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A number of assessment frameworks have been proposed to provide a mechanism to demonstrate protection of the environment from ionising radiation. Whilst some of these are being used for assessment purposes they have largely not been validated against field measurements. In this paper we compare the predictions of transfer parameters recommended by one of these frameworks (FASSET) with observed whole-body 90Sr and radiocaesium activity concentrations in a range of mammal and invertebrate species sampled within the Chernobyl exclusion zone. Predicted activity concentrations were generally within the observed ranges and mean predictions for reference organisms were similar to, or circa one order of magnitude higher than, the observed means. However, some predictions were more than one order of magnitude lower than observed values. No data were available to test predictions for the other radionuclides released by the Chernobyl accident. In a separate paper the outputs of this assessment will be used to estimate doses to reference organisms and compare these to observed radiation induced effects reported within the Chernobyl zone. [ABSTRACT FROM AUTHOR]

Environmental monitoring programs often measure contaminant concentrations in animal tissues consumed by humans (e.g., muscle). By comparison, demonstration of the protection of biota from the potential effects of radionuclides involves a comparison of whole-body doses to radiological dose benchmarks. Consequently, methods for deriving whole-body concentration ratios based on tissue-specific data are required to make best use of the available information. This paper provides a series of look-up tables with whole-body:tissue-specific concentration ratios for non-human biota. Focus was placed on relatively broad animal categories (including molluscs, crustaceans, freshwater fishes, marine fishes, amphibians, reptiles, birds and mammals) and commonly measured tissues (specifically, bone, muscle, liver and kidney). Depending upon organism, whole-body to tissue concentration ratios were derived for between 12 and 47 elements. The whole-body to tissue concentration ratios can be used to estimate whole-body concentrations from tissue-specific measurements. However, we recommend that any given whole-body to tissue concentration ratio should not be used if the value falls between 0.75 and 1.5. Instead, a value of one should be assumed. [ABSTRACT FROM AUTHOR]

Few data are available to quantify the transfer of both natural and anthropogenic radionuclides to detritivorous invertebrates to facilitate estimation of the internal dose to such biota in models used to assess radiation exposure. To enhance the available data, activity concentrations of 137Cs, 40K, 90Sr, 239 + 240Pu, 241Am, 235U and 238U were measured in ants ( Formicidae) and corresponding undisturbed soil collected from the Zlatibor mountain in Serbia and ant/soil concentration ratios (CR) calculated. The 241Am concentration ratios for ants were fourfold higher than those calculated for ants in a previous study whereas they are similar to the more numerous data previously reported for a range of detritivorous invertebrates in other studies. CR values for 137Cs in ants were similar to the few other reported values and slightly lower than those for a range of detritivorous invertebrates. Those for 239 + 240Pu were slightly higher than those for ants in two other studies but they were close to upper limit of a range of data reported for detritivorous invertebrates. All the CR values will be included in a future revision of the ERICA Tool database and will particularly improve the information available for uranium. [ABSTRACT FROM AUTHOR]

The uptake of 137Cs and 90Sr by six varieties of spring wheat (Triticum aestivum) was compared in field trials on land contaminated by the Chernobyl accident. All the experimental varieties are officially adopted for agricultural use in Belarus and are used in large-scale production. Under identical conditions of nutrition, the productivity of the varieties varied significantly by a factor of 1.3. The extent of 137Cs and 90Sr accumulation by wheat grain, quantified as the concentration ratio, differed between the varieties by as much as a factor of 1.6, for both radionuclides. There was a significant linear positive correlation between the 90Sr activity concentration in grain and straw, and the calcium concentration. The correlation between 137Cs and potassium was not significant. The results suggest that certain varieties of spring wheat used in normal agricultural practice accumulate less 137Cs and 90Sr into grain than others. Some spring wheat varieties accumulated relatively less 137Cs, but did not accumulate less 90Sr. One variety, Quattro, had a significantly lower uptake of both 90Sr (for grain) and 137Cs (for both grain and straw) than that of the other varieties tested. The reduction efficiency achieved by the use of these varieties, however, is not as high as that achieved by soil amelioration techniques in the past. Nevertheless, since there are no additional costs or production losses associated with these varieties, their use in the contaminated areas is worth considering as a simple, practical, and effective contribution to reducing the uptake of both 90Sr and 137Cs and allowing farmers to produce food-grade grain. [ABSTRACT FROM AUTHOR]

The effect of RADEKONT (a natural clinoptilolite modified by hexacyanoferrate) on 137Cs uptake into meat was tested in experiments with broiler chickens. Three experiments determined the influence of RADEKONT on radiocaesium transfer after single or repeated applications of artificially contaminated feed mixture and one experiment investigated the effect of RADEKONT when feeding a mixture containing wheat contaminated by the Chernobyl fallout. Independent of the effect of RADEKONT, the uptake of radiocaesium was faster in leg meat than in breast meat. Reduction factors (137Cs transfer without the RADEKONT additive compared with those observed after supplementation of the additive into the feed mixture) of 1.1–1.3 and 1.2–2.3, respectively, were achieved after single and repeated administrations of artificially contaminated feed. No significant differences in reduction between breast and leg meat were observed. RADEKONT was more effective when the chickens were fed with Chernobyl-contaminated wheat (reduction factors of up to 3.7) than an artificial 137Cs source. RADEKONT as a supplement during the decontamination period decreased the biological half-life of 137Cs to less than 1 day. The timing of the application of RADEKONT might be important in determining its effectiveness, especially in young, rapidly growing chickens. [ABSTRACT FROM AUTHOR]

The distribution and biological half-life of radiocaesium (137Cs) in broiler chickens after three oral applications (in course of 1 day at the age of 14 days) of artificially contaminated feed mixture were studied. There was a rapid uptake of the orally administered 137Cs (within a few hours) and also a rapid loss of 137Cs which varied in the different organs (the initial biological half-life was: liver 0.6 day, intestine 0.6 day, breast meat 2 days, leg meat 1.2 days). More than one-half of the total administered 137Cs activity (55%) was excreted from the body within the 1st day after dosage, and after 14 days more than 90% had been excreted. The highest accumulation of 137Cs occurred in meat (50%–90%), and the proportion of total activity in breast and leg meat varied during decontamination. The transfer of radiocaesium from feed into the chicken body (measured as ratios of the 137Cs activity concentrations in the organ to the 137Cs activity concentration in the applied dose) 1 day after application was: 0.0220, 0.0294, 0.0216 and 0.0195 for breast meat, leg meat, intestine and liver, respectively. Significant differences between the values were demonstrated ( P<0.05) except between those of breast meat and intestine. For the first 3 days there was a higher proportion of 137Cs activity in leg meat, whereas from the 4th day a greater part of total activity was found in breast meat. The latter results were confirmed in a subsequent study. Data from this study suggest that if broiler chickens are contaminated by radiocaesium to a level of 5 kBq/chicken in the course of 1 day at the age of 14 days, then immediate feeding with uncontaminated feed mixture for 18 days should be effective in decontaminating the chicken's meat below the intervention levels for radiocaesium in animal products, i.e. below 1000 Bq ⋅ kg–1. [ABSTRACT FROM AUTHOR]

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Evidence from research in the Pripyat catchment, reviewed here, indicates that under the ecological conditions prevalent in this area, radiocaesium (137Cs) is highly mobile in both river water and poorly drained organic soils. Data collected at three different spatial and temporal scales demonstrate the effects of hydrological events on 137Cs mobility. During the period 1988-1994, 137Cs contamination in some poorly drained organic soils in the Pripyat catchment and in the milk from cows grazing on these soils aregenerally declining much faster than the radioactive half life. However, sharp increases in levels of 137Cs in both floodplainsoils and milk to 2-3 times that observed immediately after the initial deposition have been measured immediately after summer floods. The processes causing these observed changes have not yet been fully explained but the sites where enhanced 137Cs mobility has been detected are clearly associated with the spatial patterns of organic soils and river flooding. [ABSTRACT FROM AUTHOR]