U. Cevik

Determination of indoor radon and soil radioactivity levels in Giresun, Turkey

Indoor radon survey and gamma activity measurements in soil samples were carried out in the Giresun province (Northeastern Turkey). The result of analysis of variance showed a relationship between indoor radon and radium content in soil (R(2)=0.54). It was found that indoor radon activity concentration ranged from 52 to 360 Bq m(-3) with an average value of 130 Bq m(-3). A model built by BEIR VI was used to predict the number of lung cancer deaths due to indoor radon exposure. It was found that indoor radon is responsible for 8% of all lung cancer deaths occurring in this province. (137)Cs activity concentration was measured 21 years after the Chernobyl accident. The results showed that (137)Cs activity concentration ranged from 41 to 1304 Bq kg(-1) with an average value of 307 Bq kg(-1). The indoor radon results and the geology of the studied area were discussed. Annual effective doses to the both radionuclides of natural origin and (137)Cs were estimated.

Radiological maps for Trabzon, Turkey

The activity concentrations and absorbed gamma dose rates due to primordial radionuclides and (137)Cs have been ascertained in 222 soil samples in 18 counties of the Trabzon province of Turkey using a HPGe detector. The mean activity concentrations of (238)U, (232)Th, (40)K and (137)Cs in soil samples were 41, 35, 437 and 21 Bq kg(-1), respectively. Based on the measured concentrations of these radionuclides, the mean absorbed gamma dose in air was calculated as 59 nGy h(-1) and hence, the mean annual effective dose due to terrestrial gamma radiation was calculated as 72 μSv y(-1). In addition, outdoor in situ gamma dose rate (D) measurements were performed in the same 222 locations using a portable NaI detector and the annual effective dose was calculated to be 66 μSv y(-1) from these results. The results presented in this study are compared with other parts of Turkey. Radiological maps of the Trabzon province were composed using the results obtained from the study.

Environmental radioactivity assessment for Bayburt, Turkey

This study assesses the results of environmental radioactivity measurements for Bayburt Province in the Eastern Black Sea area of Turkey. Using gamma-ray spectrometry, activity concentrations of the natural radionuclides (226)Ra, (232)Th and (40)K and a fission product (137)Cs were investigated in soil samples. The activity concentrations of (226)Ra, (232)Th and (40)K in various building materials such as sand, cement and marble and in drinking waters were determined. The activity concentrations vary from 16 to 54 Bq kg(-1) for (226)Ra, from 10 to 21 Bq kg(-1) for (232)Th and from 113 to 542 Bq kg(-1) for (40)K in building materials. The mean specific activity concentrations of (226)Ra, (232)Th and (40)K in drinking waters were 93, 30 and 504 mBq l(-1), respectively. The concentrations of gross alpha and beta radioactivity in drinking water samples collected from four different sampling stations have been determined. The results show that the gross alpha and beta activities are lower than the screening levels given by the World Health Organization (WHO), which are a maximum contaminant level of 0.5 Bq l(-1) and 1.0 Bq l(-1) gross alpha and beta radioactivity, respectively, in drinking water. Indoor radon measurements were made in 44 dwellings in Bayburt by using Cr-39 detectors. Radon concentrations in dwellings in Bayburt varied from 17 to 125 Bq m(-3) and the average value was 56 Bq m(-3). The results obtained in this study indicate that the region has a background radiation level that is within the typical natural range and shows no significant departures from other parts of the country.

Radiological and chemical assessment of phosphate rocks in some countries

In this study, the radiological, structural and chemical characterizations of Mardin-Mazidaği phosphate rock, which is an important phosphate fertilizer source in Turkey were investigated and compared to those of several different phosphate rocks of Tunisia, Egypt, Morocco, Algeria and Syria using gamma spectrometry, X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurement techniques. Elemental analysis results of phosphate samples showed that they were mainly composed of CaO, P(2)O(5), SiO(2), Al(2)O(3), SO(3) and Fe(2)O(3). Elemental concentrations of U and Th were calculated using (226)Ra and (232)Th activity concentrations, respectively. As a result of XRD analysis, the main peaks of the samples were found to be Fluorapatite (Ca(5)(PO(4))(3)F). The radioactivity concentration levels for (226)Ra, (232)Th and (40)K in all phosphate samples ranged from 250 to 1029 Bq kg(-1) with a mean of 535 Bq kg(-1), from 5 to 50 Bq kg(-1) with a mean of 20 Bq kg(-1) and from 117 to 186 Bq kg(-1) with a mean of 148 Bq kg(-1), respectively. The computed values of annual effective doses ranged from 0.17 to 0.59 mSv, with a mean value of 0.33 mSv, which is lower than the recommended limit of 1 mSv y(-1) by the International Commission on Radiological Protection.

Assessment of natural radioactivity of sand used in Turkey

The natural radioactivity due to the presence of (226)Ra, (232)Th and (40)K in sand samples used as building materials in Turkey was measured by gamma spectrometry. The measured activity in the sand samples ranged from 17 to 97 Bq kg(-1), 10 to 133 Bq kg(-1) and 116 to 955 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The concentrations of these natural radionuclides were compared with the reported data for other countries. The radium equivalent activity (Ra(eq)), the external hazard index (H(ex)), the internal hazard index (H(in)), the indoor absorbed dose rate in air and the annual effective dose rate were evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. The Ra(eq) values of sand samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv yr(-1). This study shows that the measured sand samples do not pose any significant source of radiation hazard and are safe for use in building materials. Moreover, the experimental mass attenuation coefficients (mu/rho) of seven different sand samples were determined in the energy range 80-1332 keV photons by using the gamma ray transmission method. Experimental values of mass attenuation coefficient were compared with theoretical values obtained using the program XCOM. The calculated values and the experimental results of this work and the other results in the literature are found to be in good agreement. Chemical and structural analyses (XRD) of the sand samples were also undertaken.

Calculation of radiation attenuation coefficients, effective atomic numbers and electron densities for some building materials

Some building materials, regularly used in Turkey, such as sand, cement, gas concrete (lightweight, aerated concrete), tile and brick, have been investigated in terms of mass attenuation coefficient (μ/ρ), effective atomic, numbers (Z(eff)), effective electron densities (N(e)) and photon interaction cross section (σ(a)) at 14 different energies from 81- to 1332-keV gamma-ray energies. The gamma rays were detected by using gamma-ray spectroscopy, a High Purity Germanium (HPGe) detector. The elemental compositions of samples were analysed using an energy dispersive X-ray fluorescence spectrometer. Mass attenuation coefficients of these samples have been compared with tabulations based upon the results of WinXcom. The theoretical mass attenuation coefficients were estimated using the mixture rule and the experimental values of investigated parameters were compared with the calculated values. The agreement of measured values of mass attenuation coefficient, effective atomic numbers, effective electron densities and photon interaction cross section with the theory has been found to be quite satisfactory.

Radiological characterisation of Artvin and Ardahan provinces of Turkey

Indoor radon concentration measurements were carried out and corresponding annual effective doses due to exposure to indoor radon were determined in Artvin and Ardahan provinces located in the eastern part of Turkey. The measurements were performed for four seasons in order to determine the seasonal fluctuations mostly observed in indoor environments. Indoor radon concentration values were observed to range from 21 to 321 Bq m⁻³ for the Artvin province and from 53 to 736 Bq m⁻³ for the Ardahan province. It was observed that minimum indoor radon concentration values were obtained in summer, while the highest ones were observed in winter. Indoor radon concentration values of the current study were compared with those of other provinces in Turkey. As elevated indoor radon concentrations are mostly correlated with high ²³⁸U activity concentrations in soil, a total of 57 and 33 soil samples were collected from the Artvin and Ardahan provinces, respectively, to determine ²³⁸U activity concentration as well as the concentration of ²³²Th and ⁴⁰K--naturally occurring radionuclides. It was also observed that soil samples collected from the study areas contained ¹³⁷Cs as an artificial radionuclide.

Gamma ray concentrations in soil and building materials in Ordu, Turkey

The city of Ordu is in the Eastern Black Sea region of Turkey with a population of approximately 716,000. Presently there is no information available about radioactivity levels in Ordu soil and building materials. For this reason, activity concentrations in soil and building material samples collected from different sampling stations in Ordu were measured using gamma-ray spectrometry. In addition to natural radionuclides, 137Cs was detected in the soil samples and the possible origins of this radionuclide were discussed. The activity concentrations of soil samples ranged from 13.4 to 151.7 Bq kg−1 for 226Ra, from 14.3 to 98.5 Bq kg−1 for 232Th, from 303 to 1107 Bq kg−1 for 40K and from 67.4 to 275.3 Bq kg−1 for 137Cs. The mean concentrations of 226Ra, 232Th and 40K in selected building materials were 34.5, 26.9 and 378.4 Bq kg−1, respectively. The results were compared with the reported data from different works. From the measurements, radium equivalent activity, terrestrial absorbed dose, annual effective dose rate, external hazard indices and internal hazard indices were calculated, and were found to be within the acceptable limits. The data presented in this study might be useful as a baseline data for future estimations of a populations exposure.

A study of environmental radioactivity measurements in the Samsun province, Turkey

This study was concerned with the measurement of natural and artificial radionuclides in soil samples and indoor radon concentrations in the Samsun province, Turkey. In soil samples, the values of individual mean activity of (226)Ra, (232)Th, (40)K and (137)Cs radionuclides were found to be 31, 22, 341 and 16 Bq kg(-1), respectively. The radiological parameters, such as the absorbed dose rate in air, the annual effective dose (AED) and excess lifetime cancer risk, were calculated. Indoor radon measurements were carried out with CR-39-based radon dosemeters at 127 dwellings in the Samsun province. The mean annual (222)Rn activity was found to be 106 Bq m(-3) (equivalent to an AED of 1.88 mSv). The seasonal variation of (222)Rn activity shows that maximum levels are observed in the winter, while minimum levels are observed in the summer. The mean lifetime fatality risk for the studied area was estimated at 1.45×10(-4). The results obtained did not significantly differ from those obtained in other parts of the country.

Radiological Characterization of Natural Spring Waters in Eastern Black Sea Region, Turkey

The activity concentrations of 226Ra, 232Th, 40K and 137Cs radionuclides in the natural spring waters of the Eastern Black Sea region of Turkey were measured using gamma-ray spectrometry. The mean specific activities of the radionuclides in the samples were 52, 23, 379 and 24 mBq/L–1, respectively. The overall annual effective dose from all measured radionuclides was much below the World Health Organization (WHO, Geneva Switzerland) recommended reference level of 0.1 mSv.y−1 for drinking water consumption. Gross α and β activities ranged from 1 to 188 mBq/L−1 and from 3 to 91 mBq/L−1, respectively. Concentrations of elements in waters were also measured by inductively coupled plasma-optical emission spectrometry. An analysis of variance and Pearson correlation analysis were performed for radioactivity and elemental analysis. This study provides background values of investigated nucleotides in the water from the region, which could also be useful in forensic investigations to distinguish potential contributions from point pollution sources.