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Результаты 1631-1640 из 2,513
Removal and seasonal variability of selected analgesics/anti-inflammatory, anti-hypertensive/cardiovascular pharmaceuticals and UV filters in wastewater treatment plant Полный текст
2014
Golovko, Oksana | Kumar, Vimal | Fedorova, Ganna | Randak, Tomas | Grabic, Roman
Seasonal removal efficiency of 16 pharmaceuticals and personal care products was monitored in a wastewater treatment plant in České Budějovice, Czech Republic, over a period of 1 year (total amount of samples, n = 272). The studied compounds included four UV filters, three analgesics/anti-inflammatory drugs and nine anti-hypertensive/cardiovascular drugs. In most cases, elimination of the substances was incomplete, and overall removal rates varied strongly from −38 to 100 %. Therefore, it was difficult to establish a general trend for each therapeutic group. Based on the removal efficiencies (REs) over the year, three groups of target compounds were observed. A few compounds (benzophenon-1, valsartan, isradipine and furosemide) were not fully removed, but their REs were greater than 50 %. The second group of analytes, consisting of 2-phenylbenzimidazole-5-sulfonic acid, tramadol, sotalol, metoprolol, atenolol and diclofenac, showed a very low RE (lower than 50 %). The third group of compounds showed extremely variable RE (benzophenon-3 and benzophenon-4, codeine, verapamil, diltiazem and bisoprolol). There were significant seasonal trends in the observed REs, with reduced efficiencies in colder months.
Показать больше [+] Меньше [-]Concentration and characterization of airborne particles in Tehran’s subway system Полный текст
2014
Kamani, Hosein | Hoseini, Mohammad | Seyedsalehi, Mahdi | Mahdavi, Yousef | Jaafari, Jalil | Safari, Gholam Hosein
Particulate matter is an important air pollutant, especially in closed environments like underground subway stations. In this study, a total of 13 elements were determined from PM₁₀and PM₂.₅samples collected at two subway stations (Imam Khomeini and Sadeghiye) in Tehran’s subway system. Sampling was conducted in April to August 2011 to measure PM concentrations in platform and adjacent outdoor air of the stations. In the Imam Khomeini station, the average concentrations of PM₁₀and PM₂.₅were 94.4 ± 26.3 and 52.3 ± 16.5 μg m⁻³in the platform and 81.8 ± 22.2 and 35 ± 17.6 μg m⁻³in the outdoor air, respectively. In the Sadeghiye station, mean concentrations of PM₁₀and PM₂.₅were 87.6 ± 23 and 41.3 ± 20.4 μg m⁻³in the platform and 73.9 ± 17.3 and 30 ± 15 μg m⁻³, in the outdoor air, respectively. The relative contribution of elemental components in each particle fraction were accounted for 43 % (PM₁₀) and 47.7 % (PM₂.₅) in platform of Imam Khomeini station and 15.9 % (PM₁₀) and 18.5 % (PM₂.₅) in the outdoor air of this station. Also, at the Sadeghiye station, each fraction accounted for 31.6 % (PM₁₀) and 39.8 % (PM₂.₅) in platform and was 11.7 % (PM₁₀) and 14.3 % (PM₂.₅) in the outdoor. At the Imam Khomeini station, Fe was the predominant element to represent 32.4 and 36 % of the total mass of PM₁₀and PM₂.₅in the platform and 11.5 and 13.3 % in the outdoor, respectively. At the Sadeghiye station, this element represented 22.7 and 29.8 % of total mass of PM₁₀and PM₂.₅in the platform and 8.7 and 10.5 % in the outdoor air, respectively. Other major crustal elements were 5.8 % (PM₁₀) and 5.3 % (PM₂.₅) in the Imam Khomeini station platform and 2.3 and 2.4 % in the outdoor air, respectively. The proportion of other minor elements was significantly lower, actually less than 7 % in total samples, and V was the minor concentration in total mass of PM₁₀and PM₂.₅in both platform stations.
Показать больше [+] Меньше [-]Polycyclic aromatic hydrocarbon contamination in an urban area assessed by Quercus ilex leaves and soil Полный текст
2014
De Nicola, F. | Alfani, A. | Maisto, G.
We investigated the PAH contamination of Naples urban area, densely populated and with high traffic flow, by analyses of environmental matrices: soil and Quercus ilex leaves. Being some PAHs demonstrated to have hazardous effects on human health, the accumulation of carcinogenic and toxic PAHs (expressed as B(a)Peq) was evaluated in the leaves and soil. The main sources of the PAHs were discriminated by the diagnostic ratios in the two matrices. The urban area appeared heavily contaminated by PAHs, showing in soil and leaves total PAH concentrations also fivefold higher than those from the remote area. The soil mainly accumulated heavy PAHs, whereas leaves the lightest ones. Median values of carcinogenic PAH concentrations were higher in soil (440 ng g⁻¹ d.w.) and leaves (340 ng g⁻¹ d.w.) from the urban than the remote area (60 and 70 ng g⁻¹ d.w., respectively, for soil and leaves). Also, median B(a)Peq concentrations were higher both in soil and leaves from the urban (137 and 63 ng g⁻¹ d.w., respectively) than those from the remote area (19 and 49 ng g⁻¹ d.w., respectively). Different from the soils, the diagnostic ratios found for the leaves discerned PAH sources in the remote and urban areas, highlighting a great contribution of vehicular traffic emission as main PAH source in the urban area.
Показать больше [+] Меньше [-]Effect of cadmium on cytogenetic toxicity in hairy roots of Wedelia trilobata L. and their alleviation by exogenous CaCl2 Полный текст
2014
Shi, He Ping | Zhu, Yuan Feng | Wang, Yun Ling | Tsang, Po Keung Eric
Effects of cadmium (Cd) alone and in combination with calcium on mitosis and chromosomal aberration in the hairy root tips of Wedelia trilobata were investigated. The results showed that Cd concentrations below 50 μmol/L had a lesser or even a promoting effect on the mitotic index (MI) and the rate of chromosomal aberration in hairy root tips, while those higher than 100 μmol/L significantly decreased the MI and gradually stimulated the rate of chromosomal aberrations with prolonged time and increasing concentrations of Cd. Concentrations of 50 μmol/L Cd mainly induced C-mitosis, while more than 100 μmol/L Cd mainly caused chromosome breakage and chromosome adhesion in hairy root tip cells. When cultured with 300 μmol/L Cd, micronuclei were only observed in the interphase, middle, and late phase of hairy root tip cells. Compared with untreated controls, exogenous calcium had an alleviating effect on Cd-induced cytotoxicity by effectively enhancing the MI and reducing the rate of chromosomal aberration in root tip cells. The results presented here provide evidence that W. trilobata hairy roots with rapid autonomous growth could be used as a sensitive tool for monitoring and evaluation of Cd pollution in the environment.
Показать больше [+] Меньше [-]The levels of PAHs and aryl hydrocarbon receptor effects in sediments of Taihu Lake, China Полный текст
2014
Lei, Bingli | Kang, Jia | Wang, Xuetong | Yu, Yingxin | Zhang, Xiaolan | Wen, Yu | Wang, Yipei
A total of 16 priority polycyclic aromatic hydrocarbons (PAHs) in sediment samples from Taihu Lake were analyzed by instruments, and sediment extracts were assayed for aryl hydrocarbon receptor (AhR)-mediated ethoxyresorufin-o-deethylase (EROD) induction using a rat hepatoma cell line (H4IIE). The cause–effect relationship between the observed EROD activity and chemical concentrations of PAHs was examined. Our results showed that sediment extracts could induce significant AhR effects, and the bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents of raw extracts (TEQbᵢₒs) ranged from 2.7 to 39.8 pg g⁻¹dw. Chemical analysis showed that 16 PAHs were all detected in all samples, and their total concentrations (Σ₁₆PAHs) ranged from 179.8 to 1,669.4 ng g⁻¹dw. The abundance of sedimentary PAHs in the three regions (Meiliang Bay, Gonghu Bay, and Xukou Bay) showed a decreasing trend from the inflow region to the outflow region. Chemical analysis-derived TEQs (TEQcₐₗs) contributed by PAHs ranged from 1.6 to 20.7 pg g⁻¹dw. The mean contribution rates (CRs) of PAHs to TEQbᵢₒs were 48.9 %. In Meiliang Bay, EROD effects of 60 % samples were caused by PAHs whose CRs were more than 60 %, while in most sampling sites of Gonghu Bay and Xukou Bay, the CRs of PAHs to TEQbᵢₒs were basically below 40 %. In addition, preliminary ecological risk assessment found that PAHs in sediments have very low ecological impact based on the chemical data of PAHs, while the sediments might pose an unacceptable risk to aquatic organisms and their predators based on the data of TEQbᵢₒ. These findings showed that EROD effects of sediment extracts from Taihu Lake were also caused by other compounds, such as dioxins, polychlorinated biphenyls, etc., together.
Показать больше [+] Меньше [-]Reuse of hydroponic waste solution Полный текст
2014
Kumar, Ramasamy Rajesh | Cho, Jae Young
Attaining sustainable agriculture is a key goal in many parts of the world. The increased environmental awareness and the ongoing attempts to execute agricultural practices that are economically feasible and environmentally safe promote the use of hydroponic cultivation. Hydroponics is a technology for growing plants in nutrient solutions with or without the use of artificial medium to provide mechanical support. Major problems for hydroponic cultivation are higher operational cost and the causing of pollution due to discharge of waste nutrient solution. The nutrient effluent released into the environment can have negative impacts on the surrounding ecosystems as well as the potential to contaminate the groundwater utilized by humans for drinking purposes. The reuse of non-recycled, nutrient-rich hydroponic waste solution for growing plants in greenhouses is the possible way to control environmental pollution. Many researchers have successfully grown several plant species in hydroponic waste solution with high yield. Hence, this review addresses the problems associated with the release of hydroponic waste solution into the environment and possible reuse of hydroponic waste solution as an alternative resource for agriculture development and to control environmental pollution.
Показать больше [+] Меньше [-]Degree of phosphorus saturation of an Oxisol amended with biosolids in a long-term field experiment Полный текст
2014
Alleoni, Luís Reynaldo Ferracciú | Fernandes, Antônio Rodrigues | de Campos, Murilo
When applied to agricultural soils, phosphate fertilizers and the mineral or organic compounds present in solid and/or liquid waste may raise phosphorus (P) content and increase soil P saturation. The degree of phosphorus saturation (DPS) is a good indicator of potential P loss from agricultural soils. The purpose of this study was to calculate the DPS of samples from an Oxisol amended for 5 years with biosolids and mineral fertilizer. DPS was calculated based on P, iron, and aluminum extracted by ammonium oxalate and oxalic acid (DPSₒₓ) or by Mehlich-1 solution (DPSM₁). Treatments included NPK mineral fertilization (175 kg ha⁻¹of P), B1 = 19.02 t ha⁻¹of biosolids (350 kg ha⁻¹of P), B2 = 38.17 t ha⁻¹of biosolids (703 kg ha⁻¹of P), B3 = 76.26 t ha–¹of biosolids (1,405 kg ha⁻¹of P), and a control (no P added). Water-extractable P (WEP) was also measured. Critical levels of DPSₒₓand DPSM₁(21 and 24 %, respectively) were only achieved in the topsoil (0–0.1 m) at the highest biosolid dose. Concentration of WEP was positively correlated to DPSₒₓand DPSM₁. The DPSM₁method may be an alternative to DPSₒₓfor assessing the environmental risk of P loss from soil into surface runoff.
Показать больше [+] Меньше [-]Variations in source apportionments of nutrient load among seasons and hydrological years in a semi-arid watershed: GWLF model results Полный текст
2014
Du, Xinzhong | Li, Xuyong | Zhang, Wangshou | Wang, Huiliang
Quantifying source apportionments of nutrient load and their variations among seasons and hydrological years can provide useful information for watershed nutrient load reduction programs. There are large seasonal and inter-annual variations in nutrient loads and their sources in semi-arid watersheds that have a monsoon climate. The Generalized Watershed Loading Function model was used to simulate monthly nutrient loads from 2004 to 2011 in the Liu River watershed, Northern China. Model results were used to investigate nutrient load contributions from different sources, temporal variations of source apportionments and the differences in the behavior of total nitrogen (TN) and total phosphorus (TP). Examination of source apportionments for different seasons showed that point sources were the main source of TN and TP in the non-flood season, whereas contributions from diffuse sources, such as rural runoff, soil erosion, and urban areas, were much higher in the flood season. Furthermore, results for three typical hydrological years showed that the contribution ratios of nutrient loads from point sources increased as streamflow decreased, while contribution ratios from rural runoff and urban area increased as streamflow increased. Further, there were significant differences between TN and TP sources on different time scales. Our findings suggest that priority actions and management measures should be changed for different time periods and hydrological conditions, and that different strategies should be used to reduce loads of nitrogen and phosphorus effectively.
Показать больше [+] Меньше [-]Comparative quantification of oxygen release by wetland plants: electrode technique and oxygen consumption model Полный текст
2014
Wu, Haiming | Liu, Jufeng | Zhang, Jian | Li, Cong | Fan, Jinlin | Xu, Xiaoli
Understanding oxygen release by plants is important to the design of constructed wetlands for wastewater treatment. Lab-scale systems planted with Phragmites australis were studied to evaluate the amount of oxygen release by plants using electrode techniques and oxygen consumption model. Oxygen release rate (0.14 g O₂/m²/day) measured using electrode techniques was much lower than that (3.94–25.20 gO₂/m²/day) calculated using the oxygen consumption model. The results revealed that oxygen release by plants was significantly influenced by the oxygen demand for the degradation of pollutants, and the oxygen release rate increased with the rising of the concentration of degradable materials in the solution. The summary of the methods in qualifying oxygen release by wetland plants demonstrated that variations existed among different measuring methods and even in the same measuring approach. The results would be helpful for understanding the contribution of plants in constructed wetlands toward actual wastewater treatment.
Показать больше [+] Меньше [-]Assessment of competitive ability of two Indian wheat cultivars under ambient O3 at different developmental stages Полный текст
2014
Rai, Richa | Agrawal, Madhoolika
The concentrations of O₃are increasing, which may have potential adverse effects on crop yield. This paper deals with assessing the intraspecific variability of two wheat cultivars (PBW 343 and M 533) at different growth stages using open top chambers. Mean O₃concentrations were 50.2 and 53.2 ppb, and AOT40 values were 9 and 12.1 ppm h, respectively, in 2008–2009 and 2009–2010. Reproductive stage showed higher AOT40 values (6.9 and 9.2 ppm h) compared to vegetative (2.23 and 2.9 ppm h). Critical levels of a 3-month AOT 40 of 3 ppm h led to 6 % yield reduction in two wheat cultivars for two consecutive years. Variations in photosynthesis rate, stomatal conductance (gₛ), Fv/Fm ratio, photosynthetic pigments, primary and secondary metabolites, morphological parameters, and yield attributes were measured at vegetative and reproductive stages. Reductions in number of leaves, leaf area, total biomass, root/shoot ratio, RGR, photosynthetic pigments, protein content, and Fv/Fm ratio in PBW 343 were more than M 533 at reproductive stage. Photosynthetic rate did not vary between the cultivars, but gₛwas higher in PBW 343 compared to M 533 under ambient O₃. Higher total phenolics and peroxidase activity were recorded in M 533 at reproductive stage conferring higher resistance at latter age. Results of O₃resistance showed that M 533 was sensitive compared to PBW 343 during vegetative stage but developed more resistance at reproductive stage. PBW 343 with larger leaf area and high gₛis more sensitive than M 533 with smaller leaf area and low gₛ. The study suggests that the sensitivity varied with plant growth stage, and the plant showing higher sensitivity during vegetative period developed more resistance during reproductive period due to higher defense mechanism. Though the yield reductions were same in both cultivars under ambient O₃, the mechanism of acquiring the resistance is different between the cultivars.
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