Abstract
Hazardous wastes of industrial and domestic origin are becoming one of the most serious problems in industrialized areas. Groundwater contamination is the main result of waste dumping and accumulation. The Besós River Basin (Barcelona) has supported rapidly growing chemical, metallurgical and textile industries that have damaged the quality of the water supply. Hydrochemical effects of these different contamination foci on water quality are very similar. Principal Component Analysis was used on the raw data to bring out the subtle variations between the different sources of contamination, locating and discriminating these foci, even the unknown ones.