Listed by the United States Environmental Protection Agency (EPA) as an emerging contaminant, awareness surrounding 1,4-dioxane challenges continues to increase. Individuals from multiple industries have banded together in various working groups to explore 1,4-dioxane remediation strategies and develop practical guidance that can be applied at sites across the country. Notably, the Interstate Technology and Regulatory Council (ITRC) recently published a web-based technical and regulatory (Tech-Reg) guidance document dedicated to 1,4-dioxane that provides deeper insight into challenges and potential solutions.
Remind me – why does 1,4-dioxane present a challenge at sites?
1,4-dioxane is an industrial chemical that was primarily used historically as a stabilizer for solvents but is also a material or by-product of some production processes such plastics, surfactants, and others. Toxicological data indicates 1,4-dioxane is a probable human carcinogen. 1,4-dioxane has several unique properties that make the substance difficult to characterize and remediate. For example, 1,4-dioxane mixes easily with water and does not tend to “stick” to soil or evaporate into the air, meaning it can travel relatively long distances once introduced to groundwater. Additionally, 1,4-dioxane cannot be removed from water through otherwise proven processes, such as air stripping, that work for some other volatile contaminants of concern.
What does the current 1,4-dioxane regulatory framework look like?
1,4-dioxane has been listed as a hazardous substance since the early 1980s but was reclassified to an emerging contaminant in the early 2000s due to an EPA reassessment of the risk it poses to the environment. From there, it has been a closely watched contaminant. It has been added to the contaminant list under the Safe Drinking Water Act (SDWA) and is tracked by the EPA’s Uncontaminated Contaminant Monitoring Rule (UCMR). At this time, there is no federal-level regulatory framework regarding recommended surface water quality criteria or a maximum contaminant level (MCL) for 1,4-dioxane.
However, many states have enacted regulations regarding 1,4-dioxane including state-specific soil and groundwater standards. While only New York has a state MCL for 1,4-dioxane, many other states have enforceable cleanup levels. These are detailed in the ITRC Tech-Reg Section 2.2 with more details and links to state agency websites in Appendix A.
Tell me more about the new ITRC resources
The ITRC 1,4-Dioxane Project Team has worked to aggregate the latest 1,4-dioxane research, regulations, and field-scale experiences and translate these into easy-to-understand, useable guidance documents and resources. As with other ITRC teams, this group included regulators, consultants, academics, and members of industry. The results of this team’s work can now be found on the ITRC 1,4-dioxane website. The website provides free access to the detailed 1,4-dioxane Tech-Reg and the six summary-level fact sheets. The fact sheets include information on history of use and potential sources, regulatory framework, fate and transport in the environment, sampling and analysis, remediation, and toxicology / risk assessment.
Want a live overview of the new ITRC resources?
Starting March 25, 2021, ITRC will be hosting an internet-based training session with key materials from the 1,4-dioxane team. If you’re unable to attend the live webinar, ITRC plans to publish the trainings to the 1,4-dioxane website for ongoing reference. This training will be presented live again on September 30, 2021.
Trihydro commonly works on sites where 1,4-dioxane is a concern and has performed site characterization, data validation, technology screening, and remediation. Fritz Krembs, PE, PG, Senior Engineer/Geologist at Trihydro participates on ITRC’s 1,4-Dioxane Project Team, serving as the in situ remediation subgroup lead. Fritz is also on the training team and will be assisting with the ITRC 1,4-dioxane fall internet-based training. He is always available to discuss questions or concerns you have about 1,4-dioxane at your site.