https://hdl.handle.net/20.500.12809/8880 2026-04-07T01:57:42Z 2026-04-07T01:57:42Z Altıkulaç, Aydan Turhan, Şeref https://hdl.handle.net/20.500.12809/10823 2023-08-01T10:32:09Z 2023-01-01T00:00:00Z

Assessment of the Levels of Potentially Toxic Elements Contained in Natural Bentonites Collected from Quarries in Turkey Altıkulaç, Aydan; Turhan, Şeref Potentially toxic elements (PTEs) are an important type of pollutant, causing constant and far-reaching concerns around the world due to their increase in the mining process. Bentonite formed by the alteration of glass-rich volcanic rocks is a smectite clay consisting mostly of montmorillonite. Bentonite is an important mineral used in a wide range of applications in many fields such as oil and gas, agriculture, food, pharmacological, cosmetic, and construction industries due to its unique qualities. Given the widespread distribution of bentonite in nature and its use in a wide variety of consumer products, it is inevitable that the general population will be exposed to PTEs contained in bentonites. In this study, concentrations of PTEs in 69 bentonite samples collected from quarries located in different geographical regions of Turkey were analyzed by an energy-dispersive X-ray fluorescence spectrometric method. The average concentrations of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Zr, and Pb in bentonite samples were found to be 3510, 95, 129, 741, 30,569, 67, 168, 25, 62, 9, 173, and 28 mg/kg dry weight, respectively. Results of the enrichment factor relating to Earth’s crust average indicated moderate enrichment with Cr, Ni, and Pb and significant enrichment with Co and As.

2023-01-01T00:00:00Z Altıkulaç, Aydan https://hdl.handle.net/20.500.12809/10395 2022-11-22T06:57:11Z 2022-01-01T00:00:00Z

Investigation of Radiological and Chemical Contents of Bauxite Ore Extracted in Turkey Altıkulaç, Aydan In this study, which consists of two parts, the radiological and chemical content of bauxite ore was investigated. Gamma-ray spectrometry was used in the first part of the study to determine the activity concentrations of natural radionuclides in samples taken from bauxite deposits in Turkey. The measured activity concentrations of 226Ra, 232Th, and 40K varied from 12.1 ± 2.5 to 132.6 ± 11.4 Bq kg-1 with a mean of 78.4 ± 8.3 Bq kg-1, 6.5 ± 0.5 to 97.3 ± 9.9 Bq kg-1 with a mean of 64.5 ± 5.9 Bq kg-1, and 5.1 ± 0.0 to 356.4 ± 40.1 Bq kg-1 with a mean of 52.6 ± 5 Bq kg-1, respectively. The calculated mean radium equivalent activity value is 177.4 Bq kg-1, the mean gamma dose rate absorbed in the air is 78.8 nGy h-1, the mean corresponding annual effective dose value is 96.6 μSv y-1, and the mean lifetime risk of cancer is 3.85 × 10-4. The chemical content of the bauxite samples was determined in the second part of the study using X-ray fluorescence spectrometry (XRF). For which sectors in the industry the existing bauxite deposits in Turkey can be used was investigated based on this information.

2022-01-01T00:00:00Z Altıkulaç, Aydan Kurnaz, Aslı Turhan, Şeref Kutucu, Metehan https://hdl.handle.net/20.500.12809/10328 2022-10-05T13:36:54Z 2022-01-01T00:00:00Z

Natural Radionuclides in Bottled Mineral Waters Consumed in Turkey and Their Contribution to Radiation Dose Altıkulaç, Aydan; Kurnaz, Aslı; Turhan, Şeref; Kutucu, Metehan Bottled natural mineral water (BMW) consumption in Turkey is increasing every year. Depending on the local geology from which the water is extracted, BMW could be enhanced with natural radionuclides. In this study, the activity concentrations of natural radionuclides in 58 BMW samples of 25 different brands marketed in Turkey were measured using a γ-ray spectrometer with high-purity germanium (HPGe) detector. The average activity concentrations of 226Ra, 228Ra, and 40K in BMW samples were found as 0.4, 0.5, and 4.3 Bq/L, respectively. The activity concentrations of 228Ra exceeded the WHO-recommended maximum permissible limit of 0.1 Bq/L for drinking water. The annual effective dose (AED) and excess lifetime cancer risk (LCR) caused by the ingestion of each BMW sample were estimated for adults to assess radiological risks using two different scenarios based on BMW consumption rates (150 and 13 L/y). All estimated total AEDs, except for two samples, were below the guidance dose level of 100 μSv/y recommended by the World Health Organization (WHO) and Turkish regulations for drinking water. For all BMW brands, 228Ra was found as the main contributor to the AEDs. The LCR values were lower than the acceptable value of 10-3 for radiological risks.

2022-01-01T00:00:00Z Altıkulaç, Aydan Kurnaz, Aslı Turhan, Şeref Metin, Onur Duran, Celalettin https://hdl.handle.net/20.500.12809/10286 2022-09-16T12:17:58Z 2022-01-01T00:00:00Z

Evaluation of terrestrial radionuclide levels and concomitant radiological risks of bentonites used in many industries Altıkulaç, Aydan; Kurnaz, Aslı; Turhan, Şeref; Metin, Onur; Duran, Celalettin Bentonite is a soft, porous, easily shaped, and absorbent material rich in aluminum, sodium, and potassium. Bentonite is a mineral widely utilized as drilling mud, ore pelletizing, absorbent/adsorbent, bleaching agent, water impedance, coating, and raw material in various industries. In this study, radiometric measurements of 90 bentonite samples collected from 21 quarries in Turkey were performed using gamma-ray spectrometry. The radiological hazards caused by indoor exposure to adults due to the utilization of bentonites as raw materials in the construction industry and outdoor external exposures to quarry workers were evaluated by estimating the activity concentration index, annual effective doses, and lifetime cancer risk. The average activity concentrations of Ra-226, Th-232 and K-40 measured in bentonite samples were found as (50 +/- 5) Bq/kg, (76 +/- 4) Bq/kg and (373 +/- 19) Bq/kg, respectively. The evaluation results reveal that the bentonites examined could be safely utilized as raw materials.

2022-01-01T00:00:00Z