1,4 Dioxane detected in Haw River, drinking water within safe limits


PITTSBORO — Alerts were issued over the weekend related to a chemical found in the Haw River, but preliminary testing of Pittsboro's drinking water does not show dangerous levels of the compound. Routine sampling in Alamance County detected the presence of the chemical 1,4-dioxane in the Haw River last week, prompting testing of drinking water supplies downstream of Burlington. 

On Friday, the City of Burlington's wastewater treatment plant detected the presence of dioxane in the effluent discharged into the Haw River, which had passed through Burlington’s plant, raising questions about the safety of Pittsboro's water supply. 

Samples collected in Burlington on Thursday, September 14, showed dioxane concentrations exceeding 1200 parts per billion entering the plant, significantly higher than recommended safety levels. After treatment, the water leaving the plant contained 459 ppb of dioxane. 

After being alerted, the Pittsboro's water plant staff sought ways to expedite further testing. Due to the unavailability of testing facilities over the weekend, rush samples were delayed until this week. Tuesday morning, the town released the initial results, which showed the concentration of dioxane in the town’s water was “significantly lower than the U.S. Environmental Protection Agency’s Health Advisory level.”  

The town tested at six sites along the Haw River, and none exceeded 6.77 ppb. The level which would prompt a health advisory is 35 ppb.  

A release from the town on Tuesday morning said, “The Town is cautiously optimistic with these results, which indicate whether the ‘slug,’ or concentrated area of 1,4 dioxane, has passed us and we had minimal uptake, or it is just now reaching us. Our test results from composite samples taken over the weekend are expected tomorrow, as are our rush samples taken from the locations listed above. Once we receive these results, we can determine if our 1,4 dioxane concentration is moving in a positive or negative direction.” 

Pittsboro has taken precautionary measures, including operating the water plant 24 hours a day and drawing only the minimum required water to maintain the water system. The town also encouraged residents to voluntarily conserve water by minimizing non-essential uses such as landscape irrigation, vehicle and house washing, and pool filling. The town also made clear the measures are purely precautionary and there is no immediate threat to the town's water supply. 

While Pittsboro addresses immediate challenges, the City of Burlington is actively investigating the source of this pollutant. The issue traces back to August when elevated levels of 1,4-dioxane were detected during sampling at Pittsboro. The N.C. Department of Environmental Quality (NCDEQ) then contacted the Burlington and Reidsville Water Resources Departments, as routine wastewater sampling in Greensboro did not indicate elevated 1,4-dioxane levels. 

Burlington Water Resources conducted thorough investigations, identifying discharges into the South Burlington Wastewater Treatment Plant as the probable source. Staff systematically sampled sewer outfalls and regulated significant industrial users. Their previous experience in identifying PFAS sources proved valuable in this situation, given the elusive nature of such discharges. 

Burlington is collaborating with regulatory agencies, downstream water providers, and potentially responsible industries to address this contamination issue promptly and ensure compliance with state and federal regulations. 

Burlington had already agreed in August to require new or expanding commercial users to provide information about the use of dioxane and to perform additional testing on its wastewater.