Discharge from the Reidsville wastewater treatment plant recently contained extremely high levels of 1,4-Dioxane, a likely human carcinogen, according to state environmental officials.
As part of its investigation into 1,4-Dioxane levels in the Cape Fear River Basin, including the Haw River, DEQ sampled effluent from the Reidsville plant; results from Oct. 11 showed it contained 1,400 parts per billion.
The EPA does not regulate 1,4-Dioxane, but has set a health advisory goal of 0.35 ppb for surface water. That is based on a 1 in 1 million cancer risk.
(Updated 2018 recommendations from the EPA have confused the issue. Those list the levels at 35 ppb for drinking water, but at a less stringent, 1-in-10,000 cancer risk.
Policy Watch is using the more protective 0.35 ppb number for drinking water that N.C. State scientist and 1,4-Dioxane expert cites in his public presentations.)
Using that figure as a benchmark, Reidsville’s discharge was 4,000 times greater than the health advisory goal.
In an announcement released yesterday evening, DEQ said Reidsville officials have identified DyStar and UniFi as possible sources of the chemical. DyStar is a global company specializing in dyes, colorants, and chemicals for textiles, including clothing, as well as food packaging and personal care products. UniFi is a fiber company with factories worldwide.
Earlier this month, DEQ announced that high levels of 1,4-Dioxane had been detected in Greensboro’s wastewater discharge .
That resulted in what NC State scientist Detlef Knappe called “very alarming” levels of the compound — 114 ppb — in Pittsboro’s drinking water downstream. Knappe told attendees at a public forum last week that people who are on Pittsboro’s water system were likely exposed to these levels for about a week. Pittsboro draws its water from the Haw River.
Greensboro officials attributed its spike in 1,4-Dioxane to Shamrock Environmental, which discharged 15,000 gallons of contaminated wastewater into Greensboro’s system. Shamrock Environmental received the material from one of its customers, but declined to name the client to either Policy Watch or the City of Greensboro.
Levels in Greensboro have decreased to 20 ppb on Oct. 7, but rebounded to 45 ppb on Oct. 11, the same day Reidsville’s spike occurred.