珠江口表层沉积物重金属潜在生态风险及生物富集评价

Assessment of the Potential Ecological Risk of Heavy Metals in the Surface Sediments and Biological Accumulation in Pearl River Estuary

基于2019年珠江口海域表层沉积物Hg、As、Cu、Pb、Cd、Zn、Cr的分析结果对沉积物重金属污染现状及潜在生态风险进行评价,结合总有机碳TOC、粒度等探讨海域重金属的污染特征及来源,并评估各项重金属元素在底栖生物体内的富集程度。结果表明,所有站点表层沉积物中Hg和Cr含量均符合一类海洋沉积物质量标准,As、Cd、Pb、Cu和Zn满足二类以上标准。Hg和Cd为主要生态风险贡献因子,均有部分站点属较高和中等潜在生态风险范畴,综合潜在生态风险指数(RI)均值属中等潜在生态风险范畴,近岸海域尤其北部、西部RI值较高。7项重金属含量两两间呈极显著正相关,显示重金属污染具有相近来源,且重金属含量均与TOC含量呈极显著正相关,而与粒度无明显相关性。7项重金属元素在甲壳类和鱼类体内均没有富集,Cd在双壳类体内出现较强富集。

The status and potential ecological risks of heavy metal pollution in surface sediments were evaluated based on the analysis results of Hg,As,Cu,Pb,Cd,Zn,Cr from Pearl River estuary in 2019.The pollution sources of heavy metals were analyzed combined with TOC and granularity,also the accumulation of heavy metal in benthos.The results showed that the contents of Hg and Cr in the surface sediments of all sites met the quality standards of the first class marine sediments.Hg and Cd were the main ecological risk contribution factors that some positions in the category of high and medium potential ecological risk.The average value of the comprehensive potential ecological risk index(RI)was in the category of medium potential ecological risk,especially in the north and west of offshore area.7 heavy metal contents showed a significant positive correlation between each other,indicating the similar sources,and the heavy metal contents were positively correlated with TOC,but had no significant correlation with granularity.Heavy metal elements were not accumulated in Arthropoda and Chordata,but Cd was accumulated in Bilalvia significantly.