| Summary: | Tundra sampling was accomplished in 1989--1990 at Imnavait Creek, Alaska (68{degree}37` N, 149{degree}17` W). Inventories of {sup 137}Cs (102--162 mBq/cm{sup 2}) are close to expectations, based upon measured atmospheric deposition for this latitude. Accumulated inventories of {sup 137}Cs in tundra decrease by up to 50% along a transect to Prudhoe Bay (70{degree}13` N, 148{degree}30` W). Atmospheric deposition of {sup 137}Cs decreased with latitude in the Arctic, but declines in deposition would have been relatively small over this distance (200 km). This suggests a recent loss of {sup 137}Cs and possibly associated organic matter from tundra over the northern portions of the transect between Imnavait Creek and Prudhoe Bay. Sediments from Toolik Lake (68{degree}38` N, 149{degree}38` W) showed widely varying {sup 137}Cs inventories, from a low of 22 mBq/cm{sup 2} away from the lake inlet, to a high between 140 to >200 mBq/cm{sup 2} near the main stream inflow. This was indicative of recent accumulation of cesium and possibly organic material associated with it in arctic lakes, although additional sampling is needed.
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