A mass spectrometric line for tritium analysis of water and noble gas measurements from different water amounts in the range of microlitres and millilitres

Impact of the Fukushima Accident on 3H and 14C Environmental Levels: A Review of Ten Years of Investigation

The investigation of the impact of the Fukushima accident is still going on although more than ten years have passed since the disaster. The main goal of this paper was to summarize the results of tritium and radiocarbon determinations in different environmental samples, possibly connected with the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. A document containing compiled data may serve as a solid basis for further research in the selected fields. To accomplish such effort, we went through dozens of relevant published papers, reporting 3H and 14C activity concentrations in precipitations, groundwater, seawater, river systems, tree rings, and, in some more extraordinary samples, such as herbaceous plants or debris from the damaged reactor buildings. As the referenced results would not be obtainable without adequate analytical techniques, the most common methods for routine measurement of tritium and radiocarbon concentrations are discussed as well. We believe that the correct identification of the affected environmental compartments could help quantify the released 3H and 14C activities and track their following fate, which could be especially important for plans to discharge contaminated water from the FDNPP in the upcoming years.

Chemical and isotopic composition of CO2-rich magnesium-sodium-bicarbonate-sulphate-type mineral waters from volcanoclastic aquifer in Rogaška Slatina, Slovenia

Bottled natural mineral waters from an andesitic aquifer in Slovenia are enriched in magnesium (1.1 g/l), sulphate (2.2 g/l) and dissolved inorganic carbon (204 g/l). We analysed major ions, trace elements, tritium activity, ¹⁴C, δ¹⁸O_H2O, δ²H_H2O, δ¹³C_DIC, gas composition and noble gases in six wells. In addition, ⁸⁷Sr/^/86Sr, δ³⁴S_SO4 and δ¹¹B were analysed here for the first time. Stable isotopes with δ¹⁸O = -11.97 to -10.30‰ and δ²H = -77.3 to -63.8 confirm meteoric origin. CO₂ degassing is evident at three wells, causing the oxygen shift of about -1.3‰. Tritium activity was detectable only in the shallowest well, where the freshwater component was dated to the 1960s. δ¹³C_DIC in five waters is -1.78 to + 1.33‰, typical of carbonate dissolution. Radiocarbon is low, 1.03-5.16 pMC. Chemical correction with bicarbonate concentration and δ¹³C correction methods gave best mean residence times, slightly longer than previously published. Sulphate has δ³⁴S 26.6-28.9‰ and δ¹⁸O 8.9-11.1‰ due to dissolution of evaporites in carbonate rocks. Boron at concentrations of 1.2-6.1 mg/l has two origins: δ¹¹B = 11.3-16.4‰ from hydrothermal alteration and δ¹¹B = 26.6-31.7‰ from carbonate dissolution. Strontium at concentrations of 0.5-22.0 mg/l has ⁸⁷Sr/^/86Sr, indicating three sources: 0.7106 for Miocene clastic rocks, 0.7082 for Triassic carbonates and 0.7070 for Lower Oligocene andesitic rocks. CO₂ represents the majority of the dissolved (> 98.84 vol%) and separated gas (> 95.23 vol%). Methane is only found in two wells with a max. of 0.30 vol%. All waters show excess helium and 16-97% of mantle-derived helium. Since all show subsurface degassing, the paleo-infiltration temperature could not be calculated.

Combined use of conventional and clumped carbonate stable isotopes to identify hydrothermal isotopic alteration in cave walls

Alteration of conventional carbonate stable isotopes (δ¹⁸O, δ¹³C) in cave walls has been shown to be a useful tool to identify cave formation driven by deep-seated processes, i.e., hypogene karstification. If combined with a prior information on the paleowater stable isotope composition, further insights can be obtained on the temperature and the source of the paleowater. Clumped isotope composition (Δ₄₇) of carbonates is an independent measurement of temperature, and if combined with the conventional stable isotopes, can provide information on the paleowater stable isotope composition. On the example of Provalata Cave (N. Macedonia), we apply for the first time, both conventional and clumped stable isotope analysis, and identify two different isotope alteration trends, reflecting two distinct hydrothermal events: an older, hotter one, where isotope alteration was likely related to isotope diffusion, lowering the δ¹⁸O values of the carbonate; and a younger one, related to the cave formation by low-temperature CO₂-rich thermal waters, with dissolution-reprecipitation as the alteration mechanism, causing decrease in δ¹⁸O values, and unexpected increase in δ¹³C values. The findings are further corroborated by additional insight from optical petrography and cathodoluminescence microscopy, as well as fluid inclusion analysis of secondary calcite crystals related to the cave forming phase.

Modulation of Cosmogenic Tritium in Meteoric Precipitation by the 11-year Cycle of Solar Magnetic Field Activity

The relationship between the atmospheric concentration of cosmogenic isotopes, the change of solar activity and hence secondary neutron flux has already been proven. The temporal atmospheric variation of the most studied cosmogenic isotopes shows a significant anti-correlation with solar cycles. However, since artificial tritium input to the atmosphere due to nuclear-weapon tests masked the expected variations of tritium production rate by three orders of magnitude, the natural variation of tritium in meteoric precipitation has not previously been detected. For the first time, we provide clear evidence of the positive correlation between the tritium concentration of meteoric precipitation and neutron flux modulated by solar magnetic activity. We found trends in tritium time series for numerous locations worldwide which are similar to the variation of secondary neutron flux and sun spot numbers. This variability appears to have similar periodicities to that of solar cycle. Frequency analysis, cross correlation analysis, continuous and cross wavelet analysis provide mathematical evidence that the correlation between solar cycle and meteoric tritium does exist. Our results demonstrate that the response of tritium variation in precipitation to the solar cycle can be used to help us understand its role in the water cycle.