Researchers from Duke and N.C. State this week briefed Pittsboro officials on the presence of unregulated chemicals in the town's water supply.
They are investigating how 1,4-Dioxane, a likely carcinogen, and several different types of PFAS are entering the Haw River, which is the water source for the town.
1,4-Dioxane is a synthetic chemical used in manufacturing. Per- and polyfluoroalkyl substances, or PFAS, are a group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals.
Heather Stapleton, an associate professor at Duke's Nicholas School of the Environment, said a wastewater treatment plant in Burlington is likely one source of PFAS contamination.
“From our analysis, it suggests that there is an input from the wastewater treatment plant for these specific types of perfluorinated carboxylic acids that are more prevalent in the Pittsboro water supply,” she said.
Stapelton’s research is focused on PFAS, while N.C. State professor Detlef Knappe is studying the presence of 1,4-Dioxane. Both say the levels of these contaminants in the Haw River fluctuate throughout the year.
In mid-August, 1,4-Dioxane levels in the Haw spiked from an average level of 1-10 micrograms per liter to more than 100 micrograms per liter, Knappe told Pittsboro commissioners, possibly due to a discharge from an unknown storage tank.
“We don’t know exactly where it’s coming from, but these levels are unbelievably high,” said Knappe. “Your water plant is not equipped to handle this, actually almost no water plant in the whole country would be able to handle this.”
He told the board the E.P.A. recommends an upper limit for drinking water of 35 micrograms per liter, but noted it is only a guideline, not an enforceable standard. Knappe said more needs to be done to identify where the chemical is coming from and keep it out of the drinking supply.
Pittsboro sent a letter to water customers last month alerting them to the presence of 1,4-Dioxane, bromides, PFOS, and PFOA.
The letter states that the Pittsboro Water Treatment Plant meets all state requirements for safe drinking water.
“The State of North Carolina and the Federal Government have not set limits on how much of these compounds are safe when present in drinking water,” it notes. “The health effects of these emerging contaminates are not fully known, however studies of these compounds are being conducted nationwide. The Town is pursuing near-term and long-term plans to address these emerging contaminates.”
Stapleton said residents who are concerned about contamination should consider filtering their drinking water at home.
“Any type of filter would help remove at least some of it,” she said. “Some filters don’t remove all of it, but they will remove some of it.”
Town officials are in the process of exploring options for expanding the capacity of the water treatment plant and adding advanced filtration equipment. In the meantime, Stapleton is planning to study how exposure to PFAS affects residents in Pittsboro.