Radioactivity of cigarettes and the importance of (210)Po and thorium isotopes for radiation dose assessment due to smoking.

Tobacco and tobacco smoke are very complex mixtures. In addition to various chemical and organic compounds they also contain natural radioactive elements (radionuclides). In this work, the natural radionuclide activity concentrations ((234)U, (238)U, (228)Th, (230)Th, (232)Th, (226)Ra, (210)Pb and (210)Po) of nine different cigarette samples available on the Slovenian market are reported. In addition to (210)Po, the transfer of thorium isotopes from a cigarette to a smoker's body and lungs have been determined for the first time. Cigarette smoke and exhaled air from smokers' lungs were collected from volunteer smokers (C-4 brand) to determinate what quantity of (210)Po and thorium isotopes is transferred from the tobacco to the smoker's lungs. Cigarette ash and smoked filters were also collected and analysed. Among the determined isotopes, (210)Pb and (210)Po showed the highest activity concentrations. During the smoking of one cigarette approximately 22% of (210)Po (and presumably its predecessor (210)Pb), 0.6% of (228)Th, 24% of (230)Th, and 31% of (232)Th are transferred from the cigarette and retained in the smoker's body. The estimated annual effective dose for smokers is 61 µSv/year from (210)Po; 9 µSv/year from (210)Pb; 6 µSv/year from (228)Th; 47 µSv/year from (230)Th, and 37 µSv/year from (232)Th. These results show the importance of thorium isotopes in contributing to the annual effective dose for smoking.

Radionuclides in the adriatic sea and related dose-rate assessment for marine biota.

Artificial and natural radionuclides were determined in the Adriatic Sea in the seawater and sediment samples in the period from 2007 to 2011. The sampling areas were coastal waters of Slovenia, Croatia and Albania, together with the deepest part of the Adriatic in South Adriatic Pit and Otranto strait. Sampling locations were chosen to take into account all major geological and geographical features of this part of the Adriatic Sea and possible coastal influences. After initial sample preparation steps, samples were measured by gamma-ray spectrometry. In the seawater 4°K activity concentrations were in the range from 6063 to 10519 Bq m⁻³, ¹³7Cs from 1.6 to 3.8 Bq m⁻³, ²²6Ra from 23 to 31 Bq m⁻³, ²²8Ra from 1 to 25 Bq m⁻³ and ²³8U from 64 to 490 Bq m⁻³. The results of sediment samples showed that 4°K was in the range from 87 to 593 Bq kg⁻¹, ¹³7Cs from 0.8 to 7.3 Bq kg⁻¹, ²²6Ra from 18 to 35 Bq kg⁻¹, ²²8Ra from 4 to 29 Bq kg⁻¹ and ²³8U from 14 to 120 Bq kg⁻¹. In addition, the ERICA Assessment Tool was used for the assessment of dose rates for reference marine organisms using the activity concentrations of the determined radionuclides in seawater. The assessment showed that for the most of the organisms, the dose rates were within the background levels, indicating that the determined values for seawater does not pose a significant risk for the most of marine biota. In the study, the results are critically discussed and compared with other similar studies worldwide. Generally, the activity concentrations of the examined radionuclides did not differ from those reported for the rest of the Mediterranean Sea.

(210)Po and (210)Pb activity concentrations in Mytilus galloprovincialis from Croatian Adriatic coast with the related dose assessment to the coastal population.

Activity concentrations of (210)Po and (210)Pb in the species Mytilus galloprovincialis from Croatian Adriatic coast were determined. The samples were collected in thirteen sampling places which are also a part of Croatian Mediterranean mussel watch project. The results of (210)Po and (210)Pb activity concentrations were found to vary between (22.1±2.5)-(207±21) Bq kg(-1) fresh weight and (2.8±1.4)-(9.3±0.7) Bq kg(-1) fresh weight, respectively. (210)Po/(210)Pb ratio ranged between 6.2 and 30.7. The highest measured activities were found in the enclosed basins of the Neretva channel, where the majority of Croatian mussel cultivation is taking place. The estimated consequent average total annual effective ingestion dose due to (210)Po and (210)Pb from mussel consumption in Croatian coastal region is 202±99 µSv with 96% contribution of (210)Po to the total effective dose.

Levels of ²¹°Po and ²¹°Pb in fish and molluscs in Slovenia and the related dose assessment to the population.

²¹°Po and ²¹°Pb activity concentrations in fish from the Slovenian part of Adriatic Sea, in the vicinity of a former uranium mine at Zirovski vrh and from the Slovenian market were determined. In addition, ²¹°Po and ²¹°Pb activity concentrations in squid from the Slovenian market and in mussels from the Slovenian part of the Adriatic Sea were also determined. Fish, squid and mussel consumption in Slovenia was assessed from the data available from Eurostat and Food and Agriculture Organisation (FAO) and the data used for the corresponding dose calculation. Fish species with the highest activity concentrations were grilled to assess possible loss of ²¹°Po during the food preparation process. Samples were freeze dried and radiochemical separation of ²¹°Po and ²¹°Pb was performed. Measurements of ²¹°Po were performed by alpha spectrometry and ²¹°Pb by a low background gas-flow proportional counter. ²¹°Po activity concentrations in fish, squid and mussels were from 0.039 to 35.0 Bqkg⁻¹ fresh weight and ²¹°Pb activity concentrations were from 0.08 to 3.03 Bqkg⁻¹ fresh weight. Grilling of fish resulted in no significant loss of ²¹°Po at 90°C. The assessed combined annual effective ingestion dose due to ²¹°Po and ²¹°Pb for fish, squid and mussels consumed in Slovenia is 47.6 µSv year⁻¹.