Cafer Mert Yeşilkanat

Evaluation of Outdoor Gamma Dose Rate and Cancer Risk in Artvin Province, Turkey

ABSTRACT In this study, we measured environmental outdoor gamma dose rates (terrestrial and cosmic) in 204 stations across the province of Artvin. The average outdoor gamma dose rate for the province of Artvin was found to be 174.81 nGy/h. The radiological map of Artvin was drawn with the help of measured outdoor gamma dose rates. Annual effective dose equivalent and lifetime cancer risk values were figured up for the adults in Artvin province by using measured outdoor gamma dose rates. The average annual dose equivalent and excess lifetime cancer risk were 214.5 μSv/y and 7.5 × 10−4, respectively. The values acquired were compared with the similar studies done around the world. The average annual effective dose equivalent and excess lifetime cancer risk were found to be approximately three times higher than the world average.

Investigation of Cs-137 and K-40 activities of natural spring waters of the Eastern Black Sea Region, Turkey

The activity concentrations of Cs-137 and K-40 radio nuclides in the natural spring waters of the Eastern Black Sea region of Turkey were measured using gamma-ray spectrometry. Annual effective dose equivalents of Cs-137 and K-40 in babies, children and adults were calculated from the obtained measurements. These results were compared with other studies and the limit values of World Health Organization. The activity concentrations were calculated and kriging-geostatistical method was used to plot the obtained data on the radioactive maps of Eastern Black Sea Region. Frequency distributions of the water samples for each province were determined. This study provides background values of investigated Cs-137 and K-40 in the water from the region, which could, also, be useful in forensic investigations to distinguish potential contributions from point pollution sources.

Interpolated mapping and investigation of environmental radioactivity levels in soils and mushrooms in the Middle Black Sea Region of Turkey

ABSTRACT The activity concentration of natural (238U, 232Th, and 40K) and artificial (137Cs) radionuclides was determined in 50 samples (obtained from the same station) from various species of mushrooms and soil collected from the Middle Black Sea Region (Turkey). The activities of 238U, 232Th, 40K, and 137Cs were found as 84 ± 16, 45 ± 14, 570 ± 28, and 64 ± 6 Bq kg–1 (dry weight), respectively, in the mushroom samples and as 51 ± 6, 41 ± 6, 201 ± 11, and 44 ± 4 Bq kg–1, respectively, in the soil samples for the entire area of study. The results of all radionuclide activity measurements, except those of 238U and 232Th in the mushroom samples, are consistent with previous studies. In the soil samples, the mean values of 238U and 232Th are above the world mean, and the activity mean of 40K is below the world mean. Finally, the activity estimation was made with both the soil and mushroom samples for unmeasured points within the study area by using the ordinary kriging method. Radiological distribution maps were generated.

Spatial interpolation and radiological mapping of ambient gamma dose rate by using artificial neural networks and fuzzy logic methods

The aim of this study was to determine spatial risk dispersion of ambient gamma dose rate (AGDR) by using both artificial neural network (ANN) and fuzzy logic (FL) methods, compare the performances of methods, make dose estimations for intermediate stations with no previous measurements and create dose rate risk maps of the study area. In order to determine the dose distribution by using artificial neural networks, two main networks and five different network structures were used; feed forward ANN; Multi-layer perceptron (MLP), Radial basis functional neural network (RBFNN), Quantile regression neural network (QRNN) and recurrent ANN; Jordan networks (JN), Elman networks (EN). In the evaluation of estimation performance obtained for the test data, all models appear to give similar results. According to the cross-validation results obtained for explaining AGDR distribution, Pearsons r coefficients were calculated as 0.94, 0.91, 0.89, 0.91, 0.91 and 0.92 and RMSE values were calculated as 34.78, 43.28, 63.92, 44.86, 46.77 and 37.92 for MLP, RBFNN, QRNN, JN, EN and FL, respectively. In addition, spatial risk maps showing distributions of AGDR of the study area were created by all models and results were compared with geological, topological and soil structure.