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Aerosol Inorganic Ions in a Semiarid Region on the Southeastern Spanish Mediterranean Coast Texto completo
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.
Mostrar más [+] Menos [-]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 Texto completo
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.
Mostrar más [+] Menos [-]Inorganic Pollutants in Wet Atmospheric Deposition and the Trajectories of Their Possible Transport Texto completo
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.
Mostrar más [+] Menos [-]Remediation of Copper and Cadmium in Contaminated Soils using Compost with Inorganic Amendments Texto completo
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.
Mostrar más [+] Menos [-]Ash Leaching of Forest Species Treated with Phosphate Fire Retardants Texto completo
2009
Liodakis, Stylianos | Tsoukala, Magdalini
The chemical, mineralogical, and leaching behavior of three dominant Greek forest species ashes (Pinus halepensis, Pistacia lentiscus, and Olea europaea), before and after treating forest species with diammonium phosphate (DAP) 5% and 10% weight to weight, have been studied using a new five-step shake leaching method at pH = 6. For the analysis of ashes (prior and after leaching) and leachants, the following analytical techniques were used: atomic absorption spectroscopy, X-ray diffraction, and scanning electron microscopy with energy dispersive X-ray fluorescence analysis. The presence of DAP obstructs the extraction process of some metal ions (i.e., Na, K) contained in ashes by converting the soluble carbonate salts to the less soluble phosphates (i.e., Na₂CO₃ [rightward arrow] Na₃PO₄). On the contrary, DAP enhances the mobility of some other metals (i.e., Ca) by forming more soluble compounds [i.e., CaCO₃ [rightward arrow] Ca₃(PO₄)₂]. In addition, the presence of DAP lowers the pH of leachates, causing dissolution of some toxic elements (i.e., Mn, Pb, Zn). Unexpectedly, DAP prevents the leachability of Cr from ash. The above study concerns the environmental effects (soil and ground and underground water streams) caused by the use of chemical retardants on forest fires.
Mostrar más [+] Menos [-]Quantitative Comparison of Heavy Metals and As Accumulation in Agricultural and Forest Soils near Bowling Green, Ohio Texto completo
2009
Neupane, Ghanashyam | Roberts, Sheila J.
Soil samples from agricultural and adjacent forest soils in Northwest Ohio were collected and analyzed for As, Cr, Cu, Ni, Pb, and Zn. pH, Eh, electrical conductivity, and moisture content were also measured. Selected samples were also evaluated for grain size and X-rayed to identify clay minerals. In this region, soils contain a large proportion of fines (~32% clay and ~37% silt) with illite, dickite, and chlorite as the main clay minerals. Surface soils in the arable land are slightly acidic (pH ~5.6) while forest soils are near-neutral to slightly basic. All soils become more basic with depth. Soil Eh and electrical conductivity range from 300 to 450 mV and 100 to 375 μS, respectively. In the soil profiles, between 0 and 50 cm depth, As increases from 4.6 to 11 mg/kg, Cr increases from19 to 23 mg/kg and Ni increases 21 to 29 mg/kg. In contrast, Cu decreases from 23 to 17 mg/kg and Pb decreases from17 to 10 mg/kg. Surface enrichment of Cu and Pb can be the result of aerosol deposition, while the downward increase in As, Cr and Ni is related to pedogenic variation. The average concentration of Zn in the samples is 64 mg/kg and does not change with land-use or depth. With the exception of As, the concentration of metals in the agricultural soil is not significantly different from the concentration in forest soil. The concentration of As in the near-surface arable soil (5.6 mg/kg) is significantly different from the concentration of As in the near-surface forest soil (4.3 mg/kg). In both cases, deeper soils have similar As contents. The relative enrichment of As in the surface arable soil could indicate input from herbicides or pesticides. The upward increase in electrical conductivity is interpreted to show that the exchangeable fraction of each metal is higher in the surface soils. However, the near neutral pH and organic, clay-rich soils may limit the mobility. The concentration of these heavy metals and As in the soils are much lower than the limits set by the United States Environmental Protection Agency.
Mostrar más [+] Menos [-]Silicon Effects on Metal Tolerance and Structural Changes in Maize (Zea mays L.) Grown on a Cadmium and Zinc Enriched Soil Texto completo
2009
da Cunha, Karina Patrícia Vieira | do Nascimento, Clístenes Williams Araújo
Silicon presents a close relationship with the amelioration of heavy metals phytotoxicity. However, mechanisms of Si-mediated alleviation of metal stress remains poorly understood. This work aimed at studying the relationship between the accumulation of Si, Cd, and Zn and the tolerance and structural alterations displayed by maize plants grown on a Cd and Zn enriched soil treated with doses of Si (0, 50, 100, 150, and 200mg kg⁻¹) as calcium silicate (CaSiO₃). The results showed that the maize plants treated with Si presented not only biomass increasing but also higher metal accumulation. Significant structural alterations on xylem diameter, mesophyll and epidermis thickness, and transversal area occupied by collenchyma and midvein were also observed as a result of Si application. The deposition of silica in the endodermis and pericycle of roots seems to play an important role on the maize tolerance to Cd and Zn stress.
Mostrar más [+] Menos [-]Influence of Common Reed (Phragmites australis) on CH₄ Production and Transport in Wetlands: Results from Single-Plant Laboratory Experiments Texto completo
2009
Duan, Xiaonan | Wang, Xiaoke | Ouyang, Z (Zhiyun)
Laboratory culture experiments were conducted with common reed (Phragmites australis) to elucidate the role of root exudates on CH₄ production in wetland soils as well as the importance of different plant organs as routes of CH₄ to the atmosphere. In the 50 d experiment period, root exudates ranged from 0.03 to 1.53 μmolg⁻¹d⁻¹, which increased with reed growth. CH₄ production rate of soil was stimulated as root exudates collected was added. CH₄ transport capacity rate also increased with plant growth and influenced by light intensity. Root tips were the most important part of controlling diffusion of CH₄ into reed shoots, and leave transport accounted for 45.34% of total emissions into the atmosphere.
Mostrar más [+] Menos [-]The Emergent Science of Engineering a Sustainable Urban Environment Texto completo
2009
Goudie, Douglas
Engineering is taking a lead role in sustainability implementation, despite problems linking institutional decision-makers with such things as water purification and cleansing wetlands. An emerging science may help speed an all-system approach to implementing sustainable urban planning. The many innovative approaches to engineering and planning will lead to cities and suburbs where water, urban travel, energy chains and food provision infrastructures are bound together by ESD values, flow-on principles and a workable process of sustainability achievement. JCU Townsville is developing such a process of Sustainability Implementation Planning (SIP) and Engineering, aspiring to become a tropics sustainability exemplar. This article reports on a 90-strong workshop: Paths to Sustainability held in August 2008, with strong regional leadership support. An integrated intellectual frame and ‘futures oriented' blueprint is provided to achieve the myriad cultural, social, economic, energy, water, food, engineering and environmental needs to ‘go sustainable' in an urban setting, where most of us live. The workshop results show SIP water management begins with local raindrops, local capture, local ground penetration, use and reuse, entering local nutrient flows to local urban food gardens and then used as a source to grow aquatic protein and fuel oils. Energy engineering becomes a local mix of renewables and innovative storage, appropriate building design, transport systems and industry; including embodied and life-cycle energy analysis and careful considerations in all built structure and use. Urban planning, people movement, housing location and travel mode will increasingly be judged by energy costs, as will food production.
Mostrar más [+] Menos [-]A Merging Algorithm for Aerosol Size Distribution from Multiple Instruments Texto completo
2009
Ondráček, J. | Ždímal, V. | Smolík, J. | Lazaridis, M.
A simple algorithm for merging aerosol number particle size distribution (AMANpsd) data from multiple instruments is presented. The code uses a multilognormal model for the evaluation of merged aerosol particle size distribution data. AMANpsd is able to recalculate the aerodynamic diameter to the mobility diameter in the cases when, e.g., the Aerodynamic Particle Sizer data need to be connected to the data obtained by the Scanning Mobility Particle Sizer. The only assumption is the lognormality of the particle size distribution. As a result, the algorithm gives the parameters of the multilognormal model (particle number concentration, geometric mean diameter, and geometric standard deviation of each single lognormal mode). The algorithm was tested on a set of data from intensive indoor/outdoor measurement campaigns performed in Prague (Czech Republic), Oslo (Norway), and Milan (Italy). The particle size distribution data set covers the range of particle mobility diameters from 2 nm up to 8 μm. The agreement between the multilognormal model and the available experimental data from multiple instruments was satisfactory.
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