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النتائج 641 - 650 من 4,936
Hepatotoxicity and reproductive disruption in male lizards (Eremias argus) exposed to glufosinate-ammonium contaminated soil النص الكامل
2019
Zhang, Luyao | Diao, Jinling | Chen, Li | Wang, Zikang | Zhang, Wenjun | Li, Yao | Tian, Zhongnan | Zhou, Zhiqiang
Glufosinate-ammonium (GLA) is a spectrum herbicide that is widely used in agriculture. The toxic effects of GLA on plants and mammals have been extensively studied; however, little is known about its effects on reptiles. In this study, male lizards (Eremias argus) were exposed to GLA contaminated soil for 60 days. Physical conditions, organ coefficients, antioxidant enzyme activity, tissue distribution, histopathological damage, steroid hormones levels, and related gene expression of sex steroids were evaluated. In contrast to unexposed control lizards, the body mass index of the GLA group was decreased, which elucidated that GLA adversely affected the physical condition of E. argus. Changes in antioxidant enzyme activities in response to elevated malondialdehyde levels in lizard testis indicated that testes were strongly affected by oxidative damage, and the increased testis index was associated with severe testis lesions. Moreover, alterations of plasma sex hormone levels and related gene expression levels of sex steroids were also observed, and the mechanism underlying the induction of reproductive toxicity was clarified. The activity of glutamine synthetase was severely inhibited in the liver of the GLA exposure group. Based on the results of liver index and histopathology examinations, the hepatotoxicity effect of GLA was confirmed.
اظهر المزيد [+] اقل [-]Effects of ingested polystyrene microplastics on brine shrimp, Artemia parthenogenetica النص الكامل
2019
Wang, Ying | Zhang, Dian | Zhang, Mingxing | Mu, Jingli | Ding, Guanghui | Mao, Zheng | Cao, Yifei | Jin, Fei | Cong, Yi | Wang, Lijun | Zhang, Weiwei | Wang, Juying
Microplastics are a contaminant of emerging concern which enter the marine environment from a variety of sources. The ingestion and toxic effects of microplastics on marine life, especially for filter feeders, are a cause of concern in view of their ubiquitous nature and their similar size as food sources. To assess the toxic effects of microspheres ingested by brine shrimp larvae, we exposed Artemia parthenogenetica to 10 μm polystyrene microspheres at different concentrations. These concentrations were approximate to the extrapolated marine aquatic environmentally relevant concentrations. The lowest polystyrene concentrations at which ingestion was visualized in A. parthenogenetica were 12 ± 0.57 particles/mL (6.7 ± 0.32 μg/L) and 1.1 ± 0.16 particles/mL (0.61 ± 0.088 μg/L), respectively. There were no significant impacts on the survival, growth or development in A. parthenogenetica occurring over the 14-d exposure across a range of polystyrene nominal concentrations (1–1000 particles/mL or 0.55–550 μg/L). However, abnormal ultrastructures of intestinal epithelial cells were observed upon exposure to polystyrene microspheres, including fewer and disordered microvilli, an increased number of mitochondrion and the appearance of autophagosome. These phenomena could affect nutrition absorption and energy metabolism. Although no major acute or chronic toxicity effects on A. parthenogenetica were observed over 24-h or 14-d exposures, this study provides evidence that the ingestion of polystyrene microplastics at extrapolated environmentally relevant concentrations can be visualized through a microscope to be causing a series of responses in intestinal epithelial cells.
اظهر المزيد [+] اقل [-]Persistence and migration of tetracycline, sulfonamide, fluoroquinolone, and macrolide antibiotics in streams using a simulated hydrodynamic system النص الكامل
2019
Liu, Xiaowei | Lv, Kai | Deng, Chengxun | Yu, Zhimin | Shi, Jianghong | Johnson, Andrew C.
The potential persistence and migration of 14 antibiotics comprising sulfonamides, fluoroquinolones, macrolides and tetracyclines were conducted using a 50-d recirculating flume study supported by batch attenuation experiments with spiked concentrations. The study demonstrated that photodegradation was the dominant attenuation process for these antibiotics in the water environment. The half-lives of 2–26 d were in order of sulfadiazine > sulfadimethoxine > sulfamerazine > sulfamethoxazole > sulfamethazine > sulfathiazole > ofloxacin > enrofloxacin > norfloxacin > ciprofloxacin > erythromycin > tetracycline > roxithromycin > oxytetracycline. These modest half-lives meant that the antibiotics were predicted to travel 30–400 km down a typical river before half the concentration would be lost. All antibiotics were detected on the surface sediment in the flume study. Under hyporheic exchange, some of them continually migrated into the deeper sediment and also the sediment pore water. All fluoroquinolones were detected in the sediments. The sulfonamides were detected in the pore water with relatively high concentrations and frequencies. Sulfadiazine, sulfamethazine and sulfathiazole in the upper layer pore water were found to be approaching equilibrium with the surface water. The high presence of sulfonamides in the pore water indicated that their high mobility and persistence potentially pose a risk to hyporheic zone.
اظهر المزيد [+] اقل [-]Long-term effects of an early-life exposure of fathead minnows to sediments containing bitumen. Part I: Survival, deformities, and growth النص الكامل
2019
Vignet, C. | Frank, R.A. | Yang, Zhunhe | Wang, Z. | Shires, K. | Bree, M. | Sullivan, C. | Norwood, W.P. | Hewitt, L.M. | McMaster, M.E. | Parrott, J.L.
The aim of this study was to investigate the long-term effects of a short exposure to natural sediments within the Athabasca oil sand formation to critical stages of embryo-larval development in fathead minnows (Pimephales promelas). Three different sediments were used: Ref sediment from the upper Steepbank River tested at 3 g/L (containing 12.2 ng/g ∑PAHs), and two bitumen-rich sediments tested at 1 and 3 g/L; one from the Ells River (Ells downstream, 6480 ng/g ∑PAHs) and one from the Steepbank River (Stp downstream, 4660 ng/g ∑PAHs). Eggs and larvae were exposed to sediments for 21 days, then transferred to clean water for a 5-month grow-out and recovery period. Larval fish had significantly decreased survival after exposure to 3 g/L sediment from Stp downstream, and decreased growth (length and weight at 16 days post hatch) in Ells and Stp downstream sediments at both 1 and 3 g/L. Decreased tail length was a sensitive endpoint in larval fish exposed to Ells and Stp downstream sediments for 21 days compared to Ref sediment. After the grow-out in clean water, all growth effects from the bitumen-containing sediments recovered, but adult fish from Stp downstream 3 g/L sediment had significant increases in jaw deformities. The study shows the potential for fish to recover from the decreased growth effects caused by sediments containing oil sands-related compounds, but that some effects of the early-life sediment exposure occur later on in adult fish.
اظهر المزيد [+] اقل [-]Occurrence and distribution of phthalate esters in freshwater aquaculture fish ponds in Pearl River Delta, China النص الكامل
2019
Cheng, Zhang | Liu, Jun-Bo | Gao, Meng | Shi, Guang-Ze | Fu, Xiao-Jiao | Cai, Peng | Lv, Yan-Feng | Guo, Zhong-Bao | Shan, Chun-Qiao | Yang, Zhan-Biao | Xu, Xiao-Xun | Xian, Jun-Ren | Yang, Yuan-Xiang | Li, Kai-Bin | Nie, Xiang-Ping
The concentrations, congener profiles and spatial distribution of 13 phthalate esters (PAEs) in the freshwater fish ponds in the Pearl River Delta (PRD) region were investigated in water and sediment samples collect from 22 sites during Jul. 2016–Sept. 2017. The di-2-ethylhexyl phthalate (DEHP) was the predominant compounds in both water and sediment samples, accounting for 70.1% and 66.1% of ∑PAEs, respectively. The DEHP concentrations in the water samples collected from the sites of Zhongshan (35.7 μg/L), Jingmen (17.3 μg/L) and Nanhai (14.2 μg/L) were higher than that collected from other sampling sites (p <0.05), and exceed the Chinese environmental quality standards for surface water (DEHP, 8.00 μg/L). The concentrations of ΣPAEs (mean and median were 11.8 mg/kg dw and 7.95 mg/kg dw) in sediment was higher than that in sediment of river and estuary in the PRD region (p <0.05). The median concentrations of DEHP and di-n-butyl phthalate (DBP) exceeded recommend environmental risk limit (ERL) that posed a potential risk to the aquaculture fish pond environment in the PRD.
اظهر المزيد [+] اقل [-]Evaluating the utility of elemental measurements obtained from factory-calibrated field-portable X-Ray fluorescence units for aquatic sediments النص الكامل
2019
Dunnington, Dewey W. | Spooner, Ian S. | Mallory, Mark L. | White, Chris E. | Gagnon, Graham A.
We assessed factory-calibrated field-portable X-ray fluorescence (pXRF) data quality for use with minimally-prepared aquatic sediments, including the precision of replicate pXRF measurements, accuracy of factory-calibrated pXRF values as compared to total digestion/ICP-OES concentrations, and comparability of calibrated pXRF values to extractable concentrations. Data quality levels for precision, accuracy, and comparability were not equivalent for element/analyzer combinations. All analyses of elements that were assessed for precision and accuracy on a single analyzer were both precise (<10% relative standard deviation) and accurate (r2 > 0.85) for K, Ca, Ti, Mn, Fe, and Zn. Calibrated pXRF values for Al, K, Ca, Ti, Mn, Fe, Cu, Zn, and Pb were within ∼10% relative difference of total digestion/ICP-OES concentrations. Calibrated pXRF values for Fe, Cu, Zn, As, and Pb were within ∼20% relative difference of extractable concentrations. Some elements had a higher level of data quality using specific analyzers, but in general, no pXRF analyzer had the highest level of data quality in all categories. Collectively, our data indicate that a wide range of factory-calibrated pXRF units are capable of providing high-quality total concentrations for the analysis of aquatic sediments.
اظهر المزيد [+] اقل [-]Mining waste as a cause of increased bioaccumulation of highly toxic metals in liver and gills of Vardar chub (Squalius vardarensis Karaman, 1928) النص الكامل
2019
Dragun, Zrinka | Tepić, Nataša | Ramani, Sheriban | Krasnići, Nesrete | Filipović Marijić, Vlatka | Valić, Damir | Kapetanović, Damir | Erk, Marijana | Rebok, Katerina | Kostov, Vasil | Jordanova, Maja
Freshwater contamination with mining waste can result with high concentrations of toxic metals in the water and in fish organs. In North-Eastern Macedonia, several rivers (e.g., Zletovska, Kriva) are exposed to acid mine drainage from active Pb/Zn mines. Previous studies confirmed high concentrations of dissolved metals in their water. This study was performed in liver and gills of Vardar chub (Squalius vardarensis Karaman, 1928) from three Macedonian rivers (Bregalnica, Kriva and Zletovska) in spring and autumn 2012. The aim was to establish if increased exposure to certain metals have resulted with their increased bioaccumulation. The concentrations of 19 elements were measured in cytosolic tissue fractions, to obtain information on metabolically available metal species. The following ranges of cytosolic concentrations of highly toxic elements were measured in the Vardar chub liver (in μg/L): Cd, 1.18–184; Cs, 0.25–25.4; Tl, 0.02–5.80; Pb, 0.70–61.1. Their ranges measured in the gills (in μg/L) were the following: Cd, 0.24–59.2; Cs, 0.39–24.4; Tl, 0.01–1.00; Pb, 0.65–87.2. Although the water of the mining impacted Zletovska River was highly contaminated with several essential metals, especially with Mn and Zn, the majority of essential elements (Na, K, Ca, Mg, Co, Cu, Fe, Mn, Mo, and Zn) did not reflect the exposure level. In contrast, seven nonessential elements reflected the level of exposure in the water. Significantly increased hepatic and gill concentrations of Cs, Rb, Sr, and Tl were detected in Vardar chub from the Zletovska River compared to the other two rivers, of Cd and Pb in the Zletovska and Kriva River compared to Bregalnica, and of V in the Bregalnica River compared to Zletovska and Kriva rivers. Observed significant metal bioaccumulation, in particular of highly toxic elements, as a consequence of exposure to water contaminated with mining waste points to necessity of intensified supervision of mining impacted rivers.
اظهر المزيد [+] اقل [-]Potentially toxic elements in solid waste streams: Fate and management approaches النص الكامل
2019
Xiong, Xinni | Liu, Xueming | Yu, Iris K.M. | Wang, Lei | Zhou, Jin | Sun, Xin | Rinklebe, Jörg | Shaheen, Sabry M. | Ok, Yong Sik | Lin, Zhang | Tsang, Daniel C.W.
Solid wastes containing potentially toxic elements (PTEs) are widely generated around the globe. Critical concerns have been raised over their impacts on human health and the environment, especially for the exposure to PTEs during the transfer and disposal of the wastes. It is important to devise highly-efficient and cost-effective treatment technologies for the removal or immobilisation of PTEs in solid wastes. However, there is an inadequate overview of the global flow of PTEs-contaminated solid wastes in terms of geographical distribution patterns, which is vital information for decision making in sustainable waste management. Moreover, in view of the scarcity of resources and the call for a circular economy, there is a pressing need to recover materials (e.g., precious metals and rare earth elements) from waste streams and this is a more sustainable and environmentally friendly practice compared with ore mining. Therefore, this article aims to give a thorough overview to the global flow of PTEs and the recovery of waste materials. This review first summarises PTEs content in various types of solid wastes; then, toxic metal(loid)s, radioactive elements, and rare earth elements are critically reviewed, with respect to their patterns of transport transformation and risks in the changing environment. Different treatments for the management of these contaminated solid wastes are discussed. Based on an improved understanding of the dynamics of metal(loid) fates and a review of existing management options, new scientific insights are provided for future research in the development of high-performance and sustainable treatment technologies for PTEs in solid wastes.
اظهر المزيد [+] اقل [-]On-site assessments on variations of PM2.5, PM10, CO2 and TVOC concentrations in naturally ventilated underground parking garages with traffic volume النص الكامل
2019
Liu, Zhijian | Yin, Hang | Ma, Shengyuan | Jin, Gaungya | Gao, Jun | Ding, Wenjun
There have been an increasing number of automobile vehicles in cities, so that newly developed residential areas are mostly designed with underground parking garages (UPGs). For naturally ventilated UPGs, the ventilation performance may be insufficient to discharge totally vehicle-induced pollutants out of the enclosed underground spaces, which consequently results in threats to residents' health. This study, therefore, aims at examining the patterns of pollutant concentrations in naturally ventilation UPGs as well as their sensitivities to traffic volume. In particular, the naturally ventilated UPGs’ weekday particulate matters (PM₂.₅ and PM₁₀), CO₂ and TVOC concentration as well as their relationships between traffic volume were quantitively evaluated based on field measurements in eight residential areas in Baoding, China. Results indicated that daily average PM₂.₅, PM₁₀, CO₂ and TVOC concentrations in studied UPGs were 105.81 μg/m³, 464.17 μg/m³, 571 ppm and 24 ppb, respectively. The PM₂.₅ concentrations in UPGs were slightly higher than that in ambient environments, while the PM₁₀ concentrations in UPGs were significantly higher. Furthermore, both PM₁₀ and TVOC concentrations in UPGs were in significant relationships with traffic volume at the p < 0.01 level, while the concentration of UPG PM₂.₅ generally exhibited a significant correlation (p < 0.01) with that of the ambient. Nevertheless, a combination of traffic volume, the ambient and accumulative effect was much better to explain the hourly PM₁₀ concentration in UPGs. These findings will be conducive to instruct engineers with fundamental knowledge of UPG ventilation design.
اظهر المزيد [+] اقل [-]Zooremediation of leachates from municipal waste using Eisenia fetida (SAV.) النص الكامل
2019
Jóźwiak, Małgorzata Anna | Jóźwiak, Marek | Kozłowski, Rafał | Żelezik, Monika
Leachates from municipal landfills are formed as infiltration waters flowing through the landfill. They contain toxic, dissolved products of biochemical reactions taking place in the deposit. They cause soil and groundwater pollution. It is necessary to take them out of the landfill cover and utilize toxins contained therein, in particular heavy metals. Such processes are conducted with the use of microorganisms. Due to the content of toxic compounds, introducing leachates into the process of biological purification poses a threat to the microorganisms used in these processes.An alternative to microbial co-treatment of sludge and leachate as well as soil contaminated with communal leachate is to use red hybrid of California (Eisenia fetida Sav.), an earthworm resistant to environmental toxins, in particular heavy metals.The aim of the conducted research is to demonstrate the possibility of using red hybrid of California in leachate bioutilization as a complementary or alternative method to the process of leachate utilization with the use of microorganisms.The obtained results led to the conclusion that Eisenia fetida accumulates environmental toxins well. By collecting and processing them in the tissues, it remedies the substrate and retains long life and fertility, and the ability to reproduce. The research demonstrated high dynamics of population growth (from 25 individuals in the initial deposit to 298 individuals after six months of research). These properties are related to the presence of enzyme proteins from the metallothionein group in the gastrointestinal tract cells. Packing heavy metals found in leachates into the metallothionein coat limits their toxic effect on earthworm tissues, which confirms the possibility of using earthworms in the processes of detoxification of municipal leachate.
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