摘要
为探究长江口东南支海域表层沉积物重金属形态分布特征及污染状况,本研究于2019年12月在长江口邻近海域采集了18份表层沉积物样品,使用微波消解法以及改进后的沉积物重金属形态分析的连续提取法分别分析了沉积物中7种重金属(Cu、Pb、Cd、Cr、Zn、As、Ni)的总量和各形态含量,结合沉积物质量基准(SQG)、风险商(HQ)等方法初步探讨了长江口邻近海域表层沉积物中重金属的赋存形态特征,并评估了其生态风险。结果显示,从近岸到近海,重金属含量梯度逐渐减小,除Cd、Cr属于Ⅱ级标准,其余重金属平均含量均达到海洋沉积物质量Ⅰ级标准。长江口邻近海域沉积物呈中性-弱碱性,属还原环境;Zn、Pb、Cd以次生相为主要赋存形态,对环境条件变化较为敏感,其中Cd次生相的质量分数最高(74.2%),且以可还原态为主要赋存形态,Cu、Cr、As、Ni以原生相为主要赋存形态,性状相对稳定。生态风险评估结果表明,长江口邻近海域表层沉积物重金属的组合生物效应对水生生物产生危害的概率较低。As与Cd元素的生态风险较高,尤其是Cd,易被生物利用,对环境危害性更强,需要引起重视。
In order to explore the characteristics of occurrence and status of pollution of heavy metals in surface sediments in the southeastern branch of the Yangtze River estuary, 18 surface sediment samples were collected in Yangtze River estuary in December 2019. The total content and the levels of each morphology of the seven sediment heavy metals(Cu, Pb, Cd, Cr, Zn, As, Ni) were analyzed based on methods of microwave digestion and the improved continuous extraction. Moreover, the ecological risks of heavy metals were evaluated by deposition methods such as sediment quality guideline(SQG) and hazard quotients(HQ). The results showed that the concentrations of heavy metals gradually decreased from nearshore to offshore. Most of heavy metals all reached China’s marine sediment quality Class I standard, except for Cd and Cr(Class II standard). The sediments in the researched area were neutral-weakly alkaline and presented a reducing environment. Zn, Pb,and Cd mainly presented in secondary facies, which are more sensitive to the environmental conditions. Among them, the Cd secondary facies had the highest ratio(74.2%), and the reducible state was the main occurrence form. In addition, the stable primary phase of Cu, Cr, As, Ni was the main occurrence form. Ecological risk assessment results showed that it was found that the combined biological effects of heavy metals in the surface sediments of the Yangtze River estuary had low probability of affecting aquatic organisms. As and Cd had a higher risk of ecological hazards than other metals, especially Cd as it was easy bio-utilization and threatened to the environment, therefore, we should pay attention to the element Cd.
作者
符运拓
杨红
王春峰
Yun-tuo FU;Hong YANG;Chun-feng WANG(College of Marine Ecology and Environment,Shanghai Ocean University,Shanghai 201306,China)
出处
《海洋环境科学》
CAS
CSCD
北大核心
2022年第4期534-542,553,共10页
Marine Environmental Science
基金
上海市长江口水域重金属监测项目(D-8006-20-0029)
上海市滨海典型海域生态环境质量提升技术研究项目(沪海科2015-02)。
关键词
长江口
沉积物重金属
形态分析
风险评价
Yangtze River Estuary
heavy metals in sediments
speciation analysis
risk evaluation