The contamination from nitrate in waters: application of a isotope model in the regions of the Po Basin, the Venetian Plain and Friuli Venezia Giulia
On the basis of the agreement of the State-Regions of 5 May 2011, it was signed in 2012 the Convention MIPAAF- ISPRA, aimed at improving the level of knowledge about the origin of the content of nitrates in groundwater and surface water present in the regions of the Po basin, Venetian plan and Friuli Venezia Giulia. The approach adopted under the Convention MIPAAF-ISPRA took as reference parametric indicators, and the use of isotopic investigations to quantify experimentally the contributions of the different sources in areas affected by multiple sources at monitoring points of observational networks of reference for the national system, SINTAI, and for the European, EioNet.
In the first phase of the Convention, ISPRA together with the five Regions involved, Piemonte, Lombardia, Emilia Romagna, Veneto e Friuli Venezia Giulia, has developed an index to HI municipal scale based on assigning scores to the sources, to the total load of nitrogen and site-specific features linked with parameters related to climate, soil, hydrological, anthropogenic and satellite with the use of layer high-resolution Imperviousness Degrees of land monitoring produced under the Copernicus program.
This index HI represents the danger of potential contamination of groundwater through the soil, and the physical, chemical and biological active in it, for the presence and the use of nitrates in the soil surface.
The second phase of the project ISONITRATE, the monitoring points identification of the origin of nitrates detected in the waters, started in parallel to the optimization activites of the model. The methodological approach, was developed by the project ISONITRATE, carried out by French Institute for geological Sciences (BRGM) in cooperation with other European institutions: each source of nitrates is characterized by different ranges of isotopic ratios of nitrogen molecules and thus the discrimination between the different sources is based on the relationship between the isotopic ratios in sources with those obtained in water.