汉阴县土壤硒的分布特征

摘要

To study the distribution characteristics of selenium in Hanyin, Shaanxi, we collected 859 samples of surface soils, using Hydride Generation Atomic Fluorescence Spectrometry(HG-AFS)analyzed its selenium content. The variation function was constructed in the GS+, distribution map of soil total selenium content in Hanyin was drawn by ArcGIS, and analyzed the level of soil selenium content in the area, distribution characteristics and relationship with the formation. The results showed that the soil selenium content ranges was 0.004 9-9.770 0 mg/kg, average value of 0.49 mg/kg, coefficient of variation 2.03, conform to lognormal distribution. The rang(R)was 2 328 m, the nugget was 0.08 and the spatial heterogeneity index was 0.4. This indicated that the variation in total selenium content mainly contributed to the structure factor, and there was a strong spatial autocorrelation. Soil selenium content in the range was larger, north-south high and middle lower. There were two continuous distribution of selenium-rich area, account for 71.7%of the total area of Hanyin. The distribution of black carbonaceous rocks in Cambrian-Ordovician-Silurian(except Meiziya group)were main source and consistent with selenium enriched area.%为了探讨汉阴县土壤硒含量水平及分布特征，采集了550个表层土壤样品，用原子荧光检测了硒含量，在地统计学软件GS+中构建了变异函数，用GIS软件绘制了汉阴县土壤全硒含量分布图，同时分析了该区土壤硒含量水平、分布特征以及与地层的关系。结果表明，研究区土壤硒含量最低0.0049 mg/kg，最高9.7700 mg/kg，平均值0.49 mg/kg，变异系数2.03，土壤硒含量服从对数正态分布，变程R=2328 m，块金值为0.08，空间异质性指数为0.4，说明研究区土壤硒含量的变异主要是由结构性因素引起的，空间自相关性较强；土壤中硒含量变化范围较大，分布不均匀，南北高，中间较低，呈现出2条连续分布的富硒区，占汉阴县总面积的71.7%，富硒区分布与寒武—奥陶—志留系（除梅子垭组）的黑色含碳岩系分布一致，是富硒区土壤硒的主要来源。