When new acquaintances learn I’m an environmental consultant specializing in water they frequently ask, “Is my water safe to drink?” For almost three decades my stock answer has been that if they are on a public water system there is little worry except for tiny concentrations of disinfection byproducts (DBPs) that form due to interaction of chlorine with natural carbon in the water. We accept this one-in-a-million cancer risk from DBPs as a trade-off to losing one in four young children to dysentery or other water-borne diseases. If you don’t like the chlorine taste, I’d say, get a countertop water filter or simply fill a pitcher with water and let it sit overnight, allowing a few parts per billion DBPs and any residual chlorine to off-gas to the air.
I’m no longer so sure of myself. I thought the public water supply was safe, that we’d dealt with toxic chemicals in public distribution systems years ago. Environmental remediation of groundwater was my profession but I seldom worked on sites with contaminants directly entering public water supplies. I thought situations such as the case of Woburn Massachusetts, portrayed in the 1998 movie A Civil Action, had been cleaned up or were the rare exception to the rule. Organic compounds, heavy metals, and a host of other contaminants are tested by our water providers and the results made public. Compliance with the Safe Drinking Water Act (SDWA) is required and utilities face consequences if they exceed the Maximum Contaminant Levels (MCLs) for contaminants in drinking water. Yet PFAS sample results have yet to appear on the annual water quality reports some large water suppliers, such as Denver Water, provide.
The notion that in 2019, millions of Americans could be served toxic concentrations of chemicals by public water systems has been a jolt to my world view.
PFAS in the Environment
Here in Colorado, at least three aquifers are known to be tainted with per- and polyfluorinated substances (PFAS), a family of synthetic chemicals called “forever chemicals” because they are difficult to treat, don’t easily break down in the environment, and stay in our bodies for years. The combination of PFAS toxicity, environmental persistence, and mobility allow PFAS to migrate for miles in groundwater from source to a water well. This class of chemicals is also used in a wide variety of products we use daily, ranging from dental floss to non-stick skillets, raincoats, and fast food wrappers. In particular, large quantities of PFAS have entered the environment as fire-fighting foams used for petroleum fires. PFAS has also been found in landfill leachate and in wastewater treatment plant effluent discharging to rivers and streams. While many products containing PFAS have been phased out there are still many common items we use daily that expose us to these chemicals.
How PFAS Affects Us
PFAS compounds mimic the fatty acids in our bodies and bind to proteins. They have been found in polar bear blood, detected in 95% of US schoolchildren, and are likely present in your body and mine. PFAS have been linked to kidney, testicular, bladder, and lung cancer, as well as reproductive, cardiovascular and developmental toxicity, and immune system suppression. Because PFAS compounds become part of our tissue, they stay in our system for years after consumption and can accumulate to more than 100 times the concentration originally consumed. Due to the accumulation in our bodies, the EPA has set a non-enforceable “Health Advisory Limit” (HAL) of 70 parts-per-trillion (ppt) for the sum of the two compounds PFOS and PFOA.
PFAS Environmental Distribution
In Colorado, over 100,000 residents of the Fountain Valley near Colorado Springs and in Denver Metro Area’s South Adams County recently learned their municipal drinking water for years contained untreated PFAS concentrations greater than the EPA HALs. In the idyllic foothills of Boulder County domestic well owners near two fire stations where fire-fighting foams were used or stored years ago may have also been exposed to PFAS in groundwater pumped by their private wells. Nationwide PFAS compounds have been discovered in many water systems, however we have no idea how long these contaminants have been in the drinking water because sampling for PFAS only became widespread in about 2015, when the EPA required large water systems to sample for six PFAS compounds. And with thousands of compounds in this class of contaminants, what’s been detected is likely the tip of the iceberg.
As analytical labs have expanded their capabilities and lowered their detection limits, more compounds are being detected. In groundwater that I sampled in December 2018 from Fountain, Colorado, there were 11 different PFAS compounds detected out of the 17 compounds analyzed. When more extensive suites of PFAS compounds are reported by labs, it’s likely that more compounds will be detected in the groundwater there and elsewhere, and the responsible parties will eventually require a plan for environmental remediation.
Environmental Remediation
PFAS environmental remediation is in its infancy. Once upon a time groundwater cleanup was limited to “pump and treat” remediation: pumping contaminated water out of the aquifer, filtering, and then reinjecting the water back into the aquifer. One groundwater cleanup expert compared pump and treat methods to “trying to get soap out of a sponge.” Several decades ago groundwater remediation was revolutionized by “in-situ” cleanup methods – stimulating natural microbes to degrade toxins, or injecting chemicals into an aquifer that break down contaminants in the groundwater. With PFAS, there are no available in-situ treatment methods that have been developed and we are years away from any. We’re back to pump and treat.
The good news is that domestic well owners with PFAS contaminated groundwater can use certain “point of use” home filters that are readily available and easy to install. These are also available for municipal water users.
Regulation
Our public health infrastructure and regulatory institutions are struggling to catch up with this emerging family of contaminants. The EPA has yet to set an enforceable MCL for any PFAS compounds. Without an enforceable standard, responsible parties have been reluctant to pursue PFAS environmental remediation without clear cleanup goals or a regulatory requirement. In the vacuum of federal leadership, many states are setting their own HALs, MCLs, or other cleanup levels for the two main chemicals, PFOS, PFOA, and a hodgepodge of other PFAS compounds. However, there is little consensus on “safe” PFAS drinking water concentrations and some states have established regulatory levels that are less than half the EPA’s HALs. Colorado has recently begun the process of setting standards for surface- and groundwater but limits will not be set until spring of 2020 at the earliest.
This scattershot regulatory environment will create confusion, and likely suspicion, if the EPA eventually sets an MCL at a level higher than many state levels, no matter how sound the supporting science is. Added to this a recent study by the Centers for Disease Control that recommended “safe” concentrations about one tenth of the EPA HALs and the picture becomes even more clouded.
There is currently no coherent national approach to regulating PFAS. The EPA has begun research to establish threshold “reference doses” for PFOS, PFOA, and a handful of other specific compounds, with the stated intent of establishing MCLs for drinking water in the next few years. Meanwhile both of Colorado’s senators have cosponsored federal legislation that would designate all PFAS compounds hazardous substances under CERCLA (Superfund law). The future is uncertain with respect to how these compounds will be regulated and what constitutes a safe concentration in drinking water. It’s as if we’re back in 1980 and are just learning about benzene and TCE. We have a long way to go.
UPDATE 11/20/19 – The Colorado Department of Public Health and Environment is developing standards for PFAS in groundwater and surface-water. The new standards are expected in May of 2020. Additionally PFAS testing is being performed by large water providers.
October 30, 2019
This post is an updated version of an article that originally appeared in the Colorado Environmental Management Society April 2019 Newsletter. No part of this article may be reproduced without attribution to author. Please feel free to link to this post.
See: Horn, Andy, 2019. Is the Water Safe to Drink? Colorado Environmental Management Society Newsletter, April 2019.