Уточнить поиск
Результаты 161-170 из 449
Metalliferous Constituents of Rhizosphere Soils Contaminated by Zn-Pb Mining in Southern Poland Полный текст
2007
Cabala, J. | Teper, L.
Industrial soils near Zn-Pb mines and metallurgical plants in the vicinity of Olkusz (southern Poland) are exposed to high environmental stress related to heavy metal pollution (Zn, Pb, Cd, Mn, Fe, Tl and As) from waste disposal sites and primary ores. X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectrometry analyses (EDS) and Atomic Absorption Spectroscopy (AAS) were used to analyse rhizosphere soil samples from the area. The mineral composition of the rhizosphere soils was determined. Carbonates of lead, cadmium and zinc, arsenic-lead sulphosalts and other minerals occurring on the root epiderm are described. Mineral aggregates of secondary origin include polymineralic spherules containing high concentrations of Zn (up to 2.3%), Pb (up to 0.7%), Fe (up to 23%), Cd (up to 427 mg kg-¹) and Tl (up to 139 mg kg-¹). Processes on the rhizoplane, and in the zone where plant-root exudation solutions are active, promote the crystallization of metalliferous minerals. ESEM is recommended as an efficient method for examining alteration occurring in the rhizosphere environment.
Показать больше [+] Меньше [-]Emission of Volatile Organic Compounds during Composting of Poultry Litter Полный текст
2007
Turan, N. G. | Akdemir, A. | Ergun, O. N.
The objective of this study was to identify and quantify volatile organic compounds (VOCs) produced during composting of poultry litter. The VOCs produced from in-vessel composting with a controlled aeration system were tested using the F-ITR method by VOC analyzer. Alkanes and alkylated benzenes were emitted in the highest amounts from poultry litter, while aldehydes, terpenes, ketones were emitted in much lesser amounts. Studies showed that VOCs generation was the greatest early during the composting process and greatly reduced thereafter. Composting temperatures were found to affect VOCs. All VOCs were least with the high temperatures generated during composting.
Показать больше [+] Меньше [-]Influence of Agricultural Land Use and Management on the Contents of Polycyclic Aromatic Hydrocarbons in Selected Silty Soils Полный текст
2007
Oleszczuk, Patryk | Pranagal, Jacek
The aim of the present study was the influence of various methods of long-term soil utilisation on the content of polycyclic aromatic hydrocarbons (PAH) in selected silty soils. Four soils were selected for the present studies, i.e.: Eutric Fluvisol originating from silty formations, Haplic Phaeozem developed from loess, Haplic Luvisol (non-uniform) developed from silt, Haplic Luvisol developed from loess. Five study sites were chosen, i.e.: apple orchards, hop gardens, fields, grasslands and natural woodland ecosystems. Samples were collected from the depth of 0-10 cm. In the samples the content of 16 PAHs was determined by means of the HPLC-UV method. The total PAHs content was at a low level. Depending on the soil and object type, the total PAHs content ranged from 72.5 to 764.0 μg·kg-¹. The pollutant level determined together with composition of individual PAHs suggested a limited anthropogenic influence relating mainly to pyrolytic processes. The total PAH content as well as the content of individual PAHs depended on agricultural land use and management. It has been shown that PAH level was influenced by environmental conditions specific for a given type of land use. In the soils in which organic carbon content differed only slightly among locations, a higher influence of the soil utilisation method on the content of individual PAHs was observed.
Показать больше [+] Меньше [-]Effects of Acid Rain on Competitive Releases of Cd, Cu, and Zn from Two Natural Soils and Two Contaminated Soils in Hunan, China Полный текст
2007
Liao, Bohan | Guo, Zhaohui | Zeng, Qingru | Probst, Anne | Probst, Jean-Luc
Leaching experiments of rebuilt soil columns with two simulated acid rain solutions (pH 4.6-3.8) were conducted for two natural soils and two artificial contaminated soils from Hunan, south-central China, to study effects of acid rain on competitive releases of soil Cd, Cu, and Zn. Distilled water was used in comparison. The results showed that the total releases were Zn>Cu>Cd for the natural soils and Cd>Zn[double greater-than sign]Cu for the contaminated soils, which reflected sensitivity of these metals to acid rain. Leached with different acid rain, about 26-76% of external Cd and 11-68% external Zn were released, but more than 99% of external Cu was adsorbed by the soils, and therefore Cu had a different sorption and desorption pattern from Cd and Zn. Metal releases were obviously correlated with releases of TOC in the leachates, which could be described as an exponential equation. Compared with the natural soils, acid rain not only led to changes in total metal contents, but also in metal fraction distributions in the contaminated soils. More acidified soils had a lower sorption capacity to metals, mostly related to soil properties such as pH, organic matter, soil particles, adsorbed SO₄ ²-, exchangeable Al³⁺ and H⁺, and contents of Fe₂O₃ and Al₂O₃.
Показать больше [+] Меньше [-]Extension of EU Emissions Trading Scheme to Other Sectors and Gases: Consequences for Uncertainty of Total Tradable Amount Полный текст
2007
Monni, S | Syri, S | Pipatti, R | Savolainen, I
Emissions trading in the European Union (EU), covering the least uncertain emission sources of greenhouse gas emission inventories (CO₂ from combustion and selected industrial processes in large installations), began in 2005. During the first commitment period of the Kyoto Protocol (2008-2012), the emissions trading between Parties to the Protocol will cover all greenhouse gases (CO₂, CH₄, N₂O, HFCs, PFCs, and SF₆) and sectors (energy, industry, agriculture, waste, and selected land-use activities) included in the Protocol. In this paper, we estimate the uncertainties in different emissions trading schemes based on uncertainties in corresponding inventories. According to the results, uncertainty in emissions from the EU15 and the EU25 included in the first phase of the EU emissions trading scheme (2005-2007) is ±3% (at 95% confidence interval relative to the mean value). If the trading were extended to CH₄ and N₂O, in addition to CO₂, but no new emissions sectors were included, the tradable amount of emissions would increase by only 2% and the uncertainty in the emissions would range from -4 to +8%. Finally, uncertainty in emissions included in emissions trading under the Kyoto Protocol was estimated to vary from -6 to +21%. Inclusion of removals from forest-related activities under the Kyoto Protocol did not notably affect uncertainty, as the volume of these removals is estimated to be small.
Показать больше [+] Меньше [-]Modeling Study of Long-Range Transport of SO2, NOx and O3 Over Northeast Asia in March 2002 Полный текст
2007
Han, Z. | Ueda, H. | Hozumi, Y. | Sakurai, T.
The characteristics of transport and transformation of SO₂, NOx and O₃ in northeast Asia have been investigated by using a comprehensive regional air quality model (RAQM) driven by a meteorological model MM5. A study period of 1-15 March 2002 has been selected due to the availability of intense observation of chemical species for both ground and upper levels. Model results have been compared against observational data to provide insights into the strength and weakness of the model's ability and the evolutionary features of chemical species. Validation shows a good skill of this model system in reproducing most of the key features in long-range transport, but apparent bias still remains due to a series of uncertainties from either emission estimates, prescribed parameters, or inherent model limitations. In general, this model shows a better skill for SO₂ and O₃ than for NOx. Large discrepancy occurs between the observed and calculated NOx concentration at higher levels, with the model results being much lower. A series of sensitivity tests have been conducted to investigate the potential affecting factors and it is found that the inaccuracy or incompleteness in currently used emission inventories could be a most likely cause for such discrepancy. Long-range transport from Asian continent to the western Pacific is pronounced in springtime. Substantially high concentrations of SO₂ and NOx in or above the boundary layer (0.5~3.0 km) over the Yellow Sea suggest an important pathway for long-range transport in northeast Asia.
Показать больше [+] Меньше [-]A Synoptic Climatological Approach to Assess Climatic Impact on Air Quality in South-central Canada. Part II: Future Estimates Полный текст
2007
Cheng, Chad Shouquan | Campbell, Monica | Li, Qian | Li, Guilong | Auld, H. | Day, Nancy | Pengelly, David | Gingrich, Sarah | Ye, Zhiming
Using within-weather-group air pollution prediction models developed in Part I of this research, this study estimates future air pollution levels for a variety of pollutants (specifically, carbon monoxide – CO, nitrogen dioxide – NO₂, ozone – O₃, sulphur dioxide – SO₂, and suspended particles – SP) under future climate scenarios for four cities in south-central Canada. A statistical downscaling method was used to downscale five general circulation model (GCM) scenarios to selected weather stations. Downscaled GCM scenarios were used to compare respective characteristics of the weather groups developed in Part I; discriminant function analysis was used to allocate future days from two windows of time (2040–2059 and 2070–2089) into one of four weather groups. In Part I, the four weather groups were characterised as hot, cold, air pollution-related, and other (defined as relatively good air quality and comfortable weather conditions). In estimating future daily air pollution concentrations, three future pollutant emission scenarios were considered: Scenario I – emissions decreasing 20% by 2050, Scenario II – future emissions remaining at the same level as at the end of the twentieth century, and Scenario III – emissions increasing 20% by 2050. The results showed that, due to increased temperatures, the average annual number of days with high O₃ levels in the four selected cities could increase by more than 40–100% by the 2050s and 70–200% by the 2080s (from the current areal average of 8 days) under the three pollutant emission scenarios. The corresponding number of low O₃ days could decrease by 4–10% and 5–15% (from the current areal average of 312 days). For the rest of the pollutants, future air pollution levels will depend on future pollutant emission levels. Under emission Scenarios II and III, the average annual number of high pollution days could increase 20–40% and 80–180%, respectively, by the middle and late part of this century. In contrast, under Scenario I, the average annual number of high pollution days could decrease by 10–65%.
Показать больше [+] Меньше [-]Effects of Changed Soil Conditions on the Mobility of Trace Metals in Moderately Contaminated Urban Soils Полный текст
2007
Linde, Mats | Gustafsson, Jon Petter
Changes in the soil chemical environment can be expected to increase the leaching of trace metals bound in soils. In this study the mobility of trace metals was monitored in a column experiment for two contaminated urban soils. Four different treatments were used (i.e. rain, acid rain, salt and bark). Leachates were analysed for pH, dissolved organic carbon (DOC) and for seven trace metals (cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn)). The salt treatment produced the lowest pH values (between 5 and 6) in the effluent whereas the DOC concentration was largest in the bark treatment (40-140 mg L-¹) and smallest in the salt and acid treatments (7-40 mg L-¹). Cadmium, Ni and Zn were mainly mobilised in the salt treatment, whereas the bark treatments produced the highest concentrations of Cu and Pb. The concentrations of Cu, Cr, and Hg were strongly correlated with DOC (r ² = 0.90, 0.91 and 0.96, respectively). A multi-surface geochemical model (SHM-DLM) produced values for metal dissolution that were usually of the correct magnitude. For Pb, however, the model was not successful indicating that the retention of this metal was stronger than assumed in the model. For all metals, the SHM-DLM model predicted that soil organic matter was the most important sorbent, although for Pb and Cr(III) ferrihydrite was also important and accounted for between 15 and 50% of the binding. The results confirm the central role of DOC for the mobilization of Cu, Cr, Hg and Pb in contaminated soils.
Показать больше [+] Меньше [-]Water Quality Retrievals from High Resolution Ikonos Multispectral Imagery: A Case Study in Istanbul, Turkey Полный текст
2007
Ekercin, Semih
This paper presents an application of high resolution satellite remote sensing data for mapping water quality in the Goldon Horn, Istanbul. It is an applied research emphasizing the present water quality conditions in this region for water quality parameters; secchi disc depth (SDD), chlorophyl-a (chl-a) and total suspended sediment (TSS) concentration. The study also examines the retrievals of these parameters through high resolution IKONOS multispectral data supported by in situ measurements. Image processing procedure involving radiometric correction is carried out for conversion from digital numbers (DNs) to spectral radiance to correlate water quality parameters and satellite data by using multiple regression technique. The retrieved and verified results show that the measured and estimated values of water quality parameters in good agreement (R ² > 0.97). The spatial distribution maps are developed by using multiple regression algorithm belonging to water quality parameters. These maps present apparent spatial variations of selected parameters and inform the decision makers of water quality variations in a large water region in the Istanbul metropolitan area.
Показать больше [+] Меньше [-]Macrophyte Sorption and Bioconcentration of Elements in a Pilot Constructed Wetland for Flue Gas Desulfurization Wastewater Treatment Полный текст
2007
Sundberg-Jones, Sarah E. | Hassan, El-Sayed M.
The sorption and bioconcentration of Hg, Se, and As were measured in Schoenoplectus californicus and Typha angustifolia in a pilot constructed wetland receiving wastewater inflows containing these elements at potentially hazardous levels. Results indicated that these species bioconcentrated Hg, Se, and As at factors of up to 1,911, 10,981, and 4,927, respectively. Plant tissue concentrations decreased as Hg, Se, and As were translocated from the roots to the aerial portions of the plant. Greatest element concentrations in S. californicus were found in roots, indicating that an exclusion mechanism may be responsible for element tolerance by this plant species. Greater root:shoot transfer of Hg, Se, and As was observed with T. angustifolia than with S. californicus, suggesting that element tolerance was more likely due to an internal detoxification mechanism. To completely assess ecological risks associated with the use of constructed wetlands, contaminant bioavailability for plant uptake, translocation, and bioconcentration must be considered.
Показать больше [+] Меньше [-]