Elements of Carbon Balance in Oligotrophic Bogs

Elements of carbon balance of oligotrophic bogs were studied using an example of the landscape profile of the Klyuch River in 1998–2000. Carbon balance was preliminarily calculated taking into account the biological productivity, release of carbon dioxide and methane, and carbon outflow with bog waters. Based on the data obtained on the carbon inflow and outflow, the conclusion was made concerning the progressive peat formation in the region studied.     

Morphogenesis of the Procumbent Life Form in Siberian Stone Pine at the Timberline in the Western Sayan Mountains

The morphology and development are described for Siberian stone pine (Pinus sibiricaDu Tour) growing at the timberline in the Western Sayan Mountains. Throughout ontogeny, these plants have a short stem trailing in an approximately horizontal direction. Maximal longevity and viability are characteristic of basal branches, which are able to root and produce vegetative generations. This allows these plants to be classified with the procumbent tree life form, in which the clones of most adaptive genotypes not only survive under extreme environmental conditions, but can also reproduce vegetatively.     

Variability in background levels of surface soil radionuclides in the vicinity of the US DOE waste isolation pilot plant

Concentrations of radionuclides were measured in soils from a grid of locations surrounding the US Department of Energy Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico and from a grid on a reference site approximately 20 km southeast of the WIPP site. Each of the two grids has 16 sampling locations (grid nodes) systematically distributed within an area of 16.580 ha. Sampling was conducted prior to the arrival of the first waste shipment at WIPP. Thus, the 137Cs and 23,240Pu in the soil are expected to have been deposited as global fallout, although the Gnome Site, 8.8 km southwest of the WIPP, is also a potential source of 239,240Pu and fission products. The reference grid has significantly higher concentrations of fallout and natural radionuclides than the WIPP grid. Up to 80% of the total variability in radionuclide concentrations across the two grids is attributable to differences between grid nodes. Differences between replicates within a location account for 44-50% of the variability in concentrations of the uranium isotopes, but only 11-17% of the variability in the concentrations of the other radionuclides. Samples having similar abundance of radionuclides were spatially aggregated across the terrain. The activity concentrations of the radionuclides were strongly correlated with the concentrations of Al and Pb, and with the percentages of sand, silt and clay in the soil. Normalizing radionuclide concentrations to the concentration of Al or percent fine particles can help adjust for differences in soil textures among samples and facilitate the detection of gradients or temporal changes in soil concentrations.     

Daily ingestion of 232Th, 238U, 226Ra, 228Ra and 210Pb in vegetables by inhabitants of Rio de Janeiro City

The concentrations of the naturally occurring radionuclides 232Th, 238U, 210Pb, 226Ra and 238Ra were determined in the vegetables (leafy vegetables, fruit, root, bean and rice) and derived products (sugar, coffee, manioc flour, wheat flour, corn flour and pasta) consumed most by the adult inhabitants of Rio de Janeiro City. A total of 88 samples from 26 different vegetables and derived products were analyzed. The highest contribution to radionuclide intake arises from bean, wheat flour, manioc flour, carrot, rice, tomato and potato consumption. The estimated daily intakes due to the consumption of vegetables and derived products are 1.9 mBq of 232Th (0.47 microg), 2.0 mBq of 238U (0.17 microg), 19 mBq of 236Ra, 26 mBq of 210Pb and 47 mBq of 228Ra. The estimated annual effective dose due to the ingestion of vegetables and their derived products with the long-lived natural radionuclides is 14.5 microSv. Taking into account literature data for water and milk from Rio de Janeiro the dose value increases to 29 microSv, with vegetables and derived products responsible for 50% of the dose and water for 48%. 210Pb (62%) and 228Ra (24%) were found to be the main sources for internal irradiation.     

Radiation doses of Swiss population from external sources

The outdoor radiation exposure of the population in Switzerland from external sources results from cosmic background as well as from natural and artificial ground radiation. The geographical distribution of these components and of the total dose rate are represented on maps consisting of 2 kmx2 km grid cells. The average dose rate on Swiss territory outdoors is 147 nSv/h (1.29 mSv/a). The distributions are then related to the population density distribution by GIS application. The population is exposed to an average dose rate of 108 nSv/h (0.95 mSv/a) per capita which is just below the threshold for man-made dose rate given by national regulation. The lower value (relative to the country average 147 nSv/h) arises from the fact that most of the population lives north of the Alps where the lithology is dominated by rocks of relatively low radioactivity and where the cosmic radiation is low relative to the Alps.     

Post-irrigation impact of domestic sewage effluent on composition of soils,crops and ground water--a case study

Long-term irrigation with sewage water adds large amounts of carbon, major and micro- nutrients to the soil. We compared the spatial distribution of N, P, K and other micronutrients and toxic elements in the top 0.6 m of an alluvial soil along with their associated effects on the composition of crops and ground waters after about three decades of irrigation with domestic sewage effluent as a function of distance from the disposal point. Use of sewage for irrigation in various proportions improved the organic matter to 1.24-1.78% and fertility status of soils especially down to a distance of 1 km along the disposal channel. Build up in total N was up to 2908 kg ha(-1), available P (58 kg ha(-1)), total P (2115 kg ha(-1)), available K (305 kg ha(-1)) and total K (4712 kg ha(-1)) in surface 0.15 m soil. Vertical distribution of these parameters also varied, with most accumulations occurring in surface 0.3 m. Traces of NO3-N (up to 2.8 mg l(-1)), Pb (up to 0.35 mg l(-1)) and Mn (up to 0.23 mg l(-1)) could also be observed in well waters near the disposal point thus indicating initiation of ground water contamination. However, the contents of heavy metals in crops sampled from the area were below the permissible critical levels. Though the study confirms that the domestic sewage can effectively increase water resource for irrigation but there is a need for continuous monitoring of the concentrations of potentially toxic elements in soil, plants and ground water.     

The Outcome of Northern Fur Seal Harvesting: The Results of Calibration of Mathematical Models Based on Observation Data (the Example of Tyulenii Island Population)

Tendencies in the dynamics of harvested northern fur seal (Callorhinus ursinus) population on the Tyulenii Island have been analyzed in detail. The results show that retardation of reproduction (decrease in the numbers of pups) and decline in the survival of young females (up to 3 years of age) by the late 1980s resulted in a reduction of the total number of females and a significant increase in the proportion of older females. This tendency changed during the later observation period (after 1988–1989) due to increase in the survival of young females: the female population has gradually recovered, with the proportion of young females increasing at the expense of old females (aged over 10 years). The age composition of males has also changed: the proportion of young animals has decreased, while that of large mature males (bulls) has increased. Moreover, the number of bulls continues to increase and has already exceeded the level that formerly provided for the well-being of the population. This, a paradoxical situation has arisen: the numbers of females and bulls are increasing, whereas pup production remains at a low level.

     

Small island developing states: coastal systems, global change and sustainability

The intent of this paper is to place the concepts of exposure, vulnerability, resilience and risk in the context of the consequences of global change for the sustainable development of small island developing states (SIDS). Many such states face a number of global climate change risks, such as an increase in the proportion of more intense storms, along with other global change threats that include energy security and costs. All these threats come on top of local development threats, such as increased run-off, often with increasing levels of contaminants due to unsustainable agricultural and industrial practices. When taken together, the resulting pressures on islands and their communities lead to significant increases in vulnerability to change due to reduced resilience to these changes. Vulnerability is also increasing as a result of contemporary processes that heighten the exposure of material and other assets. The capacity to address hazard risk also influences vulnerability. This includes the level of awareness of coastal hazards and exposure, and access to critical life support infrastructure, especially for people living in hazard-prone areas. Vulnerability and resilience are considered to be important integrating concepts when managing the local consequences of global changes. There are many initiatives that will help reduce the vulnerability and enhance the resilience of SIDS to such changes. These include improving risk knowledge and coastal resource and land use management, while also strengthening socio-economic systems and livelihoods. In this way, managing global change can be closely aligned with local development and humanitarian processes, thereby enhancing the overall sustainability of development processes and outcomes.     

Radionuclide contamination of sediment deposits in the Ob and Yenisey estuaries and areas of the Kara Sea

The Ob and Yenisey rivers are major contributors to total riverine discharge to the Arctic Ocean. Several large nuclear facilities discharge into these rivers, which could affect actual and potential discharges of radionuclides to the Arctic region. This article presents new radionuclide concentration and grain-size data resulting from analyses of several sediment samples collected during research cruises in the Ob and Yenisey estuaries and adjacent areas during 2000 and 2001. Results indicate that discharges from the main nuclear facilities do not constitute a major contribution to the level of radioactive contamination in the marine areas studied, though Co-60 was detected at low concentrations in some sediment horizons. However, the aggregate contamination from different sources is not radioecologically significant in sediments within the study area, maximum Cs-137 levels being approximately 80 Bq kg(-1) dry weight.     

Reconstruction of atmospheric concentrations and deposition of uranium and decay products released from the former uranium mill at Uravan, Colorado

Radionuclide concentrations in air from uranium milling emissions were estimated for the town of Uravan, Colorado, USA and the surrounding area for a 49-yr period of mill operations beginning in 1936 and ending in 1984. Milling processes with the potential to emit radionuclides to the air included crushing and grinding of ores; conveyance of ore; ore roasting, drying, and packaging of the product (U(3)O(8)); and fugitive dust releases from ore piles, tailings' piles, and roads. The town of Uravan is located in a narrow canyon formed by the San Miguel River in western Colorado. Atmospheric transport modeling required a complex terrain model. Because historical meteorological data necessary for a complex terrain model were lacking, meteorological instruments were installed, and relevant data were collected for 1 yr. Monthly average dispersion and deposition factors were calculated using the complex terrain model, CALPUFF. Radionuclide concentrations in air and deposition on ground were calculated by multiplying the estimated source-specific release rate by the dispersion or deposition factor. Time-dependent resuspension was also included in the model. Predicted concentrations in air and soil were compared to measurements from continuous air samplers from 1979 to 1986 and to soil profile sampling performed in 2006. The geometric mean predicted-to-observed ratio for annual average air concentrations was 1.25 with a geometric standard deviation of 1.8. Predicted-to-observed ratios for uranium concentrations in undisturbed soil ranged from 0.67 to 1.22. Average air concentrations from 1936 to 1984 in housing blocks ranged from about 2.5 to 6 mBq m(-3) for (238)U and 1.5 to 3.5 mBq m(-3) for (230)Th, (226)Ra, and (210)Pb.