Determination of (4-methylcyclohexyl)methanol isomers by heated purge-and-trap GC/MS in water samples from the 2014 Elk River, West Virginia, chemical spill.

A heated purge-and-trap gas chromatography/mass spectrometry method was used to determine the cis- and trans-isomers of (4-methylcyclohexyl)methanol (4-MCHM), the reported major component of the Crude MCHM/Dowanol™ PPh glycol ether material spilled into the Elk River upriver from Charleston, West Virginia, on January 9, 2014. The trans-isomer eluted first and method detection limits were 0.16-µg L(-1)trans-, 0.28-µg L(-1)cis-, and 0.4-µg L(-1) Total (total response of isomers) 4-MCHM. Estimated concentrations in the spill source material were 491-g L(-1)trans- and 277-g L(-1)cis-4-MCHM, the sum constituting 84% of the source material assuming its density equaled 4-MCHM. Elk River samples collected⩽3.2 km downriver from the spill on January 15 had low (⩽2.9 µg L(-1) Total) 4-MCHM concentrations, whereas the isomers were not detected in samples collected 2 d earlier at the same sites. Similar 4-MCHM concentrations (range 4.2-5.5 µg L(-1) Total) occurred for samples of the Ohio River at Louisville, Kentucky, on January 17, ∼630 km downriver from the spill. Total 4-MCHM concentrations in Charleston, WV, office tap water decreased from 129 µg L(-1) on January 27 to 2.2 µg L(-1) on February 3, but remained detectable in tap samples through final collection on February 25 indicating some persistence of 4-MCHM within the water distribution system. One isomer of methyl 4-methylcyclohexanecarboxylate was detected in all Ohio River and tap water samples, and both isomers were detected in the source material spilled.