关键词: 同步辐射, μ-XRF, 重金属, 污染土壤

Abstract: Synchrotron-radiation-based micro-beam X-ray fluorescence (μ-XRF) technology can be used to analyze in-situ elemental composition, chemical properties, and material structure of samples and bi-dimensional distribution of the elements in the samples, thus making it possible to intuitively observe distribution of target elements in a complex system. Using the traditional acid digestion in combination with the state-of-art μ-XRF technology, the contents and spatial distribution of metal (-loids) in a polluted soil were investigated. The soil was collected from a tin mining area in Hunan Province, China, which is one of the largest Sb mines in the world, and has long been famed as the “World Antimony Capital”. In addition, linear regression analysis was performed for relationships between elements in the soil. Results show that the soil was quite high in Sb and As, being 6 681 and 878 mg•kg^-1, respectively, in concentration. Moreover, μ-XRF revealed that As was closely related separately to Fe and Mn, in spatial distribution with determinant coefficient reaching 0.225 8 and 0.181 1, which more intuitively displayed that As in the soil was dominantly Fe-Mn-bound As. Comparing with the traditional acid digestion method, the μ-XRF method is able to intuitively expose in-situ relationships between the elements in distribution in the soil, so it is an useful tool in overall assessing and predicting environmental behaviors of heavy metals in the soil, which in turn provides theoretical support to the development of technologies to remedy polluted soils.

Key words: synchrotron radiation, μ-XRF, heavy metal, polluted soil