山东沂南土壤-植物系统中硒生物有效性评价

Evaluation of Selenium Bioavailability in the Soil-Plant System of Yinan,Shandong Province

为评价山东沂南富硒土壤中的硒在不同作物中的生物有效性并推测其来源,对研究区的土壤、植物和岩石样品进行对应采集,采用ICP-MS等测试了各样品硒元素的总质量分数和水溶态、弱酸提取态、可还原态、可氧化态、残渣态5种形态分量的质量分数,并对结果进行对比分析。结果表明:土壤硒总质量分数受空间位置及水系约束明显;有效硒质量分数与硒总质量分数正相关,空间分布一致;土壤硒总质量分数与氮、磷质量分数正相关;土壤中硒的存在形态以亚硒酸盐为主。研究区富硒土壤上生长的花生、西瓜和核桃3种作物果实中硒元素富集;富硒土壤中硒的来源与区域地层中页岩、泥岩及上游铁矿相关,推测上述岩石经风化成土及后期水流搬运至黏土及砂质黏土区域被土壤黏土吸附沉积形成富硒区。

To evaluate the bioavailability of selenium in selenium-rich soil of Yinan,Shandong Province in different crops,and to speculate its source,soil,plant,and rock samples were collected accordingly from the research area,then the total selenium content in each sample and the content of five forms of selenium in water-soluble,weak acid extracted,reducible,oxidizable,and residual states were tested by ICP-MS,and the results were compared and analyzed.The results showed that:the total selenium content in soil is significantly constrained by spatial location and water system constraints;The effective selenium content is positively correlated with the total selenium content,and the spatial distribution is consistent;The total selenium content in soil is positively correlated with the nitrogen and phosphorus content;The main form of selenium in soil is selenite.The fruits of three crops,peanuts,walnuts,and watermelons,grew on selenium-rich soil in the research area are enriched with selenium element.The selenium source in selenium-rich soil is related to shale,mudstone,and upstream iron ore in the regional strata,and it is speculated that the above rocks were weathered into soil and later transported to the clay and sandy clay areas by water flow,where they were adsorbed and deposited by soil clays to form selenium-rich areas.