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Effects of Acid Rain on Competitive Releases of Cd, Cu, and Zn from Two Natural Soils and Two Contaminated Soils in Hunan, China
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.
显示更多 [+] 显示较少 [-]Extension of EU Emissions Trading Scheme to Other Sectors and Gases: Consequences for Uncertainty of Total Tradable Amount
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.
显示更多 [+] 显示较少 [-]Uncertainties of a Regional Terrestrial Biota Full Carbon Account: A Systems Analysis
2007
Nilsson, S | Shvidenko, A | Jonas, M | McCallum, R. I. | Thomson, A | Balzter, H
We discuss the background and methods for estimating uncertainty in a holistic manner in a regional terrestrial biota Full Carbon Account (FCA) using our experience in generating such an account for vast regions in northern Eurasia (at national and macroregional levels). For such an analysis, it is important to (1) provide a full account; (2) consider the relevance of a verified account, bearing in mind further transition to a certified account; (3) understand that any FCA is a fuzzy system; and (4) understand that a comprehensive assessment of uncertainties requires multiple harmonizing and combining of system constraints from results obtained by different methods. An important result of this analysis is the conclusion that only a relevant integration of inventory, process-based models, and measurements in situ generate sufficient prerequisites for a verified FCA. We show that the use of integrated methodology, at the current level of knowledge, and the system combination of available information, allow a verified FCA for large regions of the northern hemisphere to be made for current periods and for the recent past.
显示更多 [+] 显示较少 [-]Comparison of Aeration Status Measurements by Clark Sensor (DO) and ODR-Meter during Azolla caroliniana Willd. Growth in the Presence of Cd(II) and Hg(II)
2007
Bennicelli, R. P. | Stępniewska, Z. | Banach, K. | Banach, A. M. | Szafranek, A.
The aim of this study was examination possibility of Azolla caroliniana Willd. to aerate its medium enriched with Cd(II) and Hg(II) and comparison of DO and ODR methods in measurement aeration status of solutions. Azolla system has been chosen to verify the validity of the measuring ODR method in water solution. Water aeration measurements, one of important environmental tests, are performed most often by measurement of dissolved oxygen with oxygen sensors. Other similar method called oxygen diffusion rate is generally used in different porous materials such as soil. Our first objective was to check if these both methods are comparable and may be use exchangeable in water solution. The both types of measurements were performed in medium saturated at different oxygen concentrations. The linear relationship and high correlation (R = 0.89) were found between values of ODR and DO. The object of the second part of our studies was A. caroliniana Willd. (Azollaceae), a floating water fern living in symbiosis with cyanobacterium Anabaena azollae Strasb. (Nostoceae) that fixes atmospheric nitrogen. Azolla plants are used for centuries as a nitrogen biofertilizer. The second aim of our work was to find out, if the fern reduces or increases oxygen concentration in water. The ODR method was used to determine the aeration status of the nutrient solution. During 12 days of the experiment at laboratory conditions, an active role of A. caroliniana in aeration of the nutrient solution containing Cd(II) and Hg(II) was stated.
显示更多 [+] 显示较少 [-]Effects of Changed Soil Conditions on the Mobility of Trace Metals in Moderately Contaminated Urban Soils
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.
显示更多 [+] 显示较少 [-]Water Quality Retrievals from High Resolution Ikonos Multispectral Imagery: A Case Study in Istanbul, Turkey
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.
显示更多 [+] 显示较少 [-]Macrophyte Sorption and Bioconcentration of Elements in a Pilot Constructed Wetland for Flue Gas Desulfurization Wastewater Treatment
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.
显示更多 [+] 显示较少 [-]Bioremediation of Oil Sludge in Shengli Oilfield
2007
De-qing, Shi | Jian, Zhang | Zhao-long, Gui | Jian, Dong | Tian-li, Wang | Murygina, Valentina | Kalyuzhnyi, Sergey
Large quantity of dehydrated oil sludge, generated in the disposal process of oil-containing sewage in Shengli oilfield, needs to be rendered harmless to human and to the environment. Bioremediation has been accepted as an important method for the treatment of oil sludge by employing indigenous or extraneous microbial flora. The bioremediation of a dehydrated oil sludge of 960 m³ in volume was carried out in a prepared bed in Binyi oil-containing sewage disposal station, Shengli oil fields, China. Four different treatments were made to study the impact of certain process parameters on the bioremediation efficiency. Of the oil contaminants, 52.75% was degraded within 160 days when treated in a greenhouse, while the oil contaminations decreased by only 15.46% in the untreated sludge. The variations of the physical and chemical properties of oil sludge, the amount and the functional diversity of microorganisms in sludge were characterized. The results indicated that the water-holding capacity of oil sludge, the amount and the metabolism functional diversity of microorganisms in sludge in the three treatments increased markedly compared with the control.
显示更多 [+] 显示较少 [-]A High CO Episode of Long-Range Transport Detected by MOPITT
2007
Zhao, C. | Peng, L. | Tie, X. | Lin, Y. | Li, C. | Zheng, X. | Fang, Y.
Recent developments in satellite remote sensing technologies resulted in the ability to observe major pollution events such as dust and smoke around the world on a daily basis. Satellite imagery can sometimes detect long-range transport episodes. In this paper, a high CO episode at remote GAW station, Mt. Waliguan, detected by MOPITT CO dataset during the end of April 2002, is described. CO concentrations above 600 hPa almost doubled on 27 April and CMDL surface sample measurements also observed this significant CO enhancement. Using NCEP data, satellite fire products data and backward trajectory model we suggest that this high CO episode of 27 April is not a local pollution event, but that it is due to long-range transport from active biomass burning and biofuel burning areas located in the border areas of Pakistan and India. The trajectory cluster analysis shows that the origins of 5-day backward trajectories, for air masses reaching Mt. Waliguan station, at all altitudes, mainly overlap with the fire spot locations detected by TRMM data and biofuel burning in India.
显示更多 [+] 显示较少 [-]Measurement Uncertainty of Sulphur and Nitrogen Containing Inorganic Compounds By 1-Stage and 2-Stage Filter-pack Methods
2007
Karlsson, Vuokko | Pyy, Katriina | Saari, Helena
The sampling and analysis properties of 1-stage and 2-stage filter-pack methods were studied in detail in monitoring of sulphur and nitrogen containing inorganic gases and particles (sulphur dioxide, sulphate, sum of nitric acid and nitrate and total ammonium). The limit of detection and the limit of quantitation for 24-h samples were estimated using the results of a short-term field experiment completed with available data from long-term monitoring and internal quality assurance. Furthermore, the combined expanded measurement uncertainty including sampling and analysis (Uₜₒₜ) was estimated for filter-pack methods in order to give a tool for distinguishing long-term trends in air quality from the measurement variability. Uₜₒₜ was found to be very near the analytical uncertainty when measuring higher air concentration levels, being ± 4.0% for sulphur concentrations > 1.0 μg m⁻³, ± 3.0% for sulphate concentrations > 0.5 μg m⁻³, ± 3.5% for the sum of nitrate and nitric acid concentrations > 0.3 μg m⁻³ and ± 4.5% for total ammonium concentrations > 0.8 μg m⁻³. At the lower air concentration range Uₜₒₜ increases significantly due to the field blank values. The precision of the 24-h filter-pack sample results expressed by means of modified median absolute difference (M.MAD) and coefficient of variance (CoV) gave 8.3% for sulphur dioxide and 5.4% for particulate sulphate. For the sum of gaseous nitric acid and particulate nitrate the CoV was 5.5% and for total ammonium 4.3%. In addition the suitability of the 24-h filter-pack methods in weekly sampling was proved.
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