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41.
Methodological Basis of Ecological Safety Standards for the Technogenic Impact of Mineral Resource Exploitation 总被引:1,自引:0,他引:1
A new methodological approach to the development of biological and technological safety standards for the impact of underground mining on the natural biota is proposed. 相似文献
42.
N. P. Kosykh N. P. Mironycheva-Tokareva A. M. Peregon E. K. Parshina 《Russian Journal of Ecology》2008,39(7):466-474
New experimental data on biological productivity of plant communities in oligotrophic and mesotrophic bogs of the middle taiga
subzone over the past five years are presented. The relationship between net primary production and the stock of live phytomass
is estimated. The stock of necromass in oligotrophic bog ecosystems increases from west to east, while the stock of live phytomass
and net primary production decrease. 相似文献
43.
P.P. Povinec H. Bokuniewicz W.C. Burnett J. Cable M. Charette J.-F. Comanducci E.A. Kontar W.S. Moore J.A. Oberdorfer J. de Oliveira R. Peterson T. Stieglitz M. Taniguchi 《Journal of environmental radioactivity》2008,99(10):1596
Results of groundwater and seawater analyses for radioactive (3H, 222Rn, 223Ra, 224Ra, 226Ra, and 228Ra) and stable (D and 18O) isotopes are presented together with in situ spatial mapping and time series 222Rn measurements in seawater, direct seepage measurements using manual and automated seepage meters, pore water investigations using different tracers and piezometric techniques, and geoelectric surveys probing the coast. This study represents first time that such a new complex arsenal of radioactive and non-radioactive tracer techniques and geophysical methods have been used for simultaneous submarine groundwater discharge (SGD) investigations. Large fluctuations of SGD fluxes were observed at sites situated only a few meters apart (from 0 cm d−1 to 360 cm d−1; the unit represents cm3/cm2/day), as well as during a few hours (from 0 cm d−1 to 110 cm d−1), strongly depending on the tidal fluctuations. The average SGD flux estimated from continuous 222Rn measurements is 17 ± 10 cm d−1. Integrated coastal SGD flux estimated for the Ubatuba coast using radium isotopes is about 7 × 103 m3 d−1 per km of the coast. The isotopic composition (δD and δ18O) of submarine waters was characterised by significant variability and heavy isotope enrichment, indicating that the contribution of groundwater in submarine waters varied from a small percentage to 20%. However, this contribution with increasing offshore distance became negligible. Automated seepage meters and time series measurements of 222Rn activity concentration showed a negative correlation between the SGD rates and tidal stage. This is likely caused by sea level changes as tidal effects induce variations of hydraulic gradients. The geoelectric probing and piezometric measurements contributed to better understanding of the spatial distribution of different water masses present along the coast. The radium isotope data showed scattered distributions with offshore distance, which imply that seawater in a complex coast with many small bays and islands was influenced by local currents and groundwater/seawater mixing. This has also been confirmed by a relatively short residence time of 1–2 weeks for water within 25 km offshore, as obtained by short-lived radium isotopes. The irregular distribution of SGD seen at Ubatuba is a characteristic of fractured rock aquifers, fed by coastal groundwater and recirculated seawater with small admixtures of groundwater, which is of potential environmental concern and has implications on the management of freshwater resources in the region. 相似文献
44.
Kalbande DM Dhadse SN Chaudhari PR Wate SR 《Environmental monitoring and assessment》2008,138(1-3):233-238
Abstract Industrial development and consumption of petroleum products leads to increase air pollution levels especially in
urban and industrial areas. Heavy metal components associated with air pollutants have far reaching effects with respect to
economic and ecological importance of pollens. The pollens are male reproductive organs of the plant and travel through air
from flower to flower for pollination purpose. During this period they are exposed to air pollutants. Present investigation
thus pertains to study of effect of air pollutants on pollens especially biosorption and bioaccumulation of heavy metals.
The pollens of three commonly occurring plants namely Cassia siamea, Cyperus rotundus, Kigelia pinnata have been studied from the NH-6 of Nagpur city, India. The pollens exposed to polluted air showed the presence of higher
concentrations of Ca, Al and Fe as compared to unexposed pollens. Higher concentration of these metals was observed in Cyperus rotundus followed by Cassia siamea and Kigelia pinnata. These results indicate that pollens act as good indicator of air pollution giving results in short time of exposure of 5–10 h.
Apart from this, it is also reported that some of these metals play crucial role in the metabolic activity in pollens for
example Calcium is necessary for growth of pollen tube and other metabolic activities in pollens. The presence of these metals
in pollens may also enhance the allergenicity of the pollens. Similarly accumulation of heavy metals may also deteriorate
the quality of pollen for their economical use. The viability of pollen is also affected by these pollutants in sensitive
species leading to impairment of their fertility. 相似文献
45.
Clausen L Arildskov NP Larsen F Aamand J Albrechtsen HJ 《Journal of contaminant hydrology》2007,89(3-4):157-173
The worldwide used herbicide dichlobenil (2,6-dichlorobenzonitrile) has resulted in widespread presence of its metabolite 2,6-dichlorobenzamide (BAM) in surface water and groundwater. To evaluate the potential for natural attenuation of this BAM pollution in groundwater, we studied the degradation of BAM and dichlobenil in 16 samples of clayey till, unconsolidated sand and limestone, including sediments from both oxidized and reduced conditions. The degradation of dichlobenil occurred primarily in the upper few meters below surface, although dichlobenil was strongly sorbed to these sediments. However, the degradation of dichlobenil to BAM could not be correlated to either sorption, water chemistry, composition of soils or sediments. Degradation of dichlobenil to BAM was limited (<2% degraded) in the deeper unsaturated zones, and no degradation was observed in aquifer sediments. This illustrates, that dichlobenil transported to aquifers does not contribute to the BAM-contamination in aquifers. A small, but significant degradation of BAM was observed in the upper part of the unsaturated zones in sandy sediments, but no degradation was observed in the clayey till sediment or in the deeper unsaturated zones. The insignificant degradation of BAM in aquifer systems shows that BAM pollution detected in aquifers will appear for a long time; and consequently the potential for natural attenuation of BAM in aquifer systems is limited. 相似文献
46.
Adamo P Crisafulli P Giordano S Minganti V Modenesi P Monaci F Pittao E Tretiach M Bargagli R 《Environmental pollution (Barking, Essex : 1987)》2007,146(2):392-399
Lobes of the lichen Pseudevernia furfuracea (L.) Zopf and shoots of the moss Hypnum cupressiforme Hedw. were subjected to different treatments (water washing, oven drying, HNO3 washing, NH4-oxalate extraction) to assess the influence of vitality on accumulation efficiency, during a 6-week exposure in bags in two Italian cities, Trieste and Naples. No trend emerged between treatments, in terms of accumulation ability, for major and trace elements. Only water-washed lichens showed an increased C and N content after exposure in both cities. Element concentrations generally reached higher values in mosses than in lichens, especially for Al, Fe, and Zn (both cities), and for Cu, Mg and Na (Naples). Surface development strongly influenced accumulation capacity of the biomonitors. Quartzose and cation exchange filters revealed, on a weight basis, a poor performance. In urban environments, surface interception of atmospheric particulate seems to play a major role in accumulation, irrespective of organism vitality. 相似文献
47.
Bhattacharyya P Chakrabarti K Chakraborty A Nayak DC Tripathy S Powell MA 《Chemosphere》2007,66(9):1789-1793
The importance of the use of potassium in agriculture is increasing in South Asia for making most productive use of the nutrient in terms of economic returns. Nutrient supply traditionally by cattle manure is constrained by its insufficient availability. Municipal waste compost may be an alternative source of nutrient supplements. Field experiments were conducted at the Experimental Farm of Calcutta University, West Bengal, India during the wet seasons of 1997, 1998 and 1999 on flooded lowland rice. Potassium fractions in municipal waste compost and cattle manure were determined by sequential extraction and also the potassium uptake by rice to compare the effectiveness of municipal waste compost with traditional manure. Potassium was significantly bound to the organic matter in municipal waste compost. Potassium uptake by rice grain and straw increased significantly with the combined application of organics and fertilizers and it was higher in grain than in straw. Water-soluble and non-exchangeable potassium contents of municipal waste compost and cattle manure were highly correlated with the uptake of potassium by straw and grain. Exchangeable and residual potassium were also significantly correlated with the uptake of potassium by straw and grain of rice. Much higher uptake of K in rice straw and rain resulted from applying the manures in conjunction with fertilizers than when applied singly. 相似文献
48.
The sonochemical degradation of the systematically substituted azo compound 2,7-dihydroxy-1-phenylazonaphthaline-3,6-disulfonic acid was investigated using a frequency of 850 kHz and an acoustic input power of 61 W. All derivatives were degraded completely within 6h by the ultrasonic treatment. Trifluoromethyl substituted azo compounds exhibited 2-3-fold higher degradation rates in comparison to the reference hydrogen substituted azo compound (k=0.54 h(-1)). In contrast to enzymatic processes (azoreductase or laccase), the ultrasonic treatment for these ortho-, meta-, and para-substituted azo compound showed 1.5-50-fold higher degradation rates. Additionally the ultrasound treatment was characterized by shorter reaction times. As a result of the detection and identification of specific intermediates using LC-MS a reaction pathway of the sonochemical degradation of the analysed azo compound is proposed indicating the formation of cyclohexadienone and naphthalene quinone derivatives. 相似文献
49.
Determinants of Farmers’ Adoption of Improved Soil Conservation Technology in a Middle Mountain Watershed of Central Nepal 总被引:2,自引:0,他引:2
This study explores different socio-economic and institutional factors influencing the adoption of improved soil conservation technology (ISCT) on Bari land (Rainfed outward sloping terraces) in the Middle Mountain region of Central Nepal. Structured questionnaire survey and focus group discussion methods were applied to collect the necessary information from farm households. The logistic regression model predicted seven factors influencing the adoption of improved soil conservation technology in the study area including years of schooling of the household head, caste of the respondent, land holding size of the Bari land, cash crop vegetable farming, family member occupation in off farm sector, membership of the Conservation and Development Groups, and use of credit. The study showed that technology dissemination through multi-sectoral type community based local groups is a good option to enhance the adoption of improved soil conservation technology in the Middle Mountain farming systems in Nepal. Planners and policy makers should formulate appropriate policies and programs considering the farmers' interest, capacity, and limitation in promoting improved soil conservation technology for greater acceptance and adoption by the farmers. 相似文献
50.
The Singrauli region in the southeastern part of Uttar Pradesh, India is one of the most polluted industrial sites of Asia.
It encompasses 11 open cast coalmines and six thermal power stations that generate about 7,500 MW (about 10% of India’s installed
generation capacity) electricity. Thermal power plants represent the main source of pollution in this region, emitting six
million tonnes of fly-ash per annum. Fly-ash is deposited on soils over a large area surrounding thermal power plants. Fly-ashes
have high surface concentrations of several toxic elements (heavy metals) and high atmospheric mobility. Fly ash is produced
through high-temperature combustion of fossil fuel rich in ferromagnetic minerals. These contaminants can be identified using
rock-magnetic methods. Magnetic susceptibility is directly linked to the concentration of ferromagnetic minerals, primarily
high values of magnetite. In this study, magnetic susceptibility of top soil samples collected from surrounding areas of a
bituminous-coal-fired power plant were measured to identify areas of high emission levels and to chart the spatial distribution
of airborne solid particles. Sites close to the power plant have shown higher values of susceptibility that decreases with
increasing distance from the source. A significant correlation between magnetic susceptibility and heavy metal content in
soils is found. A comparison of the spatial distribution of magnetic susceptibility with heavy-metal concentrations in soil
samples suggests that magnetic measurements can be used as a rapid and inexpensive method for proxy mapping of air borne pollution
due to industrial activity. 相似文献