1. Alonso, Ε. 1997. Influencia de los parámetros edáficos en la retención de metales pesados en suelos afectados por hidromorfUa. PhD thesis. Department of Pedology. Com-plutensian University of Madrid, 280 pp.
2. European Economic Community. 1986. 86/278/CEE.European Community Official Journal, 186/6—12.
3. Förstner, U.W., Calmano, K., Conrad, H., Jaksch, H., Schimkus, C. and Schoer, J. 1981. Chemical speciation of heavy metals in solid waste materials (sewage sludge, mining wastes, dredged materials, polluted sediments) by sequential extraction.Proc. Int. Conf. Heavy Metals Environ, WHO/EED, 698—704.
4. ISRIC. 1993. Procedures for soil analysis. Wageningen. The Netherlands.
5. McBride, M.B. 1991. Processes of heavy and transition metal sorption by soil minerals. In: G.H. Boltet al. (eds).Interactions at the soil eolloid-soil solution interfaee, pp. 149— 175. Kluwer Academic Publ., Dordrecht, The Netherlands.