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Estimation of changes in fitness components and antioxidant defense of Drosophila subobscura (Insecta, Diptera) after exposure to 2.4 T strong static magnetic field
2015
Todorović, Dajana | Perić-Mataruga, Vesna | Mirčić, Dejan | Ristić-Djurović, Jasna | Prolić, Zlatko | Petković, Branka | Savić, Tatjana
As an ecological factor, a magnetic field can affect insects causing a wide range of responses. The main purpose of this study was to analyze the fitness components (postembryonic development and viability of individuals) and the antioxidant defense (superoxide dismutase, catalase, and total glutathione) in laboratory strains of Drosophila subobscura, originating from oak and beech forests after exposure to the strong static magnet (2.4 T, VINCY Cyclotron magnet). The first instar larvae were placed near the north pole (N group) or the south pole (S group) of the magnet for 2 h. Oak and beech populations of D. subobscura had longer development time and lower viability in N and S groups compared to controls. These differences were significant only in S group of oak population and in N group of beech population. Total glutathione content was significantly decreased in both exposed groups of oak population, while catalase activity was significantly increased in both exposed groups of beech population. Being significantly decreased in both exposed groups of oak population and significantly increased in S group of beech population in comparison to controls, superoxide dismutase activity was observed in different values. According to the results, it can be stated that applied static magnetic field could be considered a potential stressor influencing the fitness components and antioxidant defense in Drosophila flies.
Show more [+] Less [-]Heavy metal accumulation and source analysis in greenhouse soils of Wuwei District, Gansu Province, China
2015
Bai, L. Y. | Zeng, X. B. | Su, S. M. | Duan, R. | Wang, Y. N. | Gao, X.
Greenhouse soils and arable (wheat field) soil samples were collected to identify the effects of greenhouse cultivation on the accumulation of six heavy metals (Cd, Cu, Zn, Pb, Cr, and Ni) and to evaluate the likely sources responsible for heavy metal accumulation in the irrigated desert soils of Wuwei District, China. The results indicated that the mean concentrations of Cd, Cu, Zn, Pb, Cr, and Ni were 0.421, 33.85, 85.31, 20.76, 53.12, and 28.59 mg kg⁻¹, respectively. The concentrations of Cd, Cu, and Zn in greenhouse soils were 60, 23, and 14 % higher than those in arable soils and 263, 40, and 25 % higher than background concentrations of natural soils in the study area, respectively. These results indicated that Cd, Cu, and Zn accumulation occurred in the greenhouse soils, and Cd was the most problematically accumulated heavy metal, followed by Cu and Zn. There was a significant positive correlation between the concentrations of Cd, Cu, and Zn in greenhouse soils and the number of years under cultivation (P < 0.05). Greenhouse cultivation had little impact on the accumulation of Cr, Ni, or Pb. Correlation analysis and principal component analysis suggested that the accumulation of Cd, Cu, and Zn in greenhouse soils resulted mainly from fertilizer applications. Our results indicated that the excessive and long-term use of fertilizers and livestock manures with high heavy metal levels leads to the accumulation of heavy metals in soils. Therefore, rational fertilization programs and reductions in the concentrations of heavy metals in both fertilizers and manure must be recommended to maintain a safe concentration of heavy metals in greenhouse soils.
Show more [+] Less [-]Prediction of water quality index in constructed wetlands using support vector machine
2015
Mohammadpour, Reza | Shaharuddin, Syafiq | Chang, Chun Kiat | Zakaria, Nor Azazi | Ghani, Aminuddin Ab | Chan, Ngai Weng
Poor water quality is a serious problem in the world which threatens human health, ecosystems, and plant/animal life. Prediction of surface water quality is a main concern in water resource and environmental systems. In this research, the support vector machine and two methods of artificial neural networks (ANNs), namely feed forward back propagation (FFBP) and radial basis function (RBF), were used to predict the water quality index (WQI) in a free constructed wetland. Seventeen points of the wetland were monitored twice a month over a period of 14 months, and an extensive dataset was collected for 11 water quality variables. A detailed comparison of the overall performance showed that prediction of the support vector machine (SVM) model with coefficient of correlation (R²) = 0.9984 and mean absolute error (MAE) = 0.0052 was either better or comparable with neural networks. This research highlights that the SVM and FFBP can be successfully employed for the prediction of water quality in a free surface constructed wetland environment. These methods simplify the calculation of the WQI and reduce substantial efforts and time by optimizing the computations.
Show more [+] Less [-]Mining in New Caledonia: environmental stakes and restoration opportunities
2015
Losfeld, Guillaume | L’Huillier, Laurent | Fogliani, Bruno | Jaffré, Tanguy | Grison, Claude
New Caledonia is a widely recognised marine and terrestrial biodiversity hot spot. However, this unique environment is under increasing anthropogenic pressure. Major threats are related to land cover change and include fire, urban sprawling and mining. Resulting habitat loss and fragmentation end up in serious erosion of the local biodiversity. Mining is of particular concern due to its economic significance for the island. Open cast mines were exploited there since 1873, and scraping out soil to access ores wipes out flora. Resulting perturbations on water flows and dramatic soil erosion lead to metal-rich sediment transport downstream into rivers and the lagoon. Conflicting environmental and economic aspects of mining are discussed in this paper. However, mining practices are also improving, and where impacts are inescapable ecological restoration is now considered. Past and ongoing experiences in the restoration of New Caledonian terrestrial ecosystems are presented and discussed here. Economic use of the local floristic diversity could also promote conservation and restoration, while providing alternative incomes. In this regard, Ecocatalysis, an innovative approach to make use of metal hyperaccumulating plants, is of particular interest.
Show more [+] Less [-]Oxidative stress tolerance in intertidal red seaweed Hypnea musciformis (Wulfen) in relation to environmental components
2015
Maharana, Dusmant | Das, Priya Brata | Verlecar, Xivanand N. | Pise, Navnath M. | Gauns, Manguesh
Oxidative stress parameters in relation to temperature and other factors have been analysed in Hypnea musciformis, the red seaweed from Anjuna beach, Goa, with an aim to understand its susceptibility to the changing seasons. The results indicate that elevated temperature, sunshine and dessication during peak summer in May enhanced the activity of lipid peroxide, hydrogen peroxide and antioxidants such as catalase, glutathione and ascorbic acid. Statistical tests using multivariate analysis of variance and correlation analysis showed that oxidative stress and antioxidants maintain significant relation with temperature, salinity, sunshine and pH at an individual or interactive level. The dissolved nitrates, phosphates and biological oxygen demand in ambient waters and the trace metals in seaweeds maintained sufficiently low values to provide any indication that could exert contaminant oxidative stress responses. The present field studies suggest that elevated antioxidant content in H. musciformis offer sufficient relief to sustain against harsh environmental stresses for its colonization in the rocky intertidal zone.
Show more [+] Less [-]The influence of Ce doping of titania on the photodegradation of phenol
2015
Martin, Marcela V. | Villabrille, Paula I. | Rosso, Janina A.
Pure and cerium-doped [0.05, 0.1, 0.3, 0.5, and 1.0 Ce nominal atomic % (at.%)] TiO₂ was synthesized by the sol–gel method. The obtained catalysts were characterized by X-ray diffraction (XRD), UV–visible diffused reflectance spectroscopy (DRS), Raman, and BET surface area measurement. The photocatalytic activity of synthesized samples for the oxidative degradation of phenol in aqueous suspension was investigated. The content of Ce in the catalysts increases both the transition temperature for anatase to rutile phase transformation and the specific surface area, and decreases the crystallite size of anatase phase, the crystallinity, and the band gap energy value. The material with higher efficiency corresponds to 0.1 Ce nominal at.%. Under irradiation with 350 nm lamps, the degradation of phenol could be described as an exponential trend, with an apparent rate constant of (9.1 ± 0.6) 10⁻³ s⁻¹ (r ² = 0.98). Hydroquinone was identified as the main intermediate.
Show more [+] Less [-]Health risk assessment of metals in food crops and related soils amended with biogas slurry in Taihu Basin: perspective from field experiment
2015
Bian, Bo | suo Wu, Hai | Lv, Lin | Fan, Yamin | Lu, Haiming
A health risk assessment of food crops contaminated with heavy metals (Cu, Zn, Pb, As, Cd, and Cr) through the intake of cereals and vegetables grown from biogas slurry irrigated sites was conducted. In the vegetable soils and cereal soils, the concentrations of Zn, Pb, and Cd were far higher than Chinese agricultural standards. The pollution conditions of the aforementioned heavy metals varied with the seasons. Typically, the pollution was more serious in summer than in autumn. Furthermore, the accumulative properties of the heavy metals were different in the cereals and vegetables. In particular, Cu, Zn, and Pb tended to accumulate in rice with concentrations of 6.70, 36.58, and 4.14 mg kg⁻¹, respectively. Pb and Cd in cereals and vegetables exceeded the maximum permissible concentrations in China. The health risk assessment revealed that the daily intake (DI) and target hazard quotients (THQs) of Pb, As, and Cd in cereals and vegetables also exceeded the FAO/WHO limit. The results indicated that heavy metal contamination posed a severe health risk to local humans.
Show more [+] Less [-]Reducing soil erosion and nutrient loss on sloping land under crop-mulberry management system
2015
Fan, Fangling | Xie, Deti | Wei, Chaofu | Ni, Jiupai | Yang, John | Tang, Zhenya | Zhou, Chuan
Sloping croplands could result in soil erosion, which leads to non-point source pollution of the aquatic system in the Three Gorges Reservoir Region. Mulberry, a commonly grown cash plant in the region, is traditionally planted in contour hedgerows as an effective management practice to control soil erosion and non-point source pollution. In this field study, surface runoff and soil N and P loss on sloping land under crop-mulberry management were investigated. The experiments consisted of six crop-mulberry treatments: Control (no mulberry hedgerow with mustard-corn rotation); T1 (two-row contour mulberry with mustard-corn rotation); T2 (three-row contour mulberry with mustard-corn rotation); T3 (border mulberry and one-row contour mulberry with mustard-corn rotation); T4 (border mulberry with mustard-corn rotation); T5 (two-row longitudinal mulberry with mustard). The results indicated that crop-mulberry systems could effectively reduce surface runoff and soil and nutrient loss from arable slope land. Surface runoff from T1 (342.13 m³ hm⁻²), T2 (260.6 m³ hm⁻²), T3 (113.13 m³ hm⁻²), T4 (114 m³ hm⁻²), and T5 (129 m³ hm⁻²) was reduced by 15.4, 35.6, 72.0, 71.8, and 68.1 %, respectively, while soil loss from T1 (0.21 t hm⁻²), T2 (0.13 t hm⁻²), T3 (0.08 t hm⁻²), T4 (0.11 t hm⁻²), and T5 (0.12 t hm⁻²) was reduced by 52.3, 70.5, 81.8, 75.0, and 72.7 %, respectively, as compared with the control. Crop-mulberry ecosystem would also elevate soil N by 22.3 % and soil P by 57.4 %, and soil nutrient status was contour-line dependent.
Show more [+] Less [-]An environmentally friendly method for the determination of triazine herbicides in estuarine seawater samples by dispersive liquid–liquid microextraction
2015
Rodríguez-González, N. | Beceiro-González, E. | González-Castro, M. J. | Muniategui-Lorenzo, S.
A fast, simple, sensitive and green chemistry method using dispersive liquid–liquid microextraction (DLLME) for the simultaneous determination of seven triazine herbicides (ametryn, atrazine, cyanazine, propazine, simazine, simetryn and terbuthylazine) in estuarine seawater samples has been developed. DLLME was carried out using a small volume of seawater (25 mL) and 300 μL of 1-octanol. Herbicide concentrations were determined by liquid chromatography-diode array detection, and results were confirmed by liquid chromatography-electrospray ionisation tandem spectrometry analysis. The analytical features of the proposed method were satisfactory with repeatability < ±5 % and intermediate precision < ±10 %, and recoveries ranged from 81–102 % for all compounds. All the triazines exhibited linear matrix calibration curves with coefficients of determination >0.999 for all the analytes except for simazine (0.9975). Limits of quantification ranged between 0.19 and 1.12 μg L⁻¹. The method was applied to the analysis of seawater samples from ten points susceptible to contamination by triazines from estuary of A Coruña (Galicia, NW of Spain). The levels of the seven triazines were below the LODs in the analysed samples. Use of proposed method will allow for monitoring of triazines at levels below the regulatory limits set by the European Directive 2008/105/EC of 2 and 4 μg L⁻¹ for atrazine and simazine, respectively.
Show more [+] Less [-]Assessment of cadmium (Cd) concentration in arable soil in China
2015
Zhang, Xiuying | Chen, Dongmei | Zhong, Taiyang | Zhang, Xiaomin | Cheng, Min | Li, Xinhui
Cadmium (Cd) concentration in arable soil has drawn broad public attention due to its direct effect on Cd concentration in food. However, there have been few studies of surveying Cd accumulation on the national scale in China. This paper collected 486 studies of Cd concentrations in Chinese arable soil. The results showed that the average Cd concentration was 0.27 mg/kg, higher than its background value, indicating that Cd had been introduced into arable soil by human activity. The Cd concentrations in areas of mining and smelting, urban areas, and areas irrigated by wastewater were obviously higher than that in remote areas. Spatially, Cd concentrations were lower in the north than those in the south, and many hotspots existed throughout China due to mining and smelting activities. Most Cd in the arable soil were accumulated from external sources in all investigated provinces except Ningxia Hui Autonomous Region.
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