Refine search
Results 5631-5640 of 6,489
Toxic effects of a mancozeb-containing commercial formulation at environmental relevant concentrations on zebrafish embryonic development Full text
2020
Vieira, Raquel | Venâncio, Carlos A. S. | Félix, Luís M.
The toxicological knowledge of mancozeb (MZ)-containing commercial formulations on non-target species is scarce and limited. Therefore, the objective of this work was to represent a realistic application scenario by evaluating the toxicity of environmental relevant and higher concentrations of a commercial formulation of MZ using zebrafish embryos. Following determination of the 96-h LC₅₀ value, the embryos at the blastula stage (~ 2 h post-fertilisation, hpf) were exposed to 0.5, 5, and 50 μg L⁻¹ of the active ingredient (~ 40× lower than the 96-h LC₅₀). During the exposure period (96 h), lethal, sublethal, and teratogenic parameters, as well as behaviour analysis, at 120 hpf, were assayed. Biochemical parameters such as oxidative stress–linked enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR)), reactive oxygen species (ROS) levels, and glutathione levels (GSH and GSSG), as well as the activity of degradation (glutathione S-transferase (GST) and carboxylesterase (CarE)), neurotransmission (acetylcholinesterase (AChE)), and anaerobic respiration (lactate dehydrogenase (LDH))–related enzymes, were analysed at the end of the exposure period. Exposed embryos showed a marked decrease in the hatching rate and many malformations (cardiac and yolk sac oedema and spinal torsions), with a higher prevalence at the highest concentration. A dose-dependent decreased locomotor activity and a response to an aversive stimulus, as well as a light-dark transition decline, were observed at environmental relevant concentrations. Furthermore, the activities of SOD and GR increased while the activity of GST, AChE, and MDA contents decreased. Taken together, the involvement of mancozeb metabolites and the generation of ROS are suggested as responsible for the developmental phenotypes. While further studies are needed to fully support the hypothesis presented, the potential cumulative effects of mancozeb-containing formulations and its metabolites could represent an environmental risk which should not be disregarded.
Show more [+] Less [-]Leaching of metal(loid)s from ashes of spent sorbent and stabilisation effect of calcium-rich additives Full text
2020
Kasiuliene, Alfreda | Carabante, Ivan | Sefidari, Hamid | Öhman, Marcus | Bhattacharya, Prosun | Kumpiene, Jurate
Contaminated water with multiple contaminants, including As, Cr, Cu and Zn, was treated with a sorbent prepared by coating peat with Fe oxides. Because As has a relatively little explored market, the regeneration of the spent sorbent was not feasible. Meanwhile, the disposal of As wastes in landfills can cause landfill leachate treatment problems. Under the reducing conditions prevailing at landfills, As(V) is reduced to As(III), which is a toxic and more mobile form. In this study, incineration was explored as a management option to treat the spent sorbent that was loaded with As, Cr, Cu and Zn. The first objective of this study was to evaluate the leaching of these metal(loid)s from the ashes and compare it with the leaching from the spent sorbents before incineration. The second objective was to evaluate the leaching behaviour when the spent sorbent was co-incinerated with a Ca-rich additive (lime). To achieve these objectives, the obtained ashes were subjected to leaching tests, sequential extraction, and X-ray diffraction analyses. After the incineration, the ash content ranged from 9 to 19% of the initial mass of the spent sorbents. The leaching of As, Cu and Zn decreased compared with that from the spent sorbents before the thermal treatment because of the high incineration temperatures and/or co-incineration with lime. However, the leaching of Cr increased, which would hinder the disposal of the obtained ashes in a landfill because the limit value for disposal at a landfill for hazardous wastes was exceeded by 50 times. However, co-incineration with 10 wt% lime significantly decreased the leaching of Cr as a result of the formation of water-insoluble Ca-Cr compounds.
Show more [+] Less [-]Comprehensive pollution monitoring of the Egyptian Red Sea coast by using the environmental indicators Full text
2020
Nour, Hamdy El Sayed | Nouh, El Said
The environmental pollution indicators and multivariate statistical analysis were used to evaluate the potential ecological risk and the contamination of Fe, Mn, Zn, Ni, Pb, Cu, Cd, and Co in surface sediments of the Egyptian Red Sea coast. The results revealed that the studied area suffers from high contamination of certain metals such as the Hurghada area (Pb, Cd, Zn, Ni, and Cu), Quseir City area (Cd, Co, Pb, and Ni), and Safaga and Marsa Alam areas (Cd and Pb). Enrichment factor and principal components analysis reported that the pollution sources of Fe, Mn, and Co are related to natural weathering process while Cu, Zn, Ni, and Pb are related to anthropogenic sources as landfill, plastic rubbish, fishing boats, phosphate operations, and tourist activities. Moreover, Co and Cd metals can come from both of natural and anthropogenic sources. The average concentrations of Cd, Cu, Zn, Pb, Ni, and Co in sediments of the Egyptian Red Sea coast are higher than those in the coasts of the Red Sea (Saudi Arabia), Mediterranean Sea (Egypt and Libya), Bengal bay (India), and the Caspian Sea (Russia). However, the studied metal content is lower than the sediment quality guideline values except for Cd.
Show more [+] Less [-]The link between carbon emissions, renewable energy consumption, and economic growth: a heterogeneous panel evidence from West Africa Full text
2020
Musah, Mohammed | Kong, Yusheng | Mensah, Isaac Adjei | Antwi, Stephen Kwadwo | Donkor, Mary
This study examined the nexus between carbon emissions, renewable energy consumption, and the economic growth of West African countries for the period 1990 to 2018. To be able to uncover reliable and valid findings, more robust panel estimation methods were employed for the study. From the heterogeneity and cross-sectional dependence tests, the study’s panels were heterogeneous and cross-sectionally dependent. Also, all the series were non-stationary at levels, but gained stationarity after first difference. Further, the Fisher test and the Westerlund and Edgerton bootstrap test found the variables to be cointegrated in the long run. The CCEMG and the DCCEMG estimators were used to explore the long-run equilibrium relationship amid the series, and from the results of the whole sample, CO₂ emissions and renewable energy consumption (REC) had no vital influence on economic growth (GDP) in both estimators. However, the results were a bit different in the sub-panels. Also from the whole sample, control variables urbanization (URB) and population growth (POP) had no material effect on GDP in both estimators. The results were, however, dissimilar in the sub-panels. Finally, the Dumitrescu-Hurlin test was employed to examine the causalities amid the series, and the results were diverse in the various panels. Policy recommendations are further discussed.
Show more [+] Less [-]Combining forward with recurrent neural networks for hourly air quality prediction in Northwest of China Full text
2020
Zhao, Zhili | Qin, Jian | He, Zhaoshuang | Li, Huan | Yang, Yi | Zhang, Ruisheng
Data-driven statistical air quality prediction methods usually build models fast with moderate accuracy and have been studied a lot in recent years. However, due to the complexity of air quality prediction which usually involves multiple factors, such as meteorological, spatial, and temporal properties, it is still a challenge to propose a model with required accuracy. In this paper, we propose a hybrid ensemble model CERL to exploit the merits of both forward neural networks and recurrent neural networks that are designed for handling time serial data to predict air quality hourly. Measured air pollutant factors including Air Quality Index (AQI), PM₂.₅, PM₁₀, CO, SO₂, NO₂, and O₃ are used as input to predict air quality from 1 to 8 h ahead. Based on the air quality prediction evaluation in Lanzhou and Xi’an, which are two important provincial capitals in Northwest China, CERL provides better performance over other baseline models. Moreover, as the step length increases, CERL has more obvious improvement. For example, the improvements of CERL in the 1-step, 3-step, 5-step, and 8-step prediction for PM₂.₅ in Lanzhou are 1.82%, 8.01%, 9.98%, and 20.03%, respectively. The superiority of CERL is also proved by a hypothesis Diebold Mariano test with level of significance 5%.
Show more [+] Less [-]Effects of vitamin A and vitamin E on attenuation of amphotericin B-induced side effects on kidney and liver of male Wistar rats Full text
2020
Salehzadeh, Aref | Salehzadeh, Alireza | Maghsood, Amir-Hossein | Heidarisasan, Shirin | Taheri-Azandaryan, Masoumeh | Ghafourikhosroshahi, Abolfazl | Abbasalipourkabir, Roghayeh
Despite the fact that amphotericin B (AmB) is currently considered as the first choice for treatment of visceral leishmaniasis, it is associated with some side effects. This study was designed to investigate the protective effects of vitamins A and E against amphotericin B-induced adverse effects in the kidney and liver of rat. Thirty male Wistar rats aged 7–8 weeks and weighing around 200 g were randomly divided into five groups, each one containing six rats. The first to fifth groups received olive oil as the control groups, AmB, AmB + vitamin A, AmB + vitamin E, and AmB + vitamins A + E, respectively. Rats received vitamins by gavage (vitamin A, 1000 IU/kg and vitamin E, 100 IU/kg) and amphotericin B by injections (5.5 mg/kg body weight). The treatment was constantly continued for 5 days and days 7 and 21. At the end of the study, serum level of TAC, TOS, MDA, liver enzyme activity (ALT, AST, ALP, LDH), renal factors (urea, uric acid, and creatinine), lipid profile as well as histopathological changes of the liver and kidney were investigated. AmB significantly increased serum level of creatinine, urea, uric acid, ALP, TOS, MDA, and kidney and renal tissue damage (p < 0.05). Supplementation AmB with vitamins A and E alone or combination improved oxidative stress status, liver and renal tissue structure, and functional parameters and serum lipid profile. This study highlighted the effects of vitamin A and vitamin E on attenuation of amphotericin B-induced side effects on the kidney and liver of male Wistar rats. Combination of the two vitamins is more effective than either alone improving the oxidative stress status, serum lipid profile, or liver and renal tissue structure and functional parameters.
Show more [+] Less [-]Evaluation of inorganic contaminants emitted from automobiles and dynamics in soil, dust, and vegetations from major highways in Pakistan Full text
2020
Anwar, Sumera | Naz, Aneela | Ashraf, M Yasin | Malik, Arif
The deposition of toxic metals in the ecosystem contributes to the exposure and bioaccumulation of metals in the food chain, thus affecting human health. This study aimed to access the distribution of metal pollution emitted from automobiles in the dust, soil, and plant samples collected from the roadsides of national highways. Furthermore, metals were also determined in fuels and vehicular emissions. High contents of Pb, Cd, Cr, Cu, Fe, Mn, and Zn were found in roadsides as compared to control (35 km away from roads). The comparison among plants indicated that Calotropis procera and Rumex dentatus contained significantly higher metals than other plants. The concentrations of Pb, Cd, Cr, and Fe in plants were above the safe limits of the WHO/FAO. Significant and positive correlations were found between Cr, Cu, Fe, Pb, and Zn in the dust and soil samples and Cd and Cr in dust and plants. According to the results of the PCA analysis, all metals formed the first two components explaining 89.5% of the total variance. The source of these metals was attributed to automobile exhaust and dust depositions. The findings of the present study suggest that roadside plants are heavily infested with heavy metals due to vehicular smoke pollution, so the consumption of vegetation facing vehicular pollution may lead to certain physiological disorders and diseases. Graphical abstract
Show more [+] Less [-]Antibacterial and cytotoxic activities of cerium oxide nanoparticles prepared by laser ablation in liquid Full text
2020
Abid, Suhad A. | Taha, Ali A. | Ismail, Raid A. | Mohsin, Mayyadah H.
In this work, we have prepared cerium oxide (CeO₂) nanoparticles (NPs) by laser ablation in water at different laser energies. The structural and optical properties of synthesized nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectroscopy, energy dispersive X-ray (EDX), and UV-Vis absorption. XRD results confirmed that the synthesized cerium oxide NPs were crystalline in nature with cubic structure. SEM investigations show that the nanoparticles having a spherical shape with diameter ranged from 26 to 37 nm depending on the laser energy. The antibacterial activity and minimal inhibition concentration of synthesized CeO₂ NPs against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa were examined. Bacterial adhesion test of cerium oxide NPs was also determined under different incubation temperatures. Cytotoxicity of CeO₂ NP effect against the human throat cancer was studied. The cytotoxicity effect of CeO₂ NPs synthesized at 160 mJ on the cancer cells caused a free radical releasing which causing oxidative stress. The cytotoxicity effects of ceria NPs against human throat cancer (RD rhabdomyosarcoma cell line) and mouse fibroblast L cell (L20B cell line) growth were 33% and 13%, respectively.
Show more [+] Less [-]Effects of MoO3 and CeO2 doping on the decomposition and reactivity of NH4HSO4 on V2O5/TiO2 catalysts Full text
2020
Xu, Wenqing | Gao, Lei | Yang, Yang | Zhu, Tingyu | Qi, Guisheng
The deposition of NH₄HSO₄ on catalysts is one of the key issues for selective catalytic reduction of NOₓ. In this study, NH₄HSO₄ was preloaded on catalysts, and the effects of MoO₃ and CeO₂ doping on the decomposition and reactivity of NH₄HSO₄ on V₂O₅/TiO₂ catalysts are studied. The results show that the introduction of MoO₃ and CeO₂ significantly promoted NOₓ conversion on the V₂O₅/TiO₂ catalysts. Doping with MoO₃ could effectively enhance the S and H₂O resistance of the catalysts. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicate that it is the strong chemical interactions between NH₄HSO₄ and the catalysts that are adverse to the decomposition of NH₄HSO₄. However, doping with MoO₃ apparently inhibits these interactions, which significantly decrease the decomposition temperature of NH₄HSO₄. In situ FTIR experiments show that the NH₄⁺ in preloaded NH₄HSO₄ could react with gaseous NO on catalysts, and doping with MoO₃ could facilitate the reaction rate.
Show more [+] Less [-]Phthalate esters (PAEs) in soil and vegetables in solar greenhouses irrigated with reclaimed water Full text
2020
Li, Yan | Huang, Guanhua | Zhang, Lei | Gu, Hua | Lou, Chunhua | Zhang, Hang | Liu, Honglu
Phthalate esters (PAEs) in environments have become a public concern due to their harmful impacts on human and environments, and waste/reclaimed water irrigation maybe one of their sources in agricultural soil. A field experiment was setup to analyze the impacts of reclaimed water irrigation on levels of PAEs in vegetables and topsoil in solar greenhouse on the North China Plain during 2015 and 2016. There were 6 varieties of vegetables. For each variety, there were three irrigation treatments, including groundwater irrigation, reclaimed water irrigation, and alternative irrigation with groundwater and reclaimed water (1:1, v/v). The results show that the levels of the 6 PAEs in soil and vegetables varied between 0.73 and 9.48 mg/kg and 1.89 and 6.35 mg/kg, respectively. There were no significant differences for PAE concentrations among these different treatments at each vegetable harvest (p > 0.05). For both soil and vegetable samples, Di-n-butyl phthalate (DnBP) and Di (2-ethylhexyl) phthalate (DEHP) were the most dominant PAEs, with contents of 0.39–4.43 mg/kg and 0.25–6.31 mg/kg, respectively, contributing12.5–74.60% and 21.24–76.48% of the total 6 PAEs, respectively. The contents of DnBP and dimethyl phthalate (DMP) in topsoil were higher than the suggested allowable values, while the concentration of each individual PAE in topsoil was lower than the suggested cleanup objectives. The levels of 6 PAEs, DEHP, and DnBP in vegetables were below the reference doses. The yields of eggplant, cauliflower, bean, cabbage, cucumber, and carrot were 64.4–67.0 t/ha, 10.9–13.0 t/ha, 12.3–15.1 t/ha, 17.3–17.5 t/ha, 43.9–44.5 t/ha, and 19.0–22.9 t/ha, respectively, and no significant differences were found among these different treatments for each kind of vegetable. The bioaccumulation factors (BCFs) of 6 PAEs in vegetable samples were 0.43–5.79 and the corresponding values for each PAE were 0.00–27.32, respectively. The BCFs of butyl benzyl phthalate were the greatest (with a mean of 9.28), followed by DEHP (with a mean of 3.03) and DMP (with a mean of 1.90). In one word, the reclaimed water in this study did not affect the vegetable yields obviously. PAE levels in soil and vegetables irrigated with reclaimed water were in the acceptable range. Considering the difference of reclaimed water quality of Sewage Treatment Plants in different areas, so more reclaimed water from different areas is needed to assess the impacts of reclaimed water irrigation on PAE contamination in soil and vegetables.
Show more [+] Less [-]