Atenuación de nitratos en el Humedal de Salburua (País Vasco). Contexto hidrogeológico

The Salburua wetland is located within a vulnerable zone (quaternary aquifer) related to the farming origin nitrate pollution. The restora - tion of the wetland, which was drained some decades ago, has evidenced the attenuation of nitrates in groundwater entering from farm - lands, which exceed 50 mg/l NO 3 - . The recently installation of piezometric network has allowed to characterize the groundwater flow pat - tern and determine the hydrogeological context of nitrate loss processes. Despite the dilution is happening the most important process seems to be the denitrification, either heterotrophic or autotrophic, probably depending on marly substratum position . The potential of denitrification has been measured in the soils and the values are really highs. This paper focuses on the right conditions for denitrifica - tion in the wetland.