采用电感耦合等离子体发射光谱仪(ICP-AES)测定了南京玄武湖3个不同湖区沉积物中的7种重金属元素(Cd、Cr、Cu、Mn、Ni、Pb、Zn)的浓度,对重金属元素的垂向分布规律进行了研究,并应用地质累积指数法对重金属的污染程度进行了评价。结果表明:不同湖区沉积物(0~20 cm)样品中重金属含量顺序为北湖〉东南湖〉西南湖,沉积物中7种重金属元素浓度由高到低的排列顺序为Mn〉Zn〉Pb〉Ni〉Cr〉Cu〉Cd,随着沉积物深度的增加,重金属浓度呈减小趋势;重金属Cd、Pb、Zn的平均浓度分别在1.1~1.7、33~38和150~400mg/kg的范围内波动,均大于南京土壤环境中的背景值;地累积指数法的评价结果表明,北湖的重金属污染程度最严重,产生污染的主要重金属元素为Cd和Zn,污染分级分别是中度和轻度偏中度污染。
Concentrations of 7 heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn in the sediments of three different areas of Xuanwu Lake, Nanjing were investigated with inductively coupled plasma-atomic emission spectrometry (ICP- AES). Vertical distribution of the metals in the Lake sediment was studied and the pollution status was assessed using geo- accumulation index. Results showed that the concentrations of heavy metal in sediments samples (0-20 cm) of different lake zones followed the order from high to low as north lake zone, southeast lake zone, southwest lake zone. And the concentrations of 7 heavy metals in the sediment samples followed the order of Mn, Zn, Pb, Ni, Cr, Cu, Cd. Metal concentrations decreased with increasing depth in the sediments. Average concentrations of Cd. Pb and Zn were within 1.1-1.7,33-38 and 150-400 mg/kg which were all larger than the soil background values of Nanjing. Assessment results based on geo-accumulation index showed that the pollution status of the north lake zone is the most serious among the three lake zones, dominated with Cd and Zn whose pollution levels were moderate and mild to moderate respectively.