The Donana ecological disaster: Contamination of a world heritage estuarine marsh ecosystem with acidified pyrite mine waste

One of the most important bird breeding and over wintering sites in the wes t of Europe, the Coto Donana, was severely impacted by the release of 5 mil lion cubic meters of acid waste from the processing of pyrite ore. The wast e entered ecologically sensitive areas of the park (including breeding area s for internationally endangered bird species) causing sustained pH decreas es from pH 8.5 to 4.5 and resulting in massive metal contamination of the i mpacted ecosystem. The contaminating sludge waste contained arsenic at 0.6% , lead at 1.2% and zinc at 0.8% on a dry weight basis. The acid conditions facilitated the solubilization of these metals, leading to water concentrat ions lethal for aquatic wildlife. The accident caused considerable fish and invertebrate kills and has severe consequences for the protected bird spec ies dependent on the impacted habitats and adjacent areas. (C) 1998 Elsevie r Science B.V. All rights reserved.