Daily Fluctuations in the Isotope and Elemental Composition of Tap Water in Ljubljana, Slovenia / 7.07.2021

Multiparameter analyses of tap water can provide insight on the role of multiple distinct inputs and relationship between infrastructure and the environment over a range of scales.

There has been a heated discourse about drinking water and its lawful protection in Slovenia lately. We know where the water comes from here in Ljubljana, but how well do we actually know the behaviour of the water supply system itself? With this study, we examined a part of the urban water supply system and performed a 24h multiparameter analysis of tap water. Sampling was performed at Jožef Stefan Institute, where water from two different wellfields (Kleče and Brest) is mixing. Water at this location showed only slight variations in the measured parameters. Due to isotope similarity between sources, concentration of elements provided more information. Using different statistical methods, we observed different grouping based on time of sampling and analysed parameters. By using simple linear mixing model, we have shown Brest wellfield contributes a larger share of water during the day, when water consumption is high. On the other hand, Brest wellfield contribution is low during the night, since Kleče wellfield is able to fulfil most of the demand itself.

The details are presented in the article published in Water: “Daily Fluctuations in the Isotope and Elemental Composition of Tap Water in Ljubljana, Slovenia” prepared by K. Nagode, T. Kanduč, B. T. Zuliani, Bračič-Železnik, B. Jamnik and P. Vreča, available at: