1,4-dioxane is an emerging contaminant of concern that was monitored in drinking water throughout the United States as part of the U.S. Environmental Protection Agency’s Third Unregulated Contaminant Monitoring Rule. In October 2016, the state Division of Water Resources completed the second year of a study designed to examine concentrations and identify potential sources of 1,4-dioxane in surface waters of the Cape Fear River basin.
Results from the study's first year indicated four primary areas of elevated 1,4-dioxane in the upper portion of the Cape Fear River basin. Three of these areas were located immediately downstream of wastewater treatment plants, indicating that discharges from these facilities may be conduits for 1,4-dioxane. The fourth was located further downstream from a treatment plant, so potential local sources will also be explored as the study continues. Results from the study's second year demonstrated reductions in 1,4-dioxane concentration at almost all monitoring stations.
The Division of Water Resources continues to monitor 1,4-dioxane at locations in the Cape Fear River basin, with the objectives of further understanding changes in concentrations, identifying potential sources of the compound, and documenting data that will help the state develop a regulatory strategy. Funding has recently become available to expand the study to include monitoring in the Neuse and Yadkin river basins.
Data collected from established DWR ambient water quality monitoring stations
1,4-Dioxane and Bromide Monitoring Plan (beginning Fall 2017)