Heavy metal speciation of estuarine sediments affected by acid mine drainage in the Tinto and Odiel estuary, Spain. Relationship to bioconcentration of fish tissues

The concentrations of trace elements in sediment and fish samples from Ria of Huelva, located in SW Spain, were investigated. The Tinto and Odiel rivers (with highly acidic, pH 2.2-3.6) drain the Iberian Pyrite Belt, an important metal-rich sulphide deposit. The speciation of six elements (Fe, As, Zn, Cd, Pb and Cu) in four different fractions was performed by sequential extraction and the levels of heavy metals in fish were determined in muscle, gill and liver of two fishes, Solea senegalensis (sole) and Sparus aurata (gilthead) from Ria of Huelva. Results of the speciation analysis of sediments showed different distribution among studied metal. Cd and Zn were found associated mainly with soluble forms (exchangeable metals and metals bound to carbonates species), Cu and Pb appeared distributed among organic, inorganic and inert fraction, while As and Fe were associated mainly to inert fraction. The concentration of metal in fish showed differences between fish species and tissues with high accumulation of metals in liver and gill. Only As showed high accumulation in muscle. By means of results, it can be concluded that the human health risk due to heavy metals in fish from Ria of Huelva is high and is affected by the abiotic environment outstandingly. © by PSP 2008.