Soils of Sao Domingos mine. REE chemical characterization

This work addresses the chemical features of topsoils from Sao Domingos mine, Portugal, an abandoned mining area since middle of twentieth century. The fractions below 1 mm of the surface-soil samples (0-15 cm) were measured by k0-standardized, instrumental neutron activation analysis in order to determine the levels of rare earth element concentrations in comparison to control soils. A fractionation between the heavy and light rare-earth elements (REEs) occurred, with the latter enriched relatively to the first ones. The REEs pattern is similar in all sites with higher concentrations in the mine area as compared to the control site. The ratios between REEs are conventional for three subsamples but slightly diverge for the other sites. The REEs pattern is similar to one of the volcanic islands still with activity as Sao Miguel in Azores, Portugal, and similar to the one of an industrial area containing coal power plant and refinery. (author)