Characterization, possible sources and health risk assessment of PM2.5-bound Heavy Metals in the most industrial city of Iran

Air pollution associated with particulate matters results in different types of disease including allergy, lung destruction, heart failure, and related problems. This study has been designed and performed to examine the concentration of PM2.5-bound heavy metals, risk assessment, possible sources and effect of meteorological parameters on 17 sites of the air of the most industrial city of Iran (Karaj) in 2018-19. For this purpose, four samples were taken from every point of Karaj air over one year using a pump (Leland Legacy (SKC)) with flow rate of 3 L/min on PTFE filter for 24 h. Overall, 68 samples of PM2.5-bound heavy metals were collected. Note that during the sampling, atmospheric parameters including temperature, pressure, humidity, and wind speed were regularly recorded using PHB318 portable device. In examining the chemical composition of these particles, the concentration of metals (Al-Zn- Ar-Cd-Cr-Cu-Fe-Hg-Mn-Ni-Pb) was determined after digestion of the collected samples and through injection into ICP-OEC device. The results indicated that the mean annual concentration of PM2.5 particles range from 21.84 to 72.75 µg/m3. The mean concentration of heavy metals lied within the range of 25.63 to 336.27 ng/m3. Among heavy metals, the maximum concentration belonged to aluminum (277.95 ng/m3) and iron (336.27 ng/m3), which are known as elements with a ground source (sources such as car fuels, exhaust gases, decorative materials, batteries, indoor smoking, the paint used for painting walls, erosion and corrosion of rubber of cars). Meanwhile, there was a positive relationship between heavy metals and temperature(r: 0.418, p < 0.019), pressure (r: 0.184, p < 0.0.402), as well as wind speed (r: 0.38, p < 0.017), while an inverse relationship was observed with relative humidity (r: -0.219, p < 0.018). The ecological risk of the metals calculated was very notable, with the maximum environmental risk being related to cadmium in children (6.61) and manganese in adults (0.82). The largest HQ in children and adults was associated with Cr. Finally, ILCR values for cadmium in both children (1.19 E-04) and adult (4.81 E-04) groups indicated high risk of developing cancer in humans

Monitoring of airborne asbestos fibers in an urban ambient air of Mashhad City, Iran: levels, spatial distribution and seasonal variations

Asbestos, as with other pollutants in the air, has adverse effects on the health of human beings and animals. Today, the relationship between presence of asbestos fibers in the air breathed by humans and developing serious diseases such as lung cancer (asbestosis) and mesothelioma has been proven. The objectives of this study were to monitor the levels of asbestos fibers in ambient air of Mashhad, Iran during 2018, and to draw its Geographic Information System (GIS) distribution map for the city. In this descriptive study, 13 sampling points in Mashhad city were chosen. Sampling of asbestos was carried out for 3 hour during summer and winter at 2018. Sampling of asbestos was performed using MCE (Mixed Cellulose Ester) membrane filters (pour size 0.45 µm; diameter: 25 mm) and cassette holder and peripheral pump. The samples were the analyzed by the phase contrast microscopy (PCM) method (NIOSH7400). Also, to investigate the type of asbestos and for more accurate counting of fibers, Scanning Electron Microscopy (SEM) analysis was utilized. Meteorological parameter were recorded through portable devices. To draw the graphs, Excel, R and Arc GIS software were used. Results showed that the mean asbestos fiber concentrations were equal to 11.40 ± 2.14 and 14.38 ± 2.52 f/L in summer and winter, respectively. The maximum level of asbestos fiber was detected in the station of Baitolmoghaddas square by 26.64 ± 2.14 and 19.3 SEM f/L in winter and summer, respectively. High concentration of asbestos fiber observed in this study can be attributed to the heavy traffic, the presence of prominent industries in the vicinity of the study area, and topographic features. The results from this research recommends that suitable controlling policies should be regulated to reduce both ambient air asbestos and its adverse health endpoints in Mashhad. © 2020, Springer Nature Switzerland AG

A novel idea to increase the performance of a wheat flour cyclone separator: Controlling the reverse flow

In this study, as a novelty, the reverse flow effect on a wheat flour cyclone performance was evaluated. A computational fluid dynamics (CFD) simulation was realized using a Reynolds stress turbulence model. Also, particle–air interactions were modeled applying a discrete phase model. Besides the experimental measurement, the numerical simulation was conducted in a main (without reverse flow) and six various reverse flow levels (I = 0.0385 m3 s−1, II = 0.0396 m3 s−1, III = 0.0484 m3 s−1, IV = 0.0583 m3 s−1, V = 0.0704 m3 s−1, and VI = 0.0836 m3 s−1) by CFD. The validation between pressure drop in experimental data and numerical results revealed a good agreement with a maximum deviation of 8.2%. Cyclone performance including pressure drop and separation efficiency was assessed in the mentioned reverse flow levels. Moreover, velocity field, centrifugal force, and turbulence parameter were evaluated, comprehensively. It was found that the flour separation efficiency increased with enhancing the reverse flow level to IV = 0.0583 m3 s−1, but decreased with a sharp slope in the reverse levels of V = 0.0704 m3 s−1 and VI = 0.0836 m3 s−1

Development and implementation of water safety plans for groundwater resources in the southernmost city of West Azerbaijan Province, Iran

The transfer of water from the source to the consumption point is always associated with the possibility of contamination in any of its various components. To resolve this problem, the World Health Organization has considered a water safety plan. The purpose of this study is to implement water safety plan in the water supply system of Bukan city. This study was performed on Bukan’s water supply system in 2019–20 using a software to guarantee the quality of the water safety plan and the WHO and IWA guidelines. The software checklists were prepared and after confirming the validity of the translation and its facial and content validity, it was completed based on the records of the Water and Sewerage Company and interviews with experts. Out of a total of 440 points of full-application of the program and 392 points for the reviewed phases, 183.6 points were acquired and 43.7% of WSP-coordinated implementation was observed. The highest percentage of WSP-coordinated implementation (75.2%) was assigned to the validation stage with the highest point, and the support program stage had the lowest percentage of performance (1.1%). Among the major components of the water supply system, the final consumption point received the most attention from the system. Given the lifespan of the introduction and use of WSP in the world, it was expected that better results would be obtained from evaluating the implementation and progress of this approach in Bukan’s water supply system. However, the implementation rate of this program in this city compared to other cities in Iran, showed that according to the implementation time (one year), the obtained results are relatively convincing and good and the water supply system has a moderate level of safety

Load characteristics and inhalation risk assessment of benzene series (BTEX) pollutant in indoor air of Ghalyan and/ or cigarette cafes compared to smoking-free cafes

To determine the concentration of benzene series (BTEX) compounds, 33 samples were collected from indoor air of Ghalyan cafés (GHC), cigarette cafés (CC) and smoking-free cafés (SFC) in Bushehr city, Iran, and analyzed using gas-chromatography - flame ionization detector (GC-FID). The results of this study indicated that the mean±SD values of ΣBTEX in GHC, CC and SFC cafés were 19.46 ± 6.07, 11.34 ± 5.21 and 2.26 ± 0.76 mg/m3, respectively. The mean concentration of BTEX in the cafés with fruit-flavored tobacco was significantly higher than those in traditional cafés (p < 0.05). According to path analysis, the number of active waterpipe heads had the maximum impact on the production of pollutants inside the cafés. The results also indicated that the risk of exposure to BTEX in smoking cafés in Bushehr was very high; it can develop serious carcinogenic and noncarcinogenic risks

Distinct Regions of the Large Extracellular Domain of Tetraspanin CD9 Are Involved in the Control of Human Multinucleated Giant Cell Formation

Multinucleated giant cells, formed by the fusion of monocytes/macrophages, are features of chronic granulomatous inflammation associated with infections or the persistent presence of foreign material. The tetraspanins CD9 and CD81 regulate multinucleated giant cell formation: soluble recombinant proteins corresponding to the large extracellular domain (EC2) of human but not mouse CD9 can inhibit multinucleated giant cell formation, whereas human CD81 EC2 can antagonise this effect. Tetraspanin EC2 are all likely to have a conserved three helix sub-domain and a much less well-conserved or hypervariable sub-domain formed by short helices and interconnecting loops stabilised by two or more disulfide bridges. Using CD9/CD81 EC2 chimeras and point mutants we have mapped the specific regions of the CD9 EC2 involved in multinucleated giant cell formation. These were primarily located in two helices, one in each sub-domain. The cysteine residues involved in the formation of the disulfide bridges in CD9 EC2 were all essential for inhibitory activity but a conserved glycine residue in the tetraspanin-defining ‘CCG’ motif was not. A tyrosine residue in one of the active regions that is not conserved between human and mouse CD9 EC2, predicted to be solvent-exposed, was found to be only peripherally involved in this activity. We have defined two spatially-distinct sites on the CD9 EC2 that are required for inhibitory activity. Agents that target these sites could have therapeutic applications in diseases in which multinucleated giant cells play a pathogenic role

A highly carbon-efficient and techno-economically optimized process for the renewable-assisted synthesis of gas to liquid fuels, ammonia, and urea products

Carbon dioxide conversion into beneficial products has received very much attention in recent years to decrease industrial CO2 emissions. In this context, integration of gas to liquids (GTL) process with an iron-based Fischer-Tropsch (FT) reactor with ammonia and urea synthesis plants was investigated. The main motivation of the proposed integration is to reuse a released CO2 stream from the GTL process and to enhance the commercial process economy. The required hydrogen for ammonia comes from polymer electrolyte membrane (PEM) electrolyzers running by solar power. Latin hypercube design (LHD) approach was applied to model the profitability and carbon efficiency of the process. Optimization was conducted to maximize the carbon efficiency and profit index of the overall process using the model-based calibration (MBC) toolbox of MATLAB. The results demonstrated that at the optimum case, the proposed integration is capable of producing 48 t/h of urea and also utilizing about 35 t/h of CO2 produced in the GTL process. The results were compared with another configuration in which a cobalt-based FT reactor was integrated with ammonia and urea processes. The results suggest that profitability, carbon efficiency, and urea production of the process configuration with a Co-based FT reactor is higher than the iron-based configuration while the wax production rate of the iron-based configuration is higher than that of the Co-based process. Techno-economic feasibility study of the zero CO2 emission process represents that the carbon efficiency of around 100% could be obtained

Maximizing the profitability of integrated Fischer-Tropsch GTL process with ammonia and urea synthesis using response surface methodology

© 2019 Elsevier Ltd. The integration of a natural gas to liquids (GTL) process with ammonia and urea synthesis units was conducted to utilize the emitted CO2 of the GTL process for the urea synthesis. The feedstocks of the ammonia synthesis unit including hydrogen and nitrogen were provided by a polymer electrolyte membrane (PEM) electrolyzer and air separation unit (ASU) of the GTL process, respectively. The required power for the PEM modules was assumed to be supplied by the surplus generated power of the GTL process. To enhance the overall carbon efficiency and profitability of the three processes, the emitted CO2 from the GTL process was utilized in the urea synthesis unit. Multi-objective optimization approach was conducted to determine the optimal values of carbon efficiency and wax production rate of the GTL process. Objective functions were calculated by response surface methodology with second-order polynomial regression. The degrees of freedom were defined as follows: Unpurged ratio of recycled tail gas from Fischer-Tropsch (FT) reactor, recycle ratio of the GTL tail gas to the FT reactor, CO2 removal percentage from the GTL process synthesis gas (syngas) section, steam to carbon ratio to pre-reformer, molar flow of feed to the ammonia synthesis unit, and CO2 intake to the urea unit. The presented integration results in the production of about 434,000»tonnes/year urea in addition to the FT-derived products. 13.71% (37»tonnes/h) of the produced CO2 in the GTL process is utilized in the urea production unit and the profitability of the integrated process is enhanced by 8%

Effect of direct dissipative coupling of two competing modes on intensity fluctuations in a quantum-dot-microcavity laser

We investigate two-mode photon correlations in a quantum-dot-microcavity laser with special emphasis on the effects induced by a direct coupling of two competing modes due to the dissipative character of the laser resonator. Numerical results based on a microscopic semiconductor theory reveal an enhanced autocorrelation of both modes and an enhanced anticorrelation between the modes. A detailed analysis is given in terms of dark and bright modes. It is shown that above the lasing threshold the original modes build up a bright mode coupled to the quantum dots and a dark mode, which interacts only indirectly with the quantum dots. We demonstrate that a populated dark mode can enable an efficient transfer of photons between the two original cavity modes, mediating an effective coupling between them