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Experimental and material characterization of composites, including waste iron and marble powder Texte intégral
2022
Gülmez, Nihan
Due to its fine particle size, waste marble slurry originating in cutting and processing units mixes into the air after drying, causing environmental and health problems in nearby areas. On the other hand, large amounts of iron particles are generated as metalworking industry waste, affecting the environmental system. In this study, 0%, 10%, and 20% marble powder (instead of cement) and iron particles (instead of fine aggregate) were used in mixtures, and the composites produced were subjected to two different curing periods: 7 and 28 days. The physical, mechanical, microstructural, and thermal properties of the fresh and hardened composites were ascertained via bulk density, consistency, porosity, water absorption, capillary water absorption, strength tests, particle size distribution, X-ray diffraction (XRF), X-ray fluorescence (XRF), scanning electron microscopy and energy dispersive spectroscopy (SEM–EDS), and thermogravimetric analyses (TGA). The results revealed that minimum water absorption (8.5%) and porosity (19.8%) values were achieved in 28-day composites produced with 10% marble–20% iron wastes among all composites. Thus, iron particles substituted for natural aggregates were mainly responsible for the increase in mechanical performance. A maximum flexural strength of 5.9 MPa and a compressive strength of 26.7 MPa were observed in 28-day composites containing 0% marble–20% iron wastes. Furthermore, capillary water absorption tended to decrease with the substitution of 10% marble powder.
Afficher plus [+] Moins [-]Spatiotemporal variation and driving forces of NDVI from 1982 to 2015 in the Qinba Mountains, China Texte intégral
2022
Zhang, Yaru | He, Yi | Li, Yanlin | Jia, Liping
The spatiotemporal variation and driving force of the Normalized Difference Vegetation Index (NDVI) are helpful to ecological environment protection and natural resource management. Using the Sen and Mann–Kendall methods, Hurt index, and the Geodetector, this study investigated the temporal and spatial changes and driving forces of NDVI during 1982–2015. The results showed that (1) From 1982 to 2015, the high vegetation coverage was mainly distributed in the Qinling Mountains and the Daba Mountains, while the low vegetation coverage was in high altitude areas in the west, low altitude in the east, and the Hanjiang River valley. (2) NDVI in the Qinba Mountains increased continuously accounting for 81.1%, with 68% showing slow growth. In the future, only 37.8% of the vegetation will have significant change. The area of vegetation increase will be greater than the area of decrease. (3) NDVI increased firstly and then decreased with the increase of altitude, reaching the maximum value at 1100 m. NDVI showed a trend of fluctuating growth. It reached the maximum value of 0.86 in 2015. (4) Through the Geodetector, the main factors affecting NDVI were natural factors mainly including rainfall, soil type, and digital elevation model (DEM), while human activities, including population density, had little influence on NDVI. Natural environment factors and human activities together had a greater impact on the spatial distribution of NDVI. This study could provide help for the sustainable development of the natural environment in the Qinba Mountains.
Afficher plus [+] Moins [-]Association between high-risk pregnancy and environmental contaminants in the Metropolitan Region of Baixada Santista, Brazil Texte intégral
2022
Fernandes, Joice Maria Pacheco Antonio | de Aguiar Pontes Pamplona, Ysabely | Vaz, Jhonnes Alberto | Pereira, Amanda Rodrigues | Barbieri, Carolina Luísa Alves | Braga, Alfésio Luís Ferreira | Martins, Lourdes Conceição
The Metropolitan Region of Baixada Santista (MRBS) is a highly contaminated area. High-risk pregnancy is one factor that leads to a higher chance of both morbidity and mortality of the mother-fetus binomial. The purpose of this study is to analyze the association between exposure to environmental contaminants and high-risk pregnancy. Case–control study, using a probabilistic and random sample composed of 201 high-risk pregnant women (cases) and 201 no high-risk pregnant women (control) followed up during prenatal care at a Public Hospital. The instrument used was a self-administered questionnaire. Contaminated areas data were obtained from the Environmental Company of the São Paulo State. The participants were georeferenced by their place of residence. Descriptive analysis, Chi-square test, and univariate and multiple logistic regression analysis were performed. The multiple logistic regression model demonstrated that living in a contaminated area (OR = 1.565; 95%CI: 1.033; 2.370), preterm delivery in the current pregnancy (OR = 1.989; 95%CI: 1.239; 3.194), and more than 35 years old (OR = 2.822; 95%CI: 1.692; 4.706) are factors jointly related to high-risk pregnancy. Environmental contaminants play an important role in high-risk pregnancy, and mitigating measures are needed to improve the environment and reduce high-risk pregnancy.
Afficher plus [+] Moins [-]Zincum Metallicum, a homeopathic drug, alleviates Zn-induced toxic effects and promotes plant growth and antioxidant capacity in Lepidium sativum L Texte intégral
2022
Boudali, Ghazwa | Ghnaya, Tahar | Ben-Abdallah, Saoussen | Chalh, Abdallah | Sebei, Abdelaziz | Ouirghi, Zeineb | Chaffei-Haouari, Chiraz
In this study, we investigated the effect of the homeopathic drug Zincum Metallicum (ZM) on zinc (Zn) toxicity in the plant species Lepidium sativum L. We focused on growth parameters, Zn uptake and numerous biochemical parameters. Seedlings were hydroponically subjected during 7 days to 0.05, 500, 1000, 1500 and 2000 µM Zn²⁺, in the absence or presence of 15ch or 9ch ZM. In the absence of ZM, Zn induced negative effect on growth especially at the dose of 2 mM. Zn induced also chlorosis, reduced total chlorophyll and/or carotenoid content and increased the level of malondialdehyde (MDA). Under Zn toxicity (500, 1000 and 1500 µM), the superoxide dismutase (SOD), catalase (CAT), gaiacol peroxidase (GPX) and glutathione reductase (GR) activities were increased or not significantly affected, while at 2000 µM Zn affected the activity of these enzymes. At the highest Zn level (2 mM), proline and total polyphenol and flavonoid contents were markedly increased in leaves and roots of L. sativum. Additionally, ZM supply considerably ameliorated the plant growth, photosynthetic pigment contents and increased non-enzymatic antioxidant molecules and enzymatic activities against Zn-induced oxidative stress. Our data suggest that homeopathic properties of ZM may be efficiently involved in the restriction of Zn-induced oxidative damages, by lowering Zn accumulation and translocation in the leaves and roots of Lepidium sativum L.
Afficher plus [+] Moins [-]A review on low-temperature thermal desalination approach Texte intégral
2022
Natarajan, Sendhil Kumar | Suraparaju, Subbarama Kousik | Elavarasan, Rajvikram Madurai
The scarcity of clean and safe water is one of the most perilous glitches faced by the world. The pure drinking water resources across the world are depleting progressively due to rapid industrialization and growth in population. The conceivable solution for this problem is converting the available seawater into pure drinking water through several techniques of desalination. In the stream of desalination, many prodigious endeavours are in evolution to increase the reliability of the process by cutting down the principal and maintenance costs. Among several desalination approaches, low-temperature thermal desalination (LTTD) is an intriguing and advancing trend in the desalination process by using low temperatures and pressures in a range similar to ambient temperatures and vacuum pressures. The LTTD technique is operated by taking the energy input from waste heat, thermoclines and renewable energy sources. However, the operating temperatures of the LTTD system are less than 50 °C. The development of this particular LTTD process driven by renewable energy sources has gone through various stages, based on the water–energy demands, environmental concerns and technological progressions. In this article, the historical developments of the LTTD process using several renewable and non-renewable energy sources have been reviewed. Finally, some future recommendations for further developments in this approach are discussed. This article paves the path for the researchers working in desalination to choose an appropriate LTTD approach that is more viable and sustainable than the conventional desalination systems.
Afficher plus [+] Moins [-]Ecotoxicity of polyelectrolyte formulations in water and soil matrices Texte intégral
2022
Yakimenko, Olga | Ziganshina, Aliya | Terekhova, Vera | Panova, Irina | Gladkova, Marina | Timofeev, Mikhail | Yaroslavov, Alexander
Interpolyelectrolyte complexes (IPECs) formed by the interaction of two oppositely charged polyelectrolytes have been proposed as soil structure stabilizers. However, little is known about the environmental safety of IPECs. The goal of this study was to investigate the toxicity of a positively charged IPEC formed by two commercial polymers, namely the cationic biopolymer poly(diallyldimethylammonium chloride) (PDDA) and the anionic biopolymer lignohumate (LH), a humic-based plant growth promoter. Toxicity was assessed using cultures of the bacteria Escherichia coli, the ciliate Paramecium caudatum, mammalian (Bos taurus) spermatozoa in vitro, and three plant species (Sinapis alba, Raphanus sativus, and Triticum durum). The responses of test organisms were evaluated in contact with (1) polymer and water and (2) polymer and soil. In water, PDDA and IPEC were highly toxic to bacteria and ciliates at all concentrations and less toxic to mammalian cells. Higher plants were less sensitive to the polymers, and the toxicity progressively decreased in the order PDDA > IPEC > LH. In soil matrices; the phytotoxicity of PDDA and IPEC was found to be quite low, and none of the polymers was toxic to plants at concentrations that allowed the formation of polymeric soil crusts against erosion. This is because the toxicity of cationic polymers decreases as they enter the soil matrix and bind to organic matter and minerals.
Afficher plus [+] Moins [-]Non-targeted analysis with high-resolution mass spectrometry for investigation of riverbank filtration processes Texte intégral
2022
Kutlucinar, Kaan Georg | Handl, Sebastian | Allabashi, Roza | Causon, Tim | Troyer, Christina | Mayr, Ernest | Perfler, Reinhard | Hann, Stephan
A fully non-targeted analytical workflow for the investigation of a riverbank filtration site located at the river Danube has been developed and applied. Variations of compound intensities at different sampling locations of the riverbank filtration site and, for a single production well, over a monitoring period of one year have been investigated using liquid chromatography combined with time-of-flight-mass spectrometry followed by evaluation via non-targeted data analysis. Internal standardization and appropriate quality control strategies have been implemented into the workflow for reduction of possible methodological biases influencing data interpretation. Emphasis was placed on the assessment of different blank elimination steps and the final blank elimination strategy is reported. The spatial study of the selected riverbank filtration site revealed a homogenous composition of the filtered water sampled at 11 different locations across the 32,000 m² site, except for one sampling location in a zone of the aquifer, which was only weakly connected to the well field in terms of hydrogeological conditions. The examination of time-dependent changes of the composition of surface and groundwater obtained at the riverbank filtration system revealed that the non-targeted workflow is fit-for-purpose regarding the assessment the stability of filtration efficiency and compound residence time in the riverbank filtration compartment. In total, 677 compounds were selected for the investigation of the time-dependent variations of the filtration process. Analysis of the signal intensities of these compounds revealed that the riverbank filtration is significantly reducing the intensity and number of compounds present in surface water over a wide polarity range. In addition, the method enabled the determination of compound residence times in the riverbank filtration system ranging from 5 to 7 days.
Afficher plus [+] Moins [-]Evaluation of formaldehyde exposure among gross dissection after modified embalming solution and health assessment Texte intégral
2022
Soonklang, Nantawan | Saowakon, Naruwan
Mainly embalming fixative contains formaldehyde which is classified as a carcinogen. People who work with cadavers have been at higher risk of cancer after formaldehyde exposure. We have formulated a less-formalin fixative (contained 3.6% formaldehyde,23.8% ethanol, 15% glycerin, and 0.2% phenol in the water) for preserving cadavers. Therefore, the objective of the present study was to evaluate the level of atmospheric formaldehyde indoors and the breathing exposure of medical students during dissection classes. We also analyzed the pulmonary parameters and effects of formaldehyde. The levels of atmospheric formaldehyde indoors and personal breathing exposure were sampled during anatomy dissection classes (musculoskeletal system, respiratory system, and abdominopelvic organ system) using sorbent tubes with air sampling pumps. Samples were then analyzed using Gas Chromatography with Flame Ionization Detector (GC-FID). The mean level of formaldehyde indoor air among the three classes was 0.518 ± 0.156 ppm whereas the formaldehyde level in the personal breathing zone was 0.956±0.408 ppm, which exceeded the recommended exposure standards of international agencies, including NIOSH agency and PEL of Thailand legislation. The laboratory had high humidity, high room temperature, and poor air ventilation. There was a significant difference in FVC, FEV1, and PEF (p < 0.05) between the sexes of students. Comparison pulmonary parameters between students and instructors showed that all parameters of the pulmonary function test had no significant differences. General fatigue and burnings of eyes and nose associated with strong odor were the most common symptoms reported during the dissection classes. The modified embalming fixative was used less formalin with ethanol-glycerin mixture, and it was suitable for the study of medical students, with few side effects of respiratory problems. However, the modified exhaust ventilation with local table-exhaust ventilation and heating-ventilation-air conditioning system performance were urgent issues for reducing levels of formaldehyde indoor air in the dissection room.
Afficher plus [+] Moins [-]Modelling the globalization-CO2 emission nexus in Australia: evidence from quantile-on-quantile approach Texte intégral
2022
Adebayo, Tomiwa Sunday | Acheampong, Alex O.
Sustainable development policies for achieving net-zero emissions require understanding the factors that influence carbon emissions. Capitalizing on the limitations of the existing literature, this study applies the quantile-on-quantile approach to investigate economic globalization’s impact on carbon emissions in Australia for 1970–2018. The results from the quantile-on-quantile revealed a positive feedback linkage between globalization and carbon emissions at all quantiles. The results further indicated that while there is a positive feedback linkage between economic growth and carbon emissions at most quantiles, a positive feedback interconnection exists between carbon emissions and coal consumption at all quantiles. As a robustness check, we employed the quantile regression test, and the results from quantile regression are consistent with the findings from the quantile-on-quantile approach. The consistency of the results suggests that these study findings are reliable and suitable for informing policies that seek to address carbon emissions in Australia. The policy implications for Australia are discussed.
Afficher plus [+] Moins [-]Normal concentration range of blood mercury and bone mineral density: a cross-sectional study of National Health and Nutrition Examination Survey (NHANES) 2005–2010 Texte intégral
2022
Tang, Yuchen | Yi, Qiong | Wang, Shenghong | Xia, Yayi | Geng, Bin
High blood mercury levels could lead to mercury poisoning, undoubtedly causing great harm to human health. However, the impact of the normal concentration of blood mercury on bone mineral density (BMD) is unclear. Therefore, this study explored the relationship between blood mercury levels and BMD and determined whether the relationship between blood mercury and BMD differs by populations. Two researchers extracted data from the 2005–2010 National Health and Nutrition Examination Survey database. Multivariate linear regression models were performed to evaluate the relationship between mercury level and BMD of the femoral regions and spine. Subgroup analysis was used to estimate differences according to population subgroups. Moreover, the nonlinear relationship of blood mercury levels and BMD was assessed using smooth curve fitting and generalized additive models. The results showed increased BMD with increasing mercury levels by multivariable-adjusted linear regression models, especially in the femoral regions. Subgroup analysis showed that the relationship was more likely to be present in non-Hispanic Whites, while a negative correlation between blood mercury levels and spinal BMD was observed in non-Hispanic Blacks. Furthermore, males (aged 20 to 29 years) and females (aged 30 to 39 years) with low blood mercury levels (< 3 ug/L) had increased risks of osteopenia or osteoporosis. This study showed that blood mercury level within the normal reference value of 10 μg/dL may be associated with BMD, especially with a lower blood mercury level, which may suggest an elevated risk of osteopenia or osteoporosis. However, causation could not be established due to the study design.
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