Factors influencing the accumulation of fallout cesium-137 in mule deer

Whicker, F. Ward, author
Dahl, Adrian H., advisor
Remmenga, Elmer E., committee member
Thompson, Robert D., committee member
Steinhoff, Harold W., committee member
Journal Title
Journal ISSN
Volume Title
Colorado State University. Libraries
This investigation was concerned with factors influencing the accumulation of fallout cesium-137 in a wild population of mule deer, Odocoileus hemionus, in the Cache la Poudre drainage of north-central Colorado. Air, precipitation, soils, twelve deer forage species, and deer were sampled periodically from various elevations within the study area over a three year period. Experimental sampling designs were primarily factorial with sufficient replication to allow statistical treatment of data. Materials were assayed for Cs-137 using the technique of gamma-ray spectrometry. Air concentrations of Cs-137 were maximal in 1963. Concentrations were significantly higher during spring and early summer months of each year. Maximum deposition of Cs-137 by precipitation in 1964 occurred during April, May, and June. Measurable quantities of fallout were transported by dust, pollens, and other air-borne debris during dry, windy periods. The majority of Cs-137 in soils was located in the 0-1 inch layer. Soil radio activity generally increased with elevation and associated higher average precipitation rates. Maximum vegetational levels of Cs-137 were observed in 1963. Species collected during the summer and fall above 8,500 feet were generally higher in cesium than species collected during the winter and spring from lower elevations. Significant differences between species growing on the same plots were found. Significant differences in Cs-137 concentrations of given species between locations were also encountered. The location effect was attributed mostly to phenomena associated with elevation. Leaves were generally higher in Cs-137 than stems. Maximum levels of Cs-137 in deer were observed in 1963. Maximum levels within years occurred during the summer months in animals collected above 8,500 feet elevation. Regression analyses of muscle Cs-137 versus elevation indicated significant correlations. Evidence indicated a high degree of correlation between Cs-137 levels in vegetation and deer. It was concluded that the degree of foliage contamination and food habits were the most important factors contributing to Cs-137 burdens in deer. A Cs-137/K discrimination factor between the diet and muscle of 0.9 was estimated from the rumen samples. Neither sex nor age produced statistically significant variations in muscles Cs-137. Inhalation, the drinking of surface waters, and the ingestion of snow were minor sources of Cs-137 intake by deer in comparison to the ingestions of forage.
May 1965.
Includes bibliographical references (pages 131-142).
Author's name on piece is Floyd Ward Whicker.
Covers not scanned.
Print version deaccessioned 2021.