ne/kg, the corresponding values for the sedge, Carex equatilis, being 3.5 and 6.6. In 1961, 8.7 + 0.75 ne Foseg was reported as the average for 10 samples of sedges Z9/. For lichens the Alaskan values are somewhat lower, for sedges higher than the Finnish ones, but as a whole the picture is quite similar. Milk and tissues of reindeer and cattle have been analyzed both in Scan- dinavia and in Alaska since 1959. In summer 1960 cow’s milk in Lappland contained about 8 pc, reindeer milk 60 pe Ay per g Ca. During the winters 1960 and 1961 cow’s milk contained 15 pec Men/e Ca. Some values for meat and pone from Finland are presented in Table II. Beth annual and seasonal variations are apparent: This is due to the fact that on Lapp farms lichen is collected for winter and given to the cattle as “additional fodder" in such amounts that it makes up about 1/3 of the forage. Strontium is mainly (at least 99 per cent) located in the bones of the animals, which are not eaten by man, but radiocesium is located in meat, which is the main food of Lapps (reindeer meat) and several Eskimo tribes (caribou meat). Thus, this nuclide is the more important one from the viewpoint of man’s diet. ios content of reindeer meat is greatly decreased during the summer, when the animals mainly eat less radioactive vascular plants: zrass, sedges, horsetails and leaves of Vaccinium, willow and mountain birch. In summer (Ma, %o August) reindeer’s diet contains only about 5 to 10 % lienen. The Lowest re . 2 1 Flog. level is reached in July-August and since the biological half-time of los in reindeer is about 1 month Lis/s it is only about 1/8th of the winter level (Table II, 1963-samples). A similar decrease takes place in caribou meat in Alaska, where 3.6 nc/k fresh wt. was reported at Colville in May 1961, but 0.90 ne/kg in August 1961 Li4a/. The highest values from Alaska, 15 ne in Feb. “Ol and 26 ne in Dec. 61 /14// are of the same order as the contemporary values from Sweden L6/ and Finland (Table II), but from Norway max.37 ne (evidently winter value) is reported L1/> the level there being evidently about double that in Finland. In several studies different tissues of the same reindeer were analysed On. Tyan 7 for ? Sr / 4,10,16_/ or 1BT t Suan 7 Ca / 4,14_/. Liver, spleen and lung have about 1/3 : to 1/2, kidney 2/3 and blood 1/l0th of the 1 90 lL basis, The “observed ratio" ne ~“Sr/g Ca ontbssue liver 0.3, . . os content of meat, on fresh weight was for reindeer meat and lune and blcod 0.” and for reindeer milk in summer 6,2 L4/. With the knowledge of the high radioactivity of reindeer and high consumption of reindeer meat especially by the Lapps an accurate estimation of Poy and 137 Cs body burdens in Lapps evidently was of major interest. The quantitative . ; : sas . ae foe 7 ss O s investigation of the Lapps’ diet in 1960 / 3_//, and the 3 Se analyses of cow's a