An investigation was carried out to assess heavy metal contamination in the soils of a local town in Jiangsu province. Specifically, based on the concentration of As, Cd, Hg, and Pb in 190 topsoil samples, the distribution features of heavy metals in the soils were analyzed and the pollution status was assessed synthetically by applying the Nemerow integrated pollution index and the pollution load index. In the topsoil, the average concentrations of As, Cd, and Pb were higher than the background values for soil, but concentrations of Hg were lower than background values. The distributions of the four types of heavy metals were indicative of point source pollution. The areas with high concentrations of As were mainly distributed in the western part of the town, while the areas with high concentrations of Cd and Pb were mainly distributed in the center of the town. The areas with high concentrations of Hg were mainly distributed in the eastern and northeastern parts of the town. The Nemerow integrated pollution index results showed that the categories for non-pollution levels, dangerous levels, slight pollution levels, moderate pollution levels, and high pollution levels accounted for 5.79%, 32.11%, 52.11%, 4.74%, and 5.26% of the study region, respectively. Moreover, the pollution load index results showed that the categories for non-pollution levels, slight pollution levels, moderate pollution levels, and high pollution levels accounted for 73.69%, 25.26%, 1.05%, and 0% of the study region, respectively. In terms of correspondence in the evaluation results for the two methods, 55.26% of the samples were classified similarly and 44.74% of the samples were classified differently. However, both evaluation methods clearly indicated that pollution levels gradually decrease as one moves from the center of the town to the edges.
- Heavy metals pollution in the soils
- Nemerow integrated pollution index
- Pollution load index