WILMINGTON, N.C. (WECT) – Results of water samples tested from July 1 through July 6 show 1,4-dioxane level below the detection limit.
Samples have been taken daily by CFPUA since July 1 when the City of Greensboro reported high levels of the toxin in discharge from the T.Z. Osborne Wastewater Treatment Plant.
The discharge from the Greensboro plant, which undergoes significant dilution, eventually flows into the Cape Fear River.
Analysis from CFPUA’s contract lab typically takes about two weeks to detect 0.07 ppb of 1,4-dioxane, so CFPUA requested expedited results at a higher detection limit of 2 ppb.
As of July 7, the level of 1,4-dioxane detected was below the 2 ppb in all daily samples of raw Cape Fear River water and finished water treated at the Sweeney Water Treatment Plant.
Separate samples were also sent for higher resolution analysis; results from these tests are expected by this Friday or by Monday, July 12.
The industrial solvent, 1,4-dioxane, is considered to be a likely carcinogen by the U.S. Environmental Protection Agency. Although this toxin is not regulated, the EPA suggests there is a one in one million cancer risk from a lifetime exposure to 1,4-dioxane at a concentration of 0.35 ppb.
According to CFPUA, “Ozonation and biological filters at Sweeney typically achieve about two-thirds removal of 1,4-dioxane from raw water during treatment.”
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