Heavy metals and As transport under low and high flows in the River Guadiamar three years after the Aznalcóllar tailings dam failure : implications for river recovery and management

Abstract

This paper presents work from an on-going research programme examining the recovery of the Guadiamar River following the April 1998 Aznalcóllar tailings dam failure. Analysis of heavy metal (Cd, Cu, Pb and Zn)

River Systems and Environmental Change

“…As elsewhere in the Mediterranean, while phases of large-scale Late Pleistocene river aggradation in the Bergantes Valley are correlated with Heinrich events and with stades of the Dansgaard-Oeschger cycles (Macklin et al 2002), the record of river response to sub-orbital-scale climate change is more complex and spatially variable. In the tectonically quiescent Mediterranean regions of North Africa and the Iberian Peninsula, environmental changes were characterized primarily by reorganizations within the fluvial sediment system-the most notable of which were major fluctuations in tributary stream sediment delivery, and changes in alluvial storage within high-order valleys.…”

“…In order to identify and understand both the processes that govern river behaviour and causality relationships in fluvial systems, it is essential that alluvial units are reliably dated. Increasingly robust fluvial geochronologies based on radiometric dating methods such as luminescence and uranium series are now available for a growing number of Mediterranean river basins and these techniques have led to new insights into Middle and Late Pleistocene river behaviour (Macklin et al 2002;Woodward et al 2008). In addition, the development of accelerator mass spectrometry has revolutionized the dating of terminal Pleistocene and Holocene age fluvial deposits by the virtue of being able to date very small samples of organic material that could not have been dated using conventional radiocarbon dating methods (Woodward et al 2001;Thorndycraft and Benito 2006).…”

“…This has produced a rapidly expanding database of radiometrically dated Late Glacial and Holocene fluvial units that, in conjunction with new high-resolution proxy climate records, have enabled the relationship between river behaviour and climate change to be documented and interrogated in increasing detail over both space and time (e.g. Abbott and Valestro 1995;Woodward et al 2001;Macklin et al 2002;Thorndycraft and Benito 2006;Zielhofer et al 2004).…”

“…The widespread occurrence of glacial landforms and sediments in the headwaters of many Mediterranean river basins has been known for well over a century (Cvijić 1900;Niculescu 1915;Almagià 1918; Chapter 12). However, outside north-east Spain (Pyrenees; Sancho et al 2003), north-west Slovenia (South Julian Alps; Bavec et al 2004) and, most notably, the Voidomatis River basin in the Pindus Mountains of northwest Greece (Bailey et al 1990;Lewin et al 1991;Woodward et al 1992Woodward et al , 1995Woodward et al 2001Macklin et al 1997Macklin et al , 2002Hamlin 2000;Hamlin et al 2000;Woodward et al 2008), the downstream impact of this glacial activity upon Pleistocene river development is still relatively poorly known.…”

Mine tailings dams: Characteristics, failure, environmental impacts, and remediation

“…Following the Aznalcóllar-Los Frailes spill, emergency removal of the tailings from the Ríos Agrio and Guadiamar began on May 3, 1998, continuing to December of that year, during which 4.7 million m 3 of contaminated soil and vegetation was removed to the Los Frailes open pit (Grimalt et al, 1999;Hudson-Edwards et al, 2003). A second phase of cleanup took place during the summer of 1999 which removed a further 1 million m 3 of material to the pit (Eriksson and Adamek, 2000;Turner et al, 2002). These actions, and the walls that were constructed at Entremuros, considerably reduced the medium-and longterm impacts on wildlife in the catchment (Hudson-Edwards et al, 2003).…”