关键词: 铅锌废渣场, 耕地, 林地, 重金属形态, 植物

Abstract: We investigated the heavy metal content and form changes in soil and enrichment characteristics in soil-plant systems under different land use types around a Pb-Zn waste site, with two typical land-use types (arable land, forest land) and six common plant species (corn, radish, buckwheat, Yunnan pine, cedar, viburnum) as the research objects. Samples were collected from different purts of the six species and soil. Contents and forms of heavy metals (Cr, Ni, Cu, Zn, As, Cd, Pb) in soil and plants were analyzed. The bioconcentration factor and translocation factor were used to evaluate the enrichment capacity of aboveground and belowground plant organs for heavy metals, and to investigate the correlation between heavy metal forms in soil, heavy metals in plants, and soil pH. The results showed that the contents of heavy metals in soil, except Cd, were lower in forest than that in cropland. Soil Cr, Ni, Cu, and As were mainly in the residue state, Pb in the reducible and residue states, and Cd and Zn in the acid-extractable and residue states. Zn and Cd had the strongest migration ability in plant-soil systems. Maize showed strong root enrichment and weak transport capacity for heavy metals, while radish showed an opposite pattern. Viburnum showed good accumulation and migration ability of heavy metals. Most heavy metals in the weakly acid-extracted and reducible forms in the study area were easily enriched by plants. The weakly acid-extractable and reducible forms of Zn, Cd, and Pb accounted for a relatively high proportion, resulting in a significant positive correlation between the contents in soil and plants (P<0.01). Considering the high availability of Cd, Pb, and Zn in soils around the slag yard, sufficient attention should be paid to soil remediation and treatment.

Key words: lead-zinc waste slag field, arable land, forest land, heavy metal form, plant