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Does energy consumption contribute to environmental pollutants? evidence from SAARC countries Texte intégral
2014
Akhmat, Ghulam | Zaman, Khalid | Shukui, Tan | Irfan, Danish | Khan, Muhammad Mushtaq
The objective of the study is to examine the causal relationship between energy consumption and environmental pollutants in selected South Asian Association for Regional Cooperation (SAARC) countries, namely, Bangladesh, India, Nepal, Pakistan, and Srilanka, over the period of 1975–2011. The results indicate that energy consumption acts as an important driver to increase environmental pollutants in SAARC countries. Granger causality runs from energy consumption to environmental pollutants, but not vice versa, except carbon dioxide (CO₂) emissions in Nepal where there exists a bidirectional causality between CO₂ and energy consumption. Methane emissions in Bangladesh, Pakistan, and Srilanka and extreme temperature in India and Srilanka do not Granger cause energy consumption via both routes, which holds neutrality hypothesis. Variance decomposition analysis shows that among all the environmental indicators, CO₂ in Bangladesh and Nepal exerts the largest contribution to changes in electric power consumption. Average precipitation in India, methane emissions in Pakistan, and extreme temperature in Srilanka exert the largest contribution.
Afficher plus [+] Moins [-]Release of agronomical nutrient from zeolitite substrate containing phosphatic waste Texte intégral
2014
Lancellotti, I. | Toschi, T. | Passaglia, E. | Barbieri, L.
The principal plant nutrients are phosphorous, nitrogen and potassium. Among these compounds, phosphorous is the most critical: it reacts rapidly, becoming an insoluble compound. The combination of zeolitites with phosphate materials (zeoponic substrate) agrees to a gradual and controlled phosphorous release in soils: phosphorous for plant uptake is released by the combination of dissolution and ion-exchange reactions. Animal bone ashes, rich in phosphorous and leached alone, release little amounts of soluble phosphorous and a great deal of alkaline sodium and potassium. Concerning chabazitic-zeolitite, it encourages a both gradual and growing soluble phosphorous release from animal bone ashes, in accordance with clinoptilolitic- and phillipsitic-zeolitite abilities; in particular, that release increases, thanks to both a higher zeolitite/bone ash ratio and ammonium enrichment of zeolitite. The use of zeolitite is environmentally sustainable in Italy because large amounts of deposits of zeolitite were present in Italy.
Afficher plus [+] Moins [-]Distribution of PCDD/Fs and dioxin-like PCBs in sediment and plants from a contaminated salt marsh (Tejo estuary, Portugal) Texte intégral
2014
Nunes, Margarida | Vernisseau, Anaïs | Marchand, Philippe | Le Bizec, Bruno | Ramos, Fernando | Pardal, Miguel A.
Concentrations and profiles of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were investigated in sediment and plants collected from a salt marsh in the Tejo estuary, Portugal. The highest PCDD/F and dl-PCB concentrations were detected in uncolonized sediments, averaging 325.25 ± 57.55 pg g⁻¹dry weight (dw) and 8,146.33 ± 2,142.14 pg g⁻¹dw, respectively. The plants Sarcocornia perennis and Halimione portulacoides growing in PCDD/F and dl-PCB contaminated sediments accumulated contaminants in roots, stems, and leaves. It was observed that PCDD/F and dl-PCB concentrations in roots were significantly lower in comparison with stems and leaves. In general, concentration of ΣPCDD/Fs and Σdl-PCBs in H. portulacoides tissues were found to be twofold higher than those in S. perennis, indicating a difference in the accumulation capability of both species. Furthermore, congener profiles changed between sediments and plant tissues, reflecting a selective accumulation of low chlorinated PCDD/Fs and non-ortho dl-PCBs in plants.
Afficher plus [+] Moins [-]Energy-dependent uptake of benzo[a]pyrene and its cytoskeleton-dependent intracellular transport by the telluric fungus Fusarium solani Texte intégral
2014
Fayeulle, Antoine | Veignie, Etienne | Slomianny, Christian | Dewailly, Etienne | Munch, Jean Charles | Rafin, Catherine
In screening indigenous soil filamentous fungi for polycyclic aromatic hydrocarbons (PAHs) degradation, an isolate of the Fusarium solani was found to incorporate benzo[a]pyrene (BaP) into fungal hyphae before degradation and mineralization. The mechanisms involved in BaP uptake and intracellular transport remain unresolved. To address this, the incorporation of two PAHs, BaP, and phenanthrene (PHE) were studied in this fungus. The fungus incorporated more BaP into cells than PHE, despite the 400-fold higher aqueous solubility of PHE compared with BaP, indicating that PAH incorporation is not based on a simple diffusion mechanism. To identify the mechanism of BaP incorporation and transport, microscopic studies were undertaken with the fluorescence probes Congo Red, BODIPY®493/503, and FM®4-64, targeting different cell compartments respectively fungal cell walls, lipids, and endocytosis. The metabolic inhibitor sodium azide at 100 mM totally blocked BaP incorporation into fungal cells indicating an energy-requirement for PAH uptake into the mycelium. Cytochalasins also inhibited BaP uptake by the fungus and probably its intracellular transport into fungal hyphae. The perfect co-localization of BaP and BODIPY reveals that lipid bodies constitute the intracellular storage sites of BaP in F. solani. Our results demonstrate an energy-dependent uptake of BaP and its cytoskeleton-dependent intracellular transport by F. solani.
Afficher plus [+] Moins [-]Assessing the effects of heavy metal contamination on the proteome of the moss Pseudoscleropodium purum cross-transplanted between different areas Texte intégral
2014
Boquete, M Teresa | Bermúdez-Crespo, José | Aboal, Jesús R. | Carballeira, Alejo | Fernández, J Ángel
Protein expression was assessed in samples of Pseudoscleropodium purum cross-transplanted between one unpolluted (UNP) and two polluted (POLL) sites. Firstly, the level of expression (LE) of 17 proteins differed between native mosses from both types of sites, but differences were only maintained throughout the experiment for 5 of them. The LE of these five proteins changed over time in mosses transplanted from UNP to POLL and vice versa, becoming similar to that in autotransplants. However, these changes occurred slower than changes in the heavy metal concentrations measured in the same samples, and therefore they were not related to atmospheric pollution. Although the proteins identified were associated with moss metabolism, the expected growth reduction in samples autotransplanted within POLL (as a result of the down-regulation of photosynthesis-related proteins), did not occur. This supports the hypothesis that mosses growing in polluted areas adapt to heavy metal pollution and are able to reduce/overcome their toxic effects (i.e., reduced growth). Nevertheless, further specific research must be carried out to identify the proteins involved in this type of response, as lack of information on the bryophyte genome precludes us from reaching further conclusions.
Afficher plus [+] Moins [-]Assessing the enrichment of heavy metals in surface soil and plant (Digitaria eriantha) around coal-fired power plants in South Africa Texte intégral
2014
Okedeyi, Olumuyiwa O. | Dube, Simiso | Awofolu, Omotayo R. | Nindi, Mathew M.
Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr, and Zn) were determined in soil and Digitaria eriantha plants within the vicinity of three coal power plants (Matla, Lethabo, and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1836 ± 70 μg g⁻¹, 0.08 ± 0.05 to 1744 ± 29 μg g⁻¹, and 0.07 ± 0.04 to 1735 ± 91 μg g⁻¹in Matla, Lethabo, and Rooiwal, respectively. Total metal concentration in the plant (D. eriantha) ranged from 0.005 ± 0.003 to 535 ± 43 μg g⁻¹in Matla, 0.002 ± 0.001 to 400 ± 269 μg g⁻¹in Lethabo, and 0.002 ± 0.001 to 4277 ± 201 μg g⁻¹in Rooiwal. Accumulation factors (A) of less than 1 (i.e., 0.003 to 0.37) at all power plants indicate a low transfer of metal from soil to plant (excluder). Enrichment factor values obtained (2.4–5.0) indicate that the soils are moderately enriched with the exception of Pb that had significant enrichment of 20. Geo-accumulation index (I-geo) values of metals indicate that the soils are moderately polluted (0.005–0.65), except for Pb that showed moderate to strong pollution (1.74–2.53).
Afficher plus [+] Moins [-]Leachates from solid wastes: chemical and eco(geno)toxicological differences between leachates obtained from fresh and stabilized industrial organic sludge Texte intégral
2014
Chiochetta, Claudete G. | Goetten, Luís C. | Almeida, Sônia M. | Quaranta, Gaetana | Cotelle, Sylvie | Radetski, Claudemir M.
The chemical and ecotoxicological characteristics of fresh and stabilized industrial organic sludge leachates were compared to obtain information regarding how the stabilization process can influence the ecotoxic potential of this industrial waste, which could be used for the amendment of degraded soil. Physicochemical analysis of the sludge leachates, as well as a battery of eco(geno)toxicity tests on bacteria, algae, daphnids, and higher plants (including Vicia faba genotoxicity test) and the determination of hydrolytic enzyme activity, was performed according to standard methods. The chemical comparison of the two types of leachate showed that the samples obtained from stabilized sludge had a lower organic content and higher metal content than leachates of the fresh sludge. The eco(geno)toxicological results obtained with aquatic organisms showed that the stabilized sludge leachate was more toxic than the fresh sludge leachate, both originating from the same industrial organic sludge sample. Nevertheless, phytotoxicity tests carried out with a reference peat soil irrigated with stabilized sludge leachate showed the same toxicity as the fresh sludge leachate. In the case of the industrial solid organic sludge studied, stabilization through a biodegradation process promoted a higher metal mobility/bioavailability/eco(geno)toxicity in the stabilized sludge leachate compared to the fresh sludge leachate.
Afficher plus [+] Moins [-]Carbon emission from global hydroelectric reservoirs revisited Texte intégral
2014
Li, Siyue | Zhang, Quanfa
Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO₂)/year and 18.7 Tg methane (CH₄)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO₂and 67 % CH₄of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO₂/kWh and 5.7 g CH₄/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO₂eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.
Afficher plus [+] Moins [-]Temporal and spatial variations in the relationship between urbanization and water quality Texte intégral
2014
Ren, Lijun | Cui, Erqian | Sun, Haoyu
With the development of economy, most of Chinese cities are at the stage of rapid urbanization in recent years, which has caused many environmental problems, especially the serious deterioration of water quality. Therefore, the research of the relationship between urbanization and water quality has important theoretical and practical significance, and it is also the main restriction factor in the urbanization advancement. In this work, we investigated the impact of urbanization on the water quality of the nearby river. We established a comprehensive environmental assessment framework by combining urbanization and water quality, and one model was designed to examine the impact of urbanization on the water quality in Jinan from 2001 to 2010 with factor component analysis. The assessment of urbanization level was accomplished using a comprehensive index system, which was based on four aspects: demographic urbanization, economic urbanization, land urbanization, and social urbanization. In addition, synthetic pollution index method was utilized to assess the water pollution of Xiaoqing River in the study area. Through the analysis of regression curves, we conclude that (1) when the urbanization level is below 25 %, the relationship is low and irregular; (2) if the urbanization level varies between 25 and 40 %, there will be an irreversible degradation of stream water quality; (3) there is a positive correlation between urbanization and pollution levels of urban river after the adjustment period; and (4) land and demographic aspects have the highest independent contribution. This study is a useful reference for policymakers in terms of economic and environmental management.
Afficher plus [+] Moins [-]Assessment of heavy metal and organic contaminants levels along the Libyan coast using transplanted mussels (Mytilus galloprovincialis) Texte intégral
2014
Galgani, François | Chiffoleau, Jean-François | Barrah, Mahmoud | Drebika, Usama | Tomasino, Corinne | Andral, Bruno
Within the framework of the MYTIOR project in 2009, heavy metals and organic compounds contaminations were assessed in transplanted mussels in 16 different stations along the coasts of Libya. These stations were located at miles offshore industrial/urban sources but in open sea providing original results related to the background contamination rather than linked to a specific coastal source of pollutants. Results indicated mercury (Hg, 0.045–0.066 mg/kg dry weight (dw)), lead (Pb, 0.44–0, 71 mg/kg dw) and copper (Cu, 3.56–4.21 mg/kg dw) were in the same range or at lower value than control for all stations. Chromium (Cr) in Meleta (3.08 mg/kg dw) and Bomba (3.80 mg/kg dw) and Cadmium values in all stations (1.21–2.41 mg/kg dw) were above control. Meleta, stations from the gulf of Syrt and the three eastern stations were the most affected stations by nickel (max at 5.83 mg/kg dw in Syrt) when zinc was in the same range (141–197 mg/kg dw) and above the control (92 mg/kg dw) at all stations. Polycyclic aromatic hydrocarbon (PAH) levels were found in the range of 16.8–42.8 mg/kg (dry weight) indicating low levels along the Libyan coast with acenaphthene and benzo (a, b, k) pyrenes detected mainly in western Libya. The study of PAH ratios indicated a mixed petrogenic/pyrolytic origin. The only polychlorinated biphenyls (PCBs) found in Libya were PCB 101 in one location and PCB 153 in Tripoli, Garrapoli, Syrt, Ras Lanuf and Benghazi (1.2–1.9 μg/kg dw). Insecticides were lower than control in all stations except DDT, only detected in Misratah (3.5 μg/kg dw). Overall, the results indicated a low background contamination and a low pollution extent according to the environmental pressure occurring offshore the Libyan coast.
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