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结果 1061-1070 的 1,310
A Quantum Statistical Approach to Remediation Effect of Humic Substances 全文
2011
N. Aleksandrova, Olga | Schulz, Marcus | Matthies, Michael
Among various remediation factors, dissolved organic matter including humic substances (HS) has substantial effect on environmental contamination significantly changing the contaminant’s degradation, bioavailability, reactivity, and immobilization. However, the effects strongly depend on HS concentrations and their aromaticity index (AI). To understand underlying phenomena of remediation action of HS, which is revealed to occur within a definite interval of HS concentrations in water solution, a quantum statistical approach is supposed. Developing this approach, a model of protons as Fermi particles in humic substances was advanced for the first time and applied to describe transformations of HS molecules, i.e., multipoles into micelle structures, which in turn provide for mediating effects in water. Sufficiently high concentration of micelle granules in water solution exists if the concentration of HS lies within a definite interval. It was demonstrated applying a grand canonical Gibbs distribution method to a statistical ensemble of HS particles. Our approach allows for understanding and quantifying some biological and physiological processes connected with mediating action of HS, as for example the reversible red cell aggregation influenced by HS, adsorption of HS particles by cancer cells, and effect of HS on human resistibility to inflammatory processes of different kinds. Application of our results to water systems may be helpful to optimize waste processing and disposal.
显示更多 [+] 显示较少 [-]Wet and Dry Deposition Fluxes of Polychlorinated Biphenyls (PCBs) in an Urban Area of Turkey 全文
2011
Günindi, Manolya | Tasdemir, Yücel
Atmospheric polychlorinated bihenyls (PCBs) deposit by dry and wet deposition mechanisms, and therefore they constitute a significant polluting source for lands and surface waters. Various samplers have been used to determine the PCB pollution level resulting from deposition. In the presented study, a modified wet deposition sampler (WDS) was used for sampling both wet and dry deposition samples with the same instrument by which wet deposition reservoir of the WDS is opened and dry deposition reservoir is closed when rain starts. Wet and dry deposition samples were collected between June 2008 and June 2009. In the samples taken from BUTAL which is known as an urban area with heavy traffic, âPCB dry deposition fluxes were determined as 18â±â10 ng/m2â−day, and wet deposition fluxes for dissolved and particle phase were measured as 480â±â1,185 and 475â±â1,000 ng/m2â−day, respectively. The dissolved and particle-phase PCB concentrations in rain were 10â±â13 and 13â±â14 ng/l, respectively. The contribution of wet deposition to total PCB deposition was determined as 52%. PCB concentrations in the ambient air were measured to be 370â±â200 and 20â±â20 pg/m3 for gas and particle phases, respectively. Washout ratio was determined by proportioning rain concentration to concentration in air. The washout ratios of the samples were between 1,675–311,800 and 12,775–2,511,120 for dissolved and particulate phases, respectively.
显示更多 [+] 显示较少 [-]Stability of Fe- and Mn-(oxyhydr)oxides in Common Soil Dispersion Solutions 全文
2011
Manh, Phung N. | Ali Khan, Moonis | Jeon, Byong-Hun | Kim, Jae Gon | Lee, Giehyeon
Soil dispersion is a prerequisite process for the separation of metal oxides from bulk soil when magnetic separation is employed to enhance the efficiency for soil treatment. This study examined the stability of goethite, hematite, birnessite, and manganite in common dispersion solutions. The stability of pH in the oxide suspension decreased in the order carbonate (50Â mM Na2CO3) > pyrophosphate (50Â mM Na4P2O7) > simple alkaline (1Â mM NaOH) solutions regardless of the oxides. Dissolution of the four oxides was negligible in the carbonate and the simple alkaline solutions. In the pyrophosphate solutions, however, the oxides were subject to ligand-promoted dissolution by pyrophosphate ion. The extent of dissolution was highest for goethite followed by manganite, hematite, and birnessite. Dissolved Fe and Mn concentrations reached 68.3 and 4.1Â μM for goethite and manganite suspensions, respectively, in 21Â days with 5Â mM pyrophosphate. Higher pyrophosphate concentrations (up to 150Â mM) did not substantially affect the extent of ligand-promoted dissolution due to the limited surface sites of the oxides. The results of this study suggest that the carbonate solution would be more desirable than the simple alkaline or the pyrophosphate solution for soil dispersion in the presence of common Fe or Mn oxides.
显示更多 [+] 显示较少 [-]Study of Ni(II), Cu(II), Pb(II), and Zn(II) Removal Using Sludge and Minerals Followed by MF/UF 全文
2011
Malamis, Simos | Katsou, Evina | Haralambous, Katherine J.
This work examined the removal of heavy metals in a system consisting of ultrafiltration (UF) or microfiltration (MF) membranes combined with sludge and minerals. The metals under examination were Ni(II), Cu(II), Pb(II), and Zn(II), while the system performance was investigated with respect to several operating parameters. Metal removal was achieved through various processes including chemical precipitation, biosorption, adsorption, ion exchange, and finally retention of the metals by the membranes. The pH had a profound effect on metal removal, as the alkaline environment favored the metal removal process. The use of sludge resulted in increased levels of metal uptake which was further enhanced with the addition of minerals. The metal removal mechanisms depended on the pH, the metal, and mineral type. The combined sludge–mineral–UF system could effectively remove metal ions at an alkaline environment (pH = 8), meeting the US EPA recommended long-term reuse limits of lead and copper and the short-term reuse limits of nickel and zinc for irrigation purposes, provided that specific mineral dosages were added.
显示更多 [+] 显示较少 [-]Atmospheric Emission Inventory for Natural and Anthropogenic Sources and Spatial Emission Mapping for the Greater Athens Area 全文
2011
Aleksandropoulou, Victoria | Torseth, Kjetil | Lazaridis, M.
A spatially, temporally and chemically resolved emission inventory for particulate matter and gaseous species from anthropogenic and natural sources was created for the Greater Athens Area (GAA; base year, 2007). Anthropogenic sources considered in this study include combustion (industrial, non-industrial, commercial and residential), industrial production, transportation, agriculture, waste treatment and solvent use. The annual gaseous pollutants (ΝΟx, SOx, non-methane volatile organic compounds (NMVOCs), CO and ΝΗ3) and particulate matter (PM2.5 and PM2.5–10) emissions were derived from the UNECE/EMEP database for most source sectors (SNAP 1–9; 50 × 50 km2) and their spatial resolution was increased using surrogate spatial datasets (land cover, population density, location and emissions of large point sources, emission weighting factors for the GAA; 1 × 1 km2). The emissions were then temporally disaggregated in order to provide hourly emissions for atmospheric pollution modelling using monthly, daily and hourly disintegration coefficients, and additionally the chemical speciation of size-segregated particles and NMVOCs emissions was performed. Emissions from agriculture (SNAP 10) and natural emissions of particulate matter from the soil (by wind erosion) and the sea surface and of biogenic gaseous pollutants from vegetation were also estimated. During 2007 the anthropogenic emissions of CO, SOx, NOx, NMVOCs, NH3, PM2.5 and PM2.5–10 from the GAA were 151,150, 57,086, 68,008, 38,270, 2,219, 9,026 and 3,896 Mg, respectively. It was found that road transport was the major source for CO (73.3%), NMVOCs (31.6%) and NOx (35.3%) emissions in the area. Another important source for NOx emissions was other mobile sources and machinery (23.1%). Combustion for energy production and transformation industries was the major source for SOx (38.5%), industrial combustion for anthropogenic PM2.5–10 emissions (59.5%), whereas non-industrial combustion was the major source of PM2.5 emissions (49.6%). Agriculture was the primary NH3 source in the area (72.1%). Natural vegetation was found to be an important source of VOCs in the area which accounted for approximately the 5% of total VOCs emitted from GAA on a typical winter day. The contribution of sea-salt particles to the emissions of PM2.5 was rather small, whereas the emissions of resuspended dust particles exceeded by far the emissions of PM2.5 and PM2.5–10 from all anthropogenic sources.
显示更多 [+] 显示较少 [-]Influence of Airborne Pollution on Cd, Zn, Pb, Cu, and Al Accumulation and Physiological Parameters of Plant Leaves in Antakya (Turkey) 全文
2011
Doğanlar, Zeynep Banu | Atmaca, Mustafa
In this study, the effects of industrial and urban pollution on Pb, Al, Cd, Cu, and Zn accumulation, peroxidase activity, and pigment and protein contents were investigated in shrub and tree leaves in Antakya, Turkey. We determined that industrial and traffic activities produce the most plant-incorporated air pollutants in Antakya City. Cu and Al amounts were high in plants in the urban street location and Cd, Pb, and Zn amounts where high for all plants in the industrial site. Acer negundo L. showed maximum Pb and Zn accumulation at the industrial site and Al accumulation for the urban street site. Higher Cd and Cu amounts were detected in Platanus orientalis L. and Nerium oleander L. in the industrial and urban street sites, respectively. Compared to the control site, decreases in pigment and total soluble protein contents and increases in peroxidase enzyme activity were more evident in industrial and urban street sites. Our results indicated that industry and urban air pollution is high in Antakya City and Pb pollution was at an especially alarming level for vegetation and human health.
显示更多 [+] 显示较少 [-]Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability 全文
2011
Gallego, José Luis R. | Sierra, Carlos | Permanyer, Albert | Peláez, Ana I. | Menéndez-Vega, Demelza | Sánchez, Jesús
Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability 全文
2011
Gallego, José Luis R. | Sierra, Carlos | Permanyer, Albert | Peláez, Ana I. | Menéndez-Vega, Demelza | Sánchez, Jesús
Here, we addressed biodegradation vs. volatilization processes, and also bioavailability limitations during biopile remediation of soil initially contaminated by more than 5,000 mg/kg of hydrocarbons. In order to select bioremediation strategies, we first conducted a biotreatability study, which included geochemical, textural, and microbiological characterization of the soil matrix. Next, we implemented five bioremediation approaches onsite in real-scale biopiles. In order to monitor hydrocarbon depletion and to distinguish between biological and non-biological processes, we analyzed chemical biomarkers by means of gas chromatography–mass spectrometry. In addition, a comprehensive study of soil grain size and its implications on bioavailability were studied. Furthermore, the evolution of microbial populations was also examined. Two of the strategies implemented in the biopiles (the combination of a slow-release fertilizer and a surfactant, and the use of an oleophilic fertilizer respectively) reduced the soil hydrocarbon content to under 500 mg/kg in 5 months. Additional results from this study indicate that volatilization was the predominant degradation process for light hydrocarbons (below 12 carbon atoms), whereas heavier compounds were mainly biodegraded. However, even in the most favorable situation, a residual concentration of hydrocarbons linked to the finer fraction of the soil was found.
显示更多 [+] 显示较少 [-]Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability 全文
2011
Rodríguez Gallego, José Luis | Sierra Fernández, Carlos | Permanyer Bastardas, Albert | Peláez Andrés, Ana Isabel | Menéndez Vega, Demelza | Sánchez Martín, Jesús
We thank the company EMGRISA (Spain) for financial and technical support.
显示更多 [+] 显示较少 [-]Identification, Apportionment, and Photochemical Reactivity of Non-methane Hydrocarbon Sources in Busan, Korea 全文
2011
Choi, Eunhwa | Heo, Jong-Bae | Hopke, Philip K. | Jin, Byong-Bok | Yi, Seung-Muk
Hourly concentrations of non-methane hydrocarbons (NMHCs) recorded between June and August 2006, at two monitoring sites (Gijang and Jin) in Busan were analyzed to examine the characteristics and photochemical reactivity of NMHC sources. The two sites represent urban (Jin) and suburban (Gijang) Busan, which is a typical Korean city. Positive matrix factorization (PMF), applied to identify and apportion the sources of NMHCs, revealed nine sources for Gijang and ten sources for Jin. To explore the contribution of each NMHC source to ozone formation at the two sampling sites, the ozone formation potential was estimated for each source. The largest contributors to ozone formation were sources characterized by 1,2,3-trimethylbenzene (26.4%) at Gijang and by toluene, ethylbenzene, and xylenes (22.5%) at Jin, which were composed mostly of heavy hydrocarbons and aromatics. Secondary sources included two coating sources (20.9%, 12.2%) and vehicle exhaust (10.3%) at Gijang and a source represented by toluene (17.4%), vehicle exhaust (15.9%), and a coating-2 source (9.6%) at Jin. Conditional probability function (CPF) and potential source contribution function (PSCF) analysis methods were used to identify the directions of local sources and to locate potential source regions, respectively. The CPF and PSCF results agreed well for the majority of sources resolved by PMF and thus were very useful in identifying the major sources contributing to ozone formation at the two study sites.
显示更多 [+] 显示较少 [-]Vulnerability of Coastal Aquifers Due to Nutrient Pollution from Agriculture: Kalpitiya, Sri Lanka 全文
2011
Jayasingha, Pathmakumara | Pitawala, A. | Dharmagunawardhane, H. A.
This study focuses on spatial and temporal nutrient pollution of groundwater in the unconfined sandy aquifers of Kalpitiya peninsula, Sri Lanka, where agricultural activities are intense. The study covers two consecutive dry and rainy seasons during the period from 2008 to 2010. Nitrate is the dominant nutrient pollutant in groundwater. The values of Nitrate-N contents ranged from 0.60 to 212.40 mg/L in the dry seasons and 0.20–148.50 mg/L in rainy seasons. Phosphate in groundwater ranged from 0.20 to 5.70 mg/L in dry seasons and 0.04–10.35 mg/L with few exceptions in rainy seasons. About 50% of the studied water samples had Nitrate-N concentrations above WHO drinking water guideline values both in dry and rainy periods. These high concentrations were recorded from wells in agricultural lands. Although there is a slight decrease in the Nitrate-N concentrations at random in rainy seasons, an increasing trend of average concentrations became evident over the study period as a whole, probably indicating building up of Nitrate-N in groundwater in the vegetable growing areas. The spatial distribution of Nitrate-N too shows a good match of high Nitrate-N bearing zones with vegetable cultivated areas indicating intensive leaching from application of excessive chemical fertilizers. High Nitrate-N zones also showed fairly steady lateral distribution indicating slow lateral mobility of Nitrate-rich groundwater probably due to low hydraulic gradients. Low phosphate concentrations in both groundwater and surface soils either indicates their less use in the area or that the available phosphate is leached and removed from the aquifer water and (sandy) soil solutions and probably adsorbed in clayey deeper horizons. Low concentrations of major cations (especially K, Ca, and Na) indicate less impact on cation concentrations in groundwater by the fertilizer application or sea water intrusions/up-coning.
显示更多 [+] 显示较少 [-]Dynamics of Atmospheric Aerosol Number Size Distributions in the Eastern Mediterranean During the “SUB-AERO” Project 全文
2011
Ždímal, Vladimir | Smolík, Jiri | Eleftheriadis, Kostas | Wagner, Zdeněk | Housiadas, Christos | Mihalopoulos, Nikos | Mikuška, Pavel | Večeřa, Zbynek | Kopanakis, Ilias | Lazaridis, Mihalis
Measurements of number size distributions of submicron aerosols have been performed at the Eastern part of Mediterranean as part of an extensive measurement campaign to study photo-oxidants and aerosols (SUB-AERO Project). The measurements were made at the Finokalia station on the island of Crete (Greece) and onboard the research vessel “Aegaeon”. Two campaigns were performed during July 2000 and January 2001 using two scanning mobility particle sizers. The particle distributions measured in the range between 7.8 < d p < 327 nm during the summer measurements and between 7.5 < d p < 316 nm during the winter measurements, where d p is the mobility particle diameter. The concentration of ultrafine particles (7.5 < d p < 30 nm) was higher during the winter period and varied mainly between 5 × 10¹ and 2 × 10³ cm⁻³ with concentration peak values for this mode exceeding 1 × 10⁴ cm⁻³. During the summer campaign, an average number concentration of 1 × 10² cm⁻³ at Finokalia and about 5 × 10¹ cm⁻³ aboard the “Aegaeon” vessel was measured. An average concentration of 1 × 10³ cm⁻³ was measured for the particles in the size range between 30 and 100 nm, whereas in the size range 100-300 nm, the measured concentration ranged between 1 × 10² and 5 × 10³ cm⁻³. Diurnal patterns in number concentrations were observed in connection with the transport of air masses and local sources. During the winter period, three nucleation events were observed in connection with the appearance of a particle mode at 20 nm.
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