Original Broadcast: June 5, 2018

Slide Decks:

• ASDWA Webinar – Introduction
• New Hampshire – 1-4 Dioxane – Brandon Kernen
• North Carolina – Dioxane June_2018 – Rebecca Sadosky

The purpose of the webinar is to share information about state efforts to assess and address 1,4-dioxane, an unregulated contaminant that is causing states and water utilities to become increasingly concerned about potential health impacts from elevated levels of 1,4-dioxane in both groundwater and surface water drinking water sources.  This webinar also builds on the efforts of ASDWA, the Association of Clean Water Administrators (ACWA), the Ground Water Protection Council (GWPC), and EPA to share and promote Clean Water Act and Safe Drinking Water Act (CWA-SDWA) coordination activities across state and EPA water programs.

Intended Audience:  State, interstate, tribal, and federal water programs, water utilities, technical assistance providers, and anyone else who would like to participate.

Agenda

New Hampshire:  Brandon Kernen will present how the solvent stabilizer 1,4-dioxane has emerged as an unexpected groundwater contaminant at many sites and in drinking water supplies in New Hampshire and nationally. Although this contaminant has been used as a stabilizer for certain types of chlorinated solvents, most historic groundwater monitoring and remediation did not adequately address this contaminant. Additionally, 1,4-dioxane is an impurity in numerous personal care products and has been detected in treated municipal wastewater effluent. Over the last ten years, toxicity assessments coupled with new analytical techniques which achieve lower reporting limits for this compound have revealed that this highly mobile, recalcitrant and probable carcinogenic contaminant warrants the attention of drinking water professionals. This presentation will cover:

• Uses, sources, occurrence and fate and transport of 1,4-dioxane
• Toxicity information and federal and state regulations and guidance
• Laboratory analytical techniques
• Examples of contaminated sites and sources of drinking water
• Treatment options and costs

North Carolina:  Rebecca Sadosky will present information about efforts by the North Carolina Division of Water Resources to assess and address 1,4-Dioxane in multiple river basins throughout the state. These efforts included a two-year study that was collaboratively designed by Safe Drinking Water Act and Clean Water Act staff to examine ambient concentrations, identify potential sources, and document water quality improvements due to abatement efforts of 1,4-dioxane in major surface waters of the Cape Fear River basin. Three of the four study areas were located immediately downstream of domestic wastewater treatment facilities, indicating that these facilities were likely conduits for 1,4-dioxane from industrial sources into surface water. The study findings were communicated to effected municipalities, project partners, and the interested public.  During the second year of the study, quarterly sampling indicated a reduction of 1,4-dioxane concentrations in many areas of the basin. Further reductions will be necessary to achieve federal and state health advisory levels for 1,4-dioxane in drinking water supplies. The Division of Water Resources study is continuing in the Cape Fear River basin and has now expanded into the Yadkin and Neuse River basins.