«-antesapere SIRIIEnOmee emn l | 130 a 20Pl AND 29Po IN TISSUES OF SOME ALASKAN RESIDENTS The order of listing is the same as that used in in the #°Po concentration with consumption of ‘The concentrations are based upon fresh weight for the soft tissue and defat weight for the rib samples. ‘The uncertainties shownare for a one and, as he dicd on December 19, had included caribott meat in his diet for 3-4 monthspriorto Table 1; lower to higher caribou consumption. standard deviation counting error. ‘The values observed in the samples from the Alaskan subjects, #1 and #2, who had caten no caribou meat are within the nermal range of valuesreportedfor unexposed populations, (8292) Vhe lower lung and rib levels reported for #1 are probably due to her young age, 6 yr. Hence, if these two sets of tissues may be assumed typical, then the "Ph !’Po body broaden of an Alaskan whose dict does not inefude caribou or remdeer meat is similar to Giat of individuals residing in the conterminous United States. The 7Pb and 7!’Po tissue concentrations of subject #3, who ate caribou meat while m Barrow but none during the last 3 yr while living in Anchorage, are somewhat less but not significantly different from those of unexposed USS. residents.@! 2) As Ilitn has reported high 40Pl) levels in 3 human bone samples from northern Canada," and considering the 2400day half-life of “°Pb in the skeleton,“ it was somewhat surprising, if the dietary information Is correct, that the bone ievel im this case Is not higher than that observed. Subjects #+ and #5, who occasionally included caribou meat in their diet, contained significantly higher concentrations of 7!°Po in the kidney and liver samples and possibly in the testes of the fatter. The concentration of Phin the rib sample of #5 is high with respect to the other rib samples caribou or reindeer meat. Subject #7 ate caribou regularly in winter, death, Subject #6 included caribou meat in her dict a few times each month, while #8 ate reindcer regularly until 3 months prior to his death, during which time he had eaten none. It is quite interesting that although these three subjects had clevated #!°Po soft tissue levels, their 2"Pb bone concentrations do not show a proportional increase, and fall within the range reported by HorrzMaAn for concentrations observed in human bone samples ofresidents of the conterminous United States.2” It has been reported that although caribou bones, liver and kidney contain high concentrations of *!¢Pb,“ the concentration in the meatis low, 5-16 pCi/ kg,'® and not much different from that observed for beef in the conterminous United States. Consequently, unless the subject had consumed an extract of the cartbou bone or a soft tissue which concentrates #1°Pb, as liver or kidney, the *0Pb skeletal burden would probably not be expected to be muchhigher than for individuals who consumed no caribou meat. The *!°Po/*!Pb activity ratio exceeds one and is generally much greater in soft tissues of the subjects who ate caribou or reimdeer meat. Sunilar results were recently reported by KaurRAneN and Muirrtinen for reindeer breeders living in Lapland.@ These high activity ratios measured: however, it cloes fall within the concentration range reported by HourzMan for are especially significant in the case of the lung for which activity ratios of less than one are usually observed.@” Since the ground-level air concentration of 7!°Pb is about 10 times greater than #!0Po,'° these results suggest exposure by a route other than inhalation and by a source containing Po in excess of 7Pb,. These observations support the conclusion that caribou #i/7 and 48 were about 4, 14 and 18 times, for this population. Whenlarge quantities of 2!°Pb are ingested,it is concentrated in the skeleton with an effective an unexposed population.@” The results showed significantly higherlevels of 720Po in the soft tissues of subjects considered to be caribou or reindecr meat eaters. Vhe concentration of Po in tissucs of subjects #6, respectively, the values reported for tissues of an unexposed population.'87920) Smoking data or reindeer meatis the principal source of 21°Po half-life of about 2400 days.@) During this time, the *#°Po grows into near radioactive their 7*Po lung concentrations are significantly equilibrium with the ?!9Pb and serves as a higher than observed even in the lung of reservoir for other body compartments.'? cigarette smokers." "The results in ‘Table 2 ‘That is, sorePo is translocated from the also show, except for bone, a general increase skeleton to other body tissues which sustains the are not available for these Alaskans; however,