An unwanted licorice odor in a West Virginia water supply

摘要

A spill of "Crude" 4-methylcyclohexanemethanol (MCHM) into the Elk River in West Virginia resulted in complaints by residents of an odor in their tap water downstream of the spill-predominantly a licorice odor. The area affected by the licorice odor included Charleston, W.Va., and a surrounding nine-county area. A team of experts was hired to understand the odor characteristics of the spilled chemical. The expert team developed a methodology based on ASTM Standard E679-04 (2011) to estimate the odor threshold concentration (OTC), odor recognition concentration (ORC), and odor objection concentration (OOC) for Crude MCHM in water during a single panel session.An expert panel estimated an OTC of less than 0.15 μg/L, an ORC of 2.2 μg/L, an OOC based on a degree-of-liking scale of 4.0 μg/L, and an OOC based on objection/complaint of 4.0 μg/L. The estimated OTC is in the realm of nanograms per litre, an extraordinarily low concentration. The ability of the expert human nose to detect this compound is far greater than any analytical method currently available.