DETERMINATION OF THE POLLUTION LOAD TO THE SUBSOIL. From a theoretical point of view is required to establish four semi-independent characteristics of the pollution load to the subsoil (Foster, 1987), for each pollutant activity: to) the class of contaminant involved. (b) the intensity of the provision. (c) the mode of provision in the subsoil. (d) the application of the pollutant load time. Of the foregoing, has for the estimation of pollutant load into the subsoil, a value: 0.20.

DETERMINATION OF THE VULNERABILITY OF THE AQUIFER. As stated, the term aquifer pollution vulnerability is used to represent the intrinsic characteristics that determine the susceptibility of an aquifer to be adversely affected by a contaminant load. persistent, non-degradable, generated by a widely distributed polluting activity. In this case even the dilution of the aquifer capacity may not be effective to mitigate the pollution. * Additionally those aquifers that would be considered as less vulnerability to pollution, in general terms, tend to be more difficult to rehabilitate a contaminated time. In this sense, at least, they could be considered of high vulnerability to contamination. The components of vulnerability, mentioned above, are not directly measurable, but determined by various combinations of other factors. Taking into account that the selection of these parameters is based on those data probably available and easily collected, then the list is composed of: (a) the depth of the phreatic or roof of the confined aquifer.

(b) the type of occurrence of groundwater. (c) the characteristics, in terms of lithology and degree of consolidation strata above the saturated zone. These three parameters contain, even if it is in a qualitative sense, most of the required data. In the base to them applies an empirical methodology for the assessment of the vulnerability of aquifer that involves the indexation of these parameters in three discrete phases.