REETTe reeceeeeee nec nenaee 407966 Health Physics Pergamon Press 1970. Vol. 18, pp. 127-134. Printed in Northern Ireland 21°Ph AND *°Po IN TISSUES OF SOME ALASKAN RESIDENTS AS RELATED TO CONSUMPTION OF CARIBOU OR REINDEER MEAT ft R. L. BLANCIIARD and J. B. MOORE* U.S. Department of Health, Education and Welfare, Public Health Service, Environmental Control Adininistration, Bureau of Radiological Health, Cincinnati, Ohio 45202, U.S.A. (Received 17 February 1969; in revisedform 5 May 1969) Abstract—Concentrations of *!°Pb and 2!9Po in tissues of Alaskans who eat caribou meat are compared with the concentrations in tissues of individuals whose diets do not include this meat. The fevels of 2!°Po were significantly higher in those individuals who had caten caribou meat a short time before death; however, only small differences were observed in the #!°Pb levels between the two groups. The concentrations of 249Pb and #!°Po in lichen and in caribou bonesamples which were collected prior to the advent ofnucleartesting in the arctic were not found todifier significanthy from the concentrations in similar samples recently collected. These results indicate that nuclear fallout has not significantly increased the #°Pb levels in the arctic environment. INTRODUCTION ELEVATED levels of the fission products Sr and 137C's exist in certain Alaskan populations that include caribou meat as a portion of their diet."-5) These radionuclides enter the arctic ecosystem as fallout from nuclear detonations and are accumulated by lichens which are consuined in large quantities by caribou and reindeer.’) In addition to Sr and #7Cs, 210Pb and #!°Po have also been observed to be in high concentrations in lichens and in bones and some soft tissues of caribou, while in the muscle of the latter, high levels of *4°Po have been observed.{@-® For this reason, it has been suggested that populations who consume a regular diet of caribou or reindeer meat mayalso have high body burdens of #°Pb and *°Po, The latter, being an alpha emitter, is particularly hazardous in high concentrations with respect to internal radiation exposure, 9 The body burdenof ’Cs has been measured extensively throughout the caribou eating populations of Alaksa by whole-body counting techniques employing gamma-spectrometry. S52) The measurement of the body burden of #4°Pb and *°Po in this population, however, is considerably more dilficult. Measurements must be conducted on autopsy tissue by radiochernical techniques. ‘The diilicult task of obtaining appropriate specimens is reflected in the scarcity of reported measurements. HILi has reported the 7!Po concentrations in 18 samples of human placenta,“ and the 2!’Pb content of 3 bone samples from northern Canada. [In addition, Ho-rzman has reporied concentrations of 48Pb and 7!Po in 3 placenta and | blood sample from subjects residing near Barrow, Alaska.” As a result of the absence of“Po and #!°Pb measurements im tissues from the Alaskan Eskimo, it has been possible only to compute an approximate body burdenof these nuclides from either the analyses of caribou meat with an estimated intake or from urine analyses. From the latter, BEASLEY and PaLMrrhave estimated that the average *4°Po body burden ofpeople living at «Anaktuvuk Pass, Alaska is 3.5 n€i. It has been generally accepted that the source of the ?!°Pb in the arctic ecosystem, as in other regions, * Address: Radiological Engineering Laboratory, 5555 Ridge Ave., Cincinnati, Ohio 45213. is from the decay of atmospheric 222 n.'8-9) Lead atoms so formed return to the 12? BEST COPY AVAILABLE