This paper reviews historical concentrations of radiocesium (Cs-137) in the reindeer/caribou food chain in Alaska. These data, along with available kinetic models which describe the movement of radiocesium through the food chain, are used to predict consequences of radioactive fallout from the Chernobyl accident which occurred in late April 1986. During the present discussion, efforts are made to directly relate the Alaskan data to the Scandinavian situation as it exists following the Chernobyl accident.

The Porcupine caribou herd was monitored for cesium-137 during 1987 to address human health concerns over potential meat contamination by radioactive fallout from the Chernobyl accident, and to determine lichen intake rates based on body burdens of radiocesium. A total of 36 caribou were collected from northwestern Alaska and the Yukon Territories in March, June, September, and November. Mean radiocesium concentrations in skeletal muscle peaked in March at 133 Bq/kg fresh weight. This value should not prove hazardous to human health. Radiocesium concentrations in skeletal muscle (wet weight) ranged from approximately 22 to 50% of radiocesium concentrations in rumen contents (dry weight), and from approximately 15 to 37% of radiocesium concentrations in feces (dry weight). Radioactivity in feces was significantly correlated with radioactivity in rumen contents. Computer simulations relating lichen intake rates to radiocesium body burdens are presented for 3 scenarios: (1) when seasonal intakes were adjusted to provide the optimum fit between simulated and observed radiocesium body burdens (2) when seasonal intakes were based on empirical data, and (3) when seasonal intakes were adjusted to yield a "conventional" radiocesium curve of a slow fall build-up prior to a late winter plateau

The environmental contaminate radiocesium (cesium-137) has been shown to be of value as a marker in food selection and intake studies. Its greatest potential value as a food marker is in the subarctic/arctic regions, particularly in the lichen to reindeer/caribou to wolf food chain. A kinetic model describing the movement of radiocesium through the food chain has been developed using the SAAM computer program and is presented here. The program has been written so that the various paramenters affecting the transfer of radiocesium in the food chain can be altered more realistically to describe the system being modeled. The values of the parameters as given in this example are realistic for interior Alaska, however caution should be exercised in the application of the present results to regions that may be vastly different from the Alaskan interior without first evaluating the parameters and assumptions of the model

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