Environmental contamination with radioruthenium, 1961-1965.

Abstract

The results of measurements of medium-lived 103Ru and 106Ru in air-borne particles, fall-out, surface soil, river water, sea-water, foodstuffs, complete diet and human muscle and lungs during 1961-1965 are summarized. Main passage route of 103Ru was found through the fresh leafy vegetables, while 106Ru was supplied by different way, i. e., 77% by plant materials raised on land, 6% by foodstuffs of animal origin and the remainder by seaweed ; the concentration was the highest in the last item. Estimation of lung and body burdens was performed on the basis of observed data for inhalation and ingestion and compared with the result of measurements on human materials obtained from cadavers. The mobility of fall-out ruthenium in the sequence between precipitation and run-off from rivers seemed a little larger than strontium and much larger than cesium, reaching 14% of fresh fall-out to be delivered to the sea. Average concentration factor from sea-water to sea food as a whole was found to be 70 or equivalent daily intake of sea-water to be 7 kg. On this basis, the maximum permissible concentration of 106Ru in sea-water was suggested as 3 × 10-6μCi/ml.