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Evaluation of cytokines in exhaled breath condensate in an occupationally exposed population to pneumotoxic pollutants 全文
2022
Díaz de León Martínez, Lorena | Grimaldo-Galeana, José Moisés | Alcántara-Quintana, Luz Eugenia | Díaz-Barriga, Fernando | Pérez-Vázquez, Francisco Javier | Flores Ramírez, Rogelio
The quarrying is considered a precarious occupation with high toxicity, is an informal economic activity that employs low technology, limited protection, and poses a risk to workers and their families. In quarrying, silica dust is generated and there is also occupational exposure to significant mixtures of pneumotoxic pollutants, including mineral dust (crystalline silica, carbon or cement, polycyclic aromatic hydrocarbons (PAHs), solvents, and others, which are aggravated by the lack of use of protective equipment, causing irreversible damage to the worker’s respiratory health. Thus, the objective of this work focused on the evaluation of the respiratory health of artisan stonemasons in San Luis Potosí, Mexico through the study of exhaled breath condensate (EBC) (pH, pro-inflammatory cytokines) as well as the study of the exposure to pollutants present in the work area (PAHs, toluene, and 2.5 µm particulate matter) through biomarkers of exposure (hippuric acid and hydroxylated metabolites of PAHs). The results show the presence of crystalline SiO₂ in 100% of the samples analyzed; the PM₂.₅ concentrations were 5 to 10 times the permitted levels. Regarding exposure to PAHs, all the stonemasons presented urine concentrations of at least 5 of the OH-PAHs evaluated; 9-OH-FLU occurred at higher concentrations of 171.2 (122.7–279.4) µg L⁻¹; hippuric acid, which was present in 100% of the workers evaluated in concentrations of 283.4 (27.72–1119) mg L⁻¹, 100% of which were above the values established for occupational scenarios. The pH values obtained for the EBC samples were presented at an average of 7.07 (6.33–7.66). Pro-inflammatory cytokines were present in 86.1% of the study population. The cytokine that was found in higher concentrations was IL-2, with a mean of 178.01 pg mL⁻¹ and 3124.01 pg mL⁻¹ for the pH < 7 and pH > 7 groups, respectively. Some correlations between the cytokines and the exposure biomarkers were presented. Stonemasons are highly exposed to pneumotoxic pollutants and markers of inflammation at the pulmonary level; in addition, a high risk of developing silicosis. Quarrying should be addressed as a carcinogenic activity, which would imply the design of monitoring and control strategies for these pollutants that our country currently lacks, particularly in precarious occupations. It is necessary to develop strategies to protect the health of precarious workers.
显示更多 [+] 显示较少 [-]Improvement of water recovery from phosphate sludge at the M'Dhilla Mine, Tunisia 全文
2022
Ettoumi, Mouna | Jouini, Marouen | Neculita, Carmen Mihaela | Bouhlel, Salah | Coudert, Lucie | Benzaazoua, Mostafa
In Tunisia, phosphate beneficiation from ores by the Gafsa Phosphate Company (GPC) is a water-intensive process that generates large amounts of sludge. Responsible mining minimizes water use and prioritizes its recycling and reuse to limit the impact on water resources. Recovery of water from the phosphate sludge (PS) using the densification with adapted flocculants—a low-energy consuming process—is plausible for efficient management of water resources. The objective of this study was to improve low-cost water recovery from PS produced at the M’Dhilla Mine plant operated by GPC in Tunisia. Representative samples of PS were first collected and characterized for physicochemical and mineralogical properties. To maximize water recovery, densification based on flocculation was then performed using two different flocculants (Slim Floc vs Flomin 905) with different doses (0.1 g/L vs 0.3 g/L), consumption (100–1200 g per ton of dry sludge g/tds), sludge concentration (50 g/L vs 60 g/L), and settling time (15–1200 s). Results showed that PS particles were fine-grained and contained carbonates, silicates, and significant residual fluorapatite (59%) that could be valorized. Up to 91% of water was recovered using anionic flocculant Flomin 905. These findings show an improvement of 24% relative to the current water recovery at M’Dhilla plant (66%) while using a flocculant dose three times lower than the conventional flocculent Sim Floc (0.1 g/L vs 0.3 g/L). The best sludge settlement conditions were obtained with 0.1 g/L Flomin 905 at 600 g/tds and 10 min of settling time. The densification process using Flomin 905 proved efficient in maximizing water recovery (91%) with a consumption of flocculant that could be decreased by up to 70% annually in comparison with Slim Floc, thus decreasing treatment costs by 63%. Results will help to prevent exhaustion of groundwater resources and limit land exploitation while decreasing the volume of settling ponds.
显示更多 [+] 显示较少 [-]A comprehensive review of heavy metal pollution in the coastal areas of Bangladesh: abundance, bioaccumulation, health implications, and challenges 全文
2022
Rakib, MdRefat Jahan | Rahman, Md Asrafur | Onyena, Amarachi Paschaline | Kumar, Rakesh | Sarker, Aniruddha | Hossain, M Belal | Islam, Abu Reza Md Towfiqul | Islam, Md Saiful | Rahman, Md Mostafizur | Jolly, Yeasmin Nahar | Idris, Abubakr M. | Ali, Mir Mohammad | Vēlāyutan̲, T. A. | Sun, Xian
The coastal zone of Bangladesh, with a population density of 1278 people per square kilometer, is under serious threat due to heavy metal pollution. To date, many studies have been conducted on the heavy metal contamination in soils, water, aquatic animals, and plants in the coastal zone of Bangladesh; however, the available information is dispersed. In this study, previous findings on the contamination levels, distributions, risks, and sources of heavy metals in sediments and organisms were summarized for the first time to present the overall status of heavy metal pollution along coastal regions. Earlier research found that the concentrations of various heavy metals (HMs), particularly Co, Cd, Pb, Cu, Cr, Mn, Fe, and Ni in water, sediment, and fish in most coastal locations, were above their permissible limits. High concentrations of HMs were observed in sediments and water, like Cr of 55 mg/kg and 86.93 mg/l in the ship-breaking areas and Karnaphuli River, respectively, in coastal regions of Bangladesh. Heavy metals severely contaminated the Karnaphuli River estuary and ship-breaking area on the Sitakundu coast, where sediments were the ultimate sink of high concentrations of metals. Sedentary or bottom-dwelling organisms like gastropods and shrimp had higher levels of heavy metals than other organisms. As a result, the modified PRISMA review method was used to look at the critical research gap about heavy metal pollution in Bangladesh’s coastal areas by analyzing the current research trends and bottlenecks.
显示更多 [+] 显示较少 [-]A review on solar-powered cooling systems coupled with parabolic dish collector and linear Fresnel reflector 全文
2022
Esfanjani, Pouya | Jahangiri, Sajjad | Heidarian, Ali | Valipour, Mohammad Sadegh | Rashidi, Saman
Solar energy is the most sustainable and free source to manage the world energy demand. One aspect of solar-driven energy supply can be observed in cooling systems. Recently, solar energy-based cooling systems have received many attentions. Solar cooling systems utilizing solar collectors, as the renewable and sustainable-based solution, have the good potentials to overcome the challenges associated with consumption of fossil fuels. In this study, the recent advances about the potentials of dish collectors and linear Fresnel reflectors for the usage in the cooling systems are reviewed. In addition, the solar-powered conventional absorption chiller and cryogenic systems are investigated. Hybrid cooling solar systems and solar-based combined cooling, heating, and power systems are also studied. The hydrogen production in cooling integrated systems and cold thermal energy storage are discussed. In each section, in addition to general description of the system, some explanations about the thermodynamic and economic aspects of the systems are provided. Finally, the main results of the review are summarized and based on the available gaps between the literatures, some suggestions are provided for the future studies. It was found that using solar dish collectors in a hybrid system, designed for the freshwater and LNG production, causes carbon dioxide emissions reduction by 40%, and also increases freshwater and LNG production by 95% and 4.7%, respectively. In the hybrid trigeneration solar-biomass power plants, using the linear Fresnel reflector leads to 29% save in biomass and land.
显示更多 [+] 显示较少 [-]Assessment of spatiotemporal variability and trend analysis of reference crop evapotranspiration for the southern region of Peninsular India 全文
2022
Ramachandra, Jayashree Tenkila | Veerappa, Subba Reddy Nandanavana | Udupi, Dinesh Acharya
Accurate estimation of reference evapotranspiration (ET₀) is an essential requirement for water resource management and scheduling agricultural activities. Several empirical methods have been employed in estimating ET₀ across diverse climate regimes over the past decades. In this study, the Python implementation for estimation of daily and monthly ET₀ values of representative stations of ten agro-climatic zones of Karnataka from 1979 to 2014 using the standard FAO Penman-Monteith method was carried out. The assessment of temporal and spatial variability of monthly ET₀ values across the various agro-climatic zones done by the various statistical measures revealed that the variation in spatial ET₀ values was higher than temporal variation, indicating major difference in ET₀ values was with respect to the stations rather than years under study. The nonparametric Mann-Kendall test conducted at 1% significance level on the annual ET₀ values revealed a statistically significant increasing trend for all the ten stations during the study period. The trend test conducted on the climate variables like mean air temperature, wind speed, relative humidity, and solar radiation signifies their influence on the annual ET₀ values. The magnitude changes in the trends detected by the Theil Sen’s slope indicated that increasing values of mean temperature, solar radiation, and decreasing values of relative humidity predominantly contributed to the annual upward trend in ET₀ values for the 10 stations. A trivial impact of wind speed on annual ET₀ values was observed for the stations. Kalburgi and Udupi stations exhibited a positive ET₀ trend with the highest and lowest annual values among ten stations.
显示更多 [+] 显示较少 [-]A feasibility study on production of concrete blocks using treated municipal solid waste leachate 全文
2022
Esmaeili, Negar | Heidarzadeh, Nima
Increased water demand due to population growth and industrialization has led to increased water consumption. Hence, it is required to find an alternative to water in different industries. Concrete represents a remarkable water-consuming industry. The present study investigates whether the treated leachate of municipal landfills can be employed as a substitute for water in the concrete mixing scheme. For this purpose, concrete samples fabricated at different concentrations of treated leachates were compared to the control sample containing distilled water in terms of unconfined compressive strength (UCS) at the ages of 7 and 28 days. The experimental results revealed treated leachate accelerated the cement setting time by nearly 15 min and increased concrete slumping by 16%. The complete replacement of distilled water with treated leachate decreased UCS by 25% (from 50 to 38 MPa). The scanning electron microscope (SEM) and ultrasonic results showed that a rise in the treated leachate content of concrete increased porosity. Increased porosity would reduce UCS. Leaking of heavy metals existing in the leachate should be also investigated for the solidified matrices. The toxicity characteristic leaching procedure (TCLP) revealed that heavy metals leaching in all the samples are in the acceptable range. Results have shown that the use of leachate up to a concentration of 20% can be used in concrete, and the solidified product can also stabilize the pollutants, successfully. It is a valuable finding because using treated leachate as a practical additive in the concrete can prevent environmental contamination.
显示更多 [+] 显示较少 [-]Fiscal decentralization, government innovation preference, and haze pollution 全文
2022
Yin, Kedong | Gu, Haolei | Huang, Chong
Local governments are the dominant players in haze pollution control; furthermore, financial power reconstruction affects the effectiveness of haze control. Government innovation preference achieves win-win results for environmental protection and economic development by increasing innovation support. Therefore, a moderating variable for government innovation preference was added to the fiscal decentralization effect on haze pollution, and their interactive effect on haze pollution was studied. This study was conducted in 30 provincial regions. Thus, the severity of regional haze pollution differs because of temporal heterogeneity and asynchronous development. Furthermore, we analyzed the impact on haze pollution from the perspectives of the temporal and spatial differences in different regions of China. The results indicate that (1) fiscal decentralization increases haze pollution, while government innovation preferences control it. (2) In a local evaluation model with a diversified background, fiscal decentralization restrains haze pollution, and pollution source complexity reduces government innovation preference’s control pollution function. The interaction term revealed that government innovation preferences had a significant moderating effect. (3) Fiscal decentralization and government innovation preferences control the heterogeneity of haze pollution in different regions.
显示更多 [+] 显示较少 [-]Economic complexity, ICT, biomass energy consumption, and environmental degradation: evidence from Iran 全文
2022
Mehrjo, Amir | Satari Yuzbashkandi, Saeid | Eskandari Nasab, Mohammad Hadi | Gudarzipor, Hadis
Economic complexity, biomass energy consumption, and information communication technology (ICT) have diverse impacts on energy consumption and carbon dioxide (CO₂) emissions. Nevertheless, analysis of these variable effects is not addressed in the previous literature; the antiqueness of this article is stuffing this gap. This study assessed the relationship between gross domestic product (GDP) per capita, biomass consumption, economic complexity index (ECI), ICT, and CO₂ emissions in Iran in 1994–2018. The autoregressive distributed lag (ARDL) model and the quantile regression (QR) econometric technique were used to investigate the factors affecting CO₂ emissions in the tails of the conditional distribution. The share of each influential factor was predicted through the variance decomposition analysis (VD) for the next 10 years. The empirical results showed a long-run relationship between the variables. So, the variables of biomass consumption, ECI, and ICT improve the quality of the environment in Iran by reducing CO₂ emissions, and the per capita GDP variable increases CO₂ emissions. Results suggest no evidence indicating the presence of environmental Kuznets curve (EKC); however, QR demonstrated the existence of EKCs in the lower quantiles of the conditional distribution. The ECI will have the most share to change the CO₂ emissions in the future. The income threshold should be determined at the turning point of the EKC to increase economic development. Moreover, investing in increasing biomass consumption is vital. Policymakers also need to consider strict added value for the export of products.
显示更多 [+] 显示较少 [-]Metal particle seeding on urban surface samples 全文
2022
Kouadio, Emmanuel Kouakou | Goriaux, Mathieu | Laguionie, Philippe | Ruban, Véronique
In order to estimate the resuspension of the particles empirically, it is necessary to carry out a homogeneous distribution of the particles on the tested surfaces. Thus, in many studies, seeding or deposition in experimental chambers is performed to quantify initial concentrations for subsequent resuspension experiments. The current study was carried out to assess metal particle seeding efficiency on four types of urban surfaces (slate, facade coating, tile, and glass) in a test chamber. To achieve this objective, we compared firstly different solubilization techniques of silver polydisperse particles (1.3–3.2 μm and 0.5–1.0 μm) and gold polydisperse particles (Ø˂5 μm) for chemical quantification by ICP-MS. The result showed better yields in the case of gold for all solubilization techniques studied (82% ± 5% to 98% ± 2% for gold versus 23% ± 18% to 84% ± 12% for silver). Based on this result, four seeding tests were carried out with the gold particles (distribution in chamber centered on 1μm). The concentrations seeded on urban surfaces (mean ± SD) varied from 10,900 ± 1,900 μg.m⁻² (facade coating sample) to 1900 ± 390 μg.m⁻² (glass sample). The relative standard deviation of the measured concentrations equaled 9.5% (tested for aluminum foils), which was less than the measurement uncertainty of the recording equipment (≈14%) and reflected good seeding homogeneity. Observations by scanning electron microscopy coupled to microanalysis (SEM-EDX) were in agreement with these conclusions.
显示更多 [+] 显示较少 [-]The asymmetric and multi-scale volatility correlation between global oil price and economic policy uncertainty of China 全文
2022
Jiang, Qisheng | Zheng, Sheng | Cao, Yan | Wang, Zicheng
With the monthly data of WTI oil price and economic policy uncertainty (EPU) of China from January 2000 to August 2020, this paper detailedly investigates the asymmetric volatility correlations between two types of EPU of China and global oil price in different time scales. The empirical results demonstrate that the volatility correlation between EPU of China and West Texas Intermediate (WTI) oil price is mainly reflected in the monetary policy uncertainty (MPU), while that of fiscal policy uncertainty (FPU) is much weaker. Specifically speaking, the volatility correlation between MPU of China and downward WTI oil price is significantly negative in the short-middle term (4–8 months) and changes to positive in the middle-long term (8–16 months), while that of upward WTI oil price is only significantly positive in the long term (16–32 months). Our findings provide a deeper understanding of the oil price-EPU correlation in China, and can be valuable guidance for diversified market participants such as government policy-makers and global investors.
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