小清河入海口底泥重金属空间分布特征与风险评价

Spatial Distribution Characteristics and Risk Assessment of Heavy Metals in Sediments of the Xiaoqing River Estuary

采用电感耦合等离子体发射光谱法对小清河入海口底泥中的6种重金属(As、Cd、Cu、Zn、Hg、Pb)全量进行测定,研究了其空间分布特征和影响因素,并对潜在生态风险进行评价。结果表明:除Hg含量高于国家一级背景值外,其余5种重金属含量均远低于国家一级背景值含量,整体处于清洁水平。从水平分布上看:小清河沿岸重金属含量明显高于内地,呈依次递减趋势。从纵向剖面来看:在小清河两岸,重金属Cd和Cu在剖面分布无显著性差异,其余4种重金属在不同剖面层次存在显著性差异(P≤0.05);在小清河北岸重金属Zn有向下运动的趋势。风险评价表明:小清河入海口存在重金属Hg的轻度~中等程度污染,具有强生态危害,应该加强对重金属Hg的污染监测和管控。

The contents of six heavy metals（As, Cd, Cu, Zn, Hg, and Pb） in the sediments of the Xiaoqing estuary were measured by the inductively coupled plasma emission spectroscopy. The spatial distribution characteristics of the heavy metals were studied and the potential ecological risks were evaluated by using the geo-accumulation index and potential ecological risk index methods. The results showed that the content of Hg was higher than its national background value and was lower than the second grade of the environment quality standard for soils. The contents of the other heavy metals were lower than their national background values, belonged to no pollution levels. The heavy metals contents in the shorewere significantly higher than those in the inland of the Xiaoqing River. There were no significant differences in the contents of Cd and Cu among soil profiles in the two shores of the Xiaoqing River while the significant differences（P ≤0.05） in the other four heavy metalswere found. The content of Zn showed a downward trendon the north shore of the Xiaoqing River. The correlations between heavy metalcontents and total soil carbon were weak on both sides of the Xiaoqing River. There was a strong ecological hazardfor heavy metal Hg,at mild to moderate pollution levels, in the estuary of the Xiaoqing River.Therefore, it is necessary to strengthen the monitoring and control of heavy metal Hg pollution.