THE VARIATION OF IODATE AND TOTAL IODINE IN SOME UK RAINWATERS DURING1980-1981

A complete sequence of daily rainfall (bulk precipitation) samples col lected between January 1980 and April 1981 at Wallingford, in central Southern England, together with a few month's samples from other sites in west Wales, northern England and southern Scotland, have been anal ysed for iodate and total iodine concentration. The wet deposition of iodine depended mainly upon the amount of rainfall, and the average mo nthly total iodine concentration was not found to vary seasonally as h ad been anticipated. This behaviour contrasted markedly with that of c hloride and sodium ions, whose average monthly concentration decreased during summertime. On average, iodate composed one-half of the total iodine. The iodine chemistry of the rainfall is discussed in terms of the equilibrium between HOI and I-2, and between iodine and other redo x systems, e.g. peroxide and ozone.