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Resultados 3031-3040 de 4,924
Fate of 14C-acetyl sulfamethoxazole during the activated sludge process
2019
Geng, Chunnu | Zhuang, Yujia | Bergheaud, Valérie | Garnier, Patricia | Haudin, Claire-Sophie
Compared to antibiotic parent molecule, human metabolites are generally more polar and sometimes not less toxic in wastewater. However, most researches focus on the fate of parent molecule. Therefore, behaviors of human metabolites are little known. Moreover, though much has been done on the fate of antibiotics during activated sludge process, there are still some limitations and gaps. In the present study, [Ring-¹⁴C] acetyl sulfamethoxazole (¹⁴C-Ac-SMX) was used to investigate the fate of human metabolite of SMX during activated sludge process at environmentally relevant concentration. At the end of 216 h, 3.1% of the spiked activity in the initial aqueous phase was mineralized, 50% was adsorbed onto the solid phase, and 36.5% still remained in the aqueous phase, indicating that adsorption, not biodegradation, was the main dissipation pathway. In the existence of microbial activities, accumulation into the solid phase was much higher, which was less bioavailable by chemical sequential extraction. The multimedia kinetic model simultaneously depicted the fate of Ac-SMX in the gas, aqueous, and solid phases, and demonstrated that microbially accelerated accumulation onto the solid phase was attributed to lower desorption rate from the solid phase to the aqueous phase, where adsorption rate was not the key factor. Therefore, Ac-SMX cannot be efficiently mineralized and remain in the aqueous or the solid phases. The accumulation in the solid phase is less bioavailable and is hard to be desorbed in the existence of microbial activities, and should not be easily degraded, and may lead to the development of antibiotic-resistant bacteria and genes after discharge into the environment.
Mostrar más [+] Menos [-]Spatial and temporal variations of volatile organic compounds using passive air samplers in the multi-industrial city of Ulsan, Korea
2019
Kim, Seong-Joon | Kwon, Hye-Ok | Lee, Myoung-In | Seo, Yongwon | Choi, Sung-Deuk
The source-receptor relationship of volatile organic compounds (VOCs) is an important environmental concern, particularly in large industrial cities; however, only a few studies have identified VOC sources using high spatial resolution data. In this study, 28 VOCs were monitored in Ulsan, the biggest multi-industrial city in Korea. Passive air samplers were seasonally deployed at eight urban and six industrial sites. The target compounds were detected at all sites. No significant seasonal variations of VOCs were observed probably due to the continuous emissions from major industrial facilities. Benzene, toluene, ethylbenzene, xylenes, and styrene accounted for 66–86% of the concentration of Σ₂₈ VOCs. The spatial distribution of the individual VOCs clearly indicated that petrochemical, automobile, non-ferrous, and shipbuilding industries were major VOC sources. Seasonal wind patterns were found to play a role in the spatial distribution of VOCs. Diagnostic ratios also confirmed that the industrial complexes were the dominant VOC sources. The results of principal component analysis and correlation analyses identified the influence of specific compounds from each industrial complex on individual sites. To the best of our knowledge, this is the first comprehensive report on the seasonal distribution of VOCs with high spatial resolution in a metropolitan industrial city in Korea.
Mostrar más [+] Menos [-]α-Amylase and α-glucosidase inhibitor effects and pancreatic response to diabetes mellitus on Wistar rats of Ephedra alata areal part decoction with immunohistochemical analyses
2019
Ben Lamine, Jihene | Boujbiha, Mouhamed Ali | Dahane, Sabra | Cherifa, Amal Ben | Khlifi, Aida | Chahdoura, Hassiba | Yakoubi, Mouhamed Taher | Ferchichi, Salima | El Ayeb, Nacer | Achour, Lotfi
Ephedra alata, known as a medicinal plant in China, was used in this study as aqueous extract from aerial parts, for diabetes mellitus treatment. This study was carried out on two parts, in vitro, we tested the effect of the studied extract on the inhibition of α-glucosidase and α-amylase activities, and in vivo on Wistar male rats receiving alloxan intraperitoneally at a rate of 125 mg/kg. Extract (100, 200, and 300 mg/kg of body weight) was administrated for 28 days by oral gavage. Blood glucose, amylase, lipase, and lipid profile level were determined. Oxidative stress was evaluated by enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and by estimation of lipid peroxidation and protein carbonyl (PC) level. Histopathological changes in pancreas were investigated under photonic microscopy using immunohistochemical procedure. Our findings showed that aqueous extract inhibited in vitro both α-glucosidase and α-amylase activities and its use in vivo at 300 mg/kg of body weight restored pancreas weight and weight gain, ameliorated significantly (p ˂ 0.05) biochemical parameters; it prevented the increase in lipid and protein oxidation and the decrease in enzymatic and non-enzymatic defense system. Histological study of treated animals showed a comparable healed regeneration of beta cells.
Mostrar más [+] Menos [-]Enhanced performance of alkali-modified Bi2WO6/Bi0.15Ti0.85O2 toward photocatalytic oxidation of HCHO under visible light
2019
Huang, Qiong | Ye, Juan | Si, Han | Ruan, Jiaxin | Xu, Mengxin | Yang, Bo | Tao, Tao | Zhao, Yunxia | Chen, Mindong
Photocatalytic oxidation of formaldehyde (HCHO) is considered as one of the promising ways to resolve indoor air HCHO pollution. TiO₂ has been well known as the most extended application in photocatalysis due to its strong oxidizing ability and stability. Owing to high activity under visible light irradiation, TiO₂ and Bi₂O₃ doping mixed with Bi₂WO₆ was analyzed in this study. The formation of two kinds of heterojunction caused efficient charge separation, leading to the effective reduction in the recombination of photo-generated electron and hole. The special structure and enhanced performance of these catalysts were analyzed. For the first time, the loading of alkali salts was researched for photocatalytic oxidation. In order to understand the reaction mechanism of alkali salts enhanced effects, the catalysts were investigated by using BET, XRD, UV–Vis, FT-IR, SEM, and XPS. The results found more than 2 wt% of Na₂SO₄ loading and the mixed methods with different solutions were key factors affecting the performance of catalysts. Nearly 92% HCHO conversion could be completed over Bi₂WO₆/Bi₀.₁₅Ti₀.₈₅O₂ (Na₂SO₄), and the concentration of HCHO was only 0.07 mg/m³ for 24 h, which was below the limit of specification in China. The results also indicated that the solution mixing method was more favorable to increase the HCHO conversion due to decrease the size of Bi₀.₁₅Tᵢ₀.₈₅O₂ particles. The catalysts with Na₂SO₄ loading provided more surface-adsorbed oxygen that facilitated the desorption of CO₂ and markedly increased the photocatalytic oxidation of HCHO. Graphical abstract Plausible mechanism over W-Bi2WO6/ Bi0.15Ti0.85O2-Na2SO4 (1:4) catalysts
Mostrar más [+] Menos [-]Pea cultivar Blauwschokker for the phytostimulation of biodiesel degradation in agricultural soil
2019
Hawrot-Paw, Małgorzata | Ratomski, Patryk | Mikiciuk, Małgorzata | Staniewski, Jacek | Koniuszy, Adam | Ptak, Piotr | Golimowski, Wojciech
Phytoremediation is a cost-effective and ecologically friendly process that involves the use of plants to uptake, accumulate, translocate, stabilize, or degrade pollutants. The present study was conducted to demonstrate the potential of pea (Pisum sativum L. spp. sativum) cultivar Blauwschokker to phytostimulate biodiesel degradation in an agricultural soil, considering the influence of biological remediation on selected physiological parameters of plants and the amount and activity of soil microflora. Biodiesel was spiked into soil in dose of 50 g kg⁻¹ of dry mass soil. The results of the study showed that the rate of biodiesel degradation in the vegetated soil was higher than that occurring by natural attenuation. At the same time, biodiesel showed a positive effect on the growth, development, and activity of soil bacteria and fungi. Moreover, the obtained results showed an improvement in physiological parameters of plants, including an increase in chlorophyll a and total chlorophyll content and higher relative water content in leaves in the presence of biodiesel.
Mostrar más [+] Menos [-]Dental health status and its indicators in adult Brazilian Indians without exposition to drinking water fluoridation: a cross-sectional study
2019
Montanha-Andrade, Katia | Maia, Wolf | Pimentel, Ana Caroline Pereira | Arsati, Ynara Bosco De Oliveira Lima | Santos, Jean Nunes Dos | Cury, Patricia Ramos
Water fluoridation is considered a cost-effective and practical method for controlling and preventing dental caries in the general population. The objective of this study was to evaluate the dental health status and risk indicators for dental caries in adult Brazilian Indians without exposition to dental caries–preventive effects of water fluoridation. Decayed (DT), missing (MT), and filled (FT) permanent teeth (DMFT), as well as plaque index, unstimulated salivary flow rate, salivary buffering capacity, and fasting blood glucose were examined in 225 adult Indians. Smoking habits and sociodemographic data were evaluated using a structured questionnaire. Drinking water samples from 10 Indian villages were analyzed for the natural fluoride concentration. The mean DMFT was 10.33 ± 6.91 (DT, 4.19 ± 3.99; MT, 4.99 ± 5.64; FT, 1.14 ± 1.75). DMFT index ≥ 9 was associated with age ≥ 35 years (p = 0.000), lower education (p = 0.03), and plaque index > 40% (p = 0.003). DT was associated only with plaque index (p = 0.03). MT was associated with age (p < 0.001) and plaque index (p = 0.01). FT was negatively associated with age (p = 0.02) and income (p = 0.02). Fluoride concentration varied from 0.01 to 0.07 mg/L and was not associated with dental health status (p ≥ 0.29). In conclusion, poorer dental health status was associated with older age, higher plaque index, and lower education and income levels. The fluoride level in the drinking water of Kiriri villages was lower than the level recommended for preventing dental caries. Water fluoridation may be recommended for this population.
Mostrar más [+] Menos [-]Growth, accumulation, and antioxidative responses of two Salix genotypes exposed to cadmium and lead in hydroponic culture
2019
Xu, Xiaohan | Yang, Baoshan | Qin, Guanghua | Wang, Hui | Zhu, Yidan | Zhang, Kaizhen | Yang, Hanqi
Cd and Pb are a toxic environmental pollutant, and their elevated concentrations in the waters and soils could exert detriment effects on human health by food chain. In order to evaluate the capacity to heavy metal accumulation and the physiochemical responses of two Salix genotypes, a 35-day hydroponic seedling experiment was implemented with Salix matsudana Koidz. ‘Shidi1’ (A42) and Salix psammophila C. ‘Huangpi1’ (A94) under different concentrations of Cd (15 and 30 μM) or Pb (250 and 300 μM). The results showed that the biomass of A94 severely reduced more than that of A42. The accumulation ability of Cd in different plant organs followed the sequence of leaves > roots > stems. Pb primarily accumulated in the roots for both Salix genotypes (54.27 mg g⁻¹ for A42 and 54.52 mg g⁻¹ for A94). Translocation factors based on accumulation (TF′) for Cd were more than 8.0, while TF′s for Pb were less than 1.0 in both A42 and A94, implying they could be applied in the phytoremediation of Cd-contaminated sites due to their stronger ability to Cd phytoextraction. The stress of Cd or Pb significantly increased malondialdehyde (MDA) contents and increased photosynthetic rates in leaves of two Salix genotypes. Transpiration rates of willow were positively correlated with its Cd translocation. Both catalase (CAT) and peroxidase (POD) activities were suppressed, while the superoxide dismutase (SOD) was boosted with increasing Cd and Pb levels in the leaves and roots of the two willow genotypes, suggesting SOD plays an important role in the removal of ROS. The inconsistency of the changes in enzyme activity suggests that the integrated antioxidative mechanisms regulate the tolerance to Cd and Pb stress.
Mostrar más [+] Menos [-]Air pollution, output, FDI, trade openness, and urbanization: evidence using DOLS and PDOLS cointegration techniques and causality
2019
Ponce, Pablo | Alvarado, Rafael
Globalization has led countries to a strong interdependence among them, which is reflected in trade and capital flows. Simultaneously, in recent decades, the world is rapidly urbanizing. This dynamic has generated a process of economic growth with serious consequences for the environment, particularly in air quality. In this context, the objective of this research is to examine the causal link among carbon dioxide emissions per capita as a measure of air pollution, real per capita output, FDI, trade openness, and urbanization in 100 countries during 1980–2017. First, we used the cointegration test of Pedroni (JAMA 61:653–670, 1999) and Westerlund (JAMA 69:709–748, 2007) to find the equilibrium long and short term, respectively, and the Dumitrescu and Hurlin (JAMA 29:1450–1460, 2012) test to verify the direction of causality among the series. Second, we estimate the strength of the cointegration vector for individual countries through a dynamic ordinary least squares model (DOLS), and for country groups using a dynamic panel model with ordinary least squares (PDOLS). The results found indicate the existence of short- and long-term equilibrium among the variables globally and by groups of countries. The strength of the cointegration vector is strong in high and middle-high-income countries. At a global level, the results of the causality test suggest the existence of a unidirectional causal relationship that goes from output, urbanization, and FDI to air pollution, and a bidirectional relationship among trade and air pollution. These results are sensitive to the inclusion of the level of development of the countries. Our results suggest that the mechanisms to increase output, along with commercial and FDI flows, and urbanization are factors that play a relevant role in the determination of air pollution. Consequently, public policies should take these aspects into account in efforts to mitigate air pollution.
Mostrar más [+] Menos [-]Criteria and aldehyde emissions from a diesel Euro V engine using diesel/biodiesel blends in Brazil
2019
Bório, Harlen Feijó | Penteado, Renato | Daemme, Luiz Carlos | Godoi, Ricardo | Errera, Marcelo R. | Corrêa, Sergio Machado
The Brazilian legislation does not establish limits or methodology for the measurement of aldehydes in the exhaust of heavy diesel engines. No conclusive studies on aldehyde emissions by such engines have been found in the literature available. This work measured the aldehyde emissions from a P7 diesel cycle engine (EURO V), which was tested on an engine test bench according to ETC (European Transient Cycle) and ESC (European Stationary Cycle) cycles using fuels with 5, 7 and 20% v/v of biodiesel and 10 and 500 ppm of sulphur. The results showed that biodiesel participation in the mixture did not significantly affect the aldehyde emissions of the tested engine and that the emission level generated in the ETC cycle is higher than that obtained with the ESC cycle. The diesel content in the blend was weakly and negatively correlated with the pollutant emissions, and the inverse pattern was observed for biodiesel. This finding indicates that an increase in biodiesel content causes a slight increase in pollutant emissions. Regarding the sulphur content, positive correlations between the sulphur content and particulate matter, NOx, CO and total hydrocarbon emissions were observed. When comparing the test cycles, the results were significantly different, with higher values for the ETC cycle.
Mostrar más [+] Menos [-]Financial liability for environmental damage: insurance market in Italy, focus on Veneto region experience
2019
Staccione, Andrea | Mysiak, Jaroslav | Ostoich, Marco | Marcomini, Antonio
Making good environmental damage caused by industrial accidents and restoring impaired ecosystems may be associated with high costs. The European Environmental Liability Directive requires that environmental damage is prevented or remediated and confers financial liability on operators responsible for the activities that caused the damage. The directive encourages adoption of financial risk instruments for environmental liability, ensuring that operators stand up for their responsibilities. We analyse the risk financing instruments for environmental liability in Italy, with emphasis on waste treatment and disposal plant management in Venice Metropolitan City, where financial guarantees and environmental insurance are mandatory. The regional legislation obliges operators of waste treatment plants to seek financial protection through financial guarantees and environmental insurance. We have conducted online survey and in-depth interviews with both suppliers and users of financial protection instruments. On national level, the relatively high environmental consciousness is countered by a low perception of risk and subsequently very low penetration of financial security instruments. Among the identified barriers, we have singled out a limited knowledge of cumulative and long-lasting impacts of industrial activities on environment and ecosystems. Financial and insurance are well developed, but a deep support for specific risk identification and coverage lacks. A closer cooperation between public and private sector can be an opportunity to foster the adoption of these instruments and to improve the coverage of public costs for environmental restoration, due to unattended liability.
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