东营市北部海域沉积物中重金属的分布、来源及生态风险评价

2016年5月在东营市北部海域采集沉积物样品并测定7种重金属含量,分析其空间分布特征和来源,并采用沉积物质量基准(SQGs)和潜在生态风险指数(PERI)两种方法评价其生态风险.结果表明,该海域沉积物中Hg、As、Pb、Cd、Cr、Cu、Zn含量分别为0.005~0.092、3.44~10.41、6.59~19.00、0.50~1.10、32.42~60.25、1.72~23.78、31.13~69.96mg·kg~(-1);重金属含量最高值、次高值多出现在靠近挑河入海口且有机质、粉砂和黏土含量较高的S10站位.沉积物中的As、Pb主要来自岩石风化,其它金属则来自地表径流输送的陆源污染物.某些站位的As、Cd、Cr、Cu含量超出临界效应浓度(TEL),会偶尔产生不利生物毒性效应.除S10、S3、S9站位(属于高生态风险)外,该海域沉积物中的重金属处于中等生态风险,且风险主要来自Cd、Hg.为降低该海域的重金属生态风险水平,必须采取措施控制挑河等河流的重金属入海通量.

Spatial Distribution, Source and Ecological Risk Assessment of Heavy Metals in the Coastal Sediments of Northern Dongying City

Concentrations of seven heavy metals in the coastal sediments of the northern Dongying City were measured. The spatial distribution and sources of heavy metals were discussed and the ecological risk was assessed using sediment quality guidelines (SQGs) and the potential ecological risk index (PERI). The concentration ranges of Hg, As, Pb, Cd, Cr, Cu, and Zn were calculated as 0.005-0.092, 3.44-10.41, 6.59-19.00, 0.50-1.10, 32.42-60.25, 1.72-23.78, and 31.13-69.96 mg·kg^-1, respectively. Higher metal concentrations were observed at site S10, which was close to the mouth of Tiaohe River and contained plenty of organic matter, silt, and clay. Principal component analysis (PCA) indicated that As and Pb in the sediments were derived from natural weathering processes, while other metals were mainly attributed to anthropogenic sources, i.e., land-sourced pollutants transported by runoff. Concentrations of As, Cd, Cr, and Cu at some sampling sites exceeded the threshold effect level (TEL) stated in the SQGs implying occasional harmful effects on biological life. PERI showed that the sediments in this area generally had a medium risk, except sites S10, S3, and S9 posing a considerable risk, and that Cd and Hg were the major contributors to the ecological risk. It is necessary to take effective measures to control heavy metal fluxes from rivers around this area and to reduce the risk.