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Synoptic approach to forecasting and statistical downscaling of climate parameters (Case study: Golestan Province) Полный текст
2017
Ghanghermeh, Abdolazim | Roshan, Gholamreza | Nasrabadi, Touraj
The present study attempts to introduce a method of statistical downscaling with a synoptic view. The precipitation data of Golestan Province has been used for the years 1971 to 2010. Employing multivariable regression, this study models the precipitation gauges in the station scale, by making use of 26 predicting components of model HadCM3, on the basis of two A2 and B2 scenarios. However, the minimum predicting components for precipitation in station scale included 26 components for one grid to 390 atmosphere circulation components for the 15 suggested grids. Nevertheless, results indicate minimum error, related to the precipitation models, based on projecting components of the studies of 15 grids. By applying this selected method, the precipitation gauges for 2020 to 2040 has been simulated. General results of the precipitation changes for the yearly decennial average of Golestan Province indicates additive stream of this component, based on both A2 and B2 scenarios. Yet this yearly decennial addition of precipitation go with seasonal and annual changes, i.e. getting drier in summer as well as its subsequent increase in draught issue on one hand, and increased centralization of precipitations in the winter and lack of its proper distribution during year on the other. As a result, changes in local patterns of precipitations throughout the province is promising for maximum increase of precipitation for the farthest southwest area of Golestan, greatly potential for decreasing precipitation of sub eastern area.
Показать больше [+] Меньше [-]Removal of caffeine from aqueous solution using multi-wall carbon nanotubes: kinetic, isotherm, and thermodynamics studies Полный текст
2017
Bahrami, Mehdi | Amiri, Mohammad Javad | Koochaki, Sara
The occurrence of contaminants in wastewaters, and their behavior during wastewater treatment and production of drinking water are key issues to re-use water resources. The present research aims to remove caffeine from aqueous solutions via adsorption technique, using Multi-Wall Carbon Nanotubes (MWCNTs) as an adsorbent under different experimental conditions. The processing variables such as pH (2-12), contact time (1-30 min), initial concentration of caffeine (2-314 mg/L), temperature (25, 50, 80 °C), and adsorbent mass (0.02-0.15 g) have been investigated with equilibrium and kinetic studies on adsorption of caffeine onto MWCNTs being also developed. Maximum caffeine removal has been obtained at pH=7 and adsorption equilibrium has been achieved in 5 min. The use of pseudo second-order kinetic model with determination coefficient of 99.3% (R2=0.993), has made the adsorption kinetics to be well fitted. The caffeine equilibrium adsorption data have been best fitted to Langmuir-Freundlich Model with a relatively high determination coefficient of 96.5% (R2=0.965) and maximum adsorption capacity of 35.61 mg/g of caffeine on MWCNTs. The thermodynamic parameters display that the adsorption of caffeine onto MWCNTs has been non-spontaneous and endothermic in nature.
Показать больше [+] Меньше [-]Polycyclic aromatic hydrocarbons in air from industrial areas in Lagos and Ogun states, Nigeria Полный текст
2017
Salaudeen, Ibrahim | Sonibare, Oluwadayo | Sojinu, Samuel | Ekundayo, Olusegun
There is currently scarce information on the occurrence and distributions of Polycyclic Aromatic Hydrocarbons (PAHs) in the air from industrial estates in Nigeria. Hence, the present study aims to evaluate the extent and sources of pollution of polycyclic aromatic hydrocarbons in the air from some industrial estates in Lagos and Ogun States, Nigeria. Ten air samples have been collected from the industrial estates in Lagos (Ogba and Ilupeju) and ten from Ogun (Agbara and Ota) between October and November, 2014, using low volume air sampler. Also five further air samples have been collected from Epe town, located in the outskirts of Lagos, where there are no industrial activities to serve as control. The concentrations and distributions of 20 target Polycyclic Aromatic Hydrocarbons (PAHs) in the air samples have been determined by gas chromatography-mass spectrometry. The concentration of ∑20PAHs ranged from 89.20 to 96.48 ng/m3 (with an average of 92.84 ng/m3) and 72.52 to 142.91 ng/m3 (with an average of 107.72 ng/m3) in the air samples from Lagos and Ogun industrial estates, respectively. The air from the control site has a total ∑20PAHs concentration of 19.55 ng/m3 (9.78 ng/m3 in average). When compared with global data, these values show that the air samples have been moderately polluted. PAHs in most air samples are mainly from pyrolytic sources, which may have resulted from diesel fuel combustion and high vehicular emissions, typical of industrial activities in the area.
Показать больше [+] Меньше [-]Acute toxicity of povidone-iodine (Betadine) in common carp (Cyprinus carpio L. 1758) Полный текст
2017
Forouhar Vajargah, Mohammad | Mohammadi Yalsuyi, Ahmad | Hedayati, Aliakbar
Organisms in aquatic environments are exposed to a number of pollutants such as pharmaceutical residues. As such, the aim of the present study is to achieve the Lethal Concentration (LC50) of Povidone-iodine (Betadine) for Cyprinus carpio. To do so, the study employs samples, weighing 4±1 [mean±SD] gr, and carries out an experiment in static condition. Based on OECD instructions, after a period of 4 days under controlled water, the physicochemical factors give the following results: pH= 8-8.3, BOD= 690 mg/l, total hardness= 210 mg, and CaCo3 and temperature= 17±0.1 °C. All fish are acclimatized for 10 days in an aquarium, 60×55×30 cm in size, which included the control group (no toxic concentration) as well as the treated aquariums, with Betadine concentration of 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 400, and 600 mg/l. LC10, LC20, LC30, LC40, LC50, LC60, LC70, LC80, LC90, and LC95 have been measured for 6, 12, 18, and 24 hours. LC50 24h Betadine for C. carpio has been 158.273 ml/l, showing no mortality after 24 hours (i.e. 48h, 72h, and 96h). Results of the present study suggest that Betadine is practically nontoxic and not irritant at low concentrations for this species and it has a short half-life in aquatic environments.
Показать больше [+] Меньше [-]Microbio-ecology and hydro-geochemistry of saline sulfur springs of Ghale-Madreseh, Khuzestan, Iran Полный текст
2017
Papizadeh, Moslem | Roayaei Ardakani, Mohammad | Fakour, Hossein | Ghaderi, Golgol | Firouzei, Yavar
Ghale-madreseh is the first point that the saline and sulfurous streams flow into Tembi River, one of the well-known saline rivers in Khuzestan province, Iran. This river is one of the main sources of increasing Karun River’s salinity, which is the largest river in Iran in terms of discharge. There are three saline and sulfurous springs (Shour-1, Shour-2m and Namak Springs) as well as a drinkable one (Shireen spring) in Ghale-madreseh region. Normally, most probable number counting of sulfate reducing, sulfur oxidizing and nitrate reducing bacteria showed that there are different patterns of microbial populations in the springs of Ghale-madreseh region. The observed differences are highly attributed to the hydro-geochemical properties of the springs. It is assumed that the groundwater which streams in the Gachsaran formation receives considerable amounts of SO42- (0.09-0.1 M), Na+ (1.654-3.604 M), and Cl- (1-548-3.775 M) by halite and gypsum dissolution, resulting in the saline and sulfurous springs on the Gachsaran formation. Also, due to the low depth of local oil reservoirs, activity of sulfate reducing bacteria in the close vicinity of oil reservoirs and groundwater streams is highly probable. Hence, the microbial sulfate reduction may be responsible for the production of H2S, probably playing a role in the souring of local oil reservoirs. Besides, the groundwater that reaches the Bakhtiary formation shows different characteristics as detected in Shireen spring.
Показать больше [+] Меньше [-]Evaluation of visual pollution in urban squares, using SWOT, AHP, and QSPM techniques (Case study: Tehran squares of Enghelab and Vanak) Полный текст
2017
Allahyari, Hadis | Nasehi, Saeedeh | Salehi, Esmail | Zebardast, Lobat
Visual pollution, observed in urban areas, makes human beings suffer indirectly from mental distress and illnesses in long term. We are daily confronted with a variety of advertisement pictures in city squares and review them in our minds. But we may not be aware of the fact that such a visual scramble leads to mind distraction, decreasing mental concentration. The present study applies the techniques of SWOT and QSPM to identify and introduce the most influential factors, related to visual pollution, in internal and external environment of Tehran, comparing the rate of visual pollution in both Vanak and Enghelab squares. Accordingly, in SWOT matrix, strengths, weaknesses, threats, and opportunities in these squares have been investigated and, using Expert Choice, AHP method has been applied to weight them. SWOT as an analytic instrument can be used for evaluation purposes in QSPM system. Finally, using the Quantitative Strategic Planning Matrix (QSPM), the selected strategies have been prioritized. The results of the study indicate that Vanak Square has an invasive strategy and Enghelab Square, a conservative strategy. Aided by QSPM matrix, the study has offered eight prioritization strategies, introducing the best possible strategy for these squares. Regarding visual pollution, Vanak Square has a better position than Enghelab square.
Показать больше [+] Меньше [-]Analysis of Chemical and Microbial Contents of Public Swimming Pools’ Water in Akwa Ibom State, Nigeria Полный текст
2016
Antia, Mfon | Umoh, Akaninyene
This study assessed the chemical and microbial contents in the water of public swimming pools in Akwa Ibom State, Nigeria. A total of 16 public pools were selected through probability sampling from the 32 pools that existed in the five urban areas of Akwa Ibom State. Water samples were collected from the sampled pools and tested in the laboratory for chemical and microbial contents. Results showed that the chemical contents of most pools in the study area were less than the values recommended for effective disinfection of the pools. Average free chlorine ranged from 0.05 mg/L to 1.15 mg/L 200 Cfu/ml permissible, except for pools L and M, with 1.8×102 Cfu/ml and 1.7×102 Cfu/ml, respectively. Mean fecal coliform ranged from 2.0×103 Cfu/ml to 4.4×103 Cfu/ml >10 Cfu/100 ml permissible, except for pools L and M, with 0.0 Cfu/ml. It could therefore be concluded that only one out of every eight public swimming pools in Akwa Ibom State meet the minimum requirement for both chemical and microbial contents. This simply implies that most public swimming pools in the study area are not safe for users.
Показать больше [+] Меньше [-]Investigation of Spatial Structure of Groundwater Quality Using Geostatistical Approach in Mehran Plain, Iran Полный текст
2016
Khosravi, Hassan | Karimi, Kamran | Nakhaee nejadfard, Sara | Mesbahzadeh, Tayebeh
Groundwater is a major source of water for domestic, industrial, and agricultural sectors in many countries. The main objective of this research was to provide an overview of present groundwater quality using parameters such as calcium, magnesium, sodium, chloride, sulfate, pH, and electrical conductivity (EC) in the Mehran plain, Ilam province using GIS and geostatistical techniques. A total of 23 deep and semi-profound wells were selected based on the classified randomized sampling method. The sampling locations were obtained by GPS. Plastic containers were used for the collection of water samples. These samples were transferred to the laboratory for analyzing water quality parameters. Statistical characteristics, qualitative data interpolation, and zoning were investigated using SPSS 20 ،GS+5.3 and ArcGIS10.1. Kolmogorov–Smirnov test were used to test data normality. In order to normalize parameters, logarithm, and 1/x were used for sulfate, EC, cation, and anion. Then the variogram analysis was performed to select the appropriate model. Results showed that co-kriging is the best method for cation and anion, whereas local polynomial interpolation is suitable for sulfate. The results of the interpolation of groundwater quality factors showed that there is approximately good adaption among groundwater factors and geomorphology and topology of the region. Because of inappropriate irrigation system, the highest concentration is in the northwest and western parts of the region, where there is the minimum height and maximum agricultural land. Growth of arable land and agricultural activities has caused increasing concentrations of studied elements, especially EC.
Показать больше [+] Меньше [-]Alterations in the Plasma Thyroid and Cortisol Hormones in Yellowfin Sea bream, Acanthopagrus latus, following exposure to Benzo(α)Pyrene Полный текст
2016
Alijani Ardeshir, Rashid | Rastgar, Sara | Movahedinia, Abdol-Ali | Yarahmadi, Zahra
The goal of this research is to study the effect of benzo-alpha-pyrene (BαP) as a pollutant on the plasma levels of cortisol, thyroxin (T4), and triiodothyronine (T3) hormones, and the T3/T4 ratio in the yellowfin sea bream, Acanthopagrus latus. The BαP (50 mg kg-1) in vegetable oil was peritoneally injected. Blood samples were obtained from the treated and control groups after 3 and 72 hr, respectively. The amounts of cortisol, T3, and T4 were measured using the ELISA techniques. The results showed that during both the 3 and 72 hr BαP exposures, the T4 hormone levels significantly decreased, although the cortisol levels increased (P<0.05). However, the T3 hormone levels and T3/T4 ratios compared with their control groups showed a significant difference just after 72 hr (P<0.05). The disruptive effects of the BαP exposure on T4 was stronger than that on the T3, being more evident in long-term stress. Thus, the BαP exerts a significant effect on the thyroid endocrine system and consequently on fish metabolism and growth.
Показать больше [+] Меньше [-]Contamination by trace elements of agricultural soils around Sidi Bou Othmane in abandoned mine tailings in Marrakech, Morocco Полный текст
2016
Yassir, Barkouch | Sana, El Fadili | Alain, Pineau
This study was carried out for the purpose of investigating the issue of tailings dams as a potential source of contamination by trace elements in soils at the Sidi Bou Othmane mine in the Marrakech Region, Morocco. Soil samples taken from depths of up to 15 cm and within a radius of 50 m from the tailings dams, were analyzed for Cd, Cu, Pb and Zn using atomic absorption spectrometry. Average concentrations of Cd, Cu, Pb and Zn in soils around the abandoned tailings dams were, respectively, 157.2±8.8, 969.1±38.7, 1640.7±42.7 and 2846.8±84.6 mg/kg. Soils in the vicinity of the decommissioned tailings dams registered increased values for Cd, Cu, Pb and Zn. Contamination factors (CF) and pollution index (PI) were calculated in order to estimate the anthropogenic contribution of target pollutants which determined Cd, Cu, Pb and Zn as the main pollutants in this region. The results revealed the polluted areas in the vicinity of the mine, especially two rural communities apparently linked to the lack of appropriate measures to counteract the effects of these mine tailings, which were causing a progressive contamination of the soil with residues of heavy metal emissions in this region under study. Improved strategies for the management of tailings, among other factors, might have influenced the reduced level of contamination by trace elements at the abandoned mine tailings dam sites.
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