Chemometric Analysis and Mapping of Environmental Pollution Sources in the Ebro River Basin

Abstract

Principal component analysis (PCA) and multivariate curve resolution alternating least squares (MCR-ALS) are shown to be powerful chemometric methods for the analysis of environmental monitoring data sets. They allow for the investigation, resolution, identification, and description of pollution patterns distributed over a particular geographical area, time, and environmental compartment. Historical data of the Ebro River basin available from the Confederación Hidrográfica del Ebro (CHE), which is the organization in charge of the basin, covering different years since 1992 for different environmental compartments were investigated to assess the contamination sources affecting the river basin. For ongoing contamination, data sets obtained from a 3-year extensive monitoring study (from 2004 to 2006) were analyzed. Agricultural practices were identified as the main source of surface and groundwater diffuse pollution, while sediments and soils appeared mostly polluted by a contamination pattern mainly loaded by polycyclic aromatic hydrocarbons (PAHs) of possible pyrolitic origin. Another pollution pattern related to past and ongoing industrial activities was detected to be principally stored in the sediment compartment. Moreover, a pollution source resulting from rice-related agricultural practices was identified in the Ebro River delta, with its highest levels detected in May, coinciding with pesticides application during the earlier stages of the rice cycle.

Graphical Abstract