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Removal of Pentachlorophenol by Adsorption on Magnetite-immobilized Chitin Полный текст
2007
Pang, K. M. | Ng, S. | Chung, W. K. | Wong, P. K.
The application of magnetite-immobilized chitin in pentachlorophenol (PCP) removal was demonstrated in this study. The physicochemical parameters for immobilization of chitin by magnetite, and for PCP adsorption using magnetite-immobilized chitin were optimized. For chitin immobilization, the optimized conditions were: magnetite to chitin (m:c) ratio at 1:2, initial pH 6, 25°C, 200 rpm and 60 min in batch system. The immobilization efficiency (IE) was 99.4% and immobilization capacity (IC) was 2.0 mg chitin mg-¹ magnetite. High initial pH (pH > 11) and temperature (>30°C) lowered the IE and IC. For PCP (10 mg l-¹) adsorption, the optimized conditions were: 1,500 mg l-¹ immobilized chitin, initial pH 6, 25°C, 200 rpm and 60 min in batch system. The removal efficiency (RE) was 57.9% and removal capacity (RC) was 5.4 mg g-¹. The adsorption ability of immobilized chitin decreased with pH and temperature increased. However, increasing the amount of immobilized chitin (24,000 mg l-¹) can increase the RE up to 92%. Both chitin immobilization and PCP adsorption exhibited Langmuir and Freundlich adsorption isotherms. Results in this study indicated that magnetite-immobilized chitin was a cost-effective and environmental friendly adsorbent to remove environmental pollutants such as PCP.
Показать больше [+] Меньше [-]Organic-geochemical Differentiation of Petroleum-type Pollutants and Study of Their Fate in Danube Alluvial Sediments and Corresponding Water (Pančevo Oil Refinery, Serbia) Полный текст
2007
Jovančićević, Branimir | Vrvić, Miroslav | Schwarzbauer, Jan | Wehner, Hermann | Scheeder, Georg | Vitorović, Dragomir
A review is given in this paper of the up-to-date results observed in differentiation and transformation studies on petroleum-type pollutants in underground and surface waters. Water and particulate matter derived from the locality of Pančevo Petroleum Refinery, Serbia (River Danube alluvial formations). It was shown that distributions of n-alkanes, steranes and triterpanes, and δ¹³CPDB values of n-alkanes may successfully be used for qualitatively differentiating the petroleum-type pollutants from native organic matter in recent sedimentary formations. In underground waters, a petroleum-type pollutant is exposed to microbiological degradation which is manifested through relatively fast degradation of n-alkanes. Following an almost complete degradation of crude oil n-alkanes in underground water, the biosynthesis of novel, even carbon-number C₁₆-C₃₀ n-alkanes may be observed. It is shown that the n-alkane distribution observed in a petroleum-type pollutant may depend on the intensity of its previous interaction with water. The fate of petroleum-type pollutants in environmental waters may be predicted through laboratory simulative microbiological degradation experiments by using microorganism consortiums similar to those observed under relevant natural conditions, as well as on corresponding nutrient base.
Показать больше [+] Меньше [-]PM₁₀-bound Polycyclic Aromatic Hydrocarbons (PAHs) and Cancer Risk Estimation in the Atmosphere Surrounding an Industrial Area of Shanghai, China Полный текст
2007
Cheng Jinping. | Yuan, Tao | Wu, Qian | Zhao, Wenchang | Xie, Haiying | Ma, Yingge | Ma, Jing | Wang, Wenhua
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in the urban atmosphere. In particular, atmospheric pollution has increasingly become severe in China due to its rapid urbanization and industrialization. In recent years, a few studies have presented information about POPs (such as PAHs, PCBs, OCPs) in aerosols at a molecular level in a limited number of cities such as Beijing, Qingdao and Guangzhou, as well as Hong Kong. Whereas, these cities are located in northern and southern China, respectively, where characteristics of atmospheric pollution might be different from those in the eastern cities, such as Shanghai. Atmospheric particle pollution is a persistent problem in Shanghai, a typical metropolis of China, which has several huge industrial regions. In order to gain a comprehensive understanding of the present state, properties and sources of PAHs pollution in Shanghai, PM₁₀ samples were collected at Coal-Fired Power Plant (CFP), Chlor-Alkali Chemical factory (CAC) and Coking and Chemical factory (CCF) in an industrial area, during the period, November 2004-September 2005. The concentrations of 16 PAHs were analyzed using the HPLC with UV visible detector. The results showed that the mean value of total PAHs in the industrial area was 64.85 ng m-³; 3-ring PAHs were found at low levels, while 4-, 5- and 6-ring PAHs were found at high levels. The levels of BaP were 3.07 and 7.16 ng m-³ at Chlor-Alkali Chemistry Factory and Coking and Chemistry Factory sites, respectively. PAHs levels exhibited distinct seasonal variation, with the highest level in autumn and the lowest in summer. The major source of PAHs at the industrial area was fossil fuel combustion, coal-burning, industrial furnaces including others. There was a very significant correlation of PAHs levels between CCF and CAC (R ² = 0.91). The average concentration of BaP in the industrial area during the sampling period was 5.95 ng m-³. It could be concluded the local population appears to be exposed to significantly high cancer risk (exceeding 2 ng m-³ in autumn and winter) as compared to the population of other areas.
Показать больше [+] Меньше [-]Recovery of Acidified Streams in Forests Treated by Total Catchment Liming Полный текст
2007
Westling, Olle | Zetterberg, Therese
Reduced emissions of acidifying pollutants have changed the acidification process, and as a result, forest soils and surface waters are slowly recovering in Sweden. However, model calculations show that some areas may never recover completely unless further measures, such as liming, are undertaken. Liming of surface waters (lakes, rivers and wetlands) has been successfully practised in Sweden since the 1970s, but repeated treatments are necessary. A full recovery of acidified lakes and streams without frequent liming is however not possible until soil acidification is reversed in the most strongly affected areas. In this study, the recovery of acidified streams was examined using 'the total catchment approach' i.e. treatment of both recharge and discharge areas. The aim was to compare the quantitative effect of different treatments on run off chemistry and the recovery of brown trout. Catchments in southwest Sweden were treated with a combination of 2 tons of wood ash and 4, 6 or 12 tons of crushed limestone per hectare in 1998/1999. Treatment of both recharge and discharge areas resulted in fast and significant changes in stream water quality, e.g. increased concentrations of calcium, higher pH and ANC and a decreased concentration of inorganic aluminium. The initial changes were dependent on the distribution of the applied lime between discharge and recharge areas rather than the average dose on the total catchment. Treatment of recharge areas only, resulted in smaller but still significant effects on calcium, pH and ANC in stream water. Furthermore, there was an initial leaching of nitrate but it was only minor compared with the elevated leaching that occurs after a clear-cut. As a result of the treatments, brown trout is now successfully reproducing.
Показать больше [+] Меньше [-]The Influence of Heavy Metals and Mineral Nutrient Supply on Bituminaria bituminosa Полный текст
2007
Walker, David J. | Bernal, M Pilar | Correal, Enrique
With a view to the selection of plants for the re-vegetation of contaminated, semi-arid land, two populations of the perennial species Bituminaria bituminosa (Fabaceae) from the south of Spain were studied: one (“LA”) from a non-contaminated soil and the other (“C2”) from a similar soil having elevated total levels of Pb and Zn (1,112 and 4,249 μg g-¹, respectively). For sand-cultured plants receiving nutrient solution, flow cytometry showed that heavy metals, at the concentrations measured in aqueous extracts from contaminated soils, had only slight genotoxic effects on root tip cell nuclei. Both populations were also grown in both soils, in two pot experiments. In the first, shoot biomass of LA and C2 in the contaminated soil was decreased to similar extents, with respect to the “clean” soil. Tissue heavy metal concentrations were unlikely to have been phytotoxic, except in the case of shoot Zn for population LA, but there were tissue deficiencies of P and K for populations LA and C2, respectively. In the second pot assay, the stimulation of growth by NPK fertiliser confirmed that even though this soil had high total heavy metal levels, nutrient availability was the principal factor limiting growth. The lesser transport of heavy metals (Cd, Mn and Zn) to the shoot by the population from the contaminated site is a factor that should be considered when selecting B. bituminosa lines for the phytostabilisation of such sites.
Показать больше [+] Меньше [-]Effects of Changed Soil Conditions on the Mobility of Trace Metals in Moderately Contaminated Urban Soils Полный текст
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.
Показать больше [+] Меньше [-]Relationship Between Sulphate Starvation and Chromate Reduction in a H₂-fed Fixed-film Bioreactor Полный текст
2007
Battaglia-Brunet, F. | Michel, C. | Joulian, C. | Ollivier, B. | Ignatiadis, I.
While developing a low-sulphate system combining indirect chromate-reduction by biologically-produced hydrogen sulphide and direct biological chromate-reduction to treat chromate-bearing waters, the aim of the present work was to evaluate the influence of sulphate and H₂ starvation on chromate reduction. Chromate-reduction was performed under continuous-feed conditions in a fixed-film column bioreactor originally inoculated with a bacterial consortium containing Desulfomicrobium norvegicum, and fed with H₂. With 500 mg l-¹ of sulphate in the feed solution, total chromate-reduction was observed in the effluent whereas sulphate-reduction was strongly decreased, as also confirmed by measurements of isotopic ratios for sulphur. In the absence of sulphate, a chromate-reduction activity was still observed but was lower than in the presence of sulphate, and chromate-reduction was H₂-dependent. Molecular biology techniques revealed the composition of the bacterial population in the effluent. D. norvegicum together with other micro-organisms of the Bacteria domain were detected. They include members related to the genera Acinetobacter, Acetobacterium and Rhodocyclus. Even when sulphate-reduction was strongly decreased, the presence of sulphate enhances the efficiency of the H₂-dependent chromate-reduction. A H₂- and CO₂-consuming bacterial population may be used in a globally autotrophic process to reduce chromate at low sulphate concentration, thus avoiding excess sulphide production.
Показать больше [+] Меньше [-]Water Quality Retrievals from High Resolution Ikonos Multispectral Imagery: A Case Study in Istanbul, Turkey Полный текст
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.
Показать больше [+] Меньше [-]A Synoptic Climatological Approach to Assess Climatic Impact on Air Quality in South-central Canada. Part I: Historical Analysis Полный текст
2007
Cheng, Chad Shouquan | Campbell, Monica | Li, Qian | Li, Guilong | Auld, H. | Day, Nancy | Pengelly, David | Gingrich, Sarah | Ye, Zhiming
Automated synoptic weather typing and robust orthogonal stepwise regression analysis (via principal components analysis) were applied together to develop within-weather-type air pollution prediction models for a variety of pollutants (specifically, carbon monoxide – CO, nitrogen dioxide – NO₂, ozone – O₃, sulphur dioxide – SO₂, and suspended particles – SP) for the period 1974–2000 in south-central Canada. The SAS robust regression procedure was used to limit the influence of outliers on air pollution prediction algorithms. Six-hourly Environment Canada surface observed meteorological data and 6-hourly US National Centers for Environmental Prediction (NCEP) reanalysis data of various weather elements were used in the analysis. The models were developed using two-thirds of the total years for meteorological and air pollution data; the remaining one-third (randomly selected) was used for model validation. Robust stepwise regression analysis was performed to analytically determine the meteorological variables that might be used to predict air pollution concentrations. There was a significant correlation between observed daily mean air pollution concentrations and model predictions. About 20, 50, and 80% of the 80 prediction models across the study area possessed R ² values ≥ 0.7, 0.6, and 0.5, respectively. The results of model validation were similar to those of model development, with slightly smaller model R ² values.
Показать больше [+] Меньше [-]Polycyclic Aromatic Hydrocarbons (PAHs) in the Aerosol of Higashi Hiroshima, Japan: Pollution Scenario and Source Identification Полный текст
2007
Fon, Tham Yasmin Wai | Noriatsu, Ozaki | Hiroshi, Sakugawa
Polycyclic aromatic hydrocarbons (PAHs) are considered to be atmospheric pollutants and well-known human carcinogens. This study analyzes the pollution scenarios of PAHs in the aerosol of Higashi Hiroshima, Japan. We examined the characteristics, the influences of meteorological conditions, the distribution and seasonal variation of PAHs in aerosol samples collected from June 2000 to May 2001. The concentration of PAHs in the aerosol of Higashi Hiroshima was ranging from 11.8 to 157.5 μg/g with a mean concentration of 63.4 μg/g. Results showed that there is positive correlation between aerosol PAH concentrations and ambient temperature but a relatively little correlation with solar radiation. Seasonal variation was observed with a higher concentration during winter and lower concentration during summer. Apart from that, principal component analysis and molecular diagnostic ratios were also used to characterize and identify possible PAHs emission sources. Results obtained strongly suggested that vehicular emissions appeared to be the major source of aerosol PAHs in this study although other sources do have some degree of influence.
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