摘要
在对中国东北污染源附近农田土壤中铅、镉、铬和砷化学形态分析的基础上进行了重金属的生物有效性评价,结果表明,重金属主要累积在农田表层0～20cm的土壤中,表层土壤中有一种或两种重金属的总量分别超过国家土壤环境质量相应的标准值。所研究土壤中,铅、铬和砷以残渣态为主,其中残渣态铅占52.9%～80.1%,铬占81.0%～90.5%,砷占42.1%～82.9%。镉以有机结合态占优势,相对含量为19.5%～57%。铅、镉、铬和砷可交换态的相对含量均较低(0.02%～3.67%)。3种土壤中,重金属生物有效性的大小顺序均为镉>砷>铅>铬,迁移能力的大小顺序为镉≥砷>铅≥铬,镉的生物有效性和迁移能力都是最大的,说明镉的生物有效性最高,应给予更多的关注。
Chemical speciation of heavy metals （ Pb, Cd, Cr and As ） in three farmland soils near pollutant sources in northeast China were analyzed in this study. On the basis of analysis of the chemical speciation, bioactivity and phytoremediation about heavy metals in soils were evaluated and discussed, respectively. The result showed that heavy metal mainly accumulated in subsoil （0-20 cm ）, and the contents of heavy metals in subsoil in individual region had surpassed different level of standard values ＂Soil environment quality standard＂. The majorities of Pb, Cr and Cd were found to be in residual fraction, with the relative concentrations being 52.9%~80.1%, 81.0%-90.5% and 42.1%-82.9%, respectively. Cd existed mainly in the organic phase and the relative concentration ranged from 19.5% to 57.0%. There was a little amount of exchangeable Pb, Cd, Cr and As （0.02%-3.67%）. The bioavailability and mobility of heavy metals in the three soils followed Cd 〉 As〉Pb〉Cr, and Cd ≥ As〉Pb ≥ Cr. The highest proportions of bioavailability and mobility of Cd were found among all metals in the three soils, which indicated that cadmium was the most active, and it should be paid more attention to.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2009年第8期1573-1577,共5页
Journal of Agro-Environment Science
基金
国家重点基础研究发展计划973项目(2004CB418505)
关键词
土壤
重金属
化学形态
生物有效性
植物修复
soil
heavy metal
chemical speeiation
bioactivity
phytoremediation
