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Impacts of different freeze-thaw treatments on the adsorption and desorption behaviors of Cd in black soil Full text
2020
Wang, Quanying | Sun, Jingyue | Yu, Hongwen
Seasonal freeze-thaw cycle (FTC) is one of the key processes that affect heavy metal behaviors in soil. However, previous studies are mainly focused on extreme FTC treatments which may exaggerate the real FTC effects in the field. This study aimed to compare the effects of different FTC conditions on the adsorption and desorption behaviors of Cd in the surface black soil. Different minimum freezing temperatures (− 2, − 5, and − 15 °C), FTC rates (1 and 20 °C h⁻¹), freezing lengths (2 and 24 h), and FTC frequencies (1, 3, and 9) were investigated. The thawing temperature was set at 5 °C. The amplitude for the FTC rate, length, and frequency experiments ranged from 5 to − 2 °C. Our results indicated that the adsorption amounts of Cd presented an order of − 2 °C > − 15 °C > − 5 °C and 24 h > 2 h for different FTC amplitude- and freezing length-treated soils, and the adsorption amounts decreased with increasing FTC rate and frequency. Soil maximum adsorption amount of Cd increased with the increases of FTC frequency, freezing length, and FTC rate, while it decreased with the decreases of freezing temperature. Soil Cd desorption ratio decreased with the increases of FTC frequency, freezing length, and TFC rate, and it increased with the increasing freezing temperature. Our results suggested that FTC conditions can significantly influence the adsorption and desorption behaviors of heavy metal in soil.
Show more [+] Less [-]Ecological implication of offshored economic activities in Turkey: foreign direct investment perspective Full text
2020
Udemba, Edmund Ntom
Turkish place in industrial activities is strategic, and its involvement in oil and gas importation because of high energy utilization in manufacturing sector is susceptible to high emission. For this, it is required that the economy be researched towards its involvement in both emission inducement and abatement globally. The author adopts ecological footprint and offshored economic activities as proxies to both environment and foreign direct investment (FDI) in ascertainment of Turkish involvement in global emission and decarbonization. Structural break analysis, autoregressive distributed lag–bound testing, and Granger causality were utilized for the effective analysis of the offshore implication of environmental performance in Turkey. The author’s findings are as follows: a positive relationship between economic performance (GDP per capita) and ecological footprint, hence giving credence to growth-induced pollution. Also, a positive relationship is established among foreign offshored economic activities (FDI), energy use, and ecological footprint which shows that both energy use and foreign offshored economic activities are positively related to the ecology which established unfavorable impact on the environment. This supports the pollution haven hypothesis (PHH) which is among the theoretical backgrounds of this study. Among the findings established in this study is from Granger causality method which supports the pollution haven hypothesis. They are as follows: a feedback causal transmission between FDI and the ecological footprint, and a one-way causal relationship passing from energy use to ecological footprint. With these findings, it can be said that the environmental implication of foreign offshored economic activities in Turkey is unfavorable. Policy implication of Turkey should be towards moderation of economic growth and the activities of foreign investors for sustainable energy, environment, and growth. Graphical abstract A display of the author’s findings which are as follows: a positive relationship between economic performance (GDP per capita) and ecological footprint. Also, a positive relationship is established among foreign offshored economic activities (FDI), energy use, and ecological footprint which shows that both energy use and foreign offshored economic activities are positively related to the ecology (this relationship is shown on the graph with red colored arrows moving from independent variables to the dependent variable). From Granger causality method, the author found a feedback causal transmission between FDI and the ecological footprint, and a one-way causal relationship passing from energy use to ecological footprint (this relationship is shown with blue arrows showing either two-way transmission for the case of FDI and ecology or one-way transmission for the case of energy use to ecology).
Show more [+] Less [-]Biochemical, hematological and immunological parameters and relationship with occupational exposure to pesticides and metals Full text
2020
Cestonaro, Larissa V. | Garcia, Solange Cristina | Nascimento, Sabrina | Gauer, Bruna | Sauer, Elisa | Göethel, Gabriela | Peruzzi, Caroline | Nardi, Jessica | Fão, Nuryan | Piton, Yasmin | Braga, Wesley | Rocha, Rafael | Saint’Pierre, Tatiana | Gioda, Adriana | Arbo, Marcelo Dutra
This study aimed to evaluate biomarkers of exposure to cholinesterase inhibitors insecticides (AChE and BuChE activities) and metals (As, Cd, Cr, Mn, Ni, and Pb blood levels) and their associations with biochemical, hematological, and immunological parameters in farmers from Southern Brazil. One hundred and sixteen individuals were divided into two groups: 62 farmers (exposed group) and 54 subjects non-occupationally exposed (NOE) to agrochemicals. Erythrocyte (AChE) and serum (BuChE) cholinesterases activities were significantly reduced as well as blood Cd and Pb levels were increased in farmers when compared to NOE group (p < 0.05). Farmers presented increased glucose and urea levels compared to NOE group, which were inversely associated with AChE and positively correlated with Cd (p < 0.05), respectively. In addition, Cd was inversely associated with the hematological cells counts, which were significantly reduced in farmers (p < 0.05). C3 complement was higher in farmers and was positively associated with blood Pb (p < 0.05). Surface protein expression analysis revealed a downregulation of LFA-1 and ICAM-1 in farmers. Inverse associations were found between LFA-1 and blood As, Cr, and Ni levels (p < 0.05). Taken together, our results pointed to a relationship between agrochemicals and metals exposure and biochemical, hematological, and immunological disorders that can lead to several chronic conditions.
Show more [+] Less [-]Factors affecting the removal of bromate and bromide in water by nanofiltration Full text
2020
Lin, Dachao | Liang, Heng | Li, Guibai
Bromide is universal in surface water influenced by salt tide and brackish water. It is harmless to human until transferring to bromate (a kind of disinfection byproducts) under certain conditions such as oxidation. Though both of them are not easily removed by conventional water treatment, nanofiltration seems to be an efficient way to solve the problems. In this study, the removal of bromate and bromide by nanofiltration membranes were systematically investigated, considering the system pressure (0.2–0.3–0.4 MPa), pH (5–7–9), ionic strength (0.005–0.05–0.1 mM), membrane type (NF270 and NF90), and the influences of organic matters (humic acid and sodium alginate). The membrane flux and the removal efficiency of anions were taken into consideration. According to the results, the membrane flux increased along with the system pressure, but slight influence on the removal of bromate and bromide was observed. Rising pH and ionic strength could not obviously deteriorate the flux. However, the removal of these anions was enhanced by increasing pH as well as decreasing ionic strength. Compared with humic acid, severer flux decline and deterioration of anion removal were achieved when sodium alginate was added in feed solution. Regardless of the operating conditions, bromate was more easily removed by nanofiltration membranes than bromide, which could result from different steric hindrance. Compared with NF270, NF90 can reject bromide and bromate more efficiently. The findings in the present study would contribute to the deep understanding of the factors affecting removal of bromate and bromide by nanofiltration and provides guidance about application of it.
Show more [+] Less [-]Preparation and uranium (VI) biosorption for tri-amidoxime modified marine fungus material Full text
2020
Han, Jingwen | Hu, Lin | He, Leqing | Ji, Kang | Liu, Yaqing | Chen, Can | Luo, Xiaomei | Tan, Ni
The preparation, characterization, and uranium (VI) adsorption properties of tri-amidoxime modified marine fungus material (ZZF51-GPTS-EDA-AM/ZGEA) were investigated in this study. ZGEA was synthesized by four steps of condensation, nucleophilic substitution, electrophilic addition, and nitrile amidoxime and characterized by a series of methods containing FT-IR, TGA, SEM, and BET. Contrasted with uranium (VI) adsorption capacity of original fungus mycelium (15.46 mg g⁻¹) that of the functional material (584.60 mg g⁻¹) was great under the optimal factors such as uranium (VI) ion concentration 40 mg L⁻¹, solid-liquid ratio 50 mg L⁻¹, pH of solution 5.5, and reaction time 120 min. The above data were obtained by the orthogonal method. The cyclic tests showed that ZGEA had good regeneration performance, and it could be recycled at least five adsorption-desorption processes. The thermodynamic experimental adsorption result fitted Langmuir and Freundlich models, which explored monolayer and double layers of uranium (VI) adsorption mechanism, and the kinetic adsorption results were in better consistent with the pseudo-second-order and pseudo-first-order dynamic models (R² > 0.999).
Show more [+] Less [-]CYP1A1 and GSTs common gene variations and presbycusis risk: a genetic association analysis and a bioinformatics approach Full text
2020
Karimian, Mohammad | Behjati, Mohaddeseh | Barati, Erfaneh | Ehteram, Tayyebeh | Karīmiyān, ʻAlī
Antioxidant enzymes such as glutathione S-transferases (GSTs) and cytochromes P450 (CYPs) are involved in the metabolism and detoxification of cytotoxic compounds, as well as the elimination of reactive oxygen species (ROS). Therefore, alterations in the structure of these enzymes could result in prolonged production of ROS with subsequent risk of development of disorders such as presbycusis. This study aimed to investigate the association between CYP1A1 (rs4646903, rs1048943) and GSTs (GSTM1-deletion, GSTT1-deletion, GSTP1-rs1695) with presbycusis risk in an Iranian population which was followed by an in silico approach. In a case-control study, 280 subjects including 140 cases with presbycusis and 140 healthy controls were enrolled. Genotypes of single-nucleotide polymorphisms (SNPs) were detected by PCR-RFLP method and the genotype of the above mentioned deletions was determined by touchdown PCR. Some bioinformatics tools were employed to evaluate the impact of SNPs on the gene function. SNP analysis revealed that there are significant associations between rs1048943 (AG vs. AA: OR = 2.46, 95%CI = 1.30–4.65, p = 0.006; GG + AG vs. AA: OR = 2.53, 95%CI = 1.36–4.69, p = 0.003; G vs. A: OR = 2.36, 95%CI = 1.33–4.17, p = 0.003) and rs4646903 (C vs. T: OR = 1.45, 95%CI = 1.02–2.06, p = 0.040) variations and increased risk of presbycusis. However, there was no significant association between rs1695 and presbycusis risk. Also, significant associations were observed between GSTM1 (OR = 4.28, 95%CI = 1.18–15.52, p = 0.027) and GSTT1 (OR = 1.64, 95%CI = 1.02–2.65, p = 0.041) deletions and elevated risk of presbycusis. Moreover, the combination analysis revealed a significant association between GSTM1+/GSTT1− genotype and presbycusis susceptibility (OR = 1.63, 95%CI = 1.00–2.67, p = 0.049). In silico analysis revealed that the rs1048943 SNP could influence significantly on the RNA structure of CYP1A1 (distance: 0.1454; p value: 0.1799). Based on our findings, the rs4646903, rs1048943 SNPs as well as GSTM1 and GSTT1 deletions could be considered as genetic risk factors for the development and progression of presbycusis.
Show more [+] Less [-]Geochemical features and potential environmental implications of heavy metals in mining-impacted sediments, south China Full text
2020
Yan, Bo | Xu, Da-Mao | Chen, Tao | Yan, ZiAng | Li, Lili
The present study was initiated to investigate the geochemical features and associated pollution risks of selected heavy metals in sediments near an active copper sulfide mines, south China. These results indicated that legacy contamination in sediments were mainly Cd (11.9 mg/kg), Cu (0.106%), Pb (0.189%), Zn (0.0958%), and As (0.158%). Furthermore, the geochemical variability of most elements, ranging from 5.66% for K₂O to 24.99% for Cd, was relatively lower. On the spatial scale, the variation patterns of multi-elements did not show a decreasing trend. The multivariate statistical analysis revealed that the significant enrichment of the studied elements was mostly related to the geochemical background and anthropogenic sources. Besides that, the stable climate might have positive influences on the leachability patterns of heavy metals in sediment profiles. According to the results of the potential ecological risk index (PERI), Cd, Cu, Pb, and As were identified as the riskiest elements due to their rather higher contribution ratios to pollution risk. In response to continuous exposure risks, the significant enrichment of these mining-derived elements should be preferentially concerned. Finally, some reasonable action is proposed for aquatic environment protection. Graphical abstract
Show more [+] Less [-]Cost analysis of environmental protection price of coal-fired plants in China Full text
2020
Zhao, Yi | Zhang, Jingjie | Wang, Zhixuan
In the paper, the achievements obtained from carrying out the policy of environmental protection price for promoting air pollution control in coal-fired power plants in China during more than a decade were summarized. Based on the situation of current electricity market reform, the role and effectiveness of environmental protection price for controlling the normal air pollutants, such as sulfur dioxide, nitrogen oxides, and dust in China’s coal-fired power generation plants, were investigated, including the price structure of electricity environmental protection for coal-fired power generation enterprises in different regions, generating units, and power demands. The policy suggestions were proposed, namely, the reform of electricity environmental protection price would be carried out gradually, the relationship between electricity environmental protection price policy and other environmental protection policies would be matched under the relative overcapacity condition, and the environmental protection price regulation would be integrated into other environmental policies.
Show more [+] Less [-]Ambient air pollution and its influence on human health and welfare: an overview Full text
2020
Almetwally, Alsaid Ahmed | Bin-Jumah, May | Allam, Ahmed A.
Human health is closely related to his environment. The influence of exposure to air pollutants on human health and well-being has been an interesting subject and gained much volume of research over the last 50 years. In general, polluted air is considered one of the major factors leading to many diseases such as cardiovascular and respiratory disease and lung cancer for the people. Besides, air pollution adversely affects the animals and deteriorates the plant environment. The overarching objective of this review is to explore the previous researches regarding the causes and sources of air pollution, how to control it and its detrimental effects on human health. The definition of air pollution and its sources were introduced extensively. Major air pollutants and their noxious effects were detailed. Detrimental impacts of air pollution on human health and well-being were also presented.
Show more [+] Less [-]A systematic study of the synthesis conditions of blue and green ultramarine pigments via the reclamation of the industrial zeolite wastes and agricultural rice husks Full text
2020
Wang, Haibo | Zhang, Shan | Hu, Songyuan | Zhen, Zhiwei | Gomez, Mario Alberto | Yao, Shuhua
Discarded industrial zeolite waste and agricultural rice husks have caused a waste of resources. To achieve resource reuse, we proposed an economical method for the preparation of ultramarine pigments via the reclamation of industrial zeolite waste (ZW) and agricultural rice husks (RHs) or previously bio-charred rice husks (BRHs). The optimal blue and green pigments were synthesized by solid state reaction of mixtures of BRH/ZW/Na₂CO₃/S with mass ratios of 1:2:1:1.5 and 2:2:7:3, respectively, and using a two-step calcination process with a first stage at 500 and a second stage at 800 °C. Furthermore, the blue and green pigments were also obtained using directly RH (instead of BRH) as raw material, but this time with RH/ZW/Na₂CO₃/S mass ratios of 1:2:2:3 and 1:2:7:3.5 and with first-stage and second-stage calcination temperatures of 400 and 800 °C. This was done to reduce additional chemical reactions (e.g., BRH derived from the pyrolysis of RH). The XRD, FT-IR, Raman, and SEM results suggest that the synthetic blue and green pigments have the sodalite structure containing S₃⁻ and S₂⁻ radicals. The synthetic green pigment using RH as raw material had the best acid resistance. Additionally, the synthesis of blue and green ultramarine pigments via the reclamation of the industrial zeolite wastes and agricultural rice husks can reduce the costs of the production process.
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