Atmospheric dispersal of (129)iodine from nuclear fuel reprocessing facilities

(191)\/(171)\ ratios measured in meteoric water and epiphytes from the cont inental United States are higher than those measured in coastal seawater or surface freshwater and suggest long-range atmospheric transport of (129)\ from the main source for the earth's surface inventory, viz., nuclear fuel reprocessing facilities. The median ratio for 14 meteoric water samples is 2100 x 10(-12), corresponding to a (129)\ concentration of 2.5 x 10(7) atom s/L, whereas 9 epiphyte samples have a median ratio of 1800 x 10(-12) Calcu lated deposition rates of (129)\ in the continental United States reveal th at a small but significant fraction of the atmospheric releases from the nu clear fuel reprocessing facilities at Sellafield, England, and Cap de La Ha gue, France, is deposited after distribution by long-range transport. The i nferred dominant mode of transport is easterly, within the troposphere, mai nly in the form of the organic gas methyl iodide.