重庆市酉阳县南部农田土壤重金属污染评估及来源解析

为了探究矿业活动及地质背景对土壤环境的影响，在重庆市酉阳县南部农用地中采集了土壤组合样品156件，分析了土壤中重金属的含量及pH，基于地统计法、单因子指数法及内梅罗指数法对土壤重金属污染状况进行了评价，利用主成分分析/绝对主成分分数（PCA/APCS）受体模型讨论土壤重金属的来源.结果表明，土壤Cd污染呈面状分布，而土壤Hg主要表现为点状污染，土壤中-重度污染主要分布在涂市乡、麻旺镇及龙潭镇三镇交界处，土壤以酸性为主，出现农作物污染的风险较高；指示克里格法评价结果显示，三镇交接处及涂市乡北部有较高的土壤污染概率；主成分分析/绝对主成分分数（PCA/APCS）受体模型分析结果显示，土壤As、Cd、Cr及Ni的来源主要受到地质背景的控制，土壤Hg与Pb、Zn主要受到矿业活动的控制，土壤Cu同时受到地质背景和矿业活动的影响；此外，农业活动也是土壤As、Cd、Pb、Cu及Zn等元素来源之一.研究区土壤中-重度污染主要是由矿业活动引起的，而地质背景导致的土壤重金属污染主要为轻度污染.该研究可为典型区域土地安全利用及土壤污染防治提供理论基础.

Assessment and Source Analysis of Heavy Metal Pollution in Farmland Soils in Southern Youyang County, Chongqing

To investigate the impact of mining activities and geological background on the soil environment, 156 soil samples were collected from an agricultural land in southern Youyang County, Chongqing. The content and pH of heavy metals in the soil were analyzed, and the Nemerow index method was used to evaluate the pollution status of soil heavy metals. The source of soil heavy metals was discussed using the principal component analysis/absolute principal component score (PCA/APCS) receptor model. The results showed that the soil Cd pollution was distributed in a planar shape, while soil Hg mainly appeared as point pollution. The medium-severe soil pollution was mainly distributed at the junction of Tushi Town, Mawang Town, and Longtan Town, where the soil was predominantly acidic and there was a higher risk of crop contamination; the indicator Kriging evaluation results showed that there was a higher probability of soil contamination at the junction of the three towns and the northern part of Tushi Township. The results of the PCA/APCS receptor model analysis showed that the sources of soil As, Cd, Cr, and Ni were mainly controlled by geological background; soil Hg, Pb, and Zn were mainly controlled by mining activities; further, soil Cu was affected by both geological background and mining activities. In addition, the agricultural activities were also one of the sources of soil As, Cd, Pb, Cu, and Zn. The medium-heavy pollution of the soil in the study area was mainly caused by mining activities, while the heavy metal pollution of the soil caused by geological background was mainly light pollution. This study can provide a theoretical basis for the safe use of land and the prevention and control of soil pollution in typical regions.