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Fate of parasites and pathogenic bacteria in an anaerobic hybrid reactor followed by downflow hanging sponge system treating domestic wastewater Texto completo
2015
Tawfik, A. | El-Zamel, T. | Herrawy, A. | El-Taweel, G.
Treatment of domestic wastewater in a pilot-scale upflow anaerobic hybrid (AH) reactor (0.9 m³) in combination with downflow hanging sponge (DHS) system (1.3 m³) was investigated. The combined system was operated at a hydraulic retention time (HRT) of 6.0 h for AH and 3.2 h for DHS system. The total process achieved a substantial reduction of CODₜₒₜₐₗ resulting in an average effluent concentration of only 39 ± 12 mg/l. Moreover, 90 ± 7 % of ammonia was eliminated in the DHS system. Nitrate and nitrite data revealed that 49 ± 3.2 % of the ammonia removal occurred through nitrification process. The removal efficiency of total coliform (TC), fecal coliform (FC), and fecal streptococci (FS) was relatively low in the AH reactor. The major portion of TC, FC, and FS was removed in the DHS system resulting to an average count of 1.7 × 10⁵ ± 1.1 × 10²/100 ml for TC, 7.1 × 10⁴ ± 1.2 × 10²/100 ml for FC, and 7.5 × 10⁴ ± 1.3 × 10²/100 ml for FS in the final effluent. Likely, the combined system was very efficient for the removal of protozoological species such as sarcodins (Entamoeba cysts), flagellates (Giardia cysts), and ciliates (Balantidium cysts). This was not the case for coccidia (Cryptosporidium oocysts), where 36.4 and 27.3 % were detected in the effluent of AH and DHS system, respectively. Only 10 % of intestinal nematode and cestode ova were recorded in the effluent of AH reactor and were completely removed in the DHS system.
Mostrar más [+] Menos [-]PAHs in leachates from thermal power plant wastes and ash-based construction materials Texto completo
2015
Irha, Natalya | Reinik, Janek | Jefimova, Jekaterina | Koroljova, Arina | Raado, Lembi-Merike | Hain, Tiina | Uibu, Mai | Kuusik, Rein
The focus of the current study is to characterise the leaching behaviour of polycyclic aromatic hydrocarbons (PAHs) from oil shale ashes (OSAs) of pulverised firing (PF) and circulating fluidised-bed (CFB) boilers from Estonian Thermal Power Plant (Estonia) as well as from mortars and concrete based on OSAs. The target substances were 16 PAHs from the EPA priority pollutant list. OSA samples and OSA-based mortars were tested for leaching, according to European standard EN 12457-2 (2002). European standard CEN/TC 15862(2012) for monolithic matter was used for OSA-based concrete. Water extracts were analysed by GC–MS for the concentration of PAHs. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene were detected. Still, the release of PAHs was below the threshold limit value for inert waste. The amount of the finest fraction (particle size <0.045 mm), the content of the Al–Si glass phase and the surface characteristics were the main factors, which could affect the accessibility of PAHs for leaching. The mobility of PAHs from OSA of CFB and PF boilers was 20.2 and 9.9 %, respectively. Hardening of OSA-based materials did not lead to the immobilisation of soluble PAHs. Release of PAHs from the monolith samples did not exceed 0.5 μg/m². In terms of leaching of PAHs, OSA is safe to be used for construction purposes.
Mostrar más [+] Menos [-]Dissipation kinetics and degradation mechanism of amicarbazone in soil revealed by a reliable LC-MS/MS method Texto completo
2015
Dong, Maofeng | Han, Wei | Ediage, Emmanuel Njumbe | Fan, Liangxiu | Tang, Hongxia | Wang, Weimin | Han, Lijun | Zhao, Zhihui | Song, Weiguo | Han, Zheng
A sensitive and reliable analytical method was developed for simultaneous determination of amicarbazone (AMZ) and its two major metabolites including desamino amicarbazone (DA) and isopropyl-2-hydroxy-DA-amicarbazone (Ipr-2-OH-DA-AMZ) in soil for the first time. Targeted analytes were extracted and purified using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure, and then analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a total run time of 9 min. The established approach was extensively validated by determining the linearity (R ² ≥ 0.99), recovery (84–96), sensitivity (limits of quantification at 5–10 μg kg⁻¹), and precision (RSDs ≤12 %). Based on the methodological advances, the subsequent dissipation kinetics and degradation mechanism of amicarbazone in soil were thoroughly investigated in an illumination incubator. As revealed, AMZ was easily degraded with the half-lives of 13.9–19.7 days in soil. Field trial results of AMZ (40 g a.i. ha⁻¹) in Shanghai showed that the residues of AMZ and its metabolite Ipr-2-OH-DA-AMZ decreased from 0.505 mg kg⁻¹ (day 50) to 0.038 mg kg⁻¹ (day 365) and from 0.099 mg kg⁻¹ (day 50) to 0.028 mg kg⁻¹ (day 365), respectively, while the content of DA increased from 0.097 mg kg⁻¹ (day 50) to 0.245 mg kg⁻¹ (day 365). This study provided valuable data to understand the toxicity of AMZ and substantially promote its safe application to protect environment and human health.
Mostrar más [+] Menos [-]Using robust Bayesian network to estimate the residuals of fluoroquinolone antibiotic in soil Texto completo
2015
Li, Xuewen | Xie, Yunfeng | Li, Lianfa | Yang, Xunfeng | Wang, Ning | Wang, Jinfeng
Prediction of antibiotic pollution and its consequences is difficult, due to the uncertainties and complexities associated with multiple related factors. This article employed domain knowledge and spatial data to construct a Bayesian network (BN) model to assess fluoroquinolone antibiotic (FQs) pollution in the soil of an intensive vegetable cultivation area. The results show: (1) The relationships between FQs pollution and contributory factors: Three factors (cultivation methods, crop rotations, and chicken manure types) were consistently identified as predictors in the topological structures of three FQs, indicating their importance in FQs pollution; deduced with domain knowledge, the cultivation methods are determined by the crop rotations, which require different nutrients (derived from the manure) according to different plant biomass. (2) The performance of BN model: The integrative robust Bayesian network model achieved the highest detection probability (pd) of high-risk and receiver operating characteristic (ROC) area, since it incorporates domain knowledge and model uncertainty. Our encouraging findings have implications for the use of BN as a robust approach to assessment of FQs pollution and for informing decisions on appropriate remedial measures.
Mostrar más [+] Menos [-]Response of plasma membrane H+-ATPase in rice (Oryza sativa) seedlings to simulated acid rain Texto completo
2015
Liang, Chanjuan | Ge, Yuqing | Su, Lei | Bu, Jinjin
Understanding the adaptation of plants to acid rain is important to find feasible approaches to alleviate such damage to plants. We studied effects of acid rain on plasma membrane H⁺-ATPase activity and transcription, intracellular H⁺, membrane permeability, photosynthetic efficiency, and relative growth rate during stress and recovery periods. Simulated acid rain at pH 5.5 did not affect plasma membrane H⁺-ATPase activity, intracellular H⁺, membrane permeability, photosynthetic efficiency, and relative growth rate. Plasma membrane H⁺-ATPase activity and transcription in leaves treated with acid rain at pH 3.5 was increased to maintain ion homeostasis by transporting excessive H⁺ out of cells. Then intracellular H⁺ was close to the control after a 5-day recovery, alleviating damage on membrane and sustaining photosynthetic efficiency and growth. Simulated acid rain at pH 2.5 inhibited plasma membrane H⁺-ATPase activity by decreasing the expression of H⁺-ATPase at transcription level, resulting in membrane damage and abnormal intracellular H⁺, and reduction in photosynthetic efficiency and relative growth rate. After a 5-day recovery, all parameters in leaves treated with pH 2.5 acid rain show alleviated damage, implying that the increased plasma membrane H⁺-ATPase activity and its high expression were involved in repairing process in acid rain-stressed plants. Our study suggests that plasma membrane H⁺-ATPase can play a role in adaptation to acid rain for rice seedlings.
Mostrar más [+] Menos [-]Pollutant toxicity and detoxification by humic substances: mechanisms and quantitative assessment via luminescent biomonitoring Texto completo
2015
Kudryasheva, N. S. | Tarasova, A. S.
The paper considers mechanisms of detoxification of pollutant solutions by water-soluble humic substances (HSs), natural detoxifying agents. The problems and perspectives of bioassay application for toxicity monitoring of complex solutions are discussed from ecological point of view. Bioluminescence assays based on marine bacteria and their enzymes are of special attention here; they were shown to be convenient tools to study the detoxifying effects on cellular and biochemical levels. The advantages of bioluminescent enzymatic assay for monitoring both integral and oxidative toxicities in complex solutions of model pollutants and HS were demonstrated. The efficiencies of detoxification of the solutions of organic oxidizers and salts of metals (including radioactive ones) by HS were analyzed. The dependencies of detoxification efficiency on time of exposure to HS and HS concentrations were demonstrated. Antioxidant properties of HS were considered in detail. The detoxifying effects of HS were shown to be complex and regarded as ‘external’ (binding and redox processes in solutions outside the organisms) and/or ‘internal’ organismal processes. The paper demonstrates that the HS can stimulate a protective response of bacterial cells as a result of (1) changes of rates of biochemical reactions and (2) stabilization of mucous layers outside the cell walls. Acceleration of auto-oxidation of NADH, endogenous reducer, by HS was suggested as a reason for toxicity increase in the presence of HS due to abatement of reduction ability of intracellular media.
Mostrar más [+] Menos [-]Alternatives to neonicotinoid insecticides for pest control: case studies in agriculture and forestry Texto completo
2015
Furlan, Lorenzo | Kreutzweiser, David
Neonicotinoid insecticides are widely used for control of insect pests around the world and are especially pervasive in agricultural pest management. There is a growing body of evidence indicating that the broad-scale and prophylactic uses of neonicotinoids pose serious risks of harm to beneficial organisms and their ecological function. This provides the impetus for exploring alternatives to neonicotinoid insecticides for controlling insect pests. We draw from examples of alternative pest control options in Italian maize production and Canadian forestry to illustrate the principles of applying alternatives to neonicotinoids under an integrated pest management (IPM) strategy. An IPM approach considers all relevant and available information to make informed management decisions, providing pest control options based on actual need. We explore the benefits and challenges of several options for management of three insect pests in maize crops and an invasive insect pest in forests, including diversifying crop rotations, altering the timing of planting, tillage and irrigation, using less sensitive crops in infested areas, applying biological control agents, and turning to alternative reduced risk insecticides. Continued research into alternatives is warranted, but equally pressing is the need for information transfer and training for farmers and pest managers and the need for policies and regulations to encourage the adoption of IPM strategies and their alternative pest control options.
Mostrar más [+] Menos [-]Solar energy for wastewater treatment: review of international technologies and their applicability in Brazil Texto completo
2015
Marcelino, R. B. P. | Queiroz, M. T. A. | Amorim, C. C. | Leão, M. M. D. | Brites-Nóbrega, F. F.
Several studies have reported the adverse effects of recalcitrant compounds and emerging contaminants present in industrial effluents, which are not degradable by ordinary biological treatment. Many of these compounds are likely to accumulate in living organisms through the lipid layer. At concentrations above the limits of biological tolerance, these compounds can be harmful to the ecosystem and may even reach humans through food chain biomagnification. In this regard, advanced oxidation processes (AOPs) represent an effective alternative for the removal of the pollutants. This study focused on the AOP involving the use of ultraviolet radiation in homogeneous and heterogeneous systems. Based on the literature review, comparisons between natural and artificial light were established, approaching photoreactors constructive and operational characteristics. We concluded that the high availability of solar power in Brazil would make the implementation of the AOP using natural solar radiation for the decontamination of effluents feasible, thereby contributing to clean production and biodiversity conservation. This will serve as an important tool for the enforcement of environmental responsibility among public and private institutions.
Mostrar más [+] Menos [-]A multi-residue method for determination of 70 organic micropollutants in surface waters by solid-phase extraction followed by gas chromatography coupled to tandem mass spectrometry Texto completo
2015
Terzopoulou, Evangelia | Voutsa, Dimitra | Kaklamanos, George
A multi-residue method, based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), has been developed for the determination of 70 organic micropollutants from various chemical classes (organochlorinated, organophosphorous, triazines, carbamate and urea, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pharmaceuticals, phenols, etc.) in surface waters. A single-step SPE extraction using OASIS HLB cartridges was employed for the recovery of target micropollutants. The method has been validated according to monitoring performance criteria of the Water Framework Directive, taking into account the approved guidelines on quality assurance and quality control. The recoveries ranged from 60 to 110 %, the coefficient of variation from 0.84 to 27.4 %, and the uncertainty from 6 to 37 %. The LOD varied from 6.0 to 40 ng/L. The limits of quantification for the priority pollutants anthracene, alachlor, atrazine, benzo(a)pyrene, chlorfenvinphos, diuron, isoproturon, nonylphenol, simazine, and terbutryn fulfill the criterion of <30 % of the relevant environmental standards. The method was employed to investigate the water quality in the basin of a transboundary river, Strymonas, in NE Greece during three sampling campaigns conducted in the year 2013. Thirty-nine compounds were detected in the river water. Metolachlor, diuron, isoproturon, salicylic acid, chlorfenvinphos, 1,2-benzanthracene, pyrene, diflubenzuron, and carbaryl exhibited the highest detection frequencies.
Mostrar más [+] Menos [-]How do two giant panda populations adapt to their habitats in the Qinling and Qionglai Mountains, China Texto completo
2015
Liu, Xuehua | Wang, Tiejun | Wang, Ting | Skidmore, Andrew K. | Songer, Melissa
The spatial separation of the Qinling Mountains from the western mountains has caused morphological and genetic distinctions of giant pandas. Could this separation also cause the pandas’ behavior change? In this research, we focused on the pandas’ movement pattern and selected two wild panda groups in Foping and Wolong Nature Reserves (NR) to represent the populations in the Qinling and Qionglai Mountains, respectively. We hypothesized that the Qinling pandas have developed a different seasonal movement pattern compared with the pandas in the western mountains. We analyzed the radio tracking data from two NRs by using GIS. Our results showed the following significant differences: (1) The Foping pandas live most of the year in the low elevation areas and move higher during June and remain through August while the Wolong pandas live most of the year in the high elevation areas and move lower in April and stay through June; (2) Comparing their low and high elevational areas shows the distinct spatial patterns between reserves, forming two obviously separated clusters in Foping but a single-compact cluster in Wolong; (3) Foping pandas move an average of 425 m ± 147 s.d. daily, while Wolong pandas move an average of 550 m ± 343 s.d. daily; and (4) Three habitat factors (i.e., terrain, temperature, and bamboo nutrient) were taken as the driving forces and analyzed, and they showed a strong support explanation to these different movement behaviors of pandas in two NRs. Our findings have important implications for management, for instance, it needs to be careful considering the behavior difference of the pandas when reintroducing them to the wild.
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