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Результаты 1241-1250 из 1,299
Degradation and detoxification of acid orange 52 by Pseudomonas putida mt-2: a laboratory study
2011
Mansour, Hedi Ben | Ghedira, Kamel | Barillier, Daniel | Ghedira, Leila Chekir | Mosrati, Ridha
INTRODUCTION: Acid orange 52 (AO52), extensively used in textile industries, was decolorized by Pseudomonas putida mt-2. AO52 azoreduction products such as N,N′-dimethyl-p-phenylenediamine (DMPD) and 4-aminobenzenesulfonic acid (4-ABS), were identified in the static degradation mixture. These amines were identified only in media of static incubation, which is consistent with their biotransformation under shaken incubation (aerobic conditions). MATERIALS AND METHODS: Tests with azo products were carried out, and whole cells were found able to easily degrade DMPD contrary to 4-ABS. However, this last could be attacked by cell extract, and an oxygen uptake was observed during the reaction. RESULTS: Degradation of DMPD by entire cells led to the formation of catechol. These results show that P. putida was able to decolorize AO52 and metabolize its derivative amines. In addition, the ability of tested compounds was evaluated in vitro to reduce human plasma butyrylcholinesterase (BuChE) activity. CONCLUSION: Azoreduction products seem to be responsible for BuChE inhibition activity observed in static biodegradation extract. However, toxicity of AO52 completely disappears after shaken incubation with P. putida, suggesting that bacterium has a catabolism which enables it to completely degrade AO52 and especially, to detoxify the dye mixture.
Показать больше [+] Меньше [-]Structural isomers of polyfluorinated di- and tri-alkylated phosphate ester surfactants present in industrial blends and in microwave popcorn bags
2011
Trier, Xenia | Nielsen, Nikoline Juul | Christensen, Jan H.
INTRODUCTION: In this study, we provide strategies for detecting and quantifying the structural isomers of polyfluorinated di- and tri-alkyl surfactants (PFAS) by mass spectrometry (MS). We specifically investigate polyfluorinated dialkylated phosphate ester surfactants (x:2/y:2 diPAPS, (F(CF2) x CH2CH2O-P(O)(O)−-OCH2CH2(CF2) y F)) and their thioether analogues (x:2/y:2 S-diPAPS, F(CF2) x CH2CH2SCH2-C[CH2O)2P(O)(O)−]-CH2SCH2CH2(CF2) y F), which are used for industrial applications, such as oil- and water-repellent coatings on paper and board. DiPAPS have been found in human blood and are metabolised to the persistent perfluoroalkyl carboxylic acids (PFCA) in rats. MATERIALS AND METHODS: A microwave popcorn bag extract was analysed by ultrahigh-pressure liquid chromatography coupled to a negative electrospray ionisation-quadrupole time-of-flight MS. RESULTS AND DISCUSSION: The extract contained S-diPAPS, diPAPS and trialkylated (triPAPS) impurities. TriPAPS were also present in industrial and synthetic diPAPS standards, and were verified with an 8:2/8:2/8:2 triPAPS standard. The eight elemental compositions (m/z’s) of diPAPS in the extract represent 19 precursor ion structures, and the six S-diPAPS m/z’s represent at least 13 structures. The diPAPS had [M-H]− precursor ions of m/z 789, 889,…1,489 and the S-diPAPS of m/z 921, 1,021,…1,421, corresponding to fluorinated chains from C6–18. Each m/z appeared as one to three chromatographic peaks of structural isomers, where, e.g. m/z 1,189 was present as 10:2/10:2, 8:2/12:2 and 6:2/14:2 diPAPS. The isomers formed different products ions, thus only half of the m/z 1,189 diPAPS concentration was measured with one precursor ion > product ion transition. CONCLUSION: In general, knowledge about structural isomers of poly-alkylated PFAS is needed for the estimation of types and amounts of perfluorinated degradation products, such as PFCA from diPAPS.
Показать больше [+] Меньше [-]Net anthropogenic nitrogen accumulation in the Beijing metropolitan region
2011
Han, Yuguo | Li, Xuyong | Nan, Zhe
Background, aim, and scope A rapid increase in anthropogenic nitrogen inputs has a strong impact on terrestrial and aquatic ecosystems. We have estimated net anthropogenic nitrogen accumulation (NANA) as an index of nitrogen (N) pollution potential in the Beijing metropolitan region, China. Our research provides a basis for understanding the potential impact of anthropogenic N inputs on environmental problems, such as nation-wide water quality degradation under the current rapid urban expansion in modern China. Methods The NANA estimation is based on an inventory of atmospheric N deposition, N fertilizer use, consumption of human food and animal feed, N fixation, and riverine N import and export. We calculated N accumulation values for the years 1991, 1997, 2003, and 2007. Results and discussion The average NANA values for the urban and suburban areas from 1991 to 2007 were 24,038 and 13,090 kg N km⁻² year⁻¹, respectively. NANA is higher in eastern and southern areas than in northern and western areas, and higher in the urban area than in the suburban area. The overall average NANA in Beijing has a downward trend from 15,187 kg N km⁻² year⁻¹ in 1991 to 11,606 kg N km⁻² year⁻¹ in 2007, but is still two to five times as that of developed countries. N input from nitrogenous fertilizer is the largest source of NANA, accounting for 44.4% (6,764 kg N km⁻² year⁻¹) of the total N input, followed by atmospheric N deposition and N in human food and animal feed. NANA is closely related to land use, on average 23,140 kg N km⁻² year⁻¹ in densely populated developed land, 17,904 kg N km⁻² year⁻¹ in agricultural land, and 10,445 kg N km⁻² year⁻¹ in forest land. Human population density is the best single predictor of NANA.
Показать больше [+] Меньше [-]Concentration-dependent RDX uptake and remediation by crop plants
2011
Chen, Diejun | Liu, Z Lewis | Banwart, Wanye
The potential RDX contamination of food chain from polluted soil is a significant concern in regards to both human health and environment. Using a hydroponic system and selected soils spiked with RDX, this study disclosed that four crop plant species maize (Zea mays), sorghum (Sorghum sudanese), wheat (Triticum aestivum), and soybean (Glycine max) were capable of RDX uptake with more in aerial parts than roots. The accumulation of RDX in the plant tissue is concentration-dependent up to 21 mg RDX/L solution or 100 mg RDX/kg soil but not proportionally at higher RDX levels from 220 to 903 mg/kg soil. While wheat plant tissue harbored the highest RDX concentration of 2,800 μg per gram dry biomass, maize was able to remove a maximum of 3,267 μg RDX from soil per pot by five 4-week plants at 100 mg/kg of soil. Although RDX is toxic to plants, maize, sorghum, and wheat showed reasonable growth in the presence of the chemical, whereas soybeans were more sensitive to RDX. Results of this study facilitate assessment of the potential invasion of food chain by RDX-contaminated soils.
Показать больше [+] Меньше [-]Source apportionment of PM₁₀ and PM₂.₅ at multiple sites in the strait of Gibraltar by PMF: impact of shipping emissions
2011
Pandolfi, Marco | Gonzalez-Castanedo, Yolanda | Alastuey, A (Andrés) | de la Rosa, Jesus D | Mantilla, Enrique | de la Campa, A Sanchez | Querol, X (Xavier) | Pey, Jorge | Amato, F (Fulvio) | Moreno, Teresa
Background The impact of shipping emissions on urban agglomerations close to major ports and vessel routes is probably one of the lesser understood aspects of anthropogenic air pollution. Little research has been done providing a satisfactory comprehension of the relationship between primary pollutant emissions, secondary aerosols formation and resulting air quality. Materials and methods In this study, multi-year (2003-2007) ambient speciated PM₁₀ and PM₂.₅ data collected at four strategic sampling locations around the Bay of Algeciras (southern Spain), and positive matrix factorisation model were used to identify major PM sources with particular attention paid to the quantification of total shipping emissions. The impact of the emissions from both the harbour of Algeciras and vessel traffic at the Western entrance of Mediterranean Sea (Strait of Gibraltar) were quantified. Ambient levels of V, Ni, La and Ce were used as markers to estimate PM emitted by shipping. Results and discussion Shipping emissions were characterised by La/Ce ratios between 0.6 and 0.8 and V/Ni ratios around 3 for both PM₁₀ and PM₂.₅. In contrast, elevated La/Ce values (1-5) are attributable to emissions from refinery zeolitic fluid catalytic converter plant, and low average V/Ni values (around 1) result mainly from contamination from stainless steel plant emissions. The direct contribution from shipping in the Bay of Algeciras was estimated at 1.4-2.6 μg PM₁₀/m³ (3-7%) and 1.2-2.3 μg PM₂.₅/m³ (5-10%). The total contribution from shipping (primary emissions + secondary sulphate aerosol formation) reached 4.7 μg PM₁₀/m³ (13%) and 4.1 μg PM₂.₅/m³ (17%).
Показать больше [+] Меньше [-]Mercury distribution in seawater discharged from a coal-fired power plant equipped with a seawater flue gas desulfurization system
2011
Liu, Xiyao | Sun, Lumin | Yuan, Dongxing | Yin, Liqian | Chen, Jinsheng | Liu, Yaoxing | Liu, Chengyu | Liang, Ying | Lin, Fangfang
BACKGROUND AND PURPOSE: More and more coal-fired power plants equipped with seawater flue gas desulfurization systems have been built in coastal areas. They release large amount of mercury (Hg)-containing waste seawater into the adjacent seas. However, very limited impact studies have been carried out. Our research targeted the distribution of Hg in the seawater, sediment, biota, and atmosphere, and its environmental transportation. METHODS: Seawater samples were collected from five sites: 1, sea areas adjacent to the power plant; 2, near discharge outlets; 3, the aeration pool of the power plant; and 4 and 5, two reference sites. The total gaseous Hg was determined in situ with a Tekran 2537B. Analyses of total Hg (TM) followed the USEPA methods. RESULTS: In most part of the study area, TM concentrations were close to the reference values and Hg transfer from the seawater into the sediment and biota was not obvious. However, in the aeration pool and near the waste discharge outlets, atmospheric and surface seawater concentrations of TM were much higher, compared with those at a reference site. The concentration ranges of total gaseous Hg and TM in seawater were 3.83–8.60 ng/m3 and 79.0–198 ng/L near the discharge outlets, 7.23–13.5 ng/m3 and 186–616 ng/L in the aeration pool, and 2.98–4.06 ng/m3 and 0.47–1.87 ng/L at a reference point. CONCLUSIONS: This study suggested that the Hg in the flue gas desulfurization waste seawater was not only transported and diluted with sea currents, but also could possibly be transferred into the atmosphere from the aeration pool and from the discharge outlets.
Показать больше [+] Меньше [-]Impact of long-range transport and under-cloud scavenging on precipitation chemistry in East China
2011
Li, Yuhua | Wang, Yan | Ding, Aijun | Liu, Xiaohuan | Guo, Jia | Li, Penghui | Sun, Minghu | Ge, Fuling | Wang, Wenxing
INTRODUCTION: Two hundred twenty-five precipitation samples were collected at high- (summit, 1,534 m ASL) and low-elevation (base, 218 m ASL) sites between 2005 and 2008 in eastern China. The present work focused on the roles of long-range transport and under-cloud/boundary layer scavenging on chemical composition of precipitation collected at the two sites. METHODS: Ionic and trace species were analyzed in 225 precipitation samples. A total of 72 precipitation events occurring simultaneously at the summit and base sites were further examined. Positive matrix factorization (PMF) and backward air mass trajectories were used to identify the sources of precipitation pollutants. RESULTS: Low pH and high concentrations of ionic and trace species were measured at both sites. Inter-correlations for the simultaneous samples at the two sites were poor for trace elements (−0.07~0.47). A several fold increase in major ion (122~546%) and trace element (261~3,302%) concentrations occurred as the rain fell. Approximately 89% of the air masses responsible for the summit precipitation events were of distance origin. Marine salt, crustal material, fossil fuel burning plus secondary products, and metallic-industry-related factors were identified by PMF, contributing 9.7%, 22.8%, 41.8%, and 25.6%, respectively, to the precipitation pollutants at the summit and 13.3%, 31.9%, 39.6%, and 15.2%, respectively, at the base. CONCLUSIONS: Long-range atmospheric transport primarily influenced the high and the low site precipitation was strongly influenced by the under-cloud scavenging process of local boundary layer pollutants. Crustal material and fossil fuel burning plus secondary products were the predominant pollution sources in this region.
Показать больше [+] Меньше [-]Exposure reduction of seed treatments through dehusking behaviour of the wood mouse (Apodemus sylvaticus)
2011
Brühl, Carsten Albrecht | Guckenmus, Bernd | Ebeling, Markus | Barfknecht, Ralf
BACKGROUND, AIM AND SCOPE: Seed treatments are widely used on cereals and other annual crops throughout Europe. Most of the formulated pesticide is found on the outside of the seed, the husk. Risk assessments of seed treatments are especially needed for granivorous mice living in the agricultural landscape e.g. for registration using the guidance for risk assessment for birds and mammals (EFSA 2009). The dehusking of seeds before consumption is a known behaviour of these mammals, but so far, no quantitative data on the reduction of exposure of seed treatments by dehusking were published. Therefore, we aimed at providing a first quantitative estimate of this behaviour-related exposure reduction for the wood mouse (Apodemus sylvaticus) with different seed types. MATERIALS AND METHODS: We evaluated the efficiency of dehusking behaviour of 20 wood mice captured in the wild for four different seeds (wheat, barley, maize and sunflower). One experimental setup used a fungicide seed treatment where the remaining seed husks of consumed seeds were analysed with a HPLC-MS/MS technique. In the second setup, we measured generic pigment present in a blank seed treatment formulation and determined the leftover pigment in the husks with a photometric technique. RESULTS: The exposure reduction was similar for the fungicide and the pigment design where the same seed types were studied. We could demonstrate exposure reductions ranging from around 60% for cereals to almost 100% for sunflower seeds as a result of the dehusking behaviour. DISCUSSION: Since exposure reduction was similar in both approaches, working with pigments would be a generic way to estimate the impact of dehusking behaviour on seed treatment exposure. This behaviour can result in a substantial exposure reduction and should, therefore, be considered in a seed-type specific way in the risk assessment of pesticide seed treatments. CONCLUSIONS: It is proposed to include a seed-specific dehusking factor in the calculations of estimated theoretical exposure of seed treatments for granivorous mice. The approach of accounting for a dehusking-related exposure reduction by field relevant wild mammal species seems a more promising way to advance the risk assessment instead of using generic species and neglecting behavioural traits. The pigment approach could be used to gather data for exposure reduction for other species and seed types. Its advantage is that it is harmless to the test species and comparatively cheap since no chemical analysis is involved. RECOMMENDATIONS AND PERSPECTIVES: Seed treatments are used for most of the cereal crops grown in Europe today. Their advantages usually include a lower application rate and the reduction of drift compared to a conventional spraying regime. However, there is a potential risk especially for granivorous mice, and its assessment is challenging in case of a high residue concentration on the dressed seeds. The concept of a dehusking factor in the risk assessment scheme for seed treatments for granivorous mice is a valid approach to account for the behavioural exposure reduction, and generic data could be easily generated also for other wild mammal species and other seed types, possibly analysing the pigment in commercial seed treatment formulations.
Показать больше [+] Меньше [-]Effect of nuclear power on CO₂ emission from power plant sector in Iran
2011
Kargari, Nargess | Mastouri, Reza
INTRODUCTION: It is predicted that demand for electricity in Islamic Republic of Iran will continue to increase dramatically in the future due to the rapid pace of economic development leading to construction of new power plants. At the present time, most of electricity is generated by burning fossil fuels which result in emission of great deal of pollutants and greenhouse gases (GHG) such as SO₂, NOₓ, and CO₂. The power industry is the largest contributor to these emissions. Due to minimal emission of GHG by renewable and nuclear power plants, they are most suitable replacements for the fossil-fueled power plants. However, the nuclear power plants are more suitable than renewable power plants in providing baseload electricity. The Bushehr Nuclear Power Plant, the only nuclear power plant of Iran, is expected to start operation in 2010. This paper attempts to interpret the role of Bushehr nuclear power plant (BNPP) in CO₂ emission trend of power plant sector in Iran. MATERIALS AND METHODS: In order to calculate CO₂ emissions from power plants, National CO₂ coefficients have been used. The National CO₂ emission coefficients are according to different fuels (natural gas, fuels gas, fuel oil). RESULTS AND DISCUSSION: By operating Bushehr Nuclear Power Plant in 2010, nominal capacity of electricity generation in Iran will increase by about 1,000 MW, which increases the electricity generation by almost 7,000 MWh/year (it is calculated according to availability factor and nominal capacity of BNPP). CONCLUSIONS: Bushehr Nuclear Power Plant will decrease the CO₂ emission in Iran power sector, by about 3% in 2010.
Показать больше [+] Меньше [-]Characterization of dioxin-like contamination in soil and sediments from the “hot spot” area of petrochemical plant in Pancevo (Serbia)
2011
Kaisarevic, Sonja | Hilscherova, Klara | Weber, Roland | Sundqvist, Kristina L. | Tysklind, Mats | Voncina, Ernest | Bobic, Stanka | Andric, Nebojsa | Pogrmic-Majkic, Kristina | Vojinović-Miloradov, Mirjana | Giesy, John Paul | Kovačević, Radmila
Purpose Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions. Materials and methods Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE-luciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples. Results Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0 × 10⁵ ng/g d.w. of seven-key PCBs, 8.2 ng/g d.w. of PCDD/Fs, and 3.0 × 10⁵ ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2-8 ng/g d.w. of PCDD/Fs and 9-20 ng/g d.w. of PCBs. Conclusions This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production.
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