Biochar-assisted detoxification of groundwater trichloroethene: Mitigating vinyl chloride accumulation and environmental risks via Dehalococcoides mccartyi-containing consortium.

The persistent contamination of groundwater by trichloroethene (TCE) and its highly carcinogenic intermediate vinyl chloride (VC) poses a serious threat to drinking water safety and ecosystem health. A critical limitation of many microbial approaches is the incomplete dechlorination of VC to ethene. This study presents a remediation strategy that integrates biochar derived from Zizania latifolia (water bamboo) husks with a native microbial consortium enriched in Dehalococcoides mccartyi (Dhc) strain CWV2, a strain capable of completely dechlorinating VC to non-toxic ethene. Biochar (BC600) demonstrated optimal adsorption while enhancing microbial colonization and activity, leading to accelerated TCE degradation and >50 % reduction of VC accumulation. Microbial community analysis further indicated that biochar promoted syntrophic hydrogen producers and electroactive bacteria, ensuring long-term dechlorination stability. This combined strategy not only increases pollutant removal efficiency but also reduces the environmental and health risks associated with VC accumulation, thereby offering a sustainable pathway for aquifer restoration.