G. Karahan

Radioactivity concentrations and dose assessment for soil samples around Adana, Turkey

The concentrations of natural radionuclides in surface soils around Adana, Turkey were determined using gamma ray spectrometry with an HPGe detector. The natural gamma ray radioactivity of the terrestrial radionuclides in air was calculated throughout different areas of Adana. The average activity concentrations of (238)U, (232)Th and (40)K were found to be 17.6, 21.1 and 297.5 Bq kg(-1), respectively. Outdoor gamma dose measurements in air 1m above ground level were determined by using a portable gamma scintillation detector. The gamma dose measurements in air were taken from the same places where soil samples were taken. Average outdoor gamma dose rates in sample stations were determined as 67 nGy h(-1). The annual effective dose to the public was found to be 82 microSv.

Assessment of natural radioactivity concentrations and gamma dose rate levels in Kayseri, Turkey.

This study assesses the level of background radiation for Kayseri province of Turkey. Natural radionuclide activity concentrations in soil samples were determined using high-resolution gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using a portable gamma scintillation detector. The obtained results of uranium and thorium series as well as potassium ((40)K) are discussed. The present data were compared with the data obtained from different areas in Turkey. From the measured gamma-ray spectra, the average activity concentrations were determined for (238)U (range from 3.91 to 794.25 Bq kg(-1)), (232)Th (range from 0.68 to 245.55 Bq kg(-1)) and (40)K (range from 23.68 to 2718.71 Bq kg(-1)). The average activity concentrations of (238)U, (232)Th and (40)K were found to be 35.51, 37.27 and 429.66 Bq kg(-1), respectively, and 11.53 Bq kg(-1) for the fission product (137)Cs. The highest values of (238)U, (232)Th and (40)K concentrations (794.25 Bq kg(-1), 245.55 Bq kg(-1), 2718.71 Bq kg(-1), respectively) were observed in abnormal samples at Hayriye village. The average outdoor gamma dose rate in air at 1 m above the ground was determined as 114.43 nGy h(-1). Using the data obtained in this study, the average annual effective dose for a person living in Kayseri was found to be about 140.34 µSv.

Risk assessment of baseline outdoor gamma dose rate levels study of natural radiation sources in Bursa, Turkey

Within the scope of this study, gamma radiation dose rate measurements have been carried out in the province of Bursa. The mean outdoor (terrestrial and cosmic) gamma dose rate in this area was 90 nGy h(-1). The cosmic gamma dose rate was measured to be 16 nGy h(-1) at the Iznik lake in the region. The mean annual effective dose due to outdoor gamma radiations was determined to be 110.4 µSv. The collective effective dose equivalent was calculated to be 3.21 × 10(2) man Sv per year. The average relative excess lifetime risk of fatal cancer was calculated at 4.50 × 10(-4) for the people living in the city. The activity concentrations of natural radionuclides such as (238)U series, (232)Th series, (40)K and fission products like (137)Cs in surface soil samples were measured by using an HPGe-based gamma spectrometry system. The mean activity concentration of (238)U series, (232)Th series, (40)K and (137)Cs were found to be 55.9 Bq kg(-1) for (226)Ra, 23.6 Bq kg(-1) for (214)Pb, 22.5 Bq kg(-1) for (214)Bi, 31.3 Bq kg(-1) for (208)Tl, 32.9 Bq kg(-1) for (228)Ac, 430 Bq kg(-1) for (40)K and 5.4 Bq kg(-1) for (137)Cs. The radiation hazards associated with the radionuclides were estimated at an average of 136 Bq kg(-1) by calculating the radium equivalent activity (Ra(eq)). The mean calculated value of the external hazard index (H(ex)) for the soil was found to be 0.37.

Determination of the health hazards due to background radiation sources in the city of Adapazari, Northwestern Turkey

Human body is exposed to ionising radiations both internally and externally by mainly high-energy cosmic ray particles incident on the earths atmosphere and radioactive nuclides that originated in the earths crust. The main objective of this study is to assess the health hazards due to environmental radiation sources in the city of Adapazari, one of the most important industrial cities of the country, Northwestern Turkey. For this purpose, natural radiation sources, external terrestrial radiations, cosmic radiations, and inhalation exposures have been investigated. The annual average external terrestrial radiation doses were determined as 0.08 and 0.35 mSv at outdoor and indoor atmospheres, respectively. The annual average cosmic radiation doses were found to be 0.08 and 0.05 mSv for directly ionising photon components and neutron components, respectively. The annual average inhalation exposure doses due to radon and thoron were obtained as 1.42 and 0.19 mSv, respectively, in the region. The annual average effective dose due to natural radiation sources was determined as a total of 2.35 mSv with the predetermined ingestion radiation dose. The lifetime cancer risk due to the background ionising radiations has been determined as 0.9×10−2 for the residents of the Adapazari city, with the average lifespan of 70 years. The results of the effective doses due to background radiation sources in the region and the worldwide averages were discussed.

Outdoor radioactivity and health risks in Balikesir, northwestern Turkey.

External irradiation from radionuclides naturally present in the environment or released from man-made practices or events is usually an important component of the exposure of human populations. These exposures derive primarily from gamma radiation arising from the decay of these radionuclides at locations outside the human body. The main objective of this study is to evaluate the radioactivity levels and health risks due to terrestrial radionuclides in the soil of Balikesir, one of the largest cities of the country, northwestern Turkey. For this purpose, activity concentrations of radionuclides in soil and outdoor gamma dose rates (terrestrial and cosmic) have been investigated in the city of Balikesir. In addition, maps for the radionuclide activity concentrations of soil and the outdoor gamma dose rate distributions have been plotted for the region. The average activities of radionuclides, (238)U, (232)Th, (40)K, (235)U and (137)Cs in the soil were determined to be 37.6 ± 10.8, 54.7 ± 15.1, 674.5 ± 203.2, 3.6 ± 1.6, 3.4 ± 2.2 Bq kg(-1), respectively, in the region. The average outdoor gamma dose rates due to terrestrial and cosmic radiations were found to be 78.5 ± 12.4 and 48.9 ± 5.8 nGy h(-1) with the total of 127.4 ± 18.9 nGy h(-1) in the region. Annual effective dose due to environmental outdoor gamma radiation exposures was determined to be 156.3 nSv. The mean estimated cancer risk values were found to be 0.063 × 10(-2) for the region using risk factors of ICRP 103. The results of the study were discussed with the studies done in other cities of Turkey and the worldwide averages.

A study of environmental radioactivity measurements for Cankiri, Turkey

This study is the first to assess the level of background radiation for the Cankiri province of Turkey. Indoor air radon concentrations were determined using Columbia Resin-39 nuclear track detectors and the average (222)Rn activity was found to be 44 Bq m(-3) (equivalent to an annual effective dose of 1.1 mSv). Measurements of gamma doses in outdoor air were performed using a portable plastic scintillation detector and the average gamma absorbed dose rate was found to be 8 μR h(-1) (corresponding to an annual effective dose of 87.7 μSv). Radionuclide activity concentrations in soil samples were measured through gamma-ray spectrometry and the average activities were determined as 17.7, 22.3, 357 and 4.1 Bq kg(-1) for the radionuclides (238)U, (232)Th, (40)K and (137)Cs, respectively. The average annual effective dose from the natural radioactivity sources ((238)U series, (232)Th series and (40)K) was calculated to be 44.4 μSv. Radioactivity levels of drinking water samples were carried out using a low-background proportional counter and the average gross alpha and beta activities were obtained as 0.25 and 0.26 Bq l(-1), respectively (equivalent to an annual effective dose of 184 μSv). The average radon concentrations in indoor air and the average radionuclide activities in soil were found to be lower than most Turkish cities while higher levels of outdoor gamma dose rate and water radioactivity were observed. The results of this study showed that the regions background radioactivity level differs considerably from the reported data for Turkish cities.

Natural and anthropogenic radionuclides in the granitic region of Kapidag peninsula, Western Anatolia, Turkey

Naturally occurring radionuclides of terrestrial origin (also called primordial radionuclides) are present in various degrees in all media in the environment. This study represents the reports on the natural and anthropogenic radionuclides in the Kapidag granitic region. For this purpose, activities of radionuclides in soil, beach sands and rocks of the region have been investigated to assess the radiological hazard of the natural radioactivity. The radium equivalent activities, the absorbed dose rates and the external hazard indexes have been calculated, and also in situ gamma dose rates have been measured in the region. The mean activities of (238)U, (232)Th and (40)K with the ranges were determined as 31.1±15.7 (12.1-71.9), 42.5±15.9 (19.7-94.9), 590.3±192.2 (184.7-892.5), in the soil, as 16.5±9.5 (4.9-40.8), 67.1±106.9 (18.5-433.0), 569.2±212.6 (162.0-821.1) in the sand and as 25.4±12.8 (4.8-50.7), 37.8±21.5 (4.5-96.7), and 592.4±285.5 (62.4-1121.6) Bq kg(-1) in the rocks, respectively. It was also observed that the average activities of (137)Cs were ranged 0-27.8 Bq kg(-1) in the soil and 0.6-3.8 Bq kg(-1) in the beach sands. The mean Ra(eq) activities of the rocks, sands and soil were found to be 125.1±59.5, 156.3±157.2 and 137.3±48.8 Bq kg(-1), respectively, lower than the recommended maximum value of 370 Bq kg(-1) with some exceptions. The maximum contributors to the total absorbed gamma dose rates in air were determined as (238)U (45%) for the beach sands, (238)U (40%) for the soil and (40)K (41%) for rocks. The average outdoor gamma dose rates for the soil due to terrestrial and cosmic radiations were found to be 64.6±22.7 and 47.1±9.6 nGy h(-1), respectively, with the total of 111.7±29.5 nGy h(-1) outdoor gamma exposure rate and the annual average effective outdoor gamma dose was calculated as 137±36.2 µSv for the region. The results of the study were discussed with similar studies in close regions and the worldwide averages.