松嫩平原黑土核心区土壤砷空间变异特征及污染评价

基于多目标区域地球化学调查数据,采用地统计分析与GIS空间分析方法,对松嫩平原黑土核心区土壤As含量进行冷热点分析和空间变异特征分析,运用地累积指数法、潜在生态风险指数法对研究区土壤As污染进行了评价。结果表明:研究区土壤As含量范围在2.1～107.7 mg/kg,平均含量9.09 mg/kg,略高于黑龙江省松嫩平原土壤As含量背景值;土壤As高值聚类区主要分布在呼兰河上游,低值聚类区主要分布在呼兰河下游和松花江流域;土壤As含量具有强烈的空间自相关性,以结构性变异为主,空间分布受成土母质、水系等因素影响显著;研究区98.52%的地区为无污染的状态,99.88%的地区为低潜在生态风险。建议通过改善农业耕作方式、调整种植结构、减少农药和化肥使用量等人为因素来减缓土壤中As含量增加的趋势。

Spatial Variability and Pollution Evaluation of Soil Arsenic in the Core Area of Black Soil in Songnen Plain

Soil is the carrier of agricultural production, Therefore, it is of great significance to study heavy metal pollution in agricultural soil to ensure national food security. Based on the multi-objective regional geochemical survey data, the soil arsenic (As) content in the core area of black soil in Songnen Plain was analyzed by means of geostatistical analysis and GIS spatial analysis, and the soil As pollution in the study area was evaluated by means of geo-accumulation index and potential ecological risk index. The results showed that the content of soil As ranged from 2.1 to 107.7 mg/kg, and the average content was 9.09 mg/kg, slightly higher than the background value of soil As in Songnen Plain of Heilongjiang Province. The high-value clustering area of soil As was mainly distributed in the upper reaches of Hulan River, while the low-value clustering area was mainly distributed in the lower reaches of Hulan River and Songhua River basin. The content of As in soil has a strong spatial autocorrelation, which is dominated by structural variation. The spatial distribution of soil As is significantly affected by factors such as the parent material of the soil and water system. In the study area, 98.52% of the areas are pollution-free and 99.88% of the areas have low potential ecological risk. It is suggested to slow down the increase of As in the soil by improving agricultural cultivation methods, adjusting planting structure, reducing the use of pesticides, reducing the use of chemical fertilizer and other human factors.