江苏中部潮间带表层沉积物重金属分布、来源及污染评价

Heavy metal contamination in surface sediments of intertidal zone in central Jiangsu Province:distribution,source,and assessment

基于2015年江苏中部潮间带89个站位表层沉积物的测试分析结果和以往资料,探讨了Cu、Pb、Zn、Cr、Cd、As和Hg 7种重金属元素的含量、空间分布特征和相关性,并采用沉积物质量基准法、地累积指数法和富集系数对该区重金属状况进行了系统评价。结果表明,表层沉积物中重金属元素含量相差较大,平均含量由高至低依次为Cr>Zn>Cu>Pb>As>Cd>Hg,空间分布不均匀,高值区呈点状或片状分布。沉积物质量符合中国海洋沉积物质量第一类标准,所有站位的重金属含量均低于可能效应水平(PEL),综合潜在生态风险为低风险。元素相关性分析、地累积指数、富集系数和R型因子分析结果表明:Cu、Pb和Zn元素主要来自于地壳物质或自然风化作用,未污染、未富集;Cr元素含量受自然和人类活动共同作用的影响,部分站位轻度污染和轻度富集;Cd、As和Hg元素含量受人类活动影响较大,较为富集,污染程度较重。

Surface sediment samples were collected at 89 stations from intertidal zone in central Jiangsu Province in 2015.The concentrations,spatial distribution patterns,and interrelations of seven heavy metals(Cu,Pb,Zn,Cr,Cd and Hg)were studied and compared with previous investigations.The pollution status was evaluated systematically with China’s national sediment quality guidelines,geoaccumulation index,and enrichment factor.Results show that the concentrations of heavy metals in surface sediment varies greatly,and the average concentration followed the descending order of:Cr>Zn>Cu>Pb>As>Cd>Hg.The spatial distribution was uneven.Highvalue areas were spot-like or in patch.The heavy metal concentrations at all stations were below the possible effect level,and the overall potential ecological risk was low.The Pearson correlation coefficients,geoaccumulation indexes,enrichment factors,and R-type factor analysis show that heavy metals Cu,Pb and Zn were not polluted or enriched,and they were mainly from crustal materials or natural weathering.Cr was slightly polluted and enriched,which were jointly affected by natural weathering and human activities.Cd,As,and Hg were enriched and heavily polluted,which were mainly derived from anthropogenic sources.