Per- and polyfluoroalkyl substances (PFAS) can be ingested through food or water, or encountered in consumer products. The Environmental Working Group, a nonprofit that monitors these chemicals, reports that over 2,800 locations in the United States have found PFAS in their drinking water. Some of these locations are near military bases that used PFAS-containing foams for years during exercises.
Food is considered to be the most primary course of PFAS exposure. PFAS can transfer to food from packaging or from PFAS-contaminated sludge used as a fertilizer on produce and dairy. People who fish or hunt could unknowingly consume meat with high levels of PFAS. After perfluorooctane sulfonate (PFOS) was discovered in rainbow smelt in some lakes, Michigan advised avoiding eating the fish altogether or limiting consumption of any fish caught in those areas in January. A few other states have issued similar warnings after testing fish and game for PFAS compounds.
Some occupations, such as firefighting, painting, carpet laying, and long-term work with ski wax, have a higher risk of PFAS exposure due to the tools they work with, as stated by the Agency for Toxic Substances and Disease Registry, a CDC agency that evaluates potentially toxic chemicals.
Since the early 2000s, companies have stopped using some PFAS, and average blood levels of certain PFAS in residents have fallen since then, according to the CDC. Moreover, companies have started using alternative chemicals that aren’t detected in current testing methods.
According to Jamie DeWitt, an environmental toxicologist at East Carolina University, research indicates that ingested PFAS is absorbed in the intestine and travels to the liver, pass into bile, and be stored in the gallbladder. Mr. DeWitt says that when PFAS contaminated bile enters the small intestine during digestion, PFAS gets reabsorbed into the bloodstream and recirculated. Additionally, instead of being excreted through urine, PFAS can be reabsorbed into the blood from the kidneys. DeWitt said these factors contribute to the long-lasting presence of many PFAS compounds in the body. Another reason is their ability to bind to proteins in the blood.
PFAS have been used since the 1940s. Nearly every U.S. resident has PFAS in their blood, according to the CDC. Companies have halted their use of some PFAS since the 2000s, and blood levels of certain chemicals have decreased since then.
The EPA’s proposed regulations involve limiting two PFAS chemicals found in drinking water—PFOA and PFOS. The EPA would set a limit for PFOA and PFOS of four parts per trillion each in public drinking-water systems.
The EPA claims that, if fully implemented, the rule will prevent thousands of deaths and reduce tens of thousands of serious PFAS-related illnesses.
The agency also stated it would regulate four other PFAS chemicals by requiring treatment if their combined level reaches a specific concentration.
According to Jane Hoppin, an environmental epidemiologist, the potential harm of PFAS chemicals is challenging to assess due to the U.S.’s lack of comprehensive national blood testing for PFAS and the variety of chemicals involved. According to Dr. Hoppin, there isn’t enough research to link any health impacts to specific exposure levels.
Scientists have found associations between PFAS and several health issues, including high cholesterol, decreased immune response to vaccines in children and adults, and an increased risk of kidney cancer, as stated in a 2022 report published by the National Academies of Science, Engineering, and Medicine. The report examined the scientific evidence on these chemicals.
The National Academies report also found studies suggesting links between PFAS and ulcerative colitis, thyroid disease, and breast and testicular cancer, and an increased risk for each disease. Some studies have investigated if PFAS play a role in diabetes, obesity, and fertility disruption in women and men, but there is not enough evidence to establish a connection, according to the report.
Lab studies on animals have supported some of these findings. The CDC has linked PFAS with immune disruption, liver damage, death, and delayed development in newborn animals.
Dr. DeWitt said that the science and medical community understands that these chemicals produce a variety of health outcomes in people and there is enough evidence to show that these chemicals alter bodies to increase the risk of diseases.
PFAS exposure has been linked to an increased risk of high blood pressure during pregnancy and low birth weight, as per the National Academies report. According to Laurel Schaider, an environmental health expert, infants and unborn babies are more vulnerable to harmful chemicals since their brains and critical organs are developing.
PFAS can pass through a pregnant woman’s placenta to the developing fetus and be transmitted to infants through breast milk, the report said.
The CDC states that although there are established tests for PFAS in blood, they are not routinely offered in the United States. Most individuals who have had their blood tested for PFAS have been part of health studies conducted by university scientists or the CDC.
In an ongoing nationwide study, the CDC and independent research groups are investigating the link between exposure to PFAS through drinking water and health issues such as thyroid or liver disease, or high cholesterol. These studies are testing the blood of participants who live in eight regions where PFAS has been found in drinking-water systems.
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