Radionuclide transfer to animal products: revised recommended transfer coefficient values

A compilation has been undertaken of data which can be used to derive animal product transfer coefficients for radionuclides, including an extensive review of Russian language information. The resultant database has been used to provide recommended transfer coefficient values for a range of radionuclides to (i) cow, sheep and goat milk, (ii) meat (muscle) of cattle, sheep, goats, pigs and poultry and (iii) eggs. The values are used in a new IAEA handbook on transfer parameters which replaces that referred to as ‘TRS 364’. The paper outlines the approaches and procedures used to identify and collate data, and assumptions used. There are notable differences between the TRS 364 ‘expected’ values and the recommended values in the revised Handbook from the new database. Of the recommended values, three milk values are at least an order of magnitude higher than the TRS 364 values (Cr, Pu (cow) Pu (sheep)) and one milk value is lower (Ni (cow)). For meat, four values (Am, Cd, Sb (beef) I (pork)) are at least an order of magnitude higher than the TRS 364 values and eight values are at least an order of magnitude lower (Ru, Pu (beef), Ru, Sr, Zn (sheep), Ru, Sr (pork), Mn (poultry)). Many data gaps remain.     

A global assessment of chromium pollution using sperm whales (Physeter macrocephalus) as an indicator species

Chromium (Cr) is a well-known human carcinogen and a potential reproductive toxicant, but its contribution to ocean pollution is poorly understood. The aim of this study was to provide a global baseline for Cr as a marine pollutant using the sperm whale (Physeter macrocephalus) as an indicator species. Biopsies were collected from free-ranging whales around the globe during the voyage of the research vessel The Odyssey. Total Cr levels were measured in 361 sperm whales collected from 16 regions around the globe detectable levels ranged from 0.9 to 122.6 μg Cr g tissue⁻¹ with a global mean of 8.8 ± 0.9 μg g⁻¹. Two whales had undetectable levels. The highest levels were found in sperm whales sampled in the waters near the Islands of Kiribati in the Pacific (mean = 44.3 ± 14.4) and the Seychelles in the Indian Ocean (mean = 19.5 ± 5.4 μg g⁻¹). The lowest mean levels were found in whales near the Canary Islands (mean = 3.7 ± 0.8 μg g⁻¹) and off of the coast of Sri Lanka (mean = 3.3 ± 0.4 μg g⁻¹). The global mean Cr level in whale skin was 28-times higher than mean Cr skin levels in humans without occupational exposure. The whale levels were more similar to levels only observed previously in human lung tissue from workers who died of Cr-induced lung cancer. We conclude that Cr pollution in the marine environment is significant and that further study is urgently needed.     

Sorption of alkylphenols on Ebro River sediments: comparing isotherms with field observations in river water and sediments

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f_OC) ranging from 0.0035 to 0.082 g_OC g⁻¹. All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations.     

New best estimates for radionuclide solid–liquid distribution coefficients in soils. Part 3: miscellany of radionuclides (Cd,Co, Ni,Zn, I,Se, Sb,Pu, Am,and others)

New best estimates for the solid–liquid distribution coefficient (K_d) for a set of radionuclides are proposed, based on a selective data search and subsequent calculation of geometric means. The K_d best estimates are calculated for soils grouped according to the texture and organic matter content. For a limited number of radionuclides this is extended to consider soil cofactors affecting soil–radionuclide interaction, such as pH, organic matter content, and radionuclide chemical speciation. Correlations between main soil properties and radionuclide K_d are examined to complete the information derived from the best estimates with a rough prediction of K_d based on soil parameters. Although there are still gaps for many radionuclides, new data from recent studies improve the calculation of K_d best estimates for a number of radionuclides, such as selenium, antimony, and iodine.     

Review of Russian language studies on radionuclide behaviour in agricultural animals: 3. Transfer to muscle

Over 150 publications reporting studies conducted in the former USSR were reviewed to provide transfer coefficients (F_f) to the muscle of domestic animals from experiments using chronic administration, often for long timescales in large scale experiments. Only a few of these studies were made available in the English language literature or taken into account in international reviews. The values derived have been compared with expected values reported by the IAEA's Handbook of parameter values for the prediction of radionuclide transfer in temperate environments (TRS 364) where possible. The information presented here has been used in the current updating of parameters recommended for environmental assessments by the IAEA. Many of the reported values are for Sr due to the Mayak accident and Cs due to the Chernobyl accident. Nevertheless, the reported data for a wide range of radionuclides, in particular for Ru, Sb, and Zn markedly improve the extent of available data.     

Spatial distribution of uranium and thorium in the surface soil around proposed uranium mining site at Lambapur and its vertical profile in the Nagarjuna Sagar Dam

The understanding and evaluation of the possible interactions of various naturally occurring radionuclides in the world's third largest man-made dam, Nagarjuna Sagar located in Andhra Pradesh, India and built on river Krishna assumed significance with the finding of uranium deposits in locations near the dam. For the present work, surface soil samples from the mineralized area of Lambapur, Mallapuram, Peddagattu and sediment core samples from the Nagarjuna Sagar dam were analyzed for naturally occurring radionuclides namely uranium and thorium using gamma spectrometric technique. Also toxic elements lead and chromium were analysed by the Energy Dispersive X-ray Fluorescence Spectrometer (EDXRF) technique. Surface soil samples show a variation from 25 to 291 Bq/kg (2.02–23.5 mg/kg) for ²³⁸U and 32–311 Bq/kg (7.9–76.9 mg/kg) for ²³²Th. U/Th concentration ratio in surface soil samples ranged from 0.19 to 0.31 and was found comparable with the nation wise average of 0.26. The study of sediment core samples reflected higher U/Th concentration ratio of 0.30–0.33 in the bottom section of the core as compared to 0.22–0.25 in the upper section. The concentration ratio in the upper section of the core was similar to the ratio 0.23 found in the western Deccan Basalt region through which the river originates. A higher concentration of lead and chromium was observed in the upper section of the core compared to bottom section indicating the impact of river input on the geochemical character of dam sediment.     

Review of Russian-language studies on radionuclide behaviour in agricultural animals: part 4. Transfer to poultry

Data on radionuclide transfer to domestic chickens and ducks obtained from research performed in the former Soviet Union were reviewed to provide transfer coefficient values (Ff) to poultry and edible egg contents. The majority of the data are from experiments with ⁹⁰Sr and ¹³⁷Cs, reflecting the importance of these radionuclides after global fallout and major radiation accidents. Data for ³H, ⁵⁴Mn, ⁵⁹Fe, ⁶⁰Co, ²²Na ⁶⁵Zn, ¹³¹I and U are also given. The values derived have been compared with those in the current IAEA Handbook of parameter values for the prediction of radionuclide transfer in temperate environments (TRS 364) and the recent revision which incorporates the values from this paper. The Russian-language data give improved estimates for many radionuclides and the revised handbook is now based on the better quality data given for chronic administration.     

Structural-functional organization of lower vegetation layers in tree communities of the upper timberline ecotone in the Polar Urals

Typologically identical (dwarf birch-herb-dwarf shrub-moss) open and closed larch forests growing on the same altitudinal transect have proved to differ in the structural-functional organization of lower vegetation layers. Coverage, general species composition, and species richness of the herb-dwarf shrub layer are higher in the open forest than in the closed forest. Correlations between individual species of vascular plants weaken upon transition from the open to the closed forest. Conversely, the coverage of the lichen-moss layer increases in the closed forest, which contributes to its role as a factor of selection of vascular plant species against the background of the prevailing influence of the tree layer.