Affiner votre recherche
Résultats 5831-5840 de 6,541
Assessment of heavy metals contamination and the risk of non-cancerous diseases in vegetable using electromagnetic-chemical Texte intégral
2020
Mokarram, Marzieh | Amin, Hosein | Setoodeh, Abdollah
This study seeks to assess the reaction of the eggplant (Solanum melongena L.) to soil samples contaminated. Following, cultivation, growth, and harvest, the plant samples were prepared and maximum absorption rates of heavy metals were measured in both leaf and fruit. The estimated daily intake (EDI), the target hazard quotient (THQ), and the bio-concentration factor (BCF) were measured at various intervals during the growth period of the plant. Spectral analysis was also performed to assess the reaction of target crops to heavy metals. The results showed that in the second and third stages of plant growth, the THQ values were more than 1 for infected plants with Cd, Pb, and Zn. According to results from the BCF analysis, the absorption rate in Pb, during the growth stages was relatively high, in crops contaminated by Ni was around 1 in the second and third stages, and in plants contaminated by Cd was extremely high. All crops contaminated by heavy metals showed higher reflection rates in the 400–500 and 600–700 nm range. So, using electromagnetic waves during different stages of growth, the reaction of eggplant cultivated in soil samples contaminated by heavy metals is predictable.
Afficher plus [+] Moins [-]Mercury accumulation and transformation of main leaf vegetable crops in Cambosol and Ferrosol soil in China Texte intégral
2020
Yang, Bo | Gao, Yi | Zhang, Chunxue | Zheng, Xiangqun | Li, Bo
Leaf vegetables serve as an important food for the local residents in China. This paper focuses on the uptake, accumulation, transfer, and mercury (Hg) sensitivity of leafy vegetables. Two types of soil (an alkaline Cambosol and an acid Ferrosol) and eleven species of leafy vegetable, namely, Spinach, Tung choy, Leek, Fennel, Coriander, Chinese flowering cabbage, Wuta-tsai, Pakchoi, Chicory, Crown daisy, and Lettuce, were selected to investigate their sensitivity to Hg accumulation in a greenhouse pot experiment. Three Hg concentration treatments were carried out as control (background values), low concentration (1.5 times standard value), and high concentration (2 times standard value) as adjusted by the soil pH. Hg concentrations of more than half vegetable samples grown in Cambosol (collected from Shandong Province) reached or exceeded the maximum permissible food safety levels (10 μg kg⁻¹) according to the General Standard of Contaminants in Food in China (GB 2762-2012), while only about 15% in Ferrosol (collected from Jiangxi Province). Meanwhile, Hg bio-concentration factors (BCF) in all treatments were < 1, while Hg translocation factors (TF) in most treatments were < 1. Correlation analysis among soil, root, and edible plant parts revealed that the principal source of Hg in leafy vegetables was most likely from Hg-contaminated soils. Species sensitivity distribution (SSD) models were constructed and their simulated curves indicated that sensitivity to Hg was highest in Pakchoi in low Hg-contaminated soils, and Chicory in highly Hg-contaminated soils. Therefore, Hg concentration is mostly accumulated in roots of leafy crops, which reduces the risk of Hg bioaccumulation in edible portion of vegetables, and (2) Brassicaceae vegetables are mostly less sensitive to soil Hg contamination. Our results provide effective guidance for the selection of leafy vegetables for cultivation and daily consumption that minimizes health risk.
Afficher plus [+] Moins [-]Investigation of particulate matter by FTIR, TEM and elemental analyses in a diesel engine operating on diesel and waste cooking oil-biodiesel Texte intégral
2020
Ulusoy, Yahya
This study investigated the use of a blend of waste vegetable oil and diesel fuel in a diesel tractor engine by comparing the resulting particulate matter (PM) collected on a filter with the PM of diesel fuel. To this purpose, Fourier transform infrared (FTIR) and elemental analyses were carried out and the PM collected on the filters was examined via scanning electron microscopy (SEM). The study also investigated the overall morphology of soot particles from the blend of 75% waste cooking oil (WCO) + 25% diesel (B75) in a diesel engine at three different loads (75%, 50% and 10%) compared with the morphology of the soot particles from diesel fuel (B0). The FTIR spectra of the B75 fuel exhibited the characteristic regions of oxygen bonds. Compared to the B0 fuel, the increased oxidation from the excess oxygen in the B75 fuel reduced the size and number of soot particles. It was also verified that the degree of unsaturation was related to the oxygen content of the B75 fuel. The FTIR spectra of the B75 fuel showed a C = O tensile band methyl ester in 1734 cm⁻¹ and C–O bands at 1214–1362 cm⁻¹. Furthermore, similar FTIR spectra were seen for the diesel fuel (B0) and the B75 fuel. The results showed a significant reduction in soot particle emissions with the WCO-diesel blend. The results of this research have enabled a better evaluation of the effects of different fuel usage on diesel engine combustion performance and emission characteristics.
Afficher plus [+] Moins [-]Rosa persica hydroalcoholic extract improves cadmium-hepatotoxicity by modulating oxidative damage and tumor necrosis factor-alpha status Texte intégral
2020
Moradkhani, Shirin | Rezaei-Dehghanzadeh, Tayebeh | Nili-Ahmadabadi, Amir
Rosa persica is a member of the Rosaceae family that has a wide range of pharmacological properties. In this study, the antioxidant and therapeutic potential of this plant was investigated on cadmium (Cd)-induced hepatotoxicity. Rosa persica extract (RPE) was prepared by a maceration method in hydroalcoholic solvent, and its antioxidant properties were determined. Then, 36 mice were divided to six groups and treated for 2 weeks as follows: control, Cd (3 mg/kg), RPE (50 mg/kg), and groups 4–6 received Cd (3 mg/kg) and 12.5, 25, and 50 mg/kg of RPE respectively. The total polyphenol, flavonoids contents, and total antioxidant capacity in RPE were measured 263.4 ± 7.2 mg rutin equivalent/g extract, 72.3 ± 2.3 mg quercetin equivalent/g extract, and 8.46 ± 0.27 μmol ferrous sulfate/g extract, respectively. The in vivo results showed that Cd elicited remarkable hepatic injury that was manifested by the significant increase in serum hepatic enzymes. In addition, Cd significantly increased the levels of lipid peroxidation (LPO) and tumor necrosis factor-alpha (TNF-α) and decreased total thiol molecules (TTM) and total antioxidant capacity (TAC) in hepatic tissue. However, RPE decreased serum hepatic enzyme levels and improved oxidative hepatic damage by lowering the LPO and TNF-α levels and raising TAC and TTM in in Cd-treated groups. Although the RPE increased the metallothionein (MT) protein content, there was no change in MT gene expression. The present study showed that the RPE due to having antioxidant properties might partially prevent hepatic oxidative damage by the improvement of oxidant/antioxidant balance in animals exposed to Cd.
Afficher plus [+] Moins [-]Behavioural and biochemical alterations by chlorpyrifos in aquatic insects: an emerging environmental concern for pristine Alpine habitats Texte intégral
2020
Di Nica, Valeria | González, Ana Belén Muñiz | Lencioni, Valeria | Villa, Sara
This study aimed to assess how different concentrations of the insecticide chlorpyrifos (1.1, 5.24, 11, 52.4, 110, 262, 524 and 1100 ng L⁻¹) affect the swimming behaviour of Diamesa zernyi larvae following exposure. A video tracking system was employed to analyse two swimming traits (total distance moved and average speed) of the larvae simultaneously after 3 days of exposure to the pesticide at 2 °C. The behavioural results were also interpreted according to biochemical responses to oxidative stress (OS) induced by chlorpyrifos, based on malondialdehyde (MDA) and protein carbonyl (PCC) content. Both distance and speed significantly decreased after 72 h of exposure to chlorpyrifos concentrations of ≥ 110 ng L⁻¹, under which significant OS was detected as lipid peroxidation (level of MDA) and protein carbonylation (level of carbonyl). Analysis of altered swimming behaviour, along with MDA and carbonyl content, indicated that ≥ 110 ng L⁻¹ contamination levels of the insecticide cause the organism to reallocate energy normally used for locomotor activity to repair cell damage, which might explain the strong impairment to locomotor performance. Locomotor performance is an ecologically relevant trait for elucidating the population dynamics of key species, with disturbance to this trait having long-term negative impacts on population and community structure. Therefore, chlorpyrifos insecticides represent a serious ecological risk for mountain aquatic species based on the detrimental effects observed in the current study, as the tested concentrations were those at which the insecticide is found in many Alpine rivers of Italy.
Afficher plus [+] Moins [-]Determination of polychlorinated biphenyls in honeybee, pollen, and honey samples from urban and semi-urban areas in Turkey Texte intégral
2020
Sari, Mehmet Ferhat | Gurkan Ayyildiz, Emine | Esen, Fatma
In recent years, honeybees and bee products such as pollen and honey have been used as bioindicators for monitoring environmental pollution. Unfortunately, there are few studies about polychlorinated biphenyl (PCB) concentrations in honeybees and bee products from Turkey. Honeybee and pollen samples were taken between May and September 2017, and honey samples were taken between July and September 2017 at urban and semi-urban areas in Bursa (Turkey). PCB concentrations measured by gas chromatography-microelectron capture detector (GC-μECD) were found to be 135.46 ± 6.53, 81.47 ± 23.52, and 106.35 ± 21.60 ng g⁻¹ dry weight (dw) for honeybee, pollen, and honey samples in the urban area, respectively; and 126.35 ± 26.54, 67.57 ± 27.34, and 118.88 ± 55.28 ng g⁻¹ dw for honeybee, pollen, and honey samples in the semi-urban area, respectively. Pearson correlation was made between meteorological parameters and pollutant concentrations. According to the correlation results, a significant relationship was found between the pollen and honey results and the total cloudiness and temperature in the semi-urban area. The coefficient of divergence (COD) and Pearson correlation coefficient (PCC) methods were applied to determine the similarities and differences between the pollutant concentrations and sources of the two areas and the temporal variation. According to these two methods, PCB concentrations and emission sources in honeybee and pollen samples in urban and semi-urban areas were generally different in May and June, and similar in August and September.
Afficher plus [+] Moins [-]Research on energy efficiency improvement in a supply chain with discontinuous market demand Texte intégral
2020
Zu, Yafei | Zeng, Xiangfei
In many countries, products are divided into several grades according to their energy efficiencies by the government. It leads to the discontinuous market demand for the products with different governmental energy efficiency certifications and further influences the relevant strategies of firms. Considering both increasing consumer environmental awareness and strict governmental grading standard, this paper develops a Stackelberg differential game between a manufacturer and a retailer. The optimal pricing strategies and the energy efficiency efforts are studied, and the influences of discontinuous market demand on those optimal strategies are discussed. The results show that the governmental grading standard has an important boosting impact on the energy efficiency level of products. When the product’s energy efficiency level is lower than the governmental standard, the manufacturer will make great efforts on energy efficiency improvement. It would be beneficial for both the manufacturer and the retailer to use penetration pricing strategy during this period. Once the governmental standard is met, the manufacturer will reduce his effort significantly. At this time, taking the skimming pricing strategy is beneficial for both the manufacturer and the retailer. Moreover, a higher governmental standard and a larger consumers’ preference difference can motivate the manufacturer to work harder to improve energy efficiency. They also lead to a higher price after the product is certified as the high energy efficiency product by the government.
Afficher plus [+] Moins [-]The willingness and perception of people regarding green roofs installation Texte intégral
2020
Sarwar, Suleman | Alsaggaf, Majid Ibrahim
Developing economies are facing multifaceted problems like dramatic increase in motorized traffic, urban heat island, urban sprawl, and climatic changes. Environmental Performance Index report states that Pakistan is on 169 among 180 countries due to ill-planned development on prime agriculture land, poor air, water quality, and jeopardizing ecosystem of the country. The change of land uses from the natural to the built environment has created problems like loss of vegetation and habitat, enlarged surface flow, and heavy floods. However, this study addresses this core issue by taking responses from the residents of Lahore, Pakistan. Current research focuses on the willingness and perception of residents regarding the adaptation of green roof technology. The resident perceptions are obtained by a structured questionnaire and analyzed by using statistical techniques. The findings of the research highlight that adaptation of green roof is primarily linked with the four factors, i.e., awareness of green roof among all stakeholders, special provision in building regulation concerning green roof, sustainable environmental consciousness, and subsidized cost of green roof materials.
Afficher plus [+] Moins [-]Pelagic Sargassum spp. capture CO2 and produce calcite Texte intégral
2020
Paraguay-Delgado, Francisco | Carreño-Gallardo, Caleb | Estrada-Guel, Ivanovich | Zabala-Arceo, Alberto | Martinez-Rodriguez, Harby Alexander | Lardizábal-Gutierrez, Daniel
Pelagic Sargassum is considered an ecological plague that is causing adverse economic impacts to the tourist and fishing industries in the Caribbean. However, its proliferation might be playing an important role to reduce global warming, as it removes a high content of CO₂ from the atmosphere and transforms it into calcium carbonate, in its calcite phase, producing sediment after it dies. We quantified the amount of calcite in Sargassum samples collected from the Mexican Caribbean coast in 2019. Samples were divided into three parts: vesicles, thallus, and leaves. In each part, the amount of carbon, oxygen, and calcium was determined by means of X-ray energy dispersion to confirm the existence of a calcite crystalline phase. Imaging methodologies and IR spectroscopy complemented the structural studies. The thermogravimetric analysis determined that approximately 5% of the CO₂ captured by the Sargassum was converted into calcite. Thus, by extrapolation, the Atlantic Sargasso Belt retained approximately 19.3 million tons of CO₂ from 2011 to 2019.
Afficher plus [+] Moins [-]Crayfish shell biochar modified with magnesium chloride and its effect on lead removal in aqueous solution Texte intégral
2020
Zhang, Jiaqi | Hudielan, | Yan, Jinpeng | Long, Li | Xue, Yingwen
In this study, crayfish shell was pyrolyzed at 600 °C to obtain an unmodified biochar (CS600). MgCl₂ was used as a modifier to pretreat crayfish shell to produce a modified biochar (CS600-MgCl₂) under the same pyrolysis conditions. The two biochars were characterized for physicochemical properties and evaluated for lead (Pb²⁺) sorption ability to determine the modification mechanism. Mono-element batch adsorption experiments were conducted to compare the sorption performances of CS600 and CS600-MgCl₂ to Pb²⁺ in aqueous solutions. All the experiments were carried out at pH of 7. According to the Freundlich–Langmuir model, CS600-MgCl₂ had a higher adsorption capacity (152.3 mg/g) than CS600 (134.3 mg/g). FTIR, SEM, XRD, BET, and ICP analyses were applied to inform the interpretation of the mechanism. CS600 was calcium-rich and mainly removed Pb²⁺ through the ion exchange mechanism by replacing Ca²⁺ in the biochar. The increased Pb²⁺ adsorption capacity of CS600-MgCl₂ was mainly due to the enlarged specific surface area and the formation of Mg₃(OH)₅Cl·4H₂O on the modified biochar. Findings of this study suggest that both CS600 and CS600-MgCl₂ can be used to remove heavy metal ions from wastewater and MgCl₂ can improve the sorption performance of biochar.
Afficher plus [+] Moins [-]