خيارات البحث
النتائج 3251 - 3260 من 4,924
Monitoring the release of anti-inflammatory and analgesic pharmaceuticals in the receiving environment
2019
Aydin, Senar | Aydin, Mehmet Emin | Ulvi, Arzu
The occurrence of anti-inflammatory and analgesic pharmaceuticals (AIAPs) in the effluents of 16 hospitals, influent and effluent of wastewater treatment plant (WWTP), the contribution and mass load of each hospital to WWTP influent, and the removal efficiencies in WWTP were investigated. Environmental risk was also evaluated by toxicity tests using organisms from three different trophic levels. Acetaminophen had the highest concentration in summer and winter samples, followed by ketoprofen, ibuprofen, and naproxen. The total daily load of AIAPs detected in influent of WWTP was 1677 mg/day/1000 inhabitants in summer and 5074 mg/day/1000 inhabitants in winter. The contribution of 16 hospitals to the total AIAP load in influent of WWTP was 11.30% in summer and 7.09% in winter. The highest mass loads were calculated as 203 mg/bed.day in general hospital in summer and 300 mg/bed.day in pediatric hospital in winter. The removal efficiencies of AIAPs in WWTP ranged between 13% and 100% in summer and 0.88% and 99% in winter. WWTP is not sufficient to remove all the AIAPs. Diclofenac (in summer), mefenamic acid, indomethacin, and phenylbutazone exhibited poor removal below 50%. The effluents of the WWTP exhibited a low risk for fish and Daphnia magna and an insignificant risk for algae.
اظهر المزيد [+] اقل [-]TiO2 nanoparticles may alleviate cadmium toxicity in co-treatment experiments on the model hydrophyte Azolla filiculoides
2019
Spanò, Carmelina | Bottega, Stefania | Sorce, Carlo | Bartoli, Giacomo | Ruffini Castiglione, Monica
The hydrophyte Azolla filiculoides can be a useful model to assess if TiO₂ NPs may in some way alleviate the Cd injuries and improve the ability of the plant to cope with this metal. With this mechanistic hypothesis, after a pre-treatment with TiO₂ NPs, A. filiculoides plants were transferred to cadmium-contaminated water with or without TiO₂ nanoparticles. After 5 days of treatment, cadmium uptake, morpho-anatomical, and physiological aspects were studied in plants. The continuous presence of TiO₂ nanoparticles, though not increasing the uptake of cadmium in comparison with a priming treatment, induced a higher translocation of this heavy metal to the aerial portion. Despite the translocation factor was always well below 1, cadmium contents in the fronds, generally greater than 100 ppm, ranked A. filiculoides as a good cadmium accumulator. Higher cadmium contents in leaves did not induce damages to the photosynthetic machinery, probably thanks to a compartmentalization strategy aimed at confining most of this pollutant to less metabolically active peripheral cells. The permanence of NPs in growth medium ensured a better efficiency of the antioxidant apparatus (proline and glutathione peroxidase and catalase activities) and induced a decrease in H₂O₂ content, but did not suppress TBARS level.
اظهر المزيد [+] اقل [-]Cavitation treatment as a means of modifying the antibacterial activity of various feed additives
2019
Bykov, Artyem | Kvan, Olga | Gavrish, Irina | Bykova, Lyudmila | Mezhuyeva, Larisa | Sizentsov, Alexey | Rusyaeva, Margarita | Korol’kova, Daria
The quality of feed, including its microbiological characteristics, is important for the organization of full-value feeding of animals in agriculture. So, the means of non-reagent processing of feeds, including cavitation treatment, are becoming more widespread. In our study, it was shown that the amount of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM) decreases after a 5-min treatment of the test samples (chalk, fuz, bran, and zeolite) (1.1–35 times) compared to untreated samples, while an increase in the duration of exposure is proportional to the expression of the bactericidal effect. A study of the bioluminescent response of the test strain Escherichia coli K12 TG1 under the influence of the test samples showed inhibition of bioluminescence under the action of chalk and an increase in luminescence during incubation with fusa and bran. When examining the growth rates of strains E. Coli 675 and Bifidobacterium longum B379M, it was found that water and zeolite treated with cavitation suppressed the growth of E. coli 675, while the growth of Bifidobacterium longum B379M was higher than the control values at the end of the experiment. So, cavitation processing can cause the death of microflora of feed additives, at the same time, as a result of the dissociation of a complex of organic polymers, contributing to the positive response of probiotic strains. These studies can be used in agriculture in the preparation of feed additives from waste from the processing industry.
اظهر المزيد [+] اقل [-]Centripetal filtration of groundwater to improve the lifetime of an MgO recycled refractory filter: observations and technical challenges
2019
In the context of improving permeable reactive barrier (PRB) filters, axial and a centripetal column tests were performed to compare their evolution in terms of chemical and hydraulic performances. For both tests, the MgO reactive media, made of crushed (< 10 mm) spent MgO–C refractory bricks was used to treat water contaminated with Co and Ni by raising the pH and promoting hydroxide precipitation. As opposed to the traditional cylindrical axial configuration, the centripetal column consists of an annulus of reactive media through which the water flows from the outer radius towards the inner radius. Under similar conditions (total reactive mass, porosity), the centripetal column is expected to delay the breakthrough of contaminants because of its higher cross-section and lower flow speeds at the entrance of the media. However, as we found in this study, the design of a granular radial filter poses several technical problems. Indeed, a breakthrough of the contaminants, accompanied by a decline in pH, was observed much sooner in the centripetal (100 pv) than in the axial (375 pv) filter. This lower performance was deemed to be due to a hydraulic shortcut and was supported by the results of a tracer test (average renewal volume much lower (199 ml) than the theoretical one (7530 ml)) as well as the observation of preferential clogging upon dismounting the radial filter. While the design of a filter that induces a purely radial flow still poses a technical challenge, this study contributes to advance the knowledge for centripetal radial filtration of groundwater in PRBs.
اظهر المزيد [+] اقل [-]Effect of sheep manure-derived biochar on colloidal phosphorus release in soils from various land uses
2019
Hosseini, Seyed Hamid | Liang, Xinqiang | Niyungeko, Christophe | Miaomiao, He | Li, Fayong | Khan, Sangar | Eltohamy, Kamel Mohamed
Colloidal phosphorus (CP) as an additional route of P mobilization in soil solution has gained much attention. A batch experiment was conducted to investigate the effect of sheep manure-derived biochar (SMB) on CP release from various land uses (paddy, vegetable, tea, and citrus) at a rate of 0% as a control treatment (CK), 1% as a low (L) level, 2% as a middle (M) level, and 4% as a high (H) level of SMB application. The CP and MRPcₒₗₗ in the solution increased from 30.58 to 88.97% and from 2.45 to 55.54% of total P (TP), respectively. The SMB enhanced CP release in all the soils and all the treatments (except CK and L levels in tea soil; CK, L, and M levels in vegetable soil; and L and M levels in citrus soil). Multiple linear regression revealed a significant correlation between CP and MRPcₒₗₗ and between colloidal iron, aluminum, calcium, and total organic carbon (Fecₒₗₗ, Alcₒₗₗ, Cacₒₗₗ, and TOCcₒₗₗ) and pH, which may play an important role as CP carriers that could depend on the pH. This study suggests that the application of SMB in the soil at an appropriate rate of 1 and 2% for tea and vegetable soils, respectively, could be beneficial to avoid the risk of CP release in water bodies.
اظهر المزيد [+] اقل [-]Spent pot liner from aluminum industry: genotoxic and mutagenic action on human leukocytes
2019
Andrade-Vieira, Larissa Fonseca | Trento, Marcus Vinícius Cardoso | César, Pedro Henrique Souza | Marcussi, Silvana
Spent pot liner (SPL) is a toxic solid waste generated in the aluminum mining and processing industry. SPL is considered as an environmental pollution agent when is dumped on environment. Thus, it is important to access its toxicological risk for the exposed organisms. The comet assay and micronucleus test are efficient tests to detect genotoxic/mutagenic compounds by DNA damage observation. Therefore, in the present study, the genotoxic potential of SPL was evaluated through the micronucleus and comet assay on human leukocytes. After ethics committee approval (COEP—UFLA n°. CAAE 11355312.8.0000.5060), blood aliquots collected from healthy volunteers were exposed to increasing concentrations of SPL (from 0.1 to 80 g L⁻¹). All SPL treatments, including the lowest concentration applied (0.1 g L⁻¹), significantly increased the micronucleus frequency. The frequency of DNA damage was determined by visual scores (from 0 to 4) and the results were expressed on percentage of damage and arbitrary units (AU). CaCl₂ (0.01 M) was applied as negative control (NC) and doxorubicin (10 μg mL⁻¹) as positive control (PC). It was observed a dose-dependency between SPL treatments: as SPL concentration for cell incubation increases, the frequency of damage on DNA also increases. Cells incubated on the NC presented nucleoids class 0 to 2, while those exposed to SPL presents nucleoids class 0 to 4. SPL-incubated cells increasing significantly the frequency of nucleoids class 4. For the PC, the UA of damage was 267.74, which is lower than the one observed for the treatments with high doses of SPL (40–287.40 g L⁻¹ and 80–315.30 g L⁻¹). Thus, it was demonstrated that the SPL is a genotoxic agent that induces DNA damage on exposed organisms.
اظهر المزيد [+] اقل [-]Response of dust particle pollution and construction of a leaf dust deposition prediction model based on leaf reflection spectrum characteristics
2019
Zhu, Jiyou | Yu, Qiang | Zhu, Hua | He, Weijun | Xu, Chengyang | Liao, Juyang | Zhu, Qiuyu | Su, Kai
Urban plants can improve several environmental pollution problems in cities, especially dust prevention, noise reduction, purification of the atmosphere, etc. To explore the influence of dust deposition on the spectral characteristics of the leaf, a foliar dust deposition prediction model based on high-spectrum data was established. Taking Euonymus japonicus L., the common greening tree species in Beijing, as the research object, high (T1), medium (T2), and low (T3) dust pollution gradients were set and hyperspectral data were collected. Results showed that: (1) in the dust-contaminated environment with different concentrations, the trend of the reflectance curve of the leaves of Euonymus japonicus L. was generally consistent. The spectral reflectance of the leaf surface was positively correlated with the amount of leaf dust. (2) There were five obvious reflection peaks and five main absorption valleys with the same positions and ranges in the 350–2500 nm range. (3) The spectral reflectance of leaf flour dust particles of Euonymus japonicus L. was significantly different before and after dusting, and its size was generally clean leaves > dust-depositing leaves. The sensitive range of its spectral response was 695–1400 nm. (4) The overall trend of the first derivative spectrum was basically the same. The red edge slope and the blue edge slope appeared as T3 > T2 > T1, the red edge position and the blue edge position appeared as T1 < T2 < T3. The red edge position of the leaf surface after dust deposition had an obvious "blueshift", and the moving distance increases with the increase of dust retention on leaf surface. (5) The leaf water index (y = − 1.18x² + 0.5424x + 0.9917, R² = 0.8030, RMSE = 0.187) had the highest accuracy in the regression model of leaf surface dust deposition using spectral parameters. The test showed that the R² reached 0.9019, which indicated that the model has a good fitting effect. This prediction model can effectively estimate the dust deposition of the leaf surface of Euonymus japonicus L.
اظهر المزيد [+] اقل [-]Addition of zeolite and superphosphate to windrow composting of chicken manure improves fertilizer efficiency and reduces greenhouse gas emission
2019
Peng, Shuang | Li, Huijie | Xu, Qianqian | Lin, Xiangui | Wang, Yiming
This study investigated the impact of adding zeolite (F), superphosphate (G), and ferrous sulfate (L) in various combinations on reducing greenhouse gas (GHG) emission and improving nitrogen conservation during factory-scale chicken manure composting, aimed to identify the combination that optimizes the performance of the process. Chicken manure was mixed with F, G, FL, or FGL and subjected to windrow composting for 46 days. Results showed that global warming potential (GWP) was reduced by 21.9% (F), 22.8% (FL), 36.1% (G), and 39.3% (FGL). Further, the nitrogen content in the final composting product increased by 27.25%, 9.45%, and 21.86% in G, FL, and FGL amendments, respectively. The fertilizer efficiency of the compost product was assessed by measuring the biomass of plants grown in it, and it was consistent with the nitrogen content. N₂O emission was negligible during composting, and 98% of the released GHGs comprised CO₂ and CH₄. Reduction in GHG emission was mainly achieved by reducing CH₄ emission. The addition of FL, G, and FGL caused a clear shift in the abundance of dominant methanogens; particularly, the abundance of Methanobrevibacter decreased and that of Methanobacterium and Methanocella increased, which was correlated with CH₄ emissions. Meanwhile, the changes in moisture content, NH₄⁺-N content, and pH level also played an important role in the reduction of GHG emission. Based on the effects of nitrogen conservation, fertilizer efficiency improvement, and GHG emission reduction, we conclude that G and FGL are more beneficial than F or FL and suggest these additives for efficient chicken manure composting.
اظهر المزيد [+] اقل [-]Impact of calcium peroxide dosage on the control of nutrients release from sediment in the anoxic landscape water
2019
Wang, Yi | Wang, Wen-Huai | Lu, Xin-Xin | Feng, Lin-Lin | Xue, Fu-Rong | Sun, Lu-Qin
The anoxic and reductive aquatic environment is formed easily in summer due to the global warming, which may accelerate endogenous release. In this experiment, four different dosages of calcium peroxide (CaO₂) were adopted to study the control effects of nutrients release from the sediments in the simulated landscape waters. The results demonstrated that CaO₂ addition could effectively improve the physicochemical properties and microbial composition in sediments, and an obvious improvement was achieved with a larger dosage. It was observed that the surface sediments of experiment groups were oxidized to form a capping barrier between the sediment and overlying water, which might cut off the pollutant diffusion in sediment. Meanwhile, CaO₂ could decrease the nutrients concentration in water obviously, and the reduced effect was positively correlated with the CaO₂ dosage. Compared with the nutrients release fluxes in CK (105.89 mg-TN m⁻² day⁻¹, 106.48 mg-NH₄⁺-N m⁻² day⁻¹, 4.14 mg-TP m⁻² day⁻¹, and 4.30 mg-SRP m⁻² day⁻¹), the CaO₂ dosages of 0.12 and 0.18 kg m⁻² could entirely inhibit the nutrients release from sediment, and partially reduce the original pollutants in the overlying water. However, 0.18 kg m⁻² CaO₂ would cause a higher increase of pH value and NO₂⁻-N concentration, and bring potential risk to the aquatic ecosystem. Therefore, 0.12 kg-CaO₂ m⁻²-sediment was selected as the optimal dosage by considering the control effect, economic cost, and potential risk comprehensively. In general, this study provided a quantitative usage method of CaO₂, which is convenient and effective to prevent or control the nutrients release from sediment caused by anoxic and reductive condition in summer.
اظهر المزيد [+] اقل [-]Potential of agro-waste sugarcane bagasse ash for the removal of ammoniacal nitrogen from landfill leachate
2019
Mor, Suman | Negi, Pooja | Ravindra, Khaiwal
Ammoniacal nitrogen is considered as one of the major pollutants of the leachate generated from the landfill site and has the potential to deteriorate the environment as well as health. Considering this, locally available agricultural waste, i.e., sugarcane bagasse ash, was employed as an adsorbent for the removal of ammoniacal nitrogen from landfill leachate. Batch-mode experiments were conducted to see the effect of dose (2–60 g L⁻¹), pH (2–12), and temperature (20–60 °C) on ammoniacal nitrogen adsorption. Application of sugarcane bagasse ash showed 60% removal of ammoniacal nitrogen (50 mg L⁻¹ strength) at an optimum dose of 20 g L⁻¹ and 180 min of contact time with an adsorption capacity of 0.31 mg g⁻¹. The Langmuir adsorption model was found to be best fit at 40 °C with R² = 0.944, depicting a monolayer coverage of ammoniacal nitrogen onto sugarcane bagasse ash. According to the result, solute uptake rate could be well described by the pseudo-second-order model (R² = 0.928), whereas the intraparticle diffusion model and Boyd plot indicated that the overall adsorption rate is governed by the external mass transfer. Thermodynamic studies revealed that adsorption is feasible, spontaneous, and endothermic in nature. Hence, the study shows that sugarcane bagasse ash could turn out to be a cost-effective adsorbent for the removal of ammoniacal nitrogen from leachate
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