Fallout Strontium-90 and Cesium-137 in Northern Alaskan Ecosystems During 1959--1970

• Main Author: Hanson, W.C.
• Format: Thesis
• Language: English
• Published: Colorado State University. Department of Radiology and Radiation Biology 1973
• Subjects: *Eskimos > Radiation Doses; Diet; Radiation Monitoring; Whole-Body Counting; Man; Fallout; Arctic Regions; N44340* > Environmental & Earth Sciences > Radioactivity Monitoring & Transport > Ecosystems & Food Cycles; *Alaska > Fallout Deposits; Radionuclide Migration; Age Dependence; *Strontium 90 > Radioecological Concentration; Human Populations; N48700 > Life Sciences > Nuclide Kinetics & Toxicology; Lichens; *Cesium 137 > Radioecological Concentration; Terrestrial Ecosystems; Biological Half-Life; Deer; Natural Radioactivity; Meat; Food Chains; Radionuclide Kinetics; Arctic; Indian; eskimo*; Alaska
• Online Access: https://doi.org/10.2172/4425152; https://digital.library.unt.edu/ark:/67531/metadc1022479/

Thesis. Cycling routes, rates of transport, and resultant concentrations of the fallout radionuclides /sup 90/Sr and /sup 137/Cs in northern Alaskan ecosystems were defined during the period 1959 to 1970. Radiochemical analysis of extensive samples of biota and whole-body counting of / sup 137/Cs in Eskimo and Indian ethnic groups were related to ecological principles, especially the concept of trophic niche, which elucidated the observed patterns of radionuclide concentrations. Experiments involving Sr and Cs radioisotopes applied to natural Cladonia-- Cetraria lichen carpets yielded effective half-times of 1.O to 1.6 years for Sr and more than 10 years for Cs. Direct and indirect estimates of /sup 131/Cs half-times in Eskimos on a caribou meat diet were made by dietary manipulation and by relating dietary /sup 137/Cs intake and resultant change between periodic whole body counts. Effective half- times of 70 days for adults (more than 21 years old) and minors (14 to 20 years old) and of 45 days for children (less than 14 years old) were found. Suitable mathematical models were used to compute lichen forage ingestion rates of free- ranging adult caribou (4.5 to 5.0 kg dry weight per day), caribou meat ingestion rates of Anaktuvuk Pass residents (up to 2 kg wet weight per day for men), and / sup 90/Sr body burdens of Anaktuvuk Pass residents during the period 1952 to 1968 (maximum value of 8 nCi in adult males during late 1966 to early 1967). Special emphasis was made of cultural influences upon the food-gathering patterns of the native peoples studied. Culture change, especially in the form of food stamps, welfare payments, acquisition of snowmobiles, and improved housing was documented throughout the study and noticeably reduced the radionuclide accumulations. Total radiation dose rates to the Anaktuvuk Pass adult population were estimated to be about 100 mrad/year from natural sources, 60 to 140 mrad/year from /sup 137/ Cs body burdens, and 20 to 130 mrad/year from /sup 90/Sr body burdens. (CH)