2.3 million North Carolinians rely on wells for their drinking water, but some 20 percent of the wells surveyed in the study had manganese levels that exceeded the EPA's recommended limit. Image courtesy of Wikimedia Commons.

By Catherine Clabby

Which standards should state government use to alert people that their drinking water is unsafe? In the wake of increased scrutiny to coal ash ponds, this question has gone from affecting some North Carolinians to affecting us all.

Last year, state health officials sent do-not-drink advisories to owners of 360 water wells located near 14 Duke Energy properties storing coal ash waste. That came after tests detected contaminants linked to coal ash in the water, particularly vanadium and hexavalent chromium.

This year, state officials withdrew most of the alerts (see letter at bottom of page). Tests of wells not close to coal ash dumps had comparable levels of both elements, suggesting possible natural sources of contamination of the wells, they said. State health-screening levels that triggered the warnings, they stressed, were stricter than most state or the federal limits.

Based on data like these, state legislators are mulling which standards to use when judging health risks from many more contaminants found in well water and in public water supplies.

When DEQ posted well test results last August as part of its coal ash risk assessment, the agency listed three standards then current based on state groundwater rules, on federal maximum contaminant levels (MCLs), and on DHHS health screenings. Variations among the levels is visible here. Levels are noted in parts per billion (ppb), parts per million (ppm) or no standard. Asterisks denote EPA’s non-mandatory “secondary” federal MCLs.

Maximum contamination limits

Two bills introduced with that goal would also forbid local, county and state health officials from issuing health advisories that don’t conform to the standards lawmakers select, a prospect prompting some opponents to accuse legislators of crafting, intentionally or not, a gag rule.

“We’ve got plenty of contaminants for which there is no standard. Or there is a standard but it lags years behind the science in terms of telling us what is safe. It’s very important that if state or local government officials know it’s unsafe, that they be able to tell,” said Grady McCallie, policy director for the N.C. Conservation Network.

The state’s Department of Environmental Quality and Department of Health and Human Services favor water health-risk evaluation standards based upon federal maximum contamination limits, or MCLs, created under the federal Safe Drinking Water Act, said Crystal Feldman, DEQ’s deputy secretary for public affairs.

The federal government defines MCLs as the highest levels of contaminants allowed in drinking water, and they are close to EPA health benchmarks, but also considers clean-up costs, public health benefits and the feasibility of detecting and removing the contaminants.

Comparisons of N.C. groundwater, federal maximum contamination limits and DHHS warning levels. Levels are noted in parts per billion, parts per million or no standard. Asterisks denote EPA’s non-mandatory “secondary” federal MCLs.

Whose standards?

Bills filed in the House and Senate by two of the three chairmen of the legislative Environmental Review Commission so far propose using the federal MCLs and limits linked to state groundwater standards. Those state standards, often stricter than the federal MCLs, are used to determine contaminant levels allowed after clean up of detected groundwater pollution.

Groundwater supplies water to wells, which about half of North Carolinians depend upon for their drinking water.

Rep. Jimmy Dixon (R-Warsaw) said sponsors, himself and Sen. Trudy Wade (R-Jamestown) included, intentionally submitted bills with preliminary language. They wanted to get an important topic – how to prevent a do-not-drink advisory from being issued and then withdrawn – resolved during the current legislative session, he said.

Deborah Graham (left) of Dukeville and Amy Brown of Belmont received “do-not-drink” letters last year, only to receive subsequent letters saying they could drink their well water. The two attended Duke Energy’s stockholders’ meeting this week. Photo courtesy Amy Brown.

“We don’t want to issue directions for no drinking and then take it back. Once you ring the bell, it’s hard to un-ring it,” Dixon said. “I want us to learn from those experiences and craft better language and legislation so that we face these situations differently in the future.”

People who received advisories that were later rescinded have expressed anger and suspicions in multiple public meetings. Among them are Amy Brown of Belmont and Deborah Graham of Dukeville, who live within 1,000 feet of different coal-waste impoundments.

Legislators should retain the strictest standards state health officials have created to assess risks in residents’ drinking water, the women said.

“I don’t understand why the state is working so hard to limit information. Everyone should know what they need to know about their water and be advised about it,” said Brown, who, with Graham, attended a Duke Energy stockholders meeting Thursday and met with company officials to explain their concerns about their water.

Comparisons of N.C. groundwater, federal maximum contamination limits and DHHS warning levels. Levels are noted in parts per billion, parts per million or no standard. Asterisks denote EPA’s non-mandatory “secondary” federal MCLs.

No cleanup needed?

North Carolina’s health-screening levels for private drinking-water wells, as they are called, are not regulations that require polluters to clean anything up. DHHS health officials create them when a test is requested for a constituent that is not part of routine well analysis, said Alex Lefebvre, a DHHS press assistant. Calculations used are purely health based and correspond to an incremental lifetime cancer risk of one in a million.

Coal ash clean up-related well test results released by DEQ in August list multiple DHHS screening levels stricter than federal levels for contaminants with well-documented toxicities, including barium, boron, cadmium, mercury, selenium, thallium and zinc.

California and North Carolina share the lowest groundwater standard for hexavalent chromium in the country at 10 ppb. Only eight states in the U.S. have groundwater standards for vanadium, and the federal government does not require city water supplies to monitor for vanadium.

DEQ officials have been particularly critical of the fact that the DHHS health-screening levels for hexavalent chromium, when shared with well owners last year, were not put in context with less strict federal contaminant standards. Among the 424 water wells near coal ash sites issued do-not-drink advisory letters, 12 wells exceeded the federal standards alone, DEQ has reported. Of those, seven had too-high levels of lead and five for arsenic.

Comparisons of N.C. groundwater, federal maximum contamination limits and DHHS warning levels. Levels are noted in parts per billion, parts per million or no standard. Asterisks denote EPA’s non-mandatory “secondary” federal MCLs.

In a report last month submitted to the ERC, DEQ said health officials should put strict contamination levels in a wider context: “DEQ recommends that DHHS include additional clarifying information … that explains that both bottled water, regulated by the US Food and Drug Administration (FDA) and water supplied by a public water supply regulated by the US EPA may potentially, and legally, contain up to 100 ug/L of hexavalent chromium, measured as total chromium.”

Ken Rudo, a toxicologist with the state Division of Public Health, has defended the state screening levels for water contaminants publicly. In a video of a public meeting on well water contaminants in Salisbury and posted online by the environmental group Appalachian Voices, Rudo said, “It’s a low risk, but it’s higher than what we in public health consider to be safe. Sometimes that view might be different than others’.”

Efforts to ask Rudo, who is taking time off from his state position, about the health-risk advisory bills have been unsuccessful.

Feldman, the deputy secretary, said DEQ support for using one health-advisory standard for all drinking water is consistent with an Association of State and Territorial Health Officials call for consistent standards for small and large water systems. The organization does not endorse one set of standards, however.

“ASTHO also supports the right of states to establish more stringent MCLs if they deem appropriate or establish MCLs for federally unregulated substances,” spokesman Scott Briscoe said.

Comparisons of N.C. groundwater, federal maximum contamination limits and DHHS warning levels. Levels are noted in parts per billion, parts per million or no standard. Asterisks denote EPA’s non-mandatory “secondary” federal MCLs.

Groundwater is contaminated beneath all 14 Duke Energy sites holding coal waste, DEQ has said, and the agency is finishing evaluations of risks to nearby drinking wells and public drinking supplies. Duke Energy continues to provide bottled water to nearly 400 homes.

Along with well owners and environmentalists, the company is following how state officials characterize contaminants in water sources near its coal ash waste.

In its latest Securities Exchange Commission annual report filing, the company noted that lawsuits regarding drinking wells could occur. “It is not possible to estimate the maximum exposure of loss, if any, that may occur in connection with claims which might be made by these residents,” the entry read.

DHHS-WellWaterDrinkOKletter (PDF)

DHHS-WellWaterDrinkOKletter (Text)

Republish our articles for free, online or in print, under a Creative Commons license.

Catherine Clabby

Catherine Clabby (senior environmental reporter) is a writer and editor. A former senior editor at American Scientist magazine, Clabby won multiple awards reporting on science, medicine and higher education...

3 replies on “For Drinking Water Warnings, Lawmakers Debate Which Standard To Use”

  1. I am one of these families fighting for the RIGHT to know what is in my drinking water. The background wells in my area around Buck are NO WHERE NEAR THE LEVELS WE HAVE CLOSER TO THE ASH ITSELF. All 14 Duke sites across our state has contaminated groundwater and that groundwater is shared with families living near them. State is run by McCrory who protects Duke and hand-appointed the people that made these decisions about our water. Duke paid a lot of money to get McCrory in that seat and he sure has protected them. Distrust against Duke and our state continues to ve with us each day.

Comments are closed.