F. Facchino (Dipartimento Scienze dell'Ambiente e del Territorio, University of Milano, Milano, Italy)

G. Giuliano (I.R.S.A. - C.N.R., Roma. Italy)

A procedure for assessing the pollution potential of pesticides for groundwater is proposed, which is suitable to be applied within a GIS environment. The approach integrates the climatic, geopedological and hydrogeological features of the site with the chemodynamic behaviour of the polluting substances. Since it deals with a non-point type pollution source, the assessment is referred to unit vertical profiles, each one including soil zone, unsaturated zone and aquifer. Vulnerability and potential contamination indices are obtained through a matrix combination of the ranked values of pesticides migration parameters, i.e. travel time, leaching quantity, aquifer dilution, expected contaminant concentration in groundwater. The areal distribution of the indices is represented in raster maps. The procedure is applied at the same scale of detail in two sample areas of northern Italy, in order to test its adaptability to different types of hydrogeological settings. An evaluation of the results is given with reference to the actual state of groundwater quality.