钝化-疏浚协同抑制太湖底泥总磷释放研究OA

Taihu lake,one of China's largest freshwater bodies,has been experiencing severe eutrophication and endogenous pollution in recent years,with sediment phosphorus release identified as a key driver of water quality degradation.Although traditional dredging can re-move nutrient-rich sediments,construction disturbance often leads to secondary pollution.To address this issue,this study innovatively integrates chemical passivation with dredging by employing polyaluminum chloride(PAC)as the passivating agent.Batch simulation ex-periments determined the optimal PAC dosage to be 4 g/kg.Results demonstrated that this passivation-dredging approach effectively inhibited the release of total phosphorus(TP)from sediments,achieving removal rates of 82.8%in Yueliang Bay and 62.6%in Meiliang Bay.Furthermore,PAC treatment improved the physicochemical properties of the overlying water by stabilizing pH,decreasing the oxidation-reduction potential(ORP),and reducing conductivity fluctuations,thereby mitigating the impacts of dredging disturbance.High-throughput 16S rRNA gene sequencing further revealed that PAC addition altered the micro-bial community structure in sediments by reducing the abundance of sulfur-cycling bacteria and promoting heterotrophic and nutrient-transforming taxa,which enhanced overall sys-tem stability.This study demonstrates that the synergistic passivation-dredging technique can effectively mitigate secondary pollution risks,providing both technical and microbiologi-cal support for large-scale ecological dredging in Taihu lake and other eutrophic water bodies.