Industrial Spills and Water Distribution: Crude MCHM Sorption and Desorption in Polymer Pipes and Linings

Abstract

In response to industrial chemical spills that potentially contaminate drinking water and distribution systems, this study investigated sorption and desorption of odorous crude [(4-methylcyclohexyl)methanol] (MCHM) into polyethylene pipes, epoxy, or polyurethane linings, and granular activated carbon. MCHM sorption was compared to toluene and 1-butanol, which were investigated as reference contaminants. MCHM is the licorice-smelling industrial chemical that contaminated drinking water for over 300,000 West Virginians in 2014. For polyethylene pipes, MCHM diffusivity was 0.36–1.36×10−9 cm2/s and solubility was 0.003–0.008 g/cm3. Sorbed MCHM readily desorbed from polyethylene into water at levels above the odor threshold. MCHM diffused more rapidly into epoxy at 35×10−9 cm2/s, although its solubility was similar to that of polyethylene pipes. MCHM caused polyurethane to swell and deform. Granular activated carbon sorbed MCHM to below its odor threshold as determine by the Total Intensity of Odor method. Sorption properties of MCHM into polyethylene were similar to the polar contaminant 1-butanol and dissimilar to the nonpolar contaminant toluene, which is known to exhibit rapid diffusivity and high solubility.