Uso da Análise Estatística Multivariada na Caracterização de Heterogeneidades Hidrogeoquímicas dos Sistemas Aquíferos, uma Revisão Metodológica

Use of Multivariate Statistical Analysis in the Characterization of Hydrogeochemical Heterogeneity of Aquifer Systems, a Methodological Review

Abstract

There is a growing concern regarding underground water resources, driving the development of more refined methods to assess changes in these resources, whether they arise from natural processes or direct and indirect interventions in the environment, of a physical or chemical nature. This study addresses the main techniques of the Multivariate Statistical Analysis (MSA) method applied to this purpose. MSA has been widely employed in characterizing aquifers and in studies related to contamination from mining activities, urban or rural interventions (agricultural and livestock), and in identifying processes of marine intrusion resulting in salinization. Additionally, this approach was used to segment the territory into areas with different qualities of groundwater. Forty articles were analyzed, with 80% of these originating from countries in Asia, Africa, and North America. During this evaluation, it was also possible to examine the relative applicability and complementarity of Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) to achieve the scientific objective, i.e., the investigation of natural and/or anthropogenic processes in groundwater. Both methods, when compared to conventional geochemical grouping or other multivariate statistical techniques, stood out as the most suitable and common in characterizing aquifer heterogeneities. We conclude that the applicability of this statistical approach is universal, as the employed techniques are independent of lithology type, as they are linked to the hydrogeochemical nuances addressed in the studies.Based on articles published between 1965 and 2022, it was possible to recognize in MSA tools a crucial instrument in the management and development of underground water resources, addressing both current and future demands.