Naslov
Isotopic composition of spring waters from Croatian karst regions: Gacka River area

Autori
Bojić, Diana ; Mandić, Magda ; Roller-Lutz, Zvjezdana ; Lutz, Hans O: Kapelj, Sanja ; Horvatinčić, Nada ; Krajcar Bronić, Ines ; Sironić, Andreja

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Proceedings of the European Society for Isotope Research : ESIR IX / Tamas, Tudor - Cluj - Napoca : Cluj University Press, 2007, 9-9

Skup
European Society for Isotope Research : ESIR IX

Mjesto i datum
Cluj-Napoca, Rumunjska, 23.06.2007. - 28.06.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
karst; isotopes; 18O; tritium; Gacka

Sažetak
The main springs of the Gacka river drainage area (Majerovo vrelo, Tonković vrelo and Pećina) have been studied by means of stable (18O) and radioactive (3H) isotope measurement. This area is situated in the Dinaric karst that comprises very important groundwater storage reservoirs. Since karst is characterized by high permeability, porosity and crevices in which water moves in complex subterranean networks, it is very sensitive to any kind of pollution. Gacka river is located in the Lika region at an altitude of about 400 m above sea level. Although its climatic conditions are mainly continental, the situation is complicated by the occasional influence of maritime Adriatic air masses. Water samples from the three springs (continuous sampling, some other springs occasionally) as well as precipitation were collected monthly in the period 2005-2006. Tritium measurements have been performed at the Laboratory for Measurements of Low-level Radioactivity of the Rudjer Bosković Institute, Zagreb, while stable isotope δ 18O measurements were carried out at the new stable isotope facility (Environmental Physics Laboratory) at Rijeka University. In the time period under study, δ 18O in the Gacka precipitation is (– 8.7 ± 2.1) ‰ with seasonal fluctuations typical for continental stations in the area . δ 18O fluctuations in the spring waters are much smaller, indicating well-mixed waters. The three springs have fairly different δ 18O -values although they are located at approximately the same altitude. This indicates that their catchments lie at different altitudes. The spring water temperatures and flow rates show no direct correlation with the ambient temperature and the amount of precipitation. Large precipitation amounts in August and December 2005 have apparently no immediate effect on the spring δ 18O - values. A weak seasonal variation again indicates a delayed response and good mixing. The seasonal tritium distribution for the precipitation in the Gacka area is well correlated with that in Zagreb, the closest GNIP continental station. All three main springs show similar mean tritium concentrations, but much smaller seasonal variations than precipitation, indicating a short mean residence time and good mixing of infiltrated and ground water.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Geologija, Elektrotehnika

Napomena
Studia Universitatis Babes-Bolyai. Geologia 52 (2007) (1) ; ISSN 1221-0803

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