Massachusetts takes steps toward protecting residents from harmful chemicals in drinking water

Why the state’s new proposed rule to regulate PFAS contaminants is good for public health

By Laurel Schaider, PhD and Kathryn Rodgers, MPH

In December, the Massachusetts Department of Environmental Protection (MassDEP) released a proposed rule that would regulate PFAS contaminants in the state’s drinking water supplies. We applaud this effort as a critical step toward protecting Massachusetts residents from these toxic and persistent chemicals.

Massachusetts is one of several states that have taken the lead in recent years to address what has become a national PFAS contamination crisis. Given inaction at the federal level to protect our drinking water supplies, we hope more states will follow suit. Access to safe drinking water, free of toxic chemicals, is a fundamental human right.

PFAS (per- and polyfluoroalkyl substances) are a class of chemicals that are widely used in consumer products and firefighting foams. As scientists and environmental health experts, we are concerned about the public’s exposure because some PFAS have been linked to cancers, immunotoxicity in children, thyroid disease, reproductive problems, altered mammary gland development, and other health effects. Silent Spring Institute is currently leading several major studies on PFAS, aimed at better understanding how we are exposed and effects on our health.

These chemicals are also extremely persistent. Once released into the environment, they don’t break down. An estimated 100 million people in the United States are now exposed to drinking water contaminated with PFAS. According to MassDEP, 21 public water supplies have had PFAS levels above the proposed standard, and that number is likely to grow as more water supplies are required to test their water.

The Massachusetts rule would establish a drinking water standard of 20 parts per trillion (ppt) for the sum of six different PFAS chemicals. Compared with the U.S. Environmental Protection Agency’s (EPA) non-enforceable health advisory level of 70 ppt for two PFAS combined (PFOA and PFOS), MassDEP’s rule is significantly more health protective. Under the rule, water suppliers will be required to conduct routine testing and treat their drinking water should the levels exceed the limit.

In comments we shared with MassDEP at a recent public hearing, we affirmed our support for the proposed rule as an important and much-needed step toward protecting public health. We also highlighted several opportunities for strengthening the rule even further:

• MassDEP should consider regulating PFAS as a class or as multiple sub-classes based on their chemical similarities to those that are already known to be toxic. There are currently more than 4,700 different PFAS chemicals on the market; approximately 600 PFAS are registered for active use in the U.S. In addition to the six PFAS included in the proposed rule, many other PFAS are frequently detected in drinking water (for instance, PFHxA, PFBS, PFBA, and PFPeA) that are chemically similar to those with known toxicity. It would simply take too long to fully study the toxicity of each PFAS chemical individually. A class-based approach is needed because tackling these chemicals one-by-one or a few at a time would take more than a lifetime.
• Current testing methods used by EPA can only detect around 20 PFAS chemicals and do not include many other types of common PFAS, including ones currently used in firefighting foams—a major source of PFAS contamination in the environment. What’s more, the tests do not look for most so-called precursor compounds—PFAS that have the potential to transform into PFOS, PFOA, and other highly stable compounds—that may also be making their way into our drinking water. Therefore, we encourage MassDEP to consider additional analytical methods in order to fully capture the total amount of PFAS in drinking water and to set a limit based on that, similar to what the European Commission announced in December.
• Our understanding of the many ways that PFAS can affect the human body is rapidly evolving. The more we learn about these contaminants, the more we see health effects at lower levels of exposure. It is critical that MassDEP continue to incorporate new science into its regulations to ensure its drinking water standard is adequately protective. For example, studies show PFOA can alter mammary gland development at very low levels. Changes in breast development could have significant long-term implications for breastfeeding and breast cancer, making this an important health impact to consider. MassDEP should also consider setting individual limits on certain PFAS (in addition to including them in a sum) when there is strong evidence of health effects at low levels of exposure. For instance, under the proposed rule, drinking water with 10 to 20 ppt for PFOA or PFOS would not exceed the Massachusetts standard, but it would exceed standards set by other states.

In short, we applaud MassDEP for being proactive in taking this important step. Drinking water standards should be based on the most up-to-date research and employ the latest analytical methods in order to best protect Massachusetts residents, especially children, from hazardous exposures that could have lasting impacts on their health.