Speciation analysis for 129I and 127I in air and its tracer application in geochemcial cycle of stable iodine

A method for the collection and separation of different species of iodine in air was developed. Particle associa.ted iodine, inorganic gaseous iodine and organic gaseous iodine were collected by pumping the air through air sampler with sequential air filters, a glass fibre filter, cellulous filter impregnated in NaOH/glycerol and a active charcoal column impregnated with TEDA.

The collected different species of iodine were then separated by a combustion method and trapped in an alkali solution. 127I in the trap solution is measured by ICP-MS. Iodine remained solution was further separated by solvent extraction and AgI precipitation for AMS measurement of 129I. Total 45 air samples at 8 locations with different distance to the North Sea (0, 5, 50, 100, 250, 500, 1000 km) in Denmark, Sweden, and Lithuania have been collected in March and September 2007, meanwhile lichen, pine needle, surface water, and rain water samples have also been collected near the air sampling sites.

Iodine in 25 lichen and pine needle samples has been separated using the combustion furnace. The results show a high 129I/129I ratio in air sample as well as lichen samples in the short distance to the North Sea, especially those collected in a 10 km distance to the North Sea. The lowest value was observed in the Lithuania, where is 1000 km far from the North Sea.

The application of anthropogenic 129I released from reprocessing plant for geochemical cycle is discussed in this work.