浙北海域表层沉积物中重金属的含量特征、来源和污染评价

为了解浙北海域表层沉积物中重金属的含量和分布特征，本研究以浙北海域64个站位的沉积物为研究对象，检测了Cu、Zn、Cr、Ni、Pb、As、Cd和Hg共8种重金属的含量，并分析了其主要来源和生态风险。结果表明，Cu、Zn、Cr、Ni、Pb、As和Hg（除了s112）的含量均未超过一类海洋沉积物质量标准，68.8%的已检出站位Cd的含量达到三类质量标准。Cu、Zn、Ni和As 4种元素呈现出由近岸向外海浓度逐渐降低的趋势（p < 0.01）。溯源分析表明，Cu、Zn、Cr、Ni和As主要来自陆源的工农业和生活污水，Pb和Cd主要来自船舶废气、海水养殖和工业污染。地积累指数表明8种重金属的污染程度由高到低依次为:Cd > Ni > Cu > Hg > Cr > Zn > Pb > As，只有Cd在所有检出站位中最低浓度也呈现出偏中度污染。潜在生态风险系数评价表明，Hg在3.1%站位存在强生态风险，Cd在所有检出站位中最低浓度也呈现出强生态风险。综合评价8种重金属，发现浙北海域21.87%的采样点存在强生态风险，其中Cd对潜在生态风险指数（RI）的贡献达到84.71%。

Contents,sources and pollution assessment of heavy metals in coastal sediments of northern Zhejiang

The concentrations of 8 heavy metals (Cu, Zn, Cr, Pb, Ni, As, Cd and Hg) were analyzed and the potential ecological risks were evaluated to investigate polluting characteristics of heavy metals in coastal sediments of northern Zhejiang. The results demonstrated that the total concentrations of Cu, Zn, Cr, Ni, Pb, As and Hg(except s112)did not exceed class 1 of the marine sediment quality, Cd was at class 3 of the marine sediment quality in 68.8% of the detected sites. The concetrations of Cu, Zn, Ni and As manifested a decreasing trend from nearshore to offshore (p < 0.01). The main sources of Cu, Zn, Cr, Ni, and As were probably industry, agriculture and domestic wastewater, and Pb and Cd mainly came from traffic, mariculture and industrial pollution. The pollution ranks of heavy metals in sediments by geo-accumulation index (I_geo) followed the order:Cd > Ni > Cu > Hg > Cr > Zn > Pb > As, and only Cd was found to be rank 2(Moderately polluted) or above in all detected sites. The results of the potential ecological risk factors (E_ri) illustrated that Hg was disastrous risk at 3.1% of sampling sites, Cd was at rank 3(considerable risk) even higher in all detected stations. The ratio of considerable risk was 21.87% in coastal sediments of northern Zhejiang, the most of potential ecological risk index (RI) were contributed by Cd, accounting for 84.71%.