HIGH METAL FLUXES FROM A MAJOR MINING PROVINCE TO OCEAN THROUGH ACIDIC RIVERS (RIO-TINTO, SPAIN)

The South Iberian Pyritic Belt comprises the largest massive sulfide d eposits in the world. The biggest (Rio Tinto) has been outcropping for millions of years and has been worked for thousands of years (by Phoe nicians and Romans for example). This area is drained by the Rivers Od iel and Tinto which are highly acidic (pH 2) and carry very high metal fluxes down to their common estuary. Part of the metallic load is dep osited in estuarine sediments which display high trace-metal concentra tions. However, a significant fraction of this metallic load may escap e the estuarine zone. This can explain the trace-metal enrichments obs erved in the continental shelf waters of the Gulf of Cadiz and contrib ute significantly to trace-metal fluxes to the Mediterranean Sea throu gh the Strait of Gibraltar.