椒江沉积物的重金属分布特征及环境评价  

Distribution and pollution assessment of heavy metals in the sediments of Jiaojiang River

作　　者：吴舟扬 杨守业[1] 苏妮[1] 郭玉龙[1] 毕磊[1] 

机构地区：[1]同济大学海洋与地球科学学院海洋地质国家重点实验室,上海200092

出　　处：《海洋地质与第四纪地质》2018年第1期96-107,共12页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金"河流与海洋沉积地球化学:末次冰盛期以来东海沉积中长江源物质的源汇过程与环境意义"(41225020);科技部"典型中小入海河流河口动力沉积地貌与环境本底数据调查"项目(2013FY112200);"上海市优秀学科带头人计划"(14XD1403600)

摘　　要：沉积物对水体中的重金属具有源和汇的双重作用。河流沉积物中重金属含量与相态分析是研究流域重金属元素循环,评价其生态危害性的基本方法。采用1mol/L的盐酸对椒江悬浮物和河漫滩沉积物进行淋滤,研究重金属(Zn、Pb、Cr、Cu和Cd)在酸溶相和酸不溶相中的分布特征,分析并揭示其主要来源和生态效应。椒江沉积物中Zn、Pb、Cu、Cd的含量明显高于浙东地区土壤背景值,酸淋出率>60%,当环境条件发生变化时,酸溶相中的重金属易释放到水体中,具有较高的生态风险。相关性和主成分分析揭示,酸溶相中的重金属主要吸附、络合于有机质和铁锰氧化物中,其来源受工业、农业排放的控制。富集因子分析和潜在生态危害评价表明,椒江沉积物中Cd的富集程度最高,尤其在上游永安溪河段,Cd达到显著富集。而Zn、Pb、Cr、Cu均为轻度—中度富集。The river sediment acts not only as the major carrier but also the secondary sources of heavy metal contamination in river water.Elemental concentrations and chemical phases are essential to the study of heavy metal contamination in rivers and the evaluation of their ecological risks.In this study,1 mol/L hydrochloric acid（HCl）is used to leach heavy metals out from the samples（including both floodplain sediment and suspended particulate matter）collected from the Jiaojiang River,aiming to investigate the distribution of heavy metals（Zn,Pb,Cr,Cu and Cd）in acid-soluble and acid-insoluble phases,and thus to explore the major sources of heavy metals and their ecological risks.The concentrations of Zn,Pb,Cu and Cd in the Jiaojiang sediments are significantly higher than the local background values and their leaching rates,the ratios of elemental concentrations in the leachate to those in bulk samples,are higher than 60%.When the environment conditions change,heavy metals in the leachate can be easily released to the overlying water column and cause high ecological risks.The results of correlation and principal component analyses reveal that heavy metals in the leachate are incorporated into the sediments from aqueous solution,by processes such as adsorption onto Fe-Mn oxides and organic complexation,predominantly controlled by emissions from industrial and agricultural activities.According to the data of enrichment factor（EF）and potential ecological risk index,Cd is the most enriched element in the Jiaojiang sediments,especially in the upstream region,the Yongan River,where Cd is significantly enriched with high ecological risk,while Zn,Pb,Cr,Cu all display mild to moderate increase.The accumulation of heavy metals in the rivers in southeastern China and their ecological risks deserve further investigation.

关 键 词：河流沉积物 重金属 相态分析 人类活动 富集 

分 类 号：X52[环境科学与工程—环境工程] X824