Quantitative Measurement of Gamma Activities of Radionuclides (<sup>131</sup>I, <sup>137</sup>Cs, <sup>134</sup>Cs and <sup>40</sup>K) in Human Urine Samples Collected from Residents in Southern Region of Thailand

Highpurity germanium (HPGe) detector and gamma spectrometry analysis system have been used for the determination of gamma activities of radionuclides (131I, 137Cs, 134Cs and 40K) in 90 human urine samples collected from residents in four provinces (Surat Thani, Nakhon Si Thammarat, Songkhla and Trang) in southern region, Thailand. Gamma radioactive standard sources (109Cd, 57Co, 133Ba, 137Cs, 54Mn and 60Co) were used to calibrate the detector and measurement system. Moreover, the well-known reference material 131I in human urine were also used to analyze and determine all of human urine samples. The measuring time of each sample is 10,800 seconds. It was found that, the gamma activities of 131I, 137Cs, 134Cs and 40K in all samples were ranged from 0.35 7.74 Bq/d for 131I, 0.28 7.38 Bq/d for 137Cs, 0.20 9.93 Bq/d for 134Cs and 8.56 274.32 Bq/d for 40K with an average values of 2.40 ± 0.78 Bq/d, 2.41 ± 0.92 Bq/d, 2.66 ± 0.84 Bq/d and 93.50 ± 30.13 Bq/d, respectively. All results showed that no statistically significant correlation with the residential area. Furthermore, the present study data could be used to be a baseline data of gamma activities in human urine of Thai people in the southern Thailand. Moreover, this new database would be not only useful in comparing and assessing an amount of gamma activities inside human body but also monitoring the exposure of radioactivity to Thai people in case of emergency of nuclear accidents around the world.