Necati Çelik

Assessment of Radiological Levels at Schools in Trabzon, Turkey

In this study, a survey on environmental radioactivity in 16 high schools located in north eastern region of Turkey (the black sea region, province of Trabzon) was carried out. Indoor air radon (222Rn) concentrations were measured in spring and autumn 2008 seasons using LR115 solid state nuclear track detectors and gamma radioactivity levels were measured using an HPGe gamma ray detector. It was seen that mean radon activity concentrations in schools ranged from 31 to 157 Bq/m3 for spring season and from 38 to 114 Bq/m3 for autumn season. The mean gamma activity concentrations in located areas of schools are between 18–52, 21–59, 11–97 and 265–759 Bq/kg for 226Ra, 232Th, 137Cs and 40K, respectively. The annual effective doses of students and staff received due to radon and locations’ gamma radioactivity levels are calculated.

Radioactivity measurements and risk assessments of spa waters in some areas in Turkey

ABSTRACT The current study presents the results of the activity of radionuclides in spa waters, and evaluates their radiological influences on the population consuming these waters in the Central and Eastern Black Sea regions of Turkey. Since these waters are used for therapy and consumption purposes unconsciously, their radiological impact on the people was computed by taking into consideration the annual intake through ingestion of 226Ra, 232Th, 40K, 137Cs and 222Rn. The mean activities were estimated to be 11.35 for gross alpha, 6.23 for gross beta, 2.96 for 226Ra, 0.42 for 232Th, 0.069 for 137Cs, 0.19 for 40K, and 267 Bq L–1 for 222Rn, respectively. The estimated effective doses from spa water were found to be 49.77 µSv a–1 (226Ra), 5.95 µSv a–1 (232Th), 0.07 µSv a–1 (137Cs), 0.83 µSv a–1 (40K) and 56.03 µSv a–1 (222Rn). These values were evaluated and compared with related verified values from literature. Also, physico-chemical characterizations of spa water samples considered in the current study were investigated. This study would be useful for consumers and official authorities for the assessment of radiation exposure risk due to usage of the considered spa waters.

Indoor radon and gamma spectrometric measurements for the Erzincan Basin on North Anatolian Fault Zone, Turkey

Indoor radon and soil radioactivity levels were determined for Erzincan province in Turkey. Indoor radon concentrations were determined in 89 dwellings using CR-39 passive Solid State Nuclear Track Detectors (SSNTDs) for four seasons. The mean annual 222Rn activity concentration was found to be 119 Bq.m−3. In the winter season, indoor radon concentrations showed the highest values while the lowest values were observed in the summer season. A model was used to predict the number of lung cancer incidences due to inhalation of radon. The findings have indicated that radon is responsible for 13% of lung cancer incidences occurring in the Erzincan province. Since indoor radon concentration correlates with 226Ra content in soil beneath the dwellings, soil samples were collected near the houses where indoor radon measurements were performed in order to seek a correlation. The 226Ra, 232Th, 40K and 137Cs activity concentration values were 52, 26, 649 and 9 Bq.kg−1, respectively. The annual effective dose due to naturally occurring radionuclides was around 82 µSv.y−1 which is higher than the world average value of 70 µSv.y−1. The results of the present study are expected to be a useful baseline data for future studies.

Monte Carlo modelling of human body for dose conversion coefficients of 137Cs in soil of the Eastern Black Sea region of Turkey.

Absorbed dose conversion coefficients for a human body standing on the soil surface were calculated for 137Cs in the soil of Eastern Black Sea region of Turkey using the Monte Carlo simulation method. The results were given in nGy h−1 per Bq cm−2 as a function of depth. Simple numerical integration of this function multiplied with the known specific activity as a function of depth gives the absorbed dose conversion coefficients for any distribution of 137Cs in soil. Gaussian distribution of 137Cs in the soil was considered for calculations.