Houston, Texas, USA : Widely used household and industrial chemicals may harm the kidneys, researchers say. These manufactured chemicals, called per- and polyfluoroalkyl substances, or PFAS, are not biodegradable. People are exposed to them through contaminated soil, food, water and air.
Certain highly pervasive environmental pollutants may have a variety of negative effects on kidney health, according to an analysis of all relevant studies published on this topic to date. The findings, which appear in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN), point to the need for additional research to clarify and address these effects.
Per- and polyfluoroalkyl substances (PFAS) are a large group of manufactured non-biodegradable compounds used in industrial processes and consumer products, and they are everywhere in the environment. Humans are exposed to PFAS through contaminated soil, food, water, soil, and air. Recently, they have been detected on military bases, where they are used in aqueous fire-fighting foams, as well as in public water supplies from industrial contamination and in agricultural and crop products.
In an analysis of all relevant studies, exposure to environmental toxins called per- and polyfluoroalkyl substances was linked to worse kidney function and other signs of kidney damage.
To investigate whether PFAS exposure may be affecting kidney health, John Stanifer, MD, MSc (Duke University) and his colleagues searched the medical literature for relevant studies. “The kidneys are very sensitive organs, particularly when it comes to environmental toxins that can get in our bloodstream. Because so many people are now exposed to these PFAS chemicals, and to the newer, increasingly-produced alternative PFAS agents such as GenX, it is critical to understand if and how these chemicals may be contributing to kidney disease,” he said.
In the 74 studies identified, there were many adverse outcomes linked to PFAS exposure, including worse kidney function, derangements in the proximal tubules (the resorptive structure of the kidney), and dysregulated metabolic pathways linked to kidney disease. It was also particularly concerning that children are exposed to these chemicals to a greater extent than adults.
“By searching all the known studies published on the topic, we concluded that there are several potential ways in which these chemicals can cause kidney damage,” said Dr. Stanifer. “Further, we discovered that there have already been multiple reports suggesting that these chemicals are associated with worse kidney outcomes.”
Study co-authors include Heather Stapleton, PhD; Tomokazu Souma, MD, PhD; Ashley Wittmer, BS; Xinlu Zhao, BS; and L. Ebony Boulware, MD, MPH.
Disclosures: The authors reported no financial disclosures.
The article, titled “Perfluorinated Chemicals as Emerging Environmental Threats to Kidney Health: A Scoping Review,” appeared in the Clinical Journal of the American Society of Nephrology.
he U.S. Environmental Protection Agency (EPA) has more on PFAS below:
Basic Information on PFAS
What are PFAS?
Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s. PFOA and PFOS have been the most extensively produced and studied of these chemicals. Both chemicals are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. There is evidence that exposure to PFAS can lead to adverse human health effects.
PFAS can be found in:
- Food packaged in PFAS-containing materials, processed with equipment that used PFAS, or grown in PFAS-contaminated soil or water.
- Commercial household products, including stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams (a major source of groundwater contamination at airports and military bases where firefighting training occurs).
- Workplace, including production facilities or industries (e.g., chrome plating, electronics manufacturing or oil recovery) that use PFAS.
- Drinking water, typically localized and associated with a specific facility (e.g., manufacturer, landfill, wastewater treatment plant, firefighter training facility).
- Living organisms, including fish, animals and humans, where PFAS have the ability to build up and persist over time.
Certain PFAS chemicals are no longer manufactured in the United States as a result of phase outs including the PFOA Stewardship Program in which eight major chemical manufacturers agreed to eliminate the use of PFOA and PFOA-related chemicals in their products and as emissions from their facilities. Although PFOA and PFOS are no longer manufactured in the United States, they are still produced internationally and can be imported into the United States in consumer goods such as carpet, leather and apparel, textiles, paper and packaging, coatings, rubber and plastics.
Why are PFAS important?
PFAS are found in a wide range of consumer products that people use daily such as cookware, pizza boxes and stain repellants. Most people have been exposed to PFAS. Certain PFAS can accumulate and stay in the human body for long periods of time. There is evidence that exposure to PFAS can lead to adverse health outcomes in humans. The most-studied PFAS chemicals are PFOA and PFOS. Studies indicate that PFOA and PFOS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals. Both chemicals have caused tumors in animals.
The most consistent findings are increased cholesterol levels among exposed populations, with more limited findings related to: low infant birth weights, effects on the immune system, cancer (for PFOA), and thyroid hormone disruption (for PFOS).
What is the difference between PFOA, PFOS and GenX and other replacement PFAS?
PFOA and PFOS are made up of “chains” of eight carbon atoms that are attached to fluorine and other atoms. Replacement chemicals, like GenX, tend to have fewer carbon atoms in the chain, but have many similar physical and chemical properties as their predecessors (e.g. they both repel oil and water). Industries in the United States have phased out production of PFOA and PFOS because of concerns about health risks to humans and have been using replacement PFAS, such as GenX. There is a substantial body of knowledge for managing risk from PFOS and PFOA, but much less knowledge about the replacement PFAS.
How are people exposed to PFAS?
There are a variety of ways that people can be exposed to these chemicals and at different levels of exposure. For example, people can be exposed to low levels of PFAS through food, which can become contaminated through:
- Contaminated soil and water used to grow the food,
- Food packaging containing PFAS, and
- Equipment that used PFAS during food processing.
People can also be exposed to PFAS chemicals if they are released during normal use, biodegradation, or disposal of consumer products that contain PFAS. People may be exposed to PFAS used in commercially-treated products to make them stain- and water-repellent or nonstick. These goods include carpets, leather and apparel, textiles, paper and packaging materials, and non-stick cookware.
People who work at PFAS production facilities, or facilities that manufacture goods made with PFAS, may be exposed in certain occupational settings or through contaminated air.
Drinking water can be a source of exposure in communities where these chemicals have contaminated water supplies. Such contamination is typically localized and associated with a specific facility, for example,
an industrial facility where PFAS were produced or used to manufacture other products, or
an oil refinery, airfield or other location at which PFAS were used for firefighting.
PFOA, PFOS, and GenX have been found in a number of drinking water systems due to localized contamination. You can view more information about exposures to PFAS through drinking water on our Drinking Water Health Advisories for PFOA and PFOS page.
Are there health effects from PFAS?
There is evidence that exposure to PFAS can lead to adverse health outcomes in humans. If humans, or animals, ingest PFAS (by eating or drinking food or water than contain PFAS), the PFAS are absorbed, and can accumulate in the body. PFAS stay in the human body for long periods of time. As a result, as people get exposed to PFAS from different sources over time, the level of PFAS in their bodies may increase to the point where they suffer from adverse health effects.
Studies indicate that PFOA and PFOS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals. Both chemicals have caused tumors in animal studies.
The most consistent findings from human epidemiology studies are increased cholesterol levels among exposed populations, with more limited findings related to: infant birth weights, effects on the immune system,
cancer (for PFOA), and thyroid hormone disruption (for PFOS).