Cape Fear: 1,4-Dioxane Imperils N.C. Drinking Water

Increased treatment processes apparently haven’t been enough to curb levels of a potentially dangerous contaminant in a North Carolina water supply.

Raw water tests of the Cape Fear River last month showed that levels of 1,4-dioxane — an industrial solvent used in paint strippers, soaps, antifreeze, and other products — in the supply are increasing. The contaminant has been known to cause kidney and liver damage when consumed through drinking water. While treatment has helped, the issue seems to persist even in finished water.

Test results made public recently showed that raw water contained 1,4-dioxane at 1.8 parts per billion (ppb) and that finished water that was already treated at nearby Sweeney Water Treatment Plant contained 1,4-dioxane at 0.54 ppb. The U.S. EPA has not set a maximum contaminant level for the compound in drinking water, but has said that consuming water with more than 0.35 ppb of 1,4-dioxane could increase the risk of cancer.

This level of 1,4-dioxane treatment, which did not get the compound reduced to completely safe levels, was only possible because the local treatment plant is specially equipped.

“A number of investments at Sweeney Water Treatment Plant, which treats water drawn from the Cape Fear River, make CFPUA [the Cape Fear Public Utility Authority] one of the few water utilities in North Carolina equipped to significantly reduce 1,4-dioxane in water,” per a news release from the utility, reported by WECT. “Those technologies, ozone and granular activated carbon filters operated in biological mode, typically result in removal rates of 67 percent or better.”

At the time of this writing, it was not clear how CPFUA plans to get 1,4-dioxane levels in the area down. Officials from the utility are reportedly “in discussions with the North Carolina Department of Environmental Quality about the recent 1,4-dioxane spike” and will continue to monitor levels, per WECT.

It’s possible that, beyond improved treatment processes from the utility, the industrial operations along the water supply may need to evolve.

“There are several industrial dischargers of the compound in the river basin,” The Progressive Pulse reported. “Along the Cape River itself, DAK Americas in Fayetteville, which manufactures plastic resins, such as PET, has also been known to discharge 1,4 dioxane into the Cape Fear. According to the facility’s discharge permit, it conducts annual monitoring for 1,4 dioxane at one of its outfalls that funnels stormwater and wastewater into the river.”

To read more about how drinking water utilities deal with contaminant spikes, visit Water Online’s Drinking Water Contaminant Removal Solutions Center.