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浙江大學環境與資源學院何豔教授團隊研究了CH4相關的生物過程在添加林丹的淹水水稻土自淨化過程中的作用，相關成果發表於Journal of Hazardous Materials（IF=9.038）。
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•CH4 promotes lindane dechlorination and methanogenesis in anaerobic soil.
•Sterilization leads to microbial diversity loss and functional recession.
•Microbial loss promotes lindane removal, methanogenesis and Fe reduction.
•Lindane dechlorination is synchronously coupled to methanogenesis.
Reductive dechlorination, an efficient pathway for complete removal of organic chlorinated pollutants (OCPs), is commonly reported to be coupled to oxidation of methane (CH4) or methanogenesis in anaerobic environments. However, the relationship between dechlorination and CH4-associated bioprocesses is unclear. Based on the hypothesis that CH4 supplementation could facilitate OCP dechlorination, we investigated the role of CH4-associated bioprocesses in the self-purification of flooded lindane-spiked paddy soils. Four treatments were conducted for up to 28 days: sterilized soil (S), sterilized soil + CH4 (SC), non-sterilized soil (NS), and non-sterilized soil + CH4 (NSC). Results indicated that both sterilization and addition of CH4 promoted lindane degradation and CH4 emissions in the flooded paddy soils. In the NS treatment, lindane had the lowest degradation rate when CH4 emissions were barely detected; while in the SC treatment, lindane had the highest degradation rate when CH4 achieved its highest emissions from anaerobic soil. Also, sterilization led to microbial diversity loss and functional recession, but increased ferrous ion [Fe(II)] concentrations compared to non-sterilized soils. Methanogenic communities and mcrA gene recovered faster than the majority of microorganisms (e.g., Fe bacteria, Bdellovibrionaceae, Rhizobiaceae, Dehalogenimonas) or functional genes (e.g., Dhc, Geo, narG, nirS). Collectively, we assume the enhanced removal of lindane may partly be due to both abiotic dechlorination promoted by chemical Fe redox processes and methanogenesis-derived biotic dechlorination. Revealing the coupling between dechlorination and CH4-associated bioprocesses is helpful to resolve both pollution remediation and mitigation of CH4 emissions in anaerobic contaminated sites.
還原脫氯是完全去除有機氯化汙染物（OCPs）的有效途徑，常被報導與甲烷（CH4）氧化或厭氧環境中的甲烷生成相關。然而，脫氯與CH4相關的生物過程之間的關係尚不清楚。基於補充CH4可以促進OCPs脫氯的假設，本文研究了CH4相關的生物過程在添加林丹的淹水水稻土自淨化過程中的作用，滅菌土壤（S）、滅菌土壤+ CH4 （SC）、未滅菌土壤（NS）和未滅菌土壤+ CH4 （NSC） 4個處理持續28 d。結果表明，滅菌土壤和CH4的添加均促進了淹水水稻土的林丹降解和CH4排放。NS處理下，幾乎檢測不到CH4排放的同時，林丹的降解速率最低；而SC處理下，林丹降解速率在厭氧土壤CH4排放最高時最高。與未滅菌的土壤相比，滅菌導致土壤微生物多樣性喪失和功能衰退，但鐵離子[Fe(Ⅱ)]濃度增加。產甲烷菌群和mcrA基因的恢復速度快於大多數微生物（如鐵細菌、Bdellovibrionaceae、Rhizobiaceae、Dehalogenimonas）和功能基因（如Dhc、Geo、narG、nirS）。綜上所述，本文認為林丹去除效果增強的部分原因可能是化學鐵氧化還原過程導致的非生物脫氯作用和甲烷生成導致的生物脫氯作用。研究揭示了脫氯與CH4相關生物過程的耦合關係有助於解決厭氧汙染場地的汙染修復和減緩CH4排放。
責任編輯：宋瀟
校對和審核：張陽 王農
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