Taking the Jianghugongmi producing area as the research object, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the soil of the study area were sampled and determined. The correlation of heavy metals was discussed using the multivariate statistical method, the spatial distribution interpolation analysis of heavy metals was carried out using ArcGIS 10.2, the quantitative source analysis of heavy metal pollution was carried out using the enrichment factor (EF) and PMF methods, and the potential ecological risk was evaluated. The results showed that the contents of the soil heavy metals As, Cd, Cu, Hg, Pb, and Zn were lower than the screening values specified in the standard for soil pollution risk control of agricultural land (GB 15618-2018), and the soil ecological environment risk was low; the maximum values of Cr and Ni exceeded the risk screening values, but the risk was low. The main distribution range of pH in the study area was 6.05-6.69, which was suitable for rice growth. The Mohe River indicated the spatial distribution of pH and heavy metals, which was closely related to the supergene geochemical characteristics of the elements. However, Hg and Cd showed different spatial distribution characteristics under human influence. Hg was distributed in the middle and high value distribution area along the west side of the river, and the spatial distribution of Cd was significantly different from north to south. The quantitative source analysis results based on the EF method and PMF showed that the main sources of heavy metals in the study area were agricultural sources, mixed sources, coal sources, and natural sources. The contribution rates of various sources accounted for 24.2%, 35.4%, 9.5%, and 30.9%, respectively. The medium strong ecological risk points of Hg in the study area were distributed along the west side of the Mohe River, whereas the moderate potential ecological risk points of Cd were concentrated in the cultivated land on both sides of the Mohe River, and the potential ecological risk index (Er) of the other elements was<40. Cd and Hg were the main potential ecological risk elements in the study area, whereas Cd was still the main potential pollution element in the cultivated land soil in the study area.
Keywords: Jianghugongmi; heavy metals; potential ecological risk index; source apportionment; spatial distribution.