渤海有毒金属污染状况和研究进展

State of toxic metals in the Bohai Sea,China: A review

有毒金属(Hg、Cd、Pb、As和Cr)是环境中常见的污染物,对生态环境和人类健康产生了重要的影响。本文综述了有毒金属在渤海及其沿岸入海河流中的水体、沉积物、大气沉降和生物体中的污染特征、空间分布及可能来源。渤海海水未明显受到有毒金属的污染,除Hg外,其含量的空间分布特点为近岸高,离岸和中部海区较低。沿岸河流和河口的沉积物中存在有毒金属(Hg、Cd、Pb和Cr)污染,但As污染不明显。渤海湾、锦州湾和莱州湾等的沉积物中Pb和Cd污染明显高于其它元素,这可能与有毒金属的沉积过程和迁移转化特点有关。沉积物中有毒金属含量的分布大体上呈现北高南低,河口处较高,并在渤海湾中部泥质中富集,而渤海中部海区较低。Cd具有较高的生物有效性,但其在沉积物中总量较低,尚不构成环境风险。渤海由人类活动引起的有毒金属累积明显,陆源工业废水排放是有毒金属的主要来源,入海径流和大气沉降输入也是渤海有毒金属的可能来源。

Toxic metals（ Hg,Cd,Pb,As and Cr） are considered as important pollutants and there is extensive literature concerning their impact on the environment and human health. In this review the recent studies on pollution state, spatial distribution and possible sources of toxic metals in water,sediments,atmospheric deposition and organisms in the Bohai Sea and its major coastal rivers will be presented. Seawater in the Bohai Sea has not been contaminated with toxic metals significantly. With the exception of Hg,the contents of toxic metals are higher inshore than offshore and the central area of the Bohai Sea. Sediments in the coastal rivers and estuaries are contaminated with Hg,Cd,Pb and Cr,but not heavily polluted with As. Pollution levels of Pb and Cd in the sediments are significantly higher than those of other toxic metals in Bohai,Jinzhou and Laizhou bays,which may be due to their deposition,migration and transformation. The spatial distribution of toxic metals in the sediments indicates that the contents are higher in the north than the south,their contents in the sediments in the esaturies and central area of Bohai Bay were high,but low in the central area of the Bohai Sea. A high mobility of Cd is observed,but it do not cause a bad effect on the environment owing to its low total concentration in the sediments. Anthropogenic influence on the accumulation of toxic metals in the Bohai Sea sediments is obvious. This review indicates that toxic metals from industrial wastewater are major sources,and river runoff and atmospheric deposition are also possible sources in Bohai Sea.