3-way principal component analysis applied to the evaluation of water quality of underground waters in the area of Siracusa

The present work reports the results of evaluation of the water quality of underground waters in the area of Siracusa (Sicily). Due to the high densit y of industries, this area has been considered a high hazard site for the e nvironment. The area under study is located in the Southeast of the Ionic c oast of Sicily, and extends for about 20 Km inland. In this site, 487 sampl es of groundwater were collected during 1994. The study has been focused on the chemical-physical characteristics of the waters and on the space-time relationships pointed out in the data by the application of 3-way Principal Component Analysis. This method has been applied in addition to the classi cal multivariate analysis techniques, in order to study the three-dimension al data structure which is typical of environmental studies (samples x vari ables x sampling times). The further information obtained on the similarity of underground waters can be very useful for the improvement of criteria o f water resource management in Sicily.