Articles in a local newspaper in New Jersey and North Carolina demonstrate a national “pandemic” – stories describing widespread PFAS contamination in drinking water across their respective states. According to the articles, PFAS has been linked to cancer and a host of other health problems, resulting in great danger to public health.
I will focus on PFAS found in drinking water, using New Jersey as an example, and a lawsuit filed in June, focusing on the approach EPA used to develop the drinking water regulation for PFAS.
The Dose Makes the Poison
Nearly 500 years ago, Swiss physician and chemist Paracelsus expressed the basic principle of toxicology: “All things are poison, and nothing is without poison; only the dose makes a thing, not a poison.” This means a substance can cause harm only if it occurs in a high enough concentration, and any chemical, including water and oxygen, can be toxic if too much is taken into the body.
It is essential to distinguish between low levels of PFAS in drinking water and high concentrations in industrial releases and contamination from military sites. In cases of high concentrations, clean-up is appropriate and necessary.
However, the EPA appears to have forgotten Paracelsus’s principle in its regulation of PFAS. It has set the Maximum Contaminant Level (MCL) for PFAS, the legally enforceable drinking water standard, so low that any amount found in the environment is considered harmful. In the news article about New Jersey water, the PFAS levels found in drinking water were compared to the MCL and deemed unsafe.
How Did We Get Here?
- In 2016, the EPA set health advisories (safe levels) for PFOA and PFOS (the two most studied PFAS) of 0.070 parts per billion (ppb).
- In 2022, the EPA lowered the values of those health advisories using flawed risk assessments, which misrepresented the scientific data.
- In 2023, the EPA, using a Maximum Contaminant Level Goal (MCLG) of zero for both compounds because they considered them “likely carcinogens,” proposed an MCL of 0.004 ppb for PFOA and PFOS. There is no clear evidence that they cause cancer.
- In April 2024, the EPA finalized the MCL of 0.004 ppb, even though it is below the level many laboratories can detect. It will cost water supplies billions of dollars to remove PFAS to this level.
“The EWG can't tell a toxic chemical from a badminton shuttlecock.”
- Dr. Josh Bloom
Both news articles provide links to a map from the Environmental Working Group (EWG) as the source for their PFAS data. However, it is always far better to consider the original source. The data, uninterpreted by the EWG, can be found on EPA’s website: Fifth Unregulated Contaminant Monitoring Rule Data Finder | US EPA, which contains the analytical results from EPA’s Fifth Unregulated Contaminant Monitoring Rule. This rule requires all large and some small water systems to sample their water systems for 29 individual PFAS chemicals between 2023 and 2025. The website contains the data received as of April 11, 2024, representing approximately 35% of the expected results.
Searching the data from New Jersey for PFOA and PFOS revealed:
- 44% of the water systems tested had an average PFOA concentration of 0.009 ppb (above the MCL of 0.004 ppb).
- 24% of the water systems tested had an average PFOS concentration of 0.007 ppb (above the MCL of 0.004 ppb).
It is hard to visualize how small these levels are. Here are two ways to think about it: One ppb is equivalent to one drop of impurity in 500 barrels of water, or one ppb is 1 cent out of $10 million. A level of 0.007 ppb (the average level of PFOS) is seven-thousandths of one ppb.
These levels are so low that they present no public health risk. Even the highest levels detected (0.03 ppb PFOA and 0.023 ppb PFOS) are below safe levels.
What are safe levels for PFAS?
The MCLs would be considered safe levels for most chemicals. However, this is not the case for PFAS because the EPA jury-rigged the process by 1) designating them as carcinogens and 2) setting the MCLGs (health goals) at zero. This allowed EPA to set the MCLs at 0.004 ppb, based on the lowest “technical feasibility” detectable measures. [1]
An independent group, The Alliance for Risk Assessment, took a fresh look at safe levels for PFAS. In 2022, they recruited 24 scientists from eight countries to review relevant information and independently develop ranges for PFOA and PFOS safe levels. They completed their risk assessment for PFOA in 2023; a PFOS assessment will be completed shortly, estimating that PFOA doses of 0.01–0.07 micrograms per kilogram body weight per day protect human health. Converted to drinking water [2], this corresponds to approximately 0.07 ppb – 0.40 ppb.
Using 0.07 ppb as a safe level, both the maximum level of PFOA detected, 0.03 ppb, and the average, 0.009 ppb, in New Jersey water supplies are below the safe level, indicating no threat to public health.
Recent action by the American Water Works Association (AWWA) and the Association of Metropolitan Water Agencies (AMWA) may provide a chance to redo the PFAS regulation. On June 7, they petitioned the US Court of Appeals for the District of Columbia Circuit to review the final PFAS rule, arguing that the EPA did not rely on the best available science and underestimated nationwide costs.
The EWG, among other groups, is generating enormous distrust based on scientifically flawed risk assessments. From a practical perspective, if the litigation does not result in changes to the PFAS rule, in addition to unnecessary fear, consumers across the US will see higher water bills with no health benefits.
[1] For chemicals without MCLs, the higher Health Advisories levels are considered safe levels, but this is not applicable for PFAS because the EPA set the Health Advisories using flawed risk assessment.
[2] Conversion assumes a 70 kg adult drinking 2 liters of water daily and a 20% contribution from drinking water.
