Managing Emerging Compounds in Water

The N.C. Division of Water Resources is implementing several projects associated with compounds of concern, or emerging compounds. Studies were done in 2018 to characterize the presence of these compounds in various water supply reservoirs and an effort is underway to develop an overall management strategy to reduce the levels of these compounds in the Cape Fear River Basin. 

1,4 Dioxane Investigation in the Cape Fear River

1,4 Dioxane Investigation in the Cape Fear River

Since 2014, the Division of Water Resources has been sampling for 1, 4 dioxane in the Cape Fear River Basin, after seeing elevated concentrations reported as part of the Environmental Protection Agency’s Third Unregulated Contaminant Monitoring Rule (UCMR3).

Elevated levels of 1,4 dioxane were identified downstream of the Greensboro, Reidsville, and Asheboro wastewater treatment plants, and DWR has worked in collaboration with those facilities to reduce the discharge. To help facilitate the effort, DWR required all three cities to submit corrective action plans outlining steps to reduce the substance from their discharge. DWR also encouraged the pretreatment programs in the Cape Fear Basin to have the Division of Environmental Assistance and Customer Service’s Waste Reduction Partners work with their industry dischargers to reduce or eliminate their 1,4-dioxane effluent.  

DEQ is also requiring publicly owned utilities with pretreatment programs and industrial dischargers in the Cape Fear River Basin to screen for a set of emerging compounds in wastewater. In addition, DEQ is working to determine and assess the additional sources of 1,4 dioxane contribution in the basin beyond the dischargers, that may be causing contaminated groundwater to infiltrate into surface water. 

Monthly sampling for 1,4 dioxane has been collected by the permittees once per month since Dec. 2017 and submitted on the discharge monitoring reports. The see the discharge monitoring report data, go to the interactive map.

Weekly sampling for 1,4 dioxane at the Greensboro and Reidsville wastewater treatment plants was initiated when DWR learned about the elevated levels of 1,4 dioxane in Pittsboro’s drinking water in October 2019. In early November, staff also started sampling at the East Burlington wastewater treatment plant on the Haw River. That data will be released once it has been reviewed. 

On November 14, DEQ issued notices of violation to the wastewater pre-treatment programs for the cities of Greensboro and Reidsville for recent 1,4 dioxane discharges that violated water quality standards and the conditions of their wastewater permits.

Links to NPDES permit information for Greensboro, Reidsville and Asheboro

Greensboro NPDES permit documents

Reidsville NPDES permit documents 

Asheboro NPDES permit documents 

News Releases about the ongoing investigation

Nov. 15, 2019: DEQ issues violation notices to Greensboro and Reidsville for 1,4 dioxane discharges

Oct. 22, 2019: DEQ investigating 1,4 dioxane levels from Reidsville, notifying utilities

Oct. 15, 2019: DEQ Investigating 1,4 Dioxane Release

Management Strategy for Industrial Dischargers and Pretreatment Facilities

Management Strategy for Industrial Dischargers and Pretreatment Facilities

State environmental officials are requiring publicly owned utilities with pretreatment programs and industrial dischargers in the Cape Fear River Basin to screen for a set of emerging compounds in wastewater. Influent sampling results from the 25 publicly owned utilities were due on Oct. 31. Sampling results from the industrial dischargers are due on Jan. 31.

The N.C. Division of Water Resources (DWR) sent letters to municipalities with pretreatment programs to conduct screening for 1,4 dioxane and per- and polyfluoroalkyl substances, known as PFAS, for three consecutive months starting in July. The division also sent letters to industrial dischargers in the area requiring them to monitor for total PFAS once per month, for three consecutive months, starting in October. This effort is part of an ongoing management strategy to address some of these compounds in surface water.

The influent sampling results from the 25 Publicly Owned Treatment Works (POTWs) that have pretreatment programs and discharge in the Cape Fear River Basin are contained and presented in the following map. The map shows each POTW and the water supply intakes located in the basin. DWR required sampling of the influent (or incoming wastewater stream) at these facilities because they receive wastewater from industrial sources that may contain 1,4 dioxane or one or more of the per- and polyfluoroalkyl substances known as PFAS.

1,4 Dioxane

The 1,4 dioxane influent sampling results from all 25 POTWs confirmed that three POTWs of primary concern belong to Greensboro, Reidsville, and Asheboro. The results from the remaining 22 POTWs samples were significantly lower and are not anticipated to cause levels at downstream water intakes to exceed the drinking water health advisory of 35 ug/L. Notices of Violations have been issued to Greensboro and Reidsville and additional monitoring and enforcement actions are underway to limit and enforce reductions of 1,4 dioxane in their discharge.

Asheboro’s corrective action plan states that an industrial user in their pretreatment program is installing best available treatment technology to reduce 1,4 dioxane in its discharge to the wastewater treatment plant in early 2020. Asheboro’s POTW does not directly discharge to a water supply.

PFAS Compounds

The PFAS influent sampling results from the 25 POTWs indicate that one facility is potentially affecting a downstream water intake. One sampling event at Sanford’s Big Buffalo POTW showed influent levels that may cause an instream concentration of PFOS, PFOA, or the sum of PFOS and PFOA to exceed EPA’s drinking water health advisory of 70 nanograms per liter (ng/L), or parts per trillion (ppt), at Sanford’s water supply intake. DEQ has initiated additional sampling and source identification measures with the city of Sanford.

Influent sampling results from the other 24 POTWs showed PFOS and PFOA at concentrations that would not cause a downstream water supply to exceed EPA’s drinking water health advisory of 70 ng/L at the intake.

Emerging compounds, such as 1,4 dioxane and PFAS, do not currently have federal water quality standards. Data collected and reviewed as part of the U.S. Environmental Protection Agency (EPA) Safe Drinking Water Act (SDWA) Third Unregulated Contaminant Monitoring Rule has indicated elevated concentrations of these compounds in drinking water that originated from the Cape Fear River Basin. In addition, monitoring performed by the state DWR has confirmed the presence of these compounds in surface waters within the Cape Fear River Basin.

1,4-dioxane is a clear liquid that is highly miscible in water. It has historically been used as a solvent stabilizer and is currently used for a wide variety of industrial and manufacturing purposes. The compound can be found in industrial solvents, paint strippers, and varnishes and is often produced as a by-product of chemical processes to manufacture soaps, plastics, and other consumer products. PFAS compounds are most often associated with nonstick coatings, plating operations, firefighting foams, and stain- and water-resistant treatments for clothing, furniture and carpeting.

Well Testing in New Hanover County

Well Testing in New Hanover County

DEQ continues to investigate the presence of PFAS compounds in groundwater wells located in New Hanover County.

DEQ staff have performed three rounds of sampling in public water supply wells and DEQ ambient monitoring wells since May, when Cape Fear Public Utility Authority (CFPUA) disclosed results of detections of PFAS in wells in their system. DEQ has shared results with CFPUA and other well owners. 

The detections of PFOA and PFOS in all of the public water supply wells were below the lifetime health advisory level set by the EPA in 2016 and GenX detections were below the provisional drinking water health goal set by DHHS in 2017.

DEQ will continue to sample public water supply wells, monitoring wells and surface water to further define the extent of the PFAS compounds.

Map of sampling locations.
Please note: The yellow diamonds reference monitoring wells and the blue squares reference public water supply wells.

Excel spreadsheet of results.

Surface Water Sampling 

Surface Water Sampling 

The Division of Water Resources performed three studies in 2018 to characterize the presence and concentrations of select emerging compounds (EC) in B. Everett Jordan Reservoir and its immediate watershedFalls Lake and its immediate watershed and in various public water supply (PWS) reservoirs in the Cape Fear, New and Watauga River Basins.

Monitoring continues across the state to further evaluate potential source areas as the division establishes PFAS analytical capabilities. The division will also use the UNC Policy Collaboratory’s data from drinking water intakes when available to help identify future sampling locations.

Analytical Results for PFAS Screening of Select Public Water Supply Reservoir