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(T/MF146) Partitioning of heavy metals in the sediments of Algeciras Bay (Spain). Usero, José1, Morillo, José1, Gracia, Ignacio1, 1 ABSTRACT- Algeciras Bay is located in the province of Cadiz in the most western part of the Mediterranean coast. In this bay there are large amounts of pollutant waste, most of which comes from large cities (Algeciras, La Linea de la Concepcion and Gibraltar) and their industrial area, one of the biggest in Andalusia. As metal sediments are distributed among a variety of physico-chemical forms which exhibit different chemical reactivities, the measurement of the total concentration of a particular metal is not sufficient to determine their possible remobilization. Thus, the chemical form of the metals in the sediment is of great significance in determining their behaviour in the environment and their remobilization potential. In this study, the distribution of eight metals (Cu, Zn, Cr, Pb, Fe, Ni, Co, Mn) among five phases (exchangeable, bound to carbonates, bound to reducible metal oxides of Fe and Mn, bound to organics and sulphide, and inert fraction) was determined in 12 sediments samples. The results obtained show that there are significant differences in the distribution of the elements analysed in the different phases. The high percentages of Zn, Mn and Pb in the first and second fractions are significant because the metals in these phases are those with a greater risk of remobilization into water. The element with the highest content in the third fraction is Co (32 %). Copper is the metal with the highest proportion bound to organics and sulphide (42%), probably due the great tendency for organic matter to complex with it. Finally, the percentage of metal present in the inert fraction is very high for Cr and Fe (67% and 92%, respectively). Key words: sediment, metal partitioning, metal pollution |
