• 关键词：耕地土壤  重金属  喀斯特  正定矩阵因子分解  污染评价

• 基金项目：国家自然科学基金（No.61540072）

• 张宏泽
• 贵州师范大学，地理与环境科学学院，贵阳 550025

• 崔文刚
• 贵州师范大学，地理与环境科学学院，贵阳 550025

• 黄月美
• 贵州师范大学，地理与环境科学学院，贵阳 550025

• 李云路
• 贵州师范大学，地理与环境科学学院，贵阳 550025

• 钟昕
• 贵州师范大学，地理与环境科学学院，贵阳 550025

• 王龙
• 贵州师范大学，地理与环境科学学院，贵阳 550025

• 摘要：土壤健康状况是制定土壤可持续发展策略的基础.为阐明黔中喀斯特地区矿区周边耕地土壤重金属 （Cd、Hg、As、Pb和Cr） 的空间分布特征、污染现状及其来源，本研究按网格法采集378份耕地土壤样本，测定五项重金属含量，基于污染负荷指数法和潜在生态风险指数法评价重金属超标程度，运用地统计学分析重金属空间特征，应用正定矩阵因子分解法解析重金属来源.研究结果表明：Cd、Hg、As、Pb和Cr的平均含量分别为0.41、0.28、26.1、53.7和82.3 mg·kg^-1；污染程度从高到低为Hg>Pb>As>Cr>Cd，对耕地土壤潜在生态危害的影响程度从大到小为Hg>Cd>As>Pb>Cr，Hg是最主要的污染因子；在空间分布上， Hg的含量高值区呈面状分布，Cd、As、Pb和Cr含量高值区多呈点状分布，Cd、Hg和Pb受结构性因素和随机性因素共同影响，As和Cr主要受结构性因素影响；PMF定量解析出大气源贡献率为19.12%，自然源贡献率为18.81%，岩性源贡献率为31.46%，工业源贡献率为30.61%.大气沉降和工业活动是导致耕地土壤重金属污染的主要原因.

• Abstract：The status of soil health is the basis for the formulation of the soil sustainable development strategy. In the present study， 378 samples of farmland soil around the mining area were collected from the karst region of central Guizhou Province， according to the grid method， to determine the contents of five heavy metals （Cd， Hg， As， Pb， and Cr） and make the spatial distribution characteristics， the contaminated status and the sources of them clear. Based on the contamination load index and potential ecological risk index， the excessive degrees of the heavy metals in the farmland soil were evaluated. The spatial characteristics and the sources of the heavy metals were analyzed by geostatistics and the positive definite matrix factorization， respectively. The results showed that the average contents of Cd， Hg， As， Pb， and Cr are 0.41， 0.28， 26.1， 53.7， and 82.3 mg·kg^-1， respectively. The degree of contamination from high to low is Hg > Pb > As > Cr > Cd； however， the degree of the impact on the potential ecological hazards of farmland soil from large to small is Hg > Cd > As > Pb > Cr. It was noticed that Hg is the most contamination factor among the five heavy metals. It was also noticed that the areas with a higher Hg content show a planar distribution， while the areas with a higher content of Cd， As， Pb， and Cr show a point distribution. Further， Cd， Hg， and Pb are affected by both the structural and random factors， while As and Cr are mainly affected by the structural factors. The PMF quantitative analysis showed that the contribution rates of atmospheric， natural， lithologic， and industrial sources are 19.12%， 18.81%， 31.46%， and 30.61%， respectively. The atmospheric deposition and the industrial activities were found to be the main causes of the heavy metal contamination in the farmland soil.

• Key words：farmland soil  heavy mentals  karst  positive matrix factorization  contamination assessment

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