Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 152.797
Filtrar
1.
Environ Monit Assess ; 193(5): 244, 2021 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-33821354

RESUMEN

Polybrominated diphenyl ethers (PBDEs) have been classified as persistent organic pollutants (POPs) as well as endocrine-disrupting compounds (EDCs). This study determined the concentrations of six PBDE congeners (BDE 47, BDE 99, BDE 100, BDE 153, BDE 154, and BDE 183) in water and sediment samples from open city drains, in the Makurdi Metropolitan Area, North Central Nigeria, using gas chromatogragh-mass spectrometer. These congeners are components of the penta- and octa-BDE formulations that have been banned by the European Union. The samples were collected from the drains, bi-monthly, for 1 year across dry and wet seasons. All the congeners considered were found to be present in both water and sediment. The levels of Σ6PBDEs in water ranged from 0.05 to 0.28 ng L-1 during dry season and 0.02 to 0.36 ng L-1 during wet season, while their levels in sediment during dry and wet seasons ranged from 3.22 to 26.26 ng g-1 and 7.51 to 27.41 ng g-1, respectively. The percentage recoveries from solid phase and Soxhlet extractions ranged from 69 to 104% and 70 to 112%, respectively. It was concluded that the presence of all the congeners in both water and sediment posed a pollution risk to the river in which the drains discharge and require further monitoring and necessary preventive measures.


Asunto(s)
Éteres Difenilos Halogenados , Contaminantes Químicos del Agua , China , Ciudades , Monitoreo del Ambiente , Sedimentos Geológicos , Éteres Difenilos Halogenados/análisis , Nigeria , Agua , Contaminantes Químicos del Agua/análisis
2.
Int J Pharm Compd ; 25(2): 126-128, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33798112

RESUMEN

Humectants, hygroscopic substances used to minimize water loss and to prevent the drying out of different types of products, are in common use not only in pharmaceuticals but also in foods, cosmetics, etc. The proper selection of a humectant in a pharmaceutical formula depends upon the dosage form, ingredients, physical and chemical characteristics, as well as stability issues. This article discusses the importance of humectants and their applications in pharmaceutics.


Asunto(s)
Excipientes , Higroscópicos , Composición de Medicamentos , Agua
3.
J Adhes Dent ; 23(2): 159-165, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825429

RESUMEN

PURPOSE: To evaluate the effect of inclusion of two dimethyl sulfoxide (DMSO) concentrations in simplified etch-and-rinse adhesives on dentin bonding durability after three years of water storage. MATERIALS AND METHODS: Forty-two caries-free third molars were divided into six experimental groups (n = 7) according to the following factors: 1) adhesive (Adper Single Bond 2 [SB], 3M Oral Care; Prime&Bond 2.1 [PB], Dentsply Sirona); 2) concentration of DMSO (control group: 0.0% DMSO; addition of 0.2% DMSO [0.2] and 2% DMSO [2.0]). After completing restoration, specimens were stored in water (37°C) for 24 h, sectioned into adhesive-dentin sticks (0.8 mm2), tested for microtensile bond strength (µTBS) at 0.5 mm/min, and examined for nanoleakage (NL) using SEM immediately thereafter or after three years of water storage. Data were subjected to a three-way repeated-measures ANOVA and Tukey's test (α = 0.05) for each property evaluated. RESULTS: After three years of water storage, for both adhesives, the incorporation of 2% DMSO maintained the µTBS when compared to immediate µTBS (p > 0.05). In general, SB resulted in a statistically significantly higher mean of µTBS compared to PB, independent of the DMSO concentration after water storage (p < 0.05). Furthermore, the amount of NL was lower and practically limited to the hybrid layer given the concentrations of 0.2% and 2% DMSO for both tested adhesives after three years. CONCLUSION: The incorporation of DMSO in simplified etch-and-rinse adhesives maintains the long-term stability of the dentin bond.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Dentina , Dimetilsulfóxido , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción , Agua
4.
Ecotoxicol Environ Saf ; 214: 112098, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33662787

RESUMEN

The Deepwater Horizon blowout resulted in the second-largest quantity of chemical dispersants used as a countermeasure for an open water oil spill in the Gulf of Mexico. Of which, the efficacy of dispersant as a mitigation strategy and its toxic effects on aquatic fauna remains controversial. To enhance our understanding of potential sub-lethal effects of exposure to chemically dispersed-oil, sub-adult red drum (Sciaenops ocellatus) were continuously exposed to a Corexit 9500: DWH crude oil chemically enhanced water accommodated fraction (CEWAF) for 3-days and transcriptomic responses were assessed in the liver. Differential expressed gene (DEG) analysis demonstrated that 63 genes were significantly impacted in the CEWAF exposed fish. Of these, 37 were upregulated and 26 downregulated. The upregulated genes were primarily involved in metabolism and oxidative stress, whereas several immune genes were downregulated. Quantitative real-time RT-PCR further confirmed upregulation of cytochrome P450 and glutathione S-transferase, along with downregulation of fucolectin 2 and chemokine C-C motif ligand 20. Ingenuity Pathway Analysis (IPA) predicted 120 pathways significantly altered in the CEWAF exposed red drum. The aryl hydrocarbon receptor pathway was significantly activated, while pathways associated with immune and cellular homeostasis were primarily suppressed. The results of this study indicate that CEWAF exposure significantly affects gene expression and alters signaling of biological pathways important in detoxification, immunity, and normal cellular physiology, which can have potential consequences on organismal fitness.


Asunto(s)
Perciformes/fisiología , Contaminación por Petróleo , Petróleo/toxicidad , Transcriptoma/fisiología , Contaminantes Químicos del Agua/toxicidad , Animales , Peces , Perfilación de la Expresión Génica , Golfo de México , Lípidos , Hígado/química , Contaminación por Petróleo/análisis , Agua/análisis
5.
Nat Commun ; 12(1): 1673, 2021 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-33723263

RESUMEN

There are increasing efforts to engineer functional compartments that mimic cellular behaviours from the bottom-up. One behaviour that is receiving particular attention is motility, due to its biotechnological potential and ubiquity in living systems. Many existing platforms make use of the Marangoni effect to achieve motion in water/oil (w/o) droplet systems. However, most of these systems are unsuitable for biological applications due to biocompatibility issues caused by the presence of oil phases. Here we report a biocompatible all aqueous (w/w) PEG/dextran Pickering-like emulsion system consisting of liposome-stabilised cell-sized droplets, where the stability can be easily tuned by adjusting liposome composition and concentration. We demonstrate that the compartments are capable of negative chemotaxis: these droplets can respond to a PEG/dextran polymer gradient through directional motion down to the gradient. The biocompatibility, motility and partitioning abilities of this droplet system offers new directions to pursue research in motion-related biological processes.


Asunto(s)
Liposomas/química , Quimiotaxis , Dextranos/química , Emulsiones , Movimiento (Física) , Tamaño de la Partícula , Polietilenglicoles/química , Agua
6.
Environ Monit Assess ; 193(4): 235, 2021 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-33779861

RESUMEN

The Okobaba area of the Lagos Lagoon, Nigeria, is characterised by sawmilling activities which are potential threats to resident aquatic organisms. This study was aimed at evaluating the effect of sawmilling activities on the environmental quality of the Lagos lagoon at Okobaba area, Lagos, Nigeria. Surface water, sediment, macrobenthic invertebrates, and fish species were sampled monthly from six stations for 3 months (July-September 2018). Relevant stakeholders were administered a cross-sectional questionnaire to determine their knowledge of the environmental effects of their activities. Environmental samples were analysed following standard methods. Descriptive and inferential statistics were performed using SPSS 20.0 and PAST 1.97. Results showed that surface water dissolved oxygen and chemical oxygen demand were significantly lower, while sediment total organic matter and nitrates were significantly higher at the test site compared to the reference site. A total of 389 macrobenthic invertebrates comprising eight species and two macrobenthic invertebrates comprising one species as well as 121 fishes comprising nine species and 70 fishes comprising nine (9) species were recorded at the reference and test sites respectively. About 46.3% of respondents alluded to improper waste disposal as the major cause of pollution at the test site among others, 66.7% responded that wastes were disposed of by burning among other disposal methods, and 66.6% agreed that the sawmilling activities contributed to reduction of aquatic animal population. We recommend urgent regulatory intervention to address the indiscriminate discharge of wastes and facilitate adequate environmental risk advocacy to sustain life below water (United Nations Sustainable Development Goal 14).


Asunto(s)
Sedimentos Geológicos , Contaminantes Químicos del Agua , Animales , Estudios Transversales , Monitoreo del Ambiente , Peces , Invertebrados , Nigeria , Agua , Contaminantes Químicos del Agua/análisis
7.
Huan Jing Ke Xue ; 42(4): 1714-1723, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742807

RESUMEN

In order to clarify the pollution levels of heavy metals in the drinking water sources of the Lijiang River Basin, surface water samples were collected from 62 sites throughout the Lijiang River during May 2019. Heavy metals, including As, Cd, Cr, Mn, Cu, Zn, Hg, Co, and Sb, in the water samples were analysed. Health risk assessments associated with these nine heavy metals were conducted using the health risk assessment model from the US EPA. The results indicated that the order of the average concentrations of heavy metals in the water samples were Mn > Zn > As > Cr > Cu > Sb > Co > Cd > Hg. No heavy metals exceeded the limit values of the drinking water health standards in China (GB 5749-2006), and the concentrations were lower than the limitations of Grade Ⅰ level in the environmental quality standards for surface water (GB 3838-2002). According to the spatial distribution, the high contents areas of As, Cr, Zn, and Sb were predominantly distributed downstream of the Lijiang River, while the high contents areas of Cd, Cu, Hg, Co, and Mn were mostly distributed in the upper reaches. Multivariate analysis indicated that Cd, Mn, Cu, and Co were primarily from agricultural production; Cr, Zn, and Sb were mainly from tourism transportation; As was predominantly from the weathering of rock parent material and soil erosion; Hg was mainly from the improper disposal of domestic garbage and atmospheric deposition. The results of the health risk assessment indicated that children were more susceptible to the threat of heavy metal pollution than adults, and the average annual risk of carcinogenic heavy metals to human health through drinking water ingestion were higher than those of non-carcinogenic metals. The maximum personal average annual health risk of Cr was higher than the maximum allowance levels recommended by the International Commission on Radiological Protection (5×10-5 a-1). The average annual risk of non-carcinogenic heavy metals (10-14-10-9 a-1) decreased in the order of Co > Cu > Hg > Zn > Sb > Mn, which were far below the maximum allowance levels recommended by the ICRP.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Adulto , Niño , China , Monitoreo del Ambiente , Humanos , Metales Pesados/análisis , Medición de Riesgo , Agua , Contaminantes Químicos del Agua/análisis
8.
Huan Jing Ke Xue ; 42(4): 1801-1810, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742815

RESUMEN

To explore the pollution characteristics, potential sources, and ecological and health risk of organophosphate eaters (OPEs) in the surface water of Taihu Lake, water samples from 18 surrounding rivers were collected, as well as 11 water samples from Taihu Lake. The concentrations of 13 OPEs in the water were determined using UPLC-MS/MS, and the spatial distribution of the OPEs in surface water of Taihu Lake basin was further analyzed. The results indicate that, in addition to tripropyl phosphate (TPrP), 2-ethylhexyl diphenyl phosphate (EHDPP), and tricresyl phosphate (TCrP), ten OPEs were detected in all the water samples, the total concentration (ΣOPEs) ranged from 152.5 ng·L-1 to 2524 ng·L-1, and the concentration median value was 519.2 ng·L-1. Tri(chloropropyl) phosphate (TCPP) and tri(2-chloroethyl) phosphate (TCEP) were the dominant OPEs, with the concentration ranges of 73.7-1753.9 ng·L-1 (medium value:204.6 ng·L-1) and 43.9-313.5 ng·L-1 (medium value:131.3 ng·L-1), respectively. The ΣOPEs decreased from the northwest region to the southeast, which corresponds to the economic and industrial development. The results of the source identification reveal that the wastewater discharge from electronics and textile enterprises, construction materials, and vehicular and marine traffic emissions may be the principal sources of the OPEs in Taihu Lake. The ecological risk assessment results indicate that only TCPP, tri(dichloropropyl) phosphate (TDCP), and triphenyl phosphate (TPhP) in some sites had a low risk. The health risk assessment reveals that there were no risks based on water intake, but the long-term risk of OPEs to the aquatic ecosystem and surrounding residents still need attention.


Asunto(s)
Retardadores de Llama , Contaminantes Químicos del Agua , China , Cromatografía Liquida , Ecosistema , Monitoreo del Ambiente , Ésteres , Retardadores de Llama/análisis , Lagos , Organofosfatos , Medición de Riesgo , Ríos , Espectrometría de Masas en Tándem , Agua , Contaminantes Químicos del Agua/análisis
9.
Huan Jing Ke Xue ; 42(4): 1811-1819, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742816

RESUMEN

Using solid phase extraction-high performance liquid chromatography tandem mass spectrometry, antibiotics belonging to four classes (i.e. sulfonamides, quinolones, tetracycline, and macrolides) in the surface water of Taihu Lake were monitored monthly for a year. Moreover, the potential ecological risks of antibiotics in Taihu Lake were assessed. During the one-year monitoring, all the eighteen target antibiotics were detected to some extent in the surface water. The detection rates of five sulfonamides (sulfamethoxazole, sulfathiazole, sulfadiazine, sulfadimethazine, and trimethoprim) were higher than 50%. The concentrations of quinolones in the surface water were relatively higher. The average and medium concentrations of ciprofloxacin were 13.0 ng·L-1 and 13.5 ng·L-1, respectively. There were significant differences in the antibiotic pollution during the different months, with the average concentrations of the target antibiotics ranging from 7.3 to 33.5 ng·L-1. The concentration levels were lower from June to October, while higher concentrations were observed from February to May and in November. In the surface water of Taihu Lake, the spatial variations of antibiotics among the 20 sampling sites were not significant, with the average concentrations ranging from 13.0 to 14.3 ng·L-1. During the one-year monitoring, the rates of medium and high risks that the antibiotics posed to algae reached 57.5%. The ecological risks of antibiotics were more severe in April and November, and the quinolones may be the dominant risk factor. This issue should be carefully considered by management authorities.


Asunto(s)
Lagos , Contaminantes Químicos del Agua , Antibacterianos/análisis , China , Monitoreo del Ambiente , Medición de Riesgo , Agua , Contaminantes Químicos del Agua/análisis
10.
Huan Jing Ke Xue ; 42(4): 1861-1869, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742821

RESUMEN

Nitrogen and phosphorus are the leading causes of water eutrophication, and it is challenging to remove nitrogen and phosphorus effectively through a single water remediation method. In this study, an aerobic denitrifying bacterium (AD-19) isolated from eutrophic water was used to construct an immobilized biofilm and combined with Phoslock® to remove nitrogen and phosphorus from the water. The phosphorus control efficiency of Phoslock®, nitrogen removal performance of the denitrifying bacteria, and combined remediation performance for the eutrophic water were studied. The results demonstrated that the removal rate of PO43--P in the simulated eutrophic water reached 95% with a dosing ratio of 80 (mass ratio of Phoslock® to PO43--P), and phosphorus release from sediment was effectively inhibited at the same time. Strain AD-19, which was identified as Pseudomonas sp. Using the 16S rDNA method, had a good heterotrophic nitrification and aerobic denitrification ability, and more than 97% of the nitrogen was removed when NH4+-N or NO3--N was used as the nitrogen source. The feasibility of the combined remediation of the eutrophic water was demonstrated using a lake simulation device. Furthermore, this technique was used to restore a eutrophic pond in a park in Wuhan city. After 16 days of treatment, the water quality indices for nitrogen and phosphorus were improved from worse than Grade Ⅴ to Grade Ⅲ (GB 3838-2002, Ministry of Environmental Protection of China, 2002) and remained stable for more than 270 days, indicating that Phoslock® combined with the immobilized biofilm could quickly and effectively restore eutrophic water as well as maintain the water quality for long periods.


Asunto(s)
Fósforo , Agua , Bacterias , China , Desnitrificación , Nitrificación , Nitrógeno , Fósforo/análisis
11.
Huan Jing Ke Xue ; 42(4): 2089-2100, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742844

RESUMEN

A scientific performance evaluation of the regional water ecological civilization construction and clarifying the obstacle factor are key points to improve the performance of regional water ecological civilization construction theory. This study analyzes the coupling relationship between humans and regional water ecology by applying the thinking logic of "driving force-pressure-state-influence-response-management." The regional water ecological civilization construction performance evaluation index system based on the DPSIRM model was established. Combining the unascertained measurement model and obstacle diagnosis model, the water ecological civilization construction performance of Shizuishan City during the past 10 years was empirically evaluated, and the obstacle factors affecting local construction performance were diagnosed and analyzed. The analytical results reveal the following points:First, the performance of the water ecological civilization construction in Shizuishan City gradually increased annually and revealed three development stages:the site visit and slow improvement (2010-2014), intermediate but fast improvement (2015-2017) and good and fast improvement (2018-2019). Second, each subsystem performance index trend varied, but generally, the fluctuations rose. Third, from 2010 to 2014, the average obstacle degree of the subsystem state, subsystem response, and subsystem pressure reached 58.81%, which became the main obstacles restricting the performance of the local water ecological civilization construction. From 2015 to 2017, the average pressure barrier degree reached 21.73%, which was the most significant obstacle to the construction performance. From 2018 to 2019, the average pressure barrier degree remained the largest obstacle by reaching 24.49%. Lastly, the index barrier of the obstacle degree among the top five factors are primarily distributed in the pressure subsystem. A comprehensive frequency ranking of the obstacles, the irrigation water use coefficient, and the pressure of the water consumption per ten thousand yuan of value-added by industry as a representative subsystem are the key directions to future construction. In this paper, the concepts and methods of the research can provide a theoretical reference for the performance evaluation of regional water ecological civilization construction and its obstacle factor diagnosis analysis.


Asunto(s)
Ecosistema , Agua , China , Ciudades , Civilización , Conservación de los Recursos Naturales , Ecología , Humanos , Industrias
12.
Huan Jing Ke Xue ; 42(2): 663-672, 2021 Feb 08.
Artículo en Chino | MEDLINE | ID: mdl-33742860

RESUMEN

Polyfluoroalkyl substances (PFASs) enter the environment through multi-media diffusion and long-distance migration during the long-term manufacture and use of products containing PFASs. This study analyzed 17 PFASs in surface water samples collected from the Wuliangsuhai watershed in the wet and dry seasons, and investigated the temporal and spatial distribution characteristics, potential sources, and ecological risks of PFASs in the study area. PFASs were detected in all surface water samples at concentrations ranging from 4.00 to 263.45 ng·L-1. The spatial distribution of PFASs was affected by local human activities and showed two main types of characteristics. The first type was associated with Yellow River and canal water, which had relatively low concentrations of PFASs and was dominated by perfluorobutanoic acid (PFBA). The second type was associated with drain and lake water receiving industrial, agricultural, and domestic wastewater from the Hetao irrigation area, which had relatively high levels of PFASs and was dominated by perfluorooctanoic acid (PFOA). The PFAS concentrations in water samples collected during the dry season were higher than those collected in the wet season, being affected by the increased production of short-chain PFASs and seasonal changes in the amount of water from the Yellow River. The results of PFOS/PFOA, PFOA/PFNA, and PFHpA/PFOA indicated that the PFASs in the study area originate from atmospheric deposition and point source pollution. The risk assessment results showed that the current risk level from PFOA and PFOS in the study area is relatively low but their long-term cumulative effects cannot be ignored due to the cumulative characteristics and long-distance migration ability of PFASs.


Asunto(s)
Ácidos Alcanesulfónicos , Fluorocarburos , Contaminantes Químicos del Agua , Ácidos Alcanesulfónicos/análisis , Monitoreo del Ambiente , Fluorocarburos/análisis , Humanos , Ríos , Agua , Contaminantes Químicos del Agua/análisis
13.
Huan Jing Ke Xue ; 42(2): 867-873, 2021 Feb 08.
Artículo en Chino | MEDLINE | ID: mdl-33742881

RESUMEN

Blast furnace slag loaded with sulfide nano zero valent iron (S-nZVI@BFS) was applied to remove oxytetracycline (OTC) from water. S-nZVI@BFS was synthesized via liquid reduction and characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer, Emmett and Teller (BET) theory. The effect of reaction time, initial concentration of OTC, initial pH, and coexisting hexavalent chromium[Cr(Ⅵ)] were investigated. The results show that Fe and S were successfully immobilized on the surface of S-nZVI@BFS, the specific surface area and pore volume of which increased to 141.986 m2·g-1 and 0.388 cm3·g-1, respectively, following the loading of nZVI and sulfurization. The utilization rate of the surface active sites of S-nZVI@BFS was improved with an increase of the initial concentration of OTC; the removal rate increased from 20.12 mg·g-1 to 202.74 mg·g-1 when the initial concentration of OTC was increased from 10 mg·L-1 to 100 mg·L-1. The removal rate decreased with pH, declining from 99.78 mg·g-1 to 41.12 mg·g-1 when pH was increased from 3 to 11 due to the switch from Fendon oxidation to electrostatic adsorption. There was notable competition between OTC and Cr(Ⅵ) meaning that Cr(Ⅵ) can inhibit the removal of OTC, which is dose dependent.


Asunto(s)
Oxitetraciclina , Contaminantes Químicos del Agua , Adsorción , Cromo , Hierro , Sulfuros , Agua , Contaminantes Químicos del Agua/análisis
14.
Huan Jing Ke Xue ; 42(2): 988-995, 2021 Feb 08.
Artículo en Chino | MEDLINE | ID: mdl-33742895

RESUMEN

The rhizosphere priming effect (RPE) caused by carbon inputs from crop rhizodeposits plays a key role in regulating the carbon emission flux and carbon balance of farmland soils. Due to frequent alternations between dry and wet conditions, CO2 and CH4 emissions and the RPE in paddy field ecosystems are significantly different to those of other ecosystems. Therefore, it is of great significance to determine the direction and intensity of the rice RPE under alternations of dry and wet to limit greenhouse gas emissions. In this study, using a 13C-CO2 continuous labeling method combined with a pot-based experiment, the response of rice growth and the RPE under alternating dry and wet and continuous flooding conditions was examined. The results showed that, compared with the continuous flooding treatment, the alternating dry and wet treatments significantly increased aboveground and root biomass and the root-to-root ratio, and also increased soil microbial biomass. Under continuous flooding conditions, fluxes of 13CO2 and 13CH4 increased with rice growth from 10.2 µg·(kg·h)-1 and 2.8 µg·(kg·h)-1 (63 d) to 16.0 µg·(kg·h)-1 and 3.2 µg·(kg·h)-1 (75 d), respectively. During the 12-day drying process, the emissions of 13CO2 and 13CH4 derived from rhizosphere deposited C decreased by 57.5% and 88.1%. Under continuous flooding conditions, the RPE for CO2 and CH4 were positive and increased with the growth of rice. Under the alternating dry and wet treatment, after 12 days of drying, the RPE for CO2 and CH4 was reduced from 0.29 mg·(kg·h)-1 and 12.3 µg·(kg·h)-1 (63 d) to -0.39 mg·(kg·h)-1 and 0.07 µg·(kg·h)-1 (75 d). Thus, alternating wet and dry treatment can effectively promote rice growth and reduce the cumulative emissions of CH4. Therefore, adopting appropriate field water management is of great significance for increasing rice yields and mitigating greenhouse gas emissions.


Asunto(s)
Oryza , Suelo , Agricultura , Dióxido de Carbono/análisis , Ecosistema , Metano , Óxido Nitroso/análisis , Rizosfera , Agua , Abastecimiento de Agua
15.
Huan Jing Ke Xue ; 42(3): 1354-1360, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742932

RESUMEN

Phenol is widely used in the production of insulation and thermal insulation materials, adhesives, perfumes, coatings for food containers, paints, and pharmaceutical production, and is also widely detected in the aquatic environment. Long-term exposure to phenol can elicit adverse effects, such as skin burn, liver and central system damage. Here, phenol concentrations in the water and aquatic products of Poyang Lake were investigated. Human health risks from phenol to adults and adolescents were also assessed based on local population exposure parameters. The exposure concentration range of phenol in the studied water and aquatic products was not detected (ND)-556.26 ng·L-1 and 11.98-255.51 µg·kg-1, respectively. Human health risk based on drinking water in different areas ranged from 3.80×10-7-8.46×10-5. Higher human health risks from drinking water was detected in the southern area of Poyang Lake and at the confluence of the Yangtze River to the north. Health risks caused by different types of aquatic products ranges 2.65×10-5-1.47×10-4. In particular, human health risks from the consumption of yellow catfish and catfish are an order of magnitude higher than for other aquatic products. Probabilistic risk assessment was also conducted through Monte Carlo simulation to analyze the health risk to the population in the Poyang Lake Basin and assess its sensitivity of different exposure parameters. The 95th percentile health risk of drinking water and aquatic product consumption in the Poyang Lake Basin was calculated as being acceptable. Overall, the concentrations of phenol had the greatest impact on the calculated health risk values. This study provides valuable information for phenol risk management in the Poyang Lake basin.


Asunto(s)
Lagos , Fenol , Adolescente , China , Monitoreo del Ambiente , Humanos , Lagos/análisis , Medición de Riesgo , Ríos , Agua
16.
Water Sci Technol ; 83(6): 1286-1299, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33767036

RESUMEN

Storm geysers increasingly occur in sewer systems under climate change and rapid urbanization. Mitigation measures are in great demand to avoid safety problems. In this study, three-dimensional computational fluid dynamics models of single-inlet and multi-inlet systems were established to investigate geysering induced by rapid filling and assess the effectiveness of potential mitigation methods. The modeling results suggest that increasing the capacity of the downstream pipe before the inflow front reaches the chamber can effectively reduce the maximum geyser pressure. The peak pressure can be significantly mitigated when the chamber size is designed with care and the drop height between the upstream and downstream pipes is reduced. A diversion deflector with air vents and an orifice plate at the riser top end can alleviate the maximum pressure by about 65% with about 75% of the entrapped air being released. The peak pressure during the geyser event in the multi-inlet model is less than that of a single-inlet model under the same total inflow condition, but more water can be released.


Asunto(s)
Bahías , Modelos Teóricos , Hidrodinámica , Agua , Movimientos del Agua
17.
Water Sci Technol ; 83(6): 1399-1406, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33767045

RESUMEN

Monitoring of Escherichia coli concentrations in river water (RW) is essential to identify fecal pollution of the river. The objective of this study was to assess the suitability of a novel, simple and high throughput method developed in our laboratory to enumerate E. coli concentrations in RW samples. The method is based on the use of the synthetic substrate specific for the ß-d-glucuronidase (GUS) produced by E. coli. GUS activities and E. coli concentrations were monitored at eight selected sites in rivers running through Sapporo, Japan. Because the fluorescence intensities of the synthetic substrate in the RW samples increased linearly over a 4-h incubation period, we could estimate the GUS activities of the RW samples. The GUS activities were highly correlated with E. coli concentrations at >100 most probable numbers 100 mL-1 with a correlation coefficient of 0.87. The GUS activities of the RW samples collected from all sampling sites fitted well to a single correlation equation, which indicates that it was applicable to the estimation of E. coli concentrations regardless of the sampling sites. This method is simple, rapid, reliable, inexpensive, and high throughput, and is therefore useful for monitoring E. coli in RW.


Asunto(s)
Escherichia coli , Ríos , Monitoreo del Ambiente , Glucuronidasa , Japón , Agua , Microbiología del Agua
18.
Water Sci Technol ; 83(6): 1429-1445, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33767048

RESUMEN

Application of sewage sludge biochar as an adsorbent for pollutant removal has obtained special attention due to their low cost and surface functionality. In this research, sludge-tire composite biochar (STB) was successfully prepared through co-pyrolysis at 300, 500 and 700 °C, respectively. Cadmium (Cd) and tetracycline (TC) were selected as the target pollutant. The results indicated that STB has the highest surface area (49.71 m2/g), more inorganic minerals (Kaolinite) as well as relatively stable physicochemical properties with 10% tire particles (TP) at 700 °C. The adsorption results indicated that the pseudo-second-order equation and Langmuir isotherm model could better describe the adsorption of Cd2+ and TC by STB. The maximum adsorption capacity of Cd2+ and TC was 50.25 mg/g and 90.09 mg/g, respectively. The main mechanism of the adsorption process of STB for Cd mainly involves anion binding adsorption and ion exchange. The main mechanism of the adsorption process of STB for TC mainly involves complexation and cation exchange. The present study could set a scientific foundation for further research on the recycle of sewage sludge and tires.


Asunto(s)
Pirólisis , Contaminantes Químicos del Agua , Adsorción , Cadmio , Carbón Orgánico , Cinética , Aguas del Alcantarillado , Agua
19.
Int J Nanomedicine ; 16: 2045-2058, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33731993

RESUMEN

Background: Carbon dots (CDs) emitting near-infrared fluorescence were recently synthesized from green leaves. However, the Hg2+ detection of CDs was limited because of the insufficient water solubility, low fluorescence and poor stability. Methods: Dual fluorescence emission water-soluble CD (Dual-CD) was prepared through a solvothermal method from holly leaves and low toxic PEI1.8k. PEG was further grafted onto the surface to improve the water solubility and stability. Results: The Dual-CD solution can emit 487 nm and 676 nm fluorescence under single excitation and exhibit high quantum yield of 16.8%. The fluorescence at 678 nm decreased remarkably while the emission at 470 nm was slightly affected by the addition of Hg2+. The ratiometric Hg2+ detection had a wide linear range of 0-100 µM and low detection limit of 14.0 nM. In A549 cells, there was a good linear relation between F487/F676 and the concentration of Hg2+ in the range of 0-60 µM; the detection limit was 477 nM. Furthermore, Dual-CD showed visual fluorescence change under Hg2+. Conclusion: Dual-CD has ratiometric responsiveness to Hg2+ and can be applied for quantitative Hg2+ detection in living cells.


Asunto(s)
Carbono/química , Ilex/química , Mercurio/análisis , Hojas de la Planta/química , Puntos Cuánticos/química , Agua/química , Células A549 , Supervivencia Celular , Humanos , Iones , Fenómenos Ópticos , Espectroscopía de Fotoelectrones , Puntos Cuánticos/ultraestructura , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta
20.
Int J Nanomedicine ; 16: 2203-2217, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33762821

RESUMEN

Background: It is well known that smoking is harmful to health; however, it can also ameliorate anxiety. To date, it is unclear whether any nanoparticles found in cigarette mainstream smoke (CS) contribute to this effect. Aim: The aim of this study was to assess the particle composition of CS to identify novel anti-anxiety components. Methods: Carbon dots (CDs) from CS (CS-CDs) were characterised using high-resolution transmission electron microscopy, Fourier-transform infrared, ultraviolet, fluorescence, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. The anti-anxiety effects of CS-CDs in mouse models were evaluated and confirmed with the elevated plus maze and open-field tests. Results: The quantum yield of CS-CDs was 13.74%, with a composition of C, O, and N. In addition, the surface groups contained O-H, C-H, C=O, C-N, N-H, C-O-C, and COO- bonds. Acute toxicity testing revealed that CS-CDs had low in vitro and in vivo toxicity within a certain concentration range. The results of the elevated plus maze and open-field tests showed that CS-CDs had a significant anti-anxiety effect and a certain sedative effect in mice. The mechanism of these effects may be related to the decrease in glutamate levels and promotion of norepinephrine production in the mouse brain, and the decrease in dopamine in mouse serum due to CS-CDs. Conclusion: CS-CDs may have anti-anxiety and certain sedative effects. This study provides a new perspective for a more comprehensive understanding of the components, properties, and functions of CS. Furthermore, it offers a novel target for the development of smoking cessation treatments, such as nicotine replacement therapy.


Asunto(s)
Conducta Animal , Carbono/química , Fumar Cigarrillos/efectos adversos , Sistema Endocrino/metabolismo , Neurotransmisores/metabolismo , Puntos Cuánticos/química , Agua/química , Hormona Adrenocorticotrópica/sangre , Animales , Ansiedad/sangre , Ansiedad/patología , Encéfalo/metabolismo , Encéfalo/patología , Cromatografía Líquida de Alta Presión , Corticosterona/sangre , Hormona Liberadora de Corticotropina/sangre , Dopamina/sangre , Masculino , Ratones , Ratones Endogámicos ICR , Espectroscopía de Fotoelectrones , Puntos Cuánticos/ultraestructura , Células RAW 264.7 , Espectrometría de Fluorescencia , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Pruebas de Toxicidad Aguda , Difracción de Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...