Anomalías en REE como indicador de contaminación por vertidos de fosfoyesos en el estuario de los ríos Tinto y Odiel (SO de España)

Abstract

In two cores in the Odiel and Tinto river estuary, Sc, Y, Th and Cu concentrations show a significant increase in the intermediate levels, between 10 and 40 cm depth. Vertical evolution patterns for Sc, Y, Cu and heavy rare earth (HREE) are similar, and contrary to those shown by Th, light REE (LREE) and middle REE (MREE). Samples of the intermediate levels of the cores show significant enrichment of REE relative to North American Shale Composite (NASC) and high values in the (La/Gd)NASC and (La/Yb)NASC ratios. These anomalies in the fractionation patterns caused by enrichments in LREE and MREE concentrations are related to the presence of high concentrations of Th. They were generated by effluents from fertilizer factories between 1968 and 1998 which used phosphorite as source material