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101.
Tim S. Nawrot Nino Kuenzli Jordi Sunyer Tingming Shi Teresa Moreno Mar Viana Joachim Heinrich Bertil Forsberg Frank J. Kelly Muhammad Sughis Benoit Nemery Paul Borm 《Atmospheric environment (Oxford, England : 1994)》2009,43(30):4595-4602
We assessed the extent to which constituents of PM2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium. 相似文献
102.
Domestic water conservation in arid climates can result in efficient utilization of existing water supplies. The impacts of
conservation measures such as the installation of water-saving devices, water metering and pricing schemes, water rationing
and public awareness programs, strict plumbing codes, penalties for wasting water, programs designed to reduce leakage from
public water lines and within the home, water-efficient landscaping, economic and ethical incentives are addressed in detail.
Cost savings in arid climates, with particular reference to Saudi Arabia, in relation to some conservation techniques, are
presented. Water conservation technology and tentative demonstration and implementation of water conservation programs are
discussed. 相似文献
103.
Ahmed I. El-Seesy Mohamed Nour Ali M. A. Attia Hamdy Hassan 《International Journal of Green Energy》2020,17(3):233-253
ABSTRACTThis article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in pmax. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the pmax. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NOx level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level. 相似文献
104.
Ahmed AA Mohamed A Ali AE Barakat A Abd El-Hady M El-Hussein A 《Journal of environmental radioactivity》2004,77(3):275-283
During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived (222Rn) decay products 214Pb and 210Pb. The samples were taken by using a single-filter technique and gamma-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214Pb and 210Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214Pb and 210Pb within the whole year was found to be 1.4+/-0.27 Bq m(-3) and 1.2+/-0.15 mBq m(-3), respectively. Different 210Pb:214Pb activity ratios during the year varied between 1.78 x 10(-4) and 1.6 x 10(-3) with a mean value of 8.9 x 10(-4) +/- 7.6 x 10(-5). From the ratio between the activity concentrations of the radon decay products 214Pb and 210Pb a mean residence time (MRT) of aerosol particles in the atmosphere of about 10.5+/-0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air. 相似文献
105.
Enrichment and isolation of endosulfan-degrading microorganisms 总被引:3,自引:0,他引:3
Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,3,4-benzo-dioxathiepin-3-oxide) is a cyclodiene organochlorine currently used as an insecticide all over the world and its residues are posing a serious environmental threat. This study reports the isolation and identification of enriched microorganisms, capable of degrading endosulfan. Enrichment was achieved by using the insecticide as either the sole source of carbon or sulfur in parallel studies. Two strains each of fungi (F1 and F4) and bacteria (BF2 and B4) were selected using endosulfan as a sole carbon source. A Pandoraea species (Lin-3) previously isolated in our laboratory using lindane (gamma-HCH) as a carbon source was also screened for endosulfan degradation. F1 and F4 (Fusarium ventricosum) degraded alpha-endosulfan by as much as 82.2 and 91.1% and beta-endosulfan by 78.5 and 89.9%, respectively, within 15 d of incubation. Bacterial strains B4 and Lin-3 degraded alpha-endosulfan up to 79.6 and 81.8% and beta-endosulfan up to 83.9 and 86.8%, respectively, in 15 d. Among the bacterial strains isolated by providing endosulfan as a sulfur source, B4s and F4t degraded alpha-endosulfan by as much as 70.4 and 68.5% and beta-endosulfan by 70.4 and 70.8%, respectively, after 15 d. Degradation of the insecticide occurred concomitant with bacterial growth reaching an optical density (OD600) of 0.366 and 0.322 for B4 and Lin-3, respectively. High OD600 was also noted with the other bacterial strains utilizing endosulfan as a sulfur source. Fungal and bacterial strains significantly decreased the pH of the nutrient culture media while growing on endosulfan. The results of this study suggest that these novel strains are a valuable source of potent endosulfan-degrading enzymes for use in enzymatic bioremediation. 相似文献
106.
Evaluation of groundwater and soil pollution in a landfill area using electrical resistivity imaging survey 总被引:8,自引:0,他引:8
Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse.
This study was conducted in order to determine the extent of groundwater and soil pollution within and around the landfill
of Seri Petaling located in the State of Selangor, Malaysia. The condition of nearby surface water was also determined. An
electrical resistivity imaging survey was used to investigate the leachate production within the landfill. Groundwater geochemistry
was carried out and chemical analysis of water samples was conducted upstream and downstream of the landfill. Surface water
was also analyzed in order to determine its quality.
Soil chemical analysis was performed on soil samples taken from different locations within and around the landfill in the
vadose zone (unsaturated zone) and below the water table (in the soil saturated zone). The resistivity image along line L–L1 indicated the presence of large zones of decomposed waste bodies saturated with highly conducting leachate. Analysis of trace
elements indicated their presence in very low concentrations and did not reflect any sign of heavy metal pollution of ground
and surface water or of soil.
Major ions represented by Na, K, and Cl were found in anomalous concentrations in the groundwater of the downstream bore hole,
where they are 99.1%, 99.2%, and 99.4%, respectively, higher compared to the upstream bore hole. Electrical conductivity (EC)
was also found in anomalous concentration downstream. Ca and Mg ions represent the water hardness (which is comparatively
high downstream). There is a general trend of pollution towards the downstream area. Sulfates (SO4) and nitrates (NO3) are found in the area in low concentrations, even below the WHO standards for drinking water, but are significantly higher
in the surface water compared to the groundwater. Phosphate (PO4) and nitrite (NO2), although present in low levels, are significantly higher at the downstream. There is no significant difference in the amount
of fluoride (F) in the different locations. In the soil vadose zone, heavy metals were found to be in their typical normal
ranges and within the background concentrations. Soil exchangeable bases were significantly higher in the soil saturated zone
compared to the vadose zone, and no significant difference was obtained in the levels of inorganic pollutants. With the exception
of Cd, the concentration ranges of all trace elements (Cu, Zn, Cr, Pb, and Ni) of Seri Petaling landfill soils were below
the upper limits of baseline concentrations published from different sources. 相似文献
107.
Mahrous M. Kandil Ahmed F. El-Aswad William C. Koskinen 《Journal of environmental science and health. Part. B》2013,48(7):473-483
Sorption–desorption of the insecticide imidacloprid 1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine onto a lacustrine sandy clay loam Egyptian soil and its clay and humic acid (HA) fractions was investigated in 24-h batch equilibrium experiments. Imidacloprid (IMDA) sorption–desorption isotherms onto the three sorbents were found to belong to a non-linear L-type and were best described by the Freundlich model. The value of the IMDA adsorption distribution coefficient, Kdads, varied according to its initial concentration and was ranged 40–84 for HA, 14–58 for clay and 1.85–4.15 for bulk soil. Freundlich sorption coefficient, Kfads, values were 63.0, 39.7 and 4.0 for HA, clay and bulk soil, respectively. The normalized soil Koc value for imidacloprid sorption was ~800 indicating its slight mobility in soils. Nonlinear sorption isotherms were indicated by 1/nads values <1 for all sorbents. Values of the hysteresis index (H) were <1, indicating the irreversibility of imidacloprid sorption process with all tested sorbents. Gibbs free energy (ΔG) values indicated a spontaneous and physicosorption process for IMDA and a more favorable sorption to HA than clay and soil. In conclusion, although the humic acid fraction showed the highest capacity and affinity for imidacloprid sorption, the clay fraction contributed to approximately 95% of soil-sorbed insecticide. Clay and humic acid fractions were found to be the major two factors controlling IMDA sorption in soils. The slight mobility of IMDA in soils and the hysteresis phenomenon associated with the irreversibility of its sorption onto, mainly, clay and organic matter of soils make its leachability unlikely to occur. 相似文献
108.
Ishtiyaq Ahmed Najar Anisa B. Khan 《Environmental science and pollution research international》2013,20(9):6406-6417
In the present study, potential of Eisenia fetida to recycle the different types of fresh water weeds (macrophytes) used as substrate in different reactors (Azolla pinnata reactor, Trapa natans reactor, Ceratophyllum demersum reactor, free-floating macrophytes mixture reactor, and submerged macrophytes mixture reactor) during 2 months experiment is investigated. E. fetida showed significant variation in number and weight among the reactors and during the different fortnights (P <0.05) with maximum in A. pinnata reactor (number 343.3?±?10.23 %; weight 98.62?±?4.23 % ) and minimum in submerged macrophytes mixture reactor (number 105?±?5.77 %; weight 41.07?±?3.97 % ). ANOVA showed significant variation in cocoon production (F4?=?15.67, P <0.05) and mean body weight (F4?=?13.49, P <0.05) among different reactors whereas growth rate (F3?=?23.62, P <0.05) and relative growth rate (F3?=?4.91, P <0.05) exhibited significant variation during different fortnights. Reactors showed significant variation (P <0.05) in pH, Electrical conductivity (EC), Organic carbon (OC), Organic nitrogen (ON), and C/N ratio during different fortnights with increase in pH, EC, N, and K whereas decrease in OC and C/N ratio. Hierarchical cluster analysis grouped five substrates (weeds) into three clusters—poor vermicompost substrates, moderate vermicompost substrate, and excellent vermicompost substrate. Two principal components (PCs) have been identified by factor analysis with a cumulative variance of 90.43 %. PC1 accounts for 47.17 % of the total variance represents “reproduction factor” and PC2 explaining 43.26 % variance representing “growth factor.” Thus, the nature of macrophyte affects the growth and reproduction pattern of E. fetida among the different reactors, further the addition of A. pinnata in other macrophytes reactors can improve their recycling by E. fetida. 相似文献
109.
Ahmed M. Reda Ahmed Hamza H. Ali Ibrahim S. Taha Mahmoud G. Morsy 《International Journal of Green Energy》2017,14(1):75-85
In this study, an experimental investigation on the performance of a small-scale residential-size solar-driven adsorption (silica gel-water) cooling system that was constructed at Assiut University campus, Egypt is carried out. As Assiut area is considered as hot, arid climate, field tests for performance assessment of the system operation during the summer season are performed under different environmental operating conditions. The system consists of an evacuated tube with a reflective concentration parabolic surface solar-collector field with a total area of 36 m2, a silica gel-water adsorption chiller of 8 kW nominal cooling capacity, and hot and cold water thermal storage tanks of 1.8 and 1.2 m3 in volume, respectively. The results of summer season field test show that under daily solar insolation varying from 21 to 27 MJ/m2, the solar collectors employed in the system had high and almost constant thermal efficiency. The daily solar-collector efficiency during the period of system operation ranged from about 50% to 78%. The adsorption chiller performance shows that the chiller average daily coefficient of performance (COP) was 0.41 with the average cooling capacity of 4.4 kW when the cooling-water and chilled-water temperatures were about 31°C and 19°C, respectively. As the chiller cooling water is cooled by the cooling tower in the hot arid area, the cooling water is at a higher temperature than the design point of the chiller. Therefore, an experiment was carried out using the city water for cooling. The results show that an enhancement in the chiller COP by 40% and the chilling power by 17% has been achieved when the city water was 27.7°C. 相似文献
110.
Abubakari Ahmed 《Journal of Environmental Planning and Management》2017,60(10):1741-1764
There is a growing concern about integrating biodiversity into urban planning, yet, discussions are concentrated on science-informed planning in general. Few have explored the integration of biodiversity in specific planning instruments, especially in African cities. This paper examines how and what components of biodiversity are integrated into master plans, medium-term plans, building codes, zoning codes and permits in Kumasi City, Ghana. There is limited integration of biodiversity in most planning instruments as they were mostly designed on the basis of health, safety and economy. Allied to lack of funding and public participation, biodiversity in Kumasi is under significant threat from rapid urban development. Creating an opportunity for popular participation and decentralizing the planning system could set the preconditions for local integration and revision of instruments. Simplifying the definition of biodiversity could increase local planners’ appreciation, understanding and their ability to make use of biodiversity data. 相似文献