INITIAL EVALUATIONS OF NATURAL (226Ra, 232Th AND 40K) AND ARTIFICIAL (137Cs) RADIO ISOTOPE ACTIVITIES IN ARZULAR-YITIRMEZ-DÖLEK (GÜMÜSHANE) MINERALIZATION/ALTERATION FIELDS

Within the scope of this study, the first evaluations of natural (226Ra, 232Th and 40K) and artificial (137Cs) radio isotope activities of the Arzular-Yitirmez-Dölek (Gümüşhane) mine/alteration site were carried out. Measurements were carried out with Poptop Ortec gamma rays detector on 22 soil samples collected from the field. When the natural 232Th, 226Ra and 40K activities of the area are compared with the weighted world averages, it has been determined that the 40K and 226Ra activities exceed the world averages in most of the sampling points, and the 232Th activities are below the weighted world average except for a few sampling points. It was observed that the artificial 137Cs activities in the field were above the detection limit and exceeded 2 Bq/kg except for a few sampling points. It has been evaluated that the high 137Cs activities in the field may be associated with a human-induced effect, especially the accident at the Chernobyl nuclear power plant. Parameters such as radiological hazard indices, Ra equivalent activity value, absorbed dose rate and annual effective dose rate were also calculated for the field. Considering the results obtained from these parameters, it was concluded that it would be beneficial to study the Arzular-Yitirmez-Dölek mineralization/alteration field in more detail in terms of natural and artificial radioisotope activities.

Soil mineral analysis and environmental radioactivity in Ghizer, Eastern Hindukush, Pakistan

Distribution of natural and anthropogenic radionuclides (226Ra, 232Th, 137Cs and 40K) was determined in 32 samples from Ghizer, an Eastern Hindukush district at an altitude of 2286 m in Pakistan using high resolution gamma-ray spectrometry. Mineralogical analysis by X-ray diffractometry identified quartz, calcite, albite and anorthite as major phases whereas actinolite, chlorite serpentine and kaolinite as minor phases. The activity concentrations for 226Ra, 232Th, 137Cs and 40K varied from 25.2 ± 1.7 to 145.3 ± 10.1 Bq kg−1, 24.9 ± 1.1 to 197 ± 9 Bq kg−1, 2.03 ± 0.21 to 16.7 ± 1.1 and 252 ± 6 to 1433 ± 35 Bq kg−1, respectively. The samples yielded average radium equivalent activity as 178.4 ± 23.3 Bq kg−1. The majority of the samples revealed external hazard index and representative level index less than one. The average air absorbed dose rate was 91.2 ± 13.6 nGy h−1 corresponding to the annual effective dose rate 111.8 ± 17.4 μSv y−1. These values were higher than the world averages for air absorbed dose rate and outdoor annual effective dose rate. Principal component analysis was applied to obtain distribution pattern within the samples and among the radionuclides.

Radioactivity level of coastal sediments and water across the Sangihe Island as the outlying islands of Indonesia

Indonesia as an archipelagic country is very concerned about maritime development, the outlying islands are the entrance for potential threats of radioactive distribution from global waters. Furthermore, the outlying islands have functions such as territorial defence, security, and sovereignty, economic and ecological. As environmental protection, level of natural and anthropogenic radioactivity was performed due to potential threats. The activity concentration of natural (226Ra, 232Th, and 40K) radionuclides inshore sediments samples are range from 3.44 ± 0.01 Bq kg−1, 5.13 ± 0.03 Bq kg−1 and 151.42 ± 0.04 Bq kg−1 respectively and average concentration level of anthropogenic of 137Cs in sediment and seawater obtained were 0.35 Bq kg−1 and 0.83 Bq m3 respectively. The concentrations value of NORM was lower compare to another region but the ratio sequence 226Ra<232Th<40K relatively have same pattern. The presence of fission product 137Cs in this region comes from global fallout since no nuclear activities in Indonesia and the level of 137Cs are almost same as the estimation the concentration 137Cs in the Pacific Ocean and comparable with other studies. Radioactivity levels in all samples are under the value of radiological hazard index (0.004-0.039, trace hold h-index=1) and annual effective dose rate are in save level (0.01 mSv/y, recommended limit AED=1mSv/year). The level of NORM radioactivity is locally and varied for each region meanwhile anthropogenic radioactivity are global and comparable since there are no nuclear activity in Indonesia.

Technical and radiological characterisation of fly ash and bottom ash from thermal power plant

Huge quantities of fly ash and bottom ash are generated from thermal power plants and it presents great concern for country, mainly due to the environmental effects. In this study, fly ashes and bottom ash were characterized from technical and radiological aspects. Health effect due to the activity of radionuclides 226Ra, 232Th and 40K was estimated via radium equivalent activity (Raeq), external hazards index (Hex), the external absorbed dose rate (D) and annual effective dose rate (EDR). The specific surface area (40.25 m2 g−1), particle density (1.88 g cm−3) and LOI (23.49%) were typical for bottom ash. Siliceous fly ash contained 32% reactive silica. The annual effective dose rate for all ashes is ≤ 0.2 mSv y−1. Both, fly ash and bottom ash present potential secondary raw materials to be used for building purposes as result of their technological and radiological assessment.

Evaluation of Natural Radioactivity Levels and Potential Radiological Hazards of Common Building Materials Utilized in Mediterranean Region, Turkey

Radiometric measurement of building materials is very important to assess the internal and external exposure caused by the ionizing radiation emitted from terrestrial radionuclides in building materials. The activity concentrations of 226Ra, 232Th, and 40K in fifty-eight samples of fifteen different structural and covering building materials commonly used in Osmaniye province located in the Mediterranean region of Turkey were measured by using gamma-ray spectroscopy. The activity concentrations of 226Ra, 232Th and 40K varied from 2.5 ± 0.1 (marble) to 145.7 ± 4.4 (clay brick), 1.3 ± 0.1 (marble) to 154.3 ± 4.1 (marble) and 8.6 ± 0.2 (sand) to 1044.1 ± 70.3 (granite), respectively. Radiological parameters (activity concentration index, alpha index, indoor absorbed gamma dose rate and the corresponding annual effective dose rate, and excess lifetime cancer risk) were estimated to evaluate the health hazards associated with these building materials. Since the estimated values of these parameters are within the recommended safety limits or criteria values, the use of the studied building materials in the construction of dwellings can be considered to be safe for the residents of the region.

Annual Effective Dose from Natural Background Radiation in Pokhara, Nepal

Measurement of outdoor natural background radiation doses at different locations of Pokhara city, Nepal was carried out using GCA-07W, Nuclear Regulatory Commission (NRC) certified Geiger Muller (GM) detector. From the measurements, the least value of background radiation dose rate was found to be 0.26 ± 0.08 μSv/hr for Mahendra Cave area, and the highest value of dose rate was found to be 0.65 ± 0.12 μSv/hr for Prithvi Narayan Campus. The average annual effective dose rate of Pokhara city was found to be 0.56 ± 0.12 mSv/yr ranging from 0.31 ± 0.09 mSv/yr to 0.80 ± 0.14 mSv/yr. The radiation levels in Pokhara, the most populated city of the western development region of Nepal, were found to be within the secure limit for areas of the normal background recommended by the International Commission on Radiological Protection (ICRP) (1 mSv/yr). Further, the current result was compared with the previous study of annual effective dose rate measured in Kathmandu city. Comparable value of the average annual effective dose rate in Pokhara and Kathmandu was obtained.

RADIOLOGICAL HEALTH RISK ASSESSMENT AT ASHAKA CEMENT COMPANY, GOMBE STATE, NIGERIA

Enhanced natural radioactivity due human activities can be harmful to the environment and human health depending on the amount of exposure. A sensitive gamma spectrometry system consisting of 7.6cm x 7.6cm Nal(Tl) scintillation detector coupled with Canberra series 10 plus multichannel analyzer was used to determine the radioactivity concentration of natural radionuclides 232Th, 238U, and 40K in soil samples collected from the five communities around Ashaka Cement Company. The results obtained showed that the radionuclides are present in the soil samples in varying concentrations ranging from 11.36 Bq kg−1 measured in Badabdi to 98.06 Bq kg−1 in Ashaka Cement for 238U, from 13.21 Bq kg−1 in Jajami to 44.36 Bq kg−1 in Ashaka Cement for 232Th and from 65.50 Bq kg−1 in Gwangila to 415.62 Bq kg−1 in Julgwal Barkono for 40K. Absorb dose rate and annual effective dose rate due to these radionuclides are in the range 36 nGy h−1 in Badabdi to 50 nGy h−1 in Ashaka Cement and 0.132 mSv to 0.194 mSv in Badabdi and Ashaka Cement, respectively. These results are within global limits recommended by UNSCEAR. Therefore, the environmental matrices around the factory could be used without any restrictions

Assessment of the Natural Radioactivity of Polish and Foreign Granites Used for Road and Lapidary Constructions in Poland

The measurements of the specific activity of natural radioactive isotopes of radium (226Ra), thorium (232Th) and potassium (40K) in chosen samples of imported (China, Finland, Spain, India, Sweden) and Polish (Izerski, Karkonosze, Siedlimowicki, Strzegomski, Strzelinski) granites were performed. The measurements were carried out with 2 × 2” NaI(Tl) scintillation detector. The measured specific activity on natural radioactive isotopes were within the following ranges: 5.8–312 [Bq kg−1], 5.5–189 [Bq kg−1] and 109–1590 [Bq kg−1] for 226Ra, 232Th and 40K, respectively. Obtained concentrations of radioactive isotopes allowed to perform the analysis of the exposure of the humans from the ionizing radiation emitted by the granites. The determination of the exposure consisted in the calculation of absorbed gamma dose rate (D) [nGy h−1] for each sample, which fell in the range between 20 and 511 [nGy h−1], annual effective dose rate (AED) [mSv year−1] ranging between 0.10 and 2.50 [mSv year−1], radium equivalent activity (Raeq) [Bq kg−1] with values between 22 and 570 [Bq kg−1], external and internal hazard indices (Hex) and (Hin) falling in the ranges 0.06−1.53 and 0.08–2.41 respectively, as well as gamma (Iγ) and alpha (Iα), representative level indices with values 0.08–2.0 and 0.029–1.56, respectively. Moreover, obtained results were compared with the international standard values given by the European Commission (EC), the United Nations Scientific Committee on the Effects of Atomic Radiation given in UNSCEAR Reports, and the results of research from other laboratories.

NATURAL RADIOACTIVITY MEASUREMENT AND DOSE ASSESSMENT OF BEACH PLACER SANDS IN THE COASTAL REGION OF TAMIL NADU (INDIA)

A preliminary study was carried out to determine the radioactivity concentration of 232Th, 226Ra and 40K in beach placer sands from 13 locations along the coast line of Tamil Nadu state, India. The ambient dose rates varied from 9 to 467 nGy h−1. The activity concentrations of radionuclide 232Th, 226Ra and 40K ranged from 5.2 to 683 Bq kg−1, 13 to 198 Bq kg−1 and 107 to 421 Bq kg−1, respectively. The annual effective dose rate ranges from 27 to 620 μSv y−1 and was higher at seven beaches in comparison to the UNSCEAR annual worldwide average value.

Study of the radioactivity in environmental soil samples from Eastern Anatolia Region of Turkey

In this study, a detailed γ-ray spectrometer survey was performed to obtain the baseline data on natural and fallout radioactivity in soil samples (10–30 cm depth) collected from Iğdır which is a province in Eastern Anatolia Region of Turkey and located along the border with Armenia. Metsamor Nuclear Power Plant in Eastern Armenia is only about 20 km away from Iğdır province. The average activity concentrations of226Ra,232Th,40K and137Cs in the soil samples were found as 19.1±0.6 (range: 12.8–31.2 Bq kg−1), 21.9±0.6 (range: 11.6–36.8 Bq kg−1), 437.7±10.3 (range: 285.0–613.7 Bq kg−1) and 11.8±1.1 Bq kg−1, (range: 2.5–51.1 Bq kg−1), respectively. The radiological hazards caused by ionizing radiation emitted from these radionuclides on the population living in the region were assessed by estimating radiological parameters such as absorbed γ dose rate in outdoor and the corresponding annual effective dose rate from external exposure, annual effective dose rate from inhalation of radon and excess lifetime cancer risk. The results revealed that there is no significant radiological hazard for human population because the average values of radiological parameters are within the recommended limits.