I live in New York City; Manhattan, to be specific. When one of my eco-conscious childhood friends came to visit, we compared notes on the fundamental stuff of life: water.

She lived in a rural part of Arizona and worried often about her water quality. I felt like the lucky one. New York City water is renowned for its quality. Each day, more than a billion gallons of fresh, clean water arrives from large upstate reservoirs, some more than 125 miles from the city, to the taps of nine million customers throughout New York state. To ensure safety, scientists test the city drinking water hundreds of times each day, collecting samples from the reservoirs, aqueducts, treatment facilities, and 1,000 street-side sampling stations throughout the five boroughs (Drinking Water, 2020).

My friend had moved west from the New York suburbs to find a greener environment. She pointed to the noise, dust, and recirculated air in my office building. She talked up the medicinal qualities of plants in her garden.

But the conversation ended with her saying, “I really have to do something about my water.”   

How safe is your water?  

The United States generally has safe drinking water supplies. But problems crop up, especially in rural low-income areas like my friend’s, and affect millions of Americans every year, according to a 2018 study (Allaire et al., 2018). Contaminated water may cause an upset stomach or create serious dangers, including increased risk for certain cancers and neurological problems.

Maura Allaire, a water economist at the University of California, Irvine, lived near Flint, Michigan, in 2015. That’s when we all learned that Flint residents – and, most distressingly, its children - were being essentially doused with lead. Wondering if water quality was safe elsewhere in the U.S., she examined Environmental Protection Agency data dating back 34 years. Some areas showed high lead levels; others show high levels of coliform bacteria, a sign of more bacteria, as well as nitrates, arsenic, and other contaminants.

Endocrine system disruptors

Those contaminants include chemicals that alter our hormone levels, an international team led by Leonardo Trasande, a pediatrician at New York University, reported in July, after examining new research (Kahn et al., 2020).

The problem isn’t new. The Endocrine Society commissioned a study in 2015 identifying 15 problems linked to various chemicals that disrupt the normal functioning of the endocrine system (Gore et al., 2015). Two years later, the United Nations (UN) published its own list of 45 culprits, including chemicals in pesticides that enter the water.

But now scientists know more about the dangers of polyfluoroalkyl and perfluoroalkyl substances (PFAS), which weren’t included in the Endocrine Society and UN publications. Introduced more than 60 years ago, PFAS are stain- and water-repellant chemicals found in cookware, water-repellent clothes, and stain-resistant fabric and carpets. The combination of exposure to PFAS and other chemicals can make men infertile, Trasande’s team wrote.

Several new studies link brain-related problems like attention deficit disorder to flame retardants and chemicals in certain pesticides. "Our understanding of endocrine disruptors has evolved, but the regulations in place to protect against them have not," he said, "What's needed are more rigorous tests of commercial chemicals that account for these complexities." (Trasande, 2019).

The Problem with PFAS

PFAS infiltrate our freshwater, and also the air, household dust, food, and soil. They accumulate in the body over years, affecting the blood, the liver, and other organs. To call them ubiquitous is an understatement: The U.S. National Health and Nutrition Examination Survey have found PFAS in 97 percent of human blood samples (Lewis et al., 2015).

Because PFAS affects the immune system, it may make vaccines for measles, flu, diphtheria, and tetanus less effective. One study revealed that about 600 teens from the Faroe Islands who had been immunized against those illnesses and also exposed to PFAS at a young age lacked immunity (Grandjean et al., 2017).

Although the EPA has set limits on the amount of PFAS in public water, millions of Americans people are exposed to too much. In a 2016 study of 36,000 water samples, researchers discovered perfluorooctanesulfonic and perfluorooctanoic acid, two examples of PFAS, in sources of public water serving six million Americans altogether.

The highest concentrations of the chemicals occurred in Newark, Delaware; and Warminster, Pennsylvania. The same team found that some 16.5 million Americans, particularly those who lived near industrial sites, military bases, or wastewater treatment plants, drank water with one of six types of PFAS contamination at or above the EPA’s safety limit (Zhang et al., 2017).

Practical solutions

Should you give up on public water? No. You’ll need to test private well water regularly, since it is affected by maintenance and what people are doing nearby. Public water is still probably your safest bet, especially if you live in any of these cities that have consistently excellent water-quality ratings: New York, Chicago, Denver and Fort Collins, Oklahoma City, and Louisville. Small water systems in rural areas can’t afford the best treatment technology, so you might push leaders in your community to buy treated water from larger utilities.

If you have reason for worry, invest in a quality water filtering system. Under-the-sink reverse osmosis filters reduced PFAS levels by 94 percent in a recent study in North Carolina (Herkert et al, 2020). You might pay from $200 to $400.

Less expensive activated-carbon filters in pitcher, countertop, refrigerator, and faucet-mounted systems are less reliable. They removed 73 percent of PFAS contaminants, on average, in the North Carolina study, but results varied greatly. Some filters removed all chemicals; others none, and the research team couldn’t find evidence that one brand was better than another. Don’t forget to change your filter as instructed! 

Whole-house systems using activated carbon filters were also a mixed bag. In four of the six systems tested, levels of some contaminants actually increased after filtration. In addition, these systems removed disinfectants in city water, leaving home pipes vulnerable to bacteria.

Other steps you can take immediately to safeguard your and your family’s health:

  • Monitor your water quality by calling the Safe Drinking Water Hotline at 800-426-4791, or visit the Environmental Protection Agency (EPA) lab network online.
  • Use cold water from your taps in case your hot water pipes are introducing more chemicals, which can happen because the chemicals are more easily dissolved and transported by heat.
  • For more about what needs to be done, read Leonardo Trasande’s Sicker, Fatter, Poorer: The Urgent Threat of Hormone-Disrupting Chemicals to Our Health and Future . . . and What We Can Do About It.

In the meantime, I continue to be grateful for New York’s commitment to providing citizens like me with quality drinking water. Rural Arizona has its charms, but each day when I twist the tap handle, I’m grateful to be here.


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Danso D, Schmeisser C, Chow J, et al. New Insights into the Function and Global Distribution of Polyethylene Terephthalate (PET)-Degrading Bacteria and Enzymes in Marine and Terrestrial Metagenomes. Applied and environmental microbiology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5881046/. Published April 2, 2018.

Drinking Water. Drinking Water - DEP. https://www1.nyc.gov/site/dep/water/drinking-water.page. Accessed September 8, 2020.

Gore AC, Chappell VA, Fenton SE, et al. Executive Summary to EDC-2: The Endocrine Society's Second Scientific Statement on Endocrine-Disrupting Chemicals. https://academic.oup.com/edrv/article/36/6/593/2354738. Published December 1, 2015.

Grandjean P, Heilmann C, Weihe P, Nielsen F, Mogensen UB, Budtz-Jørgensen E. Serum Vaccine Antibody Concentrations in Adolescents Exposed to Perfluorinated Compounds. Environ Health Perspect. https://pubmed.ncbi.nlm.nih.gov/28749778/ Published 2017 Jul 26, 2017.

Herkert N, Merrill J, Peters C, Bollinger D, Zhang S, Hoffman K, Ferguson P, Knappe D, and. Stapleton H. Assessing the Effectiveness of Point-of-Use Residential Drinking Water Filters for Perfluoroalkyl Substances (PFASs)Environmental Science & Technology Letters https://pubs.acs.org/doi/10.1021/acs.estlett.0c00004 Published Feb 5, 2020.

Kahn LG, Philippat C, Nakayama SF, Slama R, Trasande L. Endocrine-disrupting chemicals: implications for human health. Lancet Diabetes Endocrinolhttps://pubmed.ncbi.nlm.nih.gov/32707118/ Published August 8, 2020.

Kassotis CD, Vandenberg LN, Demeneix BA, Porta M, Slama R, Trasande L. Endocrine-disrupting chemicals: economic, regulatory, and policy implications. Lancet Diabetes Endocrinol. https://pubmed.ncbi.nlm.nih.gov/32707119/  Published August 8, 2020.

Lewis RC, Johns LE, Meeker JD. Serum Biomarkers of Exposure to Perfluoroalkyl Substances in Relation to Serum Testosterone and Measures of Thyroid Function among Adults and Adolescents from NHANES 2011-2012. International journal of environmental research and public health. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483690/. Published May 29, 2015.

Trasande, Leonardo. SICKER, FATTER, POORER: the Urgent Threat of Hormone-Disrupting Chemicals to Our Health and ... Future - and What We Can Do about It. MARINER Books; 2019.

UN List of Identified Endocrine Disrupting Chemicals. https://www.chemsafetypro.com/Topics/Restriction/UN_list_identified_endocrine_disrupting_chemicals_EDCs.html. Published August 20, 2018. Accessed August 11, 2020.

Varshavsky JR, Morello-Frosch R, Woodruff TJ, Zota AR. Dietary sources of cumulative phthalates exposure among the U.S. general population in NHANES 2005-2014. Environ Int. 2018;115:417-429. doi:10.1016/j.envint.2018.02.029 https://pubmed.ncbi.nlm.nih.gov/29605141/

Wehrli A. The Cleanest (Drinking) Water In The US Is In These 10 Cities. TheTravel. https://www.thetravel.com/cleanest-drinking-water-us-cities/. Published March 31, 2020.

Zhang X, Lohmann R, Dassuncao C, et al. Source attribution of poly- and perfluoroalkyl substances (PFASs) in surface waters from Rhode Island and the New York Metropolitan Area. Environmental science & technology letters. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310642/. Published September 13, 2016.