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النتائج 521 - 530 من 783
Evaluation of Greenwaste Mulch to Control Runoff Quality from Landfill Sites During Frequent Storms النص الكامل
2009
Brodie, I. M. | Misra, R. K.
This paper describes a preliminary evaluation of two types of greenwaste (fresh and aged) used as a mulch layer to control runoff from disturbed landfill areas. Fresh greenwaste refers to woody and herbaceous garden waste that has been recently collected, chopped and shredded. Aged greenwaste is greenwaste which has been stockpiled for 18 months. We used rainfall simulator tests to investigate two aspects: (1) the performance of greenwaste mulch in reducing runoff during designed storm events with a high frequency of occurrence and (2) the release of pollutants via runoff as total suspended solids (TSS) and total organic carbon (TOC) during rain. Rainfall of <5-year average recurrence interval (ARI) was generally applied, consistent with stormwater compliance requirements for many Australian landfills. TOC released from fresh greenwaste material was higher in concentration than from aged greenwaste. However, when used as a 10-cm-deep mulch layer, fresh greenwaste was able to completely prevent runoff, even when tested under rainfalls of up to 50-year ARI duration. An equivalent mulch layer of aged greenwaste was also effective in reducing runoff volume and TSS concentration compared with the bare soil during a 3.5-year ARI rainfall, but mean TOC concentration was higher. Based on these preliminary results, fresh greenwaste mulching of bare soils is an attractive option to control runoff and erosion from areas subject to intermittent landfill operations and worthy of further investigations.
اظهر المزيد [+] اقل [-]Metal Accumulation by Woody Species on Contaminated Sites in the North of France النص الكامل
2009
Migeon, Aude | Richaud, Pierre | Guinet, Frédéric | Chalot, Michel | Blaudez, Damien
Metal Accumulation by Woody Species on Contaminated Sites in the North of France النص الكامل
2009
Migeon, Aude | Richaud, Pierre | Guinet, Frédéric | Chalot, Michel | Blaudez, Damien
Metal accumulation was investigated in a range of woody species that were planted on Cd-, Zn- and Pb- polluted sites in North of France. The study is unique in that we directly compare a large number of woody species (25). The highest accumulation of Zn and Cd was found in the Salicaceae family members with up to 950 mg Zn kg⁻¹ dry weight (DW) and 44 mg Cd kg⁻¹ DW in leaves of Populus tremula × Populus tremuloides. Zn content was positively correlated with Cd content, both in leaves and stems. Pb concentration was generally low and was species-independent. Oak and birch species accumulated more Mn as compared to other woody species. A seasonal variation in metal accumulation could be found. Although soil compositions and metal bioavailabilities differed amongst the experimental sites chosen in this study, variation of metal concentrations within a given species was small. High bioconcentration factors for poplar and willow suggested the high potential of these species over other woody species for metal accumulation. Taken together, these data suggest that poplar and willow species are good candidates for phytoremediation programmes.
اظهر المزيد [+] اقل [-]Metal Accumulation by Woody Species on Contaminated Sites in the North of France النص الكامل
2009
Migeon, Aude | Richaud, Pierre | Guinet, Frédéric | Chalot, Michel | Blaudez, Damien | Interactions Arbres-Microorganismes (IAM) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | CEA Cadarache ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
International audience
اظهر المزيد [+] اقل [-]Monitoring BTEX and Aldehydes in Car Exhaust from a Gasoline Engine During the Use of Different Chemical Cleaners by Solid Phase Microextraction-Gas Chromatography النص الكامل
2009
Niri, Vadoud H. | Mathers, James B. | Musteata, Marcel F. | Lem, Stan | Pawliszyn, Janusz
All commercial gasoline fuels build up deposits on the spark plugs, injectors, oxygen sensors, catalytic converter, and inside the combustion chamber, which will lower the engine's performance and increase air pollution. As a result, fuel-based detergents have been developed to prevent and remove unwanted deposits. Unfortunately, many of the detergents use high amounts of aromatic solvents, which result in a greater risk of exposure to aromatic compounds like benzene. In this study, car exhaust was analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX), as well as formaldehyde and acetaldehyde during engine cleaning service using different chemical cleaners. A special device was designed for sampling from car exhaust using solid phase microextraction. The extracted compounds were analyzed using a gas chromatograph with flame ionization detector. The cleaning products were rated with regard to the amount of pollutants produced during the cleaning service.
اظهر المزيد [+] اقل [-]Bioremediation of Lindane Contaminated Soil by Pleurotus ostreatus in Non Sterile Conditions Using Multilevel Factorial Design النص الكامل
2009
Rigas, F. | Papadopoulou, K. | Philippoussis, A. | Papadopoulou, M. | Chatzipavlidis, J.
A commercial strain of the fungus Pleurotus ostreatus was used to mediate the degradation of lindane, by landfarming technology during a 4 weeks statistical experiment. The Multilevel Factorial Design was used with two design factors, namely, straw content X ₁ (%) and lindane content X ₂ (ppm). The optimization parameters (responses) investigated were: biodegradation rate Y ₁ (μg d⁻¹), biomass growth rate Y ₂ (mg d⁻¹), biodegradation/biomass Y ₃ (μg mg⁻¹), total organic carbon Y ₄ (%), total organic nitrogen Y ₅ (%) and total organic carbon/total organic nitrogen Y ₆. The optima of the adequate models obtained for the period of 2 and 4-weeks were found. An overall kinetic study, conducted in this work with the aid of experimental design, determined the optimum (maximum) specific lindane degradation rate to be 0.16 g kg⁻¹ month⁻¹.
اظهر المزيد [+] اقل [-]A Small-Scale Sulfate-Reducing Bioreactor for Manganese Removal from a Synthetic Mine Drainage النص الكامل
2009
Edwards, J. D. | Barton, C D | Karathanasis, A. D.
This research evaluated the efficiency of a mesocosm scale bioreactor to remove Mn from a synthetic mine drainage in the presence of selected organic and inorganic substrate combinations that could enhance sulfate reduction and induce Mn sulfide precipitation. The mine drainage tested was slightly acidic (pH 6.2) and had average Mn and SO₄ concentrations of 90 and 1,500 mg/L, respectively. The substrates used were creek sediment amended with either wood mulch or a wood mulch and biosolid mixture. Greater than 90% of Mn and 70% of sulfate was removed over a 65-day test period. The results suggested multiple Mn removal mechanisms including sorption, complexation, and Mn sulfide, Mn oxide, and/or Mn carbonate precipitation.
اظهر المزيد [+] اقل [-]The Effects of Lithology on Water Pollution: Natural Radioactivity and Trace Elements in Water Resources of Eskisehir Region (Turkey) النص الكامل
2009
Yuce, Galip | Ugurluoglu, Didem | Dilaver, Alime T. | Eser, Turgay | Sayin, Mesut | Donmez, Mert | Ozcelik, Sakir | Aydin, Funda
The high radioactivity and trace elements in drinking water are common concerns for human health. The aim of this study was to investigate the eligibility of groundwater for drinking purpose in terms of both radioactivity and trace element contents in Eskisehir Region (Turkey). The study area is located in a highly populated residential area where water supply is mostly met from groundwater. The area is about 20,000 km², where igneous, metamorphic, and sedimentary rocks are exposed. The 209 water samples collected from 84 water resources (including thermal waters) were analyzed with respect to major ions, trace elements, and radioactivity (gross alpha and gross beta) during both in wet and dry seasons. Based on the analysis results, trace elements in 49 samples of 84 water resources were over the limits of Code TS 266 1997 (Turkish Drinking Water Standards) and WHO 1993 standards. Particularly, Fe, Mn, Al, As, Ba, Zn, Cr, Cu, and B ion concentrations exceeded the limits. The gross alpha values in 18 locations and gross beta values in three locations also exceeded the limits of aforementioned standards in terms of radioactivity (gross alpha = 0.1 Bq L⁻¹; gross beta = 1 Bq L⁻¹). Furthermore, water radioactivity levels were close to the allowable limits in 33 water resources. The obtained results explicitly indicate that there is a strong relationship between the higher radioactivity-trace element contents and geochemical composition of rocks, which controls the radioactivity and trace element concentrations present in the aquifer.
اظهر المزيد [+] اقل [-]Aerosol Inorganic Ions in a Semiarid Region on the Southeastern Spanish Mediterranean Coast النص الكامل
2009
Nicolás, J. F. | Galindo, N. | Yubero, E. | Pastor, C. | Esclapez, R. | Crespo, J.
PM2.5 and PM10 samples were collected in the urban atmosphere of Elche (southeastern Spain) between December 2004 and November 2005. The samples were analyzed for mass and water-soluble inorganic ions (Na⁺, [graphic removed] , K⁺, Ca²⁺, Mg²⁺, Cl⁻, [graphic removed] and [graphic removed] ) with the aim of investigating the influence of the climatic and geographic features of a coastal semiarid area on the contribution of these species to PM levels. Secondary inorganic ions ( [graphic removed] , [graphic removed] , [graphic removed] ) were the major components in the fine fraction (PM2.5), accounting for 40% of the total mass. The relationship between non-marine [graphic removed] and [graphic removed] indicated that fine sulfate particles were completely neutralized by ammonium. In the coarse fraction (PM10-2.5), nitrate (as NaNO₃ and Ca(NO₃)₂), together with crustal (CaCO₃) and marine species (NaCl) accounted for almost 50% of the total mass. Fine sulfate and coarse nitrate showed summer maximums. In contrast, the concentrations of fine [graphic removed] were lowest in the warm period. Ammonium presented both winter and summer maximums. The levels of marine ions, except for coarse Cl⁻, were highest in summer when the dominant wind flow is from the sea. No significant seasonal variations were observed for coarse Ca²⁺ and [graphic removed] . The concentrations of all inorganic ions increased during Saharan dust events, in particular, fine [graphic removed] and [graphic removed] and coarse [graphic removed] . Coarse calcium was proved not to be a good tracer for this type of episode in our region since the average levels of this cation are elevated and the relative increase in its concentrations during African events was not as high as expected.
اظهر المزيد [+] اقل [-]SO₂ and NOx Emissions from Kuwait Power Stations in Years 2001 and 2004 and Evaluation of the Impact of These Emissions on Air Quality Using Industrial Sources Complex Short-Term (ISCST) Model النص الكامل
2009
Al-Azmi, Bader N. | Nassehi, V. | Khan, A. R.
Comprehensive emission inventories for 2001 and 2004 for Kuwait's main power stations located at Al-Doha and Al-Subyia have been prepared. These inventories are inserted, in conjunction with meteorological data, into the Source Complex model for Short Term Dispersion (ISCST4.5) to predict ambient ground level concentrations of sulphur dioxide (SO₂) and nitrogen oxides (NOx) at selected receptors for years 2001 and 2004. The comparison of the results obtained for these 2 years show the influence of increase in emission rates due to urban and industrial growth. For model validation, computed results are compared with the measured daily average values of SO₂ and NOx collected at a fixed Kuwait Environment Protection Agency air quality monitoring station located at the roof of polyclinic in Rabia. Individual contributions of each power station to the highest predicted values are assessed. The five highest hourly, daily and annual ground level concentration values under prevailing meteorological conditions are compared for 2001 and 2004. It is found that the hourly mean concentrations are strongly influenced by the prevailing meteorological conditions. The effect of meteorological conditions has not been that dominant for the daily and annual mean values and the predicted values for 2004 are higher than 2001, simply corresponding to a high emission rates, especially in summer months. Top 50 daily average values of SO₂ show a slope of 0.806 for 2001 which means that the model predictions are 20% less than the observed levels. However, the predicted slope of SO₂ for 2004 is 0.96 and the model predictions are in very close agreement with the observed data.
اظهر المزيد [+] اقل [-]Inorganic Pollutants in Wet Atmospheric Deposition and the Trajectories of Their Possible Transport النص الكامل
2009
Vach, Marek | Skřivan, Petr | Rohovec, Jan | Fišák, Jaroslav | Kubínová, Petra | Burian, Miloš
This work is concerned with analysis of the transport trajectories and identification of the probable emission sources of a set of chemical elements monitored in samples of atmospheric precipitation collected in the area of Central Bohemia, Czech Republic. This is based on evaluation of the significance of transport trajectories obtained using the HYSPLIT model for specific periods of duration of the sampled precipitation episodes in dependence on the values of the corrected concentrations of the monitored elements in the individual samples. The proposed method of correction of the measured concentrations of the elements is concerned with elimination of meteorological effects that are unspecific from with respect to the direction of the transport trajectories. The results for the group of elements with higher concentration levels in the sampled precipitation agree with the assumptions on their probable most important sources. The common main source of Na, Mg and Ca is marine aerosol, while K, P and Mn are probably of biogenic origin. The common main sources of Al and Fe--probably terrigenic dust--also correspond to the assumptions. Sulfur does not exhibit a significant predominant direction to the sampling site. Zinc, Cd, Cu and also Si are transported to the greatest degree from the north-westerly direction, indicating the probable effect of large energy-production sources in the area under the Krušné Mountains in the CR or the effect of traffic in the Capital City of Prague. The predominant direction of dispersion of Pb and As is a north-easterly to easterly direction of transport.
اظهر المزيد [+] اقل [-]Remediation of Copper and Cadmium in Contaminated Soils using Compost with Inorganic Amendments النص الكامل
2009
Gadepalle, Vishnu Priya | Ouki, Sabeha K. | Hutchings, Tony
Compost enriched with inorganic amendments has been evaluated in laboratory-based experiments for its effectiveness to immobilise heavy metals in contaminated soils. This paper reports the results pertaining to copper (Cu) and cadmium (Cd) only. The inorganic amendments used were naturally occurring zeolite-Clinoptilolite and synthetic iron oxide (Fe₂O₃). A series of experiments have been performed on the amended soils and the results demonstrated that a combination of compost/iron oxide was effective in reducing the uptake of Cu in rye grass (Lolium perenne L.) whereas compost/iron oxide as well as compost/zeolite mixture was effective for reducing Cd uptake. The amended compost performed better in re-vegetating contaminated soil compared to compost or amendments alone. The sequential extraction of the control sample showed that major fraction of both Cu and Cd were associated with organic fraction indicating that the metals might be available to plants under oxidising conditions of soil. The percentage of Cu in the control sample associated with different fractions was in the following order: Organic > Residual > Reducible > Exchangeable fraction whereas for Cd it was: Organic > Reducible > Residual > Exchangeable. The sequential extraction of amended soils showed that exchangeable Cu decreased by 50% to 92% compared to the control. An increase in residual fraction of Cd (up to 40%) was observed in the amended soils. It was concluded that zeolite and/or iron oxide enriched compost can be used effectively for immobilising Cu and Cd in contaminated soils. The effect of amended compost on other metals should be taken into consideration for real field applicaitons.
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