海南岛琼山热带土壤中重金属分布和矿物特征的关系

本文探讨了海南岛玄武岩上发育的热带地球化学景观中土壤重金属与机械组成,矿物成分和矿物组合之间的关系。结果表明,砖红壤粘粒并不富集重金属元素,这与砖红壤各粒级矿物分布特征有关,在其粉粒级和砂粒级中有大量氧化铁矿物,面粘粒级中主要是高岭石和三水铝矿。此外,水稻土随粒径变大,重金属含量减少,这同水稻土随粒径增大,粘土矿物迅速减少,长石、石英增多有关。这和一般土壤重金属在不同粒级中分布规律相符合。

RELATIONSHIP BETWEEN DISTRIBUTION AND MINERALOGICAL PROPERTIES OF HAVEY METALS IN TROPICAL SOILS OF QIONGSHAN, HAINAN ISLAND

Generally, heavy metal hays a tendency to 1.e enriched in the clay of soil, but from the preliminary study on the relationships between some heavy metals and the mechanical composition of soil, together with the composition of minerals in the soils of Hainan Fsland, it was found that the clay fraction of latosol was not enrich by heavy metals, whereas with decreasing particle size of paddy soil that was situated on the same tropical landscape as the latosol was, concentrations of the heavy metals increased and it was highest in the clay fraction(<0.001mm). In order to reveal the cause of the distribution of heavy metals, the different fractions of particle-sizes of the soils were identified by x-ray diffration. The silt group and sand group of the latosol contained large amount of iron oxides, Lut its clay group mainly consisted of kaolinite and gibbsite. Therefore, the distribution characteristic of heavy metals in the latosol is closely relative to iron oxides adsorbing a.u containing heavy metal. However, X-ray diffration analyses showed that with the incerase of particle size of paddy sail, its heavy metal content decreased, which is reaafed to quartz and feldspar increasing and clay minerals decreasing with the increasing of particle size of the soil. The distribution of heavy metals in the paddy soil conforms to that of other soils.