The order followed a closed session to discuss a dispute over consent between the DEQ and Greensboro.
By Greg Barnes
The North Carolina Environmental Management Commission wants further investigation into a significant release of the likely carcinogen 1,4 dioxane that was detected on June 30 at a wastewater treatment plant in Greensboro.
The commission voted Tuesday to ask the Water Resources Division of the Department of Environmental Quality to investigate the release, which resulted in high levels of the contaminant reaching Pittsboro’s drinking water supply downstream.
The Water Resources Division was tasked with reporting its findings and recommendations to the commission.
The decision follows a closed-door meeting in which the committee announced it would discuss a petition filed on behalf of the Haw River Assembly and the town of Fayetteville seeking to overturn a special consent order the DEQ made with Greensboro earlier this year.
The Southern Environmental Law Center, who filed the challenge, says the ordinance violates federal water quality law and North Carolina’s water quality laws. SELC considers the amount of 1.4 dioxane permitted under the order to leave the TZ Osborne Greensboro Wastewater Treatment Plant to be too high.
Among other things, the ordinance caps the amount of 1.4 dioxane, a stabilizing and degreasing solvent, which can leave the plant at 45 parts per billion the first year and 33 parts per billion the following year. The order also requires Greensboro to sample industrial wastewater for the purpose of detecting sources of contamination.
“We believe the landfill should be fully investigated and will continue to monitor the process,” said Jean Zhuang, an attorney for SELC. “These 1.4 dioxane peaks are not expected to occur.”
High levels reach Pittsboro
On June 30, Greensboro officials said they detected a release of 1.4 dioxane at the TZ Osborne processing plant that measured up to 687 parts per billion, which is nearly 20 times the amount that the US Environmental Protection Agency considers it safe for consumption. the water.
The contaminant left the South Buffalo Creek plant and spilled into the Haw River, where the city of Pittsboro gets its drinking water.
The city issued a press release on Monday that showed 93.6 parts per billion of 1.4 dioxane entering the city’s raw water – water before treatment – at a testing site on July 6. . A sample of treated drinking water measured 57.6 parts per billion at the same time. place of test.
The EPA does not regulate 1.4 dioxane but has set a health notice of 35 parts per billion. At this level of consumption over a lifetime, the EPA estimates that one in 10,000 people will develop cancer. North Carolina’s drinking water standard for surface water is 0.35 parts per billion. At this level, one in 1 million people would be expected to have cancer.
Greensboro says Shamrock is not to blame
Two years ago, Greensboro detected an even larger release of 1.4 dioxane leaving its wastewater treatment plant. After the press release, which prompted the DEQ’s consent order, the city identified Shamrock Environmental Corp. as the responsible party.
But this time around, Elijah Williams, the city’s water harvester, reiterated in an email on Tuesday that he doesn’t think Shamrock is responsible for the latest landfill. The company provides environmental decontamination services to other industries.
Williams says Shamrock is probably not to blame even though a “canal take” of the company’s sewer waste showed a concentration of 1.4 dioxane at 466 parts per billion on July 7, according to a document that Williams shared with NC Health News and submitted to DEQ.
Williams said the dilution factor would have significantly reduced the level of 1.4 dioxane before it reached the Greensboro processing plant. For Shamrock to be responsible, he said, 1.4 dioxane would have to have been released measuring in the thousands of parts per billion.
A press release from Pittsboro City Manager Chris Kennedy said his staff believe test samples of the city’s drinking water since the spill “indicate a delayed or secondary inflow of 1.4 dioxane reaching the Pittsboro raw water intake with what appears to be an additional slug of contamination from Greensboro on or immediately before July 6.
According to the press release, the city is returning water from its storage tanks more often in an attempt to rid the system of the contaminant. It also drained water from its Chatham Forest reservoirs.
Kennedy wrote that he is encouraged that the levels currently seen in the test samples, while still above detection levels, have dropped significantly.
“The city remains convinced that our water is safe to drink and use in residential and commercial applications,” he wrote.
Pittsboro is the only municipality to draw its drinking water from the Haw River. The Haw drains into lower Jordan Lake and then into the Cape Fear River, where nearly a million people get their drinking water.
When a similar spill was detected in Greensboro two years ago, the city failed to notify downstream water users, who detected high levels of the contaminant. Under DEQ regulations, the city was required to notify downstream cities.
After the last spill was detected, Greensboro said it promptly notified downstream water users. Fayetteville and Wilmington had not reported high levels of 1.4 dioxane but continue to test it.
The contaminant has historically been used as a solvent and solvent stabilizer. It is found in paint strippers, dyes, greases, antifreeze and deicers. It can also be found in some consumer products, including deodorants, shampoos, and cosmetics.
Since 1,4 dioxane is not regulated by the federal government, industries are not required to report a spill. Greensboro and other cities hold state pre-treatment permits that require them to notify DEQ when a release is detected.