Mineral waters in Slovakia — Evaluation of chemical composition stability using both historical records and the most recent data

A methodology of temporal chemical composition stability of mineral waters is presented. Both historical chemical analyses records and modern water quality monitoring information are interpreted. Historical records can represent a precious background, but they suffer from the lack of information, short association of the analysed components and analytical methods applied; and thus can be evaluated only descriptively. Results of mineral water quality monitoring are processed by statistical methods. Selection of the proper statistical criteria was tested on time series of various sources of Slovak mineral waters. As the most suitable criteria of stability, the 1.5 IQR parameter was selected. Temporal stability of chemical composition of mineral waters is conditioned by many factors both of natural and anthropogenic origin. By help of the criteria proposed, together with limits for the dataset population, time factor and qualified approach can result into a profound estimation of chemical composition stability of mineral waters in time.

Research highlights
► historical mineral water analyses can be evaluated only descriptively
► the most suitable criteria of stability is 1.5 IQR statistical parameter
► 1.5 IQR must be calculated from a minimum of 5 data from 2 to 3 year monitoring
► analyses of the hydrogeological conditions and the technology of exploitation is important
► 1.5 IQR is applicable in bottling and balneological practice and legislative decisions