Adelikhah Mohammademad, Shahrokhi Amin, Chalupnik Stanislaw, Tóth-Bodrogi Edit, Kovács Tibor
Institute of Radiochemistry and Radioecology, University of Pannonia, Egyetem u. 10, Veszprém, Hungary.
Silesian Centre for Environmental Radioactivity, Central Mining Institute, Plac Gwarków, 40-166, Katowice, Poland.
Heliyon. 2020 Jul 1;6(7):e04297. doi: 10.1016/j.heliyon.2020.e04297. eCollection 2020 Jul.
It has been proven that more than half of the exposure to natural background radiation originates from radon isotopes and their decay products. The inhalation of radon and its decay products causes the irradiation of respiratory tracts, thus increasing the risk of lung cancer. In this study, the concentrations of radon and thoron in thermal baths at a spa in Dehloran (Iran) were investigated. The concentrations of dissolved Ra in samples of water from thermal baths were also measured. Additionally, the activity concentrations of abundant naturally occurring radionuclides in farmland soils irrigated with water from hot springs was measured and compared with other soil samples irrigated with water from other sources to estimate possible radioecological effects of natural radiation staff, patients and tourists at the spa are exposed to. In addition, the search for a link between the concentration of naturally occurring radionuclides in soil and the use of water from hot springs for irrigation was one of the main goals of the study. The activity concentrations of three major naturally occurring radionuclides in soil samples were measured; the ranges for K, Ra and Ra were 101 ± 8 to 240 ± 12, 276 ± 7 to 322 ± 12 and 20 ± 7 to 80 ± 10 Bq.kg, respectively. Higher activity concentrations of Ra and Ra were recorded in soil samples irrigated with hot spring water. The water from the same spring was used in all thermal baths so concentrations of dissolved Ra in water samples from different thermal baths were approximated to also be 0.42 ± 0.20 Bq.l. The indoor radon concentrations in the private thermal baths over a period of 45 days (including both occupied and vacant time) were measured to be between 1880 ± 410 and 2450 ± 530 Bq.m and the radon concentrations in the spa galleries were measured to be between 790 ± 135 and 1050 ± 120 Bq.m, however, thoron concentrations were below the detection limit. The ventilation and centralized heating systems at the spa under investigation are inefficient so the radon concentrations in the therapy rooms and baths are high. The maximum radiation doses originating from the inhalation of radon for tourists and the staff were estimated to be 0.13 and 5.5 mSv.yr, respectively, which is slightly over the national limit in Iran (5 mSv.yr). The exposure duration was estimated 15 and 1468 h per year for visitors and workers, respectively.
已经证实，超过一半的天然本底辐射暴露源自氡同位素及其衰变产物。吸入氡及其衰变产物会导致呼吸道受到照射，从而增加患肺癌的风险。在本研究中，对伊朗德洛兰一个温泉浴场中氡和钍射气的浓度进行了调查。还测量了温泉浴场水样中溶解镭的浓度。此外，测量了用温泉水灌溉的农田土壤中大量天然存在的放射性核素的活度浓度，并与用其他水源灌溉的其他土壤样本进行比较，以评估温泉浴场工作人员、患者和游客可能受到的天然辐射的放射性生态效应。此外，寻找土壤中天然存在的放射性核素浓度与使用温泉水进行灌溉之间的联系是该研究的主要目标之一。测量了土壤样本中三种主要天然存在的放射性核素的活度浓度；钾、镭 - 226和镭 - 228的范围分别为101±8至240±12、276±7至322±12和20±7至80±10 Bq.kg。在用温泉水灌溉的土壤样本中记录到了较高的镭 - 226和镭 - 228活度浓度。所有温泉浴场都使用同一泉水，因此不同温泉浴场水样中溶解镭的浓度估计也约为0.42±0.20 Bq.l。在45天的时间段内（包括有人使用和无人使用的时间），测量了私人温泉浴场中的室内氡浓度在1880±410至2450±530 Bq.m之间，温泉走廊中的氡浓度在790±135至1050±120 Bq.m之间，然而，钍射气浓度低于检测限。所调查的温泉浴场的通风和集中供暖系统效率低下，因此治疗室和浴场中的氡浓度很高。游客和工作人员因吸入氡而产生的最大辐射剂量估计分别为0.13和5.5 mSv.yr，略高于伊朗的国家限值（5 mSv.yr）。估计游客和工作人员每年的暴露时长分别为15小时和1468小时。
