铜陵矿区土壤中镉存在形态及生物有效性

采取Tessier连续提取法，研究铜陵矿区不同功能区表层土壤中镉的化学形态分布和生物有效性。结果表明，各种土壤中的镉含量全部高于地区背景值，主要来源与矿业活动有关，部分样品还有矿体的风化富集叠加，土壤镉污染指数PCd为1．15～79。镉含量依次为矿体风化土壤→废矿堆下垫土→市郊菜地土→矿区铜草土、路边土和稻田土→其它土壤。其形态分布，酸性土壤中以Fe-Mn氧化态和可交换态为主，其余三态相对较低；碱性土壤中有机态和残渣态比例较高，碳酸盐态和可交换态所占的比例低。土壤中生物可利用态镉的含量较高，占土壤总镉的60．20%-98．3％，生物不可利用态仅占1．7％-39．2％。

Speciation and bioavailability of cadmium in Tongling mining soils

Sequential extraction procedure developed by Tessier et al. was adopted to analyze the chemical speciation and their bio-availability of cadmium in different soils in Tongling mine area. The results showed that all kinds of soils is heavily polluted by cadmium from the mining activities such as copper mine smelting, and the ore weathering also added this enrichment in some sam- ples. The cadmium pollution index of soils is 1.15~79. Cadmium in soils is dominated in the Fe-Mn oxides species and exchangeable species in acid soils, and the carbonates species, organic matter species and minerals species are comparatively lower. In alkali soil, the amount of cadmium in different chemical special is in the order of Fe-Mn oxides species>organic matter species, minerals spe- cies>carbonates species>exchangeable species. The bioavailable cadmium is from 60.2% to 98.3% of total cadmium in soils while inert bioavailable fraction is from 1.7% to 39.2%.