TEMPORAL MERCURY DYNA MICS THROUGHOUT THE RICE CULTIVATION CYCLE: AN INTEGRATIVE APPROACH

Abstract

During the last few decades, the input of mercury to the environment resulting from anthropogenic activities has increased. This can translate into effects to both wildlife and humans. For the last fifty years, a chlor-alkali plant situated at the locality of Flix (NE Spain), ca. 100 km above the Ebro river mouth, has dumped mercury- loaded residues into the river. The residues have been transported throughout the river reaching its delta ecosystems (e.g., rice fields, flood plains, marshes, lagoons). The Ebro Delta (ca. 30000 ha of wetlands) is a highly important site of rice production with more than 75% of its area intended to this activity. Moreover, it constitutes one of the largest wetlands of the Mediterranean being also relevant from the conservation point of view, as it is the breeding habitat for several bird species. Rice paddies are considered a potential ‘hotspot’ for methylmercury due to the biotic methylation activities of soils, as well as a source of methylmercury for both aquatic and terrestrial food webs.