Gamma Dose Rate Measurement and Dose Rate Calculation for Sensitive Organs in the Vicinity of Hot Springs in Kerman Province

Introduction:  All of  the  people worldwide  are exposed  to  low levels  of  radiation. Cancer induction  and  genetic disorders are among the hazards of low level exposure. In some cases, radiation close to hot springs is  higher than normal areas due to a high concentration and the decay products of Ra-226. Given the use of hot  springs by the general public  because  of their therapeutic properties, preparation  of a guideline based on  radiation levels of hot springs is believed to be necessary. In this study, gamma dose rate in the vicinity of hot  springs in Kerman province was measured and the dose rates for sensitive organs were calculated.  Materials and Methods: The equipments used in this study were an RDS-110 survey meter, a tripod with an  aluminum frame, a chronometer and a thermometer. After defining 19 stations (one near each hot spring), the  survey meter was fixed horizontally one meter above the hot spring and the gamma dose rate was recorded  during  one  hour.  Then,  using  the  corresponding  coefficients,  equivalent,  effective,  bone  marrow  and  reproductive  organs  dose  rates  were  calculated.  Independent  T  test  and  variance  analysis  were  used  for  comparison of the means.  Results: Gamma absorbed dose rates  near nineteen hot springs in  Kerman province were measured.  The  results showed that Amirekeykhosravi Spring had the highest annual dose rate (1.65  ± 0.54  1 mSvy ) and  Gharayoob Spring had the lowest annual dose rate (0.53  ± 0.23  1 mSvy ). Also, the annual bone marrow  and reproductive organs dose rates were within the ranges 0.42  ± 0.18  1 mSvy  to 1.32  ± 0.43  1 mSvy   and 0.43  ± 0.19  1 mSvy  to 1.34  ± 0.44  1 mSvy , respectively.   Discussion and Conclusion: This study shows that the maximum annual dose rate in the vicinity of the hot  springs in Kerman province was 120% higher than the outdoors annual dose rate for normal areas. This is  due to the existence of radioactive elements in spring water and the high altitude of the springs from the sea  level.  Due to the high dose rate to sensitive organs, it is suggested that Chegeri,  Ghaneghah, Gharayoob,  Joshan  and  Chaharfarsakh  springs  are  used  as  spas.  Also,  according to  the  results, there  is no  correlation  between the gamma dose rate and the temperature of the springs.