烟台开发区近海表层沉积物重金属的分布特征与风险评价

Distribution and risk assessment on heavy metals in surface sediments from offshore area of Yantai economic development zone

对烟台开发区近海表层沉积物6种重金属及有机碳进行了测定,探讨了重金属含量、分布特征与有机碳间的相关关系,并采用地累积指数法和潜在生态风险指数法进行了污染及风险分析。结果显示:研究区域重金属含量均值低于国家沉积物质量Ⅰ类标准上限值。Cu、Zn、As含量呈现由西至东降低、套子湾内由北向南增大的趋势;除调查区域西侧外,Pb、Cd在山后附近海域存在另一高值区,而Hg高值则主要集中在调查区域西侧。Pearson分析表明,Cu、Hg、Zn、As之间及与有机碳含量间存在显著正相关性。Igeo评价显示,Cd以轻度污染为主,而Cif计算表明Cd属于中等污染;Cd显示调查区域基本属于低污染,西侧3个站位达到中等污染程度。风险评价表明,Cd为最主要的风险因子,Hg也存在一定风险。调查区域总体属于低风险,部分站位达到中等风险,主要受Cd和Hg污染所致。

The concentrations of 6 heavy metals and organic carbon contents were determined in surface sediments collected from offshore area of Yantai economic development zone,and their correlation was investigated to assess the potential ecological risk of this region.It was found that the average contents of all 6 heavy metals were lower than the upper limit of Ⅰ class criteria specified in the Marine Sediment Quality Standard(GB18668-2002).The spatial distributions of Cu、Zn、As decreased from west to east,and increased from north to south in Taozi Bay.The high contents of Pb,Cd were distributed at stations around Shanhou area and the west side of the area investigated,while high concentration of Hg located mainly at the west side.Pearson analysis revealed that Cu,Hg,Zn and As concentrations showed strongly positive correlation between each other and with organic carbon contents.Geoaccumulation index(Igeo) assessment indicated slight pollution of Cd in the area surveyed,while moderate pollution was suggested by using C if analysis.Furthermore,3 stations in the west side of investigation area had reached the moderate pollution level according to Cd assessment.Risk index evaluation suggested that Cd was the main risk factor in this region.On the whole,the monitoring region was in low-risk condition with several stations at the moderate risk level due to the contamination of Cd and Hg.