PITTSBORO — Analysis of Pittsboro water samples released Wednesday morning suggests the town’s drinking water is probably safe for consumption, despite substantial upstream contamination last week, according to Town Manager Chris Kennedy.
Last Thursday, the City of Greensboro and the North Carolina Dept. of Environmental Quality reported a discharge of 1,4-Dioxane into South Buffalo Creek — a Haw River tributary — in effluent from Greensboro’s TZ Osborne Wastewater Treatment Plant. The chemical is a suspected carcinogen derived from industrial runoff.
Preliminary samples in Greensboro indicated levels between 543 parts per billion and 687 parts per billion of 1,4-Dioxane were discharged. The U.S. Environmental Protection Agency recommends no more than 35 ppb in healthy drinking water.
After learning of the pollution last Thursday, Pittsboro staff began testing the town’s water supply, Pittsboro Water Plant Superintendent Adam Pickett told the News + Record, and took daily samples over the following five days. Results, which were processed at Reidsville’s Meritech Labs, came back Wednesday.
“We remain confident that our water is safe for consumption and use in both residential and commercial applications,” Kennedy said in his Wednesday press release announcing the results.
In the immediate wake of Greensboro’s contamination, 1,4-Dioxane levels at Pittsboro’s raw water intake were non-detect. Two days later a raw water sample included 76.5 ppb, and later samples showed 38.2 ppb and 43.7 ppb over the next few days — all in excess of the EPA’s guidelines.
Finished water at several of Pittsboro’s water tanks, however, contained much lower concentrations of 1,4-Dioxane. The highest level was 5.56 ppb on Tuesday.
“While we are encouraged by these numbers,” Kennedy said in the release, “town staff continues to sample and will do so until we see levels in a non-detect state for an extended period.”
Another round of test results are expected before the end of the week.
“Town staff is confident that these levels will continue to diminish to a level of non-detect in the coming days,” Kennedy said.
So far, the of original source of 1,4-Dioxane contamination remains unknown. Greensboro is obligated to limit 1,4-Dioxane discharge per a Special Order of Consent between the city and NCDEQ signed in February. The SOC stipulates no more than 45 parts per billion of 1,4-Dioxane may be discharged per day. The agreement was triggered in 2019 after the discovery that Shamrock Environmental — an environmental and industrial waste management services company — was dumping 705 parts per billion to 1,210 parts per billion of 1,4-Dioxane at the TZ Osborne plant. The Shamrock location in Greensboro is a tanker cleaning facility that also manages wastewater and recycles drilling mud.
As of Wednesday afternoon, a notice on Greensboro’s website said the city was still unsure where the most recent contamination originated.
“City staff has notified and is in coordination with the N.C. Department of Environmental Quality (NCDEQ) and downstream utilities and is actively investigating possible sources of the substance,” it reads.
The notice points out “this discharge does not affect Greensboro’s drinking water quality.”
“So that’s what Greensboro is working on,” Pickett said, “trying to figure out where this source is coming from all of a sudden. And we’re working with Greensboro, as well, so hopefully we can get this knocked down pretty quick.”
This is a developing story. Check back on chathamnewsrecord.com for updates.
Reporter D. Lars Dolder can be reached at email@example.com and on Twitter @dldolder.
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