Resumo

TAVARES, M.T et al. Geochemical behavior of trace elements in the surroundings of Mina de S. Domingos, Alentejo: Tapada and Telheiro sites. Rev. de Ciências Agrárias [online]. 2009, vol.32, n.1, pp.182-194. ISSN 0871-018X.

Even thought the mining activity in S Domingos finished more than forty years ago, the mining site is still a source of polluting trace elements for soils and sediments downstream the open pit. The present work aims to evaluate the contamination of these soils and sediments. Therefore two sampling areas were selected: one, assumed as non-contaminated (Tapada), is used to access the reference values of the chemical variables for this region, and the other, downstream from the mining site, is affected by the mining activity (Telheiro). The soils and sediments were characterised on the <2 mm fraction, by pH (H2O), organic carbon and free iron oxides content. A total multi element analysis was done on the same fraction. Univariate and multivariate statistics were performed, as well as geochemical mapping using geostatistical interpolation methods. In Telheiro some samples had high levels of trace elements (mainly As, Pb, Sb, and Hg) and very low pH values (minimum 2.66), this is particularly obvious in the samples collected close to the acid mine drainage. In Tapada no contaminated soils were found. The multivariate analysis showed an association between As, Pb and Sb and between Cu and Zn

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