Radioactivity in the Mediterranean flora of the Kastela Bay, Croatia.

This study refers to background activity concentrations of (238)U, (226)Ra, (232)Th, (208)Tl, (40)K, and (137)Cs in soil and plants of the Kastela Bay, Croatia and related plant-soil concentration ratios (CR's). Fourteen different Mediterranean plant species growing in natural conditions have been included and were divided into three major plant groups (grasses and herbs, shrub, tree). Radionuclide activity concentrations were determined by means of high resolution gamma-ray spectrometry. Soil parameters (pH, electrical conductivity, and organic matter content) were also analysed. CR ranges were within one order of magnitude for (40)K (10(-2)-10(-1)), (238)U, and (226)Ra (10(-3)-10(-2)), and two orders of magnitude for (232)Th, (208)Tl, and (137)Cs (10(-4)-10(-2)). There was no statistical difference between the plant groups in radionuclide uptake. Overall statistical analyses indicated a moderate negative relationship between soil concentrations and CR values, and no relationship with soil parameters, except a negative one for (137)Cs. Comparison with literature showed more agreement with studies that were done in the Mediterranean than with ICRP and IAEA databases. Our data not only describe the natural radioactivity of the Bay, but also create a dataset that could be relevant for further radioecological assessments of the Kastela Bay.

Fine structure of the absorbed dose rate monitored in Zagreb, Croatia, in the period 1985-2011.

We report on the fine structure of the absorbed dose rate D which was measured and recorded on a daily basis at the Institute for Medical Research and Occupational Health in Zagreb, Croatia, throughout the period 1985-2011. After the Chernobyl accident, D increased steeply by a factor of 3.5, but this is the only prominent feature in the D versus time (t) curve. In the absence of accidental conditions, the D(t) is flat and amounts to 30-35 pGy/s. Despite the apparent plainness of D(t), its Fourier transform reveals several periodic modulations hidden in the noise. Some of the corresponding periods (6 and 12 months) can be related to seasonal atmospheric changes but this is not the case with the other periods identified (9.3, 13.7, 15.7, 20, 31, and 39 months). These are found to agree well with literature data on periodicities in solar activity, which implies that they are most probably linked to variations in the atmospheric production of (7)Be by cosmic rays.

Radiostrontium activity concentrations in milk in the republic of Croatia for 1961-2001 and dose assessment.

Results of systematic measurements of 90Sr activity concentrations in milk for the period 1961-2001 are summarized. An exponential decline of radioactivity followed the moratorium on atmospheric nuclear testing. The highest activity of 90Sr deposited by fallout, 1,060 Bq m(-2), was recorded in 1963, while the peak 90Sr activity concentration in milk, 1.42 +/- 0.17 Bq L(-1), was recorded in 1964. The values in year 2001 for fallout deposition and milk were 7.7 Bq m(-2) and 0.07 +/- 0.03 Bq L(-1), respectively. The reactor accident at Chernobyl caused higher 90Sr levels only in 1986. 90Sr fallout activity affects milk activity; the coefficient of correlation between 90Sr fallout activity and 90Sr activity concentrations in milk is 0.80. The transfer coefficient from fallout deposition to milk was estimated to be 2.5 x 10(-3) Bq y L(-1) per Bq m(-2). The dose incurred by milk consumption was estimated for the Croatian population, the annual collective effective dose in 2001 being approximately 2.0 person-Sv.

Radioactive contamination of cistern waters along the Croatian coast of the Adriatic sea by 90Sr.

Measurements of radioactive contamination of water samples from cisterns collecting rainwater containing fission products from roofs and other surfaces have been carried out along the Croatian coast of the Adriatic sea since 1968. An exponential decline of radioactivity followed the nuclear moratorium. After the nuclear accident at Chernobyl, higher levels of 137Cs and 90Sr were detected again, with cistern waters being the only environmental samples in Croatia in which elevated 90Sr activities persisted for several years. For the pre-Chernobyl period, the observed mean residence time of 90Sr in cistern waters, estimated to be 6.2 +/- 1.9 y, was similar to that calculated for fallout. Contrary, for the post-Chernobyl time, observed 90Sr mean residence time was calculated to be considerably shorter, reflecting the tropospheric mean residence time. The annual dose for the critical adult population received from 90Sr and 137Cs by drinking cistern water was estimated to be very small, in the 1990's less than few microSv y(-1).

226Ra in drinking water in the Republic of Croatia.

Owing to its exceptional radiotoxicity 226Ra in drinking water may directly affect human health. Its presence was investigated in several categories of drinking water in Croatia: well water, tap water from several municipal water supply systems and bottled mineral water. The method of 226Ra determination was alpha-spectrometric measurement after radiochemical separation. The 226Ra content in all investigated categories of waters are below the legislative level permissible for human health.

Risk estimation of radioactive contamination after the Chernobyl accident using bioindicators.

After the Chernobyl nuclear accident, game meat and, in particular, sheep meat in the Republic of Croatia showed a high degree of radioactive contamination compared to large livestock. The activity concentrations of 131I, 134Cs, and 137Cs were measured in meat and internal organs (i.e., lung, liver, kidney, and heart) of game (e.g., venison, hare, and wild boar) and sheep that were used as biological indicators of radioactive contamination. In order to estimate the importance of game and sheep as a dietary source of radioactivity, the effective dose equivalent for the average and critical population (hunters and livestock raising families) were calculated. The data indicated that sheep meat represents greater risk for the human population, in case of a nuclear accident, than game meat. The share of meat from sheep (4.4%) prevailed over the share of meat from game (0.5%) when comparing the average intake of meat per inhabitant in Croatia. This result pointed to an increased risk for families who depend mostly on sheep meat in the case of a nuclear accident.

Risk estimation of radioactive contamination after the Chernobyl accident using bioindicators

After the Chernobyl nuclear accident, game meat and, in particular, sheep meat in the Republic of Croatia showed a high degree of radioactive contamination compared to large livestock. The activity concentrations of I, Cs, and Cs were measured in meat and internal organs (i.e., lung, liver, kidney, and heart) of game (e.g., venison, hare, and will boar) and sheep that were used as biological indicators of radioactive contamination. In order to estimate the importance of game and sheep as a dietary source of adioactivity, the effective dose equivalent for the average and critical population (hunters and livestock raising families) were calculated. The data indicated that sheep meat represents greater risk for the human populations, in case of a nuclear accident, than game meat. The share of meat from sheep (4.4

) prevailed over the share of meat from game (0.5

) when comparing the average intake of meat per inhabitant in Croatia. This result pointed to an increased risk for families who depend mostly on sheep meat in the case of a nuclear accident(AU)

[The importance of bioindicators in the evaluation of radioactive contamination]. / Vaznost bioindikatora pri procjeni radioaktivne kontaminacije.

The paper is a survey of investigations into radioactive contamination of selected plant and animal species (bioindicators) which have the capacity for multiple accumulation of fission products. Literature data on the contamination of bioindicators are compared with special reference to the accumulation of 131I, 137Cs and 90Sr as a result of atmospheric nuclear experiments and the nuclear accident at Chernobyl.