海洋渔业2025，Vol.47Issue(4)：496-506,11.
长江口沉积物-水界面溶解态砷的粒级特征及迁移转化过程
Size fractions and migration-transformation of arsenic at the sediment-water interface in the Changjiang Estuary
摘要
Abstract
To understand the migration and transformation mechanisms of arsenic(As)at the sediment-water interface(SWI),this study investigated the vertical distribution of size-fractionated dissolved As(dAs),including soluble As(sAs)and colloidal As(cAs),across the overlying water and porewater at four sites(A5-1,A5-2,A5-3 and A6-2)in the Changjiang Estuary during summer of 2023.Depth-dependent variations in sedimentary As speciation were also determined to further elucidate As migration and transformation processes at the SWI.Additionally,diffusive fluxes of different dAs fractions were estimated to assess sediments as a source or sink to dAs in the Changjiang Estuary.Results showed that porewater dAs concentrations ranged from 0.063 to 1.106 μmol·L-1,and sAs was the dominant form,accounting for 37.0%-93.3%.Total As contents in sediments were 3.94-7.31 μg·g-1,with fraction of As bound to Fe/Mn(oxyhydr)oxides accounting for more than 61%of the total extractable As fractions.A"scavenging-release-scavenging"pattern was observed in the vertical profiles of porewater dAs,opposite to the depth-dependent variations of Fe/Mn-bound As in sediments,indicating that the removal of dAs in the surface and deep layers of porewater in the Changjiang Estuary was predominantly controlled by Fe and Mn(hydro)oxide adsorption and sulfide binding,respectively.Compared to sAs,the vertical variations of cAs were more similar to those of dAs,suggesting that cAs was more susceptible to adsorption onto Fe oxides.Dissolved As concentrations,including sAs and cAs,in the porewater were higher than those in the overlying water,indicating an upward diffusion of dAs across the SWI.The annual dAs flux across the SWI in the Changjiang Estuary was 1.61×108 g,with sAs accounting for 83.6%.The results can provide a scientific basis for ecological risk assessment and As pollution control in the Changjiang Estuary.关键词
溶解态As/固相As形态/迁移转化过程/扩散通量/沉积物-水界面Key words
dissolved As/solid As speciation/migration and transformation/diffusive flux/sediment-water interface分类
资源环境引用本文复制引用
刘晓淇,段丽琴,宋金明,李学刚,袁华茂..长江口沉积物-水界面溶解态砷的粒级特征及迁移转化过程[J].海洋渔业,2025,47(4):496-506,11.基金项目
国家自然科学基金(42476037,41976037) （42476037,41976037）
泰山学者工程项目(tsqn202211256) （tsqn202211256）
国家重点研发计划(2023YFE0106200) （2023YFE0106200）
