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Resultados 2731-2740 de 5,151
Iron-impregnated zeolite catalyst for efficient removal of micropollutants at very low concentration from Meurthe river Texto completo
2018
Ayoub, Hawraa | Roques-Carmes, Thibault | Potier, Olivier | Koubaissy, Bachar | Pontvianne, Steve | Lenouvel, Audrey | Guignard, Cédric | Mousset, Emmanuel | Poirot, Hélène | Toufaily, Joumana | Hamieh, Tayssir
In this paper, for the first time, faujasite Y zeolite impregnated with iron (III) was employed as a catalyst to remove a real cocktail of micropollutants inside real water samples from the Meurthe river by the means of the heterogeneous photo-Fenton process. The catalyst was prepared by the wet impregnation method using iron (III) nitrate nonahydrate as iron precursor. First, an optimization of the process parameters was conducted using phenol as model macro-pollutant. The hydrogen peroxide concentration, the light wavelength (UV and visible) and intensity, the iron loading immobilized, as well as the pH of the solution were investigated. Complete photo-Fenton degradation of the contaminant was achieved using faujasite containing 20 wt.% of iron, under UV light, and in the presence of 0.007 mol/L of H₂O₂ at pH 5.5. In a second step, the optimized process was used with real water samples from the Meurthe river. Twenty-one micropollutants (endocrine disruptors, pharmaceuticals, personal care products, and perfluorinated compounds) including 17 pharmaceutical compounds were specifically targeted, detected, and quantified. All the initial concentrations remained in the range of nanogram per liter (0.8–88 ng/L). The majority of the micropollutants had a large affinity for the surface of the iron-impregnated faujasite. Our results emphasized the very good efficiency of the photo-Fenton process with a cocktail of a minimum of 21 micropollutants. Except for sulfamethoxazole and PFOA, the concentrations of all the other microcontaminants (bisphenol A, carbamazepine, carbamazepine-10,11-epoxide, clarithromycin, diclofenac, estrone, ibuprofen, ketoprofen, lidocaine, naproxen, PFOS, triclosan, etc.) became lower than the limit of quantification of the LC-MS/MS after 30 min or 6 h of photo-Fenton treatment depending on their initial concentrations. The photo-Fenton degradation of PFOA can be neglected. The photo-Fenton degradation of sulfamethoxazole obeys first-order kinetics in the presence of the cocktail of the other micropollutants.
Mostrar más [+] Menos [-]Effects of export concentration on CO2 emissions in developed countries: an empirical analysis Texto completo
2018
Apergis, Nicholas | Can, Muhlis | Gözgor, Giray | Lau, ChiKeung Marco
This paper provides the evidence on the short- and the long-run effects of the export product concentration on the level of CO₂ emissions in 19 developed (high-income) economies, spanning the period 1962–2010. To this end, the paper makes use of the nonlinear panel unit root and cointegration tests with multiple endogenous structural breaks. It also considers the mean group estimations, the autoregressive distributed lag model, and the panel quantile regression estimations. The findings illustrate that the environmental Kuznets curve (EKC) hypothesis is valid in the panel dataset of 19 developed economies. In addition, it documents that a higher level of the product concentration of exports leads to lower CO₂ emissions. The results from the panel quantile regressions also indicate that the effect of the export product concentration upon the per capita CO₂ emissions is relatively high at the higher quantiles.
Mostrar más [+] Menos [-]Unexpected potential protective associations between outdoor air pollution and cataracts Texto completo
2018
Choi, Yoon-Hyeong | Park, Sujin | Paik, HaeJung | Kim, MeeKum | Wee, WonRyang | Kim, Donghyun
Air pollution is one of the biggest public health issues, and the eye is continuously exposed to multiple outdoor air pollution. However, to date, no large-scale study has assessed the relationship between air pollutants and cataracts. We investigated associations between outdoor air pollution and cataracts in the Korean population. A population-based cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey, including 18,622 adults more than 40 years of age. The presence of cataracts and their subtypes were evaluated by ophthalmologists. Air pollution data (levels of particulate matter, ozone, nitrogen dioxide, and sulfur dioxide) for the 2 years prior to the ocular examinations were collected from national monitoring stations. The associations of multiple air pollutants with cataracts were assessed by multivariate logistic regression analyses. Sociodemographic factors and previously known risk factors for cataracts were controlled as covariates (model 1 included sociodemographic factors, sun exposure, and behavioral factors, while model 2 further included clinical factors). Higher ozone concentrations were protectively associated with overall cataract which included all subtypes [single pollutant model: 0.003 ppm increase—model 1 (OR 0.89, p = 0.014), model 2 (OR 0.87, p = 0.011); multi-pollutant model: 0.003 ppm increase—model 1 (OR 0.80, p = 0.002), model 2 (OR 0.87, p = 0.002)]. Especially, higher ozone concentrations showed deeply protective association with nuclear cataract subtype [0.003 ppm increase—single pollutant model: model 2 (OR 0.84, p = 0.006), multi-pollutant model: model 2 (OR 0.73, p < 0.001)]. Higher tropospheric ozone concentrations showed protective associations with overall cataract and nuclear cataract subtype in the Korean population.
Mostrar más [+] Menos [-]The environmental impact of informal and home productive arrangement in the jewelry and fashion jewelry chain on sanitary sewer system Texto completo
2018
Salles, FernandaJunqueira | Sato, AnaPaula Sayuri | Luz, MacielSantos | Fávaro, DéborahInês Teixeira | Ferreira, FranciscoJorge | Paganini, Wanderley da Silva | Olympio, KellyPolido Kaneshiro
The outsourcing informal home practices adopted in jewelry and fashion jewelry chain can cause toxic substance elimination in the effluents and raise a concern for its environmental impact. This study evaluates if this informal work alters the concentration of potentially toxic elements (PTEs: As, Cd, Cr total and Cr-VI, Cu, Hg, Ni, Pb, Sn, and Zn) in the sewage network. The sanitary sewage samples (n = 540) were collected in 15 manholes during two campaigns in three different areas of Limeira-SP, Brazil (industrial area, with informal work and without known industrial/informal activity). The sewage sludge (n = 12), raw (n = 12), and treated sewage (n = 12) were collected in two wastewater treatment plants (WWT: AS and TATU) operating with different treatment process. The PTE determination was performed by ICP-OES, direct mercury analysis, and UV–Vis spectroscopy. Cr-VI, Cu, Ni, and Zn were the only elements above the quantification limit. Four samples exceeded Cu or Zn values permitted to be discharged into sewage system; however, the concentration average was lower than that established by Brazilian legislation. A difference was found between values above and below the 75th percentile for campaign and total organic carbon values (p < 0.015). The AS-treated sewage presented low concentrations of Cu (p < 0.05), Zn (p = 0.02), and Ni (p = 0.01) compared to treated sewage from TATU. In the sludge samples, the Cu means exceeded the limits of the Brazilian legislation (1500 mg kg⁻¹) and the Zn results were very close to the limits (2800 mg kg⁻¹). The heterogeneity of the results can indicate the sporadic nature of the PTE’s sanitary disposal. PTEs used in jewelry and fashion jewelry chain may precipitate on the sludge, where presented high concentrations of Cu and Zn which require controlled destination.
Mostrar más [+] Menos [-]Protective role of jaboticaba Plinia peruviana peel extract in copper-induced cytotoxicity in Allium cepa Texto completo
2018
Franscescon, Francini | Mazon, Samara C. | Bertoncello, Kanandra T. | Boligon, Aline A. | Sachett, Adrieli | Rambo, Cassiano L. | Rosemberg, Denis B. | Magro, Jacir Dal | Siebel, Anna M.
Jaboticaba Plinia peruviana (Poir.) Govaerts is a Brazilian berry that presents high levels of polyphenols, which may play a key role in preventing cytotoxic and genotoxic effects of harmful agents. Although copper is an essential micronutrient that plays an important role in organisms, high copper concentrations may trigger toxicity to animals and plants. Here, we investigated whether Plinia peruviana hydroalcoholic extract prevents copper-induced cytotoxicity in Allium cepa root cells. Five different anthocyanins and phenolic compounds were identified in Plinia peruviana extract. Importantly, the exposure to 1.53 mg/L copper for 24 h impaired mitotic index, as well as increased mitosis disturbances and triggered DNA damage. Pre-incubation with Plinia peruviana extract (0.25 g/L and 0.75 g/L) for 3 h prevented copper-induced changes in the mitotic index and reduced the number of abnormal cells. In conclusion, we suggest that Plinia peruviana peel extract has protective effects against cellular and genetic disturbances induced by copper.
Mostrar más [+] Menos [-]RhoG-ELMO1-RAC1 is involved in phagocytosis suppressed by mono-butyl phthalate in TM4 cells Texto completo
2018
Gong, Pan | Chen, Shanshan | Zhang, Lulu | Hu, Yanhui | Gu, Aihua | Zhang, Jingshu | Wang, Yubang
Di-n-butyl phthalate (DBP) is one of the most dominant phthalate esters and is ubiquitous in the environment. Male reproductive toxicity of DBP and its active metabolite mono-butyl phthalate (MBP) has been demonstrated in in vivo and in vitro studies. The objective of this study was to explore the roles of RhoG-ELMO1-RAC1 in phagocytosis disrupted by MBP in TM4 cells. Mouse Sertoli cell lines (TM4 cells) were maintained and treated by various levels of MBP (1, 10, and 100 μM) for 24 h. Then, cells were harvested for further experiments. Phagocytic capacity of TM4 cells was detected by flow cytometry, immunofluorescence, and oil red O staining. RAC1 activity (GTP-RAC1) was measured by RAC1 pull-down assay. Expression of mRNA and protein related to phagocytosis including ELMO1, RhoG, and RAC1 was analyzed by qRT-PCR and Western blots, respectively. MBP inhibited phagocytosis of TM4 cells and downregulated GTP-RAC1 expression and movement to membrane markedly. Furthermore, ELMO1 protein expression was downregulated in a dose-dependent manner after MBP treatments. Additionally, expression of proteins relating to phagocytosis, including RhoG and GTP-RAC1, was decreased significantly, but expression of total-RAC1 remained unchanged. GTP-RAC1 expression increased dramatically after TM4 cells were transfected with ELMO1 or RhoG plasmid, but restored under co-treatments with MBP and ELMO1/RhoG plasmid. This study suggests that MBP can reduce the phagocytosis of Sertoli cells through RhoG-ELMO1-RAC1 pathway.
Mostrar más [+] Menos [-]Redox balance and DNA fragmentation in arsenic-exposed occupational workers from different industries of Pakistan Texto completo
2018
Raza, Maryam | Mahjabeen, Ishrat | Fahim, Muhammad | Malik, Waqar Ahmad | K̲h̲ān, Asadullāh | Kayani, Mahmood Akhtar | Khan, Ayesha | Akram, Zertashia
Occupational exposure accounts for a contact between workers and different toxicants. Present study was designed to measure the arsenic-induced DNA fragmentation and oxidative stress in exposed workers. Blood, hair, and nail samples were collected from welding, brick kiln, furniture, pesticide, and paint industries (n = 50/industry) of Pakistan along with 200 controls. DNA damage was calculated using DNA fragmentation assay. Antioxidant enzymes (CAT, SOD, GPx) were measured using ELISA. Results revealed that arsenic exposure induced DNA fragmentation in brick kiln, furniture, and welding industries. Enzyme activity was reduced in five industries compared to control. In exposed group, significant depletion of enzymes was observed in furniture, welding, and brick kiln workers. Based on age and time of exposure, significant difference was observed in welding and brick kiln group. Smokers of exposed group showed significantly reduced levels of enzymes compared to controls. Arsenic deposition was observed higher in the hair, nail, and blood samples of exposed group (P < 0.001) compared to control. Likewise, lead and cadmium contents were higher in the blood samples of industrial workers compared to control. This study suggests increased trend of cellular damage and oxidative stress in occupational workers profoundly in welding, furniture, and brick kiln industries. Moreover, this study recognizes the contribution of age, exposure time, and smoking status toward arsenic-induced oxidative stress and DNA fragmentation.
Mostrar más [+] Menos [-]Antimicrobial use and antimicrobial resistance in food animals Texto completo
2018
Xiong, Wenguang | Sun, Yongxue | Zeng, Zhenling
Antimicrobials have been widely used in food animals for growth promotion since the 1950s. Antimicrobial resistance emerges in animal production settings and frequently spreads to humans through the food chain and direct contact. There have been international efforts to restrict or ban antimicrobials used for both humans and animals. Denmark has taken positive strides in the development of a comprehensive database DANMAP to track antimicrobial usage and resistance. Although food animals are sources of antimicrobial resistance, there is little evidence that antimicrobial resistance originates from food animals. This review comprehensively introduces the history and trends of antimicrobial use, the emergence and spread of antimicrobial resistance in food animals provides suggestions to tackle the problems of the spread of antimicrobial resistance.
Mostrar más [+] Menos [-]Industrial air pollution and low birth weight: a case-control study in Texas, USA Texto completo
2018
Gong, Xi | Lin, Yan | Zhan, F Benjamin
Many studies have investigated associations between maternal residential exposures to air pollutants and low birth weight (LBW) in offspring. However, most studies focused on the criteria air pollutants (PM₂.₅, PM₁₀, O₃, NO₂, SO₂, CO, and Pb), and only a few studies examined the potential impact of other air pollutants on LBW. This study investigated associations between maternal residential exposure to industrial air emissions of 449 toxics release inventory (TRI) chemicals and LBW in offspring using a case-control study design based on a large dataset consisting of 94,106 LBW cases and 376,424 controls in Texas from 1996 to 2008. Maternal residential exposure to chemicals was estimated using a modified version of the emission-weighted proximity model (EWPM). The model takes into account reported quantities of annual air emission from industrial facilities and the distances between the locations of industrial facilities and maternal residence locations. Binary logistic regression was used to compute odds ratios measuring the association between maternal exposure to different TRI chemicals and LBW in offspring. Odds ratios were adjusted for child’s sex, birth year, gestational length, maternal age, education, race/ethnicity, and public health region of maternal residence. Among the ten chemicals selected for a complete analysis, maternal residential exposures to five TRI chemicals were positively associated with LBW in offspring. These five chemicals include acetamide (adjusted odds ratio [aOR] 2.29, 95% confidence interval [CI] 1.24, 4.20), p-phenylenediamine (aOR 1.63, 95% CI 1.18, 2.25), 2,2-dichloro-1,1,1-trifluoroethane (aOR 1.41, 95% CI 1.20, 1.66), tributyltin methacrylate (aOR 1.20, 95% CI 1.06, 1.36), and 1,1,1-trichloroethane (aOR 1.11, 95% CI 1.03, 1.20). These findings suggest that maternal residential proximity to industrial air emissions of some chemicals during pregnancy may be associated with LBW in offspring.
Mostrar más [+] Menos [-]Morphology, molecular structure, and stable carbon isotopic composition of black carbon (BC) in urban topsoils Texto completo
2018
Zong, Yutong | Xiao, Qing | Lu, Shenggao
Urban soils contain significant amounts of black carbon (BC) from biomass and fossil fuel combustion and regard to be a pool of BC. BC in urban soils has multiple effects on environmental processes in urban system, such as global climate change, air quality, and public health. Urban topsoil samples (0–10 cm) were collected from Anshan, Liaoning Province, northeast China, which is one of the most important old steel industrial bases in China. The BC in urban topsoils was extracted using the density method. Their chemical composition, morphology, molecular structure, and stable carbon isotopic composition were examined using elemental analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and stable carbon isotope (δ¹³C). Elemental analysis shows that carbon content in the BC of studied soils ranged from 64.5 to 78.4%, with the average more than 70%. The O/C atomic ratio of BC is on average 0.18. The BC particle displays different morphology, including porous spherical, irregular porous fragmentary, and blocky shapes. The porous spherical BC particles has atomic molar O/C ratio determined by SEM-EDS ranging from 0.04 to 0.37. XRD indicates that BC exists in mainly combining with mineral phases hematite (Fe₂O₃), kaolinite (Al₂Si₂O₅(OH)₄), quartz (SiO₂), and calcite (CaCO₃). The FTIR spectra of BC particles show major bands at approximately 3400 cm⁻¹ (O–H), 2920 cm⁻¹ (C = H), 1600 cm⁻¹ (C = C), 1230 cm⁻¹ (C = O), and 1070 cm⁻¹ (C = O). The stable carbon isotope (δ¹³C) of BC ranges from −24.48 to −23.18‰ with the average of −23.79 ± 0.39‰. The concentration of BC in the industrial area is significantly (p < 0.05) higher than that in the roadside area. The BC of industrial area is characterized by porous spherical structure, suggesting that they are mainly derived from fossil fuel combustion. Results indicated that a combination of atomic O/C ratio, porous structure, and stable carbon isotopic (δ¹³C) of BC could reflect effectively the origin of BC in urban topsoils. It could conclude that BC in Anshan urban topsoil was mainly from fossil fuel combustion.
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