北京市平原区土壤中硒的含量和分布

Content and Distribution of Selenium in Soil of Beijing Plain

通过对北京平原土壤硒含量调查和研究,发现北京平原分布有高硒土壤,其特征为沿平原区西部山前断续出现,在北京市区零星分布。表层土壤硒含量为0.04～5.26 mg/kg,平均值为0.20 mg/kg,深层土壤硒含量为0.043～0.22mg/kg,平均值为0.081 mg/kg,总体趋势是硒在表层土壤富集;各类岩石中以炭质页岩中含硒量最高,北京西部富硒炭质页岩的风化可能为平原区土壤硒的来源。相关性分析表明,土壤中Se与有机质呈正相关性,有机质对表层土壤Se具有强烈的吸附与固定作用。

Based on geochemical study of soil,the high selenium soil in Beijing Plain was discovered distributing discontinuously around the west of plain and scatters in the city.The content of selenium in surface soil is from 0.04 to 5.26 mg/kg,with the average value of 0.20 mg/kg.The content of selenium in deep soil is from 0.043 to 0.22 mg/kg,with the average value of 0.081 mg/kg.The selenium tends to enrich in the surface soil.The content of selenium in shale is higher than that in other types of rocks.The source of selenium in soils is from the weathering of Se-rich carbonaceous rocks in the west part of Beijing.Studies show that the soil organic matter is closely related to selenium,and that organic matter plays a key role in adsorption and fixation of selenium in surface soil.