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Modelling environmental degradation in South Africa: the effects of energy consumption, democracy, and globalization using innovation accounting tests Texte intégral
2020
Usman, Ojonugwa | Olanipekun, Ifedolapo O. | Iorember, Paul Terhemba | Abu-Goodman, Maryam
This study investigates the effects of energy consumption, democracy and globalization on environmental degradation in the context of the environmental Kuznets curve (EKC) for South Africa between 1971 and 2014. To this end, the study applies the combined Bayer-Hanck cointegration test and the fully modified ordinary least squares (FM-OLS) estimation approach. The empirical results confirm the presence of cointegration among the variables, and thus validate the EKC hypothesis for South Africa. In addition, while energy consumption increases environmental degradation, the effect of democracy is positively insignificant. The finding also suggests that globalization condenses environmental degradation. The results of the long-run causal relationship divulge that economic growth, energy consumption, democracy and globalization Granger-cause environmental degradation. The results also find causality running from CO₂ emissions, economic growth, democracy and globalization to energy consumption. In the short run, a causality is found running from globalization to CO₂ emissions, energy consumption to CO₂ emissions and globalization to energy consumption. In addition, economic growth is said to Granger-cause democracy while democracy Granger-causes CO₂ emissions. These results are validated by the innovation accounting tests.
Afficher plus [+] Moins [-]Correction to: Investigation of organic material self-heating in oxygen-depleted condition within a coal-waste dump in Upper Silesia Coal Basin, Poland Texte intégral
2020
Nádudvari, Ádám | Fabiańska, Monika J. | Misz-Kennan, Magdalena | Ciesielczuk, Justyna | Kowalski, Adam
The original publication of this paper contains a mistake.
Afficher plus [+] Moins [-]Methanolic extract of Ephedra alata ameliorates cisplatin-induced nephrotoxicity and hepatotoxicity through reducing oxidative stress and genotoxicity Texte intégral
2020
Sioud, Fairouz | Ben Toumia, Imene | Lahmer, Aida | Khlifi, Rihab | Dhaouefi, Zaineb | Maatouk, Mouna | Ghedira, Kamel | Chekir-Ghedira, Leila
Cisplatin (CP) is a powerful anticancer agent used in the treatment of a diverse type of cancers. Oxidative stress is one of the most important side effects limiting the use of cisplatin. The protective effects of methanolic extract (ME) and ephedrine (EP), major compound, of Ephedra alata on CP-induced damages were here assessed. Treatment with CP-induced nephrotoxicity and hepatotoxicity characterized by biochemical alterations. In fact, using CP reduced significantly glutathione (GSH) levels, enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and increased malondialdehyde (MDA) content. Nonetheless, CP-treatment induced DNA damage at renal, hepatic, and blood cells and increased interferon gamma (IFNγ) level in serum. Co-treatments of mice with ME normalized relative kidney/body weight, restored biochemical and oxidative stress parameters, reduced DNA damage and IFNγ level. In conclusion, ME exhibited the best protective effect against CP damage compared with ephedrine. This is could be attributed to the presence of polysaccharides, organic acids, flavonoids, and tannins in addition to ephedrine alkaloids. These compounds were reported to play a major role in inhibiting and scavenging free radicals, providing an effective protection against CP- induced oxidative damage. Graphical abstract
Afficher plus [+] Moins [-]Evaluating the toxicity of polyurethane during marine clay stabilisation Texte intégral
2020
Saleh, Samaila | Ahmad, Kamarudin | Mohd Yunus, Nor Zurairahetty | Hezmi, Muhammad Azril
In civil engineering, many geotechnical and forensic projects employ polyurethane (PU) for ground improvement, and the results have shown to be effective in terms of time and cost savings. However, similar to many other chemical stabilisers, the use of PU for soil stabilisation may have environmental repercussions. Therefore, this paper utilised a toxicity characteristic leaching procedure (TCLP) to investigate the potential for ground contamination resulting from the application of PU for the stabilisation of marine clay. Furthermore, the hazardousness of PU during the stabilisation of marine clay was investigated by testing its reactivity, ignitability, corrosivity and physical properties. The results reveal that the quantity of heavy metals present in PU is far below the regulatory limits. The results further confirm that PU is odourless and non-corrosive and that it is non-cyanide and non-sulphide-bearing. However, PU is capable of igniting. Overall, the potential application of PU for ground improvement is promising due to its environmental friendliness.
Afficher plus [+] Moins [-]Pollution evaluation, spatial distribution, and source apportionment of trace metals around coal mines soil: the case study of eastern India Texte intégral
2020
Siddiqui, Azeem Uddin | Jain, Manish Kumar | Masto, Reginald Ebhin
The degradation of land by trace metals contamination around coal mining areas is a serious environmental issue, and therefore, it is necessary to have detailed information about the pollution caused by them and their sources. The objective of the work was to study the impact of trace metals (e.g., Cd, Co, Ni, Cr, Zn, Pb, and Cu) on the soil of Jharia coalfield to analyze their sources, contamination level, and their spatial distribution. The present values of the trace metals were compared by their natural background values which were then analyzed on the scale of the Potential Ecological Risk Index (PERI) and by Improved Nemerow Index (Lₙₘ). The results of spatial distribution revealed that the majority of the soil in Jharia coalfield is moderately contaminated, a small portion of it is slightly contaminated, and altogether at moderate ecological risk due to trace metals. Multivariate statistical techniques including Principal component analysis, Cluster analysis, and Pearson’s correlation evaluated that Cu, Ni, Zn, Co, and Cr in the soil samples had the same source which is coal mining; Pb and Cd were from multiple sources. The spatial distribution maps of trace metals present in the soil of Jharia coalfield were generated using Radial basis function an interpolation method.
Afficher plus [+] Moins [-]Effect of cooking on arsenic concentration in rice Texte intégral
2020
Atiaga, Oliva | Nunes, Luis M. | Otero, Xosé L.
This study assessed the effect of rinsing and boiling on total content of As (tAs) and of its inorganic and organic forms in different types of rice (polished and brown) from Spain and Ecuador. Rice was subjected to five different treatments. The results showed that the treatment consisting of three grain rinsing cycles followed by boiling in excess water showed a significant decrease in tAs content compared with raw rice. Regarding As species, it is worth noting that the different treatments significantly reduced the content of the most toxic forms of As. The estimated lifetime health risks indicate that pre-rinsing alone can reduce the risk by 50%, while combining it with discarding excess water can reduce the risk by 83%; therefore, the latter would be the preferable method.
Afficher plus [+] Moins [-]Drawing the baseline of trace element levels in the vulnerable Mediterranean osprey Pandion haliaetus: variations by breeding location, habitats, and egg components Texte intégral
2020
Monti, Flavio | Bianchi, Nicola | Sforzi, Andrea | Leonzio, Claudio | Ancora, Stefania
Due to its peculiarity to accumulate environmental contaminants, the osprey Pandion haliaetus is a sentinel species for the biomonitoring of contaminants in aquatic ecosystems. Despite this, no information on trace element concentration exists for the Mediterranean area, where relict and vulnerable osprey populations exist. We evaluated the geographical patterns of heavy metals and selenium in osprey eggs from three different populations of the Mediterranean basin (Balearic Islands, Corsica, and Tuscany), to identify any possible contaminant sources. Pattern of metal concentration followed the order: Fe > Zn > Cu > Se > Hg > Pb > Cd. Differences in contaminant concentrations between habitats and among egg components were found. Egg content and inner membrane showed higher mercury levels (1.06 ± 0.89 and 0.67 ± 0.62 mg/kg dw, respectively) than those recorded in the eggshell. Mercury concentration was ca. two times higher in marine than in wetland samples, and even higher (3.6 times) when referred to the eggshell. Cu, Fe, Zn, and Se had higher concentration in the inner membrane. We stress how the choice of the biological material can have significant implications for the correct evaluation of contamination. Our study represents a first regional scale survey for the vulnerable Mediterranean osprey populations and provides baseline data for their long-term biomonitoring.
Afficher plus [+] Moins [-]Salivary flow rates and buffer capacity and its relationship with oral health status: a cross-sectional study on crack-cocaine-addicted males Texte intégral
2020
Araujo, Nara Santos | das Graças Alonso Oliveira, Maria | Neto, Antenor Vieira Borges | de Oliveira Lima Arsati, Ynara Bosco | dos Santos, Jean Nunes | Cury, Patricia Ramos
This cross-sectional study evaluated the saliva profile in crack-cocaine-addicted males and its relationship with dental caries, periodontal disease, and oral mucosal lesion (OML) using 148 adult male volunteers (37 addicted; 111 non-addicted) at the School of Dentistry, Federal University of Bahia. Data on decayed, missing and filled teeth (DMFT), periodontal disease and OML were collected from the clinical examination of the participants. Samples were analysed for the salivary flow rate (SFR) of unstimulated and wax-stimulated whole saliva and the saliva buffer capacity. Bivariate and regression analyses were conducted to assess the salivary profile and its association with the oral status of addicted participants (α = 0.05). The mean buffer capacity of stimulated saliva was significantly lower in the addicted participants (pH 5.2 ± 1.7) than in the non-addicted group (pH 5.8 ± 1.3, p = 0.03). In the addicted group, OML was associated with a stimulated SFR < 1.0 mL/min (OR = 11.98, 95% CI = 1.30–27.10, p = 0.04). The DMFT index and periodontal disease were not associated with the salivary profile, but with older age (OR = 7.20, 95% CI = 1.51–31.14, p = 0.01) and lower education levels (OR = 24.00, 95% CI = 1.68–341.00, p = 0.02), respectively. In conclusion, addiction was associated with the lower buffer capacity of stimulated saliva, and OML was associated with lower-stimulated salivary flow rate. Periodontal disease or DMFT was not associated with salivary factors in addicted males. Therapy approaches dealing with saliva status may be important for use with addicted males to reduce OMLs.
Afficher plus [+] Moins [-]Optimization and economical study of electro-coagulation unit using CCD to treat real graywater and its reuse potential Texte intégral
2020
Bajpai, Mukul | Singh Katoch, Surjit | Singh, Manjari
The reclamation of graywater for non-potable purposes has attained utmost importance, particularly in developing nations. The present research aimed to evaluate the optimal condition of electro-coagulation system in treatment of graywater and its reuse. Moreover, the study also evaluates the impact of major operating parameters on pollutant removal and anode dissolution. To achieve this, two-factor (voltage potential and time) and 5-level (− 1, − 0.5, 0, + 0.5, and + 1) full factorial design, based on response surface methodology (RSM) has been executed for the actual design. The data were acquired after conducting 20 experiments, as suggested by RSM (response surface methodology). Design Expert 12.0.8.0 software has been used to design mathematical model to obtain optimum condition (14 V and 47 min) at pH of 7.35, which provides experimental removal efficiency (75.6% chemical oxygen demand, 78.7% total dissolved solids, 93.4% turbidity, and 63.2% chloride) with minimal electrode consumption of 1.38 mg L⁻¹. Adequacy of the model developed has been verified by ANOVA. The operating cost of treating graywater at the optimized condition obtained as 0.7 US$/kg COD.
Afficher plus [+] Moins [-]Evaluating the use of synchrotron X-ray spectroscopy in investigating brominated flame retardants in indoor dust Texte intégral
2020
Blanchard, Peter | Babichuk, Nicole | Sarkar, Atanu
Brominated flame retardants (BFRs) are commonly used in consumer products and they shed off these products and eventually build up in household dust. Polybrominated diphenyl ethers (PBDEs), in particular, are known endocrine-disrupting chemicals affecting various hormone syntheses. Portable X-ray fluorescence spectroscopy (XRF) is the most common non-destructive method in identifying BFRs in environmental samples. However, the method is insensitive to bromine speciation. Synchrotron-based XRF has been shown to have very low detection limits (< 1 μg/g) that is suitable for detecting BFRs and can be combined with X-ray absorption near-edge spectroscopy (XANES) to identify the bromine species present in the household dust. Twenty indoor dust samples were collected from rural homes in Newfoundland (Canada) to assess the use of synchrotron-based techniques to identify BFRs. Synchrotron-based XRF analysis identified bromine in all the samples, with concentrations ranging from 2–19 μg/g. XANES analysis identified organic-based bromine species in several samples that are likely BFRs based on the spectral line shape. The accuracy of using XANES to identify BFRs is highly dependent on the source and size of the dust samples. Therefore, for future research, it is important to take into account the sources of dust sample and to focus on fine dust particles.
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