فهرست مطالب

Environmental Health Science and Engineering - Volume:7 Issue: 1, 2010
  • Volume:7 Issue: 1, 2010
  • تاریخ انتشار: 1388/12/01
  • تعداد عناوین: 11
|
  • M. Taheriyoun, M. Karamouz, A. Baghvand Pages 1-14
    Determining the trophic status of the reservoirs is not a precise process and contains vagueness. Fuzzy set and entropy theories are concepts which can model uncertainty and imprecision in the data and the analysis. In this study, an Entropy-based Fuzzy Eutrophication Index model has been developed for classification of trophic level of Satarkhan Reservoir in the north-western part of Iran. Through the Fuzzy Synthetic Evaluation technique, trophic levels were considered as fuzzy sets and a fuzzy evaluation matrix was formed by defining the membership function of water quality indicators. The indicators were weighed by integrating both objective and subjective criteria. In this regard, the entropy method was used to determine the objective weights of the indicators based on the amount of useful information available in the data set and the subjective weight was determined by the analytical hierarchy process using a pairwise comparison done by the expert judgment. Classification of the trophic status of the reservoir was determined by multiplying the weighed vector by the fuzzy evaluation matrix. The results showed that critical months for eutrophication in Satarkhan reservoir occur in autumn and spring after the overturning phenomena. The strength of the results of developed entrophy-based fuzzy entrophication index is that the trophic level in each month was expressed with a degree of certainty. Also due to the ability of the model to integrate different kinds of objective and subjective quality observations considering the information included in the data, the proposed model is more robust than the previous index models such as Trophic Status Index and fuzzy trophic index.
    Keywords: Trophic level, Reservoir, Fuzzy Synthetic Evaluation, Entropy, Analytical hierarchy process
  • EFFECT OF HYDROPHILIC AND HYDROPHOBIC ORGANIC MATTER ON AMOXICILLIN AND CEPHALEXIN RESIDUALS REJECTION FROM WATER BY NANOFILTRATION
    M. A. Zazouli, M. Ulbricht, S. Nasseri, H. Susanto Pages 15-24
    Antibiotics such as amoxicillin and cephalexin are a group of pharmaceutical compounds in human medicine practice that have been entered in water bodies. Presence of these compounds in the environment has raised concerns regarding the toxicity to aquatic organisms and the emergence of strains of antibiotic-resistant bacteria. Removal of these substances before entering the aquatic environment as well as water reuse plant is very important. The objective of this investigation was to evaluate the impact of hydrophilic and hydrophobic fractions of Natural Organic Matter (NOM) on the removal efficiency of cephalexin and amoxicillin, by using two different commercially available composite NF membranes (TFC-SR2 and TFC-SR3). In addition, the effect of NOM fractions on retention mechanism and permeates flux behavior was studied. Amoxicillin and cephalexin were used as models of antibiotics; alginate and humic acid were used as models of hydrophilic and hydrophobic fractions of NOM, respectively. It was observed that the rejection and permeate flux of amoxicillin and cephalexin were influenced by the membrane characteristics and properties of NOM. The results showed that as the alginate proportion was increased, the rejection improved. The permeate flux decreased with increasing alginate ratio. It was observed that the rejections of amoxicillin and cephalexin in TFC-SR2 were >97.3% and >95.8% in all experiments, respectively. In TFC-SR3, the rejection percentage were (95.9%-100%) and (86.1%-96.3%), respectively. Alginate and humic acid had synergistic effect on flux decline. In other words, increasing alginate concentration increased the rate and extent of flux reduction.
    Keywords: Natural Organic Matter fraction, Nanofiltration, Antibiotic removal, Fouling, Amoxicillin, Cephalexin
  • M. Mohammadian Fazli, A. R. Mesdaghinia, K. Naddafi, S. Nasseri, M. Yunesian, M. Mazaheri Assadi, S. Rezaie, H. Hamzehei Pages 25-34
    Synthetic dyes are extensively used in different industries. Dyes have adverse impacts such as visual effects, chemical oxygen demand, toxicity, mutagenicity and carcinogenicity characteristics. White rot fungi, due to extracellular enzyme system, are capable to degrade dyes and various xenobiotics. The aim of this study was to optimize decolorization of reactive blue 19 (RB19) dye using Ganoderma sp. fungus. Response Surface Methodology (RSM) was used to study the effect of independent variables, namely glycerol concentration (15, 20 and 25 g/L), temperature (27, 30 and 33 oC) and pH (5.5, 6.0 and 6.5) on color removal efficiency in aqueous solution. From RSM-generated model, the optimum conditions for RB19 decolorization were identified to be at temperature of 27oC, glycerol concentration of 19.14 mg/L and pH=6.3. At the optimum conditions, predicted decolorization was 95.3 percent. The confirmatory experiments were conducted and confirmed the results by 94.89% color removal. Thus, this statistical approach enabled to improve reactive blue 19 decolorization process by Ganoderma sp. up to 1.27 times higher than non-optimized conditions.
    Keywords: Dye, Decolorization, Reactive blue 19, Ganoderma sp., Response Surface Method
  • FACTORS AFFECTING ROAD TRAFFIC NOISE ANNOYANCE AMONG WHITE-COLLAR EMPLOYEES WORKING IN TEHRAN
    I. Alimohammadi, P. Nassiri, M. Azkhosh, M. Hoseini Pages 35-42
    noise annoyance among white-collar employees working in Tehran has been carefully analyzed. This survey has been conducted by interviewing 495 citizens working in non-manufacturing industries in Tehran، using questionnaires، Weinstein noise sensitivity scale، Beck''s depression، Buss and perry''s aggression، Zung''s anxiety، job satisfaction and Eysenc''s personality inventory. These citizens were office workers or store employees. Noise annoyance was determined both by numerical-based questionnaire criterion and by verbal index. Personal information، attitudinal factors and hearing conditions were determined using a general questionnaire. The amount of workplace noise the participants were exposed to was directly measured at their workplaces. It was revealed that among personal factors، age (p=0. 030) ، marital status (p=0. 004) ، residential period (p=0. 001) and wealth (p=0. 04) were related to noise annoyance. Attitudinal factors including sensitivity to noise (p=0. 001) ، individual''s opinion on the need to control the noise (p=0. 000) and individuals'' assessment of the amount of the workplace ambient noise (p= 0. 000) were found to have relationship with noise annoyance. No meaningful relationship was seen between the equivalent noise level (p=0. 879) and statistical noise level of L90 (p=0. 909). The present study revealed that among all effective factors involved in noise annoyance، attitudinal factors had the most significant role in this regard.
    Keywords: Noise annoyance, Road traffic noise, Personal traits, Attitudinal factors
  • Gh. R. Roshan, S. Zanganeh Shahraki, D. Sauri, R. 4R. Borna Pages 43-52
    Urban sprawl beginning in the developed countries around 1950 is currently experienced in almost all countries. Many studies on the effects of urban sprawl indicate the emergence of harmful effects of this phenomenon. One of the most important environmental effects is the changes in climate. The purpose of this research was to identify
    the relation between urban sprawl components of Tehran with changes in climate variables. To this end, two data sets have been used to study the relation between these elements and components. The first data set included climatic elements such as rainfall, temperature, the percent of relative humidity and the percent of calm wind, as well as its mean speed for a period of 54 years (1953-2006). The second set of data was formed by components relevant to urban sprawl such as city area, private cars per capita, population density and number of urban population.
    Pearson correlation and multiple regression methods have been applied to compare and identify the relation between climatic components with urban sprawl indices. Results of correlation indicate that among the 5 aforementioned
    climatic components, annual rainfall and the mean of wind speed do not appear to have significant relation with sprawl, but the oscillations in percent of relative humidity and percent of calm wind seem to have a significant relation with Tehran sprawl. Consequently and using multivariate regression, it was concluded that the most important factor in the increasing temperature of Tehran, is the number of cars; the most important factor in increasing the percent of relative humidity is the area of Tehran, whereas the increase of the percent of calm wind may be attributed to the increase of population.
    Keywords: Urban Sprawl, Climate Change, Metropolis, Population Density, Tehran
  • F. Nejadkoorki, E. Yousefi, F. Naseri Pages 53-62
    A model is demonstrated that describes street traffic-induced noise pollution in 2008 in Yazd, Iran. Sound levels were measured using a Bruel and Kjaer-2260 sound level meter on 10 streets across the city over this period during the morning rush hour and different vehicle types were counted simultaneously at various sampling points. Geographical Information System was used to generate, store and retrieve the spatial data and map the sound levels using an interpolation technique. The minimum and maximum sound levels appeared to be 70.9 dBA and 80.7 dBA, respectively and these values were above the national legislated norm. Cars and motorcycles were the most commonly used vehicle type in the city, comprising 61.2% and 23.7 % of the total traffic volume, respectively. These data were followed by trucks, buses and bicycles. A number of parameters which were assumed to impact on noise pollution were collected and considered, including geographical position, elevation, the distance to the nearest intersection, street geometry and the numbers of vehicles according to class. The modelling demonstrated that there is a significant relationship between the average sound level and traffic flow (R2 = 0.5). The results showed that although street traffichas increased between 2002 and 2008, the sound levels in the city decreased slightly and this has been attributed to advances in vehicle design.
    Keywords: Noise pollution, Street traffic, Sound level, Modelling, Yazd
  • Sh. Mehrali, M. R. Alavi Moghaddam, S. H. Hashemi Pages 63-70
    The main objective of this study was to evaluate Reactive Blue 19 dye removal efficiency in aerobic sequencing batch reactor (SBR) process by adding polyaluminum chloride (PACl). PACl was added to the reactors in concentrations of 0, 1, 5, 15 and 30 mg-Al/L (SBR1 to SBR5) after filling periods. Initial dye concentrations were selected to be 40 mg/L for all reactors. The averages of dye removal efficiencies were more than 57% in all reactors. The maximum and minimum dye removal efficiencies were 71.7% ± 13.6 and 57.7% ± 34.3 in SBR3 and SBR4, respectively. According to the obtained results, PACl had not any significant effects on the COD removal efficiency. The MLSS and MLVSS concentration of SBRs had an increasing rate during whole operation time and reached from 2500 mg/L (1st day) to 4900 mg/L (39th day). The maximum increasing rate was 50% in SBR5.
    Keywords: Biological treatment, Sequencing batch reactor, Reactive Blue 19, Polyaluminum chloride
  • M. M. Amin, A. Ebrahimi, M. Hajian, N. Iranpanah, B. Bina Pages 71-80
    The purpose of this study was to undertake a spatial analysis of total organic carbon, electrical conductivity and nitrate, in order to produce a pollution dispersion and prediction map for the investigated area in the province of Isfahan in Iran. The groundwater samples were collected from a zone as a pilot study area of 80 km2, including 25 water wells, based on the criteria of vulnerability assessment projects, that is, about one well per 3 km2, during four seasons in 2008-09. In order to make any inferences about the areas that did not have well data, a statistical relationship between explanatory total organic carbon, electrical conductivity and nitrate variables related to well coordination was developed. The probability of the presence of elevated levels of the three compounds in the groundwater was predicted using the best-fit variogram model. According to spatial analysis, the highest R2=0.789 achieved was related to electrical conductivity and followed the exponential model with 0.266 for NO3- (spherical model) and 0.322 for total organic carbon (exponential model) in the spring 2009. This showed the high confidence level for electrical conductivity dataset and forecasted trends. The results of the spatial analysis demonstrated that the transfer trends of electrical conductivity in the groundwater resources followed the route of groundwater movement in all seasons. However, for nitrate and total organic carbon, a definite trend was not obtained and pollution dispersion depended on many parameters.
    Keywords: Electrical conductivity, Nitrate, Total organic carbon, Variogram, Kriging
  • N. Rastkari, M. Yunesian, R. Ahmadkhaniha Pages 81-86
    Methyl tert-butyl ether, ethyl tert-butyl ether and tert-amyl methyl ether are oxygenated compounds added to gasoline to enhance octane rating in replacement of alkyl-lead compounds. In the present study the excretion of urinary methyl tert-butyl ether, ethyl tert-butyl ether and tert-amyl methyl ether were evaluated as biomarkers of exposure to gasoline. With this aim, 10 policemen engaged in traffic control, 10 gas station workers and ten occupationally non-exposed persons were investigated. Spot urine samples were obtained prior to and at the end of the work shift from each subject. The urinary levels of oxygenated ethers were determined by using head-space gas chromatography and mass spectrometry detection. There were significant differences among the mean urinary concentrations of methyl tert-butyl ether in pre-shift samples of gas station workers (1193 ng/L), policemen (734 ng/L) and occupationally non-exposed persons (49 ng/L). The mean urinary concentrations of methyl tert-butyl ether and tert-amyl methyl ether differed significantly among post-shift samples of gas station workers (16636 and 8655 ng/L), policemen (14458 and 1472 ng/L) and occupationally non-exposed persons (324 and 59 ng/L) (ANOVA: p<0.05 and Kruskal-Wallis test: p<0.05). There was a significant difference in methyl tert-butyl ether concentrations between job categories (p<0.05 by ANOVA and Kruskal-Wallis test ), and gas station workers and policemen were found to be probably the most exposed groups in this study.
    Keywords: Methyl tert-butyl ether, Ethyl tert-butyl ether, Tert-amyl methyl ether, Urinary levels, Gasoline
  • D. Peptenatu, R. D. Pintilii, C. Draghici, D. Stoian Pages 87-96
    This study aims at analyzing the changes that the functional restructuring of economic activities developed in the communist period brought upon the quality of the natural environment. It has been done an individualization of the main areas affected by the marked dynamics of economic activities in Bucharest due to numberless sources of emission distributed all over the city. The striking lack of balance in the condition of the environment is determined by the profound alterations inside the urban structure. Once the location of performing economic activities has been shifted towards the outskirts of the city, other economic activities have been developed inside the urban structure causing tides to compress, thus exceeding the capacity for support of the road structure. As a consequence the polluting emissions are greater than the admitted maximum limits in many areas of Bucharest. Besides road traffic, numerous construction sites inside the city which are not suitably organized, add to the increase of polluting emissions. The local authorities have initiated great projects which aim at easing the traffic flow inside the city and developing systems of redirecting the road traffic at city entrances.
    Keywords: Functional restructuring, Territorial management, Urban pollution
  • B. Jannat, M. R. Oveisi, N. Sadeghi, M. Hajimahmoodi, M. Behzad, E. Choopankari, A. A. Behfar Pages 97-102
    Sesame seed (sesamum indicum L.) is one of the world''s most important and oldest oilseed crops with a high level content of antioxidant known to human health. The antioxidant factors responsible for the stability of roasted sesame seeds is highly affected by the conditions of the roasting process. Survey of the roasting temperature and time effects on antioxidants and total phenolic content in Iranian sesame seeds was the aim of this investigation. Spectrophotometer methods based on folin-ciocalteau reagent for determination of total phenolic content (TPC) and Ferric Reducing Antioxidant Power assay (FRAP) technique for total antioxidant activity were used before and after different roasting processes. Some of 8 Iranian sesame seeds cultivares were studied (n = 160), including Branching Naz, Non Branching Naz, Dezful, Darab, Karaj, Moghan, Varamin and Black sesame.The range of FRAP values was between 0.301±0.029μM and 1.746±0.083μM in Moghan and Branching Naz seasem seed cultivares, respectively. The FRAP value increased from 0.974±0.095 μ M in unroasted Branching Naz as a control to 1.746±0.083 μ M after roasting in 200ºC for 20min. Also TPCs increased significantly as the roasting temperature. The amount of TPC varied in different sesame cultivars from 20.109±3.967 μ M to 129.300±3.493 μ M in Varamin and Branching Naz sesame seed cultivares, respectively; also TPC increased from 70.953±5.863 μ M in unroasted Branching Naz sesame seed as a control to 129.300±3.493 μ M after roasting in 200ºC for 20 min .Branching Naz seasem seed cultivare was at the highest level in total antioxidants and total phenolic contents in comparison to other samples; however Moghan and Varamin cultivares were at the lowest level in total antioxidants and total phenolic contents, respectively. The present study showed that Iranian sesame seed can be considered as a good source of natural antioxidant specially after roasting. The optimum temperature and time roasting to obtain the most antioxidants and total phenolic content was 200º C for 20 min.
    Keywords: Sesame seed, Phenolic compound, Antioxidant activity, Roasting temperature, Roasting time