核电站正常运行期间毗邻地区出生缺陷的流行病学分析

Epidemiological Analysis of Birth Defects in the Adjoining Areas of a Normal nuclear Power Station

目的了解、探讨秦山核电站Ⅰ期30万kW机组(以下简称秦山Ⅰ期机组)正常运行10余年来(1992～2003年),其向周围环境排放的放射性流出物可能引起的海宁市环境放射性介质浓度与出生缺陷发生率的变化。方法收集秦山Ⅰ期机组运行前和正常运行以来的海宁市环境放射性介质浓度监测资料、出生缺陷资料。以街道、镇行政区域为单位,根据距秦山电站厂址不同等公里半径进行分组,运用分析流行病学方法,分析各组间和秦山Ⅰ期机组运行前后的环境放射性介质浓度和出生缺陷发生率的变化数据。结果海宁市室外环境平均γ辐射强度在秦山Ⅰ期机组运行前后分别是:(6.17±0.56)×10-8Gy/h(1991年)和(7.92±0.77)×10-8Gy/h(2002年);2002年检测水质中放射性核素90锶和137铯的平均浓度分别为4.41mBq/L和1.26mBq/L;1993～2003年10年间海宁市年平均出生缺陷儿发生率为9.24‰。结论海宁市γ辐射空气吸收剂量率数据显示均在天然辐射本底水平涨落范围之内,海宁市γ辐射吸收剂量率水平属正常地区;对照秦山Ⅰ期机组运行前后海宁市及周边县市淡水中放射性核素90锶和137铯的平均浓度未见明显增高;对比秦山Ⅰ期机组运行前后出生缺陷儿年平均发生率的相关资料,出生缺陷儿年平均发生率也未见明显上升;分析距秦山核电站不同等公里半径人群分组的出生缺陷儿发生率无显著差异。

Objective The research was designed to investigate the environmental radioactive concentration and the changes in the incidence of birth defects in Haining city of where Qingshan phase Ⅰ nuclear power station of 300,000 kW unit （hereafter referred to as Qingshan phase Ⅰ unit） had been in normal operation for more than 10 years （from 1992 to 2003）. Methods Data on the environmental radioactive concentration and birth defects before and since normal operation of Qingshan phase Ⅰ unit in the city of Haining were collected. Streets and the administrative regions were taken as investigated units and they were grouped based on different radius distance from the site of Qingshan nuclear power station at equal kilometers. Data on the enviroranental radioactive concentration and birth defects before and since normal operation of Qingshan phase Ⅰ unit in the city of Haining were analyzed using analytical epidemiological methods. Results Data analysis showed that the mean radiant intensity in the outdoor environment in the city of Haining before and after Qingshan phase I unit operation were（6.17±0.56）×10^-8Gy/h（in 1991）and （7.92±0.77）×10^-8Gy/h （ in 2002）, respectively. Water quality detection in 2002 revealed that mean concentrations of radionuclide strontium-90 and cesium-137 were 4.4,1 mBq/L and 1.26 mBq/L respectively. The 10-year mean incidence of birth defects from 1993 to 2003 in the city of Haining was 9.24%. Conclusion The air absorbed gamma-radiation dose rate in the city of Haining is with the fluctuation range of natural radiation background. Compared with the mean concentration of radionuclide strontium-90 and cesium-137 before Qingshan phase I unit operation, there is no significant increase in the mean concentration of the 2 kinds of radionuclide. There is no significant increase in the mean annual incidence of birth defects after Qingshan phase I unit operation. Analysis of the subjects grouped based on different radius from the site of Qingshan nuclear power station at equal kilometers finds no significant difference in the incidence of birth defects between groups at different distances from the station.