The XeBr excilamp (B-X transition, l = 283 nm) was shown to decompose urine and organoiodine. In addition to decomposition of organic matter, the excilamp based on KrCl* molecules (B-X transition, l = 222 nm) deactivates the dissolved oxygen and converts IO3- to I-. The contents of I- in a prepared sample was determined by the cathodic stripping voltammetry technique with formic acid admixtures.