重庆地区紫色土锗的背景含量及分布特征

对重庆地区分布的5种主要紫色土的116个背景土壤剖面,261个土样中的锗含量及分布进行了研究,结果表明:紫色土中锗的含量服从对数正态分布,几何均值为0.67×/÷1.4 mg/kg,算术均值为(0.71±0.26)mg/kg,略低于世界土壤平均值(1.0 mg/kg).背景土壤剖面C层锗含量高于A层、B层,但在燃煤所致降尘和酸雨重污染地区及某冶炼厂附近土壤(灰棕紫泥属)中,其表层锗含量明显高于底层,亦高于其它非污染地区同属土壤表层,因此,局部地区土壤可能存在锗污染问题,值得重视.紫色土壤锗含量与土壤阳离子交换量(CEC),Cu含量呈显著负相关,与土壤Pb,As含量呈显著正相关,而与土壤pH、有机质(OM)、碳酸盐含量及土壤其它化学成分(Hg,CA,Zn,Al_2O_3,Fe_2O_3,K_2O.Na_2O,CaO.MgO,Mn,Cr,Ni,TiO_2)间相关性很差.

Background Values and Distribution Characteristics of Germanium of Purple soils in Chongqing Areas

The contents and distribution characteristics of Ge in 261soil samples collected from 116 background soil profiles for five main types of purple soils in Chongqing areas were studied. Results showed that Ge contents in purple soils were submitted to logarithmic-normal distribution pattern, and their geometric and arithmetical mean value were 0. 67×/÷l. 4 mg/kg and (0. 71 ± 0. 26) mg/kg respectively which was slightly lower than the average soil Ge contentd(1. 0 mg/kg)of the world. In soil profiles, the Ge contents in different layers showed a sequence of horizon C>horizon A and B for the background soil samples, and surface soils > undersoils for the soil samples obtained from two sites heavily polluted by acid rains resulted from coal burning or contaminated by wastes discharged from a lead-smelting plant. The Ge contents of surface soils from these two sites were also higher than those from other non-polluted sites. So it is noteworthy that there might be or have been soil pollution of Ge in some specific areas. There existed significant negative correlations between soil Ge contents and soil Cu contents and CEC, and significant positive correlations between soil Ge contents and soil Pb and As contents. But the correlations between soil Ge contents and soil pH, OM, the contents of carbonates, and other soil chemical elements ( Hg, Cd, Zn, A1_2O_3, Fe_2O_3, K_2O, Na_20,CaO,MgO,Mn,Cr,Ni,TiO_2) were weak.