典型土壤环境中硒的迁移转化影响因素研究——以四川省成都经济区为例

Factors controlling the transport and transformation of selenium in typical soil environments: a case study of the Chengdu economic zone in Sichuan Province

硒作为人体健康生长必需微量元素,由于其显著的抗癌作用,开始受到越来越多人的关注,并因此产生了很大的经济效益。土壤中含硒量不足或过多以及存在的形态,直接影响到植物的生长状况和含硒量,又进一步通过食物链而影响人、畜的健康,因此研究土壤剖面中硒的迁移转化具有重要意义。笔者在四川省成都经济区按照不同的土壤类型采集了4条土壤剖面PM2、PM8、PM9、PM11,测试了土壤中全量硒和有效硒的含量,并通过土壤溶液的培养分别获得了土壤溶液及残渣土壤中全量硒、有效硒的含量,由此计算了土壤溶液中硒的分配系数(Ki=Ci残渣土壤/Ci土壤溶液)。结果显示,全量硒和有效硒含量在剖面的表层明显富集;有效硒含量与土壤全量硒呈显著的正相关关系,与土壤有机质含量呈正相关关系;不同类型土壤中硒的分配系数在剖面中均呈现出由深层到表层逐渐富集的规律,且与土壤中pH值和有机质含量呈现正相关关系。研究表明,不同类型土壤中Se向植物中的迁移转化主要受Se全量、土壤pH值、有机质及土壤粘粒影响,且Se随土壤溶液在垂向上的迁移不明显。

Selenium is an essential trace element which is beneficial for people＇s health and has significant cancer-fighting properties.More and more people have attached importance to this element,which has produced great economic efficiency.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant growth directly and then bring about further influence on the health of human beings and animals by food-chain.So It＇s significant to study the transport and transformation of selenium in the soil profile.In this paper,4 soil profile samples of PM2,PM8,PM9,PM11 were collected from Chengdu economic zone in Sichuan Province according to different soil types.The authors analyzed the content of total selenium and the available selenium content in the soil profiles.By cultivating soil solution the authors also obtained the total selenium and the available selenium content both in soil solution and in soil debris.Then the authors calculated the distribution coefficient of selenium in the soil solution.The result indicates that the total selenium and available selenium were well concentrated at the surface of these four soil profiles.The content of available selenium shows a significantly positive correlation with the total selenium and a positive correlation with the soil organic matter.By calculating the distribution coefficient of selenium（Ki） in different types of soil,the authors have reached the conclusion that the distribution coefficient of selenium is gradually concentrated from deep to top soil.Furthermore,the coefficient of selenium also shows a positive correlation with soil pH and the soil organic matter.This study also suggests that the total selenium,the soil pH,the soil organic matter and the clay fraction are the main factors affecting the transport and transformation of selenium to plant in different types of soils.The transport of selenium with the migration of the soil solution in the vertical soil profiles is not obvious.