Diffuse pollution of water resources from agricultural sources is a major environmental issue in Europe. The nutrients released in groundwater from cultivated fields and livestock production, together with pesticides, are the main source of concern in the framework of the European Nitrates Directive (91/676/EEC). Southern Romania continues to represent one of the most important cereal production areas of the country. The intensive exploitation during the communist period continues to have repercussions for the precarious quality of groundwater. The aim of our study was to establish the environmental conditions, quantify the agricultural activities at the local administrative unit level and afterwards, to highlight areas of susceptibility to nitrate pollution of groundwater within the Oltenia Plain. One of the most efficient methods to evaluate human influences by agricultural activities on groundwater is using different types of indicators, such as land use indicators (cultivated surfaces), animal husbandry indicators (livestock and great beef units), and agri-environmental indicators (use of fertilisers based on nitrogen and phosphorus, quantity/ha). Throughout the paper, GIS methods are used to determine the degree of influence on nitrate pollution of several eco-pedological indicators: soil types and subtypes, slope of the land, soil texture, soil permeability, and groundwater level. Statistics indicate that 85% of the study area is susceptible to nitrate pollution from agriculture. Indicators provide information that can be easily interpreted by decision and policy makers, and they facilitate the process of reducing nitrate pollution. This study shows that the correlation of statistics and GIS modelling is a useful method for guiding prevention practices for groundwater pollution at the regional scale in Southwestern Romania.
Keywords: Agricultural activities; Geo-statistics; Groundwater; Nitrate pollution; Oltenia Plain; Susceptibility.