『Abstract
　The purpose of this study is to show the results of the Italian research project of national interest (PRIN) launched in 2006 and finished in 2008, concerning the “assessment of groundwater contamination risk by nitrates assessment”. The project verified the IPNOA method for nitrate groundwater contamination risk assessment in four test-sites of Italy. The IPNOA is a parametric index which assesses the potential hazard of nitrate contamination originating from agriculture on a regional scale. The method integrates two categories of parameters: the hazard factors (HF), which represent all farming activities that cause, or might cause, an impact on soil quality in terms f nitrate (use of fertilisers, application of livestock and poultry manure, food industry wastewater and urban sludge), and the control factors (CF) which adapt the hazard factors to the characteristics of the site (geographical location, climate conditions and agronomic practices). Finally, the Potential Risk Map is obtained by coupling the potential hazard of nitrate pollution (IPNOA) and the aquifer Contamination Vulnerability Map. The project was carried out by five Research Units (RU) from the Politecnico di torino, Universities of Piacenza, Florence, Naples and Palermo. The geochemistry of groundwaters from the four test-sites was studied to determine the distribution of nitrate, and to evaluate groundwater chemical facies. All the study areas are affected by groundwater nitrate contamination and often by hydrogeochemical peculiarities. In some cases isotopic study, δ¹⁸O-NO3, δ¹⁵N-NO3, allowed to differentiate nitrates of chemical fertilisers from those of biological origin, as well as denitrification processes.

Keywords: Groundwater contamination; Nitrate; Groundwater vulnerability; Risk assessment; Italy』

1. Introduction
2. Methods
　2.1. The model SINTACS R5 for the assessment of aquifer contamination vulnerability
　2.2. The agricultural nitrate hazard index: IPNOA
　　2.2.1. IPNOA calculation
　　2.2.2. Considerations about the IPNOA method
　2.3. The index of hazard from nitrates of household origin: IPNOC
3. Potential nitrate risk of contamination of a plain in the province of Cuneo (NW Italy)
　3.1. The Fossano area
　3.2. Considerations on the potential nitrate risk map of the Fossano area
4. Pollution risk for groundwater from nitrates of agricultural and household origin in the Cecina Plain (Tuscany, central Italy)
　4.1. Evaluation of the groundwater pollution risk in the Cecina Plain
　4.2. Water geochemistry and isotopic composition of nitrate in the Cecina Plain
5. Nitrate contamination risk mapping and influence of the hydrogeochemical pattern in the northern part of the Volturno River Plain
　5.1. Hydrogeology and hydrogeochemistry of the northern part of the Volturno River Plain
　5.2. Nitrate groundwater contamination risk assessment using the IPNOA method in the northern part of the Volturno River Plain
6. Hydrogeological resources, hydrogeochemistry and groundwater nitrate contamination risk assessment of the Ribera test site (Sicily, Italy)
　6.1. Geochemical context of the Ribera test site
　6.2. The map of intrinsic nitrate contamination risk from agricultural sources at the Ribera test site
7. Conclusions
References