Radon Hazard in Central Italy: Comparison among Areas with Different Geogenic Radon Potential

Radon (222Rn) is a natural radioactive gas formed in rocks and soil by the decay of its parent nuclide (238-Uranium). The rate at which radon migrates to the surface, be it along faults or directly emanated from shallow soil, represents the Geogenic Radon Potential (GRP) of an area. Considering that the GRP is often linked to indoor radon risk levels, we have conducted multi-disciplinary research to: (i) define local GRPs and investigate their relationship with associated indoor Rn levels; (ii) evaluate inhaled radiation dosages and the associated risk to the inhabitants; and (iii) define radon priority areas (RPAs) as required by the Directive 2013/59/Euratom. In the framework of the EU-funded LIFE-Respire project, a large amount of data (radionuclide content, soil gas samples, terrestrial gamma, indoor radon) was collected from three municipalities located in different volcanic districts of the Lazio region (central Italy) that are characterised by low to high GRP. Results highlight the positive correlation between the radionuclide content of the outcropping rocks, the soil Rn concentrations and the presence of high indoor Rn values in areas with medium to high GRP. Data confirm that the Cimini–Vicani area has inhalation dosages that are higher than the reference value of 10 mSv/y.

Assessment of the Radiation and Health Physics Situation in the Area of Ship Repair Enterprises in Kamchatka Krai

The objectives of the study are to examine the radiation and health physics situation in the area of ship repair enterprises servicing ships with nuclear power installation; to assess its possible impact on the environment and the population. Materials and research methods. The study of radiation and health physics situation on the territory was conducted by walking gamma survey using portable gamma spectrometric complexes MKS-01A "Multirad-gamma" and MKS-AT6101C. Gamma-spectrometric and radiochemical methods of analysis were used to determine the specific activity of man-made and natural radionuclides in environmental samples. Results of the study and their analysis. Practical medical and hygienic measures to study the radiation and health physics situation were carried out in 2019. It was found that the ambient equivalent dose rate in the areas of ship repair enterprises is at the level of regional values and does not exceed 0.12 μSv/h. Radionuclide specific activity in the soil of the surveyed areas does not exceed 4.5 Bq/kg — for 90Sr and 12 Bq/kg — for 137Cs, which does not exceed the established norms for unrestricted use of solid materials. Radionuclide content in the sea water samples taken in the area of closed administrative territorial unit Krasheninnikov Bay does not exceed on average: for 137Cs — 7 mBq/L, for 90Sr — 2.1 mBq/L. When comparing the results obtained with the official data on the radionuclide content in the water of Avacha Bay (90Sr up to 2.08 mBq/L at the annual average of 1.14 mBq/L), we may state that they are at the same level as the regional ones. Radionuclide content in bottom sediment samples varies within the following limits: for 137Cs — from 0.14 to 3 Bq/kg, for 90Sr — from 0.11 to 1.5 Bq/kg and is similar to the general values for soil samples. Thus, the radiation and health physics characteristics of the study area vary little and remain practically at the level of the results of studies conducted in 2014-2015. The content of man-made radionuclides in the samples of environmental objects is at the level of average values typical for the region. Potentially radiation-hazardous works carried out in 2019 at enterprises of closed administrative territorial unit Vilyuchinsk had no reliable radiation impact on the environment and population.

Reconstruction of the absorbed dose of ionizing radiation for helophytes in the water bodies of the near emergency zone at the Chornobyl NPP

Based on modeling the dynamics of the Chornobyl emission radionuclide content in the components of the most polluted reservoirs of the Chornobyl Exclusion Zone, the absorbed dose for helophytes was reconstructed. During the growing season of 1986, the absorbed dose of plants of Glyboke Lake was 78 Gy, Daleke Lake 39 Gy. The absorbed dose rate of plant roots was 2.4 times higher than that of aboveground organs. According to actual data, in the period 2016 - 2019 in the Glyboke Lake average dose of external and internal plant irradiation was about 7.5 mGy/year, and in the Daleke Lake 5.6 mGy/year. On abnormally contaminated sections of the Glyboke Lake, the external dose reaches 0.5 - 1.0 Gy/year. During the period 1986 - 2020, the maximum cumulative (biological) dose of helophytes of Glyboke Lake can be 190 Gy, Daleke Lake 80 - 85 Gy.

Radionuclides Content in Tissues and Organs of Pumpkinseed Lepomis gibbosus (Linnaeus, 1758) from the Zaporizhzhia (Dnipro) Reservoir

The article presents the results of studies on the content of artificial (137Cs, 90Sr) and natural radionuclides (226Ra, 232Th, 40K) in tissues and organs of various individuals of pumpkinseed Lepomisgibbosus (Linnaeus, 1758) from the Zaporizhzhia (Dnipro) reservoir. It has been revealed that in the bones of sexually mature pumpkinseed females, the content of radionuclides 137Cs and90Sr is 24.7% and 28.6% less, respectively, than in the bones of males. Summing up the materials of radioecological studies of 2017–2018, the following sequence of tissues and organs of the pumpkinseed by the ability to accumulate radionuclides was obtained: bone> muscle> scales> gills. Research results can be useful for further study on the fish radiation load in the basins of the Dnipro River and during monitoring radioecological research. It was determined that the content of radionuclides in the pumpkinseed muscles did not exceed the permissible levels of radionuclide content for fish as a food product (permissible levels of radionuclide content for 137Cs – 150 Bq/kg, 90Sr – 35 Bq/kg).

A Research Study on the Radiological State of Building Material and the Risk Assessment

The objective of the present study is focused an the assessment of the radiological risk from building materials used in Attica region, Greece. Bricks and concrete com- monly used in Attica region have been studied for both natural radionuclide content and radon exhalation. The high-resolution gamma-ray spectroscopy technique, as well as radon exhalation measurements, have been employed. The technique used for the measurements of the radon exhalation is called "continuous accumulation- counting" method and has been described in detail by the authors in earlier pub- lications. This measurement technique is based on the continuous air flow through a sealed chamber containing the sample and through a scintillation counter (Lucas cell). The counting is continuous as well.

Migration of uranium in the system soil-plant (model experiments)

Migration of uranium-238 in the system soil-plant at an example of a flower crop, marigold (Tagetes erecta) was studied. The above-mentioned components were used to treat the soil after planting. Using the method of sequential fractionation, soil extracts were obtained, with the content of uranium amounting to ~2 %. Upon the introduction of oil and uranium into the experimental system, the portion of uranium increased in the root parts of the plants (µg/sample): from 0.81 to 9.43, and in the above-ground parts (µg/sample): from 0.78 to 17.1; with the introduction of the oilfield water there was the increased extraction of uranium which had earlier been present in the soil while the uranium content in the root and above-ground parts of the plants in the systems containing oil, oilfield water was considerably higher than in the control system (from 1.17 to 6.73 µg as compared with 0.78 in the above-ground parts of the plants and from 9.92 to 12.87 as compared with 0.81 µg in the root parts). Upon the introduction of uranium combined with oil the radionuclide content was significantly different from the content in the root parts (17.1 in the above-ground parts and 9.43 µg in the root parts).