Definition of a model for monitoring the chemical and chemical- physical characteristics of deep drinking waters

Thirty two parameters were studied and 761 sources were examined (549 springs and 212 wells). Factor analysis applied to several parameters indicated ten factors, but the first three had the greatest share of variance. In the first factor the most important parameters are: calcium, hardness (total, temporary and permanent), solid residue, electric conductivity, pH, sulfates and magnesium. In the second: turbidity, suspended substances and aluminium, and in the third potassium and phosphates. The cluster analysis applied to these parameters confirmed the relationships found by factor analysis except for the pH in the first group and aluminium in the third one. These associations are consistent with the criteria suggested by the Italian law and by the EEC Directive for checking drinking water. Another cluster analysis, applied to several drinking water sources, grouped the samples in three clusters: the characteristic hills of the Umbrian region and in the valleys of the principal rivers; the mountains of the Apennines and where the river Tiber valley joins the Umbria valley. The application of these multivariant analysis methods for characterizing the deep waters confirms their usefulness in evaluating the chemical and chemical-physical characters and the possible modifications to these. -from Authors