【摘要】 采用单因子污染指数法（P_i）对四川盆地丘陵区凯江流域农田耕层土壤（0～20 cm）中4种重金属污染风险进行评价,并基于GIS平台,结合反比距离权重法（IDW）、径向基函数法（RBF）、普通克里格法（OK）、析取克里格法（DK）和概率克里格法（PK）分析研究区重金属的空间分布特征。结果表明,凯江流域土壤Cd、Hg、As和Pb平均含量分别为0.35、0.10、7.77 mg·kg^-1和22.54 mg·kg^-1,在空间分布上土壤Cd、As和Pb总体呈现以两个高值为中心向四周递减的趋势,土壤Hg则呈现西部高、东部低的特征。单因子污染指数评价结果表明,土样Cd、As、Hg和Pb的污染超标率（P_i≥1）分别为7.5%、0.5%、0和0。前4种空间插值的分级面积统计结果表明,研究区域土壤Pb、Hg和As均无污染超标,土壤Cd超标面积（P_i≥1）为0.14%～1.06%;概率克里格法风险评估结果表明,土壤Hg、Pb分别在P_i>0.3和P_i>0.2条件下无高风险概率,在阈值为1.0条件下,受到As污染的高概率（0.8～1.0）区域有1.05%,0.16%的区域面积有Cd污染超标风险（P=1.0）。因此,该区部分农田土壤主要受到Cd污染。更多还原

【Abstract】 Evaluation of heavy metal pollution is important for planning of regional-soil heavy metal contamination control and implementation of remediation projects.In this study,we employed a single-factor pollution index method（P_i）to assess the pollution of farmland topsoil（0～20 cm）of the Kaijiang watershed in the hilly area of the Sichuan basin by heavy metals.The inverse distance weighted method（IDW）,radial basis function method（RBF）,ordinary kriging method（OK）,disjunctive kriging method（DK）,and probability kriging method（PK）were applied to analyze the spatial distribution of heavy metals in the soil.The average contents of soil cadmium（Cd）,mercury（Hg）,arsenic（As）,and lead（Pb）were 0.35,0.10,7.77 mg·kg^-1,and 22.54 mg·kg^-1,respectively.With respect to the spatial distribution,soil Cd,As and Pb showed a decreasing trend from two high-value centers,and the soil Hg content was higher in the west and lower in the east.Statistical evaluation of single-factor P_i of all sampling points demonstrated that the over-standard rates（P_i≥1）of soil Cd,As,Hg and Pb were 7.5%,0.5%,0,and 0,respectively.The area ratios of spatial interpolation based on the IDW,RBF,OK,and DK methods indicated that the soil Pb,Hg and As had no over-standard area,whereas the percentages of the soil Cd over-standard area（P_i≥1）were in the range of 0.14%～1.06%.According to the risk assessment of probability kriging,soil Hg（P_i>0.3）and Pb（P_i>0.2）had no area with high-risk probability.When the threshold value of P_i was set to 1.0,1.05% of the research area had high probabilities（0.8～1.0）of being polluted by As,and 0.16% of the soil in the survey zones carried a risk of Cd pollution（P=1.0）.Therefore,some farmlands in the watershed were mainly polluted by Cd.更多还原