珠江三角洲台山地区硒的地球化学特征

Geochemical Characteristics of Selenium in Taishan Region of Pearl River Delta

通过对台山地区岩石、土壤、农作物等样品的系统采集,准确测定了它们的硒含量,研究该地区硒的地球化学特征,探讨土壤富硒来源,查明当地富硒农产品的开发利用前景。结果表明,台山地区岩石均含有硒,但含硒量与岩石的岩性及形成的时代密切相关,而在各时代形成的岩石中,上寒武统浅变质水石组岩石含硒量最高。不同岩性含硒量的分布规律为浅变质泥岩→泥质粉砂岩→凝灰岩→花岗岩。台山地区表层土壤硒含量较高,但不同成土母质土壤剖面的硒含量分布存在明显差异,浅变质泥岩母质类剖面硒分布以底部聚积形式显现,砂岩母质类呈表聚现象,花岗岩母质类则以中部淀积层富集为特征。岩浆活动的硒源提供、区域浅变质作用的活化富集及粘土矿物的吸附保留,它们共同作用造成了台山地区土壤丰富的硒含量。在不加入外源硒及未经土壤改良的情况下,台山地区超过40%的农作物硒含量已达到现有的富硒农产品含量标准要求,具有广阔的开发富硒农产品前景。

Taishan region is located in the southwest of Pearl River Delta,Guangdong Province.Through differ-ent types of rocks,soils and crops were systematically sampled;geochemical characteristic of selenium,source of selenium in soils,and prospects of selenium-enriched agricultural products in this area were studied.The re-sults show that the selenium contents is closely related to lithology and strata,and that content in the Upper Cambrian Shuishi Formation is the highest.The content level of lithology is in the order of epimetamorphic mud-stone,argillaceous siltstone,tuff,granite.There are abundant selenium with the surface soil in the area,but distribution of selenium in different parent materials soil profile was significantly different.Selenium in soil pro-file of epimetamorphic mudstone parent materials was enriched in the bottom,but the sandstone occurred in top-soil layer,while the granite parent materials occurred in the middle illuvial horizon.Magmatism selenium provi-ding,the regional shallow metamorphism activation and enrichment,and clay mineral adsorption cause rich se-lenium contents in soils in Taishan region.Neither the addition of exogenous selenium nor soil improvement,the selenium contents of corps in the area for more than 40% has reached the requirements for selenium-enriched contents standard of agricultural products,indicating an alluring prospects for the development of selenium-en-riched agricultural products.