临沂植烟土壤重金属空间分布特征与生态健康风险评价

Spatial Distribution, Potential Ecological and Health Risk Assessment of Heavy Metals in Surface Soils from Tobacco Cultivating Areas of Linyi, Shandong Province, China

土壤重金属空间分布与风险评价对土壤重金属污染防治具有重要的指导意义。以传统适宜烤烟种植区山东省临沂市为研究对象,通过布点采样和地理信息系统制图,分析了土壤重金属的空间分布以及地区、土类间的差异,采用地积累指数、污染指数分析了土壤重金属富集污染水平,并对土壤重金属潜在生态风险和人体健康风险进行了评价。结果表明,临沂植烟耕层土壤重金属As、Cd、Cr、Cu、Hg、Ni、Pb和Zn平均含量分别为3.85、0.09、47.56、14.45、0.07、18.04、17.82和29.21 mg/kg;空间分布上,北部、中部和西南地区土壤重金属含量相对较高;8种重金属中仅Cd和Hg在部分土壤中表现出富集和污染;土壤重金属潜在生态风险大小顺序为Hg>Cd>As>Ni>Pb>Cu>Cr>Zn,其中部分土壤Cd和Hg对当地环境具有显著潜在生态风险;而土壤中所有重金属均没有显著的人体健康风险。因此,临沂植烟土壤存在一定程度的Cd和Hg污染风险,应采取措施进行控制。

The spatial distribution and risk assessment of heavy metals are the foundation of soil remediation.The heavy metals(As,Cd,Cr,Cu,Hg,Ni,Pb,and Zn)in the surface soils of tobacco(Nicotiana tabacum L.)fields in Linyi City of Shandong Province,a traditional tobacco growing area,were collected and determined,and the difference between counties and soil types was analyzed,with spatial distribution maps generated by the geographic information system.The enrichment of heavy metals in soil was assessed by index of geo-accumulation and pollution index,and the risk assessment included potentially ecological risk and health risk assessment.The results showed that,(1)the mean heavy metal concentrations in Linyi tobacco growing soils were 3.85,0.09,47.56,14.45,0.07,18.04,17.82 and 29.21 mg/kg,respectively;(2)the concentrations of heavy metals in soil samples from north,middle and southwest of Linyi were relatively higher than those from other areas;(3)some soil samples were enriched with Cd and/or Hg,which were the only two metals posing a potentially high ecological risk to the local environment,and the order of ecological risk for the heavy metals was Hg>Cd>As>Ni>Pb>Cu>Cr>Zn;(4)The health risk assessment showed no considerable non-carcinogenic or carcinogenic risks for children and adults from these elements.