Expert Explains Technology and Investments Needed to Eliminate Chemicals From Drinking Water Forever

Harmful chemicals known as PFAS can be found in everything from children’s clothing to soil to drinking water, and regulating these chemicals has been a goal of public and environmental health researchers for years. On March 14, 2023, the United States Environmental Protection Agency proposed what would be the first set of federal guidelines regulating levels of PFAS in drinking water. The guidelines will be open for public comment for 60 days before being finalized.

Joe Charbonnet is an environmental engineer at Iowa State University who develops techniques to remove contaminants such as PFAS from water. It explains what the proposed guidelines would require, how water utilities could meet those requirements, and how much it would cost to remove these so-called eternal chemicals from drinking water in the United States.

1. What do the new guidelines say?

PFAS are associated with a variety of health issues and have been a focus of environmental and public health researchers. There are thousands of members of this class of chemicals and this proposed regulation would set the allowable limits in drinking water for six of them.

Two of the six chemicals – PFOA and PFOS – are no longer produced in large quantities, but they remain common in the environment because they were widely used and break down extremely slowly. The new guidelines would allow no more than four parts per trillion of PFOA or PFOS in drinking water.

Four other PFAS – GenX, PFBS, PFNA and PFHxS – would also be regulated, but with higher limits. These chemicals commonly replace PFOA and PFOS and are their close chemical cousins. Due to their similarity, they harm human and environmental health in the same way as older PFAS.

A few states have already set their own limits on PFAS levels in drinking water, but these new guidelines, if adopted, would be the first legally enforceable federal limits and would affect the entire United States.

2. How many utilities will need to make changes?

PFAS are harmful even at extremely low levels and the proposed limits reflect this fact. The permissible concentrations would be comparable to a few grains of salt in an Olympic swimming pool. Hundreds of utilities across the United States have PFAS levels above proposed limits in their water supplies and would need to make changes to meet those standards.

While many areas have been tested for PFAS in the past, many systems have not, so health officials don’t know precisely how many water systems would be affected. A recent study used existing data to estimate that about 40% of municipal drinking water supplies could exceed the proposed concentration limits.

3. What can utilities do to meet the guidelines?

There are two major technologies that most utilities are considering to remove PFAS from drinking water: activated carbon or ion exchange systems.

Activated carbon is a charcoal-like substance to which PFAS adhere quite well and can be used to remove PFAS from water. In 2006, the city of Oakdale, Minnesota added an activated carbon treatment step to its water system. Not only did this additional water treatment significantly reduce PFAS levels, but there were significant improvements in birth weight and the number of full-term pregnancies in this community after the change.

Ion exchange systems work by flowing water over charged particles that can remove PFAS. Ion exchange systems are generally even more effective at reducing PFAS concentrations than activated carbon systems, but they are also more expensive.

Another option available to some cities is to simply find alternative, less contaminated water sources. While this is a wonderful and inexpensive way to reduce contamination, it points to a major disparity in environmental justice; more rural, less resourced utilities are unlikely to have this option.

4. Is such a major transition feasible?

By law, the EPA must consider not only human health, but also the feasibility of treatment and potential financial cost when setting maximum levels of contaminants in drinking water. While the proposed limits are certainly feasible for many water utilities, the costs will be high.

The federal government has made available billions of dollars in funding for water treatment. But some estimates put the total cost of complying with the proposed regulations for the entire country at around $400 billion, far more than the funding available. Some municipalities may apply for financial assistance for treatment of nearby polluters, while others may increase water rates to cover costs.

5. What happens next?

The EPA has set a 60-day period for public comment on the proposed regulations, after which it can finalize the guidelines. But many experts expect the EPA to face a number of legal challenges. Time will tell what the final version of the rules will look like.

This regulation is intended to keep the United States in the enviable position of having the highest quality drinking water in the world. As researchers and health officials learn more about new chemical threats, it’s important to ensure that every resident has access to clean, affordable tap water.

While these six PFAS are certainly health threats worth regulating, there are thousands of PFAS that likely have very similar impacts on human health. Rather than playing the chemical mole by regulating one PFAS at a time, there is a growing consensus among researchers and public health officials that PFAS should be regulated as a class of chemicals.

Joe Charbonnet, Assistant Professor of Environmental Engineering, Iowa State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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