Application of the fundamental parameter method to the assessment of major and trace elements in soil and sediments from Osamu Utsumi uranium mine by WDXRF

Abstract Wavelength dispersive X-ray fluorescence spectrometry (WDXRF) is a suitable technique for the characterization of contaminated mining sites, providing a quick and reliable screening for areas of significant contamination. This study established and validated a non-destructive methodology for quantitative simultaneous determination of major and minor constituents in soil and sediments by WDXRF, which was further applied to quantify soil and sediment samples from Osamu Utsumi uranium mine (Caldas, Minas Gerais, Brazil). Elements such as Ce, La, Nd, Mn and U were found in more concentrated levels in the calcium diuranate deposit (DUCA), whereas Fe and Al were found at higher levels in the soil samples corresponding to sites where accentuated leaching processes have occurred. Comparatively, the levels of U and rare-earth elements were found in significantly higher levels in the sediments retrieved from the mine’s pit as a result of acid mine drainage. These findings are believed to be useful as an initial environmental assessment for the decommissioning process of the mine.

摘要：波长色散X射线荧光光谱法（Wavelength Dispersive X-ray Fluorescence Spectrometry，WDXRF）是受污染矿区表征的适用技术，可对污染程度较高的区域开展快速且可靠的筛查。本研究建立并验证了一种采用WDXRF对土壤与沉积物中的常量及微量组分进行同步定量测定的无损分析方法，并将该方法应用于巴西米纳斯吉拉斯州卡尔达斯市Osamu Utsumi铀矿的土壤及沉积物样本的定量检测。研究结果显示，重铀酸钙（Calcium Diuranate，DUCA）沉积物中铈（Ce）、镧（La）、钕（Nd）、锰（Mn）与铀（U）等元素的浓度更高；而在发生显著淋滤作用的采样点土壤样本中，铁（Fe）与铝（Al）的浓度更高。相较而言，受酸性矿山排水影响的矿井坑内采集的沉积物中，铀与稀土元素的浓度显著更高。上述研究成果可作为该矿井退役流程中初始环境评估的有效参考依据。