Determination of 131I in soil using a liquid anion exchanger and liquid scintillation technique

A simple method for rapid determination of 131I in soil is described. The method is based on the specific separation and concentration of radioiodine from the soil extract with a liquid anion exchanger and measuring its radioactivity using liquid scintillation counting techniques. The 131I from soil is extracted with aqueous solution of sodium hydroxide. 131I can be determined with lower limit of detection less than 0.1 Bq (2.5 pCi) per 10 g of soil measuring the radioactivity for about 60 min. The sample preparation for counting itself lasts about 3 hrs. Interference could be expected from the radioisotopes of Zr and Nb only. This interference can be easily suppressed by the addition of suitable carriers into the soil extract. The separation method can also be used to the determination of other fission radioisotopes of iodine. (T.G.)