ABSTRACT
Based on the land quality geochemical survey results in the southwest cultivated area of Nanyang Basin, the content, spatial distribution, and enrichment characteristics of Ge in surface soil (0-20 cm) and deep soil (150-200 cm) in the eastern mountainous area of Nanyang Basin were studied, and the influencing factors of Ge in the surface soil were analyzed. The results showed that the average ω(Ge) in the surface soil and deep soil were 1.39 mg·kg-1 and 1.45 mg·kg-1, respectively. In the study area, 32.22% of surface soil and 12.77% of surface soil was rich in Ge, and the rich areas of the surface soil Ge were mainly distributed in the metamorphic rock and granite-dominant development areas. The optimal theoretical model of surface soil Ge variogram in the study area was a spherical model, and the nugget effect value was 0.434, indicating that surface soil Ge had moderate spatial correlation due to the joint influence of random factors and structural factors. The enrichment factor showed that 93.61% of Ge sites in the topsoil were mainly affected by natural factors, whereas 6.39% of Ge sites were significantly affected by human factors. The source of Ge in soil in the study area was mainly affected by the parent materials of soil formation, but the enrichment of Ge in surface soil was mainly affected by the Fe, Mn oxides, quartz, and pH in the soil.
Subject(s)
Germanium , Soil Pollutants , Humans , Soil/chemistry , Soil Pollutants/analysisABSTRACT
The spatial distribution, pollution degree, and ecological risk of heavy metals in the soil were studied by analyzing the contents of As, Hg, Cd, Cr, Pb, Zn, Ni, and Cu and pH values in surface soil samples of the eastern mountainous area of the Nanyang basin. The results showed that the contents of Cd, Cu, Cr, Ni, Pb, Zn, and As in the soil exceeded the screening value of soil pollution risk. The spatial distribution of soil heavy metals displayed regional-and island-shaped. The highest concentration of heavy metals was found in the south of the study area, where a mining area is located. Most of the samples had no pollution levels except some samples with high contents of Cd. For As, Cr, Pb, Zn, Ni, and Cu, the potential ecological risk of most samples were low, while Cd and Hg posed medium risk in most areas. The areas with high and relatively high ecological risk index accounted for 58.93% and 37.66%, respectively. Soil Hg, Cd, and Pb contents were related to anthropogenic activities such mineral mining. As derives from geological processes, while Zn, Ni, Cr, and Cu are both controlled by anthropogenic activities and geological processes. The mining of mineral resources is the main driving factor of soil heavy metal pollution and ecological risk in the study area.
