title: The use of multicomponent statistical analysis in hydrogeological environmental research.
abstract: The present article examines the possibilities of investigating NO(3)(-) spread in aquifers by applying multicomponent statistical methods (factor, cluster and discriminant analysis) on hydrogeological, hydrochemical, and environmental parameters. A 4-R-Mode factor model determined from the analysis showed its useful role in investigating hydrogeological parameters affecting NO(3)(-) concentration, such as its dilution by upcoming groundwater of the recharge areas. The relationship between NO(3)(-) concentration and agricultural activities can be determined sufficiently by the first factor which relies on NO(3)(-) and SO(4)(2-) of the same origin-that of agricultural fertilizers. The other three factors of R-Mode analysis are not connected directly to the NO(3)(-) problem. They do however, by extracting the role of the unsaturated zone, show an interesting relationship between organic matter content, thickness and saturated hydraulic conductivity. The application of Hirerarchical Cluster Analysis, based on all possible combinations of classification method, showed two main groups of samples. The first group comprises samples from the edges and the second from the central part of the study area. By the application of Discriminant Analysis it was shown that NO(3)(-) and SO(4)(2-) ions are the most significant variables in the discriminant function. Therefore, the first group is considered to comprise all samples from areas not influenced by fertilizers lying on the edges of contaminating activities such as crop cultivation, while the second comprises all the other samples.
authors.affiliation: Department of Geology, Section of Applied Geology & Geophysics, University of Patras, Patras 26500, Greece. nlambrakis@upatras.gr
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Lambrakis
authors.forename: Andreas
authors.initials: A
authors.lastname: Antonakos
authors.forename: George
authors.initials: G
authors.lastname: Panagopoulos
mesh_terms: D000383:Agriculture; D016000:Cluster Analysis; D016002:Discriminant Analysis; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D005308:Fertilizers; D040362:Geographic Information Systems; D055593:Geological Phenomena; D005844:Geology; D009566:Nitrates / Q000032:analysis*; D014872:Water Movements; D014881:Water Supply
chemical_list: D005308:Fertilizers; D009566:Nitrates