Metal partitioning and pH-buffering during mixing processes in an estuary strongly affected by acid mine drainage - The Ria de Huelva estuary (SW Spain)

摘要

The acidic and metal rich waters of the Odiel and Tinto rivers flow into the Huelva Estuary (SW Spain), where mixing with seawater take place. During these mixing processes intense precipitation of Fe and Al in the fluvial domain of the estuary is observed. Hence, a buffer at pH ranges between 3 and 5.5 is observed, although the spatial location of these buffers is determined by river water/seawater ratio and tides. The information provided by this study is essential to trace the metal fate from rivers affected by AMD to the ocean, particularly to the Gulf of Cadiz and the Mediterranean Sea, which are enriched in metals compared to other seawaters worldwide.