Concentrations and Dose Rate Estimates of 134, 137Cesium and 90Strontium in Small Mammals at Chornobyl, Ukraine

RONALD K. CHESSER, DERRICK W. SUGG, MICHAEL D. LOMAKIN, RONALD A. VAN DEN BUSSCHE,*# J. ANDREW DeWOODY, * CHARLES H. JAGOE, CHAM E. DALLAS, F. WARD WHICKER, MICHAEL H. SMITH, SERGEI P. GASHAK, IGOR V. CHIZEVSKY, VITALIJ V. LYABIK, ELENA G. BUNTOVA, KEVIN HOLLOMAN, and ROBERT J. BAKER*

Department of Genetics, University of Georgia, Athens, Georgia 30602, USA

Savannah River ecology Laboratory, Drawer E, Aiken, South Carolina 29802, USA

International Research and Development Agency, Kiev-1, PO Box 158, 252001, Ukraine

* Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, USA

# Department of Zoology, Oklahoma State University, Stillwater, Oklahoma 74078, USA

Department of Pharmacology and Toxicology, University of Georgia, Athens, Georgia 30602, USA

Department of Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523, USA

Chornobyl Scientific and Technical Center for International Research, Chornobyl, Ukraine

Abstract- Free-ranging mammals near the Chornobyl nuclear reactor are experiencing substantial radiation dose rates from intramuscular concentrations of 134, 137Cs and skeletal 90Sr. Radiocesium concentrations averaged 3,200 Bq/g of dry muscle, compared to a mean of 297 Bq 90Sr/g in bone for mammals in the Exclusion zone, a region of restricted human activity surrounding the reactor. Estimates of dose rates from intramuscular sources of radiocesium averaged 2.4 mGy/d within 8 km of the reactor and ranged as high as 60 mGy/d. Overall dose rates from internal 90Sr for mammals in the Exclusion Zone averaged 1.0 mGy/d, although doses to specific tissues are likely much higher. Mammals captured 30 km southeast of the reactor averaged only 2 Bq/g of muscle and were receiving an average of 1.4 μGy/d from internal radiocesium. Dramatic variation exists in the spatial pattern of radiocesium in areas immediately surrounding the reactor and within and between remediated and unremediated regions. The variance of 90Sr for taxa among cites was significantly less than that for 134, 137Cs. Thermoluminescent dosimeters placed on free-ranging mice showed that dose rates from external sources of radiation were much greater than the dose rates from internal sources of radiocesium. Estimated dose rates in very small areas of the Chornobyl region exceed those reported to impede reproductive success in mammals.

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