Abstract

Multivariate data analysis techniques were used to identify the interrelationships between the physical-chemical analyses of 22 parameters sampled monthly from 1991 to 2007 at 16 monitoring stations along the Elqui river and its tributaries to characterize the scale of the geogenic and anthropogenic impacts on the river's water quality. Principal component analysis was used to identify the differences and similarities between variables in the watershed. Factorial indices, computed to highlight the sections of the river and tributaries more influenced by hydrothermal, mining or agricultural activities, made it possible to synthesize groups of parameters with similar characteristics into a single value.