PFAS the “Forever Chemicals”, Immunotoxicity, and Covid-19
PFAS, otherwise known as perfluorinates or polyfluoroalkyl substances, are also termed “the forever chemicals“ due to their very long half-lives in the human body. There are over 200 different PFAS, but 31 common compounds have been identified and are tested for in humans. (see Lab Testing below)
In a study of urinary excretion in a background population in China, half-lives (the period of time it takes for 50% of a compound to be eliminated from the body) for PFHxS, PFOS, and PFOA were 7.7, 6.2, and 2.1 for reproductive age females. Half-lives were significantly different for males and menopausal females: 35, 27, and 2.6 years. The difference is believed to be due to the loss of PFAS in menstrual fluid, gestational transfer and breastmilk in reproductive-age women.
(Zhang Y, Beesoon S, Zhu L, Martin JW. Biomonitoring of perfluoroalkyl acids in human urine and estimates of biological half-life. Environ Sci Technol. 2013 Sep 17;47(18):10619-27. doi: 10.1021/es401905e. Epub 2013 Aug 27. PMID: 23980546.)
Exposure to PFAS has been correlated with many different health conditions--kidney and testicular cancer, low birth weight, thyroid disease, decreased sperm quality, cancer, thyroid disease, asthma, ulcerative colitis, arthritis, cardiovascular disease, reproductive damage and immunotoxicity. Areas with high levels of perfluorinates in drinking water have shown increased incidence of diabetes, cerebrovascular diseases, myocardial infarction, and Alzheimer’s disease in both sexes and kidney cancer, breast cancer, and Parkinson’s disease in females.
(Bonato M, Corrà F, Bellio M, et al. PFAS Environmental Pollution and Antioxidant Responses: An Overview of the Impact on Human Field. Int J Environ Res Public Health. 2020;17(21):8020. Published 2020 Oct 30.)
PFAS and Covid-19
Also, a study published last year, December 2020 in the journal PLoS, indicates that a specific perfluorinate may increase risk for more severe cases of Covid-19 pneumonia.
“It’s probably what’s in the lungs that counts because that’s where the big Covid battle is fought,” said Philippe Grandjean, the principal author of the study looking at Covid-19 hospitalized patients and their PFAS levels. Grandjean’s study involved 323 patients with Covid-19, 215 of whom were hospitalized. The researchers analyzed the blood of these patients for the presence of five PFAS compounds known to be immunotoxic and found that only perfluorobutanoic acid (PFBA), was associated with the severity of the disease. More than half of those seriously ill with Covid-19 had elevated PFBA levels in their plasma, while less than 20 percent of those with mild illness had elevated levels of the chemical.
(Grandjean P, Timmermann CAG, Kruse M, Nielsen F, Vinholt PJ, Boding L, Heilmann C, Mølbak K. Severity of COVID-19 at elevated exposure to perfluorinated alkylates. PLoS One. 2020 Dec 31;15(12):e0244815. doi: 10.1371/journal.pone.0244815. PMID: 33382826)
Of the study population, 215 had been hospitalized, and 53 (16%) had been admitted to intensive care and/or eventually died. Those with elevated plasma levels of perfluorobutanoic acid (PFBA) plasma levels were 2.19 times (95% confidence interval 1.39–3.46) more likely to have severe disease. Among those hospitalized, individuals with higher levels of PFBA were 5.18 times more likely to be admitted to intensive care or to die from Covid-19 pneumonia. In tissue samples from autopsies, PFBA was the only PFAS that substantially accumulated in the lungs.
In a press briefing that same month, Environmental Working Group scientists presented research on the immunotoxicity of PFAS as a class of chemicals resulting in reduced antibody response to antigens, reduced NK cell activity, and increased airway hypersensitivity (PFOA).
(https://www.ewg.org/news-insights/news/pfas-chemicals-harm-immune-system-decrease-response-vaccines-new-ewg-review-0)
Perfluorinates are ubiquitous in the U.S. population: in the NHANES study of U.S. adolescents and adults in2003-2004, 4 perfluorinates (PFOS, PFOA, PFHxS, and PFNA) were detected in greater than 98% of all 2,094 participants. Although levels for three of the perfluorinate compounds had dropped due to a phasing out of their production (32% lower for PFOS, 25% lower for PFOA, 10% lower for PFHxS) levels of the fourth chemical, PFNA, had doubled since the NHANES 1999–2000 report (p < 0.001).
(Calafat AM, Wong LY, Kuklenyik Z, Reidy JA, Needham LL. Polyfluoroalkyl chemicals in the U.S. population: data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 and comparisons with NHANES 1999- 2000. Environ Health Perspect. 2007;115(11):1596-1602.)
Exposure Sources of PFAS
Where has this universal exposure to perfluorinates come from?
As of July 2019, the Environmental Working Group and the Social Science Environmental Health Research Institute at Northeastern University have identified 712 sites in 49 states with PFAS contamination. These include public water systems serving at least 19 million people, and unreleased EPA data suggest as many as 110 million individuals may have PFAS-contaminated drinking water.
(https://www.ewg.org/news-insights/news-release/new-pfas-detections-reported-90-additional-army-installations)
While drinking water sources of perflourinates in the U.S. and other countries, like Italy have been identified in multiple cities and towns, the other major exposure source of PFAS appears to be fish. Christensen et al., found elevated concentrations of serum PFAS among high-frequency fish consumers in the U.S. National Health and Nutrition Exam Survey between 2007 and 2014. The European Food Safety Authority (EFSA) -the equivalent of the US FDA- recently estimated that “fish and other seafood” account for up to 86% of dietary PFAS exposure in adults.
(Sunderland EM, Hu XC, Dassuncao C, Tokranov AK, Wagner CC, Allen JG. A review of the pathways of human exposure to poly- and perfluoroalkyl substances (PFASs) and present understanding of health effects. J Expo Sci Environ Epidemiol. 2019;29(2):131-147.)
Lab Testing for PFAS
Testing for PFAS in areas with known drinking water contamination is often done by local health departments. If not available, there are two laboratories that will test for a specific panel of 31 required PFAS compounds: Vista Analytical- https://www.vista-analytical.com/pfas and NMS Labs- https://www.nmslabs.com/tests/3427SP#analytes. The New Hampshire Dept of Health and Human Services website has a comparison of both tests and cost- https://www.dhhs.nh.gov/dphs/pfcs/blood-testing.htm)
Reducing Body Burden of PFAS
PFAS are not readily eliminated from the body through feces, urine, or sweat. The only potential evidence for decreasing body burden of PFAS are routine phlebotomy and cholestyramine. Routine phlebotomy (500 ccs of whole blood every 56 days or longer) was utilized in a family that had been found to have high serum levels of the perfluorochemicals: PFHxS, PFOA PFOS, and PFNA. Follow-up over a 4-year period showed a significant reduction in all 3 compounds in both parents and 4 children.
(Genuis SJ, Liu Y, Genuis QI, Martin JW. Phlebotomy treatment for elimination of perfluoroalkyl acids in a highly exposed family: a retrospective case-series. PLoS One. 2014 Dec 12;9(12):e114295. doi: 10.1371/journal.pone.0114295. PMID: 25504057)
Another group of 8 patients with elevations of the same PFAS were given cholestyramine, resulting in a significant reduction of serum PFHxS, PFOA, PFOS and an increase of fecal excretion of the same compounds in all 8 individuals.
(Genuis SJ, Curtis L, Birkholz D. Gastrointestinal Elimination of Perfluorinated Compounds Using Cholestyramine and Chlorella pyrenoidosa. ISRN Toxicol. 2013 Sep 9; 2013:657849. doi: 10.1155/2013/657849. PMID: 24106616