宜宾兴文县僰王山镇水田土壤中硒形态分布特征及研究

Study on the Speciation Distribution of Selenium in Paddy Field Soil of Bowangshan Town,Xingwen County,Yibin City

为了客观分析土壤中硒形态分布特征及硒有效性影响因素,依据硒不同形态下的溶解度不同,采用四步五态连续浸提取技术,由弱到强的选择顺序提取僰王山镇水田土壤中硒的水溶态、可交换态、有机质结合态、硫化物/硒化物态、残渣态这5种形态,并用原子荧光光谱法分析和氢化物发生-原子荧光光谱法测定了土壤样品中5种形态硒和总硒的含量。初步总结了研究区水田土壤硒含量特征和硒形态分布特征。研究结果发现,僰王山镇水田土壤总硒含量变化范围为0.51~0.93 mg/kg,平均值0.714 mg/kg,远远超过全国土壤总硒平均值0.290 mg/kg,且超过了目前认为的富硒土壤的标准值0.4 mg/kg。从土壤中5种形态分析结果所占比例来看,有机质结合态和硫化物/硒化物态硒是硒元素的主要赋存形态,两者占土壤总硒含量的54.63%,反应了研究区土壤中硒富集与有机质结合态存在密切关系。

In order to objectively analyze the distribution characteristics of selenium forms in soil and the influencing factors of selenium availability,according to the different solubility of different forms of selenium,the four-step five-state sequential extraction procedure was used in this paper to extract five forms of selenium in paddy field soil of Bowangshan town which are water soluble,exchangeable,organic matter combination,sulfide/selenide,residual.The contents of five kinds of selenium and total selenium in soil samples were determined by atomic fluorescence spectrometry and hydride generation-atomic fluorescence spectrometry.The characteristics of selenium content and selenium form distribution in paddy soil in the study area were summarized.The results showed that the variation range of total selenium content in paddy field of Bo Wangshan town was 0.51~0.93mg/kg,with an average of 0.714 mg/kg,which was much higher than the national average of 0.290 mg/kg,and exceeded the current standard value of 0.4 mg/kg for selenium-rich soil.According to the proportion of the five soil forms,the organic matter binding form and sulfide/selenide selenium form were the main forms,which account for 54.63%of the total selenium content in soil,indicating that there is a close relationship between selenium enrichment and organic matter binding in the soil of the study area.