Classification of natural mineral and spring bottled waters of Portugal using Principal Component Analysis Carla Lourenço a, ⁎, Luís Ribeiro b , José Cruz c a National Laboratory of Energy and Geology (LNEG), Estrada da Portela Zambujal, Apartado 7586, 2721-866 Amadora, Portugal b CVRM Geosystems Centre, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal c General Direction of Energy and Geology, Av. 5 de Outubro, no 87, 1069-039 Lisboa, Portugal abstract article info Article history: Received 23 October 2009 Accepted 7 August 2010 Available online 14 August 2010 Keywords: Spring water Mineral water Hydrochemistry Principal Component Analysis Portugal Considering its area, Portugal is one of the world's richest countries in mineral and spring waters. There are 33 different types of bottled water, 18 of which are classified as natural mineral water and the remaining as spring water. The majority of these waters are of low mineralisation in comparison to most European bottled waters. Principal component analysis was used to identify the main geotectonic interrelationships among physico- chemical parameters, enhancing similarities and dissimilarities, and contributing to a new typology of bottled waters, based on their hydrochemical characteristics and geological occurrence. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Portugal, according to its size, population and geological diversity, is one of the richest countries in the World with respect to the number and variety of natural springs, some of which with proven medicinal properties that were known since ancient times (Lepierre, 1930). About 400 springs are known in Portugal: - springs classified as natural mineral water by a legislative Act before the Decree-Law of 1990 (Decree 15401 of 1928) and - springs with exceptional physico-chemical properties, which have been verified by specialists or their therapeutic qualities have been known over a long time. Natural mineral water, recognised as exceptional water, is not subject to maximum admissible values. Nevertheless, some reference values do exist and are defined by the EU Directive 2009/54/EC. In the case of natural spring water (as well as water for human consump- tion) the levels of physico-chemical parameters are established by the Decree-Law 243/2001. Natural mineral water has qualities that distinguish it from other natural water, such as the level of physico-chemical parameters. Although nature does not “produce” two natural waters with exactly the same chemical composition, it is, however, possible to group them into classes or types, based on some similarities of their physico- chemical properties. Overall, natural mineral and spring waters in Portugal are in general low mineralisation waters, a fact that is unlike the majority of bottled waters sold in other European countries, thus, revealing the taste of the Portuguese for this type of waters. From the marketing point of view, mineral and spring waters are outstanding economic valuable natural resources, representing a non negligible income for the regions where they occurred through bottling industries, with significant impact on tourism. Bottled natural mineral waters contributed with 203 million € (2008) to the Portuguese economy, and spring waters with 58.4 million € according to the statistics of DGEG — Direcção-Geral de Energia e Geologia (General Directorate of Energy and Geology). Water is essential to life support systems, and with the impact of climate change and anthropogenic activities to water resources, quantity and quality are becoming more rare and valuable for water resources. Hence, the importance to conserve and protect this natural resource. In the natural mineral water industry the tolerance, with respect to the deviation of physico-chemical and microbiological qualities, is actually very small. For this reason, there is a growing need to develop robust methodologies for water quality assessment to support decision makers in elaborating water management plans at national and municipal levels. Several statistical studies have already been carried out to analyze in more detail some important hydrothermal water resources of Portugal. Special emphasis was given to the use of the Mann–Kendall test to evaluate trends in water quality parameters in Pedras Salgadas and Vidago waters (Ribeiro and Lourenço, 1999; Lourenço and Ribeiro, 2007), and the application of multivariate statistics analyses Journal of Geochemical Exploration 107 (2010) 362–372 ⁎ Corresponding author. E-mail addresses: carla.lourenco@ineti.pt (C. Lourenço), luis.ribeiro@ist.utl.pt (L. Ribeiro), jose.cruz@dgge.pt (J. Cruz). 0375-6742/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.gexplo.2010.08.001 Contents lists available at ScienceDirect Journal of Geochemical Exploration journal homepage: www.elsevier.com/locate/jgeoexp