Heavy metals at the Guadalquivir estuary

Abstract

Temporal surveys at the Guadalquivir estuary were carried out between May and December 1998 to assess the behaviour of four heavy metals (Zn, Cd, Pb and Cu). These metals presented a non-conservative behaviour, with KD ranging between 102 and 104. Losses related to the dissolved phase have been quantified, as well as their metal speciation. The concentration of heavy metals associated with different geochemical fractions in sediments was also determined. Each metal showed a different distribution depending on whether its origin was associated (Zn and Cd) or not (Pb and Cu) to the toxic mud from Aznalcóllar. In general, heavy metal (Zn and Cd) enrichment was found in the estuary (due to the Aznalcóllar mining spill), determined in their concentrations in the most bioavailable fractions of the sediment.