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النتائج 411 - 420 من 6,548
Temporal dynamic of anthropogenic fibers in a tropical river-estuarine system النص الكامل
2020
Strady, Emilie | Kieu-Le, Thuy-Chung | Gasperi, Johnny | Tassin, Bruno
Temporal dynamic of anthropogenic fibers in a tropical river-estuarine system النص الكامل
2020
Strady, Emilie | Kieu-Le, Thuy-Chung | Gasperi, Johnny | Tassin, Bruno
Anthropogenic fibers, gathering synthetic fibers, artificial fibers and natural fibers are ubiquitous in the natural environment. Tremendous concentrations of anthropogenic fibers were previously measured in the tropical Saigon River (Vietnam), i.e. a river impacted by textile and apparel industries. In the present study, we want to examine the role of contrasted seasonal variation (e.g., dry and rainy seasons), via the rainfall and monthly water discharges, and of water's physico-chemical conditions on the concentrations of anthropogenic fibers in the surface water. The one year and half monthly survey evidenced that concentrations of anthropogenic fibers varied from 22 to 251 items L⁻¹ and their variations were not related to rainfall, water discharge or abiotic factors. However, their color and length distribution varied monthly suggesting variations in sources and sinks. Based on the 2017 survey, we estimated an annual emission of anthropogenic fibers from the river to the downstream coastal zone of 115–164 × 10¹² items yr⁻¹.
اظهر المزيد [+] اقل [-]Temporal dynamic of anthropogenic fibers in a tropical river-estuarine system النص الكامل
2020
Strady, Emilie | Kieu-Le, Thuy-Chung | Gasperi, Johnny | Tassin, Bruno | Institut méditerranéen d'océanologie (MIO) ; Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS) | Centre Asiatique de Recherche sur l'Eau (CARE) ; Ho Chi Minh City University of Technology [Vietnam National University, HCM] (HCMUT) ; Vietnam National University, Ho Chi Minh City / Đại học Quốc gia TP. Hồ Chí Minh (VNU-HCM)-Vietnam National University, Ho Chi Minh City / Đại học Quốc gia TP. Hồ Chí Minh (VNU-HCM) | Institut des Géosciences de l’Environnement (IGE) ; Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP) ; Université Grenoble Alpes (UGA) | Ho Chi Minh City University of Technology [Vietnam National University, HCM] (HCMUT) ; Vietnam National University, Ho Chi Minh City / Đại học Quốc gia TP. Hồ Chí Minh (VNU-HCM) | Laboratoire Eau Environnement et Systèmes Urbains (LEESU) ; AgroParisTech-École nationale des ponts et chaussées (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12) | Eau et Environnement (GERS-LEE) ; Université Gustave Eiffel
International audience | Anthropogenic fibers, gathering synthetic fibers, artificial fibers and natural fibers are ubiquitous in the natural environment. Tremendous concentrations of anthropogenic fibers were previously measured in the tropical Saigon River (Vietnam), i.e. a river impacted by textile and apparel industries. In the present study, we want to examine the role of contrasted seasonal variation (e.g., dry and rainy seasons), via the rainfall and monthly water discharges, and of water's physico-chemical conditions on the concentrations of anthropogenic fibers in the surface water. The one year and half monthly survey evidenced that concentrations of anthropogenic fibers varied from 22 to 251 items L-1 and their variations were not related to rainfall, water discharge or abiotic factors. However, their color and length distribution varied monthly suggesting variations in sources and sinks. Based on the 2017 survey, we estimated an annual emission of anthropogenic fibers from the river to the downstream coastal zone of 115e164 × 10 12 items yr-1.
اظهر المزيد [+] اقل [-]Behavior and distribution of polystyrene foams on the shore of Tuul River in Mongolia النص الكامل
2020
Battulga, Batdulam | Kawahigashi, Masayuki | Oyuntsetseg, Bolormaa
Foamed plastic debris in aquatic systems has become one of the emerging global contaminants. In this study, the behavior of polystyrene foam (PSF) and microplastics (MPs) adhered on the PSFs were investigated on the Tuul River shore in Ulaanbaatar, the capital city of Mongolia. The micro-sized (<5 mm) PSF, which was the dominant PSF over 600 pieces in 100 m², have accumulated along the shoreline of Tuul River. Carbonyl index (CI) was calculated to evaluate the surface oxidation of macro-sized (20–100 mm), meso-sized (5–20 mm), and micro-sized PSFs and confirm the relative aging depending on photodegradation. CI ranged from 0.00 to 1.09 in the sampled PSFs, whereby the degraded PSFs with high CI were distributed on the shore of downstream of sewer drainage. Micro-sized PSFs showed a wide range of CI and a relatively high average value of CI as compared to those of meso- and macro-sized PSFs. Most of PSFs aggregated with MPs and the adhered MPs have been ubiquitously detected from the surface of PSFs. Adhered micro-sized plastics explored from the surface of PSFs with various sizes, except for mega-sized (>100 mm) PSF, ranged from 5 to 141 items per piece of PSF fragment. The aggregates of PSFs and MPs were common status of PSFs during their transportation. The present findings, which indicated a high concentration of adhered MPs, raise an environmental concern about the widespread aquatic plastic pollution.
اظهر المزيد [+] اقل [-]Growth and physiological responses of tree seedlings to oil sands non-segregated tailings النص الكامل
2020
Zhang, Wen-Qing | Fleurial, Killian | Sherr, Ira | Vassov, Robert | Zwiazek, Janusz J.
Bitumen recovery from oil sands in northeastern Alberta, Canada produces large volumes of tailings, which are deposited in mining areas that must be reclaimed upon mine closure. A new technology of non-segregated tailings (NST) developed by Canadian Natural Resources Limited (CNRL) was designed to accelerate the process of oil sands fine tailings consolidation. However, effects of these novel tailings on plants used for the reclamation of oil sands mining areas remain to be determined. In the present study, we investigated the effects of NST on seedlings of three species of plants commonly planted in oil sands reclamation sites including paper birch (Betula papyrifera), white spruce (Picea glauca) and green alder (Alnus viridis). In the controlled-environment study, we grew seedlings directly in NST and in the two types of reclamation soils with and without added NST and we measured seedling growth, gas exchange parameters, as well as tissue concentrations of selected elements and foliar chlorophyll. White spruce seedlings suffered from severe mortality when grown directly in NST and their needles contained high concentrations of Na. The growth and physiological processes were also inhibited by NST in green alder and paper birch. However, the addition of top soil and peat mineral soil mix to NST significantly improved the growth of plants, possibly due to a more balanced nutrient uptake. It appears that NST may offer some advantages in terms of site revegetation compared with the traditional oil sands tailings that were used in the past. The results also suggest that, white spruce may be less suitable for planting at reclamation sites containing NST compared with the two studied deciduous tree species.
اظهر المزيد [+] اقل [-]The impact of COVID-19 as a necessary evil on air pollution in India during the lockdown النص الكامل
2020
Shehzad, Khurram | Sarfraz, Muddassar | Shah, Syed Ghulam Meran
The study objective is to contemplate the effectiveness of COVID-19 on the air pollution of Indian territory from January 2020 to April 2020. We have executed data from European Space Agency (ESA) and CPCB online portal for air quality data dissemination. The Sentinel – 5 P satellite images elucidate that the Air quality of Indian territory has been improved significantly during COVID-19. Mumbai and Delhi are one of the most populated cities. These two cities have observed a substantial decrease in Nitrogen Dioxide (40–50%) compared to the same period last year. It suggests that the emergence of COVID-19 has been proved to a necessary evil as being advantageous for mitigating air pollution on Indian territory during the lock-down. The study found a significant decline in Nitrogen Dioxide in reputed states of India, i.e., Delhi and Mumbai. Moreover, a faded track of Nitrogen Dioxide can be seen at the Maritime route in the Indian Ocean. An upsurge in the environmental quality of India will also be beneficial for its neighbor countries, i.e., China, Pakistan, Iran, and Afghanistan.
اظهر المزيد [+] اقل [-]Variations in bacterioplankton communities in aquaculture ponds and the influencing factors during the peak period of culture النص الكامل
2020
Fan, Limin | Hu, Gengdong | Qiu, Liping | Meng, Shunlong | Wu, Wei | Zheng, Yao | Song, Chao | Li, Dandan | Chen, Jiazhang
An increase in nutrient input may disturb the bacterioplankton communities in freshwater aquaculture ponds during the peak period of culture. Water samples were collected from ponds of three cultivated species. After the samples were filtered and total DNA was extracted, Illumina high-throughput sequencing was used to profile the spatiotemporal distributions in bacterioplankton communities, the belt diversity, and the influencing factors during this period of time. The results showed that Proteobacteria, Cyanobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla. Biological differences in cultivated species were the main influencing factors that shaped bacterioplankton communities. Monthly variations and thermal stratification provided little and no contribution to bacterioplankton communities, respectively. CODmn, Chla, and TN were the most appropriate parameters to describe the environmental interpretation of bacterial ordinations, and CODmn was the predominant factor. In addition, the higher similarity between CODmn and Chla, shown by clustering analysis, indicated that the algae-bacteria symbiotic system may have an important role in material circulation in freshwater aquaculture pond water during the peak period of culture. The present study has helped to elucidate the biological characteristics of aquaculture tail water, and enriched the basic data provided by bacterioplankton studies.
اظهر المزيد [+] اقل [-]Thallium exposure at low concentration leads to early damage on multiple organs in children: A case study followed-up for four years النص الكامل
2020
Duan, Weixia | Wang, Yongyi | Li, Zhiqiang | Fu, Guanyan | Mao, Longchun | Song, Yunbo | Qu, Yaping | Ye, Lvsu | Zhou, Qu | Yang, Fucheng | Hu, Zhide | Xu, Shangcheng
Thallium (TI) is one of the most toxic heavy metals and priority pollutant metals. The emerging TI environmental pollution worldwide has posed a great threat to human health. However, based on the World Health Organization (WHO), the risk and severity of adverse health effects of TI in the range of 5–500 μg/L are uncertain. Moreover, evidence regarding the adverse impacts of TI on children’s health is still insufficient. Herein, we aim to investigate the early adverse effects of TI on children’s health and provide references for the WHO to establish stricter safety limits of TI. From 2015 to 2019, urinary TI and many clinical laboratory parameters related to blood routine, hepatic, renal, myocardial, coagulation function and serum electrolyte were measured in six children aged 1–9 years. The urinary TI concentration ranged from 13.4 μg/L to 60.1 μg/L with a mean of 36.1 μg/L and a median of 34.8 μg/L in six children in 2015. Although only four children felt a little poor appetite, several laboratory abnormalities indicated early damage in liver, renal, and myocardial functions in all children in 2015. After treatment and following up for four years, although the children’s TI concentration decreased below 5 μg/L, their liver and renal functions did not completely recover, and their myocardial function worsened. Results indicated that impaired liver, renal, and myocardial functions were closely associated with elevated urinary TI concentration in children. Considering the increasing use of TI in high-technology industries and emerging TI environmental-contamination zones worldwide, establishing stricter safety limits of TI and paying more attention to the adverse health effects of TI on children are urgently required.We found that a relatively low concentration of thallium (13.4 μg/L to 60.1 μg/L) impaired liver, renal, and myocardial function in six children. After treatment and following up these children for four years, although their urinary TI concentration decreased below 5 μg/L, their liver and renal functions did not completely recover, and their myocardial function worsened.
اظهر المزيد [+] اقل [-]Missed atmospheric organic phosphorus emitted by terrestrial plants, part 2: Experiment of volatile phosphorus النص الكامل
2020
Li, Wei | Li, Bengang | Tao, Shu | Ciais, Philippe | Piao, Shilong | Shen, Guofeng | Peng, Shushi | Wang, Rong | Gasser, Thomas | Balkanski, Yves | Li, Laurent | Fu, Bo | Yin, Tianya | Li, Xinyue | An, Jie | Han, Yunman
The emission and deposition of global atmospheric phosphorus (P) have long been considered unbalanced, and primary biogenic aerosol particles (PBAP) and phosphine (PH₃) are considered to be the only atmospheric P sources from the ecosystem. In this work, we found and quantified volatile organic phosphorus (VOP) emissions from plants unaccounted for in previous studies. In a greenhouse in which lemons were cultivated, the atmospheric total phosphorus (TP) concentration of particulate matter (PM) was 41.8% higher than that in a greenhouse containing only soil, and the proportion of organic phosphorus (OP) in TP was doubled. ³¹P nuclear magnetic resonance tests (³¹P-NMR) of PM showed that phosphate monoesters were the main components contributed by plants in both the greenhouse and at an outside observation site. Atmospheric gaseous P was directly measured to be 1–2 orders of magnitude lower than P in PM but appeared to double during plant growing seasons relative to other months. Bag-sampling and gas chromatography mass spectrometry (GCMS) tests showed that the gaseous P emitted by plants in the greenhouse was triethyl phosphate. VOP might be an important component of atmospheric P that has been underestimated in previous studies.
اظهر المزيد [+] اقل [-]Transport and transformation of Cd between biochar and soil under combined dry-wet and freeze-thaw aging النص الكامل
2020
Meng, Zhuowen | Huang, Shuang | Xu, Ting | Deng, Yiyi | Lin, Zhongbing | Wang, Xiugui
We quantified the transport and transformation of Cd in historically contaminated soil (OS) and artificially contaminated soil (NS), treated with 3% (w/w) rice straw biochar prepared at 400 °C (BC400) and 700 °C (BC700) under combined dry-wet and freeze-thaw cycles for 72 days simulating the natural aging process of 8 years. An improved three-layer mesh experiment was developed to simulate the natural situation in field. The result showed that the total Cd concentration increased in the biochar but decreased in the soil, suggesting that Cd was transported from the soil into the biochar during the aging process. The total Cd concentration in BC400 treated with both soils was higher than that in BC700 treated with both soils, however, BC700 displayed stronger ability on immobilizing Cd than BC400 because the Tessier exchangeable Cd fraction in BC700 treated both soils was lower than that in BC400 treated with both soils. The average Tessier exchangeable Cd fraction in the soil and biochar decreased in all treatments during the aging process, indicating that Cd tended to be more stable in the soil for a long term. The result also showed that biochar could immobilizate Cd by decreasing the Tessier exchangeable Cd fraction of soil and biochar, and the quantitative contributions of biochar and soil to Cd immobilization were different in OS and NS treated with BC400 and BC700. The biochar contribution to the reduction in Tessier exchangeable Cd fraction accounted for 40–85% in NS treated with BC400 and 54–82% in NS treated with BC700. However, in OS treated with biochar, the biochar contribution accounted for nearly 100%, and soil had almost no contribution. In summary, OS did not contribute to Cd immobilization, while NS contributed nearly 50% to Cd immobilization, and BC700 was more effective in immobilizing Cd than BC400.
اظهر المزيد [+] اقل [-]A preliminary analysis of microplastics in edible versus non-edible tissues from seafood samples النص الكامل
2020
Akoueson, Fleurine | Sheldon, Lisa M. | Danopoulos, Evangelos | Morris, Steve | Hotten, Jessica | Chapman, Emma | Li, Jiana | Rotchell, Jeanette M.
Plastics have been widely reported to be present in the environment yet there are still many questions regarding the extent of this and the impacts these may have on both the environment and human health. The purpose of this investigation is to determine levels of micro and mesoplastic (MP), in the 1–5000 μm range, in commercially important species of finfish and shellfish. Additionally, to determine and compare the relative MP levels in edible versus non-edible tissues, and consider the wider implications in terms of human health concerns with a preliminary risk identification approach. For several fish species, samples taken from typically non-edible (gills, digestive system) and edible (muscle) flesh, and were analysed separately. Scallops, where all tissues are edible, were analysed whole. Significant differences were observed in the number of particles isolated from the finfish gills and digestive tissues relative to the control samples, but not in the edible flesh. For scallops, the abundance of particles in the Scottish samples did not vary significantly from the control, while the Patagonian scallops displayed significantly higher numbers of MPs. Characterisation of MPs by FTIR microscopy found that 16–60% (depending on species) were polyethylene terephthalate (PET) and polyethylene (PE) in origin. The risk identification results validate MPs as an emerging risk in the food chain and establish seafood as a vector for the exposure and uptake of MPs through the ingestion route for humans. Levels of MPs in seafood, and a direct link to the human food chain, suggests that their quantification be included as one food safety measure.
اظهر المزيد [+] اقل [-]Ecotoxicity of trace elements to chicken GALLUS gallus domesticus exposed to a gradient of polymetallic-polluted sites النص الكامل
2020
Kribi-Boukhris, Sameh EL. | Boughattas, Iteb | Zitouni, Nesrine | Helaoui, Sondes | Sappin-Didier, Valérie | Coriou, Cécile | Bussiere, Sylvie | Banni, Mohamed
Ecotoxicity of trace elements to chicken GALLUS gallus domesticus exposed to a gradient of polymetallic-polluted sites النص الكامل
2020
Kribi-Boukhris, Sameh EL. | Boughattas, Iteb | Zitouni, Nesrine | Helaoui, Sondes | Sappin-Didier, Valérie | Coriou, Cécile | Bussiere, Sylvie | Banni, Mohamed
Mining activity may cause heavy metal accumulation, which threatens human and animal health by their long-term persistence in the environment. This study aims to assess the impact of polymetallic pollution on chicken (Gallus domesticus) from old lead mining sites in northeast of Tunisia: Jebel Ressas (JR). Samples of soil and chickens were collected from five sites being ranked along a gradient of heavy metal contamination. Heavy metal loads were evaluated in soil samples and in chicken liver and kidney. Biochemical evaluation of oxidative stress parameters termed as Catalase (CAT), Glutathione-S-Transferase (GST), and Malondialdehydes (MDA) accumulation was monitored. Metallothionein protein level was assessed as a specific response to heavy metals. DNA alteration was achieved using MNi frequency in the investigated tissues. Finally, the evaluation of gene expression levels of CAT, GST, mt1, mt4, P53, bcl2, caspase3 and DNA-ligase was performed. Our data showed the highest loads of Cd, Cu, Zn and Pb in tissues of animals from site 3, being more pronounced in kidney. Biochemical data suggested a significant increase in antioxidant enzymes activities in all sites respect to control except in site 3 were CAT and GST were inhibited. DNA alteration was observed in all tissues being very pronounced in animals from site 3. Overall, transcriptomic data showed that genes involved in apoptosis were up-regulated in animals exposed to the most contaminated soils. Our data suggest that chicken and selected biomarkers offer a suitable model for biomonitoring assessment of heavy metals transfer through the food web in mining sites. Finally, the obtained results of heavy metals accumulation and related alterations should be carefully considered in view of the controversial relationship between distribution and toxicology of contaminants in exposed organisms.
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