黄海表层沉积物中重金属的分布特征与生态风险评价

Distribution Patterns and Evaluation on Potential Ecological Risk of Heavy Metals in Surface Sediments of the Yellow Sea

[目的]研究黄海表层沉积物中重金属的分布特征,评价其生态风险。[方法]对黄海海域表层沉积物中重金属(Cu、Mn、Pb、Zn、Cr、Fe、Hg和Cd)的含量分布和富集状况进行了调查,分析了重金属之间以及重金属与有机碳(TOC)含量之间的相关性,并采用Hakan-son的潜在生态危害指数法评价了该海域重金属污染的程度及其潜在的生态危害。[结果]在南黄海中部和威海以北的北黄海西部海域表层沉积物中Cu、Pb、Zn、Cr、Fe和Hg的含量偏高,海州湾和北黄海北部含量偏低,Mn、Cd的分布较不均匀,离散程度较大;黄海表层沉积物中各项重金属含量均存在正相关性,Pb与Zn、Zn与Cr、Pb与Cr的相关系数分别达到0.97、0.96和0.94。Cd和Cu呈显著相关,但Cd与其他重金属无显著相关关系,重金属与TOC之间也存在正相关。潜在生态危害评价结果表明,黄海表层沉积物只有部分站点处于生态危害的中等级别,大多站点生态危害轻微,各个重金属元素的潜在生态风险程度由强到弱依次为Cd>Hg>Cu>Pb>Cr>Zn,对黄海表层沉积物具有潜在影响的重金属主要是Cd;底质环境质量评价显示,南黄海中部的泥质沉积区域环境质量较差,应予以重视。[结论]该研究为黄海环境保护和生态系统的可持续发展提供了理论依据。

[Objective] The aim was to study distribution patterns of heavy metals in surface sediments of the Yellow Sea and evaluate its potential ecological risk.[Method] Content distribution and enrichment situation of heavy metals including Cu,Mn,Pb,Zn,Cr,Fe,Hg and Cd in surface sediments of the Yellow Sea were analyzed.The correlativity between every two heavy metals as well as between the heavy metal and organic matter were analyzed.Simultaneously,pollution levels of these heavy metals including Cu,Pb,Zn,Cr,Hg and Cd and their potential ecological risks were evaluated by the index method on potential ecological risk.[Result] The contents of Cu,Pb,Zn,Cr,Fe and Hg in surface sediments appeared higher in the mid of South Yellow Sea and west of North Yellow Sea but lower at the Haizhou bay and north of North Yellow Sea,and Mn,Cd distributed unevenly.Positive correlation was found between the concentrations of every two metals;the correlation coefficient between Pb and Zn,Zn and Cr was 0.97 and 0.96,respectively,while for Pb and Cr the coefficient was 0.94.The correlation coefficients between Cd and the other metals（except Cu） was very low,showing no remarkable correlation relationship.The potential ecological evaluation proves that surface sediment in the major sites were in the slight ecological risk condition,but that of some sites were in moderate ecological risk condition.The pollution degree of these heavy metal was in order of CdHgCuPbCrZn,with Cd being the potential impact element for the ecological environment of the Yellow Sea.From the results of cluster analysis,the mid of South Yellow Sea had lower sediment environmental quality,therefore much attention should be paid to these areas.[Conclusion] The research provides theoretical basis for environmental protection of the Yellow Sea and the sustainable development of ecological system.