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Antimony (SbIII) reduces growth, declines photosynthesis, and modifies leaf tissue anatomy in sunflower (Helianthus annuus L.) Texte intégral
2015
Vaculík, Marek | Mrázová, Anna | Lux, Alexander
The role of antimony (Sb)—a non-essential trace metalloid—in physiological processes running in crops is still poorly understood. Present paper describes the effect of Sb tartrate (SbIII) on growth, Sb uptake, photosynthesis, photosynthetic pigments, and leaf tissue organization in young sunflower plants grown in hydroponics. We found that growth of below- and aboveground part was reduced with increasing concentration of Sb in the medium. Although Sb was mostly taken up by sunflower roots and only small part (1–2 %) was translocated to the shoots, decline in photosynthesis, transpiration, and decreased content of photosynthetic pigments were observed. This indicates that despite relatively low mobility of Sb in root-shoot system, Sb in shoot noticeably modifies physiological status and reduced plant growth. Additionally, leaf anatomical changes indicated that Sb reduced the size of intercellular spaces and made leaf tissue more compact.
Afficher plus [+] Moins [-]Effluent characteristics of advanced treatment for biotreated coking wastewater by electrochemical technology using BDD anodes Texte intégral
2015
Wang, Chunrong | Zhang, Mengru | Liu, Wei | Ye, Min | Su, Fujin
Effluent of biotreated coking wastewater comprises hundreds of organic and inorganic pollutants and has the characteristics of high toxicity and difficult biodegradation; thus, its chemical oxygen demand cannot meet drainage standards in China. A boron-doped diamond anode was selected for advanced treatment of biotreated coking wastewater, and considering the efficiency of the removal of total organic carbon and energy consumption, optimal conditions were obtained as current density of 75 mA cm⁻², electrolysis time of 1.5 h, and an electrode gap of 1.0 cm in an orthogonal test. Effluent characteristics were investigated at different electrolysis times. The ratio of the 5-day biochemical oxygen demand (BOD₅) to the chemical oxygen demand increased from an initial value of 0.05 to 0.65 at 90 min. Fluorescence spectra were used to evaluate the evolution of refractory organics. Two fluorescence peaks for raw wastewater, corresponding to an aromatic protein-like substance II and humic acid-like substance, weakened at 30 and at 90 min, only the former was detected. The specific oxygen uptake rate was used to assess effluent toxicity, and an obvious inhibition effect was found at 15 min; then, it was significantly faded at 30 and 45 min. The BOD₅/NO₃⁻-N ratio increased from an initial value of 0.48 to 1.25 at 45 min and then gradually dropped to 0.69 at 90 min. According to the above effluent characteristics, it is strongly suggested that electrochemical technology using boron-doped diamond anodes is combined with biological denitrification technology for the advanced treatment of biotreated coking wastewater.
Afficher plus [+] Moins [-]Effect of biochar amendment on yield and photosynthesis of peanut on two types of soils Texte intégral
2015
Xu, Cheng-Yuan | Hosseini-Bai, Shahla | Hao, Yanbin | Rachaputi, Rao C. N. | Wang, Hailong | Xu, Zhihong | Wallace, Helen
Biochar has significant potential to improve crop performance. This study examined the effect of biochar application on the photosynthesis and yield of peanut crop grown on two soil types. The commercial peanut cultivar Middleton was grown on red ferrosol and redoxi-hydrosol (Queensland, Australia) amended with a peanut shell biochar gradient (0, 0.375, 0.750, 1.50, 3.00 and 6.00 %, w/w, equivalent up to 85 t ha⁻¹) in a glasshouse pot experiment. Biomass and pod yield, photosynthesis-[CO₂] response parameters, leaf characteristics and soil properties (carbon, nitrogen (N) and nutrients) were quantified. Biochar significantly improved peanut biomass and pod yield up to 2- and 3-folds respectively in red ferrosol and redoxi-hydrosol. A modest (but significant) biochar-induced improvement of the maximum electron transport rate and saturating photosynthetic rate was observed for red ferrosol. This response was correlated to increased leaf N and accompanied with improved soil available N and biological N fixation. Biochar application also improved the availability of other soil nutrients, which appeared critical in improving peanut performance, especially on infertile redoxi-hydrosol. Our study suggests that application of peanut shell derived biochar has strong potential to improve peanut yield on red ferrosol and redoxi-hydrosol. Biochar soil amendment can affect leaf N status and photosynthesis, but the effect varied with soil type.
Afficher plus [+] Moins [-]Source analysis of global anthropogenic lead emissions: their quantities and species Texte intégral
2015
Liang, Jing | Mao, Jiansu
Lead emissions originate primarily from the anthropogenic lead cycle, and research into their characteristics, such as species type, provides essential information for pollution control. A dynamic model for global lead emissions has been established, and their emissions and temporal accumulations were estimated in this study based on the evolution of the lead cycle over 70 years. An inventory of the emissions species was obtained after identifying their physiochemical transformations. The 2010 emissions were 3.56 Mt, with 65 % coming from waste management and recycling. The main species were PbSO₄(42.5 %), PbO₂(16.2 %), and PbS (8.3 %). Between 1930 and 2010, the total lead emissions were 173.8 Mt, mainly from waste management and recycling (48 %), production (26 %), and use (20 %). The main species were PbSO₄, PbO, Pb, and PbS, and together, they accounted for 61.2 % of the total emissions. Over time, species, such as tetraethyl lead and Pb, declined, but PbO₂and PbSO₄increased.
Afficher plus [+] Moins [-]One-year intensive characterization on PM2.5 nearby port area of Thessaloniki, Greece Texte intégral
2015
Tolis, Evangelos I. | Saraga, Dikaia E. | Filiou, Katerina F. | Tziavos, Nikolaos I. | Tsiaousis, Chistos P. | Dinas, Athanasios | Bartzis, John G.
The chemical characterization of particulate matter (PM) 2.5 fraction was studied during a 1-year sampling campaign conducted at a site near Thessaloniki’s port area. PM2.5 collected samples were chemically analyzed for polycyclic aromatic hydrocarbons, minerals, and trace elements (Pb, Ni, Cu, V, Mn, Cr, Zn, Mg, K, Ti, Fe, Ca, and Al); water-soluble ions (Cl⁻, NO₃⁻, SO₄²⁻, K⁺, Na⁺, NH₄⁺, Mg²⁺, Ca²⁺); and organic and elemental carbon. The average annual PM2.5 concentration (66.0 μg/m³) was at the highest level compared with other studies reported for the same city but different sampling sites. The average daily sum of the measured concentration of polycyclic aromatic hydrocarbons (PAHs) was 12.76 ng/m³; this value decreased to 6.73 ng/m³for the warm period and reached the value of 19.8 ng/m³for the cold period. The average concentration of benzo[a]pyrene during the sampling period was 0.75 ng/m³, which is below the European Union limit value of 1.0 ng/m³. The ionic content comprised, on average, 22.6 % of the PM2.5 mass, with sulfate and ammonium being the most abundant species (31 and 26 %, respectively, of measured ions during the whole sampling period). The annual mean concentrations of organic carbon (OC) and elemental carbon (EC) were 10.5 ± 6.3 and 2.3 ± 1.5 μg/m³, respectively. The OC/EC ratio ranged from 1.6 to 9.9, suggesting that there is a significant influence of residential wood burning for heating as well as ship and vehicle emissions to the sampling area. Finally, the elemental composition of associated PM2.5 was dominated by Ca, Fe, and Al. Although conclusions based only on PM2.5 measurements cannot entirely estimate all harbor sources’ contribution, there is evidence to support that port activities affect the city’s air quality and vice versa.
Afficher plus [+] Moins [-]Polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polycyclic aromatic hydrocarbons around a thermal desorption plant in China Texte intégral
2015
Liu, Jie | Li, Xiaodong | Chen, Tong | Qi, Zhifu | Buekens, Alfons | Lu, Shengyong | Yan, Jianhua
This study was launched to establish comprehensive environmental monitoring on the levels and patterns of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polycyclic aromatic hydrocarbons (PAHs) both in soil and ambient air around a thermal desorption plant in China. All 209 congeners of PCBs, 136 congeners of PCDD/Fs (P = 4 to 8) and 16 EPA priority PAHs were analyzed. The concentration of PCBs ranged from 20.0 to 536 ng g⁻¹(or 0.077–5.27 pg WHO-TEQ g⁻¹) in soil and from 972 to 991 ng Nm⁻³(or 0.245–0.374 pg WHO-TEQ Nm⁻³) in air samples, much higher than the levels in cities. A single soil sampling point could have been affected by some transfer of PCBs from the untreated soil by the fingerprint characteristics and the statistical analysis. Establishing blank values prior to the start-up of new plant is a safe and sure method to establish subsequent impacts on the environment. During the treatment of hazardous waste, strict control of all waste materials and all emissions is required.
Afficher plus [+] Moins [-]The impact of biochars on sorption and biodegradation of polycyclic aromatic hydrocarbons in soils—a review Texte intégral
2015
Anyika, Chinedum | Abdul Majid, Zaiton | Ibrahim, Zahara | Zakaria, Mohamad Pauzi | Yahya, Adibah
Amending polycyclic aromatic hydrocarbon (PAH)-contaminated soils with biochar may be cheaper and environmentally friendly than other forms of organic materials. This has led to numerous studies on the use of biochar to either bind or stimulate the microbial degradation of organic compounds in soils. However, very little or no attention have been paid to the fact that biochars can give simultaneous impact on PAH fate processes, such as volatilization, sorption and biodegradation. In this review, we raised and considered the following questions: How does biochar affect microbes and microbial activities in the soil? What are the effects of adding biochar on sorption of PAHs? What are the effects of adding biochar on degradation of PAHs? What are the factors that we can manipulate in the laboratory to enhance the capability of biochars to degrade PAHs? A triphasic concept of how biochar can give simultaneous impact on PAH fate processes in soils was proposed, which involves rapid PAH sorption into biochar, subsequent desorption and modification of soil physicochemical properties by biochar, which in turn stimulates microbial degradation of the desorbed PAHs. It is anticipated that biochar can give simultaneous impact on PAH fate processes in soils.
Afficher plus [+] Moins [-]Air and seawater pollution and air–sea gas exchange of persistent toxic substances in the Aegean Sea: spatial trends of PAHs, PCBs, OCPs and PBDEs Texte intégral
2015
Lammel, Gerhard | Audy, Ondřej | Besis, Athanasios | Efstathiou, Christos | Eleftheriadis, Kostas | Kohoutek, Jiří | Kukučka, Petr | Mulder, Marie D. | Přibylová, Petra | Prokeš, Roman | Rusina, Tatsiana P. | Samara, Constantini | Sofuoglu, Aysun | Sofuoglu, Sait C. | Taşdemir, Yücel | Vassilatou, Vassiliki | Voutsa, Dimitra | Vrana, Branislav
Near-ground air (26 substances) and surface seawater (55 substances) concentrations of persistent toxic substances (PTS) were determined in July 2012 in a coordinated and coherent way around the Aegean Sea based on passive air (10 sites in 5 areas) and water (4 sites in 2 areas) sampling. The direction of air–sea exchange was determined for 18 PTS. Identical samplers were deployed at all sites and were analysed at one laboratory. hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs) as well as dichlorodiphenyltrichloroethane (DDT) and its degradation products are evenly distributed in the air of the whole region. Air concentrations of p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and o,p′-DDT and seawater concentrations of p,p′-DDE and p,p′-DDD were elevated in Thermaikos Gulf, northwestern Aegean Sea. The polychlorinated biphenyl (PCB) congener pattern in air is identical throughout the region, while polybrominated diphenylether (PBDE)patterns are obviously dissimilar between Greece and Turkey. Various pollutants, polycyclic aromatic hydrocarbons (PAHs), PCBs, DDE, and penta- and hexachlorobenzene are found close to phase equilibrium or net-volatilisational (upward flux), similarly at a remote site (on Crete) and in the more polluted Thermaikos Gulf. The results suggest that effective passive air sampling volumes may not be representative across sites when PAHs significantly partitioning to the particulate phase are included.
Afficher plus [+] Moins [-]Calcium affecting protein expression in longan under simulated acid rain stress Texte intégral
2015
Pan, Tengfei | Li, Yongyu | Ma, Cuilan | Qiu, Dongliang
Longan (Dimocarpus longana Lour. cv. Wulongling) of uniform one-aged seedlings grown in pots were selected to study specific proteins expressed in leaves under simulated acid rain (SiAR) stress and exogenous Ca²⁺ regulation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results showed that there was a protein band specifically expressed under SiAR of pH 2.5 stress for 15 days with its molecular weight of about 23 kD. A 17 kD protein band specifically expressed after SiAR stress 5 days. Compared with pH 2.5, the pH 3.5 of SiAR made a less influence to protein expression. Two-dimensional electrophoresis (2-DE) results showed that six new specific proteins including C₄ (20.2 kD pI 6.0), F (24 kD pI 6.35), B₃ (22.3 kD pI 6.35), B₄ (23.5 kD pI 6.5), C₅ (21.8 kD pI 5.6), and C₆ (20.2 kD pI 5.6) specifically expressed. C₄ always expressed during SiAR stress. F expressed under the stress of pH 2.5 for 15 days and expressed in all pH SiAR stress for 20 days. The expression of proteins including B₃, C₅, and C₆ was related to pH value and stress intensity of SiAR. The expression of B₄ resulted from synergistic effects of SiAR and Ca. The expression of G₁ (Mr 19.3 kD, pI 4.5), G₂ (Mr 17.8 kD, pI 4.65), G₃ (Mr 16.6 kD, pI 4.6), and G₄ (Mr 14.7 kD, pI 4.4) enhanced under the treatment of 5 mM ethylene glycol tetraacetic acid (EGTA) and 2 mM chlorpromazine (CPZ). These proteins showed antagonistic effects and might be relative to the Ca-calmodulin (Ca-CaM) system of longan in response to SiAR stress.
Afficher plus [+] Moins [-]The diverse toxic effect of SiO2 and TiO2 nanoparticles toward the marine microalgae Dunaliella tertiolecta Texte intégral
2015
Manzo, S. | Buono, S. | Rametta, G. | Miglietta, M. | Schiavo, S. | Di Francia, G.
Nanoparticles (NPs) are widely used in many industrial applications. NP fate and behavior in seawater are a very important issue for the assessment of their environmental impact and potential toxicity. In this study, the toxic effects of two nanomaterials, silicon dioxide (SiO₂) and titanium dioxide (TiO₂) NPs with similar primary size (~20 nm), on marine microalgae Dunaliella tertiolecta were investigated and compared. The dispersion behavior of SiO₂ and TiO₂ NPs in seawater matrix was investigated together with the relative trend of the exposed algal population growth. SiO₂ aggregates rapidly reached a constant size (600 nm) irrespective of the concentration while TiO₂ NP aggregates grew up to 4 ± 5 μm. The dose–response curve and population growth rate alteration of marine alga D. tertiolecta were evaluated showing that the algal population was clearly affected by the presence of TiO₂ NPs. These particles showed effects on 50 % of the population at 24.10 [19.38–25.43] mg L⁻¹ (EC50) and a no observed effect concentration (NOEC) at 7.5 mg L⁻¹. The 1 % effect concentration (EC1) value was nearly above the actual estimated environmental concentration in the aquatic environment. SiO₂ NPs were less toxic than TiO₂ for D. tertiolecta, with EC50 and NOEC values one order of magnitude higher. The overall toxic action seemed due to the contact between aggregates and cell surfaces, but while for SiO₂ a direct action upon membrane integrity could be observed after the third day of exposure, TiO₂ seemed to exert its toxic action in the first hours of exposure, mostly via cell entrapment and agglomeration.
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