Evaluation of 1,4-dioxane attenuation processes at the Gelman Site, Michigan, USA.

1,4-Dioxane released at the Gelman Site in Washtenaw County, Michigan, produced a series of contaminant plumes migrating up to 3 km through a heterogenous glacial aquifer system. An analysis of 1,4-dioxane concentrations in the Eastern Area of the Gelman Site between 2011 and 2017 documented a mass balance deficit of 2200 kg in excess of 2100 kg of 1,4-dioxane removed via remediation. Five mechanisms were evaluated to account for the mass deficiency: sorption, matrix diffusion, biodegradation, surface discharge, and bypass of the existing monitoring well network.

Determination of 1,4-dioxane in water samples using freeze-assisted liquid-liquid extraction and gas chromatography-mass spectrometry with select reaction monitoring.

In this study, we developed an analytical method for the determination of 1,4-dioxane in aqueous solutions using freeze-assisted liquid-liquid extraction, also known as frozen microextraction, and gas chromatography with triple quadrupole mass spectrometry with select reaction monitoring. The method is capable of quantifying 1,4-dioxane across a broad range of concentrations (1-10 000 μg/L) relevant to contaminated sites, with an instrument detection limit and method detection limit experimentally verified as 2.1 and 2.