胶州湾水环境重金属立体分布、污染及风险

On Distribution and Pollution of Heavy Metals in Water Environment of Jiaozhou Bay in Yellow Sea

为探讨胶州湾水环境中重金属的立体空间分布、污染及风险,分别采集深度为0~10m（表层）,10~20m（中层）和20~30m（底层）的海水与海底表层（0~10cm）沉积物样本,测定8种重金属（As,Cd,Cr,Hg,Zn,Pb,Cu和Ni）在水体中的质量浓度（mg/L）和沉积物中的质量分数（mg/kg）,基于国家海水水质标准和水质质量指数法、海洋沉积物质量标准和Hakanson潜在生态危害指数法评价了海水和沉积物中重金属的立体分布、污染及其潜在生态风险.结果表明：胶州湾海水重金属质量浓度除Cu,Hg,Ni和Pb外,均未超出IV类标准;相对污染指数值由大到小依次为Cu,Pb,Hg,Ni,Cd,Cr,Zn,As,其中Cu,Pb,Hg,Ni和Cd达到严重污染水平,综合污染指数测算表明胶州湾海水重金属污染严重.就胶州湾海水重金属的平面分布而言,其高值区出现在湾东和西南区,其中Hg高值区沿胶州湾大桥分布.就胶州湾海水重金属的垂直方分布而言,0~10m的表层海水和20~30m的底层海水中重金属质量浓度均高于10~20m的中层海水.除Cr外,沉积物中其他重金属质量分数均高于海洋沉积物的I级质量标准,潜在生态风险指数由大到小依次为Hg,As,Ni,Cd,Pb,Cr,Cu,Zn,并呈现出东高西低、沿污染源分布的特点.

In order to investigate the vertical distribution and pollution in water environment of Jiaozhou Bay,the representative samples of seawater（0-30m）and sediments（0-10cm）in different depths and area have been collected from Jiaozhou Bay,and the concentration of focused heavy metals（As,Cd,Cr,Hg,Zn,Pb,Cu and Ni）been determined by ICP-MS and Atomic Fluorescence system,national seawater quality standards and comprehensive pollution index（CPI）,national sediments quality standards and potential ecological risk index（RI）been applied to estimate their vertical pollution degree and potential risk.The results of seawater show that concentration of heavy metals in seawater met IV categories of national seawater quality standards,except Cu,Hg,Ni and Pb.values of seawater from large to small are：Cu〉Pb〉Hg〉Ni〉Cd〉Cr〉Zn〉As,which indicates that seawater is polluted heavily by Cu,Pb,Hg,Ni and Cd.The result of CPI shows the heavy pollution of seawater.In horizontal direction,the highest values of metals have distributed alone east and southwest coast.And the highest value of Hg has been distributed alone Jiaozhou cross-ocean bridge.In vertical direction,concentration of metals in surface water（0-10m）and bottom（21-30m）water is higher than intermediate（11-20）.In sediments,almost all values of metals twice the I national sediments quality standards except Cr,and Hg is the highest value.RI value of Jiaozhou Bay is placed from large to small：Hg〉As〉Ni〉Cd〉Pb〉Cr〉Cu〉Zn.Moreover,all metals have been distributed alone polluted sources,and the concentration has reduced from east to west.