Multi-isotopic methods applied to monitoring groundwater nitrate attenuation in a regional system: Plana de Vic(Osona, NE Spain)

摘要

The presence of nitrate in groundwater of the Osona area is derived from the intensive cattle raising. Eventhough local administration regulates and controls the present use and distribution of manure as fer tilizer,according to legal application rates, nitrate pollution in Osona shows the effect of decades of uncontrolledmanure application. Vitòria (2004) using stable isotopes determined the presence of denitrification processes(natural attenuation of nitrate pollution) in a small area located in the Osona province. The main goal ofthis still on-going research (2005-2006) is to determine the extent of denitrification at a regional scale, andthe processes that control natural attenuation, using multi-isotopic methods (dD, d18O, T, d34S, d15N, d13C).Results show that denitrification is active in two areas, and that this process is linked to pyrite oxidation. Inthe studied area, data do not allow to identify the role of or ganic matter oxidation in denitrification. Theobserved denitrification processes reveal optional strategies for nitrogen attenuation