Determination of Atmospheric Concentrations of Stable Iodine

The importance of specific activity methods in the evaluation of radiological hazards due to the atmospheric release of 129I and 131I has prompted the development of analytical methods for determining atmospheric stable iodine concentrations. An analytical procedure based on neutron activation analysis for iodine trapped on filter paper and activated charcoal was developed. This procedure was used to measure the airborne stable iodine concentrations in several areas around Atlanta, Georgia and Barnwell, South Carolina. Airborne stable iodine concentrations determined in this study are in the range 10-9 - 10-8grams/m3. These concentrations are consistent with others reported in the United States but fall below those reported in the United Kingdom by a factor of 100. The collection and retention of iodine on charcoal appears to depend on the following factors: air flow rate, chemical form, presence of oxides of nitrogen, and relative humidity. The influence of these factors on iodine collection and retention on charcoal are in need of further study as related to airborne iodine measurements.