Analysis of Existing Speciation and Evaluation of Heavy Metals Pollution of Soil in a Shooting Range

摘要

In this paper, we have made an investigation and analysis of the concentrations of Pb and Cu in the surface soil samples from a small arms shooting range in Guangxi Province of China by using the U.S.EPA3050B (HNO_3-H_2O_2) method, and evaluated the pollution in the sampling area through the single factor index method and the composite pollution index Nemrow method. The results of our investigation and analysis showed that the soil of the small arms shooting range is heavily polluted by heavy metals, and the main pollution elements are Pb and Cu. The composite pollution index reached 59.18, and the single-factor pollution indexes of Pb and Cu have been the highest in the area of dropping bombs, which reached 72.90 and 10.12 respectively, indicating that the pollution has been to a serious level. The sources of heavy metal pollution comprise residual bullets and cartridge cases. We have also done analysis of the concurrent speciation of Pb and Cu in the soil with the sequential extraction method of Tessier, and discovered that the chemical speciation distribution order stands as follows: Resid-Pb ＞ FeMnO-Pb ＞ Org-Pb ＞ Carb-Pb ＞ Exch-Pb. As to the distribution characteristics of Cu, the order can also be listed as follows: Resid-Cu ＞ Org-Cu ＞ FeMnO-Cu ＞ Carb-Cu ＞ Exch-Cu. It can be seen that heavy metal Pb do much more serious to the ecological environmental contamination risk. Once the environmental conditions change, Pb and Cu can be easily transformed into bioavailability speciation. Because the pollution of heavy metal Pb and Cu in shooting range is serious, it is unfeasible to turn the shooting range soil into agricultural soil.