山东省部分水岸带土壤重金属含量及污染评价

为了解山东省水岸带土壤重金属的含量特征和污染状况，于2010年9月—10月采集了39个水岸带土壤样品，分析了土壤中Cr、Co、Ni、Cu、Zn、Cd、Pb和Hg的含量以及土壤的pH值、粒度和有机质，采用单因子指数法、综合指数法和潜在生态危害指数法对水岸带土壤重金属污染进行了评价，并利用相关分析和聚类分析对其来源进行了初步的解析。结果表明：水岸带土壤的pH值为5.67—8.66，主要呈碱性；有机质的平均含量为9.39 g/kg，土壤粒度主要以砂粒和粉粒为主，其平均体积百分比分别为50.33%和38.48%，平均粒径为89.69 μm；Cr、Co、Ni、Cu、Zn、Cd、Pb和Hg的平均含量为53.03 mg/kg、10.33 mg/kg、24.96 mg/kg、18.38 mg/kg、56.13 mg/kg、0.142 mg/kg、22.48 mg/kg和0.020 mg/kg。各水岸带土壤重金属的含量均符合《土壤环境质量标准》（GB15618-1995）二级标准。以山东省土壤元素背景值为评价标准，水岸带土壤重金属总体表现为轻度污染和轻微生态风险，其中Cd和Hg是主要的污染因子，其对潜在生态危害指数的平均贡献率分别为46.8% 和33.6%。洙赵新河、廖河、门楼水库和东平湖水岸带土壤重金属污染及潜在生态危害明显高于其他水源地。源解析的结果表明：水岸带土壤重金属的含量受自然源和人为源的双重影响，人为源主要包括地表径流、工业废气、垃圾和交通运输等。

Heavy metal concentrations and pollution assessment of riparian soils in Shandong Province

A total of 39 riparian soil samples were collected in 24 rivers,five reservoirs and Dongping Lake in Shandong province from September to October 2010.Concentrations of heavy metals,such as Cr,Co,Ni,Cu,Zn,Cd,Pb and Hg,as well as some basic physiochemical properties,including pH,particle size and organic matter content,were measured.Using the soil background concentrations of heavy metals in Shandong Province as standards,single factor indices and comprehensive indices of heavy metals were calculated to assess the degree of heavy metal contamination.The potential ecological risk index method was applied to evaluate the ecological risk of heavy metal contamination in riparian soil.The results showed that the riparian soil was mainly alkaline with a pH range of 5.67—8.66.The organic matter content was 2.60—33.74 g/kg with an average of 9.39 g/kg.The riparian soil had coarse granularity with an average particle size of 89.69 μm.Silt and sand grains were the main particles in riparian soil with average volume fractions of 50.33% and 38.48%.The average concentrations of Cr,Co,Ni,Cu,Zn,Cd,Pb and Hg were 53.03 mg/kg,10.33 mg/kg,24.96 mg/kg,18.38 mg/kg,56.13 mg/kg,0.142 mg/kg,22.48 mg/kg and 0.020 mg/kg,respectively.Heavy metal concentrations in the riparian soil samples were all lower than the heavy metal limit values of the class II environmental quality standard for soils in China(GB15618—1995).Heavy metal pollution in riparian soil was generally low and posed low ecological risk.The degree of contamination of the different heavy metals decreased as follows: Cd>Hg>Ni>Zn>Pb>Cr>Cu>Co and the potential ecological risk were in the order of Cd>Hg>Ni>Pb>Cu>Co>Cr>Zn.Thus,Cd and Hg most contributed to the ecological risk with average ratios of 46.8% and 33.6%.A higher degree of heavy metal pollution was found in riparian soil from Zhu Zhaoxin River,Liaohe River,Menlou Reservoir and Dongping Lake than riparian soil from other water source areas.Correlation analysis revealed that heavy metal concentrations were significantly and positively correlated with each other,and also with organic matter;in contrast,they were negatively correlated with average particle size.Hierarchical cluster analysis,based on Pearson correlation coefficients,was used to identify the sources of heavy metals in the riparian soils.The results suggested that the heavy metal concentrations in riparian soils were determined by both the soil parent materials and external sources related to human activities.Specifically,Cr,Co,Ni and Cu largely originated from soil parent materials;Zn and Cd were associated with contaminated surface runoff,Hg might be related to industry and domestic solid waste,and Pb probably derived from vehicle emissions.