خيارات البحث
النتائج 4371 - 4380 من 4,924
Foreign direct investment, environmental regulation, and environmental pollution: an empirical study based on threshold effects for different Chinese regions
2019
Wang, Hui | Liu, Huifang
On the basis of previous studies on the relations among foreign direct investment (FDI), environmental regulation, and environmental pollution, this work uses provincial panel data from 2000 to 2014 to study the effects of FDI and environmental regulation on environmental pollution by applying the panel-corrected standard error (PCSE) method. This paper then utilizes environmental regulation as the threshold variable to estimate the threshold effects of environmental regulation on FDI’s influence on environmental pollution in a threshold regression model for the eastern, central, and western regions of China. The results show that stricter environmental regulation can substantially reduce the pollution in each region. FDI can decrease environmental pollution in the eastern and central regions, but it can increase pollution in the western region. There are double-threshold effects of environmental regulation on the effects of FDI on environmental pollution in each region. When the environmental regulation level is between the first threshold and the second threshold, FDI can decrease environmental pollution much more in the eastern and central regions and increase environmental pollution much less in the western region.
اظهر المزيد [+] اقل [-]Photochemical aging and secondary organic aerosols generated from limonene in an oxidation flow reactor
2019
Sbai, Salah Eddine | Farida, Bentayeb
Oxidation flow reactors (OFRs) are increasingly used to study the formation and evolution of secondary organic aerosols (SOA) in the atmosphere. The OH/HO₂ and OH/O₃ ratios in OFRs are similar to tropospheric ratios. In the present work, we investigated the production of SOA generated by OH oxydation and ozonolysis of limonene in OFR as a function of OH exposure and O₃ exposure. The results are compared with those obtained from the simulation chambers. The precursor gas is exposed to OH concentrations ranging from 2.11 × 10⁸ to 1.91 × 10⁹ molec cm⁻³, with an estimated exposure time in the OFR of 137 s. In the environmental chambers, the precursor was oxidized using OH concentrations between 2.10 × 10⁶ and 2.12 × 10⁷ molec cm⁻³ over exposure times of several hours. In the overlapping OH exposure region, the highest SOA yields are obtained in the OFR, which is explained by the ozonolysis of limonene in the OFR. However, the yields decrease with the increase of OHexp in both systems.
اظهر المزيد [+] اقل [-]Cadmium overload modulates piroxicam-regulated oxidative damage and apoptotic pathways
2019
Abdeen, Ahmed | Abou-Zaid, Omayma A. | Abdel-Maksoud, Hussein A. | Aboubakr, Mohamed | Abdelkader, Afaf | Abdelnaby, Amany | Abo-Ahmed, Ahmed I. | El-Mleeh, Amany | Mostafa, Ola | Abdel-Daim, Mohamed | Aleya, Lotfi
Cadmium (Cd) is a common environmental pollutant that threatens humans’ and animals’ health. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used drugs due to their wide therapeutic action; however, they have significant side effects. Since, under many circumstances, humans and animals may be co-exposed to Cd and NSAIDs, the current investigation was assigned to explore the intertwining relationship between Cd and NSAIDs. Four groups of male Wister rats were used: control group: rats received saline; Cd group: rats received cadmium (Cd, 2 mg/kg) orally; Px group: rats received a NSAID (piroxicam, Px, 7 mg/kg, i.p.); and Cd+Px group: rats received both Cd+Px. All treatments were given once a day for 28 consecutive days. Then, blood samples, stomach, liver, and kidney tissues were collected. The results indicated that Px provoked gastric ulcer indicated by high ulcer index, while Cd had no effect on the gastric mucosa. In addition, treatment with Cd or Px alone significantly induced liver and kidney injuries indicated by serum elevations of AST, ALT, ALP, ALB, total protein, creatinine, and urea along with histopathological alterations. Significant increases in malondialdehyde and reduction in GSH and CAT contents were reported along with up-regulated expression of Bax and Bcl-2 after Cd or Px exposure. However, when Cd and Px were given in a combination, Cd obviously potentiated the Px-inflicted cellular injury and death in the liver and kidney but not in the stomach when compared to their individual exposure. This study concluded that oxidative stress mechanisms were supposed to be the main modulator in promoting Cd and Px toxicities when given in combination.
اظهر المزيد [+] اقل [-]Assessment of elemental composition and properties of copper smelter-affected dust and its nano- and micron size fractions
2019
Ermolin, Mikhail S. | Fedotov, Petr S. | Ivaneev, Alexandr I. | Karandashev, Vasily K. | Burmistrov, Andrey A. | Tatsy, Yury G.
A comprehensive approach has been developed to the assessment of composition and properties of atmospherically deposited dust in the area affected by a copper smelter. The approach is based on the analysis of initial dust samples, dynamic leaching of water soluble fractions in a rotating coiled column (RCC) followed by the determination of recovered elements and characterization of size, morphology and elemental composition of nano-, submicron, and micron par ticles of dust separated using field-flow fractionation in a RCC. Three separated size fractions of dust (<0.2, 0.2–2, and >2 μm) were characterized by static light scattering and scanning electron microscopy, whereupon the fractions were analyzed by ICP-AES and ICP-MS (after digestion). It has been evaluated that toxic elements, which are characteristics for copper smelter emissions (As, Cu, Zn), are accumulated in fraction >2 μm. At the same time, up to 2.4, 3.1, 8.2, 6.7 g/kg of As, Cu, Zn, Pb, correspondently, were found in nanoparticles (<0.2 μm). It has been also shown that some trace elements (Sn, Sb, Ag, Bi, and Tl) are accumulated in fraction <0.2, and their content in this fraction may be one order of magnitude higher than that in the fraction >2 μm, or the bulk sample. It may be assumed that Sn, Sb, Ag, Bi, Tl compounds are adsorbed onto the finest dust particles as compared to As, Cu, Zn compounds, which are directly emitted from the copper smelter as microparticles.
اظهر المزيد [+] اقل [-]Assessing climate change impacts on pearl millet under arid and semi-arid environments using CSM-CERES-Millet model
2019
Ullah, Asmat | Ahmad, Ishfaq | Ashfaq, Ahmad | Khaliq, Tasneem | Saeed, Umer | M. Habib-ur-Rahman, | Hussain, Jamshad | Ullah, Shafqat | Hoogenboom, Gerrit
Climate change adversely affects food security all over the world, especially in developing countries where the increasing population is confronting food insecurity and malnutrition. Crop models can assist stakeholders for assessment of climate change in current and future agricultural production systems. The aim of this study was to use of system analysis approach through CSM-CERES-Millet model to quantify climate change and its impact on pearl millet under arid and semi-arid climatic conditions of Punjab, Pakistan. Calibration and evaluation of CERES-Millet were performed with the field observations for pearl millet hybrid 86M86. Mid-century (2040–2069) climate change scenarios for representative concentration pathway (RCP) 4.5 and RCP 8.5 were generated based on an ensemble of selected five general circulation models (GCMs). The model was calibrated with optimum treatment (15-cm plant spacing and 200 kg N ha⁻¹) using field observations on phenology, growth and grain yield. Thereafter, pearl millet cultivar was evaluated with remaining treatments of plant spacing and nitrogen during 2015 and 2016 in Faisalabad and Layyah. The CERES-Millet model was calibrated very well and predicted the grain yield with 1.14% error. Model valuation results showed that there was a close agreement between the observed and simulated values of grain yield with RMSE ranging from 172 to 193 kg ha⁻¹. The results of future climate scenarios revealed that there would be an increase in Tₘᵢₙ (2.8 °C and 2.9 °C, respectively, for the semi-arid and arid environment) and Tₘₐₓ (2.5 °C and 2.7 °C, respectively, for the semi-arid and arid environment) under RCP4.5. For RCP8.5, there would be an increase of 4 °C in Tₘᵢₙ for the semi-arid and arid environment and an increase of 3.7 °C and 3.9 °C in Tₘₐₓ, respectively, for the semi-arid and arid environment. The impacts of climate changes showed that pearl millet yield would be reduced by 7 to 10% under RCPs 4.5 and 8.5 in Faisalabad and 10 to 13% in Layyah under RCP 4.5 and 8.5 for mid-century. So, CSM-CERES-Millet is a useful tool in assessing the climate change impacts.
اظهر المزيد [+] اقل [-]Examining the impact of globalization in the environmental Kuznets curve hypothesis: the case of tourist destination states
2019
Akadiri, Seyi Saint | Lasisi, Taiwo Temitope | Uzuner, Gizem | Akadiri, Ada Chigozie
This paper examines the relationship between carbon emissions and international tourism growth through the channels of globalization, energy consumption, and real income via testing the environmental Kuznets curve over the periods of 1995 to 2014 for 15 selected tourism destination states that prioritized tourism as a means of maximizing economic growth. Using the panel data analysis, results confirm globalization-tourism-induced EKC hypothesis for tourist destination states. This implies international tourism growth and carbon emissions, through the channels of energy consumption, globalization, and real income, are in a long-term equilibrium relationship. International tourism and squared term of real income have an inverse significant effect on carbon emission level, while energy consumption, globalization, and real income without squared term exert positive and significant effects on carbon emission level in the long-run. Thus, globalization-tourism-induced EKC hypothesis is suggested with credible policy suggestions in the case of tourist destination states.
اظهر المزيد [+] اقل [-]Trace metal element pollution of soil and water resources caused by small-scale metallic ore mining activities: a case study from a sphalerite mine in North China
2019
Lu, Jingzhao | Lu, Hongwei | Lei, Kaiwen | Wang, Weipeng | Guan, Yanlong
Trace metal element contamination in mining areas is always a huge environmental challenge for the global mining industry. In this study, an abandoned sphalerite mine near the Yanshan Mountains was selected as subject to evaluate the soil and water contamination caused by small-scale mining. The results show that (1) Pearson correlation matrix and principal component analysis (PCA) results reveal that Zn, Cu, Cd, and Pb were greatly affected by the operation of mines, especially mineral tailings. The contents of trace metal elements decrease with the increase of the distance from the mining area. Zinc, Pb, and Cd were discovered in almost all soil samples, and Zn accounted for about 80% of pollution of the topsoil. (2) The trace element pollution levels in the topsoil of the three villages were ranked as follows: Cd > Cu > Pb~Zn. The potential ecological risk of farmland around the mine ranges from lower to higher, with Cd being the most harmful. (3) Human health risk assessment results show that trace elements in the mining area pose obvious non-carcinogenic health risks to children while the risks to adults are not equally obvious. The carcinogenic risk of Cd and Cr is within a safe range and does not pose an obvious cancer risk to the population.
اظهر المزيد [+] اقل [-]Eco-industrial zones in the context of sustainability development of urban areas
2019
Sacirovic, Selim | Ketin, Sonja | Vignjevic, Nada
Industry is one of the main activities in the city and in many cities of the world, and the dominant industrial zones are the most significant morphological forms of concentration of industrial facilities in the city and are concentrated industrial and business activity. Industrial parks combine activities related to energy and resource consumption, emissions, waste generation, economic benefits, and regional development. The focus of this work is the path of transformation between the present and the vision of a sustainable city in the future. The problem and the subject of research related to two related objects of research: the city and sustainable development. In this paper, the co-author’s industrial symbiosis parks, modern tendencies of the spatial distribution of productive activities, circular economy, to attract leading corporations and open the way for new ventures while preserving the living environment in an urban area.
اظهر المزيد [+] اقل [-]Comparative studies on endogenic stress hormones, antioxidant, biochemical and hematological status of metabolic disturbance in albino rat exposed to roundup herbicide and its active ingredient glyphosate
2019
Owagboriaye, Folarin | Dedeke, Gabriel | Ademolu, Kehinde | Olujimi, Olanrewaju | Aladesida, Adeyinka | Adeleke, Mistura
There have been growing concerns and uncertainty about reports attributing the metabolic disturbance induced by a commercial formulation of glyphosate-based herbicide to its active ingredient. We therefore compared the effects of Roundup Original® and its active ingredient glyphosate on some hypothalamic-pituitary-adrenal (HPA) hormones and oxidative stress markers, biochemical and hematological profiles in 56 adult male albino rats randomly assigned to seven treatments of eight rats per treatment. The rats were orally exposed to Roundup Original® and its active ingredient daily at 3.6 mg/kg body weight (bw), 50.4 and 248.4 mg/kgbw of glyphosate equivalent concentrations for 12 weeks, while control treatment received distilled water. Serum concentrations of corticosterone, adrenocorticotropic hormone, aldosterone and concentration of oxidative stress marker, biochemical and hematological profiles in the blood were determined. Concentrations of corticosterone and aldosterone were significantly higher (p < 0.05) in rats treated with Roundup in a dose-dependent manner. Reduced glutathione concentration, catalase, and butyrylcholinesterase activities reduced significantly in rats treated with Roundup relative to those treated with the active ingredient. Lipid peroxidation was observed in rats treated with Roundup. Biochemical and hematological profiles of rats treated with Roundup were significantly altered (p < 0.05). However, significant changes in only acid phosphatase, lactase dehydrogenase, bilirubin, and white blood cells in rats treated with the active ingredient at 50.4 mg/kg were observed. The severe metabolic disturbance and stress observed in rats treated with the commercial formulation of Roundup herbicide may not be associated with the mild changes induced by the active ingredient.
اظهر المزيد [+] اقل [-]Thermodynamic and kinetic insights into plant-mediated detoxification of lead, cadmium, and chromium from aqueous solutions by chemically modified Salvia moorcroftiana leaves
2019
Salman, Syed Muhammad | Ali, Asad | Khan, Behramand | Iqbal, Mehmood | Alamzeb, Muhammad
Thermodynamic and kinetic aspects for the biosorptive removal of Pb, Cd, and Cr metals from water using Chemically Modified Leaves of Salvia moorcroftiana (CMSML) were determined. Different parameters including pH, temperature, metal’s initial concentration, biomass dosage, and contact time were optimized. Optimum biosorptions of Pb, Cd, and Cr were attained at pH values of 6.0, 7.0, and 3.0 respectively. Batch experiments showed maximum removal of both Pb and Cd at 40 °C and that of Cr at 30 °C. Biosorption capability of CMSML was observed to decrease with raising temperature. Optimal equilibrium times for Pb, Cd, and Cr uptake were 120, 60, and 120 min respectively. Based on the values of regression correlation coefficients (R²), the current data is explained better by applying Langmuir isotherms than the Freundlich model. Maximum biosorbent capabilities (qₘₐₓ) for Pb, Cd, and Cr were approximately 270.27, 100.00, and 93.45 mg/g respectively. Thermodynamically, removal of all the three metal ions was shown to be exothermic and spontaneous.
اظهر المزيد [+] اقل [-]