Measurement And Evaluation Of Drinking Water And Environmental Radioactivity Level In Huhhot City

Objective?1?To investigate radioactivity level of factory water from all water plants in Huhhot City and to estimate the annual effective dose of residents' internal exposure caused by intake of radionuclide from drinking.?2?To determine activity concentration of natural and artificial radionuclides in the surface soil of Huhhot City,to measure environmental radioactivity level,and to evaluate risks posed to residents' health.Method A method of combining cross-sectional surveys with experiments is employed.?1?Take samples from all nine water plants of Huhhot City and measure radioactivity of gross ? and ? using a low-background ??? radioactivity measuring instrument;measure activity concentration of ²²⁶Ra and ⁴⁰K using a high purity germanium ? spectrometer;analyze contents of U with inductively coupled plasma mass spectrometry;detect concentration of water radon by RTM2200.?2?determine radionuclide in 48 surface soil samples by means of the high purity germanium ? spectrometer;measure environmental activity level using an environment ? dose rate meter;compare average radioactivity level between domestic soil and soil around the world and estimate the exposure dose for residents by virtual of a method recommended by UNSCEAR and related literature,and calculate the lifetime cancer risk for residents.Result?1?In factory water of Huhhot City,the activity concentration of gross ? ranges from0.016⁰.491 Bq/L and that of gross ? is 0.046⁰.519 Bq/L;the activity concentration of ²²⁶Ra and ⁴⁰K are 0.002⁰.027 Bq/L and 0.010⁰.210 Bq/L respectively;the content range of U is 2.2⁴.7 ug/L and that of water radon is 0.13⁶.20 Bq/L;the annual effective dose of residents' internal exposure caused by intake of gross ? from drinking is 0.034-0.063 mSv per year.?2?The average values for activity concentration of ²³⁸U,²³²Th,²²⁶Ra,⁴⁰K and 137 Cs in the surface soil samples of Huhhot City are 29.29±12.95,39.33±4.34,29.77±3.21,650.49±62.21 and 1.62±1.53 Bq/kg respectively;the measured air absorption dose rate is 86.32±11.92 nSv/h;the annual effective dose of local residents caused by outdoor and indoor ? radiation is 672.11 ?Sv/a and the lifetime cancer risk is 2.52×10^-3.Conclusion?1?Gross ? and ? in factory water of Huhhot City have an activity concentration value lower than National Standards;the activity concentration of ²²⁶Ra and ⁴⁰K is below the standards of World Health Organization?WHO?;and the content of U is also below the threshold stipulated by WHO;the annual effective dose of residents caused by drinking is under safety level.?2?The natural radioactivity concentration and environmental radiation in surface soil of Huhhot city are at a normal low-background level,which poses low risks to residents' health.