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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 134,137Sr for taxa among sites 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. [ABSTRACT FROM AUTHOR]

Samples of crucian carp (Carassius carassius) and sediments collected from 14 ponds within and outside the 30 km exclusion zone southeastof Chernobyl were analyzed for radiocesium; major anions and cationsin water were determined for each pond, and other atmospherically- transported pollutants (Pb and Hg) were measured in fish muscle. Up to20 sediment samples were collected from each pond. Median sediment radiocesium was -1 dry mass in all ponds, but somesamples contained up to 11 Bq g-1 dry mass. The distribution of radiocesium was very patchy, and could vary over 100% in samples collected a few meters apart. Fish muscle radiocesium ranged from below detection up to 8.2 Bq g-1 dry mass and varied significantly among ponds. All Carassius muscle analyzed contained detectable Hg (0.03 to 1.28 mug g-1 dry mass), and most containeddetectable Pb (up to 1.76mug g-1 dry mass). Water chemistry was a poor predictor of fish contaminant burden, possibly due to the extreme patchiness of the contaminant distribution. Fish size was correlated with muscle Cs content in some ponds, and negatively correlated with muscle Pb concentration. The distributions of radioactive and non-radioactive contaminants were not significantly correlated. [ABSTRACT FROM AUTHOR]