A synthetic cyclic ether used as a solvent stabilizer (notably with 1,1,1-TCA) and as an unintended byproduct in surfactants. Highly mobile in groundwater, weakly sorbing, and resistant to conventional biological and air-stripping treatment.
1,4-Dioxane co-occurs with chlorinated solvent plumes from decades of industrial degreasing, where it was added to 1,1,1-trichloroethane as a stabilizer. It is also present at trace levels in many consumer surfactants and cosmetics as a manufacturing byproduct. Because it is fully miscible with water and barely sorbs to soil organics, dioxane plumes typically out-run the parent chlorinated solvent plume by a significant distance.
Standard pump-and-treat with granular activated carbon does not capture dioxane efficiently, and air stripping is ineffective due to its low Henry's constant. The technologies that work are advanced oxidation (UV/H2O2, UV/persulfate, ozone/peroxide), in-situ chemical oxidation with activated persulfate, supercritical water oxidation for concentrated streams, and high-temperature thermal desorption for soil. Regulatory drinking-water health advisories sit in the low microgram-per-litre range in multiple jurisdictions.
Also known as: 1,4-dioxane, dioxane.
1,4-Dioxane: treatment approach
A cyclic ether historically used as a stabilizer for chlorinated solvents (particularly 1,1,1-TCA) that is now recognized as a persistent, mobile groundwater co-contaminant requiring advanced oxidation or synthetic media rather than conventional pump-and-treat.
Per- and polyfluoroalkyl substances: a class of more than 12,000 synthetic compounds built around exceptionally stable carbon-fluorine bonds. PFAS is the family name, not a single chemical. PFOA and PFOS are two specific members of this class.
Perfluorooctanoic acid: a specific eight-carbon long-chain PFAS compound, historically used in non-stick coatings and AFFF firefighting foam. Classified by IARC in 2023 as Group 1, carcinogenic to humans.
Perfluorooctane sulfonic acid: a specific eight-carbon long-chain PFAS compound, historically the active surfactant in 3M Scotchgard and AFFF firefighting foam. Classified by IARC in 2023 as Group 2B, possibly carcinogenic to humans.
Polychlorinated dibenzo-p-dioxins and related furans: highly persistent, fat-soluble chlorinated compounds formed as unintended byproducts of combustion, chlorine-based manufacturing, and herbicide production, with TCDD among the most toxic substances ever characterized.