Study Questions MCHM Toxicity Research

A new study of crude 4-methylcyclo­hexanemethanol (MCHM)—the chemical that spilled and tainted water supplies in West Virginia in January—indicates that it is more toxic to the freshwater indicator organism Daphnia magna than shown in previous studies. The work, which has not yet been published or peer reviewed, came from the lab of Andrew J. Whelton at the University of South Alabama, who reported the results at a July 10 national conference of public health officials. Whelton’s group exposed the organism to crude MCHM, and found a no observed effect level (NOEL) of 6.25 mg/L, in contrast with the 50 mg/L found in previous studies on D. magna performed by Eastman Chemical in 1998. The reasons for the different results are not yet clear. The newly reported toxicity levels are far higher than those found in drinking water after the spill. Whelton also cautioned that the study “has no relevance in humans.” Eastman says it has no reason to question the conclusion of the authors of the 1998 studies. Whelton says he hopes other labs will try to replicate the work.