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Результаты 3171-3180 из 4,043
Concentrations, properties, and health risk of PM2.5 in the Tianjin City subway system Полный текст
2016
Wang, Bao-Qing | Liu, Jian-Feng | Ren, Zi-Hui | Chen, Rong-Hui
A campaign was conducted to assess and compare the personal exposure in L3 of Tianjin subway, focusing on PM₂.₅ levels, chemical compositions, morphology analysis, as well as the health risk of heavy metal in PM₂.₅. The results indicated that the average concentration of the PM₂.₅ was 151.43 μg/m³ inside the train of the subway during rush hours. PM₂.₅ concentrations inside car under the ground are higher than those on the ground, and PM₂.₅ concentrations on the platform are higher than those inside car. Regarding metal concentrations, the highest element in PM₂.₅ samples was Fe; the level of which is 17.55 μg/m³. OC is a major component of PM₂.₅ in Tianjin subway. Secondary organic carbon is the formation of gaseous organic pollutants in subway. SEM–EDX and TEM–EDX exhibit the presence of individual particle with a large metal content in the subway samples. For small Fe metal particles, iron oxide can be formed easily. With regard to their sources, Fe-containing particles are generated mainly from mechanical wear and friction processes at the rail–wheel–brake interfaces. The non-carcinogenic risk to metals Cr, Ni, Cu, Zn and Pb, and carcinogenic hazard of Cr and Ni were all below the acceptable level in L3 of Tianjin subway.
Показать больше [+] Меньше [-]Performance analysis and optimization of an advanced pharmaceutical wastewater treatment plant through a visual basic software tool (PWWT.VB) Полный текст
2016
Pal, Parimal | Thakura, Ritwik | Chakrabortty, Sankha
A user-friendly, menu-driven simulation software tool has been developed for the first time to optimize and analyze the system performance of an advanced continuous membrane-integrated pharmaceutical wastewater treatment plant. The software allows pre-analysis and manipulation of input data which helps in optimization and shows the software performance visually on a graphical platform. Moreover, the software helps the user to “visualize” the effects of the operating parameters through its model-predicted output profiles. The software is based on a dynamic mathematical model, developed for a systematically integrated forward osmosis-nanofiltration process for removal of toxic organic compounds from pharmaceutical wastewater. The model-predicted values have been observed to corroborate well with the extensive experimental investigations which were found to be consistent under varying operating conditions like operating pressure, operating flow rate, and draw solute concentration. Low values of the relative error (RE = 0.09) and high values of Willmott-d-index (d wᵢₗₗ = 0.981) reflected a high degree of accuracy and reliability of the software. This software is likely to be a very efficient tool for system design or simulation of an advanced membrane-integrated treatment plant for hazardous wastewater.
Показать больше [+] Меньше [-]Toxic heavy metals in the muscle of roe deer (Capreolus capreolus)—food toxicological significance Полный текст
2016
Lehel, József | Laczay, Péter | Gyurcsó, Adrienn | Jánoska, Ferenc | Majoros, Szilvia | Lányi, Katalin | Marosán, Miklós
The study was performed on 20 (10 males, 10 females) roe deer (Capreolus capreolus) to investigate the concentration of cadmium, lead, mercury, and arsenic in the muscle tissue. They reside in forest and meadow, about 50 km distance from industrial activities and traffic. Samples were taken from the musculus biceps femoris of each deer without external contamination after shooting during the regular hunting season on a hunting area close to Eger in Hungary. The determination of heavy metal contents was carried out by inductively coupled plasma optical emission spectrometry (ICP-OES). The statistical analysis was performed by statistical package for the social sciences (SPSS) version 11.0. The measured residue concentration of cadmium was below the limit of detection in the roe deer meat indicating no health risk for the consumers. The average lead concentration (0.48 ± 0.21 mg/kg wet weight) exceeded the regulated maximum limit, but its calculated weekly intake was below the provisional tolerable weekly intake (PTWI). The residue level of mercury is not regulated and the average mercury content of roe deer meat (0.87 ± 0.40 mg/kg wet weight) was about half of PTWI, but the consumption of meat with the highest detected concentrations results in higher PTWI than recommended. The measured concentration of arsenic (0.27 ± 0.20 mg/kg wet weight) in the roe deer meat may not pose any health risk for the human consumers according to the PTWI set by the World Health Organization.
Показать больше [+] Меньше [-]Heavy metal accumulation in Diplodus annularis, Liza aurata, and Solea vulgaris relevant to their concentration in water and sediment from the southwestern Mediterranean (coast of Sfax) Полный текст
2016
Ben Salem, Zohra | Ayadi, Habib
The concentrations of heavy metals (Cd, Cu, Fe, Pb, Ni, and Zn) were measured in the liver, gills, and muscle of Solea vulgaris, Liza aurata, and Diplodus annularis, collected from the south coast of Sfax (Gabes Gulf, southwestern Mediterranean). The concentrations of heavy metals in water exhibited the following decreasing order (expressed in μg l⁻¹): Fe > Ni > Zn > Cu > Pb > Cd whereas the trend is somewhat different in sediments (mg kg⁻¹ D.W.) Fe > Zn > Pb > Ni > Cu > Cd. The levels of heavy metals varied significantly among fish species and tissues. Heavy metal levels were found generally higher in the liver and gills than the muscle in all species. The liver was the target organ for Cd, Cu, Fe, Ni, and Zn accumulation. Nickel and lead, however, exhibited their highest concentrations in the gills. The three studied fishes showed a difference in metals accumulation decreasing in following order S. vulgaris > D. annularis > L. aurata. Solea vulgaris with the highest TFwₐₜₑᵣ, TFₛₑdᵢₘₑₙₜ, and metal concentrations in tissues would be considered as a potential bio-indicator in the south coast of Sfax for the assessment of environmental pollution status. Comparative studies with Luza zone indicate considerable bioaccumulation of heavy metals (Pb and Zn) in the various tissues of fish samples of the south coast of Sfax.
Показать больше [+] Меньше [-]Pollutant emissions and environmental assessment of ethyl 3-ethoxybutyrate, a potential renewable fuel Полный текст
2016
Storey, John M. E. | Bunce, Michael P. | Clarke, Edwina M. | Edmonds, Jennifer W. | Findlay, Robert H. | Ritchie, Stephen M. C. | Eyers, Laurent | McMurry, Zackery A. | Smoot, James C.
Renewable and bio-based transportation fuel sources can lower the life-cycle greenhouse gas emissions from vehicles. We present an initial assessment of ethyl 3-ethoxybutyrate (EEB) as a biofuel in terms of its performance as a fuel oxygenate and its persistence in the environment. EEB can be produced from ethanol and poly-3-hydroxybutyrate, a bacterial storage polymer that can be produced from non-food biomass and other organic feedstocks. Physicochemical properties of EEB and fuel-relevant properties of EEB-gasoline blends were measured, emissions of criteria pollutants from EEB as a gasoline additive in a production vehicle were evaluated, and fate and persistence of EEB in the environment were estimated. EEB solubility in water was 25.8 g/L, its Kₒw was 1.8, and its Henry’s Law constant was 1.04 × 10⁻⁵ atm-m³/mole. The anti-knock index values for 5 and 20 % v/v EEB-gasoline blends were 91.6 and 91.9, respectively. Reductions in fuel economy were consistent with the level of oxygenation, and criteria emissions were met by the vehicle operated over the urban dynamometer driving cycle (FTP 75). Predicted environmental persistence ranged from 15 to 30 days which indicates that EEB is not likely to be a persistent organic pollutant. In combination, these results suggest a high potential for the use of EEB as a renewable fuel source.
Показать больше [+] Меньше [-]Associations of morbidity and mortality from coronary heart disease with heliogeophysical factors Полный текст
2016
Vaičiulis, Vidmantas | Radišauskas, Ričardas | Ustinavičienė, Rūta | Kalinienė, Gintarė | Tamošiūnas, Abdonas
The aim of this study was to evaluate the associations among morbidity of acute myocardial infarction (AMI) and mortality from ischemic heart disease (IHD) with heliogeophysical factors among the Kaunas population. The study population was stratified into three age categories: 25–54, 55–64, and ≥65 years. In this study, solar flares (SF), solar proton fluences (SPF), and geomagnetic activity (GMA) were employed as heliogeophysical factors and used Poisson regression and two methods of time series modeling (lag and lead). Influence of GMA in different age and sex category is uneven. The mean number of AMI events per day was greatest (23 %) among men aged 25–54 years on the third day and the same sex aged 55–64 years—increased 10 % 2 days before when the GMA intensity was A+S. Both for men and women aged ≥65 years, the highest increase in the mean number of deaths from IHD events per day was observed on the second day when the GMA intensity was A+S—51 and 34 %, respectively. Evaluating the impact of SF of 10⁻⁵ ≤ SF < 10⁻⁴ W/m² (M+X) intensity, the mean number of AMI events per day was greatest for 55–64-year-old women and men on the same and second days. Such SF were associated with a 13 and 20 % increase, respectively. Evaluating the impact of large fluence SPF, it was determined that the increase in the mean number of AMI events per day among 25–54-year-old men was greatest (30 %) 1 day, and death from IHD (54 %) was observed among women aged ≥65 years 2 days before the energy of the SPF has increased.
Показать больше [+] Меньше [-]Distribution of butyltin compounds in Brazil’s southern and southeastern estuarine ecosystems: assessment of spatial scale and compartments Полный текст
2016
dos Santos, Dayana Moscardi | Turra, Alexander | de Marchi, Mary Rosa Rodrigues | Montone, Rosalinda Carmela
Butyltin compounds (BTs), including tributyltin (TBT) and its degradation products, dibutyltin and monobutyltin, have been found in a diversity of aquatic systems and causing toxic effects in target and nontarget organisms. They enter in coastal systems through different sources (as antifouling paints, industrial effluents, etc.) where they interact with biotic and abiotic components, and their distribution is commonly determined by the morphological and hydrodynamic conditions of the coastal systems. In this study, we discuss the contamination by BTs on a spatial scale (eight estuaries with three subareas each) and in different compartments of the estuaries (sediments, suspended particulate matter (SPM), and estuarine catfish tissues (liver and gills). Lower concentrations of BTs were found in the sediments (n.d. to 338 ng g⁻¹) in comparison to studies before a ban of TBT in antifouling paints was enacted, mostly indicating an old input or preservation related with sediment properties and composition. For SPM samples (n.d. to 175 ng L⁻¹) as well as in fish tissues (n.d. to 1426 ng g⁻¹), the presence of these compounds was frequent, especially in the fish due to their movement throughout the estuaries and the potential to assess point sources of BTs. These results indicate that BTs persist in the environment, with variation in amounts between investigated estuaries and even at locations inside the same estuary, because of ideal preservation conditions, transport to remote areas, and input from different sources.
Показать больше [+] Меньше [-]Simultaneous removal of potent cyanotoxins from water using magnetophoretic nanoparticle of polypyrrole: adsorption kinetic and isotherm study Полный текст
2016
Hena, S. | Rozi, R. | Tabassum, S. | Huda, A.
Cyanotoxins, microcystins and cylindrospermopsin, are potent toxins produced by cyanobacteria in potable water supplies. This study investigated the removal of cyanotoxins from aqueous media by magnetophoretic nanoparticle of polypyrrole adsorbent. The adsorption process was pH dependent with maximum adsorption occurring at pH 7 for microcystin-LA, LR, and YR and at pH 9 for microcystin-RR and cylindrospermopsin (CYN). Kinetic studies and adsorption isotherms reflected better fit for pseudo-second-order rate and Langmuir isotherm model, respectively. Thermodynamic calculations showed that the cyanotoxin adsorption process is endothermic and spontaneous in nature. The regenerated adsorbent can be successfully reused without appreciable loss of its original capacity.
Показать больше [+] Меньше [-]Regeneration complexities of Pinus gerardiana in dry temperate forests of Indian Himalaya Полный текст
2016
Kumar, Raj | Shamet, G. S. | Mehta, Harsh | Alam, N. M. | Kaushal, Rajesh | Chaturvedi, O. P. | Sharma, Navneet | Khaki, B. A. | Gupta, Dineśa
Pinus gerardiana is considered an important species in dry temperate forests of North-Western Indian Himalaya because of its influence on ecological processes and economic dependence of local people in the region. But, large numbers of biotic and abiotic factors have affected P. gerardiana in these forests; hence, there is a crucial need to understand the regeneration dynamics of this tree species. The present investigation was conducted in P. gerardiana forests to understand vegetation pattern and regeneration processes on different sites in the region. Statistical analysis was performed to know variability in growing stock and regeneration on sample plots, while correlation coefficients and regression models were developed to find the relationship between regeneration and site factors. The vegetation study showed dominance of P. gerardiana, which is followed by Cedrus deodara, Pinus wallichiana and Quercus ilex in the region. The growing stock of P. gerardiana showed steep increasing and then steadily declining trend from lower to higher diameter class. The distribution of seedling, sapling, pole and trees was not uniform at different sites and less number of plots in each site were observed to have effective conditions for continuous regeneration, but mostly showed extremely limited regeneration. Regeneration success ranging from 8.44 to 15.93 % was recorded in different sites of the region, which suggests that in different sites regeneration success is influenced by collection of cone for extracting seed, grazing/browsing and physico-chemical properties of soil. Regeneration success showed significant correlation and relationship with most of abiotic and biotic factors. The regeneration success is lower than the requirement of sustainable forest, but varies widely among sites in dry temperate forests of Himalaya. More forest surveys are required to understand the conditions necessary for greater success of P. gerardiana in the region.
Показать больше [+] Меньше [-]Valorisation of smooth hound (Mustelus mustelus) waste biomass through recovery of functional, antioxidative and antihypertensive bioactive peptides Полный текст
2016
Sayari, Nadhem | Sila, Assaâd | Haddar, Anissa | Balti, Rafik | Ellouz-Chaabouni, Semia | Bougatef, Ali
Concerns over the environmental and waste disposal problems created by the large amounts of by-products generated from fish processing industries are increasing worldwide. The bioconversion of those marine waste by-products through the enzymatic hydrolysis of their protein content offers the possibility for the development of bioactive peptides for use in various biotechnological applications. The present study aimed to investigate and evaluate the biological and functional properties of smooth hound (Mustelus mustelus) protein hydrolysates (SHPHs) obtained by treatment with intestinal and gastric enzyme preparations from M. mustelus viscera and porcine pancreatin. The results revealed that the SHPHs exhibited different degrees of hydrolysis and antioxidant activity. The hydrolysate produced by the intestinal crude extract presented the highest rate of antioxidative activity, showing an IC₅₀ value of 1.47 ± 0.07 mg/mL in 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assays. The alkaline protease extract from the intestine of M. mustelus produced hydrolysate with the highest angiotensin I-converting enzyme (ACE) inhibitory activity (82 ± 1.52 % at 2 mg/mL). All the protein hydrolysates showed excellent solubility and interfacial properties that were governed by pH. The major amino acids detected in SHPHs were glutamic acid/glutamine, aspartic acid/asparagine, histidine and arginine, followed by methionine, phenylalanine, serine, valine and leucine. Overall, the results indicated that smooth hound by-products can be used to generate high value-added products, thus offering a valuable source of bioactive peptides for application in wide range of biotechnological and functional food applications.
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