The City of Burlington released an industrial chemical and probable human carcinogen from one of its wastewater treatment plants eight days ago, it informed Pittsboro on Friday.
Pittsboro’s drinking water intake is located on the Haw River, about 30 miles downstream of Burlington.
The chemical that was released is 1,4-dioxane, a chemical used as an industrial solvent that is difficult for water treatment plants to remove.
Information about how much may have made its way into Pittsboro’s drinking water is not immediately available because labs that test water samples within 24 hours don’t work on weekends. Burlington officials informed Pittsboro about the release Friday afternoon as soon as they learned about it, according to a press release from the town.
“When a release of this type occurs, most of the substance flows downstream together,” Colby Sawyer, a Pittsboro spokesman, wrote in a statement. “The dilution and speed of travel of this bulked substance, or slug, is based on how fast and at what volume the river is flowing.
“We are unsure whether the ‘slug’ has gotten to us yet, is hitting us now, or has already passed us. As a result, we are uncertain of how much, if any, 1,4 dioxane may be in our finished water. We cannot answer these questions until we receive our testing results.”
The town is recommending that people with “sensitive health conditions” avoid drinking the water until it is clear that the chemical isn’t or is no longer impacting the town.
Until tests come back Monday or Tuesday, Pittsboro is drawing as little water as it can from the river, Sawyer wrote. To help with that, Pittsboro is asking residents to cut down on non-essential uses like watering lawns, filling pools or washing cars.
Burlington’s samples from Sept. 14 detected concentrations of more than 1,200 parts per billion of 1,4-dioxane entering one of their wastewater treatment plants and then a concentration of 459 parts per billion leaving the facility.
For reference, a June release of 1,4-dioxane from Burlington involved concentrations as high as 160 parts per billion leaving a wastewater plant. That slug took a week to make its way downstream to Pittsboro’s drinking water intake and then 10 days to clear entirely from its system.
It is not uncommon for routine water tests to take about a week to come back, Sawyer told The News & Observer on Friday. Pittsboro conducts its own routine testing of its intake and drinking water.
“It happens to be that we are about a week downstream. … When they let us know (they have a discharge), we have to immediately start taking action. That’s just the nature of geography and hydrology,” Sawyer said.
The 1,4-dioxane in Burlington comes from industrial customers who have agreements with the City to discharge their wastewater.
The Environmental Protection Agency, which classifies 1,4-dioxane as a likely human carcinogen, has set a health advisory goal of 35 parts per billion in finished drinking water. The N.C. Department of Environmental Quality has set in-stream target values of 0.35 parts per billion in waters that provide drinking water, but an effort to codify that was struck back by the Rules Review Commission last year.
Earlier this year, Burlington reached a settlement with the Haw River Assembly to track which companies sending it wastewater were causing discharges of forever chemicals and require them to either change their processes or cut down on releases. The city pledged at the time that it would undertake a similar effort with 1,4-dioxane.
The regulatory reform bill the General Assembly passed on Friday includes provisions requiring the N.C. Department of Health and Human Services to conduct a health assessment for 1,4-dioxane and the N.C. Policy Collaboratory to evaluate ways to remove the chemical from wastewater that is being discharged.
This story was produced with financial support from the Hartfield Foundation and the 1Earth Fund, in partnership with Journalism Funding Partners, as part of an independent journalism fellowship program. The N&O maintains full editorial control of the work.