Natural\nAttenuation\nPotential of Vinyl Chloride and\nButyl Acrylate Released in the East Palestine, Ohio Train Derailment\nAccident

The\nEast Palestine, Ohio train derailment released toxic\nvinyl\nchloride (VC) and butyl acrylate (BA), which entered the watershed.\nStreambed sediment, surface water, and private well water samples\nwere collected 128 and 276 days postaccident to assess the natural\nattenuation potential of VC and BA by quantifying biodegradation biomarker\ngenes and conducting microcosm treatability studies. qPCR detected\nthe aerobic VC degradation biomarkers <i>etnC</i> in ∼40%\nand <i>etnE</i> in ∼27% of sediments collected in\nboth sampling campaigns in abundances reaching 10<sup>5</sup> gene\ncopies g<sup>–1</sup>. The 16S rRNA genes of organohalide-respiring <i>Dehalococcoides</i> and <i>Dehalogenimonas</i> were,\nrespectively, detected in 50 and 64% of sediment samples collected\n128 days postaccident and in 63 and 88% of sediment samples collected\n276 days postaccident, in abundances reaching 10<sup>7</sup> cells\ng<sup>–1</sup>. Elevated detection frequencies of VC degradation\nbiomarker genes were measured immediately downstream of the accident\nsite (i.e., Sulphur Run). Aerobic VC degradation occurred in all sediment\nmicrocosms and coincided with increases of <i>etnC</i>/<i>etnE</i> genes and <i>Mycobacterium</i>, a genus comprising\naerobic VC degraders. The conversion of VC to ethene and an increased\nabundance of VC reductive dechlorination biomarker genes were observed\nin microcosms established with sediments collected from Sulphur Run.\nAll anoxic microcosms rapidly degraded BA to innocuous products with\n intermediate formation of <i>n</i>-butanol and acrylate.\nThe results indicate that microbiomes in the East Palestine watershed\nhave natural attenuation capacity for VC and BA. Recommendations are\nmade to improve first-response actions in future contaminant release\naccidents of this magnitude.