流路帯におけるFe-S酸化還元帯状構造とBDE-47の自然減衰に影響を与える微生物群集の誘導を誘発する堆積物テクスチャ

This study investigated the attenuation of 2,2',4,4'-tetrabromo-diphenyl ether (BDE-47) in laboratory-scale upflow columns simulating hyporheic zones (HZ) with a focus on how sediment texture governs Fe-S redox zonation, microbial community assembly, and debromination dynamics. A ∼10 % difference in silt-clay content between two artificial sediments was identified as the key factor driving divergent microbial niches and degradation pathways. The coarser column (SS) promoted rapid initial BDE-47 attenuation (weeks 5-9) via enhanced iron reduction, however, the finer column (SCS) achieved an accelerated late-stage efficiency (3.42 µg week^-1, 12.7-fold higher than SS) during weeks 9-12, driven by intensified sulfate reduction and most pronounced at the 25 cm middle layer. Conserved aerobic-anaerobic co-abundance networks supporting facultative dehalorespiration through fermentative syntropy and Fe-S cycling, predominantly mediated by Desulfuromonas, were selectively shaped by sediment texture, thereby regulating the efficiency and timing of PBDE biodegradation. Notably, a Zoogloea-Flavobacterium-Legionella triangle bridging module in SS was identified as an indirect biofilm-mediated facilitation mechanism for PBDE debromination. This study advances our understanding of microbial debromination in heterogenous porous media, thereby providing a physico-ecological mechanistic basis for engineering HZ barrier systems against halogenated persistent organic pollutants like PBDEs.