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Результаты 2031-2040 из 4,042
A Review Study on Past 40 Years of Research on Effects of Tropospheric O3 on Belowground Structure, Functioning, and Processes of Trees: a Linkage with Potential Ecological Implications Полный текст
2016
Agathokleous, Eugenios | Saitanis, Costas J. | Wang, Xiaona | Watanabe, Makoto | Koike, Takayoshi
Woody plants constitute a great sink of carbon storage, mitigating thus the greenhouse effect phenomenon. They are considered key players in ecosystems, and among others, they help in decreasing soil erosion and in maintaining soil moisture. Over the last decades, researches have shown negative effects of the ambient ozone (O₃) on many woody species, not only on canopy but also on belowground part of trees. Negative effects of elevated O₃ (eO₃), which usually refers to any O₃ dosages above the current ambient levels, on belowground structure, function, and processes may have consequences to ecosystem sustainability. We reviewed reports of research published over the past 40 years and dealing with woodies belowground response to eO₃. eO₃ induces changes in C dynamics into plants and alterations in their metabolism accordingly, as a result of different strategies followed by the trees in order to compensate with eO₃ stress effects. In these strategies, phenolics seem to have a detrimental role in shoot/root allometry. Root and soil chemical composition can be also influenced, threatening thus the soil biodiversity, soil fertility, and nutrient cycling. Elevated O₃ impact is discussed with linkage to other potential ecological consequences.
Показать больше [+] Меньше [-]Effects of Mediators for Ligninolytic Enzyme Production and Kinetic Studies on Degradation of Pentachlorobenzene by Trametes versicolor U80 Полный текст
2016
Sari, Ajeng Arum | Yasin, Hasbi | Tachibana, Sanro | Hadibarata, Tony
Pentachlorobenzene is one new persistent organic pollutants (POPs) that has been recently added to the Stockholm Convention on Persistent Organic Pollutants. Based on this reason, one treatment having ability to degrade this compound is needed. The microbiological process by using white-rot fungus was used in this experiment. Free cell of Trametes versicolor U80 degraded pentachlorobenzene 43 % in liquid medium at 40 days incubation. The rapid initial uptake of pentachlorobenzene was obtained in the first 20 days. The results based on ionization potential and the partial least square function indicated that both enzymatic systems of lignin peroxidase and P-450 monooxygenase involved in the degradation of pentachlorobenzene. By using addition of Tween 80, MnSO₄, and veratryl alcohol, degradation of pentachlorobenzene could be improved. Based on kinetic study, the use of 1 % of Tween 80 showed the highest degradation rate (2.0619/day) and the degradation of pentachlorobenzene by 50 % can be shortened up to 24 days. Application of T. versicolor U80 in soil and bioreactor degraded pentachlorobenzene 43 and 50 % at 40 days, respectively. T. versicolor U80 shows good capability degrading pentachlorobenzene in soil and bioreactor although it is lower than in liquid due to the difference of pollutant accessibility and transfer oxygen. Finally, strain T. versicolor U80 can be proposed as an excellent candidate for remediation application in pentachlorobenzene pollution.
Показать больше [+] Меньше [-]Degradation of Rhodamine B by the α-MnO2/Peroxymonosulfate System Полный текст
2016
Liu, Chaonan | Pan, Dongyu | Tang, Xiaoyan | Hou, Meifang | Zhou, Qi | Zhou, Jian
Rhodamine B (RhB) is one of synthetic dyes with good stability. Treatment of wastewater containing synthetic dyes has attracted much attention. Heterogeneous activation of peroxymonosulfate (PMS) has been found to be a promising wastewater treatment technology through the activation with metal oxides for the generation of sulfate radicals. In this study, α-MnO₂ was prepared by a simple hydrothermal method and used as the catalyst to activate PMS. The degradation of RhB was studied by the α-MnO₂/PMS system. It was found that the prepared α-MnO₂ exhibited high catalytic activity on the activation of PMS for the degradation of RhB. The degradation of RhB could be well described by the first-order kinetic model. Influences of PMS concentration and α-MnO₂ dose on the degradation of RhB were examined. The chemical oxygen demand (COD) was determined to evaluate the mineralization capability of the α-MnO₂/PMS system. The stability of α-MnO₂ was also investigated through reusability experiments. Quenching tests of radicals were applied to differentiate the contribution of major reactive species for the degradation of RhB by the α-MnO₂/PMS system.
Показать больше [+] Меньше [-]Enhancement and Biological Characteristics Related to Aerobic Biodegradation of Toluene with Co-Existence of Benzene Полный текст
2016
Yoshikawa, Miho | Zhang, Ming | Toyota, Koki
The interaction between different volatile organic compounds (VOCs) is a critical issue associated with bioremediation of co-contaminated sites. Contradictory results have been reported on the effects of co-existence of VOCs on biodegradation of each VOC. These contradictions are thought to be caused by inter-study variability in microbial diversity. To examine the effects of co-existing VOCs on biodegradation of each VOC, a series of biodegradation tests were carried out with a microcosm capable of degrading all three VOCs: dichloromethane (DCM), benzene, and toluene. We added different combinations of the VOCs to the microcosm while monitoring VOC concentration and microbial community diversity. Degradation of DCM and benzene was minimally influenced by co-existence of other VOCs; however, degradation of toluene was dramatically enhanced by the co-existence of benzene. Propioniferax was identified in cultures exposed to benzene alone and cultures simultaneously exposed to benzene, toluene, and DCM. Propioniferax was dominant, but prior to this study, it was not known to degrade benzene, toluene, and DCM. In the cultures exposed to only toluene, Rhodanobacter, Mycobacterium, Bradyrhizobium, and Intrasporangium increased during the biodegradation. The former three bacteria increased more rapidly when benzene and DCM were also included. These results suggest that co-existence of benzene and DCM can enhance the activity of Rhodanobacter, Mycobacterium, and Bradyrhizobium and consequently accelerate the degradation of toluene.
Показать больше [+] Меньше [-]Long-term tobacco plantation induces soil acidification and soil base cation loss Полный текст
2016
Zhang, Yuting | He, Xinhua | Liang, Hong | Zhao, Jian | Zhang, Yueqiang | Xu, Chen | Shi, Xiaojun
Changes in soil exchangeable cations relative to soil acidification are less studied particularly under long-term cash crop plantation. This study investigated soil acidification in an Ali-Periudic Argosols after 10-year (2002–2012) long-term continuous tobacco plantation. Soils were respectively sampled at 1933 and 2143 sites in 2002 and 2012 (also 647 tobacco plants), from seven tobacco plantation counties in the Chongqing Municipal City, southwest China. After 10-year continuous tobacco plantation, a substantial acidification was evidenced by an average decrease of 0.20 soil pH unit with a substantial increase of soil sites toward the acidic status, especially those pH ranging from 4.5 to 5.5, whereas 1.93 kmol H⁺ production ha⁻¹ year⁻¹ was mostly derived from nitrogen (N) fertilizer input and plant N uptake output. After 1 decade, an average decrease of 27.6 % total exchangeable base cations or of 0.20 pH unit occurred in all seven tobacco plantation counties. Meanwhile, for one unit pH decrease, 40.3 and 28.3 mmol base cations kg⁻¹ soil were consumed in 2002 and 2012, respectively. Furthermore, the aboveground tobacco biomass harvest removed 339.23 kg base cations ha⁻¹ year⁻¹ from soil, which was 7.57 times higher than the anions removal, leading to a 12.52 kmol H⁺ production ha⁻¹ year⁻¹ as the main reason inducing soil acidification. Overall, our results showed that long-term tobacco plantation not only stimulated soil acidification but also decreased soil acid-buffering capacity, resulting in negative effects on sustainable soil uses. On the other hand, our results addressed the importance of a continuous monitoring of soil pH changes in tobacco plantation sites, which would enhance our understanding of soil fertility of health in this region.
Показать больше [+] Меньше [-]Radiostrontium monitoring of bivalves from the Pacific coast of eastern Japan [Erratum: December 2021, Vol.28(47), p.67907] Полный текст
2016
Karube, Zin’ichi | Inuzuka, Yoko | Tanaka, Atsushi | Kurishima, Katsuaki | Kihou, Nobuharu | Shibata, Yasuyuki
In early April 2011, radiostrontium was accidentally released from the Fukushima Daiichi Nuclear Power Plant to the Pacific coast of eastern Japan. We developed a simple procedure to analyze radiostrontium levels in marine mussels (Septifer virgatus) and seawater using crown ether (Sr Resin; Eichrom). Then, we used our method to describe the spatial and temporal distribution of radiostrontium in mussels and seawater on the Pacific coast of eastern Japan from 2011 to 2013 and for 2015. Activity of ⁹⁰Sr in mussels and seawater decreased with distance from the Fukushima Daiichi Nuclear Power Plant and between 2011 and 2013 tended to be higher in areas south of the Fukushima Daiichi Nuclear Power Plant than to the north of it. Activity in mussels and seawater also tended to decrease from 2011 to 2013 and by 2015 had reached levels experienced prior to the Fukushima accident. Our results suggest that radiostrontium discharged from the Fukushima Daiichi Nuclear Power Plant was dispersed by coastal currents in a southerly direction along the Pacific coast of eastern Japan from 2011 to 2013, following which its activity decreased to background levels by 2015.
Показать больше [+] Меньше [-]Comparison Between Sorption and Sono-Sorption Efficiencies, Equilibriums and Kinetics in the Uptake of Direct Red 23 from the Aqueous Solutions Полный текст
2016
Oguz, Ensar | Bire, Murat | Nuhoglu, Yasar
Using ZnO nanoparticles, comparisons between sorption and sono-sorption efficiencies, equilibrium and kinetics in Direct Red 23 have been researched under the various experimental conditions. Pseudo-second-order model was practiced for the experimental data. The mechanism of the dye uptake was clarified based on the analyses of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Brunauer-Emmett-Teller (BET) surface area and total pore volume of the nanoparticles were obtained. The highest Direct Red 23 (DR23) removal efficiencies by sorption and sono-sorption processes were determined as 78.6 and 96.8 %, respectively. Experimental data have been evaluated according to Langmuir, Freundlich and Dubinin-Radushkevich. The mean energies of sorption and sono-sorption processes were calculated to be 16.22 and 25.41 kJ/mol, respectively. Arrhenius equation was used to calculate the activation energies. ΔH° and ΔG° values indicated that sorption and sono-sorption processes were endothermic processes. But, negative free energy values of ΔG° indicated that sorption and sono-sorption processes were favoured at high temperatures.
Показать больше [+] Меньше [-]Individual PM2.5 exposure is associated with the impairment of cardiac autonomic modulation in general residents Полный текст
2016
Xie, Yuquan | Bo, Liang | Jiang, Shuo | Tian, Zhenyong | Kan, Haidong | Yigang, | Song, Weimin | Zhao, Jinzhuo
Fine particulate matter (PM₂.₅) is one of the major pollutants in metropolitan areas. The current study was conducted to observe the effects of PM₂.₅ on cardiac autonomic modulation. The participants included 619 men and women aged from 35–75 in a residential area in Shanghai, China. All the participants were divided into four categories according to the distance between their apartments and major road. In addition, individual PM₂.₅ was measured using SIDEPAKTM AM510 (TSI, USA) from 8:00 am to 6:00 pm. At the end of the individual PM₂.₅ measurement, the systolic pressure, diastolic pressure, heart rate (HR), low-frequency (LF), high-frequency (HF), and LF/HF were determined. The association between individual PM₂.₅ level and the above health effects was analyzed using generalized linear regression. The results showed that the average concentration of individual PM₂.₅ was 95.5 and 87.0 μg/m³ for men and women. Residential distance to major road was negatively correlated with the individual PM₂.₅. The results indicated that per 1.0 μg/m³ increase of individual PM₂.₅ was associated with a 2.3 % increase for systolic pressure, 0.3 % increase for diastolic pressure, 0.4 % decrease for LF, and 0.4 % decrease for HF. Nevertheless, there was no statistical association between individual PM₂.₅ and heart rate and LF/HF in the total model. In addition, the similar results were found in men and women excluding a significant association between PM₂.₅ and the heart rate in men. The alterations of cardiac autonomic modulation hinted that PM₂.₅ exposure might be associated with the potential occurrence of cardiovascular disease, such as arrhythmia and ischemic heart diseases.
Показать больше [+] Меньше [-]Αn Investigation of the Biogeochemical Properties of the Plant Species Οriganum majorana in Relation to its Soil Characteristics Полный текст
2016
Sazakli, Eleni | Panagopoulou, Ekaterini | Leotsinidis, Michalis | Kalavrouziotis, Ioannis K. | Varnavas, Soterios P.
A biogeochemical investigation was carried out on Origanum majorana grown on limestone substrate in Greece. Possible health risks from consumption of dried herbs and infusions were assessed. Macronutrients and essential and toxic metals were determined in the leaves of O. majorana plants and in their soil substrates. Toxic metals were measured in the herbal infusions. Macroelements were found generally in low concentrations for normally developing plants, except for Ca. The ratios N/P and N/K were found lower than the optimum range for normal growth, while the values of K/(Ca + Mg) ratio prevent the development of grass tetany. Manganese and arsenic were enriched in distinct samples. O. majorana plants can be used as indicators for soil environmental assessment. They can also be applied in phytoremediation methods in metal-polluted soils. Hazard indices were far below 1. Carcinogenic risks were found to be within the acceptable range. No health risk is anticipated by the consumption of the specific plants investigated in the present study.
Показать больше [+] Меньше [-]Water Quality Impact from the Discharge of Coal Mine Wastes to Receiving Streams: Comparison of Impacts from an Active Mine with a Closed Mine Полный текст
2016
Price, Philip | Wright, Ian A.
This study examined two underground coal mines in the Sydney basin and investigated the water chemistry impact from their wastewater discharges to surface receiving waters. One mine closed 17 years prior to the study, and the other was still active. The geology of both mine locations shared many similarities and some important differences that influenced their wastewater chemistry and its subsequent impact on receiving waterways. Water quality of wastewater discharges from the two mines and their receiving waterways was investigated over a 6-month period. Both mine discharges caused comprehensive modification to receiving water chemistry. The closed mine increased electrical conductivity (EC) 3.3 times from upstream (33 μS/cm) compared to downstream (108 μS/cm). In comparison, the active mine increased EC by 9.4 times (173 μS/cm) upstream to 1628 μS/cm downstream. Both coal mine wastes increased the concentration of different contaminants to levels that are potentially hazardous for receiving water ecosystems. The active mine increased bicarbonate concentration in the receiving water by more than 60 times to 743 mg/L. The closed mine increased zinc and nickel concentrations in its receiving stream by 70 and 20 times to 318 and 360 μg/L. The active coal mine discharge was dominated by sodium and bicarbonate ions compared to magnesium and sulphate ions in the closed mine drainage. Although both receiving waters were sodium and chloride dominated upstream of the mine waste, their ionic composition was strongly modified due to the inflow of coal mine wastes. Results from this study are a reminder that water pollution from coal mines is important for both active mines and for closed mines decades after mining activity ceases.
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