关键词: 石灰性紫色土, 土壤剖面, 锌形态

Abstract: An investigation was made on the farmland soil heavy metals concentration and their spatial distribution in a former artisanal zinc-smelting zone of Xinguanzhai, Hezhang County, Guizhou Province, aimed to assess the soil heavy metals contamination after the ceasing of artisanal zinc-smelting activities. The average concentrations of Pb, Zn, Cd, Hg, Cu, and As in surface soil were 337, 648, 9.0, 0.44, 121, and 17 mg·kg^-1, being 7.5, 7.9, 26.4, 2.2, 4.7 and 0.8 times as higher as the background values of Guizhou farmland soils, respectively. The single factor pollution index revealed that Cd was the most serious contaminant, followed by Zn, Pb, As, Hg, and Cu. The integral pollution index indicated that within the range of 4 km in the zone, surface soil underwent serious heavy metals combined contamination. Most of the heavy metals accumulated in upper 30 cm soil layer and reduced with soil depth, while Zn and Cd moved downward 15-20 cm due to their higher activity and mobility.

Key words: Calcareous purple soil, Soil profile, Zinc form