Toxicities and tolerances of Cd, Cu, Pb and Zn in a primary producer (Isochrysis galbana) and in a primary consumer (Perna viridis)

Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC(50) and 24-h LC(50) of these heavy metals were determined in the brown alga and mussel, respectively. The EC(50) values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC(50) values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC(50) values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC(50) and LC(50) values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied.     

Concentration measurements of 7Be at ground level air at Palermo, Italy-comparison with solar activity over a period of 21 years

Air activity concentrations of (7)Be in Palermo determined for the period January 1995-December 2002 by gamma-ray spectrometric analysis of particulate samples collected on paper filter by a high-volume sampler (approximately 900 m(3) h(-1)) are reported. The temporal behaviour of (7)Be concentration presents the same characteristics already observed in the measurements carried out over the previous 13-year (1982-1994) investigated period. The mean value of 5.06 mBq m(-3) obtained from the analysis of the 4636 particulate samples collected from 1982 to 2002 can be considered a representative value of (7)Be air concentration at ground level in our geographical zone. The comparison of long-term variation in the (7)Be concentrations with the cyclic solar activity-extended to the whole period of 21 years-confirms the inverse correlation between the two quantities.     

Soil-plant transfer of plutonium and americium in contaminated regions of Belarus after the Chernobyl catastrophe

Experimental data are presented for the soil to plant transfer of plutonium and americium into the main species of grass vegetation of Belarusian grasslands contaminated as a result of the Chernobyl catastrophe of 1986. The content of radionuclides in pore soil solutions and the total reserve of biologically available forms of plutonium and americium in rooting layers of different soil varieties have been established. The distribution coefficients of (239,240)Pu and 241Am between the solid phase and pore waters of soils have been evaluated. The migration ability and biological availability of radionuclides in soils with different structures of the absorbing complex have been analyzed for various landscape conditions. The dependence of soil to plant transfer of plutonium and americium on the content and composition of organic matter, and other characteristics of the soil complex has been studied. On the basis of these data, predictions of the contamination levels of the main grass species of natural and agricultural ecosystems by 241Am are presented.     

137Cs contamination in tea and yerba mate in South America

Gamma-ray spectra from more than 50 samples of food products available in stores of Buenos Aires city were measured using a germanium detector. Activity concentrations of 137Cs up to 10 Bq/kg were found in tea and yerba mate manufactured in Apóstoles, Argentina. Further measurements of tea leaves, yerba mate leaves and soils, all coming from a cultivated area in that region, also show the presence of 137Cs contamination. The results suggest that the area was fertilized with a product that originated in a region affected by the fallout from the Chernobyl nuclear plant accident.     

Lake fish as the main contributor of internal dose to lakeshore residents in the Chernobyl contaminated area

Two field expeditions in 1996 studied 137Cs intake patterns and its content in the bodies of adult residents from the village Kozhany in the Bryansk region, Russia, located on the shore of a drainless peat lake in an area subjected to significant radioactive contamination after the 1986 Chernobyl accident. The 137Cs contents in lake water and fish were two orders of magnitude greater than in local rivers and flow-through lakes, 10 years after Chernobyl radioactive contamination, and remain stable. The 137Cs content in lake fish and a mixture of forest mushrooms was between approximately 10-20 kBq/kg, which exceeded the temporary Russian permissible levels for these products by a factor of 20-40. Consumption of lake fish gave the main contribution to internal doses (40-50%) for Kozhany village inhabitants Simple countermeasures, such as Prussian blue doses for dairy cows and pre-boiling mushrooms and fish before cooking, halved the 137Cs internal dose to inhabitants, even 10 years after the radioactive fallout.     

Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides

Daily dietary intakes of two naturally occurring long-lived radionuclides, 232Th and 238U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232Th and 12.7 mBq for 238U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 ug) 232Th and 23.6 mBq (1.9 ug) 238U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232Th and 15.6 mBq 238U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232Th and 238U were calculated to be 0.34 and 0.20 microSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 microSv to man from the natural radiation sources as proposed by UNSCEAR.     

Radiocesium accumulation in mosses from highlands of Serbia and Montenegro: chemical and physiological aspects

The aim of this work was (i) to determine the activity levels of 137Cs in mosses from highland ecosystems of Serbia and Montenegro, (ii) to find out if radiocesium is associated with essential biomacromolecules, and (iii) to investigate 137Cs distribution among intracellular compartments. It was found that biomolecules of mosses do not bind significant amounts of radiocesium (2.3-3.3% of the absorbed 137Cs), a behavior that was independent of the moss species. Cellular fractionation of mosses showed that membranes are the primary 137Cs-binding sites at the cellular level. They contained 26.1-43.1% of the initial radiocesium activity. It seems that 137Cs-binding molecules in different mosses are of similar chemical nature, and their distribution between various cellular compartments is not species specific.     

The Spatiotemporal Structure of Rodent Populations in the Steppe Zone of Western Siberia

The spatial structure of populations has been studied in two rodent species inhabiting the subzone of meadow steppes of the steppe zone of Omsk oblast: the narrow-sculled vole (Microtus gregalis Pall.) and steppe lemming (Lagurus lagurus Pall.). Their populations are represented by combinations of territorial family groups whose structure and spatial distribution vary by season depending on population density, the phase of the population cycle, and the status of their members in the population. In the areas cohabited by M. gregalis and L. lagurus, the pattern of territory use and the rhythm of animal activity during the day depend primarily on their total density: under conditions of low density, the population groups of both species are spatially separated; at increased density, they are distributed with respect to the pattern of daily activity. Both species jointly use part of the territory but at different times of day: M. gregalis, mainly at night and in the morning; L. lagurus, in the daytime.     

Assessment of Soil Cover Degradation and Desertification in Northern Lowland Dagestan

New principles of the assessment of soil cover degradation and desertification, the scale and intensity of destructive processes manifestation are determined.     

Ordination of Plant Communities in Forest Biogeocenoses under Conditions of Air Pollution in the Northern Kola Peninsula

The species diversity and structure of the tree, herb–dwarf shrub, and moss–lichen layers in the biogeocenoses (BGCs) of pine forests of the Kola Peninsula were analyzed in the zone affected by the Pechenganikel Combined Works. Relationships of the diversity of phytocenoses with the amount of atmospheric fallout and the concentrations of accessible compounds of polluting elements (nickel and copper) and nutrients (potassium, magnesium, and nitrogen) in forest litters were revealed.