Degree of Correlation Between Mineralization of Water and Bacterial Load in Sub-Mediterranean Karstic Basin

Water quality assessment is a fundamental aspect of research and conservation of aquatic resources. It is a clear indication of ecosystem health, which allows direct identification of threats to homeostasis. Selection of parametres used in water quality assessment is a crucial step in order to obtain precise and accurate data on condition of water and possible sources of impairment. This study aims to investigate a degree of correlation of total coliforms, as a general bacteriological water quality indicator with electrical conductivity, as a measure of water mineralization and determine whether there is any predictive value in connection of these parametres. It was also aimed to obtain data on bacteriological water quality and examine bacteriological load of aquatic ecosystems at selected sites. Sampling was conducted at river Neretva, its five tributaries and two large artificial lakes on Neretva, over spring and autumn to reflect any differences in microbial numbers after prolonged draught and flood periods. Water parametres measured were: temperature, pH, dissolved oxygen, electrical conductivity, total coliforms and Escherichia coli. Results show that elevated numbers of total coliform bacteria do not cause an increase in electrical conductivity, but elevated electrical conductivity values indicate a higher degree of mineralization, suggesting an increased bacterial load. Presence of tuff particles in water, as a convenient substrate facilitates prolonged survival of bacteria, resulting in elevated bacterial numbers in travertine rivers.