连云港近海沉积物重金属历史分布特征及其来源

分析连云港近海沉积物中的重金属含量,探讨不同功能区沉积物重金属污染演变规律、来源及其对环境造成的影响,为合理规划用海提供科学依据。选择连云港海域临洪河口河心浅滩、西连岛潮下带和灌河口北岸潮滩这3种不同的功能区为研究对象,于2014年在每个功能区各采集了1个沉积物柱状样,进行了测年和重金属Cd、Cr、Cu、Mn、Ni、Pb、Zn含量测定来分析重金属污染历史分布特征,并运用地累积指数和主成分分析说明了连云港近海不同功能区重金属污染水平和污染物来源。结果表明:1)20世纪90年代开始,各柱状样重金属污染水平出现明显的波动。2005年之后,临洪河口沉积物重金属污染水平呈现逐年下降趋势,灌河口沉积物重金属污染水平则呈波动上升趋势。2)根据地累积指数,连云港近海沉积物多数重金属污染水平处于轻度-中等污染水平,少数处于无污染状态或中等污染水平。3)重金属富集系数表明,沉积物中重金属污染受到人类活动的显著影响。相关性和主成分分析表明,临洪河口重金属来源较为多样,其次为连岛,灌河口重金属来源则较为单一。

Analysis of the Historical Distribution and Sources of Heavy Metals in Sediments from the Lianyungang Sea

In 2014, three sediment core samples were collected from different functional zones (Linhong river mouth, Lian Island Sea and Guan river mouth). The sediment dating and heavy metal contents in cores were determined to study the pollution history of heavy metals in Lianyungang Sea. The results showed that: 1) In the earlyS1990s, concentrations of heavy metals in three sediment core samples showed obvious fluctuations. After 2005, the heavy metal pollution of sediments in Linhong river mouth showed a declining trend year by year, however, concentrations of heavy metals showed an increasing tendency in sediments in Guan river mouth. 2) According to the index of geoaccumulation, most of heavy metals were in the mild-moderate pollution levels in Lianyungang offshore sediments, a few were in free or moderate pollution levels. 3) Enrichment factors of heavy metals showed that the heavy metal pollution in sediments was influenced by human activities. Correlation analysis and principal component analysis showed that the sources of heavy metals in sediment from Linhong river mouth were more diverse, followed by the Lian island, while the Guan river mouth was relatively single.