中文摘要：

以海口、琼海和屯昌的典型热带林地土壤为研究对象,采用干筛法获得6个粒级的土壤团聚体颗粒组.用ICP-MS测定了本土和不同团聚体颗粒中重金属Cr、Ni、Cu、Zn、Cd、As和Pb的含量,并对其分布特征及对有机碳和铁的响应进行了解析.研究表明,重金属在土壤各粒径团聚体颗粒组中差异性分布,随着团聚体粒径的减小而呈现富集增大的趋势,其中Cr、Ni、Cu、Zn、Cd和Cd主要富集在粉-黏团聚体（〈53μm）颗粒中;As主要赋存在53～1 000μm的颗粒组中.总体来讲,微团聚体（〈250μm）对土壤重金属含量贡献为14.38%～65.04%,其中粉粒级团聚体（〈53μm）的贡献为2.61%～32.01%.有机碳和铁氧化物含量随着团聚体粒径减小而升高,并与除了As及海口的Cd和Pb以外的其他重金属分布具有显著相关性.

英文摘要：

Three tropical forest soils were collected from Haikou, Qionghai and Tunchang in Hainan Island. Soil particle size fractionations were conducted using the standard dry-sieving procedure. Distribution of heavy metals in bulk samples and particle size fractions was determined by ICP-MS. The distribution characteristics and the response to organic carbon and iron were discussed. The results showed that the distribution of heavy metals was highly associated with the particle size fractions and variable patterns were found,which decreased with the increasing size. The accumulation of Cr,Ni, Cu,Zn, Cd and Cd was predominantly contributed by the particles finer than 〈 53 μm in diameter,whereas As mainly accumulated in particle size of 53-1 000 μm. Generally, the microaggregate （ 〈250 μm） contributed 14. 38%-65.04% of heavy metals to the contents in bulk soil and the silt-clay aggregates （ 〈 53 μm） contributed 2.61% -32.01%.. The content of heavy metals except for As and Cd and Pb in Haikou soil in these different size fractions were controlled by the organic carbon and iron contents, which increased with the decreasing particle size.