安海湾表层沉积物重金属含量分布特征

Distribution characteristics of heavy metals concentration in surface sediments of Anhai Bay

根据2014年8月福建安海湾9个站位表层沉积物中6种重金属的含量调查,探讨它们的分布趋势,对重金属含量进行单因子指数评价,同时对该海域污染程度进行潜在生态危害评价.结果表明,该海域表层沉积物中重金属Cu含量范围11.4~123.0μg/g,平均值55.3μg/g;Pb含量范围18.4~39.8μg/g,平均值34.7μg/g;Zn含量范围31.8~173.0μg/g,平均值100.0μg/g;Cd含量范围0.06~0.36μg/g,平均值0.14μg/g;As含量范围4.01~9.60μg/g,平均值6.67μg/g;Hg含量范围0.005~0.115μg/g,平均值0.036μg/g.含量分布呈现从湾顶向湾内及湾口逐渐降低,以AH1站和AH5站为最高值;Pb、Cd、As、Hg含量均符合海洋沉积物质量标准的第一类要求,Cu、Zn含量符合沉积物质量标准第一类要求的站位各占了44.4%和77.8%,各元素之间呈明显正相关.单项潜在生态危害系数Cd>Hg>As>Cu>Pb>Zn,潜在生态危害指数评价AH1站属于强生态危害,AH5站为中等生态危害,余下各站点为轻微生态危害,重金属Cd的潜在生态危害最大.AH1站靠近湾顶陆源排污口,AH5站靠近东石陆源排污口,污染强度较其他站位大很多.安海湾表层沉积环境已受到不同程度的重金属污染,近海工业活动和陆源污染物排放是安海湾重金属污染的主要来源.因而,严格控制入海河流和近海经济活动的重金属污染排放,对保障安海湾沉积物的生态环境至关重要.

Based on the investigation on 6 heavy metals（Cu、 Pb、 Zn、 Cd、 As、 Hg） at 9 sites in Anhai Bay in August 2014, the distribution of heavy metals were analyzed, heavy metals content was evaluated with single factor index method,and pollution level of heavy metal was evaluated with the potential ecological risk index. Results showed that copper （ Cu ） content was measured between 11.4 and 123.0 μg/g with average 55. 3 μg/g, lead （ Pb ） content between 18. 4 and 39. 8 μg/g with average 34. 7 μg/g,zinc （Zn） content between 31.8 and 173.0 μg/g with average 100.0 μg/g,cadmium （Cd） content between 0. 06 and 0. 36 μg/g with average 0. 14 μg/g, arsenic （As） content between 4. 01 and 9. 60 μg/g with average 6. 67 μg/g, mercury （Hg） content between 0.005 and 0. 115 μg/g with average 0.036 μg/g. The content of heavy metals decreased gradually from the top of the bay to inner bay and the bay mouth with the highest value at site AH1 and AH5. The concentrations of Pb, Cd, As, Hg were fit in class 1 of the National Marine Sediment Standard. The fitting rate of Cu and Zn to the class 1 is in 44. 4% and 77. 8% , respectively. Positive correlations are evident among the metals. Individual potential Ecological risk coef-ficient of heavy metals were in sequences of Cd 〉 Hg 〉 As 〉 Cu 〉 Pb 〉 Zn. The potential ecological risk index （ RI） indicates that site AH1 was in the strong potential ecological risk, site AH5 was moderately polluted and the remaining sites were in the lightly potential ecological risk. Among them heavy mental Cd has the greatest potential ecological risk. It suggested that the pollution of heavy metals in site AH1 and AH5 is much higher than that in other sites and might be due to many terrigenous pollutants in the top of the bay and the Dongshi outlet. The sediment environment of Anhai Bay has suffered heavy mental pollution in different degree, which indicated that the pollution of heavy metals was probably caused by industrial activities and land source pollution in Anhai Bay. Therefore, it is of great importance to control the discharge of the heavy metal through river inflow and economic activity to protect the ecological environment of the sediments in Anhai Bay.