High levels of 1,4-Dioxane could contaminate the drinking water for Pittsboro as early as today, prompting town officials to activate its emergency response, which includes extensive sampling and testing of the drinking water.
As Policy Watch reported Thursday evening, the contaminated discharge originated upstream, at Greensboro’s TZ Osborne wastewater treatment plant.
The plant sent effluent containing levels of the likely carcinogen — 20 times higher than the EPA health advisory goal — into South Buffalo Creek, a tributary of the Haw River.
The Haw River is the drinking water supply for the Town of Pittsboro, then drains into Jordan Lake and southeast into the Cape Fear River. Both the lake and the Cape Fear provide drinking water for hundreds of thousands of people, including residents of Cary, Apex, Fayetteville and Wilmington.
Preliminary sampling results show that levels of the likely carcinogen ranged from 543 parts per billion to 687 parts per billion in the wastewater. The EPA’s drinking water health advisory level is 35 parts per billion; in surface water the level is 0.35 parts per billion.
There is no EPA drinking water standard for 1,4-Dioxane; however, discharging these contaminants into waterways violates the Clean Water Act, according to the Southern Environmental Law Center.
Kent Jackson, engineering director for the town of Pittsboro, told Policy Watch via email that the public utilities office is “very aware of this unfortunate occurrence,” adding that town staff has been in “steady contact” with multiple agencies including City of Greensboro, the NC Public Water Supply Section, and Haw River Assembly. “Our staff will continue to monitor and manage this incident until the threat is mitigated.”
Because of past problems with 1,4-Dioxane leaving the TZ Osborne plant, Greensboro officials regularly sample for 1,4-Dioxane. The city notified the NC Department of Environmental Quality of the exceedances yesterday afternoon. This discharge does not affect Greensboro’s drinking water quality.
Byproducts are found in many goods, according to the EPA, including paint strippers, dyes, greases, antifreeze and aircraft deicing fluids, and in some consumer products, such as deodorants, shampoos and cosmetics.
Elijah Williams, water reclamation manager for the City of Greensboro, told Policy Watch via email that it is investigating potential sources of the contamination. Sampling results are due at the end of next week; based on those findings, if the city can confirm the origin of the contamination it will release the that information, Williams said. After a similar incident involving 1,4-Dioxane two years ago, the city disclosed the source — Shamrock Environmental — weeks later and only under pressure from the public and state environmental issues.
While DEQ regulates wastewater treatment plants through stipulations in their discharge permits, the individual utilities regulate their industrial and residential customers.
Yesterday’s discharge violates a Special Order by Consent between DEQ and the City of Greensboro, which set a maximum daily level of 45 parts per billion for 1,4-Dioxane. The consent agreement requires Greensboro to notify DEQ within 24 hours if for concentrations above that figure. The city was also fined $5,000 related to the 2019 discharge.
The Southern Environmental Law Center is contesting the consent order on behalf of the Haw River Assembly. The SELC argues that the order fails to comply with the applicable state water quality laws and regulations, and, “allows Greensboro to significantly increase discharges of the toxic chemical into a river that is a drinking water supply for thousands of North Carolinians, which contributes to a violation of water quality standards.”
Rain moved in to the area overnight, but it’s unclear whether it will sufficiently dilute the amount of 1,4-Dioxane in the drinking water supply. Heavy rain also increases the velocity of the river flow, which means any contamination could reach Pittsboro more quickly.