河南郑州"7·20"特大暴雨灾害后核医学衰变池周围土壤中131I放射性水平调查及分析

Investigation of 131I radioactivity levels in soil around the nuclear medicine decay pool after the 7·20 extraordinary rainstorm disaster in Zhengzhou,Henan

目的探究"7·20"特大暴雨灾害后核医学衰变池是否存在放射性废水泄漏或溢出,分析其发生原因,为今后核医学衰变池的设计、建设、维护及核医学放射防护管理提供科学依据。方法选择郑州市3家开展131I治疗的医院(A、B、C医院),根据核医学衰变池周围环境辐射水平检测结果按标准方法设置采样点位,采集不同深度土壤样品。用高纯锗γ能谱仪测量土壤中131I的放射性水平,对检测结果进行处理和分析。结果除B医院未检出131I放射性核素外,A和C医院核医学衰变池周围土壤中均检出不同活度浓度的131I放射性核素,A医院131I的活度浓度范围为16.4~98111.8 Bq/kg,C医院131I的活度浓度范围为10.6~7176.6 Bq/kg。经过一段时间衰变后,对A医院和C医院进行复测,A医院131I的活度浓度范围为1.3~17.0 Bq/kg,C医院131I的活度浓度范围为3.9~7.1 Bq/kg。同一采样点位0~5 cm土壤中131I活度浓度均高于5~10 cm土壤中131I活度浓度,两者比值范围为1.3~13.1,比值中值为5.9。结论"7·20"特大暴雨灾害后,部分医院核医学衰变池周围环境发现不同程度的131I放射性污染。核医学衰变池在设计、评价、建设和使用时,应提高防范意识,做好放射防护安全评价和管理,防止放射性废水泄漏及溢出。

Objective To explore whether or not radioactive wastewater leakage or overflow exists in the nuclear medicine decay pool after the 7·20 extraordinary rainstorm disaster and to analyze its causes,so as to provide scientific basis for the design,construction and maintenance of the nuclear medicine decay pool and the radiation protection management of nuclear medicine in the future.Methods Three hospitals A,B and C where 131I therapy are being performed were selected in Zhengzhou city,Henan province.Sampling points were set based on the monitoring result of the environmental radiation level around the nuclear medical decay pool in line with the relevent standard method.Soil samples were collected at different depths.The 131I radioactivity level in the soil was measured using HPGe gamma spectrometer,with the measured result being processed and analyzed.Results Except for Hospital B where no 131I was detected,different 131I activity concentrations were detected in the soil samples collected around the nuclear medicine decay pool at Hospitals A and C.The 131I activity concentrations ranged from 16.4 to 98111.8 Bq/kg at Hospital A and from 10.6 to 7176.6 Bq/kg at Hospital C.After a time period of decay,the repeated detection has shown that the 131I activity concentrations ranged from 1.3 to 17.0 Bq/kg at Hospital A and from 3.9 to 7.1 Bq/kg at Hospital C.The 131I activity concentration in the soil at the depth of 0-5 cm was higher than that at the depth of 5-10 cm soil at the same sampling point.The ratios of activity concentration of 131I between different depths ranged from 1.3 to 13.1,with the median value of 5.9.Conclusions After the 7·20 extraordinary rainstorm disaster,the surrounding environment of nuclear medicine decay pools at a few hospitals was contamminated by 131I to some extent.To prevent the risk of leakage of radioactive wastewater,the safety evaluation and management of radiation protection should be made better with increased awareness during the design,evaluation,construction and use of nuclear medicine decay pools.