DBPapers
DOI: 10.5593/SGEM2014/B51/S20.011

ASSESSMENT OF ARSENIC AND HEAVY METALS POLLUTION IN STREAM SEDIMENTS AFFECTED BY MINING USING GEOACCUMULATION INDEX

P. Favas, S. Sarkar
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-17-9 / ISSN 1314-2704, June 19-25, 2014, Book 5, Vol. 1, 73-80 pp

ABSTRACT
The objectives of this study were to determine the total concentrations of heavy metals and arsenic in stream sediments contaminated by a tin-tungsten mining operation (Vale das Gatas old mine, northern Portugal) and quantify the impact of the mining activity on the quality of sediments. In this study, a possible sediment enrichment of metals was evaluated in terms of the “index of geoaccumulation” (Igeo) values. This quantitative measure of metal pollution in sediments allows for the classification of the quality of sediments, from “unpolluted” (class 0) to “very highly polluted” (class 6). In this study, the geochemical stream sediment data highlight some anomalies associated with the old mine influence. Given the variations in total concentrations of trace elements along the stream and the Igeo values, it was possible to distinguish three individual sectors: 1) the sector upstream of mines and tailings was characterized by values corresponding to class 0 (non-polluted sediments) for almost all elements investigated; 2) the sector under the influence of the mines, but upstream of tailings showed a marked increase in the levels of Zn, Cu, Cd, As and Pb due to acid drainages from mines; 3) the sector downstream of tailings was characterized by a marked increase in Zn, Cu, Cd, As and Pb. The index of geoaccumulation values confirms that the sectors in the mine area and downstream the tailings are the most polluted, mainly with Cd, Cu, Pb and As.

Keywords: Abandoned mine, Acid Mine Drainage, Tailings, Vale das Gatas mine