Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy).

In the European Union, nitrate vulnerable zone (NVZ) should be designed for the mitigation of nitrate (NO) contamination caused by agricultural practices. Before establishing new NVZ, the sources of NO must be recognized. A geochemical and multiple stable isotopes approach (hydrogen, oxygen, nitrogen, sulfur and boron) and statistical tools were applied to define the geochemical characteristics of groundwater (60 samples), calculate the local NO threshold and assess potential sources of NO contamination in two study areas (hereafter Northern and Southern), located in a Mediterranean environment (Sardinia, Italy).