环渤海典型海湾沉积物重金属环境特征与污染评价

Distribution and Pollution Assessment of Heavy Metals in Sediments From Typical Bays in the Bohai Sea

对渤海典型海湾近年来沉积物重金属数据分析的结果表明,Hg,Cu,Cd质量浓度的平均值均超过中国海域的平均值,其中Hg和Cd超标,高值区主要分布在锦州湾、大连湾附近海域,南堡镇和曹妃甸以南海域以及东营、莱州沿岸海域。地累积指数法的评价结果显示,沉积物重金属Cd污染属于轻度污染,其余重金属未发生污染。渤海典型海湾生态危害风险最大的重金属元素为Cd,Hg次之,其余Pb,Cu,As,Cr,Zn这5种重金属均为低生态危害等级。辽东湾海域重金属生态危害风险的顺序为Cd>Hg>Pb>As>Cu>Zn>Cr;渤海湾海域重金属生态危害风险的顺序为Cd>Hg>Pb>Cu>As>Cr>Zn;莱州湾重金属生态危害风险的顺序为Cd>Hg>Pb>As>Cu>Cr>Zn。目前辽东湾沉积物重金属总潜在生态危害程度相对严重,主要分布在长兴岛、秦皇岛至锦州湾沿岸;莱州湾重金属生态危害程度一般,潍坊沿岸部分地区总潜在生态危害程度相对较高;渤海湾重金属污染生态危害程度相对较轻。

The study analyzed the contents of heavy metals in the surface sediments of the typical bays in the Bohai Sea.Compared to the average contents of the China sea,the contents of Hg,Cd,and Cu are relatively higher in the Bohai Sea.Of them,the contents of Cd and Hg reached a hazardous level,and the high-value areas were mainly distributed in the areas around the Jinzhou Bay and Dalian Bay,waters south of Nanpu Town and Caofeidian,and coastal areas of Dongying and Laizhou.The assessment by geoaccumulation index indicates that the Cd is at the slightly polluted level and Hg,Pb,As,Cu,Cr,Zn are at the unpolluted level.The assessment by the potential ecological risk index indicates that the potential ecological risk of Cd is at the highest risk level,and that of Hg is at the higher risk level,and those of Pb,As,Cu,Zn,Cr are at the low level.Heavy metals causing potential ecological risk in sequence is Cd>Hg>Pb>As>Cu>Zn>Cr in Liaodong Bay,Cd>Hg>Pb>Cu>As>Cr>Zn in Bohai Bay,and Cd>Hg>Pb>As>Cu>Cr>Zn in Laizhou Bay.Among the three studied bays,Liaodong Bay is the most seriously polluted area with the high total potential ecological risk,e.g.,some parts of the Changxing Island,and the areas from Qinhuangdao to Jinzhou Bay.The risk level of coastal areas of Weifang is higher than that of Laizhou Bay.The heavy metals in surface sediments of Bohai Bay are of light ecological risk.