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Evaluation of cytotoxic and genotoxic activity of fungicide formulation Tango® Super in bovine lymphocytes Full text
2017
Schwarzbacherová, Viera | Wnuk, Maciej | Lewinska, Anna | Potocki, Leszek | Żebrowski, Jacek | Koziorowski, Marek | Holečková, Beáta | Šiviková, Katarína | Dianovský, Ján
Tango® Super is a two-compound fungicide formulation widely employed in grain protection. However, details of Tango® Super effects on cell cultures have not been fully investigated. In this study, bovine lymphocytes were exposed to a concentration range 0.5; 1.5; 3; 6; and 15 μg mL⁻¹ for 4 h to assess the cytotoxicity and genotoxicity of the fungicide. Our experiments revealed that this fungicide treatment reduced cell viability, decreased cell proliferation and provoked apoptotic cell death. Cell cycle analysis showed predominant accumulation of cells in the G0/G1 phase of the cell cycle. The fungicide was able to induce mitochondrial superoxide production accompanied by elevated levels of carbonylated proteins and changes in the lipid membrane composition. The fungicide did not induce micronuclei production, but stimulated both DNA double-strand breaks and the formation of p53 binding protein, which is accumulated during the DNA repair process at the site of double-strand breaks. Based on the obtained data we suppose that the fungicide-induced DNA damage is the result of oxidative stress, which may contribute to higher occurrence of apoptotic cell death. Because ergosterol biosynthesis-inhibiting fungicides are widely used in agriculture to ensure higher crop yields and may cause health impairment of animals and humans, there is a need for further testing to elucidate their potential genotoxic effects using in vivo and/or in vitro systems.
Show more [+] Less [-]Modelling carbon dioxide emissions from agricultural soils in Canada Full text
2017
Yadav, Dhananjay | Wang, Junye
Agricultural soils are a leading source of atmospheric greenhouse gas (GHG) emissions and are major contributors to global climate change. Carbon dioxide (CO2) makes up 20% of the total GHG emitted from agricultural soil. Therefore, an evaluation of CO2 emissions from agricultural soil is necessary in order to make mitigation strategies for environmental efficiency and economic planning possible. However, quantification of CO2 emissions through experimental methods is constrained due to the large time and labour requirements for analysis. Therefore, a modelling approach is needed to achieve this objective. In this paper, the DeNitrification-DeComposition (DNDC), a process-based model, was modified to predict CO2 emissions for Canada from regional conditions. The modified DNDC model was applied at three experimental sites in the province of Saskatchewan. The results indicate that the simulations of the modified DNDC model are in good agreement with observations. The agricultural management of fertilization and irrigation were evaluated using scenario analysis. The simulated total annual CO2 flux changed on average by ±13% and ±1% following a ±50% variance of the total amount of N applied by fertilising and the total amount of water through irrigation applications, respectively. Therefore, careful management of irrigation and applications of fertiliser can help to reduce CO2 emissions from the agricultural sector.
Show more [+] Less [-]The effects of biodiesels on semivolatile and nonvolatile particulate matter emissions from a light-duty diesel engine Full text
2017
Cheng, Yuan | Li, Shao-Meng | Liggio, John | Hayden, Katherine | Han, Yuemei | Stroud, Craig | Chan, Tak | Poitras, Marie-Josée
Semivolatile organic compounds (SVOCs) represent a dominant category of secondary organic aerosol precursors that are increasingly included in air quality models. In the present study, an experimental system was developed and applied to a light-duty diesel engine to determine the emission factors of particulate SVOCs (pSVOCs) and nonvolatile particulate matter (PM) components at dilution ratios representative of ambient conditions. The engine was tested under three steady-state operation modes, using ultra-low-sulfur diesel (ULSD), three types of pure biodiesels and their blends with ULSD. For ULSD, the contribution of pSVOCs to total particulate organic matter (POM) mass in the engine exhaust ranged between 21 and 85%. Evaporation of pSVOCs from the diesel particles during dilution led to decreases in the hydrogen to carbon ratio of POM and the PM number emission factor of the particles. Substituting biodiesels for ULSD could increase pSVOCs emissions but brought on large reductions in black carbon (BC) emissions. Among the biodiesels tested, tallow/used cooking oil (UCO) biodiesel showed advantages over soybean and canola biodiesels in terms of both pSVOCs and nonvolatile PM emissions. It is noteworthy that PM properties, such as particle size and BC mass fraction, differed substantially between emissions from conventional diesel and biodiesels.
Show more [+] Less [-]Roles of phytoplankton- and macrophyte-derived dissolved organic matter in sulfamethazine adsorption on goethite Full text
2017
Bai, Leilei | Cao, Chicheng | Wang, Chunliu | Wang, Changhui | Zhang, Hui | Jiang, Helong
Phytoplankton-derived dissolved organic matter (PDOM) and macrophyte-derived dissolved organic matter (MDOM) exist ubiquitously in eutrophic freshwater lakes. To understand the heterogeneous roles of individual fluorescent DOM components in the adsorption of antibiotics onto sediment minerals, the adsorptive fractionation of DOM on goethite (α–FeOOH) and its interaction with sulfamethazine (SMT) were investigated using fluorescence excitation-emission matrix combined with parallel factor analysis (EEM–PARAFAC). The affinity sequence for goethite of the 4 fluorescent PARAFAC components followed the order of: tryptophan- > tyrosine- > long emission wavelength (LEW) humic- > and short emission wavelength (SEW) humic-like component. This sequence indicated the preferential adsorption of protein-like substances. Meanwhile, tyrosine-like components can strongly form complexes with SMT with a large binding constant, followed by tryptophan- and SEW humic-like components. However, LEW humic-like component did not effectively react with SMT. The main mechanism of fluorescence quenching between DOM and SMT was static quenching. The result indicated that protein-like substances in DOM were favorable to SMT adsorption by acting as a bridge to form complexes with both goethite surface and SMT molecules, whereas humic-like substances played secondary roles in the DOM–goethite–SMT ternary system. Due to its higher content of protein-like substances, PDOM improved the SMT adsorption on goethite more than MDOM. Therefore, the abundant DOM released from phytoplankton and macrophytes affected the transport of antibiotics to sediments and might eventually change their bioavailability and toxicity to organisms.
Show more [+] Less [-]Mechanistic insight into degradation of endocrine disrupting chemical by hydroxyl radical: An experimental and theoretical approach Full text
2017
Xiao, Ruiyang | Gao, Lingwei | Wei, Zongsu | Spinney, Richard | Luo, Shuang | Wang, Donghong | Dionysiou, Dionysios D. | Tang, Chong–Jian | Yang, Weichun
Advanced oxidation processes (AOPs) based on formation of free radicals at ambient temperature and pressure are effective for treating endocrine disrupting chemicals (EDCs) in waters. In this study, we systematically investigated the degradation kinetics of bisphenol A (BPA), a representative EDC by hydroxyl radical (OH) with a combination of experimental and theoretical approaches. The second–order rate constant (k) of BPA with OH was experimentally determined to be 7.2 ± 0.34 × 109 M−1 s−1 at pH 7.55. We also calculated the thermodynamic and kinetic behaviors for the bimolecular reactions by density functional theory (DFT) using the M05–2X method with 6–311++G** basis set and solvation model based on density (SMD). The results revealed that H–abstraction on the phenol group is the most favorable pathway for OH. The theoretical k value corrected by the Collins–Kimball approach was determined to be 1.03 × 1010 M−1 s−1, which is in reasonable agreement with the experimental observation. These results are of fundamental and practical importance in understanding the chemical interactions between OH and BPA, and aid further AOPs design in treating EDCs during wastewater treatment processes.
Show more [+] Less [-]Endosulfan induces autophagy and endothelial dysfunction via the AMPK/mTOR signaling pathway triggered by oxidative stress Full text
2017
Zhang, Lianshuang | Wei, Jialiu | Ren, Lihua | Zhang, Jin | Wang, Ji | Jing, Li | Yang, Man | Yu, Yang | Sun, Zhiwei | Zhou, Xianqing
Cardiovascular diseases is related to environmental pollution. Endosulfan is an organochlorine pesticide and its toxicity has been reported. However, the relationship between oxidative stress and autophagy induced by endosulfan and its underlying mechanism remain confusing. In this study, human umbilical vein endothelial cells (HUVECs) were chosen to explore the toxicity mechanism and were treated with 0, 1, 6, 12 μg/mL−1 endosulfan for 24 h, respectively. The present results showed that autophagy could be induced by endosulfan, which was verified by the monodansylcadaverine staining, autophagic ultrastructural observation, and LC3-I/LC3-II conversion. In addition, the levels of adenosine triphosphate (ATP), the mitochondria membrane potential (MMP) were significantly decreased in a dose-dependent way. The expression of proinflammatory cytokines (tumor necrosis factor α, interleukin-1β, and interleukin-6) were significantly elevated, and the index of endothelial function such as monocyte chemotactic protein 1 (MCP-1), intercellular cell adhesion molecule-1 (ICAM-1) increased. Moreover, endosulfan had an activation effect on the 5′AMP-activated protein kinase (AMPK)/rapamycin (mTOR) signaling pathway. Our findings demonstrated that endosulfan could induce oxidative stress and mitochondria injury, activate autophagy, induce inflammatory response, and eventually lead to endothelial dysfunction via the AMPK/mTOR pathway. This indicates that exposure to endosulfan is a potential risk factor for cardiovascular diseases.
Show more [+] Less [-]Statistical polarization in greenhouse gas emissions: Theory and evidence Full text
2017
Remuzgo, Lorena | Trueba, Carmen
The current debate on climate change is over whether global warming can be limited in order to lessen its impacts. In this sense, evidence of a decrease in the statistical polarization in greenhouse gas (GHG) emissions could encourage countries to establish a stronger multilateral climate change agreement. Based on the interregional and intraregional components of the multivariate generalised entropy measures (Maasoumi, 1986), Gigliarano and Mosler (2009) proposed to study the statistical polarization concept from a multivariate view. In this paper, we apply this approach to study the evolution of such phenomenon in the global distribution of the main GHGs. The empirical analysis has been carried out for the time period 1990–2011, considering an endogenous grouping of countries (Aghevli and Mehran, 1981; Davies and Shorrocks, 1989). Most of the statistical polarization indices showed a slightly increasing pattern that was similar regardless of the number of groups considered. Finally, some policy implications are commented.
Show more [+] Less [-]National-scale exposure prediction for long-term concentrations of particulate matter and nitrogen dioxide in South Korea Full text
2017
Kim, Sun Young | Song, Insang
The limited spatial coverage of the air pollution data available from regulatory air quality monitoring networks hampers national-scale epidemiological studies of air pollution. The present study aimed to develop a national-scale exposure prediction model for estimating annual average concentrations of PM10 and NO2 at residences in South Korea using regulatory monitoring data for 2010. Using hourly measurements of PM10 and NO2 at 277 regulatory monitoring sites, we calculated the annual average concentrations at each site. We also computed 322 geographic variables in order to represent plausible local and regional pollution sources. Using these data, we developed universal kriging models, including three summary predictors estimated by partial least squares (PLS). The model performance was evaluated with fivefold cross-validation. In sensitivity analyses, we compared our approach with two alternative approaches, which added regional interactions and replaced the PLS predictors with up to ten selected variables. Finally, we predicted the annual average concentrations of PM10 and NO2 at 83,463 centroids of residential census output areas in South Korea to investigate the population exposure to these pollutants and to compare the exposure levels between monitored and unmonitored areas. The means of the annual average concentrations of PM10 and NO2 for 2010, across regulatory monitoring sites in South Korea, were 51.63 μg/m3 (SD = 8.58) and 25.64 ppb (11.05), respectively. The universal kriging exposure prediction models yielded cross-validated R2s of 0.45 and 0.82 for PM10 and NO2, respectively. Compared to our model, the two alternative approaches gave consistent or worse performances. Population exposure levels in unmonitored areas were lower than in monitored areas. This is the first study that focused on developing a national-scale point wise exposure prediction approach in South Korea, which will allow national exposure assessments and epidemiological research to answer policy-related questions and to draw comparisons among different countries.
Show more [+] Less [-]The local impact of a coal-fired power plant on inorganic mercury and methyl-mercury distribution in rice (Oryza sativa L.) Full text
2017
Xu, Xiaohang | Meng, Bo | Zhang, Chao | Feng, Xinbin | Gu, Chunhao | Guo, Jianyang | Bishop, Kevin | Xu, Zhidong | Zhang, Sensen | Qiu, Guangle
Emission from coal-fired power plants is one of the major anthropogenic sources of mercury (Hg) in the environment, because emitted Hg can be quickly deposited nearby the source, attention is paid to the effects of coal-burning facilities on levels of toxic methyl-mercury (MeHg) in biota near such sources. Since rice is an agricultural crop that can bio-accumulate MeHg, the potential effects of a large Hg-emitting coal-fired power plant in Hunan Province, China on both inorganic Hg (Hg(II)) and MeHg distributions in rice was investigated. Relatively high MeHg (up to 3.8 μg kg−1) and Hg(II) (up to 22 μg kg−1) concentrations were observed in rice samples collected adjacent to the plant, suggesting a potential impact of Hg emission from the coal fired power plant on the accumulation of Hg in rice in the area. Concentrations of MeHg in rice were positively correlated with soil MeHg, soil S, and gaseous elemental Hg (GEM) in ambient air. Soil MeHg was the most important factor controlling MeHg concentrations in rice. The methylation of Hg in soils may be controlled by factors such as the chemical speciation of inorganic Hg, soil S, and ambient GEM.
Show more [+] Less [-]Characteristics and source distribution of air pollution in winter in Qingdao, eastern China Full text
2017
Li, Lingyu | Yan, Dongyun | Xu, Shaohui | Huang, Mingli | Wang, Xiaoxia | Xie, Shaodong
To characterize air pollution and determine its source distribution in Qingdao, Shandong Province, we analyzed hourly national air quality monitoring network data of normal pollutants at nine sites from 1 November 2015 to 31 January 2016. The average hourly concentrations of particulate matter <2.5 μm (PM2.5) and <10 μm (PM10), SO2, NO2, 8-h O3, and CO in Qingdao were 83, 129, 39, 41, and 41 μg m⁻³, and 1.243 mg m⁻³, respectively. During the polluted period, 19–26 December 2015, 29 December 2015 to 4 January 2016, and 14–17 January 2016, the mean 24-h PM2.5 concentration was 168 μg m⁻³ with maximum of 311 μg m⁻³. PM2.5 was the main pollutant to contribute to the pollution during the above time. Heavier pollution and higher contributions of secondary formation to PM2.5 concentration were observed in December and January. Pollution pathways and source distribution were investigated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analyses. A cluster from the west, originating in Shanxi, southern Hebei, and west Shandong Provinces, accounted for 44.1% of the total air masses, had a mean PM2.5 concentration of 134.9 μg m⁻³ and 73.9% trajectories polluted. This area contributed the most to PM2.5 and PM10 levels, >160 and 300 μg m⁻³, respectively. In addition, primary crustal aerosols from desert of Inner Mongolia, and coarse and fine marine aerosols from the Yellow Sea contributed to ambient PM. The ambient pollutant concentrations in Qingdao in winter could be attributed to local primary emissions (e.g., coal combustion, vehicular, domestic and industrial emissions), secondary formation, and long distance transmission of emissions.
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