南京市紫金山土壤中6种重金属的污染特征和污染水平评价

摘要

In order to explore influence of human activities on soil of Purple Mountain Forest Park in Nanjing,pollution characteristics of 6 heavy metals (Cu,Zn,Pb,Cr,Ni,Mn) were studied.Moreover,pollution level evaluation was conducted using single factor index method and Nemero comprehensive index method.Results showed that Cu mass concentrations ranged from 4.21 to 249.75 mg/kg with an average of 64.08 mg/kg,Zn ranged from 155.26 to 418.75 mg/kg with an average of 212.34 mg/kg,Pb ranged from 112.19 to 608.91 mg/kg with an average of 319.57 mg/kg,Cr ranged from 29.54 to 201.25 mg/kg with an average of 127.36 mg/kg,Ni ranged from 46.64 to 142.48 mg/kg with an average of 76.16 mg/kg,and Mn ranged from 182.59 to 1 634.48 mg/kg with an average of 1 008.93 mg/kg.In general,heavy metal mass concentrations of upper samples (0-20 cm) were higher than that of lower ones (20-40 cm),and that of high altitude lower than that of low altitude.Nemero comprehensive index implied that all samples were at heavy pollution level.Pb were found to be the main contributor through single factor index analysis.%为探究人类活动对南京市紫金山国家森林公园土壤重金属污染的影响,研究了紫金山土壤中6种重金属(Cu、Zn、Pb、Cr、Ni、Mn)的污染特征,并采用单因子指数法和内梅罗综合指数法进行了污染水平评价.结果表明:Cu的质量浓度范围为4.21～249.75 mg/kg,平均值为64.08 mg/kg;Zn的质量浓度范围为155.26～418.75 mg/kg,平均值为212.34 mg/kg;Pb的质量浓度范围为112.19～608.91 mg/kg,平均值为319.57 mg/kg;Cr的质量浓度范围为29.54～201.25mg/kg,平均值为127.36 mg/kg;Ni的质量浓度范围为46.64～142.48 mg/kg,平均值为76.16 mg/kg;Mn的质量浓度范围为182.59～1 634.48 mg/kg,平均值为1 008.93mg/kg.总体而言,上层样(0～20 cm)的重金属浓度高于下层样(20～40 cm),高海拔的重金属浓度低于低海拔的.内梅罗综合指数表明,所有采样点均处于重度污染状态.分析6种重金属的单因子指数发现,主要是因为Pb的单因子指数较大.