS. Health advisories for GenX chemicals were set at 10 parts per trillion, while PFBS was set at 2,000 parts per trillion.

The agency said the new advisories provide technical information that federal, state and local agencies can use to inform actions to address PFAS in drinking water, including water quality monitoring, use of filters and other technologies that reduce PFAS and strategies to reduce exposure to the substances.

"The science is clear: These chemicals are shockingly toxic at extremely low doses,'' added Erik Olson, senior strategic director for health and food at the Natural Resources Defense Council. He called on the EPA to regulate all PFAS chemicals "with enforceable standards as a single class of chemicals."

The EWG estimates that more than 200 million Americans are drinking water contaminated with PFAS.


Perfluoroalkyls can enter your body if you breathe air, eat food, or drink water containing them. We do not know how much will enter your body through your lungs or your digestive tract. If your skin comes into contact with dusts or aerosols of perfluoroalkyl or with liquids containing perfluoroalkyls, it is possible that a small amount may enter the body through your skin.

Once in your body, perfluoroalkyls tend to remain unchanged for long periods of time. The most commonly used perfluoroalkyls (PFOA and PFOS) stay in the body for many years. It takes approximately 4 years for the level in the body to go down by half, even if no more is taken in. It appears that, in general, the shorter the carbon-chain length, the faster the perfluoroalkyl leaves the body. Perfluoroalkyls leave the body primarily in the urine.

Gastrointestinal Elimination of Perfluorinated Compounds Using Cholestyramine and Chlorella pyrenoidosa

While there has been little attention in scientific research to clinical detoxification, there is a clear need to develop methods to reduce the body burdens of PFCs and other persistent toxicants in order to preclude adverse outcomes. There has been minimal study on means to specifically facilitate removal of PFCs from the human body, and recent research exploring the potential elimination of these compounds through skin depuration demonstrated a lack of success. Another potential approach is to give oral agents which reduce PFC absorption in the GI tract and/or increase toxicant excretion via blocking of reabsorption of toxics in the enterohepatic pathway. The most studied of these oral detoxifying agents has been the bile sequestering agent cholestyramine (CSM). Other agents proposed for oral detoxification of persistent toxics include clay and zeolite compounds, supplements of the algae Chlorella pyrenoidosa (CP), and vegetable fibers like Psyllium husks.

Chlorella is a green unicellular alga that is commercially produced and distributed worldwide as a dietary supplement. Chlorella products contain numerous nutrients and vitamins, including D and B12, that are absent in plant-derived food sources. Chlorella contains larger amounts of folate and iron than other plant-derived foods. Chlorella supplementation to mammals, including humans, has been reported to exhibit various pharmacological activities, including immunomodulatory, antioxidant, antidiabetic, antihypertensive, and antihyperlipidemic activities. Meta-analysis on the effects of Chlorella supplementation on cardiovascular risk factors have suggested that it improves total cholesterol levels, low-density lipoprotein cholesterol levels, systolic blood pressure, diastolic blood pressure, and fasting blood glucose levels but not triglycerides and high-density lipoprotein cholesterol levels. These beneficial effects of Chlorella might be due to synergism between multiple nutrient and antioxidant compounds. However, information regarding the bioactive compounds in Chlorella is limited.

How to Reduce PFOA/PFOS in Drinking Water

To comply with the standards, a device must reduce PFOA and PFOS concentrations in water to below the 70 parts per trillion (ppt) health advisory level set by the U.S. Environmental Protection Agency (EPA).

Devices must also comply with material and physical requirements of NSF/ANSI 53: Drinking Water Treatment Units – Health Effects or NSF/ANSI 58: Reverse Osmosis Drinking Water Treatment Systems. Certified products must be retested periodically and manufacturing facilities must be inspected every year, which ensures products continue to meet all requirements.

In accordance with these standards, NSF verifies that:

  • The contaminant reduction claims for PFOA and PFOS shown on the label are true.

  • The system does not add anything harmful to the water.

  • The system does not leak.

  • The product labeling, advertising and literature are not misleading.

To make a PFOA/PFOS reduction claim, a water filter must be able to reduce these chemicals to below the EPA healthy advisory limit of 70 parts per trillion. Certified products must be retested periodically and manufacturing facilities must be inspected every year, which ensures products continue to meet all requirements.

To find products that are certified by NSF to reduce PFOA/PFOS in drinking water, see NSF’s certification listings.



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