崇明东滩湿地重金属分布特征及其污染状况

The distribution and pollution of heavy metals in Chongming wetland

用ICP-AES测定了2001年4月来自崇明东滩高、中、低潮滩柱状沉积物中重金属含量,并以上海土壤环境为背景值,用均方根法对长江口滨岸湿地表层沉积物重金属进行了污染综合指数计算,并对崇明东滩重金属分布和污染状况作出评价和分析.结果表明,重金属分布从低潮滩向高潮滩呈增加趋势,铁、锰、铜、锌、铬、铅、钴和镍浓度变化范围分别为2 2%～4 6%,400～1050,10～50,50～160,30～95,10～70,8～18,14～43mg/kg;高潮滩重金属在根系沉积物中(3～10cm)明显富集;在高潮滩30～70cm和中潮滩10～40cm波动较大;粒径控制柱状沉积物中重金属的分布;崇明东滩细颗粒粒径与有机碳呈显著正相关,有机质是粒径控制重金属分布的潜在因子;以上海土壤环境背景值为评价标准。

Three core sediments collected in high, medium, low tidal flat respectively in April 2001 were analyzed by ICP-AES. The results show there is a increasing trend from low to high tidal flat. The concentration of Fe,Mn,Cu,Zn,Cr,Pb,Co and Ni is in the range of 2.2%～4.6%,400～1 050,10～50,50～160,30～95,10～70,8～18,14～43 mg/kg.In the high tidal flat, distinct richness is observed in root-sediments(3～10 cm). Concentrations of heavy metals fluctuate largely in 30～70 cm in the high tidal flat and in 10～40 cm in the middle tidal flat. Grain size is the main factor of controlling the distribution of heavy metals and can be affected by 98 dam. According to the soil background values, slight pollution is observed in Chongming wetland.