PITTSBORO — The latest testing results following a release of 1,4 dioxane in the Pittsboro drinking water system, indicates the situation is continuing to improve.
Test results in which samples were taken on Friday, July 28 were as follows:
The continued decrease in the concentration of 1,4-Dioxane in the raw, finished, and tank water samples indicates that the slug, or concentrated area, of 1,4 dioxane in the Haw River has either already passed or is in the process of passing through the town and has become increasingly heavily diluted.
Additional samples were taken over the weekend and on Monday, July 31 to verify the downward trend in concentrations. Those results are expected by Thursday afternoon.
The town is also flushing the water distribution system over the next week.
Defined as an emerging compounds along with PFAS, studies have been conducted over the past five years to determine the presence of these compounds in various water supply reservoirs across the state. Local, state and federal efforts have been underway to develop an overall management strategy to reduce the compounds’ levels within water supplies.
Since November 2017, the North Carolina Division of Water Resources (NC DWR) has collected 1,4-Dioxane samples at 148 surface water locations throughout 12 of the 17 river basins in NC. Most sampling has occurred in the Cape Fear, Neuse, and Yadkin-Pee Dee River basins.
On Monday, July 24, routine testing results first indicated the presence of 1,4-dioxane. At this time, the amount of 1,4-dioxane in the finished water was 11.9 µg/l, well below the EPA Health Advisory Level (HAL) of 35 µg/l. The test results for raw water entering the plant did not detect the presence of 1,4-dioxane, so additional testing was performed to determine if the town had gotten incorrect results.
Out of an abundance of caution and to investigate whether any upstream utilities had any 1,4-dioxane discharges, Town staff immediately contacted the City of Greensboro, who provided test results showing that there had been no discharge from their wastewater treatment plant.
Staff from Pittsboro, Greensboro, and the N.C. Department of Environmental Quality (NCDEQ) then contacted the City of Burlington, which sent samples taken last week from two wastewater treatment plants to a testing lab on Tuesday, July 25.
On Wednesday, July 26, Pittsboro and Burlington received their results: based on all available evidence, a significant quantity of 1,4 dioxane had been released into the Burlington wastewater treatment system and discharged into the Haw River before routine testing would have indicated its presence.
The City of Burlington's results at the South Burlington Wastewater Treatment Plant (WWTP) were:
The Town of Pittsboro's results (samples taken on Monday, July 24) were:
Pittsboro officials said when a release of this type occurs, most of the substance flows downstream together.
Test samples taken in Pittsboro on Wednesday, July 26, indicate that the concentration of 1,4-dioxane in the Town's finished water is down to 3.57 µg/l. The nature of these events, coupled with the decreasing concentrations seen in Pittsboro's water, indicate that the "slug" of 1,4-dioxane has likely already passed the Town's water intake, meaning that concentrations will continue to decrease.
“Although this release event was significantly less impactful than previous releases, we understand that this news may cause some anxiety or concern,” town officials posted on the Pittsboro government website.
"As we move forward, the utility merger with the City of Sanford is essential for the health and future of the town, as the merger will allow the regional system to use multiple independent sources of water for treatment and distribution,” a statement read.
Additional updates will be provided by Pittsboro officials until a non-detectable level of 1,4-dioxane is reached.