泉州湾洛阳江潮间带表层沉积物重金属污染评价

EVALUATION OF POLLUTION OF HEAVY METALS IN LUOYANGJIANG INTER-TIDAL SEDIMENTS,QUANZHOU BAY

泉州湾洛阳江潮间带表层沉积物中12种重金属元素含量分析表明,Co,Fe含量与海岸带土壤背景值较接近且变异系数很小,其含量主要来源于沉积物的本底值,受到人类活动的影响较小,而其他重金属与海岸带土壤背景值相差甚大(达几倍至几十倍)且变异系数较大,说明其已受到人类活动的影响较大,受到一定程度的污染。基于沉积物中重金属总量,用5种评价方法对洛阳江潮间带表层沉积物中重金属污染进行评价。以海洋沉积物质量标准(GB18668-2002)进行评价,洛阳江潮间带表层沉积物中各重金属平均含量均为二类沉积物质量标准,不能满足该区域应执行的一类标准。据地累积指数法,表层沉积物中V,Co,Hg,Fe为无污染水平,Cr,Mn,Zn,Pb为无-中等污染水平,Cu为中等污染水平,而Cd为强污染水平。以潜在生态风险指数法评价,研究区内各元素的平均潜在生态危害系数(Eri)顺序为:Cd>Hg>Cu>Cr>Ni>Zn>Pb>Co>Mn>V>Ti。沉积物中重金属综合潜在生态风险指数(RI)表明,研究区域总体上处于生态风险极高水平,Cd,Hg,Cu为重要污染因子。以生物效应浓度法评价,Cr,Ni,Cu,Zn,Cd,Pb的区域总平均含量均在其各自的ER-L与ER-M之间,说明洛阳江潮间带表层沉积物中以上元素对生物的负面效应中等。以综合响应因子法评价,从研究区总平均来看,沉积物重金属污染指示元素及其污染贡献大小顺序为:Cd>Cu>Ni>Zn>Mn,大多站位重金属污染严重。洛阳江潮间带表层沉积物属中度-重度污染水平。

In this paper,12 kinds of heavy metals compositions of the 17 surface sediment samples in the inter-tidal belt of Luoyangjiang were analyzed.The average contents of Pb,Cr,Cu,Zn,Cd and Mn in the surface sediments were higher than those in most of other bays and estuaries home and overseas,and were higher than the background values of Fujian coastal soil.Cd is the most contamination heavy metal in all sampling stations compared to Cu,Pb,Zn,Cr,Hg and Ni.Contents of Ti,V,Co and Ni varied little among different sites,while the contents of Cu,Cd and Zn have great differences in each site.Based on the total contents of heavy metals,five assessment methods were used to evaluate the pollution degree and potential ecological risk of heavy metals in the surface sediments from intertidal zone of Luoyangjiang of Quanzhou Bay.Comparison of heavy metal contents from this study with that of Marine Sediment Quality（GB18668-2002） showed that the overall average contents of all studied heavy metals in the surface sediments from Quanzhou Bay met the secondary criteria but exceeded the recommended primary criteria.The results of geo-accumulation indices showed that Cd presented strong pollution,Cu presented moderate pollution,Cr,Mn,Zn,and Pb presented low to moderate pollution,and V,Co,Hg,Fe and Ti presented almost no pollution in most of the sites.According to the indices of potential ecological risk,the consequence of the average potential ecological risk index（Eri） for heavy metal was CdHgCuCrNiZnPbCoMnVTi.On the whole,the comprehensive potential ecological risk index（RI） of the sediments showed very high degree.According to the bio-effect concentration criterion,the average contents of Cr,Ni,Cu,Zn,Cd and Pb in the surface sediments of studied area were all between the effects range low（ER-L） and the effects range media（ER-M）,indicating moderate negative bio-effect.According to the integrated response factor,the pollution indicator elements and their pollution contribution order were as follows：CdCuNiZnMn,and most sampling sites were polluted seriously by heavy metals.