Consumer panel estimates of odor thresholds for crude 4‐methylcyclohexanemethanol

On Jan. 9, 2014, a spill of “crude” 4‐methylcyclohexanemethanol (MCHM) into the Elk River in West Virginia contaminated the water supply for 300,000 people. The crude MCHM caused an intense licorice odor in the drinking water that supplied the area in and around Charleston, W.Va. A sensitive analytical method developed by a commercial laboratory was used to verify the concentrations of crude MCHM presented to a consumer panel selected using specific criteria. The method used for the panel studies was ASTM E679‐04, which has been used to determine other odor thresholds in water. The odor threshold and odor recognition concentrations for crude MCHM in water were estimated by the consumer panel to be 0.55 and 7.4 μg/L, respectively. Two estimates of the odor objection concentration were 7.7 and 8.8 μg/L.