Bioremediation of organohalide and heavy metal co-contamination: from individual challenges to integrated synergistic solutions
摘要
The co-occurrence of organohalides and heavy metals constitutes a pervasive environmental challenge in anthropogenically impacted settings such as industrial complexes, electroplating facilities, and e-waste recycling sites. Owing to their persistence, toxicity, and chemical recalcitrance, these co-contaminants pose substantial ecological and human health risks while markedly increasing the complexity of remediation. Conventional physicochemical treatments are frequently insufficient to address their combined presence, especially given the synergistic inhibitory interactions that undermine removal efficiencies. As a result, microbially mediated synergistic bioremediation has garnered considerable attention as a sustainable alternative capable of achieving concurrent detoxification. Within these systems, organohalide-respiring bacteria (OHRB) play a key role by transforming organohalides into non-halogenated products that are more readily subjected to biotoxicity reduction. In parallel, sulfate-reducing bacteria (SRB) facilitate heavy metal immobilization through sulfide-mediated precipitation while simultaneously supplying electron donors (e.g., acetate, hydrogen) that sustain OHRB metabolism. These intertwined carbon–sulfur metabolic networks support the formation of stable, functionally complementary microbial consortia, enhance dehalogenation kinetics, and alleviate heavy metal toxicity. This review integrates current advances in understanding the occurrence, ecological impacts, and microbial mechanisms governing the co-remediation of organohalide–heavy metal contamination. Special emphasis is placed on characterizing the functional roles, metabolic coordination, and syntrophic interactions among key microbial guilds. Collectively, these insights provide a mechanistic foundation for the rational design of targeted, efficient, and ecologically robust synergistic bioremediation strategies for complex co-contaminated environments.