Volume 11, No 3 International Journal of Radiation Research, July 2013 Determination of radioactivity levels and hazards of sediment and rock samples in İkizdere and Kaptanpaşa Valley, Turkey R. Keser 1* , F. Korkmaz Görür 2, İ. Alp 3, N.T. Okumuşoğlu 4 1Department of Physics, Faculty of Sciences and Arts, RTE University, 53100, Rize, Turkey 2Department of Physics, Faculty of Sciences and Arts, Abant İzzet Baysal University, 14280, Bolu, Turkey 3KTU, Faculty of Engineering, Mining Engineering, 61100, Trabzon-Turkey 4Department of Physics, Faculty of Sciences and Arts, Ondokuz Mayıs University, Samsun, Turkey ABSTRACT Background: The radioacvity levels in sediment and rock samples of İkizdere and Kaptanpaşa Valley have been determined. To our knowledge, there ► Original article seems to be no informaon about radioacvity level in the İkizdere and Kaptanpaşa Valley sediments and rocks so far. Materials and Methods: The average radium equivalent acvity (Ra eq ), the total absorbed dose rate (D), the external risk index (H ex ) and the annual effecve dose equivalent (AEDE) which will be defined later have been calculated and compared with the results in literature. Rock characterizaon was also invesgated using thin *Corresponding author: secon and X-ray diffracon (XRD) analysis. Also gross α and β acvity Dr. Recep Keser, concentraons were calculated for some rock samples. Results: Their Fax : +90 4642235376 radiological implicaons were also calculated and compared with the E-mail : internaonal recommended values. The gross α acvity is generally lower [email protected] than the corresponding gross β acvity for some rock samples. Rock Received: Dec. 2011 characterizaon was also invesgated using thin secon and XRD analysis. Accepted: April 2012 Conclusion: This study can be used as a baseline for future invesgaons and Downloaded from ijrr.com at 0:58 +0330 on Friday October 8th 2021 the data obtained in this study may be useful for natural radioacvity Int. J. Radiat. Res., July 2013; mapping. It seems necessary to determine the radioacvity concentraons in 11(3): 155-165 sediments and rock of other parts of Turkey. The results may also be used as a reference data for monitoring possible radioacvity polluons in future. Keywords: Sediment, rock, natural radioactivity, Đkizdere and Kaptanpaşa Valley, XRD. ferred to man through food chain or inhalations, INTRODUCTION while the extraterrestrial radiation originates from outer space as primary cosmic rays (1-4) . The knowledge of radionuclides distribution In terms of natural radioactivity, granites and radiation levels in the environment is exhibit an enhanced elemental concentration of important for assessing the effects of radiation uranium (U) and thorium (Th) compared to the exposure due to both terrestrial and extraterres- very low abundance of these elements observed trial sources. Natural background radiation is of in the mantle and the crust of the Earth. terrestrial and extraterrestrial origin. Terrestrial Geologists provide an explanation of this radiation is due to radioactive nuclides present behavior in the course of partial melting and in varying amounts in soils, building materials, fractional crystallization of magma, which water, rocks and atmosphere. Some of these enables U and Th to be concentrated in the radionuclides from these sources are trans- liquid phase and become incorporated into the Keser et al. / Radioactivity levels of sediment and rock samples in Turkey more silica-rich products. For that reason, fog in almost every season of the year. The igneous rocks of granitic composition are highest and lowest temperatures were recorded strongly enriched in U and Th (on an average 5 to be 38 and -7 ºC, respectively, with the mean ppm of U and 15 ppm of Th), compared to the value of 15 ºC. There are different rock Earth’s crust (average 1.8 ppm for U and 7.2 structures having different ages and lithological ppm for Th) (1) , the upper continental crust features. As shown in Ligure 1, the study area are (average 2.7 ppm for U and 10.5 ppm for Th) (2) consists of mainly volcanic rocks such as basalts, and rocks of basaltic or ultramaLic composition andesite and granites (6) . (0.1 ppm of U and 0.2 ppm of Th) (1, 3-5) . The aim of this study is to determine natural IJkizdere Valley is on the river bank, 56 km (238 U, 232 Th, 40 K) and artiLicial ( 137 Cs) radioactivi- from the city of Rize on the road to Erzurum. It is ty levels in sediments and rocks collected from discharged to the Eastern Black Sea near IJyidere different points in IJkizdere and Kaptanpaşa town in the west of Rize. IJkizdere Valley stand Valley in Rize province of Turkey. Also, Ra eq , D, between 40° 42′ 37″ north latitudes, Hex , and AEDE which will be deLined later have 40° 36′ 55″ east longitudes. The Kaptanpaşa been calculated and compared with the results Valley originates from the slopes of Kackar in literature. Rock characterization was also Mountains and is discharged to the Eastern investigated using thin section and XRD analysis. Black Sea, near Çayeli town in the east of Rize. Also gross α and β activity concentrations were Kaptanpaşa Valley stands between calculated for some rock samples. The results of 40° 45′ 0″ north latitudes, 41° 4′ 0″ east longi- this study will provide background data on the tudes. In the Valley, rainfall is mostly observed natural and artiLicial radioactive isotopes and during winter and fall. These places, especially environmental pollution. the parts having 1500 m height are covered with Downloaded from ijrr.com at 0:58 +0330 on Friday October 8th 2021 Figure 1. Locaon of sampling sites the Rize Province, Turkey. Int. J. Radiat. Res., Vol. 11 No. 3, July 2013 156 Keser et al. / Radioactivity levels of sediment and rock samples in Turkey MATERIALS AND METHODS and analysis system. The detector had coaxial closed–facing geometry with the following speciLications: resolution full width half Sample collection and preparation maximum (FWHM) at 122 keV 57 Co was 1.00 In this study research area was divided into keV and at 1.33MeV 60 Co was 1.90 keV. The two regions IJkizdere and Kaptanpaşa. The detector was shielded by a cylindrical lead sampling stations are given in Ligure 1. The shield, which had average thickness of 10 cm to sediment (at 0-15 cm depth level) and rock reduce the background due to the cosmic rays samples were collected along the IJkizdere and and the radiation nearby the system. EfLiciency Kaptanpaşa Valley area in the summer of 2007. of the detector was determined with a 152 Eu The sediment samples were taken just near the 152 river bank of about 10–100 cm. The sediment source of known activity. Eu source has been samples were homogenized in situ, and this sand widely used for calibration and efLiciency mixture, weighing approximately 20 kg, was determination due to their large range of considered representative of the sampling site. energies (122, 244, 344, 411, 443, 779, 964, The samples were cleaned with warm water, 1112 and 1408 keV) with emission probabilities (7, 8) dried in the laboratory. In the case of grain size of 3-29 % . An ideal measuring geometry of study, samples were sieved after drying into Live cylindrical source (homogeneously distributed classes of particle size, namely <250, 250-300, activity with constant volume and distance) was 300-600, 600-850 and 850-1000 mm. The rock placed coaxially with the detector for the samples were taken from sampling locations as efLiciency determination and the same proce- blocks cores. Eighteen rock samples were dure applied for the sample measurements. collected from a quarry factory available in The samples were sealed and stored in a IJkizdere (Rock1-Rock6) and Kaptanpaşa (Rock 7 tight container to prevent the escape of -Rock18) areas. All the rock samples are of Gran- radiogenic gases 222 Rn and 220 Rn, and to allow ite type. The samples, each about 1 kg in weight, the attainment of radioactive equilibrium in the were crushed, homogenized and sieved to about decay chain. After attainment of secular equilib- 100 mesh by a crushing machine. The samples rium between 232 Th, 238 U and their daughter were then placed for drying at 105 0C for 24 h to products, the samples were subjected to gamma ensure that moisture is completely removed. -ray spectrometric analysis. Natural radionu- Downloaded from ijrr.com at 0:58 +0330 on Friday October 8th 2021 About 250 g of sample material were used for clides of relevance for this work are mainly the measurements of each granite sample. γ-ray emitting nuclei in the decay series of 232 Th The sediment and rock samples were then and 238 U, and single occurring 40 K. While 40 K can weighed and transferred to Marinelli beakers of be measured directly by its own γ-rays, 232 Th 1000 ml volume. The samples were kept for 4 and 238 U are not directly γ-ray emitters, but it is weeks before analysis under airtight conditions possible to measure γ-rays of their decay to allow secular equilibrium between thorium products. Decay products for 238 U ( 214 Pb: 295 and radium and their decay products. and 352 keV; and 214 Bi: 609 keV) and 232 Th Rock characterization was also investigated (228 Ac: 338, and 911 keV; 212 Pb: 239 keV; 212 Bi: using thin section and XRD analysis by X-ray 727 keV; and 208 Tl: 583 keV) were used by diffraction study using XRD, RIGAKU D-MAX assuming the decay series to be in secular difractometer, CoKα. equilibrium (7) . Weighted averages of several decay products were used to estimate activity Experimental method for γ- spectroscopy concentrations of 238 U and 232 Th.