WET AND DRY DEPOSITION OF I-131, CS-134 AND CS-137 AT AN UPLAND SITE IN NORTHERN ENGLAND

Samples of cloud and rain water, soil and vegetation were collected from sites at up to 847 m altitude on Great Dun Fell in northern England during the period 2-6 May 1986. Wet deposition is the dominant depositional process for Ru-103 and the caesium isotopes, whilst dry deposition is much more important for I-131 The observed deposition velocity for I-131 is 3.4 mm s-1. The patchy distribution of activity is related to the convective nature of the rainfall, and there is evidence of direct deposition of contaminated orographic cloud water at the highest site.