R. Bojanowski

A comparison of doses from 137Cs and 210Po in marine food: A major international study

Radioactivity levels of natural 210Po and anthropogenic 137Cs in sea water and biota (fish and shellfish) have been estimated for the FAO fishing areas on the basis of measurements carried out in recent years. Collective doses resulting from seafood consumption are calculated for each FAO area using radioactivity data for water and biota. Good agreement is observed between the results calculated by these two methods, with the exception of the doses from 210Po via shellfish consumption. The collective effective dose commitment from 137Cs in marine food in 1990 has been estimated at 160 man Sv with an uncertainty of 50%. The corresponding dose from 210Po is 30000 man Sv with an estimated uncertainty of a factor of 5. The results confirm that the dominant contribution to doses derives from natural 210Po in fish and shellfish and that the contribution from anthropogenic 137Cs (mainly originating from nuclear weapons tests) is negligible.

Distribution and coassociations of selected metals in seals of the Antarctic.

Zinc, Cu, Cd, Pb, Ag, Ni, Co, Cr, Fe and Mn concentrations in some tissues of crabeater seal (Lobodon carcinophagus), leopard seal (Hydrurga leptonyx) and Weddell seal (Leptonychotes weddelli) from the Antarctic were determined. Distinct inter-tissue differences in metal concentrations in seals were observed; liver contained maximum levels of Zn, Cu, Ag and Mn, whilst kidney showed the highest levels of Cd, Ni and Co. Muscle was characterized by low concentrations of all the elements analyzed. The metal concentrations in the vertebrates analyzed were compared with those for organisms originating from various aquatic areas. Significant correlations were found between the levels of several of the metals analyzed, e.g. between renal and hepatic concentrations of Zn and Cd. Strong relationships between the hepatic concentrations of some metals were found, e.g. Cd-Zn. These two metals also showed a significant coassociation in their renal concentrations. The slope of the regression line for renal Cd/Zn was about three times higher than the hepatic one and this may reflect a relatively high Cd exposure, probably from specific food (squid and krill) provenance, of the seals analyzed.

Concentration of selected metals in penguins and other representative fauna of the Antarctica

Concentration of Zn, Cu, Cd, Pb, Ag, Co, Ni, Cr, Mn and Fe were determined in muscle and liver of three species of penguins and other animals of the antarctic region. Liver was characterized by maximum concentrations of all the metals analyzed. The element levels in the samples assayed are in keeping with those reported previously by other authors. It is assumed that specific food habits of penguins are mainly responsible for elevated Cd levels in livers of these birds.

Distribution of Plutonium in selected components of the Baltic ecosystem within the Polish economic zone

In the paper are presented and discussed results of measurements of plutonium isotopes in the Baltic Sea, sediments and biota following the Chernobyl accident. The average 239, 240Pu level of seawater was found to be 5 mBq m−3 of which 70% constituted filterable forms (<0.45 μm). Sea plants and benthic animals concentrated plutonium isotopes to varying degrees, the concentration factors ranging from 600 to 27100. Small differences were observed between plutonium levels of malacostraca and bivalvia collected in 1986 and 1987. Generally, the impact of Chernobyl-derived plutonium on the Baltic ecosystem within the Polish economic zone was insignificant.

Radiocaesium and Plutonium in Atlantic Surface Waters from 73 °N to 72 °S

During the recent Swedish Antarctic research Expedition (SWEDARP 89/89) samples of surface sea water were collected on board the Stena Arctica during steaming between Gothenburg, Sweden and the Antarctic Peninsula. Radio chemical separation was performed for radio caesium on 200 l samples and for plutonium on samples between 200 and 1500 1. The results are compared with those of the GEOSECS expedition in the North and South Atlantic in 1972–73 and the Polish expedition in 1977–78. They show that radio caesium has behaved rather conservatively and that the decrease in surface water concentrations during 16 years mainly is due to physical decay. On the other hand levels of 239+240Pu have decreased by a factor of 4–5 giving a half life of 7–8 years in open Atlantic surface waters.

Activity concentration of caesium-137 in seawater and plankton of the Pomeranian Bay (the Southern Baltic Sea) before and after flood in 1997

Activity coefficients of 137Cs determined during culminating flood waters in August 1997 in the estuary of the Oder River, discharging to the Pomeranian Bay as well as in the coastal and open-seawaters of the Bay, did not show enhanced levels of the nuclide as compared to those measured before the flood. It is thus concluded that the flood did not contribute to releasing the nuclide from eroded soil particles. The bioconcentration factors of 137Cs in the riverine plankton has been found to be one to two orders of magnitude higher than those determined in the Pomeranian Bay plankton.

The characterisation of an intertidal sediment from the Cumbrian coastline

The characterisation of an intertidal sediment, containing enhanced levels of radioactivity, collected from the Cumbrian coast of the U.K. by the Laboratory of the Government Chemist for the Department of the Environment is described. A wide variety of radiochemical and instrumental techniques were used including α-spectrometry, β-counting, liquid scintillation counting, γ-spectrometry, X-ray spectrometry and mass spectrometry. To derive mean values of the activity concentrations of radionuclides in the material, use was made of the technique developed by Woods and Munster. This technique first critically evaluates data for technical suitability. Then, to avoid excessive manipulation of data, calculation of the weighted (the statistical weighting is the inverse of the squared uncertainties, limited so that no one result contributes more than 50%) and unweighted means is performed, along with a χ2 test. If the value of χ2/(n−1) 2 determinations, 3 with 2 determinations and 2 with single determinations. Emphasis is placed where data appeared to be discrepant (e.g. 40K and 137Cs), where widely different measurement techniques were employed (e.g. the actinides), where there were analytical “difficulties” (e.g. uranium) or where the radionuclide is not commonly measured (e.g. 155Eu, 237Np and 241Pu). The material is now available to laboratories as a reference material and it is anticipated that it will be used to validate existing procedures and to research new methods of analysis.

137Cs, 40K and 210Po in marine mammals from the southern Baltic Sea

This study provides information on baseline concentrations of the radionuclides Cesium-137, Potassium-40 and Polonium-210 in sea mammals from the Baltic Sea. The radionuclides were analyzed in the liver, kidney and muscle of harbor porpoises, striped dolphins, and gray and ringed seals from the Polish coast by γ- and α-spectrometry. Median (137)Cs activities were 14.8, 13.2 and 23.2 Bq kg(-1) w.w. in the liver, kidney and muscles, respectively. Activities of (40)K and (210)Po in the respective tissues were found to be 79.1, 79.8 and 111 Bq kg(-1) for (40)K and 58.1, 59.2 and 32.9 Bq kg(-1) for (210)Po. The measured (137)Cs concentrations were extraordinarily high in comparison to those reported in sea mammals from other locations. However, dose assessments did not imply health effects from (137)Cs exposure in Baltic Sea mammals. Correlations between (137)Cs tissue activities and reported sea water concentrations highlight the potential use of marine mammals for biomonitoring purposes.

Determination of 89Sr and 90Sr in highly radioactive water from a nuclear power plant

Abstract The main criterion in assaying strontium radionuclides is to obtain radiochemically pure strontium sources for beta-particle counting. Nuclear power plant waters contain both 89 Sr and 90 Sr accompanied by many beta-particle and gamma-ray emitting fission and neutron-activation products. The latter activities can sometimes exceed those of strontium by a factor of 10 7 . Efficient purification procedures must be used to remove these products, preferably at an initial stage of analysis to reduce the radiation risk to personnel. A method has been developed in which a water sample is passed through a prefilter installed on top of an ion-exchange column filled with Dowex-50 resin in H + form. This prefilter is impregnated with ferrocyanides and manganese dioxide and retains most of the interfering radionuclides while the underlying cation-exchanger takes up strontium ions. A few additional purification steps result in a strontium salt that is free from other radioactivity.