By Kevin Westerling,
A conversation with Craig Butt, PhD, and Christopher Higgins, PhD
Per- and polyfluoroalkyl substances (PFASs) are found in many consumer products, as well as in soils and drinking water. These so-called “forever chemicals” earned their nickname thanks to their negligible degradation in the environment. As concerns about PFAS exposures grow, both consumers and regulators alike have begun calling on industry and utilities to reduce or limit PFAS in tap water and commonly used items, such as cosmetics, personal care products, and food packaging.
However, the flurry of proposed new rules, combined with ongoing legal challenges and uncertainties, have left many in the drinking water community confused about what it all means for the industry. To answer some common questions, I sat down with two PFAS experts: Craig Butt, PhD, Manager, Applied Markets, Global Technical Marketing at SCIEX, and Christopher Higgins, PhD, Professor of Civil and Environmental Engineering at the Colorado School of Mines.
To start, what do we know about the potential dangers of PFAS exposures to humans?
CB: Over 5,000 different PFAS chemicals are known to exist, and their impact on humans and the environment varies depending on the specific molecular attributes of each individual compound. While some PFAS chemicals — such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) — have been studied extensively, many others have yet to be formally identified and tested.
What scientists are learning is that PFAS exposures have been linked to negative health outcomes, including immune system problems, elevated cholesterol levels, liver problems, and even cancer. Emerging epidemiological and toxicological studies are showing that there are no safe exposure levels to PFAS for humans, which indicates that even miniscule amounts of contamination can create significant issues.
What are the common ways people are exposed to PFAS?
CB: The first PFAS chemicals were developed in the 1940s. They were — and still are — used in household products with brand names such as Teflon and Scotchgard, as well as in dental floss, shampoo, mascara, and rain gear. Another common source of PFASs in the environment comes from aqueous film-forming foams (known as AFFFs), which are used to extinguish petroleum-based fires.
CH: The ubiquity of PFASs in the modern world makes it difficult to determine precisely how each individual is exposed. What we do know is that PFASs frequently enter the body through the food we eat and the beverages we drink. PFASs are used to keep grease from seeping through pizza boxes and in other packaging, such as microwave popcorn bags. Produce can be contaminated when grown with PFAS-containing water, and we ourselves can be contaminated when we drink that water.
How do PFAS enter our drinking water?
CH: Our work at Colorado School of Mines has shown that, over time, PFASs released into the environment can seep into the soil and move into groundwater or runoff into lakes and rivers. That groundwater or surface water, if inadequately treated, can become a problem if it is used for drinking water. PFASs are also found in sewage sludge (known as biosolids), which is used as fertilizer and spread over agricultural fields. Similar to AFFFs, PFASs in biosolids can leech into groundwater. In addition, these chemicals are found in wastewater, which is treated and recycled. While some wastewater treatment processes reduce PFAS levels, unless they are designed to remove PFAS, the treatment is often insufficient.
How readily each individual PFAS travels through the environment and into groundwater varies depending on the size and chemical properties of each molecule. Generally speaking, the smaller it is, the more rapidly it will move through soil, though it’s not just the size of the molecule that has an effect: there are parts of the molecule (particularly the “head” of the molecule) that can dramatically impact its movement through the soil. This process can take time for some of the bigger molecules, however, so soils will continue to act as PFAS reservoirs in the United States and throughout the world.
How pervasive of a problem are PFAS throughout the United States?
CB: PFASs are detected around the world, not just in the United States. We now appreciate that no corner of the globe is untouched by PFAS contamination. Nearly all humans contain PFASs in their blood. Animals from remote corners of the planet—including those thousands of miles from a manufacturing plant — contain PFASs in their bodies. Scientists have shown that even very low levels of PFAS in the environment — levels measured at parts per billion or parts per trillion — can potentially cause serious health problems. Because PFASs can persist for a very long time in the environment, there is potential for long-term exposure and therefore a lifetime of harmful effects.
How pervasive is PFAS soil contamination, what are the threats, and how can we remediate affected areas?
CH: The levels of PFASs you find in soils depends on where you look. In places where, for example, AFFFs have recently been used, PFAS levels can be quite high. In other places, levels are much lower. Because PFASs don’t readily degrade, even low-level contamination can persist for years.
While remediating affected soils continues to be a challenge, scientists around the world are searching for novel strategies to treat PFAS in impacted waters and soils. These techniques are still being developed and refined, but we are likely going to need a variety of treatment technologies to effectively remediate all the different types of PFAS-impacted sites around the world.
The U.S. EPA has announced a PFAS roadmap as well as draft drinking water guidelines. How will these impact utilities and consumers?
CB: Perhaps the most immediate impact on utilities will be the need for regular, accurate testing of PFAS levels to demonstrate compliance with the new regulations. Improvements in mass spectrometry have allowed scientists to measure ever-lower concentrations of PFASs and other chemicals. This is good for consumers, especially given the low levels of PFASs associated with health problems. It also means that water utilities will need to partner with testing companies that have a long history of PFAS testing and have experience with performing analysis at the parts-per-trillion level, or possibly even the parts-per-quadrillion level. Testing partners also need to know how to test a wide variety of matrices from drinking water to sewage sludge.
What is being done to eliminate PFAS — and the use of similar substances such as GenX — in consumer products? How should manufacturers be held accountable?
CB: Reducing PFASs in consumer products is a balance between pressure from regulators, such as the EPA, and actions voluntarily taken by manufacturers. Consumers can also voice their concerns to regulators and manufacturers, ultimately weighing the benefits of PFASs against their potential toxic effects. Manufacturers can also change the types of PFASs used in their products to reduce the toxicity or biological persistence in the body. If the chosen route is 100% elimination — either from a voluntary or regulatory decision — then accurate PFAS testing will be critical to ensuring that products really are free from PFAS contamination. PFAS will be with us for decades, but we can take steps now to keep the problem from getting worse.