北京市得田沟和崎峰茶金矿周边土壤中重金属的粒径分布特征

以北京市得田沟和崎峰茶金矿周边土壤为研究对象,运用斯托克斯沉降法研究土壤颗粒组成及重金属在不同粒径中的分布特征.结果表明,土壤颗粒主要以0.15 mm粒级为主,含量达到51.19%~79.75%,其次为0.15~0.05 mm粒级土壤,含量为14.67%~38.99%,粒级0.05~0.01 mm土壤含量为0.18%~7.6%,粒级0.01 mm的土壤含量仅占1.71%~5.95%.除Ti和V外,其它金属元素的含量具有明显的粒级效应,随着土壤粒径的减小而增大,但大多数金属元素不在最细粒级上达到最大值,而是在0.002~0.001 mm粒级上最大.金属元素在不同粒级上的累积效应与粒级上的含量相一致,金属元素在较细粒级上的累积作用明显强于粗粒级.细粒级土壤含有较高的金属含量,对人类健康危害极大,应积极采取有效措施防止极细粒级土壤进入空气和水源.

Particle size distribution of heavy metals in soils around the Gold Mine of Detiangou-Qifengcha, Beijing

The particulate composition of soils by Stokes sedimentation method and the concentrations of heavy metals in these soils were investigated around the gold mine of Detiangou-Qifengcha in Beijing. The result showed that soil particles were mainly with size fractions >0.15 mm and 0.05~0.15 mm, and the content of <0.01 mm was very low. The content of metals (except of Ti and V) increased as the particle size decreased, however, the maximum content of most metals in particle size was at 0.002~0.001 mm, instead of <0.001 mm. The accumulative effect of metals in different particle sizes was similar as the content of metals, and the accumulation of metals in finer fractions was stronger than the coarser sizes. As finer particles are more detrimental to human health, effective measures should be adopted to prevent finer soils from entering the air and water.