广东揭阳土壤镉含量的空间分布特征及影响因素

以广东省揭阳市土壤为研究对象,采集了1 330个表层土壤(0~20 cm)样品和331个深层土壤(150~200 cm)样品,通过 GIS 空间分析技术、半变异函数拟合和方差分析等方法对研究区土壤镉含量的富集特征、空间分布、结构特征以及影响因素进行了系统分析。结果表明,研究区表层土壤镉含量的均值为0.09 mg/kg,高于该区土壤背景值,但低于GB 15618—2018《土壤环境质量农用地土壤污染风险管控标准(试行)》的标准值。通过富集因子法研究表明,研究区表层土壤镉主要为轻微污染和中度污染。从结构特征来看,研究区表层土壤镉含量呈中等空间相关性。揭阳市表层土壤镉含量高值区主要分布在人类活动密集的东部和南部地区。土地利用类型、成土母质和土壤类型是影响表层土壤镉含量的重要因素,在不同土地利用方式下,建筑用地土壤镉含量最高;不同成土母质中,第四纪沉积物土壤镉含量显著高于其他母质;不同土壤类型中,水稻土的镉含量相对较高。

Spatial Distribution Characteristics and Influencing Factors of Soil Cadmium Content in Jieyang of Guangdong Province

In this paper,1,330 topsoil(0-20 cm)samples and 331 deep soil(150-200 cm)samples were collected from Jieyang,Guangdong,China.The enrichment characteristics,spatial distribution,structural characteristics and influencing factors of soil cadmium content in the study area were systematically analyzed by the methods of enrichment factor,GIS spatial analysis,semi-variogram fitting and analysis of variance.The results showed that the average cadmium content in the topsoil was 0.09 mg/kg,which was higher than the soil background value of the area,but lower than“Soil Environmental Quality Risk Control Standard for Farmland Soils(Trial)(GB 15618-2018)”.According to the enrichment factor method,the cadmium content in topsoil of the study area was mainly slightly and moderately polluted.From the structural characteristics,the cadmium content in the topsoil of the study area was moderately spatially correlated.The high value areas of cadmium in topsoil of Jieyang City were mainly distributed in the eastern and southern areas where human activities were intensive.Land use types,soil parent materials and soil types were important factors affecting cadmium content in surface soil.Under different land use types,the cadmium content in construction land was the highest;In different parent materials,the cadmium content in the Quaternary sediments was significantly higher than other parent materials;In different soil types,the cadmium content in paddy soil was relatively high.