https://hdl.handle.net/11436/903 2026-07-31T04:29:04Z 2026-07-31T04:29:04Z Kırış, Erkan https://hdl.handle.net/11436/10975 2025-08-21T11:57:21Z 2025-01-01T00:00:00Z

Quantitative analysis and exposure assessment of heavy metals in roasted coffee consumed in Turkey using ICP Kırış, Erkan The heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were quantified in 26 roasted coffee samples (19 Arabica and 7 Robusta) consumed in Turkey using ICP-OES. Cd and Pb were not detected in any sample. Cr was found only in Robusta samples, with a mean concentration of 0.58 mg/kg. The average concentrations of Cu, Fe, Mn, Ni, and Zn were 12.34 and 13.10 mg/kg, 13.67 and 14.69 mg/kg, 23.37 and 11.66 mg/kg, 0.04 and 1.17 mg/kg, and 8.31 and 7.19 mg/kg in Arabica and Robusta coffee samples, respectively. The heavy metal concentrations were compared with international limits and literature values. To assess the human health risk posed by heavy metals in the coffee samples, the estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) were calculated based on average coffee consumption. All the EDI values were below the oral reference doses (RfDs), and both the HQ and HI values were less than 1, indicating no significant non-carcinogenic health risk associated with coffee consumption. Descriptive statistics summarized heavy metal levels, while inferential statistical tests evaluated differences among the coffee-growing regions and between the coffee bean species.

2025-01-01T00:00:00Z Makolli, Sami Dizman, Serdar Hodolli, Gezim Kadiri, Sehad Cadraku, Hazir https://hdl.handle.net/11436/10965 2025-08-21T07:38:53Z 2025-01-01T00:00:00Z

Radiological assessment of soil and rock samples from Stubla Village, Kosovo Makolli, Sami; Dizman, Serdar; Hodolli, Gezim; Kadiri, Sehad; Cadraku, Hazir Background: This study represents a thorough exploration of the radioactivity levels in soil and rock samples collected from Stubla Village, Kosovo. The main aim is to evaluate the potential hazards and risks associated with using these materials in construction, and this is a common practice among residents when building homes. Materials and Methods: Gamma spectrometry was employed to analyze 19 soil samples and seven rock samples, followed by the calculation of the primary radiological parameters. Results and Discussion: The activity concentration of 226Ra, 232Th, 40K, and 137Cs was determined in soil samples (95.84±67.5, 75.51±35.5, 12.87±23.5, and 738.87±186.7 Bq/kg, respectively) and natural rock samples (199.8±190.2, 147.0±14.3, 967.1±47.4 Bq/kg, and not detected, respectively). Almost all the calculated health radiological hazard factors exceeded the recommended limits by international professional organizations. Conclusion: The rocks from this specific region are unsuitable for construction work due to their high radioactivity levels. This emphasizes potential environmental and health risks. The findings underscore the importance of implementing alternative materials for construction. Additionally, further investigations into radioactivity risks in the area under study should be conducted, such as assessing radioactivity concentrations in drinking water, food, and indoor radon exposures, to ensure the safety and well-being of the community and the environment.

2025-01-01T00:00:00Z Kabamaklı, Beyhan Akçay, Nilay https://hdl.handle.net/11436/10957 2025-08-21T06:40:54Z 2025-01-01T00:00:00Z

Determination of 226Ra, 232Th, 40K, and 137Cs activity concentrations in tea leaf samples from Rize, Türkiye, 30 years after the Chernobyl accident, and associated radiological risk parameters Kabamaklı, Beyhan; Akçay, Nilay 137Cs, released into the atmosphere in large quantities following the Chernobyl accident, is one of the most hazardous radionuclides, as it can persist in the environment for a long time due to its physical half-life of 30 years. Along with 137Cs, 226Ra, 232Th, and 40K which are naturally occurring radioactive elements, can enter the human body through ingestion, acting as internal sources of radiation and potentially causing adverse health effects in the long term. Rize is one of the most important tea-growing regions in the world and was affected by the Chernobyl accident in 1986. This study aimed to determine the activity concentrations of 226Ra, 232Th, 40K, and 137Cs in tea leaf samples collected from Rize, Türkiye, 30 years after the Chernobyl accident, and to estimate the associated radiological risk parameters, such as annual effective ingestion dose and excess lifetime cancer risk for consumers. Radioactivity analyses of tea leaf samples collected from 36 different stations were carried out with a high purity gamma spectroscopy system. The mean activity concentrations of both 226Ra and 232Th were calculated as 3.3 Bq/kg. The mean 137Cs and 40K activity concentrations were determined to be 10.5 Bq/kg, and 373.7 Bq/kg, respectively. These values were compared to the results obtained from similar studies conducted in Türkiye and other countries. Additionally, the mean 137Cs activity concentration was found to be significantly lower than the permitted limit of 1000 Bq/kg for foods set by the ICRP (2005), EU (2016), and FAO (2011). Based on the detected 226Ra, 232Th, and 137Cs activity concentrations, the highest total annual effective ingestion dose for the samples was estimated as 14.9 µSv/y. This value did not exceed the global annual average ingestion dose from the ingestion of terrestrial radionuclides to be 290 µSv/y reported by the UNSCEAR (2008). The total excess lifetime cancer risk values for the samples ranged from 0.08 × 10−5 to 2.88 × 10−5, and were found to be considerably lower than the limit of 2.5 × 10−3, as reported by the ICRP (1991). Based on these findings, it can be stated that the analyzed tea leaf samples in this study were radiologically safe and did not pose any carcinogenic risk to public health.

2025-01-01T00:00:00Z Çelik, Necati Akçay, Nilay Çevik, Uğur https://hdl.handle.net/11436/10929 2025-08-15T12:05:42Z 2025-01-01T00:00:00Z

A comparative study of 137Cs dose factors for constant and depth-dependent soil densities Çelik, Necati; Akçay, Nilay; Çevik, Uğur Accurate assessment of external radiation dose rates from 137Cs is essential for evaluating radiological risk in environmental and occupational settings. This study refines dose conversion coefficient calculations by incorporating depth-dependent soil density and addressing limitations in conventional methods that assume constant soil density. We calculated dose conversion coefficients for 137Cs in soil, considering both exponential and Gaussian distributions of activity concentration. Using two models, one with constant density and another with variable density as a function of depth, we compared dose rates to quantify the effect of soil density variations. Results indicate that dose rates are consistently higher when depth-dependent density is applied. The effect is more pronounced when 137Cs activity is distributed over larger depths (i.e., greater relaxation lengths) or when broader Gaussian distributions are considered. This suggests that assuming constant soil density may lead to underestimations of dose rates, especially in heterogeneous or compacted soils. Our findings emphasize the importance of accounting for density variability in dose calculations to enhance radiological risk assessments for areas contaminated with 137Cs.

2025-01-01T00:00:00Z