CFPUA confirms 1,4-dioxane found in raw water for fourth time this year

Updated: Sep. 25, 2019 at 4:52 PM EDT
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NEW HANOVER COUNTY, N.C. (WECT) - The Cape Fear Public Utility Authority (CFPUA) has asked for assistance from the North Carolina Department of Environmental Quality after a fourth increase in 1,4-dioxane levels this year.

CFPUA has asked for guidance after detecting elevated levels of the synthetic chemical in raw water from the Cape Fear River.

“We have seen an elevated level of 1,4-dioxane here in our last sample in September and this is the fourth time this year. Sometimes it comes back down and then comes back up and each time we get these elevated results, we have contacted the state for guidance because at the end of the day, the state is regulating the agencies upstream and we are also interested in where it’s coming from and what is being done about it to control the levels in the river,” said Carel Vandermeyden, CFPUA Deputy Executive Director.

CFPUA periodically tests raw water for 1,4-dioxane, which is used in industrial solvents and for several years has been detected in the Cape Fear River and other North Carolina surface waters.

The latest test results showed concentrations of 1,4-dioxane at 6.3 parts per billion (ppb) in raw (untreated) water on September 9 and 1.3 ppb in finished (treated) water at the Sweeney Water Treatment Plant on September 10.

The most recently detected levels are far higher than the levels of 1,4-dioxane detected in the water on three different occasions earlier this year.

In July, 2.2 ppb was found in raw water. In June, 1.5 ppb was detected in raw water. And in February, 1.8 ppb was detected in raw water.

These results and others are posted on CFPUA’s website.

The Sweeney Plant, which treats water from the Cape Fear, was able to significantly reduce 1,4-dioxane in the water through its filters.

“Our Sweeney plant is actually one of the very few plants that has advanced technology that removes 1,4-dioxane at least two-thirds of it. We typically get around 67-70 percent removal through our treatment plant and this last sample in September we actually reached about 80 percent removal. But again, our philosophy is that it should not be in the water in the first place. We have a great treatment plant that can remove a good portion of it, but it would be better if it wasn’t in the water in the first place,” Vandermeyden said.

No federal maximum contaminant level has been established for 1,4-dioxane.

“The EPA is responsible for setting maximum contaminant levels for these type of compounds and drinking water and they have a process called the unregulated contaminate monitoring rule and that is sampling every five years for different chemicals. 1,4-dioxane has been sampled for that but those results have not gone all the way through the regulatory process to come up with a maximum contaminant level if that will ever happen,” he said.

A risk assessment by the U.S. Environmental Protection Agency has indicated that a concentration of 0.35 ppb in drinking water consumed daily over a lifetime would be expected to cause no more than one additional case of cancer in 1 million people.

CFPUA’s monitoring has usually shown 1,4-dioxane concentrations below this level in finished drinking water.

A number of factors may affect concentrations of 1,4-dioxane in the Cape Fear, including river flows. Regardless, the most effective way to address the issue remains controlling discharges at their sources.

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