engleski

Variations in environmental distribution of cosmogenic radioisotopes tritium (3H) and radiocarbon (14C) in Croatia

Monitoring of environmental levels of 14C and 3H in Croatia started more then 20 years ago. 14C monitoring included atmospheric CO2, annual plants, tree rings, soil and dissolved carbonates in waters. Tritium monitoring included measurement in precipitation, ground waters, surface waters and atmospheric water vapor. The mean yearly 3H activities in precipitation continuously decrease since the beginning of monitoring approaching slowly the natural equilibrium. The monthly 3H activities show seasonal variations, with maximum in early summer and minimum in early winter. At the sampling site located at the Institute, several periods of higher 3H activities were observed, due to the local contamination with the tritium-labeled material. The 14C concentration in the atmosphere shows also the continuous decrease of the mean yearly values and superposed seasonal fluctuations. Seasonal peak-to-peak variations are higher in the area of the city of Zagreb than at the clean-air site on the mountain (~1000 m a.s.l.) because of the introduction of CO2 (containing no 14C isotope) produced by fossil-fuel combustion in the atmosphere in the city area.

tritium; radiocarbon; atmosphere; Croatia

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