N.C. House and Senate bills could establish contaminant levels for drinking water

Collectively titled the 2023 Safe Drinking Water Act, N.C. Senate Bill 350 and House Bill 610 were filed on March 22 and April 13, respectively. 

If passed, they would mandate that the North Carolina Commission for Public Health must establish maximum contaminant levels (MCLs) for chemicals in drinking water that are probable or known carcinogens or are otherwise toxic.

MCLs are enforceable standards that define the highest concentration of a contaminant allowed in drinking water so there is no known risk to public health. They are determined based on public health risks and cost-benefit analysis. 

Some of the contaminants specifically targeted in the bills are per- and poly-fluoroalkyl substances (PFAS), chromium-6 and 1,4-dioxane. 

PFAS, which include thousands of synthetic chemicals, are a byproduct of commercial and industrial manufacturing and processing. Known as "forever chemicals," they do not break down in water and remain in the environment. They contaminate soil and water, accumulating in fish and wildlife. 

According to the Environmental Protection Agency, PFAS can cause reproductive harm, immune system damage and increased risk of several cancers.

Chromium-6 is considered a carcinogen and can cause allergic dermatitis with extended contact.

While trace amounts of chromium occur naturally in water sources, additional chromium has been released into the environment due to poor industrial waste disposal practices, according to the EPA. 

Dioxane is also a synthetic industrial chemical that has been identified in groundwater sources. The EPA has classified dioxane as a likely human carcinogen. However, there is not much research available to support this point, said Jamie DeWitt, a professor of pharmacology and toxicology at East Carolina University.

The EPA is authorized to set national maximum contaminant levels for public water sources because of the federal Safe Drinking Water Act, which was passed in 1974.

According to the EPA, there are federal MCLs for chromium, and the Biden administration recently announced a proposal to set national drinking water standards for six PFAS.

Grady O’Brien, a policy associate with the North Carolina Conservation Network, said S.B. 350 and H.B. 610 would work well with the federal Safe Drinking Water Act.

“It has the state step in with our Commission for Public Health and establish those maximum contaminant levels for a set of substances that, as of now, there isn't a federal standard for,” he said. “It's kind of working as a supplement and in concert with the federal Safe Drinking Water Act.”

Though there are proposals in the works for federal regulations of several contaminants, N.C. Sen. Graig Meyer (D-Caswell, Orange, Person), a sponsor of S.B. 350, said the bill is meant to anticipate the emergence of new contaminants that would not be federally regulated.

Additionally, H.B. 610 would require that the commission review other states' MCLs that are not already set in federal or North Carolina regulation. The commission would then evaluate whether it is necessary to set additional MCLs for North Carolina.

In addition, the commission would be required to perform an annual analysis of peer-reviewed science to determine whether any additional contaminants should be regulated.

“There's new chemicals being introduced into the world every single day and some of them end up in our water supply. This is a way to try and keep up with what's coming, literally down the pipe,” Meyer said. “None of us want unregulated chemicals in our water.”

DeWitt said North Carolina is leading many states in terms of protecting public health from contaminants in drinking water.

“Our General Assembly and partnership with the Department of Environmental Quality and Department of Health and Human Services is really advancing science to advance protection of public health,” she said. 

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