鞍山某铁矿区土壤重金属形态分布及生物有效性分析

研究鞍山某铁矿区周边土壤中5种重金属（Cd、Pb、Cu、Zn和Ni）的全量和形态分布，采用风险评价编码（RAC）法及次生相与原生相分布比值（RSP）法对元素生物有效性和环境风险进行评价。研究结果表明，该区土壤中Cd和Ni全量超出了国家二级标准，Pb、Cu和Zn未超限，但在土壤中富集明显；各重金属生物有效态占比的大小顺序为Cd > Pb > Ni > Zn > Cu，Cd元素生物活性最高且毒性最强；5种重金属的RAC值大小依次为Cd（40.62%）> Pb（21.60%）> Ni（16.31%）> Cu（12.16%）> Zn（9.74%），RSP值大小依次为:Cd（1.31）> Pb（1.06）> Zn（0.94）> Ni（0.71）> Cu（0.39）。结合总量、生物有效性及形态学评价，该矿区土壤重金属Cd是生物活性最强、环境风险最高的元素，其次是Pb；Ni的生物有效性较低，但其全量已超标，因此应对该区Cd、Pb和Ni给予特别关注。 

Chemical Forms and Bioavailability of Heavy Metals in Soil Around an Iron Mine in Anshan

Total and morphological distribution of five heavy metals (Cd, Pb, Cu, Zn and Ni) in soil around the iron mine region were analyzed, the bioavailability and environmental risk were evaluated by means of risk assessment code (RAC) and the ratio of secondary phase and primary phase (RSP). The results showed that the total contents of Cd and Ni surpassed the Chinese soil quality standard class Ⅱ, while Pb, Zn and Cu not surpassed the standard. Pb, Zn and Cu accumulation took place in mining region. The bioavailability ratio of heavy metals were in the order of Cd > Pb > Ni > Zn > Cu, which indicated that Cd has the highest biological activity and environmental toxicity. The heavy metals in RAC were in order of Cd(40.62%) > Pb(21.60%) > Ni(16.31%) > Cu(12.16%) > Zn(9.74%)and in RSP were in order of Cd(1.31) > Pb(1.06) > Zn(0.94) > Ni(0.71) > Cu(0.39). Based on the results, the bioavailability and pollution risk of Cd is biggest in the soil around the iron mine, followed by the Pb pollution. The bioavailability of Ni is relatively low, but the total has been exceeded the standard. So more attention should be paid to Cd, Pb and Ni pollution.