June 18, 2009

Heavy metals found in Spanish estuary

Spanish scientists say they've confirmed the presence of zinc, copper and lead at high levels in the Huelva estuary's water and sediments in southwest Spain.

The team of researchers from the University of Cadiz also studied how some of the heavy metals are transferred to fish and discovered zinc, cadmium and copper accumulate in the body tissues of sole and gilthead bream.

We found positive correlations between the levels of some metals in the waters of the Huelva estuary and those in the tissues of gilthead bream (Sparus aurata) and sole (Solea senegalensis), Professor Dolores Galindo said.

Numerous laboratory studies have looked at the effects of pollutants on aquatic organisms, Galindo said. But our research observes this phenomenon in the natural environment, in one of the few estuaries in Spain with high levels of metals contamination.

The Huelva estuary and the Tinto and Odiel rivers that flow into it are all affected by discharges from industries and historic mining activities. The area, in which fishing is forbidden, is globally significant in terms of its levels of heavy metal contamination.

The scientists reported their findings in a recent issue of the Journal of Hazardous Materials.