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Estimating Sulfuryl Fluoride Emissions During Structural Fumigation of Residential Houses Полный текст
2019
Tao, Jing
The California Department of Pesticide Regulation conducted indoor air monitoring to estimate sulfury fluoride (SO₂F₂) emissions that bystanders around fumigated houses were potentially exposed to during structural fumigation of residential houses. Monitoring was conducted for 23 fumigations between September 2014 and March 2015. The SO₂F₂ indoor concentrations were measured from four locations inside the fumigated houses once an hour. The decreases of indoor concentrations are due to gas leakage (treatment period) and aeration (aeration period) from the structure to the outdoor environment. Analysis on the monitoring data showed considerable variability of half loss time (11–60 h) and mass loss (22–81%) during treatment periods. The decline of indoor concentrations followed the first-order kinetics; therefore, the hourly flux (g/m²s) of a treatment period can be calculated using initial SO₂F₂ concentration, treatment period mass loss, and house height. Although the California Aeration Plan requires a minimum 12–24 h of aeration after a treatment, the monitoring data showed that 93 ± 5% of the mass at the end of the treatment periods was emitted through the ducting system within the first 2 h. The average ratio of the loss amount in the first hour to the loss in the second was 6:1. These monitoring results provided the critical input for the computer modeling to estimate bystander exposure during structural fumigations of residential houses.
Показать больше [+] Меньше [-]Air pollution survey across the western Mediterranean Sea: overview on oxygenated volatile hydrocarbons (OVOCs) and other gaseous pollutants Полный текст
2019
Vichi, Francesca | Imperiali, Andrea | Frattoni, Massimiliano | Perilli, Mattia | Benedetti, Paolo | Esposito, Giulio | Cecinato, Angelo
Despite the Mediterranean Sea basin is among the most sensitive areas over the world for climate change and air quality issues, it still remains less studied than the oceanic regions. The domain investigated by the research ship Minerva Uno cruise in Summer 2015 was the Tyrrhenian Sea. An overview on the marine boundary layer (MBL) concentration levels of carbonyl compounds, ozone (O₃), and sulfur dioxide (SO₂) is reported. The north-western Tyrrhenian Sea samples showed a statistically significant difference in acetone and SO₂ concentrations when compared to the south-eastern ones. Acetone and SO₂ values were higher in the southern part of the basin; presumably, a blend of natural (including volcanism) and anthropogenic (shipping) sources caused this difference. The mean acetone concentration reached 5.4 μg/m³; formaldehyde and acetaldehyde means were equal to 1.1 μg/m³ and 0.38 μg/m³, respectively. Maximums of 3.0 μg/m³ for formaldehyde and 1.0 μg/m³ for acetaldehyde were detected along the route from Civitavecchia to Fiumicino. These two compounds were also present at levels above the average in proximity of petrol-refining plants on the coast; in fact, formaldehyde reached 1.56 μg/m³ and 1.60 μg/m³, respectively, near Milazzo and Augusta harbors; meanwhile, acetaldehyde was as high as 0.75 μg/m³ at both sites. The levels of formaldehyde agreed with previously reported measurements over Mediterranean Sea and elsewhere; besides, a day/night trend was observed, confirming the importance of photochemical formation for this pollutant. According to this study, Mediterranean Sea basin, which is a closed sea, was confirmed to suffer a high anthropic pressure impacting with diffuse emissions, while natural contribution to pollution could come from volcanic activity, particularly in the south-eastern Tyrrhenian Sea region.
Показать больше [+] Меньше [-]Technologies applicable to the removal of heavy metals from landfill leachate Полный текст
2019
Carvajal-Flórez, Elizabeth | Santiago-Alonso Cardona-Gallo,
This article presents a review of the main physical, chemical, electrochemical, and biological technologies used for treating heavy metals in the wastewater of industrial processes and in synthetic aqueous solutions which could be applied to leachate from landfills. This paper outlines the generalities, operating principles, and modifications made to the technologies described. It discusses and assesses which of these have better removal rates and higher levels of efficiency in minimizing the heavy metal concentrations contained in leachates, such as mercury, chromium, lead, nickel, and copper among others. The first part of the document presents the so-called conventional technologies, such as chemical, physical, and electrochemical treatment. These have been used to treat different wastewater, especially industrial waste, operating adequately from the technical topic, but with high costs and the secondary products’ production. The second part exposes biological treatments tend to be most widely used due to their versatility, effectiveness, and low cost, when compared with traditional technologies. It is important to note that there is no single treatment and that each of the technologies reviewed has different heavy metal decontamination rates. All technologies search to reduce concentrations of heavy metals to values that are safe for the natural resources where they are discharged or disposed, thereby complying with the regulatory limits regulated in each of the regions.
Показать больше [+] Меньше [-]Selection of Agricultural Straws as Sustained-Release Carbon Source for Denitrification in a Drawer-Type Biological Filter Полный текст
2019
Guan, Xiangxiong | Ji, Guixia | Xu, Suyun | Yun, Yunbo | Liu, Hongbo
The aim of this paper is to select feasible agricultural straws as high-quality sustained-release carbon source and examine the effect of determined agricultural organic waste on improving denitrification efficiency. Five kinds of agricultural straws, i.e., the rice straw, the corn straw, the wheat straw, the broomcorn straw, and the reed straw, were evaluated in a self-designed drawer-type biological filter. Results showed that the contents of C, H, and N in the five straws were 34.0~41.0%, 4.9~5.4%, and 1.1~1.5% respectively. The highest TOC release capacity of the rice straw was 12.4 ± 1.3 mg g⁻¹ and the average TOC release of other waste straws ranged from 6.0 to 9.2 mg g⁻¹. The TN release capacities of all the five straws were at a low level, ranging from 0.2 to 1.4 mg g⁻¹. Preliminary denitrification studies showed that the corn and the rice straw could be used as high-quality carbon sources, achieving a COD removal rate of 47.3~50.2% and a TN removal rate of 21.8~24.8% for wastewater with low C/N ratio. The rice straw and the corn straw founctioned both as favorable solid carbon sources and biofilm carriers; the carbon source quality of the corn straw lixivium is more beneficial to microbial utilization. The drawer-type biological filter has showed a good efficiency of denitrification for nitrogen removal when using agricultural straws as biofilm carriers.
Показать больше [+] Меньше [-]Chitosan and Graphene Oxide Nanocomposites as Coatings for Controlled-Release Fertilizer Полный текст
2019
Li, Tiantian | Gao, Bin | Tong, Zhaohui | Yang, Yuechao | Li, Yuncong
Controlled-release fertilizers (CRFs) are an effective approach in providing essential nutrients for plant growth while minimizing the loss of nutrients in water and air, reducing contamination risks. However, commercial CRFs often release nutrients either too quickly or slowly due to the properties of their coating materials (polymer or sulfur). In this work, a novel CRF technology was developed using chitosan (CS) and graphene oxide (GO) nanocomposites as coating materials. CS and GO solutions were applied at varying ratios in preparing different nanocomposites. CS and GO formed homogeneous nanocomposite films through their interactions with each other. Fertilizer beads were successfully encapsulated by the CS-GO films using the simple dipping method. Resulting CRFs showed controlled-release behaviors, with nutrient release lasting for about a week. Although additional investigations are required for further evaluation and optimization, this method presents a promising concept for an alternative fertilizer-coating technology.
Показать больше [+] Меньше [-]Effectivity–ecosphere–economics in nZEB retrofit procedures Полный текст
2019
Ryńska, Elżbieta | Koźmińska, Urszula | Rucińska, Joanna
Sustainable development has by now become an element deeply integrated in the everyday design. It has many shades and may be found under many names. We speak about resiliency in design and procurement of passive, ecologic, plus energy, or nZEB buildings. Nevertheless, if we look closely, we may distinguish certain characteristic ideas. First, sustainable development of societies and urbanization processes should be consistent on a deeper level than presently, and be included within design processes, organization, and planning, as well as modernization and redevelopment procedures of existing urban tissue. Secondly, urbanization should be perceived holistically, as an interaction and harmonious development of both natural and manmade environments, with solutions based on the best technical and technological standards available. Lastly, described ideas are achievable only, if we include continuous cooperation between urban planners, architects, specialist consultants, as well as energy-efficient interdisciplinary solutions to achieve high standard energy measures. One of the thresholds is economic feasibility; the other is health and well-being of the users which should always be discussed as a priority. This paper—outside a brief theoretical approach to initial procedures in design management—will dwell on transformation and modernization of an existing building belonging to the Warsaw University of Technology, one of the oldest universities in Poland, its founding dating back to the beginning of the twentieth century. In 2015, a Nordic Finance Mechanism grant dedicated to the nZEB technology transfer from Norway to Poland was awarded to a group of researchers from Warsaw University of Technology and NTNU Trondheim. The main aim of the project is implementation of nZEB knowledge in Poland, as well as preparation of two integrated concept designs for public (University) buildings as exemplary case studies which could act as the benchmarks for other public buildings.
Показать больше [+] Меньше [-]Natural Sawdust as Adsorbent for the Eriochrome Black T Dye Removal from Aqueous Solution Полный текст
2019
Akhouairi, Siham | Ouachtak, Hassan | Addi, Abdelaziz Ait | Jada, Amane | Douch, Jamaa
This paper deals with the adsorption of an anionic dye, Eriochrome Black T (EBT), from aqueous solutions onto sawdust, which is a natural, eco-friendly, widespread, and a low-cost bio sorbent. The aim of the work is to append values to the wood industry waste. Thus, sawdust was used as adsorbent in both batch reactor (BR) and fixed bed column (FBC), and various operating parameters influencing the adsorption process were investigated. The kinetic and the equilibrium adsorption results were found to agree with, respectively, the prediction of the pseudo-second-order equation and the Langmuir model. This latter allowed also the determination of the maximum EBT dye adsorbed amount, which was found to be about 40.96 mg EBT per gram of sawdust at pH = 4, corresponding to % dye removal of about 80%. In addition, the influence of various parameters on the dye adsorption, such as the adsorbent dose, the aqueous phase pH, and the initial dye concentration, was also examined. In batch experiments, The EBT adsorbed amount was found to increase either by increasing the amount of sawdust or by decreasing the aqueous phase pH, whereas, in the fixed bed column, the EBT retention was found to increase by decreasing the flow rate of the dye through the column. The overall data indicate that the EBT adsorption is mainly governed by the electrostatic interactions occurring between the adsorbent material and the dye.
Показать больше [+] Меньше [-]Sunflower stalk–derived biochar enhanced thermal activation of persulfate for high efficient oxidation of p-nitrophenol Полный текст
2019
Sun, Peng | Zhang, Kaikai | Gong, Jianyu | Khan, Aimal | Zhang, Yu | Islama, Md Suzaul | Zhang, Yanrong
Sunflower stalk–derived biochars (BC) were prepared at various temperatures (i.e., 500, 650, and 1000 °C) and demonstrated as a highly efficient catalyst in persulfate (PS) activation for the oxidation of p-nitrophenol (PNP) at 60 °C. The apparent PNP oxidation rate constant in the BC500 (0.1543 L mol⁻¹ S⁻¹), BC650 (0.6062 L mol⁻¹ S⁻¹), or BC1000 (2.1379 L mol⁻¹ S⁻¹) containing PS system was about 2, 8 and 28 times higher than that in PS/PNP (0.0751 L mol⁻¹ S⁻¹) system, respectively. The effect of reaction temperature on PNP oxidation was also investigated. Furthermore, the radical quenching tests and electron paramagnetic resonance spectroscopy (EPR) were employed to investigate the sulfate and hydroxyl radicals for PNP oxidation. The Raman results suggested that the defective sites on biochars possess vital role for oxidation of PNP in PS system. The possible activation pathway of PS/BC was proposed that the defective sites on BC were involved for weakening the O–O bond in PS and subsequently cleaving O–O bond by heat to generate sulfate radical. The oxidation of PNP at low concentration (below 100 μg L⁻¹) was completely removed in urban wastewater by PS/BC system within 30 min. This work would provide new insights into PS activation by BC catalyst and afford a promising method for organic pollutant removal in high-temperature wastewater.
Показать больше [+] Меньше [-]Ultra-morphology of the scale as an indicator of the stress of Acid Black-1 (AB-1, CI: 20470) and zinc (Zn) Полный текст
2019
Kaur, Ramandeep | Arawindara Kaura, | Kaur, Kirandeep
High contents of azo dyes and heavy metals enter surface waters with the wastewater from dying and dye-manufacturing industries and pose serious threat to fish. In the present study, changes in the ultra-morphological features of the scale have been evaluated as indicators of the stress of lethal and sublethal concentrations of an azo dye Acid Black-1 (AB-1, CI 20470), zinc (Zn), and their mixture AB-1 + Zn to Labeo rohita. Fish were exposed for 96 h to lethal concentration (LC) causing 0–70% mortality, i.e., LC₀, LC₂₀, LC₅₀, and LC₇₀ of AB-1 (4, 6, 8, and 10 mg/L respectively) and Zn (25, 50, 55, and 60 mg/L respectively) and LC₀, LC₅₀, and LC₇₀ of AB-1 + Zn (2 + 15, 2 + 20, and 2 + 25 mg/L respectively). Subchronic exposures of 150 days were given to 1/12, 1/6, and 1/3 of 96 h LC₅₀ values of AB-1, Zn, and AB-1 + Zn. After each exposure, the fish were kept for a recovery period of 90 days. Breakage of circuli, erosion and breakage of lepidonts, uprooting of tubercles, and disappearance of intercircular teeth were observed in all the fish, after 96 h exposure to AB-1, Zn, and AB-1 + Zn. However, damage to focus and holes were common on the scales of Zn-exposed fish. The mixture AB-1 + Zn was more toxic than either of the two as loss of circuli, lepidonts, and intercircular teeth, and sloughing of surface were observed in the scales after 96 h exposure to 2 + 25 mg/L. Damage at this concentration was more than the damage at 8/10 mg/L AB-1 and 55/60 mg/L Zn. After 150 days of exposure, damage due to sublethal concentrations was more than the damage due to all the concentrations of 96 h exposure. Irregular and sloughed circuli were common at 2 + 1.79 and 2 + 3.59 mg/L AB-1 + Zn. Cracks all over the surface (2 + 7.18 mg/L), calcium projections (2 + 3.59 and 2 + 7.18 mg/L), and holes (2 + 7.18 mg/L) hint towards synergistic toxicity of the mixture. It seems that the present dye and metal formed complexes with collagen and osteoblastic cells of the scale that caused an increase in damage during the post-exposure period. Scales of 2 + 7.18 mg/L AB-1 + Zn exposed fish were completely devoid of the normal architectural pattern on the 90th day of the recovery period. Changes in the ultra-morphology of scales at LC₀ (0% mortality) and sublethal concentrations show that these are early indicators of the stress of minute quantities of dyes and metals in water. This is a first report on the cumulative toxicity of the two most abundant components of textile industry effluents.
Показать больше [+] Меньше [-]How to preserve and handle fish liver samples to conserve RNA integrity Полный текст
2019
Vehniäinen, Eeva-Riikka | Ruusunen, Maiju | Vuorinen, Pekka J. | Keinänen, Marja | Oikari, Aimo O. J. | Kukkonen, Jussi V. K.
How to preserve and handle fish liver samples to conserve RNA integrity Полный текст
2019
Vehniäinen, Eeva-Riikka | Ruusunen, Maiju | Vuorinen, Pekka J. | Keinänen, Marja | Oikari, Aimo O. J. | Kukkonen, Jussi V. K.
As transcriptomic studies are becoming more and more common, it is important to ensure that the RNA used in the analyses is of good quality. The RNA integrity may be compromised by storage temperature or freeze-thaw cycles, but these have not been well studied in poikilothermic fishes. This work studied the effects of tissue storage time and temperature, and freeze-thaw cycles of tissue and extracted RNA on RNA integrity in brown trout (Salmo trutta L.) liver. The storage time and temperature had an effect on RNA integrity, but RNA suitable for quantitative reverse transcription PCR (RT-qPCR) (RIN > 7) was still obtained from samples preserved at − 20 °C for 6 months. Freeze-thaw cycles of tissue or RNA did not compromise the integrity of RNA. RNA degradation had an effect on RT-qPCR results, and the effect depended on gene. The RT-qPCR analysis of historical samples from a bleached kraft pulp mill effluent exposure in 1984 revealed no significant cyp1a induction. Recommendations are given for the preservation and handling procedures of samples designated for transcriptomic analyses.
Показать больше [+] Меньше [-]How to preserve and handle fish liver samples to conserve RNA integrity Полный текст
2019
Vehniäinen, Eeva-Riikka | Ruusunen, Maiju | Vuorinen, Pekka J. | Keinänen, Marja | Oikari, Aimo O.J. | Kukkonen, Jussi V.K. | University of Jyväskylä | http://orcid.org/0000-0001-6061-9014 | 4100110910