Vol.:(0123456789) 1 3 Journal of Radioanalytical and Nuclear Chemistry https://doi.org/10.1007/s10967-019-06688-2 Investigation of radon concentrations of underground metro and Marmaray stations in Istanbul H. Yilmaz Alan 1  · B. Akkus 2  · L. Amon Susam 2 Received: 28 March 2019 © Akadémiai Kiadó, Budapest, Hungary 2019 Abstract In this study, radon (Rn) measurements were evaluated for the frst time in the underground metro and Marmaray stations in Istanbul and the annual efective dose values were calculated to the employees and for passengers. Radon concentrations ranged from 39.47 to 382.02 Bq m −3 for the railway platforms. The average radon value for all station platforms found to be 114.60 Bq m −3 . The annual efective dose values for the employees working at the platforms varied from 0.12 and 2.75 mSv y −1 , while the data for the passengers were varied from 0.035 and 0.34 mSv y −1 . Keywords Radon concentrations · Efective dose · Underground metro Introduction Radon is a colorless, odorless, tasteless and a radioactive gas that is the product of radioactive decay chain of ura- nium, has a half-life of 3.82 days. Radon declared as a car- cinogenic substance by international organizations and it is impossible to be sensed by people [1]. Studies are carried out to determine the amount of radon in homes, tunnels, caves, subway stations and underground working areas [2]. Radon exists everywhere because it is an inert gas which is a naturally occurring radionuclide and is one of the most important contributors to human exposure from natural radiation sources. Generally, radon has highest levels in the basements and at the underground levels of the buildings that are close to soil, such as underground shopping malls, underground stations, mines and caves. Radon and the prod- ucts from the degradation of uranium and radium produced continuously and spread throughout the atmosphere from the rock layers on solid earth [3]. A part of radon taken into the lungs can be exhaled by respiration, stick to the airborne dust particles and continue to decompose into the lungs by breathing. Radiation that occurs in this process can alter the DNA structure of cells and cause lung cancer [4]. Radon gas is one of the leading causes of lung cancer after smoking. The concentration limits of radon in Turkey determined as 400 Bq m −3 for houses and 1000 Bq m −3 at the workplaces by Turkish Atomic Energy Authority (TAEA) [5]. Due to the International Commission on Radiological Protection (ICRP) the lowest radon concentration limits for dwellings is 300 Bq m −3 and the highest limit is 1000 Bq m −3 [6]. Moreover, it has been shown that there is a direct rela- tionship between the underground radon gas emission and seismic activities [7]. Radon gas leakage is known to be higher on active faults and it is also known that radon leak changes due to atmospheric conditions and seismic activi- ties. The increase in the amount of radon gas reaches a maxi- mum value before the earthquake and returns to its natural state after the earthquake. With the aftershocks during and after the earthquake, radon is released. For this reason, it is necessary to measure the amount of radon especially on the fault line and in places with high risk of depressions [8]. In the literature there are special works on measuring radon concentrations of underground metro stations. Due to these references the indoor radon concentrations in the subway were highly dependent on the management approach of a ventilation system at the stations. In this study, because the radon levels are typically higher in old buildings, in the underground structures and all over the areas in contact with soil, by the inspiration from these works we determined the radon levels in ofces, ticket gates, platforms and tram drivers’ room at the underground stations * H. Yilmaz Alan hyalan@ankara.edu.tr 1 Institute of Accelerator Technologies, Ankara University, Ankara, Turkey 2 Science Faculty, Istanbul University, Istanbul, Turkey