Capítulo 17 Chemical elements in superficial sediment CAPÍTULO 17 CHEMICAL ELEMENTS IN SUPERFICIAL SEDIMENTS OF FIVE RESERVOIRS IN THE CATALONIA AND ARAGON REGIONS (SPAIN): IS THERE AN ANTHROPOGENIC CONTRIBUTION? Marcelo Pompêo1, Joan Pere Casas Ruiz2, Viviane Moschini-Carlos3, Rafael Marcé4, Paula Yuri Nishimura1, Joan Armengol2, Pilar López2 1 University of São Paulo, Institute of Biology, Department of Ecology, São Paulo, Brazil 2 University of Barcelona, Department of Ecology, Barcelona, Spain 3 State University of São Paulo (UNESP), Sorocaba Campus, Sorocaba, Brazil 4 Catalan Institute for Water Research (ICRA), Girona, Spain E-mail:
[email protected] ABSTRACT Evaluation was made of the sediments of five Spanish reservoirs, four in the Catalonia region (the Sau, Susqueda, Foix, and Santa Fe reservoirs), and one in the Aragon region (the Barasona reservoir). The sediments were collected in 2011. At the Barasona, Sau, and Foix reservoirs, the sediments were obtained at three sites, one in the upper region of the reservoir, at the entrance of the main river, one in the zone near the dam, and another in the central region, between the river and dam regions. At the Santa Fe and Susqueda reservoirs, the sediments were obtained only near the dam. The superficial sediment was sampled with a 400 cm2 Lenz type dredge. In the laboratory, the sediment samples were dried at 60 oC and ground in a glass mortar. The concentrations of different chemical species were determined by X-ray fluorescence and by a microwave digestion procedure (using Teflon bottles with HCl and HNO3). Measurements were made of the following species: Al2O3, P2O5, K2O, CaO, SiO2, TiO2, MnO, Fe2O3, MgO, Na2O, Ag, As, Ba, Br, Cd, Ce, Co, Cr, Cs, Cu, Ga, Hf, I, La, Mo, Nb, Nd, Ni, Pb, Rb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Te, Th, Tl, U, V, W, Y, Yb, Zn, and Zr.