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The key factors and removal mechanisms of sulfadimethoxazole and oxytetracycline by coagulation Полный текст
2020
Zhang, Weichao | Wei, Qunshan | Xiao, Jiuhua | Liu, Yanbiao | Yan, Changzhou | Liu, Jianshe | Sand, Wolfgang | Chow, Christopher W. K.
The effects of coagulant dosage, alkalinity, turbidity, ionic strength, and dissolved organic matter (DOM) on the removal of sulfadimethoxazole (SMZ) and oxytetracycline (OTC) by coagulation were studied and the reaction mechanisms of the coagulation process were revealed in this research. From our results, alkalinity, turbidity, ionic strength, and DOM had different effects on the removal of antibiotics. The SMZ and OTC removals were improved with increase in poly-aluminum chloride (PACl) dosage, whereas the turbidity had less influence on the removal of SMZ and OTC because the adsorption of SMZ and OTC to kaolin was low, confirmed by a control when no PACl added. The hydrolysate of PACl played a more important role than turbidity in SMZ and OTC removals. The SMZ and OTC removals were significantly increased with the increase in alkalinity, which provided a suitable condition in situ for coagulant to form more optimal species of hydrolysate. The ionic strength, which was adjusted by NaNO₃, also had a positive effect on the removal of SMZ but no obvious effect on the OTC removal. Furthermore, DOM had a higher effect on the removal of SMZ than that of OTC. In another word, if a water plant wants to improve the removal of SMZ and OTC by coagulation unit, PACl hydrolysate, alkalinity, and DOM are the three key factors to be considered primarily. Moreover, an experiment for the recovery of antibiotics from the flocs was done and the results showed that OTC and SMZ were removed by different mechanisms. The OTC was removed via complexation formed through the reaction between OTC and coagulant while the SMZ was removed through the pathway of adsorption and inter-particle bridging to the surface of coagulant hydrolysate.
Показать больше [+] Меньше [-]The effects of melatonin on possible damage that will occur on adipocytokines and liver tissue by coadministration of fructose and bisphenol a (BPA) Полный текст
2020
Akçay, Neslihan Coşkun | Ömeroğlu, Suna | Dizakar, Saadet Özen Akarca | Kavutçu, Mustafa | Türkoğlu, İsmail | Eşmekaya, Meriç Arda | Peker, Tuncay Veysel
BPA, one of the environmental endocrine disruptors, and fructose, reason of liver steatosis which is frequently encountered in the daily diet, contribute to the formation of metabolic syndrome (MetS). This study examines the possible effects of concurrent fructose and BPA administration on MetS and determines the effects of melatonin on this process. In the seven identified groups, a total of forty-two adult male Sprague Dawley rats were treated by following fructose, BPA, and melatonin amounts, separately and together: group 1 (control), group 2 (10% aqueous fructose), group 3 (25 mg/kg BPA), group 4 (10% fructose + 25 mg/kg BPA), group 5 (10% fructose + 20 mg/kg melatonin), group 6 (25 mg/kg BPA + 20 mg/kg melatonin), and group 7 (10% fructose + 25 mg/kg BPA + 20 mg/kg melatonin). At the end of 60 days, histochemical, immunohistochemical, and biochemical procedures were performed on liver tissue. As a result, it was seen that BPA and fructose + BPA induced morphological alteration and inflammation and increased intracellular lipid quantity and amount of collagen and reticular fibers. The percentage of apoptotic liver cells stained by annexin V-FITC/PI was lower in group 7 compared to the group 4 (p < 0,001) and also in group 6 compared to the group 3 (p = 0.014). Both BPA and fructose application caused an increase in lipid peroxidation level due to the increase of oxidative stress. Application of melatonin induced antioxidant enzyme activity and reduced lipid peroxidation level. Our results indicate that fructose and BPA administration triggered the formation of MetS, whereas melatonin healed these variations, although not entirely.
Показать больше [+] Меньше [-]Application of chemical and biological tests for estimation of current state of a tailing dump and surrounding soil from the region of Tarniţa, Suceava, Romania Полный текст
2020
Ilieva, Darya M. | Argirova, Maria | Angelova, Lyudmila Y. | Gradinaru, Robert Vasile | Drochioiu, Gabi | Surleva, Andriana R.
This paper presents the results from a study on the current state of tailing dump, surrounding soil and water in the region of Tarniţa-Suceava, Romania. A number of chemical analyses and germination tests were applied in an attempt to estimate the ability of soil to maintain the plants growing, the bioavailability, and heavy metals uptake. Total heavy metals, exchangeable metals, acidity, and carbon and nitrogen content were determined. A modified sequential extraction method was used to determine geochemical phase distribution of heavy metals. The most abundant heavy metals in the studied samples were Cu, Zn, and Pb. Elevated concentrations of As were also found. The results from sequential extraction revealed that up to 51% of copper was retained by amorphous and crystalline iron oxides in soil. Higher content of lead was noticed in amorphous iron oxide fraction. The heavy metal concentration in river water during dry season varied from 0.13 mg/L (Fe) to 4.2 mg/L (Zn) and was below the maximum contamination level for drinking water. The soil toxicity and heavy metal bioavailability of tailing dump material and surrounding soils were studied by germination tests. The germinated plantlets on the studied soils were found to accumulate elevated concentrations of heavy metals thus indicating the bioavailability of soil contaminants. Soil decontamination by distilled water or magnesium nitrate solution was found to be efficient enough to improve the capability of the studied soils to support the germination process.
Показать больше [+] Меньше [-]Effects of soil heavy metal pollution on microbial activities and community diversity in different land use types in mining areas Полный текст
2020
Zhao, Xingqing | Sun, Yu | Huang, Jian | Wang, Hui | Tang, Ding
Microbial activities and community structures play crucial roles in the soil environment and can be served as effective indicators to assess the ecological influence of heavy metal pollution in soil. This article selected soil samples from five land use types (mining area, mineral processing area, heap mining area, tailing area, and vegetable area) in the Shizishan mining area in Tongling, Anhui Province, China. The physicochemical properties, pollution characteristics, enzyme activities (catalase, urease, alkaline phosphatase, neutral phosphatase, cellulase, and sucrase), microbial biomass carbon (MBC), basal respiration (SBR), and metabolic entropy (qCO₂) in soil were determined and compared, and the relationship between environmental factors and the microbial activities and community diversity was analyzed. The results showed that, according to the Nemerow’s Pollution Index (PN), the values were the heap mining area (24.47) > mineral processing area (12.55) > mining area (9.81) > tailings area (6.02) > vegetable area (4.51). With the increase of heavy metal contamination in the sampling area, the six enzyme activities, MBC and SBR decreased, but the qCO₂ increased. Principal coordinate analysis (PCoA) and canonical correlation analysis (CCA) showed that the land use types, soil moisture content (MC), heavy metal content, pH, MBC, SBR, and qCO₂ were significantly affected by the microbial community. The most dominant phyla were Proteobacteria (34.73%), Bacteroidetes (9.25%), Acidobacteria (8.99%), and Chloroflexi (8.68%) at the phylum (0.01) level by a total of 18 phyla. It was also found that Firmicutes and Phormidium were more tolerant to heavy metals. These results contributed to an insight into key environmental variables shaping the microbial activities, community structure, and diversity under various land use types in mining area.
Показать больше [+] Меньше [-]Respiratory health disorders associated with occupational exposure to bioaerosols among workers in poultry breeding farms Полный текст
2020
Younis, Faten | Salem, Eman | Salem, Eman
Working in poultry farms revealed the exposure to chemical and biological emissions (bioaerosols) that might be related to respiratory diseases in the workers and an increased loss in lung function. The current study aimed to determine the respiratory health status among poultry farm workers and to monitor the biological and the environmental conditions at ten poultry farms in Egypt. It reported that the total dust, ammonia (NH₃), and carbon dioxide (CO₂) concentrations in the studied poultry farms did not exceed the permissible exposure limits except farm V where NH₃ was slightly exceeded the recommended levels. 35.7% of the poultry farm workers had positive nose and throat culture (bacterial and fungal). The poultry farm workers had higher prevalence of cough, wheeze, and shortness of breath with lower mean values of spirometric measurements than the controls (P < 0.05). Also, the positive culture poultry farm workers had significantly higher respiratory manifestations and lower spirometry values than negative culture ones (P < 0.05). Therefore, intervention programs for reducing the exposure are amendatory point for the health and safety of poultry farm workers.
Показать больше [+] Меньше [-]China’s CO2 emissions embodied in fixed capital formation and its spatial distribution Полный текст
2020
Gao, Ziyan | Geng, Yong | Wu, Rui | Zhang, Xi | Pan, Hengyu | Jiang, Huijuan
This study aims to measure China’s CO₂ emissions embodied in fixed capital formation (FCF) from 2007 to 2017 by using both a multi-regional input-output (MRIO) model and a single-region input-output model (SRIO). Then decoupling analysis was performed for uncovering the relationship between embodied CO₂ emissions and added values at provincial level. Logarithmic Mean Divisia Index (LMDI) method was further conducted to identify driving factors underlying the growth of embodied CO₂ emissions. Results show that CO₂ emission from FCF doubled from 2436 million tons (Mt) in 2007 to 4820 Mt in 2012, and increased slightly to 5089 Mt in 2017. Electric power, gas, and water production and supply sector (EGW) and manufacturing industry (MFI) sector were two dominant emitters from supply-side perspective, while construction (CON) was the largest demanding sector driving the embodied emissions from upstream sectors. From geographical point of view, northern provinces were the major inter-regional net exporters of embodied CO₂ emissions, while eastern and southern provinces were net importers of embodied CO₂ emissions. Based on such results, policy recommendations are proposed considering the relation between supply and demand sector, inter-provincial CO₂ emission transfer, and local economic development to mitigate CO₂ emissions from China’s FCF.
Показать больше [+] Меньше [-]Gum arabic and collagen hydrolysate extracted from hide fleshing wastes as novel wall materials for microencapsulation of Origanum onites L. essential oil through complex coacervation Полный текст
2020
Ocak, Bugra
Renewable resource–based biodegradable materials attract more attention than petroleum-based biodegradable materials to support the sustainable development of ecology. Obtaining collagen hydrolysate (CH) from hide fleshing wastes of leather industry is an environmentally friendly way to develop multifunctional materials that can contribute to technological advances in different industries. In this study, 2:1, 1:1, and 1 2 ratios of gum arabic (GA) and CH extracted from hide fleshing waste were used as wall materials to encapsulate Origanum onites L. essential oil (OOEO) using the complex coacervation method. The encapsulation yield and efficiency, functional group composition, particle size, morphology, and thermal stability of the obtained OOEO microcapsules were characterized. The results showed that the obtained microcapsules had high encapsulation yield and efficiency, as well as good functional properties such as uniform morphology and low water activity. The best mass ratio for the biopolymers (GA:CH) was 1:1. Scanning electron microscopy analysis showed that OOEO microcapsule samples had a spherical shape. FTIR analysis was performed on obtained microcapsules, confirming the molecular interactions between GA and CH. These findings can be useful in designing an ideal wall material using GA and CH for microencapsulation of essential oils by the complex coacervation method.
Показать больше [+] Меньше [-]Scheelite weathering and tungsten (W) mobility in historical oxidic-sulfidic skarn tailings at Yxsjöberg, Sweden Полный текст
2020
Hällström, Lina P.B. | Alakangas, Lena | Martinsson, Olof
More knowledge of the geochemical behavior of tungsten (W) and associated contamination risks is needed. Therefore, weathering of scheelite (CaWO₄) and secondary sequestration and transport of W to groundwater in historical skarn tailings and surface water downstream of the tailings were studied. The tailings contained 920 mg/kg W, primarily in scheelite. Mineralogical and geochemical analyses were combined to elucidate the geochemical behavior of W in the tailings, and water samples were taken monthly during 2018 to monitor its mobility. In the tailings, a large peak of W was found at 1.5 m depth. There, 30 wt%. of W was present in easily reducible phases, indicating former scheelite weathering. Currently, W is being released from scheelite to water-soluble phases at 2.5 m depth. The release of WO₄²⁻ is hypothetically attributed to anion exchange with CO₃²⁻ released from calcite neutralizing acid produced from pyrrhotite oxidation in the upper tailings and transported downwards to pH conditions > 7. Higher concentrations of dissolved W were found in the groundwater and particulate W in downstream surface water than in reference water, but they were lower than current contamination thresholds. Tungsten showed correlations with hydrous ferric oxides (HFO) in both the tailings and surface water.
Показать больше [+] Меньше [-]Polystyrene seedling trays used as substrate by native plants Полный текст
2020
Battisti, Corrado | Dodaro, Giuseppe | Fanelli, Giuliano
Among polymers, expanded polystyrene (EPS) is increasingly abundant as a form of anthropogenic litter in natural environments, particularly along waterways. Nevertheless, there is still no research focusing on the interaction between this type of litter and biodiversity components. In this note, we reported the first evidence of an interaction between EPS and living native plants along an artificial drainage channel in a land reclaimed area of Tyrrhenian central Italy. We sampled a number of EPS seedling trays, deriving from agricultural activities, obtaining evidence for an interaction between this polymer and plants: on a total of 231 available seedling holes, 16.88% have been occupied from six species (Lycopus europaeus, Poa cfr. trivialis, Stachys palustris, Silene sp., Phragmites australis, Parietariajudaica). The set of species occurring on floating polystyrene trays appears comparable to that occurring on the sides of the land reclaimed channels (locally, L. europaeus and S. palustris are among the most common species of the riverine vegetation). Therefore, it is very probable that floating trays are a random sample of the seed rain of the vegetation of the sides of the channels. However, more research is needed to assess if the plant assemblage growing on EPS is random process or if peculiar substrate exerts some sort of selection on the plant community.
Показать больше [+] Меньше [-]Temporal trend of arsenic in outdoor air PM2.5 in Wuhan, China, in 2015–2017 and the personal inhalation of PM-bound arsenic: implications for human exposure Полный текст
2020
Mao, Xiang | Hu, Xun | Wang, Yao | Xia, Wei | Zhao, Shasha | Wan, Yanjian
Arsenic in fine air particulate matter (PM₂.₅) has been identified as an important factor responsible for the morbidity of lung cancer, which has increased sharply in many regions of China. Some reports in China have shown that arsenic in the air exceeds the ambient air quality standard value, while long-term airborne arsenic concentrations in central China and human exposure via inhalation of PM–bound arsenic (inhalable airborne PM) have not been well characterized. In this study, 579 outdoor air PM₂.₅ samples from Wuhan, a typical city in central China, were collected from 2015 to 2017, and arsenic was measured by inductively coupled plasma-mass spectrometry. Personal exposure to PM-bound arsenic via inhalation and urinary arsenic concentration were also measured. The concentrations of arsenic in PM₂.₅ were in the range of 0.42–61.6 ng/m³ (mean 8.48 ng/m³). The average concentration of arsenic in 2015 (10.7 ng/m³) was higher than that in 2016 (6.81 ng/m³) and 2017 (8.18 ng/m³), exceeded the standard value. The arsenic concentrations in spring and winter were higher than those in summer and autumn. No significant differences (p > 0.05) were found among different sites. The daily intake of arsenic inhalation based on PM₁₀ samples collected by personal samplers (median, 10.8 ng/m³) was estimated. Urban residents inhaled higher levels of PM-bound arsenic than rural residents. Daily intake of arsenic via inhalation accounted for a negligible part (< 1%) of the total daily intake of arsenic (calculated based on excreted urinary arsenic); however, potential associations between the adverse effects (e.g., lung adenocarcinoma) and inhaled PM-bound arsenic require more attention, particularly for those who experience in long-term exposure. This study is the first report of a 3-year temporal trend of airborne PM₂.₅-bound arsenic in central China.
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