武夷山茶园土壤重金属环境风险等级评价及溯源分析

为研究武夷山茶园土壤重金属环境风险现状及来源,通过多元统计对土壤中8种主要重金属元素的含量特征进行描述,并结合潜在生态风险指数进行评价,利用主成分分析来源。结果表明:(1)研究区土壤重金属Pb、Cd和Hg显著富集,分别是福建省土壤背景值的2.2、3.6和2.6倍;(2)Cu、Zn、Pb、Cr、Ni和As风险等级"低";Cd、Hg的风险等级以"中"和"较重"为主。整体茶园土壤综合潜在生态风险以"中"和"重"为主(78.9%)。(3)Pb为交通源因子;Cu、Cr和Ni的主要来源于成土母质;Hg为农业源因子;Zn受到自然地质背景和交通运输的共同控制;Cd除了交通源还有农业源。由于Cd和Hg元素的潜在生态风险高,因此,应特别注意茶园农业源的影响。

Risk Evaluation and Source Tracing on Heavy Metal Contaminations in Soil at Tea Plantations in Wuyishan

Risk evaluation and source tracing on the environmental pollution from heavy metal contamination in soil at tea plantations in Wuyishan were conducted.Contents of 8 major heavy metals in the soil samples were analyzed using multivariate statistics,evaluated according to the Hakanson potential ecological risk assessment index,and traced to their origins by a principal component analysis.The results indicated that (1)the average concentrations of Pb,Cd,and Hg were 2.2,3.6,and 2.6 times,respectively,higher than the respective reference values for Fujian standards on these elements,while,although less severe,those of Cu,Zn,Ni,Cr,and Pb also apparently showed their presences in the surface soils;(2)using the potential ecological risk assessment index,the risk levels of Cd and Hg were categorized as " medium" and " moderately heavy," those of Cu,Zn,Pb,Cr,Ni and As graded as "low," and overall,the soils at the plantations were under" medium" and" heavy" levels (78.9%);and,(3)the principal component analysis suggested that the main source of Pb contamination stemmed from traffic pollution, those of Cu,Cr,and Ni from the natural components in soil at the sites,that of Hg from agricultural sources,that of Zn from natural, geological background and/or traffic at the surrounding areas, and, that of Cd from transportation and/or agricultural origins.Consequently,special attention must be paid on Cd and Hg as they also inherently post greater risks than others on human health.