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尽管硒(Se)是一种重要的生命元素,但是即使浓度很低,也有可能会造成危害。在美国西部,包括犹他州中部GreenRiver流域斯图尔特湖水鸟管理区,大面积的农业排水区中都存在硒。为了对该场地进行地球化学研究和进行修复,取未受扰动的岩芯分析了硒的形态、浓度和迁移。用酸消解进行前处理对土壤和曼柯斯页岩风化壳进行了分析,结果表明,硒的最高浓度为3ppm,采用连续萃取法的分析结果表明,有19%~79%的硒是以有机物形式存在的,有17%~67%的硒是以元素形式存在的。柱实验研究结果表明,硒可以从深部土壤迅速淋出,可溶性硒的质量分数很高,达到了292×10-9。表层土壤中硒的淋出速度最初很慢,但是非常稳定,最终淋出速度会超过深部土壤。当对岩心通过放射灭菌后,表层土壤和深部土壤的淋出速度都会加快。计算结果表明,在修复富含硒的土壤时,所需的水量很大,每kg土壤需要约500L的水量。
Although selenium (Se) is an important element of life, it can be harmful even at low concentrations. Selenium is found in the western United States, including the Lake Stewart Waterfowl Management Area in the GreenRiver Valley in central Utah, and in large agricultural drainage areas. In order to conduct a geochemical study of the site and to repair it, the morphology, concentration and migration of selenium were analyzed for undisturbed cores. The results showed that the maximum concentration of selenium was 3ppm. The analysis by continuous extraction method showed that 19% ~ 79% of the selenium was in organic matter Form exists, 17% to 67% of the selenium is present as an element. The experimental results show that selenium can be quickly leached from the deep soil, the soluble fraction of selenium is very high, reaching 292 × 10-9. The leaching rate of selenium in the topsoil was initially very slow, but very stable, with the final leaching rate exceeding the depth of the soil. When the core is sterilized by radiation, the leaching rate of the surface soil and the deep soil is accelerated. Calculations show that the amount of water required to repair selenium-rich soils is very high, requiring about 500 liters of water per kg of soil.