深圳湾近岸海域表层沉积物中重金属污染评价

Pollution Assessment of Heavy Metals in Coastal Surface Sediments of the Shenzhen Bay

根据2006年2—3月对深圳湾表层沉积物进行的重金属调查,参照《海洋沉积物质量》(GB18668-2002)质量标准,深圳湾近岸海域表层沉积物中的重金属污染均值评价结果为:Zn为超Ⅱ类,Cr为超Ι类,Cd为近Ⅲ类,Pb属Ι类,Cu为超Ⅱ类。根据潜在生态危害评价法,5种重金属的污染程度依次为Cd>Cu>Pb>Zn=Cr,以Cd污染最为严重,其潜在生态危害指数评价已达很强水平,Cu,Pb,Cr,Zn的潜在生态危害系数评价均为轻微程度。整个研究区内的潜在生态危害指数均值为299,介于中等和强之间,水平分布规律为:深圳河河口区危害指数最低,居轻微水平;深圳湾蛇口段的危害指数居中等水平;深圳湾内侧的近岸水域测点,居于强水平。

Zn belongs to Ⅱ class, Cr over Ⅰ class, Cd near Ⅲ class, Pb Ⅰ class and Cu over Ⅱ class according to Oceanic Sediments Quality （ GB 18668-2002 ）, based on the average value of each heavy metals in the study area. The pollution assessment of each heavy metals shows Cd 〉 Cu 〉 Pb 〉 Zn = Cr, in which Shenzhen Bay is facing heavy pollution caused by Cd with much stronger impacts according to ecological risk coefficient while the other four metals belong to weak pollution level. The ecological risk index of the whole area is 299 which belongs to middle and strong level considering environmental pollution. The area with strong pollution level is the near shore area closing to the inside of the Shenzhen Bay. Shekou coast is in the middle level while the weak pollution level occurs in Shenzhen River Estuary according to the ecological risk index.