MassDEP issued a fact sheet in June identifying special considerations for responding to releases of 1,4-dioxane (“dioxane”), which was primarily used as a stabilizer and corrosion inhibitor as an additive to chlorinated solvents but can also be erroneously detected because of its use in environmental sampling. 

Dioxane is not found naturally in the environment and has been classified by EPA as a likely human carcinogen, and can harm the human nervous system, liver and kidney.  Exposure is typically through ingestion of contaminated water.

MassDEP has found that dioxane is typically found at contaminated sites co-located with trichloroethylene or 1,1,1-trichlorethane.  However, it is still manufactured today and used in many products including cosmetics, shampoos, and other personal care products as well as pharmaceuticals.  As a result, it may be released into the environment through wastewater systems and septic systems.  Further, dioxane is often used in the development of groundwater monitoring wells and as a surfactant to decontaminate environmental sampling equipment.  Thus, dioxane may be detected at a site in error.

The MassDEP fact sheet suggests that groundwater sampling and analysis for dioxane is appropriate at locations with certain types of historic or current operations:  use or manufacture of chlorinated solvents, laboratories where dioxane may have been used as a reagent, landfills, military sites where chlorinated solvents were used, and airports that have used de-icing fluids. 

In addition, the fact sheet describes special analytical techniques that should be used to evaluate dioxane at appropriate detection levels.  Because dioxane may be used to decontaminate sampling equipment, MassDEP also suggests taking additional quality control samples to ensure that residual dioxane on sampling equipment is not erroneously identified as site-related. 

Finally, the fact sheet suggests that, because dioxane may move further in groundwater than the chlorinated solvents, sampling for dioxane should occur beyond the identified chlorinated solvent plume in order to identify the leading edge of the dioxane plume.  This evaluation may be complicated because “household/consumer products such as shampoos and detergents are known to contain high levels of 1,4-dioxane and can enter the environment through wastewater treatment plants and septic systems, assessment activities should ascertain where relevant, whether the source of 1,4-dioxane is from a release regulated under the [site cleanup program] or from other sources, such as septic systems.”