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Resultados 5301-5310 de 6,453
Cardiac toxicity of acrolein exposure in embryonic zebrafish (Danio rerio) Texto completo
2020
Arman, Sezgi | İşisağ Üçüncü, Sema
Acrolein is a widely distributed pollutant produced from various sources such as industrial waste, organic combustion, and power plant emissions. It is also intentionally released into irrigation canals to control invasive aquatic plants. Zebrafish (Danio rerio) has a good reputation for being an attractive model organism for developmental and toxicological research. In this study, zebrafish embryos were exposed to acrolein to investigate the cardiotoxic effects. The 96-h LC₅₀ (median lethal concentration) value of acrolein was determined as 654.385 μg/L. Then, the embryos were treated with the sublethal experimental concentrations of acrolein (1, 4, 16, 64, and 256 μg/L) for 96 h. Embryos were examined at 48, 72, and 96 h post-fertilization (hpf). Acrolein affected the cardiac morphology and function of the embryos. Sinus venosus-bulbus arteriosus (SV-BA) distance of 64 μg/L and 256 μg/L acrolein groups was elongated compared with the control samples. Immunostaining with MF20 antibody clearly exhibited that the atrium positioned posterior to the ventricle which indicated cardiac looping inhibition. Histological preparations also showed the mispositioning and the lumens of the chambers narrowed. Acrolein-induced increased heart rate was noted in the 4, 16, 64, and 256 μg/L treatment groups. Taken together, these results indicated that acrolein disrupted the heart development and cardiac function in zebrafish, suggesting that its water-borne risks should be considered seriously.
Mostrar más [+] Menos [-]Correlation between urinary chromium level and semen quality in men attending an andrology laboratory Texto completo
2020
Pokhrel, Gaurab | Shi, Yihao | Wang, Wangcheng | Khatiwada, Shikha Upadhyaya | Sun, Zhongyang | Yan, Jianqiao | Liu, Jihong | Zheng, Dan
Chromium is an essential element that is required for the normal physiology but can be toxic to humans above a certain level. In spite of growing interest in research on chromium exposure to human health consensus about its effect on human, semen quality has not been achieved. The aim of the present study is to evaluate the impact of chromium exposure on semen parameters. A total of 760 males attending andrology laboratory of Tongji Hospital, Wuhan, for routine semen analysis were enrolled and requested to provide semen and urine samples. The urine level of chromium was evaluated using inductively coupled plasma mass spectrometry (ICP-MS), and computer-assisted semen analysis (CASA) was applied to examine semen parameters. Associations between semen parameters and urinary chromium were analyzed by means of multivariate linear regression analysis. Multivariate analysis showed a negative association between the urinary concentrations of chromium and progressive motility (β = − 0.014, p = 0.040) and total motility (β = − 1.077, p = 0.048), while other semen parameters did not show any statistically significant changes. Urinary chromium could influence semen quality parameters and impair male fecundity.
Mostrar más [+] Menos [-]Synergy optimization for the removal of dye and pesticides from drinking water using granular activated carbon particles in a 3D electrochemical reactor Texto completo
2020
Ghanbarlou, Hosna | Pedersen, Nikoline L. | Nikbakht Fini, Mahdi | Muff, Jens
The combination of adsorption on particulate materials and electrochemical oxidation in 3D electrochemical systems is potentially a very efficient process for the treatment of micropollutants in water. This paper presents results on the use of granular activated carbon as particulate material in the process and treatment of the dye 4-nitrosodimethylaniline and pesticides MCPA (2-methyl-4-chlorophenoxyacetic acid), MCPP (2-methyl-4-chlorophenoxypropionic acid), and the pesticide transformation product BAM (2,6-dichloro-benzamide) in drinking water. 4-nitrosodimethylaniline was used to investigate influential factors as loading of GAC in a batch electrochemical setup and strength of the electric field in a flow cell recirculation batch setup. Results showed that compared to previous studies in distilled water, only additive effects were found in batch setup, and higher electric field strength was needed in the flow cell setup to achieve slight synergy (~ 5%). Reasons were likely due to the indirect oxidation pathways mediated by the anodic chloride oxidation induced by the content of chloride in the drinking water. On MCPA, MCPP and BAM synergies from 28 to 38% were measured in the batch setup, but in the flow cell, results ranged from additive effects (~ 0%) up to 70%. Considering the low price and widespread availability of granular activated carbon, the gain in process removal rates achieved in the combined 3D electrochemical reactor is of interest compared to the individual processes.
Mostrar más [+] Menos [-]A mineralogical and chemical investigation of road dust in Philadelphia, PA, USA Texto completo
2020
O’Shea, Michael J. | Vann, David R. | Hwang, Wei-Ting | Gieré, Reto
Road dust was investigated within Philadelphia, a major United States city with a long history of industrial activities, in order to determine pollution levels. Almost all of the investigated minor elements were enriched relative to the continental crust. Furthermore, mean concentrations of Cr, Co, Cu, and Pb were high compared with those reported in cities in other countries. Lead pollution should be investigated further in Philadelphia, where 8 of the 30 sample sites, including those heavily trafficked by civilians, were at or above the EPA’s child safety threshold for Pb in bare soil. High Spearman correlations between Zn and Cu, Zn and Cr, Cu and Cr, and Sn and V, as well as factor analysis of minor elements suggests that the primary sources of these elements were anthropogenic. Potential sources included the breakdown of alloys, non-exhaust traffic emissions, paint, smelting, and industry. We found that higher organic content in road dust may be related to higher traffic densities, which could be due to tire-wear particles. Additionally, higher mean concentrations of Fe, Cr, Cu, and Zn were found at sites with elevated traffic densities. Land use impacted some of the elements not influenced by traffic density, including Co, Sn, and Pb. Bulk mineral content was similar across different land uses and traffic densities and, thus, did not appear to be influenced by these factors. Our research emphasized the complexity of road dust and utilized a more comprehensive approach than many previous studies. This study established fundamental groundwork for future risk assessment in Philadelphia, as it identified several key pollutants in the city. Overall, this assessment serves as an informative reference point for other formerly heavily industrialized cities in the USA and abroad.
Mostrar más [+] Menos [-]Impact of selenium, zinc and their interaction on key enzymes, grain yield, selenium, zinc concentrations, and seedling vigor of biofortified rice Texto completo
2020
Ei, Hla Hla | Zheng, Tengda | Farooq, Muhammad Umer | Zeng, Rui | Su, Yang | Zhang, Yujie | Liang, Yuanke | Tang, Zhichen | Ye, Xiaoying | Jia, Xiaomei | Zhu, Jianqing
Selenium (Se) is an essential micronutrient and important component of oxidase which protects cell membranes, eliminate the role of free radicals in the human body. Se is necessary for low Se rice genotypes and Se deficient areas. Zinc (Zn) is a micro-battalion that affects the growth, development, aging, drought resistance, disease resistance, and many other aspects for rice. The effects of Se and Zn fertilization on Se and Zn concentrations were evaluated including the response of superoxide dismutase (SOD), catalase (CAT) enzymes activity, and grain yield under single Se, Zn, and combined Se-Zn application using R725 rice variety in pot experiment with 8 treatments (0, Zn5, Zn10, Zn15, Se1, Zn5 + Se1, Zn10 + Se1, and Zn15 + Se1) mg/kg of soil and three replications. Moreover, germination% and seedling growth of resulted seeds from this experiment were evaluated for the agronomical benefit of farmers. The results revealed that Se and Zn had a cumulative effect on each other, but more Se increase was activated than Zn under the combined Se-Zn application. Zinc application had the small effect on Zn concentration in the different fractions but the positive effect on carotenoids and the yield (both applied alone and in combination with Se). Single Se application resulted in a positive effect on Zn accumulation in grain and husk with the high effectiveness of Se accumulation and loss during processing. Combined Se-Zn application had positive effect on carotenoids, CAT, grain yield, and total dry matter. Moreover, single Zn and combined Se-Zn application had a positive effect on germination% and seedling growth. Agronomic biofortification with combined Se-Zn supply provided both agronomic and nutritional benefits for rice in the current pot trail. However, as Se preferably accumulated in the edible part as compared to Zn, 1 mg Se/kg fertilization was unsafe for edible purposes according to the national standard of China (0.04–0.3 mg/kg) but could be recommended as medicine.
Mostrar más [+] Menos [-]Apoptosis and DNA damage induced by silica nanoparticles and formaldehyde in human lung epithelial cells Texto completo
2020
Nazarparvar-Noshadi, Mehran | Ezzati Nazhad Dolatabadi, Jafar | Rasoulzadeh, Yahya | Mohammadian, Yousef | Shanehbandi, Dariush
Human exposure to silica nanoparticles (SNPs) and formaldehyde (FA) is increasing and this has raised some concerns over their possible toxic effects on the exposed working populations. Notwithstanding several studies in this area, the combined toxicological effects of these contaminants have not been yet studied. Therefore, this in vitro study was designed to evaluate the SNPs and FA combined toxicity on human lung epithelial cells (A549 cells). The cells were exposed to SNPs and FA separately and in combined form and the single and combined toxicity of SNPs and FA were evaluated by focusing on cellular viability, DNA damage, and apoptosis via MTT, DAPI staining, DNA ladder, and Annexin V-FITC apoptosis assays. The results showed a significant increase in cytotoxicity, DNA damage, and chromatin fragmentation and late apoptotic\necrotic rates in combined treated cells compared with SNPs and FA-treated cells (P value < 0.05). Two-factorial analysis showed an additive toxic interaction between SNPs and FA. Eventually, this can be deduced that workers exposed simultaneously to SNPs and FA may be at high risk compared with exposure to each other.
Mostrar más [+] Menos [-]Comparative study of vermicomposting of garden waste and cow dung using Eisenia fetida Texto completo
2020
Li, Yingkai | Yang, Xiaolei | Gao, Wen | Qiu, Jiangping | Li, Yinsheng
Vermicomposting is the process of composting using worms and is applied in waste management to produce high-quality organic fertilizer. Garden waste (GW) is often mixed with other raw materials for vermicomposting. In the present study, the feasibility of vermicomposting using only GW was investigated in comparison with cow dung (CD). The total nitrogen (TN), total phosphorus (TP), and total potassium (TK) contents and the electrical conductivity increased, while total organic carbon (TOC) and the C/N ratio decreased in both substrates after vermicomposting. The nutrient content (TN, TP, and TK) of the GW vermicompost was promoted less than that in CD. Scanning electron microscopy images and specific surface area analysis showed that the vermicompost was strongly disaggregated and became more compacted and fragmented compared with the raw substrates. No mortality of earthworms was observed in GW; however, the earthworms had a higher mean body weight and reproduction rate in CD than that in GW. There were higher bacterial community richness and diversity in the vermicompost than that in the raw materials, and the dominant phylum species were Proteobacteria, Actinobacteria, and Bacteroidetes. Redundancy analysis demonstrated that TN, C/N ratio, and TOC play an important role in bacterial community dynamics. These data indicate that vermicomposting is a robust process that is suitable for the management of GW.
Mostrar más [+] Menos [-]Toxicological potential of penconazole on early embryogenesis of white mice Mus musculus in either pre- or post-implantation exposure Texto completo
2020
El-Shershaby, Abd El-Fattah M. | Lashein, Fakhr El-Din M. | Seleem, Amin A. | Ahmed, Abeer A.
The present investigation was conducted to evaluate the effect of penconazole (PEN) fungicide on early embryogenesis of white mice. In the first experiment, 48 pregnant females were divided into different groups; the first group is control (G1). The second group (G2) was treated daily with PEN (30-, 20-, 10-, 5-mg/kg BW). The third group (G3) was treated with PEN (5-mg/kg BW; day after the other day). The fourth group (G4) was treated with PEN (2.5-mg/kg BW daily) during pre-implantation stage (from the 1st to the 4th day of gestation). The fifth group (G5) was treated with PEN (2.5-mg/kg BW daily) during post-implantation (from the 5th to the 8th day of gestation). The pregnant females were sacrificed at the 14th day of gestation. In the second experiment, 63 pregnant females were classified into control, PEN-treated during pre-implantation period (2.5-mg/kg BW), and PEN-administered during post-implantation period (2.5-mg/kg BW). Each group was sacrificed at stages E6.5, E7.5, E8.5, E9.5, E11.5, E14.5, and E18.5. The high doses of PEN in the first experiment showed failed pregnancy, foetoresorption, and embryo disorganization. High doses of PEN induce alterations in the uterus tissue at the level of histology and immunohistochemistry for the expression of TGFβ2, TNFR2, Caspase 10, and HSP70. The low doses of PEN in the second experiment showed upregulated expression of TGFβ2, TNFR2, Caspase 10, and HSP70 at stages E6.5 and E7.5. In conclusion, PEN was found to alter the suitable uterine environment for proper implantation and development at the levels of histological and immunohistochemical that could create a risk during the full course of embryogenesis.
Mostrar más [+] Menos [-]Implementation and evaluation of WRF simulation over a city with complex terrain using Alos-Palsar 0.4 s topography Texto completo
2020
Guevara Luna, Marco Andrés | Casallas, Alejandro | Belalcázar Cerón, Luis Carlos | Clappier, Alain
Air quality modeling requires an accurate representation of meteorology, and in cities with complex topography, the performance of meteorological modeling can be improved by using an alternative global digital elevation model (GDEM) such as Alos-Palsar 0.4 s instead of the default elevation data. Bogotá is a city with complex topography geographically located over the Andes Mountains at 2600 m.a.s.l. A reliable meteorological simulation model is critical for performing a suitable air quality modeling in any case of study. Previous researches have been developed using the standard Weather Research and Forecast (WRF) topography (GTOPO 30 s). These studies have been developed with different configurations for the representation of meteorology. The aim of this study is to evaluate Alos-Palsar 0.4 s topography with WRF, and two domain configurations with horizontal spatial resolutions up to 1000 m, to establish a reliable and accurate way to simulate the meteorology in the city of Bogotá. The evaluation quantitative parameters: IOA, r (Pearson), RMSE, MGE, and MB were calculated for the quantitative evaluation of temperature, relative humidity, wind speed, wind direction, and solar radiation. An additional evaluation using Taylor diagrams was performed. Spatial differences were identified in the same locations as well the differences between the elevation from Alos-Palsar 0.4 s and GTOPO30. The results and evaluation suggest that simulations based on Alos-Palsar 0.4 s topography lead to a significant improvement in the meteorology representation by WRF in a region with complex topography such as Bogotá, Colombia.
Mostrar más [+] Menos [-]Stakeholders’ perspective on strategies to promote contaminated site remediation and brownfield redevelopment in developing countries: empirical evidence from Pakistan Texto completo
2020
Ahmad, Naveed | Zhu, Yuming | Shao, Jing | Lin, Hongli
Due to the potential of reducing negative outcomes of brownfields on environment and contribution to urban sustainability, brownfield redevelopment (BR) gained considerable recognition in the more recent era. Comprehensive literature shows that many studies proposed strategies to promote BR in developed nations; however, studies focusing on developing economies are scarce. Therefore, this study intends to identify significant strategies to promote BR in developing countries by taking the case of Pakistan. A comprehensive literature review and expert opinion were commenced to identify potential strategies. Data were collected from the main stakeholders involved in BR process through an empirical questionnaire. The findings revealed that “Low-interest loans and subsidies with the collaboration of government and financial institutions,” “Standardized definition, guidelines, and simplified brownfield process,” “Development of technical and infrastructure support,” “Create investors interest,” “Strengthening remediation technologies R&D” were the five most important strategies to promote BR in Pakistan. Theoretically, the novelty of the current study is to highlight the key strategies to promote BR in developing countries. Practically, the study facilitates governments, urban policymakers, environmentalists, and stakeholders to propose and implement appropriate strategies for promoting BR. Future studies can consider modeling the interactions between strategies and their impact on BR adoption.
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