Refinar búsqueda
Resultados 3861-3870 de 8,010
Environmental quality: examining role of financial development, institutional capacity, and corruption Texto completo
2021
Kumar, Ameet | Kalhoro, Muhammad Ramzan | Kumar, Rakesh | Bhutto, Niaz Ahmed | Shaikh, Ruqia
This study aims to investigate the influence of institutional capacity on the relationship between financial development and environmental quality and also examines the moderating role of corruption on the link between institutional quality and environmental quality. By using yearly data from 33 developing countries for 7 years from 2011 to 2017, this paper applies a dynamic technique system GMM. The results suggest that financial development increases environmental degradation due to possible higher energy-intensive investment. However, institutional capacity moderates its impact on environmental quality by channelizing the funds to energy-efficient investment. The findings of this study suggest that financial development improves the environmental quality when institutional capacity is higher than 3.5 on the scale of 0 to 6. Interestingly, institutional capacity is unable to control environmental degradation in the presence of corruption. The results propose that financial development has a positive relation with environmental degradation in the presence of corruption. Nevertheless, relationship between institutional capacity and environmental degradation turns to negative when corruption improves in the economies. Furthermore, the findings show that institutional capacity may only control environmental degradation when corruption improves to 40 or higher on a scale of 0 to 100. The policy implications of this study are useful for policy departments, environmental regulatory bodies, and financial institutions.
Mostrar más [+] Menos [-]Assessment of trace element pollution and ecological risks in a river basin impacted by mining in Colombia Texto completo
2021
Marrugo-Negrete, José | Pinedo-Hernández, José | Marrugo-Madrid, Siday | Díez, Sergi
Trace element pollution in rivers by anthropogenic activities is an increasing problem worldwide. In this study, the contamination and ecological risk by several trace elements were evaluated along a 100-km stretch of the San Jorge River in Colombia, impacted by different mining activities. The increase of average concentration levels and range of trace elements in sediments (in μg/g) was as follows: Cu 6656 (454–69,702) > Cd 1159 (0.061–16,227) > Zn 1064 (102–13,483) > Ni 105 (31–686) > Pb 7.2 (5.1–11.7) > As 1.8 (1.0–3.2) > Hg 0.31 (0.12–1.37). Results showed that surface sediments could be classified as very high ecological risk index (RI > 600), associated with high contamination of Hg, Cd, and Cu, in stations close mining activities. Values for pollution load index indicate an environmental deterioration (PLI > 1), and sediment quality guidelines (SQGs) suggested that Cu, Ni, Zn, and Hg caused adverse biological effects. We further used pollution indices such as contamination factor (CF), enrichment factor (EF), and geoaccumulation index (Igeo) to assess the extent of contamination. According to these indices, discharges of hazardous chemicals over many years have resulted in a high degree of pollution for Cu, Pb, and Cd, with critical values in stations receiving wastes from mining activities. Multivariate statistical analysis suggested that Hg, Cd, Cu, and Zn derived from gold and coal mining, Ni and As were related from the mining of ferronickel and coal, respectively, whereas the high Pb load was attributed to diffuse source of pollution. In sum, our study provided the first detailed database on metal concentration and ecological risks to organisms in sediments of the San Jorge River Basin, and the current results also suggested future research for public health action.
Mostrar más [+] Menos [-]Florfenicol induces renal toxicity in chicks by promoting oxidative stress and apoptosis Texto completo
2021
Wang, Xiao | Han, Chao | Cui, Yuqing | Geng, Yumeng | Wei, Yuanyuan | Shi, Wanyu | Bao, Yongzhan
To explore the mechanism of renal toxicity induced by florfenicol (FFC), 120 chicks were randomly divided into 6 groups, 20 in each group. Except for the control group, different doses of FFC (0.15 g/L, 0.3 g/L, 0.6 g/L, 1.2 g/L, and 1.8 g/L) were added to drinking water in the other 5 groups. Five days later, blood was collected from the vein under the wing, and the complete kidneys were obtained as soon as possible, then tested the experimental indicators. The results showed that compared with control group, all doses of FFC significantly reduced the average weight gain of chicks (P < 0.05 or P < 0.01). Except for the 0.15 g/L FFC group, kidney index of chicks in the other doses of FFC groups were significantly increased (P < 0.05 or P < 0.01). The kidney tissues in all FFC groups showed obvious damage, deformities, cell atrophy, and cell gap enlargement. In addition, all doses of FFC significantly increased the contents of uric acid (UA), blood urea nitrogen (BUN), creatinine (CRE) in serum, and malondialdehyde (MDA) in renal tissue (P < 0.05 or P < 0.01), but significantly reduced the levels of glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in renal tissue (P < 0.05 or P < 0.01). FFC significantly inhibited the mRNA and protein expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase-1 (NQO-1), and increased the mRNA and protein expression levels of p53, Caspase-3, and Caspase-6 (P < 0.05 or P < 0.01). The apoptotic rate of renal cells in all doses of FFC groups increased significantly (P < 0.05 or P < 0.01). It was concluded that FFC had a certain degree of nephrotoxicity, and with the increase of FFC concentration, the kidney injury of chicks became more and more serious. FFC promoted oxidative stress response in kidney of chicks by inhibiting the expression of related factors in Nrf2-ARE pathway. Moreover, the expression of pro-apoptotic factors was upregulated to improve the apoptosis rate of renal cells, which resulted in excessive apoptosis of renal cells and seriously affected the kidney function of chicks.
Mostrar más [+] Menos [-]Antioxidant activity and enzyme inhibitory potential of Euphorbia resinifera and E. officinarum honeys from Morocco and plant aqueous extracts Texto completo
2021
Boutoub, Oumaima | El-Guendouz, Soukaina | Estevinho, Letícia M. | Paula, Vanessa B. | Aazza, Smail | El Ghadraoui, Lahsen | Rodrigues, Brígida | Raposo, Sara | Carlier, Jorge | Costa, Maria C. | Miguel, Maria G.
Antioxidant activity and enzyme inhibitory potential of Euphorbia resinifera and E. officinarum honeys from Morocco and plant aqueous extracts Texto completo
2021
Boutoub, Oumaima | El-Guendouz, Soukaina | Estevinho, Letícia M. | Paula, Vanessa B. | Aazza, Smail | El Ghadraoui, Lahsen | Rodrigues, Brígida | Raposo, Sara | Carlier, Jorge | Costa, Maria C. | Miguel, Maria G.
Natural products may be applied in a wide range of domains, from agriculture to food and pharmaceutical industries. In this study, the antioxidant properties and the capacity to inhibit some enzymatic activities of Euphorbia resinifera and Euphorbia officinarum aqueous extracts and honeys were assessed. The physicochemical characteristics were also evaluated. Higher amounts of iron, copper and aluminium were detected in E. officinarum honey, which may indicate environmental pollution around the beehives or inadequate storage of honey samples. This honey sample showed higher amounts of total phenols and better capacity for scavenging superoxide anion free radicals and DPPH free radicals as compared with E. resinifera honey, but poorer capacity for inhibiting lipoxygenase, acetylcholinesterase, tyrosinase and xanthine oxidase. The ratio plant mass:solvent volume (1:100) and extraction time (1 - 2 h) were associated with higher total phenols and better antioxidant activities and lipoxygenase, acetylcholinesterase and tyrosinase inhibitory activities, regardless of the plant species. The aqueous extracts had systematically higher in vitro activities than the respective honey samples.
Mostrar más [+] Menos [-]Antioxidant activity and enzyme inhibitory potential of Euphorbia resinifera and E. officinarum honeys from Morocco and plant aqueous extracts Texto completo
2021
Boutoub, Oumaima | EL-Geundouz, Soukaina | Estevinho, Leticia M. | Paula, Vanessa B. | Aazza, Smail | El Ghadraoui, Lahsen | Rodrigues, Brígida | Raposo, Sara | Carlier, Jorge | Costa, Maria Clara | Miguel, Maria
Natural products may be applied in a wide range of domains, from agriculture to food and pharmaceutical industries. In this study, the antioxidant properties and the capacity to inhibit some enzymatic activities ofEuphorbia resiniferaandEuphorbia officinarumaqueous extracts and honeys were assessed. The physicochemical characteristics were also evaluated. Higher amounts of iron, copper and aluminium were detected inE. officinarumhoney, which may indicate environmental pollution around the beehives or inadequate storage of honey samples. This honey sample showed higher amounts of total phenols and better capacity for scavenging superoxide anion free radicals and DPPH free radicals as compared withE. resiniferahoney, but poorer capacity for inhibiting lipoxygenase, acetylcholinesterase, tyrosinase and xanthine oxidase. The ratio plant mass:solvent volume (1:100) and extraction time (1 - 2 h) were associated with higher total phenols and better antioxidant activities and lipoxygenase, acetylcholinesterase and tyrosinase inhibitory activities, regardless of the plant species. The aqueous extracts had systematically higher in vitro activities than the respective honey samples. | FCTPortuguese Foundation for Science and TechnologyEuropean Commission [UID/MAR/00350/2020] | info:eu-repo/semantics/publishedVersion
Mostrar más [+] Menos [-]Remediation of Chlorophenolic Compounds from Paper Mill Effluent Using High-Quality Activated Carbon from Mixed Plastic Waste Texto completo
2021
Vipul, Gupta | Kant, Bhardwaj Nishi | Kumar, Rawal Ravindra
The present study investigated the adsorption efficiency of laboratory-produced activated carbon (AC) from pyrolysis of mix waste plastic (MWP) for treating paper mill effluent. In the present work, adsorbent was prepared from MWP and was characterized in comparison to commercial adsorbents. A lab scale adsorption study was performed in 100 mL batch experiments to get the optimized condition of different variables by eliminating the pollutants from EOP wastewater and was found as AC dose 10.0 g/100 mL, temperature 35 °C, agitation rate 150 rpm, contact time 7 h, and pH 9.0. The EOP wastewater was analyzed for different quality parameters after treating with prepared AC (PW-AC) and two commercial ACs (SC-AC and M-AC) at optimized conditions. The efficiency of ACs was found to be in order as M-AC>PW-AC>SC-AC. The optimized conditions were applied for the removal of chlorophenols using different ACs in comparison to control EOP wastewater. The study revealed that elimination of chlorophenolic compounds from EOP wastewater (7824 ng/L) was the highest in M-AC treatment followed by PW-AC and SC-AC, i.e., 1426 ng/L, 1759 ng/L, and 2200 ng/L, respectively. PW-AC had major impacts on reduction of chloroguaiacols (82%) as well as chlorophenols (80.7%) that were present in chief amount in EOP wastewater. PW-AC was found to be a capable adsorbent for the removal of chlorophenolic compounds from the most toxic bleaching effluents of pulp and paper industry.
Mostrar más [+] Menos [-]Comprehensive evaluation of water resources carrying capacity and analysis of obstacle factors in Weifang City based on hierarchical cluster analysis-VIKOR method Texto completo
2021
Yang, Haiyan | Tan, Yinan | Sun, Xiaobo | Cheng, Xiaowen | Liu, Guangqi | Zhou, Guangyu
This study uses hierarchical cluster analysis (HCA) to screen the evaluation indexes and establishes a comprehensive evaluation index system for water resources carrying capacity (WRCC), based on the VIKOR method and the obstacle degree model for the identification of the main factors affecting the WRCC of Weifang City. The results show that the WRCC of Weifang City has steadily increased from 2008 to 2018. The subsystems referred to society and water environment are currently the main obstacles affecting Weifang’s WRCC, but there is still space for improvement in the future. The areas with low WRCC was Kuiwen District in 2018, which was in a seriously overloaded state, mostly affected by the water resources subsystem. The implementation of measures such as efficiently improving the level of water resources management and the development of water conservancy projects is prominent in water resource planning in Kuiwen District. This study analyzes the current situation of water resources management in order to consider it in strategic decision-making in promoting the improvement of WRCC, which in turn may ensure the realization of a green and sustainable development strategy in the future for Weifang City.
Mostrar más [+] Menos [-]High effective removal of diazinon from aqueous solutions using the magnetic tragacanth-montmorillonite nanocomposite: isotherm, kinetic, and mechanism study Texto completo
2021
Nikzad, Sadaf | Amooey, Ali Akbar | Alinejad-Mir, Ali
Health and environmental impact of pesticide contamination of groundwater has been reported repeatedly in many studies. The removal of diazinon from agricultural wastewater is still of great interest due to using widely in many developing countries. In the presented study, the magnetic tragacanth-montmorillonite nanocomposite was utilized as an adsorbent to remove diazinon from an aqueous solution. The adsorbent properties were characterized using FE-SEM, EDX, FTIR, XRD, BET, and VSM techniques. The influence of adsorbent dosage, pH, contact time, and initial concentration of diazinon was studied in a batch system. Different adsorption kinetics and isotherm models were used to describe the kinetic and equilibrium data. The results indicated that the adsorption kinetic was fitted better with a Elovich kinetic model, and the adsorption isotherm was well described by the Langmuir-Freundlich model, and the maximum adsorption capacity was 416 mg g⁻¹. According to Weber and Morris’s model and Boyd plot, the results demonstrated that the adsorption kinetic was controlled simultaneously by film diffusion and intraparticle diffusion. Besides, a thermodynamic study showed that the removal of diazinon is an endothermic process. Considering the results, magnetic tragacanth-montmorillonite nanoadsorbent has a high capability to remove diazinon from aqueous solution.
Mostrar más [+] Menos [-]Microplastic abundance in beach sediments of the Kiel Fjord, Western Baltic Sea Texto completo
2021
Schroder, Kevin | Kossel, Elke | Lenz, Mark
Microplastic abundance in beach sediments of the Kiel Fjord, Western Baltic Sea Texto completo
2021
Schroder, Kevin | Kossel, Elke | Lenz, Mark
We assessed the abundance of microplastics (0.2–5 mm) in drift line sediments from three sites in Kiel Fjord, Western Baltic Sea. The first site is intensively used by beach visitors, the second is in close proximity to a sewage plant and the third is polluted with large-sized plastic litter. Samples were split into three grain size classes (0.2–0.5, 0.5–1, 1–5 mm), washed with calcium chloride solution, and filtered at 0.2 mm. Filters were then visually inspected, and a total of 180 fragments was classified as microplastics, of which 39% were analyzed using Raman spectroscopy. At the site that is close to a sewage plant as well as at the site with intense beach use, 1.8 and 4.5 particles (fibers plus fragments) per kg of dry sediment were found, respectively, while particle abundances reached 30.2 per kg of dry sediment at the site with high litter loads. Our data suggest that the fragmentation of large plastic debris at site seems to be a relevant source for microplastics in Western Baltic Sea beach sediments.
Mostrar más [+] Menos [-]Microplastic abundance in beach sediments of the Kiel Fjord Texto completo
2021
Schröder, Kevin | Kossel, Elke | Lenz, Mark
We assessed the abundance of microplastic (0.2 - 5 mm) in drift line sediments from three sites in Kiel Fjord, Western Baltic. The first site is intensively used by beach visitors, the second is in close proximity to a sewage plant and the third is polluted with large-sized plastic litter. Samples were split into three grain size classes (0.2 – 0.5, 0.5 – 1.0, 1.0 – 5.0 mm), washed with a calciumchloride solution and filtered at 0.2 mm. Filters were then visually inspected and a total of 180 fragments were classified as microplastic, of which 39 % were analysed using Raman spectroscopy. At the site with intense beach use as well as at the site that is close to a sewage plant 1.8 and 4.5 particles (fibers plus fragments) per kg of dry sediment were found, respectively, while particle abundances reached 30.2 per kg of dry sediment at the site with high litter loads. Our data suggest that intensity of human use and proximity to a sewage plant are not necessarily reliable predictors for high loads of microplastics in beach sediments, while the fragmentation of large plastic debris at site seems to be a relevant contamination source.
Mostrar más [+] Menos [-]Short-term effects of real-time individual fine particulate matter exposure on lung function: a panel study in Zhuhai, China Texto completo
2021
Ye, Zi | Wang, Bin | Mu, Ge | Zhou, Yun | Qiu, Weihong | Yang, Shijie | Wang, Xing | Zhang, Zhuang | Chen, Weihong
Fine particulate matter (PM₂.₅) is still the primary air pollutant in most Chinese cities and its adverse effects on lung function have been widely reported. However, short-term effects of individual exposure to PM₂.₅ on pulmonary expiration flow indices remain largely unknown. In this study, we examined the short-term effects of real-time individual exposure to PM₂.₅ on lung function in a panel of 115 healthy adults. We measured individual real-time PM₂.₅ exposure and lung function. Environmental PM₂.₅ concentrations in the same period were collected from the nearest monitoring station. Generalized linear model was used to assess the effects of individual PM₂.₅ exposure on lung function after adjusting for potential confounders. Individual PM₂.₅ exposure ranged from 18.5 to 42.4 μg/m³ with fluctuations over time and ambient PM₂.₅ concentrations presented a moderate trend of fluctuation at the same day. Except forced expiratory volume in 1 s (FEV₁) decline related to 2-h moving average PM₂.₅ exposure, no significant associations between individual PM₂.₅ exposure and other volume indices including forced vital capacity (FVC) and FEV₁/FVC ratio were observed. The adverse effects of individual PM₂.₅ exposure on pulmonary expiration flow indices including peak expiratory flow (PEF), maximal mid-expiratory flow (MMF) and forced expiratory flow at 50%, and 75% of vital capacity (FEF₅₀% and FEF₇₅%) were observed to be strongest at 2 moving average hours and could last for 24 h. Stratified analysis showed greater and longer effects among participants who were aged over 40 years, males, or smokers. These findings suggested that individual PM₂.₅ exposure was significantly associated with altered lung function, especially with pulmonary expiration flow indices decline, which was strongest at 2 moving average hours and could last for 24 h.
Mostrar más [+] Menos [-]Development trajectory for the temporal and spatial evolution of the resilience of regional tourism environmental systems in 14 cities of Gansu Province, China Texto completo
2021
Yang, Xiuping | Zhang, Dacheng | Liu, Lili | Niu, Jing | Zhang, Xiaobo | Wang, Xiaoyun
The rapid development of the urban economy in China and the accompanying income growth experienced by urban residents have increased demand for tourism and leisure, which has brought pressure on the urban tourism environment system (UTES), making the contradiction between tourism economic development and the ecological environment increasingly acute. While seeking to rationalize the economic, social, and ecological benefits of tourism, reducing the fragility of the UTES and improving its anti-interference and recovery capabilities have become attracted significant attention from scholars in China and elsewhere. This paper establishes a definition of resilience for an UTES and constructs an evaluation index system for it in terms of the social, economic, and ecological environments. It also establishes an entropy weight-TOPSIS resilience evaluation model to measure resilience in regional systems, using ArcGIS to analyze the standard deviation ellipse and center of the gravity track of the resilience. System dynamics was used to construct diagrams of causal relationships and stock flow for the constituent elements of UTES to show the mechanisms that promote its resilience. This paper investigates 14 cities of Gansu Province in particular to simulate the resilience model of a regional system.
Mostrar más [+] Menos [-]