2016年惠州海域表层沉积物重金属污染分析

Analysis of Heavy Metal Pollutionsin Surface Sediments in Huizhou Basin in 2016

2016年10月在惠州海域采集表层沉积物样品,分析了沉积物中Cu、Zn、Pb、Cd、Cr、Hg、As等7种重金属元素的含量,采用地积累指数法、沉积物质量基准法和潜在生态风险指数法进行重金属污染现状和生态风险评价,并与2016年8月份的沉积物数据相比较。结果表明:(1)惠州海洋沉积物7种重金属含量平均值符合沉积物第一类标准,重金属的富集系数由大到小依次为Cd>Zn>Cu>Pb>As>Cr>Hg。与2016年8月相比,沉积物总体质量升高,Cd的超标率降低,而Cu、Pb、Hg含量有所升高。(2)Pearson相关分析显示,沉积物中重金属元素具有同源性,有机碳、硫化物和沉积物粒径是决定沉积物重金属含量的重要因素。(3)地积累指数法评价结果显示,重金属元素的污染程度为Cd>Zn>Pb>Cu>As>Cr>Hg。7种重金属元素的污染程度较2016年8月有所下降。(4)惠州海洋沉积物7种重金属元素含量皆未超过ERM值,不会产生生物负作用。m-ERM-Q平均值为0.11,反映有21%的毒害可能性。(5)潜在生态风险指数法评价结果显示,潜在生态风险系数Eir由高到低依次为Cd>As>Cu>Pb>Hg>Zn>Cr,Cd具有很强生态风险;沉积物重金属RI平均值为249.03,处于中等生态风险。沉积物Cd的生态风险等级较2016年8月降低,RI平均值也降低。

Concentrations of Cu,Zn,Pb,Cd,Cr,Hgand As in surface sediments in October 2016were analyzedand the potentialecological risks of each heavy metals were evaluated with the contrast of results during August 2016.The results are showedas follows.(1)The mean contents of heavy metals indicated the 1st order quality of marine sediments.The enrichment factors followed the order:Cd>Zn>Cu>Pb>As>Cr>Hg.In contrast with the results inAugust 2016,the sediment quality increased, while the exceeding rate of Cd declined with the increasing of Cu,Pb and Hg contents.(2)Pearson correlations suggest that the source of heavy metals in marine sediments in Huizhou were similar.Or- ganic carbon,sulfide and grain sizes affected the contents of heavy metals greatly.(3)The pollution extent of heavy metals in marinesediments by geo-accumulation index (Igeo)followed the order:Cd>Zn>Pb>Cu>As>Cr>Hg.It declined in contrast to that in August 2016.(4)None of themeasured concentrationof the sampling sites exceeded the ERM reference values,and their presence may not cause adverse biological effects.The mean value of m-ERM-Q was 0.11,indicating a 21% probability of negative biologicaltoxicity.(5)The potential ecological risk of heavy metalsin surface sediments by the potential ecological risk index (Er^i)were in the following order:Cd>As>Cu>Pb>Hg >Zn>Cr. The mean potential ecological risk indexes (RI)was 249.03,suggesting the moderately potential ecological risk.The potential ecological risk of Cd and the mean value of RIdeclined in contrast to those in August 2016.