By Greg Barnes
The state Department of Environmental Quality said today that it has notified public water utilities downstream of Reidsville that another discharge of the likely carcinogen 1,4 dioxane has again fouled the Cape Fear River basin.
It is the second known release of a large volume of the chemical into the basin since August. This one was detected at the Reidsville wastewater treatment plant, about 20 miles northeast of Greensboro.
According to a statement from the DEQ, an initial sample taken at the treatment plant on Oct. 11 was found to contain 1,4 dioxane at a concentration of 1,400 parts per billion. That’s 40 times higher than the federal lifetime health advisory of 35 parts per billion and 4,000 times higher than North Carolina’s standard for surface waters used for drinking water.
Reidsville’s wastewater treatment plant discharges into the Haw River, which empties into the southern end of Jordan Lake, the headwaters of the Cape Fear River.
Sharon Martin, a spokeswoman for the DEQ, said in an email that the department has notified downstream utilities on the Cape Fear River about the newest discharge. She said the DEQ is analyzing the impacts of the release and how long it would have taken the contamination to reach each water utility downstream. She could not immediately say which utilities had been notified.
Martin said the DEQ hasn’t yet identified a source of the contamination, but her email said Reidsville officials have indicated that two companies participating in the city’s industrial pretreatment program — DyStar and Unifi Inc. — are possible sources. Under the program, major industries are required to have waste discharge permits that are issued by cities.
N.C. Health News first identified those companies as possible sources of 1,4 dioxane in a story in September 2016. According to that story, Unifi is a Greensboro-based manufacturer of polyester and nylon yarns, while DyStar, owned by Kiri Holding Singapore, produces dyes and other chemicals. Representatives of those companies could not be reached for comment Tuesday night.
Earlier this month, N.C. Health News reported that Greensboro-based Shamrock Environmental Corp. was responsible for a release of 1,4 dioxane found in Pittsboro’s drinking water at a concentration of 107 parts per billion on Aug. 23.
That concentration is three times higher than the U.S. Environmental Protection Agency’s lifetime health goal of 35 parts per billion. According to the EPA, a person who drinks that level over a lifetime stands a 1 in 10,000 chance of getting cancer. Pittsboro is the only municipality to draw its drinking water from the Haw River.
Greensboro officials learned about the contamination in mid-August but did not notify the state until Sept. 27, after DEQ officials said the 1,4 dioxane had dissipated in drinking water downstream. The initial sample, taken Aug. 7, measured the contaminant at 957 parts per billion, significantly less than the 1,400 parts per billion measured in Reidsville.
Wilmington and Fayetteville recorded elevated levels of the contaminant in September, more than a month after the release happened. A Fayetteville official said the DEQ never notified him of that discharge. He could not be reached for comment Tuesday evening.
Utilities cannot screen out 1,4 dioxane using conventional filtering systems.
Shamrock, which handles and treats waste for other industries, said another company failed to tell it that its wastewater contained 1,4 dioxane. Shamrock did not identify the other company.
Greensboro officials said they handled notification of the contamination according to state protocol. The state is considering taking enforcement action against Greensboro over the notification issue and because the city holds the pretreatment program permit for Shamrock.
Martin said the release in Reidsville was discovered as part of the DEQ’s recent investigation into industries polluting the Cape Fear River basin.
In July, the DEQ required 25 municipalities in the Cape Fear River basin with pretreatment programs to begin sampling for 1,4 dioxane and perfluorinated compounds, commonly known as PFAS or “forever chemicals’’ because they don’t break down easily.
The DEQ hopes the sampling, which ended Sept. 30, will give cities a better understanding of who is releasing the contamination so it can be stopped.
Greensboro has been required to take weekly samples since shortly after the state learned about Shamrock’s release of 1,4 dioxane. In its statement, the DEQ said results of the latest samples, which were received Tuesday, show a concentration of 20 parts per billion of the contaminant on Oct. 7 and 45 parts per billion on Oct. 11. Results from both samples far exceed the state standards for surface water of 0.35 parts per billion.
The DEQ is also now requiring Reidsville’s wastewater treatment plant to take weekly samples as part of its investigation into the latest discharge.
Industries use 1,4 dioxane primarily as a solvent or solvent stabilizer. It can be found in paint strippers and varnish and as a byproduct in detergents, shampoos, cosmetics and other household products.
Animals exposed to large concentrations of 1,4 dioxane in laboratory studies have suffered liver and kidney damage, as well as cancer.
Correction: This article originally stated that the Reidsville wastewater treatment plan discharges into Troublesome Creek. It actually discharges directly into the Haw River.