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Spatio-temporal variability of meteorological drought over India with footprints on agricultural production Texte intégral
2021
dar, Junaid | dar, Abdul Qayoom
The perception of spatio-temporal variability of drought is important in concerning the food security of a country. The native aim of this study is to extract the spatio-temporal variability of drought over India with implications on agriculture. We have opted for SPI-3 as the primary index for drought quantification. The spatio-temporal variability of SPI-3 is evaluated through empirical orthogonal functional (EOF) analysis to extract the prominent patterns of drought variability over the study region. The first two dominant patterns of SPI-3 explain (38%) the total variability and are mainly influenced by global teleconnections. The EOF patterns while subjected to spectrum analysis depict that the first mode shows 7.7 years of cycle and the second mode shows 2.6 years of the cycle. On seeing the interference of El Nino Southern Oscillation (ENSO) on drought, we found that drought years are mainly influenced by ENSO with the same periodicity (2–7 years/cycle) as that of EOF patterns. The dynamics of drought show that the persistence of high pressure along East and West Asia during drought years has declined the monsoon activity over India leading to a shortfall of rainfall in monsoon months. On the other hand, we have found that the drought years have drawn implications on agricultural production by stifling the total annual production of most of the drought years. This research would have a wide range of applications in forecasting extreme events in India, allowing for better preparation and management of the water resource system during droughts.
Afficher plus [+] Moins [-]Bone Char from an Invasive Aquatic Specie as a Green Adsorbent for Fluoride Removal in Drinking Water Texte intégral
2021
Cruz-Briano, Sergio Armando | Medellín-Castillo, Nahum Andrés | Torres Dosal, Arturo | Leyva Ramos, Roberto | Moreno-Pirajan, Juan Carlos | Giraldo-Gutiérrez, Liliana | Díaz-Flores, Paola Elizabeth | Reyes López, Simón Yobanny | Ocampo-Pérez, Raúl
In this study, bone chars were obtained from an alien aquatic species “devilfish” bones by pyrolysis of 500–800 °C. Bone chars were evaluated as a sustainable adsorbent of fluoride, and it was found pyrolyzed bone char at 500 °C adsorbed the most amount of fluoride. Thermodynamic parameters of fluoride adsorption on devilfish bone chars were estimated as ΔH° = 7.213 kJ mol⁻¹, ΔG° = 23.61 kJ mol⁻¹, and ΔS° = 103.4 J mol⁻¹ K⁻¹ indicating that adsorption is endothermic, spontaneous, and with a great affinity of fluoride on bone char. The fluoride desorption study showed that fluoride is desorbed from the material of 0.24 to 20.06%, so the adsorption is considered to be partly reversible. The regeneration of the bone char at 400, 500, and 600 °C was studied, and it was noted that its adsorption capacity decreases slightly, so it could be considered appropriate for the use in water treatment technologies. Adsorption of fluorides from drinking well water of a rural community with dental fluorosis problems and high levels of fluoride in water revealed that by increasing the amount of the bone char of 0.05 to 0.8 g, the disposal of fluoride increases from 69.1 to 98.7%. Lastly, it was established that the bone char synthesized from devilfish is a low-cost, viable, sustainable material to remove fluorides from water and represents an environmental management strategy of this alien species.
Afficher plus [+] Moins [-]How do trade and economic growth impact environmental degradation? New evidence and policy implications from the ARDL approach Texte intégral
2021
Asiedu, Benjamin Ampomah | Gyamfi, Bright A. | Oteng, Evans
Due to various environmental degradation and natural resource depletion around the world, researchers’ and policymakers’ attention has turned to what causes environmental degradation. The pursuit of a healthy environment has become a global challenge, a problem that affects more than one nation. Climate change is causing severe weather conditions in every world, disrupting economies and affecting the lives of many people. Hence, the study analyzes how trade and economic growth impact environmental degradation in Belgium, the USA, and Canada using panel data from 1995 to 2016. The study utilized the autoregressive distributed lag approach to provide new evidence and policy implications. The outcome confirmed the presence of cointegration among the selected variables. However, it was observed that economic growth decreases environmental degradation in the long run while trade openness shows a positively insignificant relationship with carbon emission. Nevertheless, a positive short-run relationship was observed between economic growth and carbon emissions whereas a negatively insignificant relationship was observed for trade and carbon emission. The findings prompted policy implications that more trading could be done between the countries. When countries trade more, their economies will flourish, ensuring global prosperity and minimizing environmental degradation.
Afficher plus [+] Moins [-]Green synthesis of recyclable iron oxide nanoparticles using Spirulina platensis microalgae for adsorptive removal of cationic and anionic dyes Texte intégral
2021
Shalaby, Shymaa M. | Madkour, Fedekar F. | El-Kassas, Hala Y | Mohamed, Adel A. | Elgarahy, Ahmed M.
Globally, organic dyes are major constituents in wastewater effluents due to their large-scale industrial applications. These persistent pollutants adversely impact the public health of different living entities. Thus, wastewater remediation has become an indispensable necessity. Herein, we greenly synthesized iron oxide nanoparticles (SP-IONPs) using Spirulina platensis microalgae to remove cationic crystal violet (CV) and anionic methyl orange (MO) dyes from their aqueous solution. The engineered sorbent was thoroughly scrutinized by different characterization techniques of FT-IR, BET surface area, SEM, EDX, TEM, VSM, UV/Vis spectroscopy, and pHPZC measurement. The proficiency of SP-IONPs was methodically appraised for its sorptive performance towards the target CV and MO dyes under variable technological parameters (batch scenario). Collectively, the outlined results inferred an amazing efficacy characterized to the SP-IONPs sorbent for the expulsion of relevant dyes from the aqueous media. Regarding the dynamic static sorption data, the kinetics profile was ascribed to the pseudo-second order model, whereas sorption isotherm was quantitatively dominated by the Langmuir theory with maximum sorption capacities of 256.4 mg g⁻¹ and 270.2 mg g⁻¹ for CV and MO, respectively. Thermodynamics findings conformed the endothermic nature of sorption process. Repeatability of the spent sorbent was successfully emphasized for 5 times of sorption/desorption cycles. The productive sorbent admirably sequestered CV and MO dyes from spiked tap water. The potency of SP-IONPs as color collecting material from real dyeing effluents was achieved.
Afficher plus [+] Moins [-]Modelling the symmetrical and asymmetrical effects of global oil prices on local food prices: A MENA region application Texte intégral
2021
Hadj cherif, Houda | Chen, Zhenling | Ni, Guohua
This paper explores the complex nexus between the global oil prices and the food prices of the Middle East and North Africa (MENA) region during the period 2000–2020. Both linear and nonlinear models of the autoregressive distributed lag (ARDL) approach are adapted into panel data form to investigate the symmetrical and asymmetrical influence of oil prices on food prices. The key results are summarized: (i) the long-term effect of oil prices on food prices is significantly positive including both oil-exporting and oil-importing nations. The positive impact on oil exporters—due to higher oil revenues—is greater than importing nations, leading to an increased demand for food. Additionally, the effect on oil exporters is negative and significant in the short term but not significant for importers. (ii) The nonlinear ARDL panel analysis for the whole MENA sample confirms the presence of negative short-term asymmetric behaviour due to the heterogeneous response within the oil-importing and oil-exporting samples, while in the long term, the asymmetric effect is positive, indicating that food prices increase regardless of fluctuations in oil prices. (iii) The nonlinear ARDL results using time series affirm the absence of an asymmetric nexus among oil and food prices for some oil-exporting nations (including Kuwait, Saudi Arabia, United Arab Emirates) and Tunisia within the oil-importing group. However, the food prices of other countries are asymmetric to the oil price. This study provides recommendations that are useful to MENA countries to establish a stable mechanism for oil and food prices to ensure food security in the region.
Afficher plus [+] Moins [-]Ecotoxicological Assessment and Environmental Risk of the Insecticide Chlorpyrifos for Aquatic Neotropical Indicators Texte intégral
2021
Marques, Márjori Brenda Leite | Brunetti, Isabella Alves | Faleiros, Camila Aparecida | da Cruz, Claudinei | Iqbal, Hafiz M. N. | Vēlāyutan̲, T. A. | Américo-Pinheiro, Juliana Heloisa Pinê
Chlorpyrifos (CPF) is an organophosphorus insecticide detected in aquatic environments considered harmful to living beings. The aim of this research was to evaluate the ecotoxicity of CPF for neotropical aquatic organisms of distinct trophic levels (Lemna minor, Azolla caroliniana, and Wolffia brasiliensis macrophytes; Pomacea canaliculata snail; Macrobrachium acanthurus shrimp; Xiphophorus maculatus and Hyphessobrycon eques fish), to verify the risk of environmental poisoning for each organism, and to determine the best bioindicator species of aquatic contamination by the insecticide. Ecotoxicological assays were carried out with different concentrations of CPF under controlled laboratory conditions standardized for each species. IC50;7d, LC50;7d, EC50;48h, and LC50;48h values were calculated using the Trimmed Spearman Karber software with 95% confidence limits. The toxicity data were used to classify the CPF according to the ecotoxicity categories for aquatic organisms. The risk of CPF environmental poisoning was determined by the quotient method considering different environmental scenarios. The sensitivity order of neotropical aquatic organisms to chlorpyrifos was Macrobrachium acanthurus (0.002 mg L⁻¹) > Xiphophorus maculatus (0.07 mg L⁻¹) > Hyphessobrycon eques (1.65 mg L⁻¹) > Pomacea canaliculata (30.66 mg L⁻¹) > Azolla caroliniana (849.72 mg L⁻¹) > Wolffia brasiliensis (1271.63 mg L⁻¹) = Lemna minor (1299.60 mg L⁻¹). The risk of poisoning by chlorpyriphos may vary according to the environmental concentration of the insecticide and the exposed trophic level. The best bioindicator and with the greatest risk of environmental poisoning was shrimp. The difference in CPF ecotoxicity for distinct aquatic trophic levels shows the relevance of evaluating the effects of contaminants considering food chains and highlights the importance of studying these levels in environmental monitoring programs.
Afficher plus [+] Moins [-]Multiple Drug-Resistant Escherichia coli Phylogroups from the Belmont Valley Integrated Algal Pond System Texte intégral
2021
Titilawo, Yinka | Jimoh, Taobat A. | Cowan, A Keith
Escherichia coli isolates, commonly found as gut microflora in warm-blooded animals, are classified into the major phylogroups, A, B1, B2 and D, and further divided into subgroups: A0, A1, B1, B2₂, B2₃, D1 and D2. This study tracks and classifies E. coli strains along an integrated algal pond system (IAPS) during municipal sewage treatment. PCR-confirmed E. coli isolates were delineated into phylogroup by targeting genes chuA, yjaA and TSPE4.C2 using the triplex PCR assay. Antimicrobial susceptibility testing was by disk diffusion assay. A total of 120 E. coli isolates were confirmed by analysis of the uidA gene. Phylogenetic analysis revealed 57 isolates were group A with others in groups B2 (35), B1 (16) and D (12). Isolate susceptibility to antibiotics was norfloxacin > florfenicol > gatifloxacin > streptomycin > gentamicin. Nearly all isolates (117, 98%) were sulphamethoxazole- and penicillin G-resistant (115, 96%). Thus, resistance was manifest by all phylogroups and to 3–17 of drugs tested. These findings confirm presence of various multidrug-resistant E. coli phylogroups throughout the IAPS wastewater treatment process and emphasize the usefulness of multidrug resistance profiling as a tool for microbial source tracking and, with which to determine origin of faecal pollution.
Afficher plus [+] Moins [-]Gill and liver transcriptomic responses of Achirus lineatus (Neopterygii: Achiridae) exposed to water-accommodated fraction (WAF) of light crude oil reveal an onset of hypoxia-like condition Texte intégral
2021
Zamora-Briseño, Jesús Alejandro | Améndola-Pimenta, Monica | Ortega-Rosas, Daniel Antonio | Pereira-Santana, Alejandro | Hernández-Velázquez, Ioreni Margarita | González-Penagos, Carlos Eduardo | Pérez-Vega, Juan Antonio | del Río-García, Marcela | Árcega-Cabrera, Flor | Rodríguez-Canul, Rossanna
Crude oil is one of the most widespread pollutants released into the marine environment, and native species have provided useful information about the effect of crude oil pollution in marine ecosystems. We consider that the lined sole Achirus lineatus can be a useful monitor of the effect of crude oil in the Gulf of Mexico (GoM) because this flounder species has a wide distribution along the GoM, and its response to oil components is relevant. The objective of this study was to compare the transcriptomic changes in liver and gill of adults lined sole fish (Achirus lineatus) exposed to a sublethal acute concentration of water-accommodated fraction (WAF) of light crude oil for 48 h. RNA-Seq was performed to assess the transcriptional changes in both organs. A total of 1073 differentially expressed genes (DEGs) were detected in gills; 662 (61.69%) were upregulated, and 411 (38.30%) were downregulated whereas in liver, 515 DEGs; 306 (59.42%) were upregulated, and 209 (40.58%) were downregulated. Xenobiotic metabolism and redox metabolism, along with DNA repair mechanisms, were activated. The induction of hypoxia-regulated genes and the generalized regulation of multiple signaling pathways support the hypothesis that WAF exposition causes a hypoxia-like condition.
Afficher plus [+] Moins [-]A pilot application of recycled discarded RO membranes for low strength gray water reclamation Texte intégral
2021
Ahmed, Jawwad | Jamal, Yousuf
Reuse of recycled RO membranes after oxidative treatment as ultrafiltration membranes promise to bring membrane filtration at par with conventional treatment processes in terms of cost-effectiveness. Although the treatment process in which discarded RO membranes are converted into ultrafiltration membranes is well documented, limited pilot data are available for their application in different filtration applications. This research gap is felt because most commercially available RO membranes are spiral, wound while the ultrafiltration membranes commonly used for water filtration applications are hollow fiber. Pilot-scale data will help to develop performance guidelines and predict fouling characteristics of different types of feed waters. In the current paper, converted RO membranes are subjected to filtration with domestic gray water as the feed source. The results show that the converted membranes performed at par with conventional filtration while also providing a consistent filtrate turbidity of < 1 NTU. The reduction in cost and physical footprints and recycling of membranes that would otherwise have ended up in landfills are added advantages that makes this an attractive proposition for gray water filtration applications.
Afficher plus [+] Moins [-]Status of short-chain chlorinated paraffins in matrices and research gap priorities in Africa: a review Texte intégral
2021
Nevondo, Vhodaho | Okonkwo, Okechukwu Jonathan
Chlorinated paraffins (CPs) have been applied as additives in a wide range of consumer products, including polyvinyl chloride (PVC) products, mining conveyor belts, paints, sealants, adhesives and as flame retardants. Consequently, CPs have been found in many matrices. Of all the CP groups, short-chain chlorinated paraffins (SCCPs) have raised an alarming concern globally due to their toxicity, persistence and long-range transportation in the environment. As a result, SCCPs were listed in the Stockholm Convention on Persistent Organic Pollutants (POPs) in May 2017. Additionally, a limit for the presence of SCCPs in other CP mixtures was set at 1% by weight. CPs can be released into the environment throughout their life cycle; therefore, it becomes crucial to assess their effects in different matrices. Although about 199 studies on SCCP concentration in different matrices have been published in other continents; however, there are scarce/or limited studies on SCCP concentration in Africa, particularly on consumer products, landfill leachates and sediment samples. So far, published studies on SCCP concentration in the continent include SCCPs in egg samples, e-waste recycling area and indoor dust in Ghana and South Africa, despite absence of any production of SCCPs in Africa. However, there still remains a huge research gap in the continent of Africa on SCCPs. Consequently, there is a need to develop robust SCCP inventories in Africa since the Stockholm Convention has already developed guidance document in this respect. This review, therefore, examines the state of knowledge pertaining to the levels and trends of these contaminants in Africa and further provides research gaps that need to be considered in order to better understand the global scale of the contaminant.
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