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The isotope composition of precipitation has been monitored in monthly precipitation at Zagreb, Croatia, since 1976. Here, we present a statistical analysis of available long-term isotope data (3H activity concentration, δ2H, δ18O, and deuterium excess) and compare them to basic meteorological data. The aim was to see whether isotope composition reflected observed climate changes in Zagreb: a significant increase in the annual air temperature and larger variations in the precipitation amount. Annual mean δ18O and δ2H values showed an increase of 0.017‰ and 0.14‰ per year, respectively, with larger differences in monthly mean values in the first half of the year than in the second half. Mean annual d-excess remained constant over the whole long-term period, with a tendency for monthly mean d-excess values to decrease in the first half of the year and increase in the second half due to the influence of air masses originating from the eastern Mediterranean. Changes in the stable isotope composition of precipitation thus resembled changes in the temperature, the circulation pattern of air masses, and the precipitation regime. A local meteoric water line was obtained using different regression methods, which did not result in significant differences between nonweighted and precipitation-weighted slope and intercept values. Deviations from the Global Meteoric Water Line GMWL (lower slopes and intercepts) were observed in two recent periods and could be explained by changes in climate parameters. The temperature gradient of δ18O was 0.33‰/°C. The tritium activity concentrations in precipitation showed slight decreases during the last two decades, and the mean A in the most recent period, 2012–2018, was 7.6 ± 0.8 Tritium Units (TU).

We measured accumulation rates of organic carbon (OC) and total nitrogen (TN) and stable carbon (␦ 13 C org ) and nitrogen isotopes (␦ 15 N) in the sediments of two mountain lakes (Lake Ledvica and Lake Planina, northwest Slovenia). Marked variations of these parameters were observed in both sediments. OC accumulation rates ranged from 4 to 23 g m Ϫ2 yr Ϫ1 in Lake Ledvica, whereas in Lake Planina they were one order of magnitude higher and increased substantially in the upper sediments. ␦ 13 C org and ␦ 15N decreased upward in Lake Ledvica, from Ϫ25.5‰ to Ϫ28.4‰, and from ϩ2.1‰ to Ϫ3.4‰, respectively. In contrast, substantial variations in the ␦ 13 C org profile, ranging from Ϫ30.9‰ to Ϫ37.4‰, but a quite uniform ␦ 15

The stable isotopic composition of hydrogen and oxygen (δ 2 H and δ 18 O) and tritium activity ( 3 H) are monitored in monthly precipitation at Ljubljana since 1981. Here we present complete set of numerical data and the statistical analysis for period

Bottled water is a food product that considerably depends on the environment from which it originates, not only at the place where it is produced, but predominantly on the conditions in the recharge area of the wells captured for bottling. According to their source and the bottling process, bottled waters can be divided into natural and artificially sparkling waters, still and flavoured waters. These waters originate from various parts of the hydrological cycle and their natural origin is reflected in their hydrogen and oxygen stable isotopic compositions (delta(2)H and delta(18)O). A total of 58 domestic and foreign brands and 16 replicates of bottled waters, randomly collected on the Slovene market in September 2004, were analysed for delta(2)H and delta(18)O. The isotopic composition varied between -83 per thousand and -46 per thousand with an average of -66 per thousand for hydrogen, and between -11.9 per thousand and -7.5 per thousand with an average of -9.6 per thousand for oxygen. This investigation helped (1) to determine and test the classification of bottled waters, (2) to determine the natural origin of bottled water, and (3) to indicate differences between the natural and production processes. The production process may influence the isotopic composition of flavoured waters and artificially sparkling waters. No such modification was observed for still and natural sparkling waters. The methods applied, together with hydrological knowledge, can be used for the authentication of bottled waters for regulatory and consumer control applications.

The stable isotopic composition of hydrogen and oxygen (δ O + (9,76 ± 1,93). Nakloni izra~unanih premic so si med seboj podobni, kar nakazuje, da je porazdelitev padavin relativno homogena in da je {tevilo mese~nih vrednosti z nizkim devterijevim presežkom majhno. Srednja tehtana vrednost devterijevega presežka zna{a 10,3 ‰ in nakazuje prevladujo~i vpliv zra~nih mas iz Atlantika.Temperaturni koeficient za δ 18 O pa zna{a 0,30 ‰/°C. Tudi podatki o aktivnosti tricija v mese~nih padavinah kažejo sezonske spremembe. Srednja tehtana vrednost zna{a 8,5 TU in ne nakazuje padajo~ega trenda.

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