INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH (IJER)
Year:2010 | Volume:4 | Issue:2|Papers Count:21

Having access to locations struck by natural environmental disasters is one of the chief necessities in urban disaster management. This paper aims to study different physical and semi-physical patterns for increasing access to different districts in a city through applying changes to the present network of routes. To attain this goal, District 6 of Tehran Municipality was selected for the case study. The technique used in this research is based on multi-criteria decision- making methods. Thus, the patterns and indices were extracted by means of AHP method, and then the indices were assigned weights. These patterns were, then, analyzed and ranked through TOPSIS, FUZZY and SAW techniques respectively. Next, the results were combined by means of Borda method. The results indicated that A4 pattern which obtained 7 maximum scores was the most efficient pattern in increasing access through changes in the network of routes. Next to it is A3 pattern which ranked second. It is, therefore, suggested that in order to increase access for rescue operation in urban disasters, parallel routes in directions of the first and second priority, east to west aand north to south, must be constructed so that arterial roads in the district offer better services in normal and emergency conditions.

This paper deals with the suitability of agricultural and municipal organic wastes as growing media components for ornamental plants. Nine growing media prepared by mixing the main components of peat (P), hazelnut husk (H) and maize straw (M) with the fertilizer sources of municipal solid waste compost (C), bio-solid (B) and poultry manure (Pm) were compared against soil-based (C1) and peat-based (C2) controls. The suitability of such mixtures for use in soilless media was evaluated using their physico-chemical characteristics. To investigate the impact of mixtures on plant growth, two different pot experiments, including the plants of ligustrum (Ligustrum lucidum) and cypress (Cupressus macrocarpa), were conducted for two years. Physical and physico-chemical properties of mixture indicated that peat and soil were successfully replaced with hazelnut husk, maize straw, MSW-compost, bio-solid and poultry manure. The effect of fertilizer additives on plant growth was more pronounced than that of the main components. Therefore, among the present mixtures, the most suitable one for ligustrum was the mixture containing poultry manure, whereas for cypress was bio-solid, regardless of the main components.

In this study, the performance of electro-coagulation in combination with aluminum sacrificial anode, in removal of zinc and copper has been investigated. Several parameters, such as pollutant concentration, pH, electrical potential, COD, turbidity and contact time were studied to achieve a higher removal capacity. Variable concentrations (5-50-500 ppm) of zinc and copper solutions were prepared. In order to follow the progress of the treatment, samples of 25mL were taken at 15 min intervals up to 60 min and then filtered with 0.45 diameters to eliminate sludge formed during electrolysis. The varying pH of the initial solution was also studied to measure their effects on the zinc and copper removal efficiency. Results obtained with synthetic wastewater revealed that the most effective removal capacities of studied metals could be achieved at 40 V electrical potential. In addition, the increase of electrical potential, in the range of 20-40 V, enhanced the treatment rate without affecting the charge loading required to reduce metal ion concentrations under the admissible legal levels. The process was successfully applied to the treatment of an electroplating wastewater where an effective reduction of zinc and copper concentration under legal limits was obtained, just after 15-60 min. Moreover, it can be concluded that the electro-coagulation process has the potential to be utilized for the cost-effective removal of heavy metals from water and wastewater.

Heavily polluted wastewater from sanitary landfill presents the leachate characteristics that need special treatment and disposal. Concentration of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), heavy metal and other pollutant content are often larger than standard requirement after applying biological/physico-chemical treatment. Thus, the combination of coagulation flocculation and chemical oxidation treatment has been investigated. Using the jar-test procedure and stirrer, the physico-chemical conditions were optimized. It concerns the most effective coagulant between ferric chloride (FeCl3) and poly-aluminum chloride (PACl), the optimal pH and the H2O2 as the most effective chemical oxidant. The optimum pH and dosage of PACl and FeCl3 were obtained as 7 and 2.0 g/L, 5 and 1.0 g/L respectively. Iron salts were proved to be more efficient than aluminum ones, resulting in COD reduction (up to 59%) whereas the corresponding values using alum was lower (50%). The optimum pH and dosage of PACl and ferric chloride for optimum oxidation process was; 300 mg/L at pH7 and 300 mg/L at pH 6 respectively. Oxidation process gave significant effect to the removal of suspended solids and turbidity (up to 94%) using supernatant contain with ion Fe3+ at pH 7.

Karkhe watershed (KW) with more than 5 million hectares recently encountered many problems in the natural, social and man-made habitats. Unsuitable use of land, soil erosion and lack of rainfall are the most destructive factors in this watershed affecting the whole region fundamentally.As expected, these problems have caused a considerable fall in biodiversity in fauna and flora, a decrease in volume and quality of water resources in watershed and a rise in probability of destructive floods. In this study the changes in land use levels and erosion were assessed in 5 sub-regions of Karkhe watershed in two periods of time ’1988 and 2002’ using images of LANDSAT. In addition, the effects of these manipulations on the physico-chemical qualities of water such as, cation and anion concentration, acidity and salinity were quantified. The results show that erosion changes in Karkhe Watershed are inconsiderable from 1988 to 2002. The extent of urban area and irrigated agricultural lands in Karkhe sub-regions (Gamasiab, Gharresu Kashkan ) are around 1000 and 2000 km2 respectively , the decrease in river discharge around 121.6 m3/s , is the most effective factors for the reduction in acidity(from 7.9 in 1988 to 8.1 in 2002), an increment in salinity ( from 1.6 mg/L in 1988 to 3.6 mg/L in 2002 as average amount of SAR in all sub-regions of watershed) and the high density of the anions (from 8.1 mg/L in 1988 to 16.4 mg/L in 2002) and cations (from 8.8 mg/L to 16.5 mg/L) in Karkhe River.

Nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer of west Texas were compiled, mapped, and analyzed in the context of local geology and land use. Alluvial deposits of sand, silt, clay, and gravel compose the unconfined aquifer. Ranching and farming are predominant land uses in the rural study area. Data were tabulated from 79 water wells with a median depth of 75 m and mapped with a geographic information system (GIS). The wells were sampled between the years 2003 and 2008. Total dissolved solids (TDS) concentrations in the aquifer were very high, with a median value of 2,687 mg/L. Approximately 18% of observations exceeded the 44.27 mg/L drinking water standard for nitrate, whereas 6% exceeded the 10mg/L standard for arsenic, and only 4% surpassed the 50 mg/L standard for selenium. There was a statistically significant, direct correlation between arsenic and selenium, as well as between nitrate and selenium concentrations. Moreover, arsenic and selenium concentrations were significantly higher in shallower wells. Probable sources of groundwater contamination in the study area include natural (geological) sources and agricultural activity.

Water contamination due to the wide variety of pesticides used in agriculture is a global environmental pollution problem. In order to reach at sub-mgL-1 levels of detection, an efficient extraction technique is required. A simple, fast and economical method, dispersive liquid-liquid micro extraction (DLLME), followed by gas chromatography-mass spectrometry was assessed for determining endosulfan in water samples. Experimental parameters which control the performance of DLLME, such as extraction and disperser solvents type and their volumes, temperature, and salt addition were studied by experimental design. The main factors affecting the extraction efficiency, volumes of disperser and extraction solvents, were optimized by response surface method. Under optimum conditions, the method was linear over the range 0.1-50 mg/L. The enrichment factor and extraction recovery were 163.4 and 63.73, respectively. Correlation coefficient and limit of detection (LODs) are 0.9996, 20 ng/L, respectively.

Industries in developing countries add new production lines producing altogether different waste stream. This newer waste invariably finds its way to existing anaerobic treatment system causing gradual/sudden change in feed substrates affecting its steady performances. This study investigates steady response of anaerobic reactors subjected to sudden change in feed substrate types, assesses its impact on biomass and explores possibility of restoring pre-changed steady responses again. Three suspended growth batch anaerobic reactors (R1, R2 and R3) were started-up and operated in three different phases. In Phase–I, all the reactors were operated for 65 d on jiggery feed at an organic loading rate (OLR) of 1.40 kg COD/m3 d to obtain steady responses. In Phase–II, the change in feed substrate types were applied suddenly to R2 (from jaggery to cerelac) and R3 (from jaggery to neutralized acetic acid) while keeping R1 as the control and operated for 64 d on the same OLR. R2 gave steady response with reduced biogas production whereas complete cessation of biogas production was observed in R3. The total methanogenic activity of R3 biomass yielded comparable values with R1 and R2 biomasses indicating preservation of biomass integrity. When R2 and R3 were restored suddenly again with jaggery feed in Phase–III at the same OLR, R3 recovered quickly and all the reactors gave similar steady responses comparable to Phase–I.

Denitrification of high- nitrate high- salinity wastewater is difficult due to plasmolysis and inactivation of denitrifiers at high salinity conditions. In this study, the effects of salinity and empty bed contact time (EBCT) on simultaneous heterotrophic and sulfur based autotrophic denitrification of synthetic wastewater were evaluated in an up flow packed bed reactor .The reactor was filled with granular elemental sulfur particles with diameters of 2.8-5.6 mm and porosity of 40%. The initial culture was prepared from sludge of Shahrak-e- ghods domestic wastewater treatment plant. The influent nitrate concentration and EBCT were 600 mg NO3-N/lit and 16 h respectively. First, the stoichiometric fraction of nitrate removed by heterotrophic denitrification (with methanol as organic carbon source) supplied enough alkalinity to compensate the autotrophic alkalinity consumption, was determined 60%. Then, salt concentration was gradually increased with NaCl from 0% in the feed. The Process kept high nitrate removal efficiency (>99%) even at 3.5 % NaCl. During these changes the alkalinity variations were insignificant which showed the microbial population ratio of acclimated autotrophic to heterotrophic denitrifiers had no any significant changes with NaCl concentrations up to 3.5% in the feed. At 4 and 5% NaCl, the efficiency drastically decreased to 78% and 48%, respectively. Similar behavior was also observed for methanol removal efficiency, effluent turbidity as an indirect determinant of biological mass and sulfate production. The effects of flow rates on denitrification of synthetic high nitrate high salinity wastewater with 3.5 %NaCl under mixotrophic condition were also investigated by increasing the flow rate from 7.06 lit/day to 70.6 lit/day with corresponding EBCT 20 to 2 h. Denitrification efficiency was close to 100% at EBCT of 20 to 8 hr, but decreased to 79% and 39% when the EBCT was 4 and 2 h, respectively. The decrease in effluent sulfate concentration (as an indicator for autotrophic denitrification) and the increase in effluent alkalinity (as an indicator for heterotrophic denitrification) and pH at EBCT of 4 and 2 h were considerable correspondingly. These results imply that the population ratio of autotrophic to heterotrophic denitrifiers depends on EBCT.

Bake-out was executed against the newly constructed apartment buildings using two methods to find out the effect of improvement on the indoor air quality and identify the concentration changes in the indoor air by the bake-out method for 3 months after occupancy. From two methods of bake-out executed before occupying, we did not find any reduction effect on the hazardous substances in the indoor air. The concentration of the hazardous substances in the indoor air tended to increase due to the sink effect, but it turned to decrease due to enough ventilation by desorption. The extent of adsorption depends on hazardous substances, building materials and furniture. The longer the period of bake-out is noticed when the formaldehyde concentration was higher than that from the total volatile organic compounds (TVOCs) because of sink effect. Therefore TVOCs had more reducing effect on the concentration of indoor air hazardous substances than the formaldehyde. The concentration level of indoor air contamination materials could be reduced from the re-desorption of hazardous materials through a sufficient duration of ventilation although bake-out has raised the concentration level of indoor air contamination materials by the adsorption effect for a short period of time.

Hara Biosphere Reserve in southern Hormozgan province with 85686 hectares areas is located between Bandar Khamir and Queshm Island. This area can be considered as the most spectacular regions of Iran for a unique coastal Seascape. Mangrove forests and amazing biodiversity make thisregion as the most significant ecotourism areas throughout the country. This research attempts to determine recreation value of Mangrove forests and willingness of the tourists to pay for ecotourism areas using Contingent Valuation Method and dichotomous choice questionnaire. Socio-economic assessment of the study area was carried out through the analysis of the touristfilled questionnaires in 2006 based on proper and logical time and place distribution. Logit model was used to determine the willingness of individuals, because the model’s parameters are based on methods of Maximum likelihood. Results show that 81.2 % of the individuals are willing to pay for recreation value forms of Mangrove forests. The annual average Willingness-to-Pay for this region is us 5 per visit. Moreover, the annual economic value of Mangrove forests was estimated us 97.5/ acre which shows Existence values of these kinds of forests and also the necessity for planning to employ the recreation capabilities in the study area.

In this study, a bacterial species which could remove lead from wastewater was isolated from lead contaminated soil prepared in the laboratory. Based on the biochemical and morphological characterization the bacteria were identified as Brevundimonas vesicularis. The biosorption potential of powdered dry biomass of B. Vesicularis was investigated by batch adsorption experiments. It was found that, the bio-sorption capacities were significantly affected by the pH and initial concentration of the solution, bio-sorbent dosage and contact time. Batch and isothermal studies were carried out at optimum pH of 4. The rate of bio-sorption was found to be fast during the initial 10min and it reached equilibrium by 60min. Langmuir isotherm model was suitable for describing the bio-sorption of lead by B. Vesicularis. The results indicated that, the dry biomass of B. Vesicularis is suitable as an efficient bio-sorbent for the removal of lead from wastewater.

An ion chromatography (IC) method for simultaneous determination of benzoic, salicylic and sorbic acids was developed. In this method the samples were purified by solid-phase extraction. The analytes were then eluted with methanol from C18 cartridge. The separation was performed on ion-exclusion column by an isocratic elution with 0.25 mmol /L sulfuric acid solution containing 20% (v/v) acetone as elute. The calibration curves showed good linearity with suppressed conductivity detection. Under this condition, separation of the three components was achieved in less than 23 min. The detection limit calculated as the concentration corresponding to three times the background noise, was 0.1, 0.15 and 0.2 mg/ L for benzoic acid, salicylic acid and sorbic acid respectively. The method was successfully applied to analysis of various cosmetic products.

This paper discusses the results of the full-scale field measurement study to investigate the most efficient application strategy of the Hybrid Turbine Ventilator (HTV) in improving the indoor thermal comfort in hot-humid tropics. The effects of three different HTV application strategies performance on improving the levels of indoor air temperature, relative humidity (RH) and air velocity were evaluated for a three-clear day period. The results were analyzed and compared based on two thermal comfort indices i.e. Operative Temperature (OT) and Standard Effective Temperature (SET*). The study shows that the HTV for the occupied space with extractor fan at ceiling level is the most efficient strategy when it succeeded to reduce indoor air temperature and relative humidity of up to 0.7°C and 1.7%RH, respectively. It also succeeded to induce air velocity in the occupied level up to 0.38m/s in average and reduced the level of OT by 60% and SET* by 90% compared to the existing condition. The overall results also indicated that the performance of the HTV could be enhanced by applying the device for both occupied space and attic space at the same time and ensure that openings are kept opened.

Earlier, environmental problems have been considered as technical and economic problems. In the last decades of the twentieth century the societal dimensions of environmental problems and environmental issues attracted more public attention. As a result of this circumstances a new social scientific discipline, “environmental sociology” was appeared to investigate the environmental behavior of the societies. This paper is an attempt to investigate the environmental issue in grate Tehran and design a structural model for explaining environmental Attitude and behavior of urban residents. To achieve this objective a conceptual model derived out from review of literature to examine structural relations among personal factors, attitude towards environment and environmental behavior. To examine this model, 1200 individuals of Tehran residents were randomly chosen and interviewed about their opinion on environmental legislations, environmental knowledge and information, environmental attitude and behavior. The results of this study show that for Tehran residents the environment is not yet thought to be an important problem, when compared with other social and economic issues. Overall, results of the survey show that people are ready to spend time or to organize themselves to take part in a campaign to protect the environment, but they believe that money for environmental protection should come from the government. The structural model indicates that, feeling of stress, environmental information, preparedness to act and environmental legislation have an important impact on environmental attitude and behavior.

The spatial and temporal distribution of heavy metals in water, sediment and fish (dry weight basis) of Buriganga River, Bangladesh were determined by atomic absorption spectrophotometer. In water concentration of Pb, Cd, Ni, Cu and Cr varied seasonally and spatially from 58.17 to 72.45μg/L, 7.08 to 12.33mg/L, 7.15 to 10.32mg/L, 107.38 to 201.29mg/L and 489.27 to 645.26mg/L, respectively. Chromium was the most abundant in the water of Balughat during pre-monsoon, whereas, Cd was the most scarce in the water of Shawaryghat during monsoon. The sediment also showed spatial and temporal variation of Pb, Cd, Ni, Cu and Cr ranged from 64.71 to 77.13 mg/kg, 2.36 to 4.25 mg/kg, 147.06 to 258.17 mg/kg, 21.75 to 32.54 mg/kg and 118.63 to 218.39 mg/kg, respectively. Among all the metals studied in sediment, Ni was the highest at Foridabad during pre-monsoon and Cd was the lowest at Shawaryghat during monsoon. In six species of fish studied, the concentration of Pb, Cd, Ni, Cu and Cr varied seasonally from 8.03 to 13.52 mg/kg, 0.73 to 1.25 mg/kg, 8.25 to 11.21 mg/kg, 3.36 to 6.34 mg/kg and 5.27 to 7.38 mg/kg, respectively. Of the five metals studied Pb concentration was the highest in Gudusia chapra during monsoon, in contrast, Cd concentration was the lowest in Cirrhinus reba during post-monsoon. Some of the heavy metals’ concentrations are higher than the recommended value, which suggest that the Buriganga is to a certain extent a heavy metal polluted river and the water, sediment and fish are not completely safe for health.

Manganese and cobalt concentrations in hair and nail were determined by Flame Atomic Absorption Spectrophotometer (AAS).The mean manganese in hair and nail were 0.54 ± 0.35mg/g and 0.68 ±  0.30mg/g while the mean cobalt in hair and nail were 0.30±0.24mg/g and 0.460.37mg/g respectively. A progressive increase in cobalt concentrations in hair and nails with age indicated no significant difference in their means suggesting that cobalt in hair and nails originate from a common source. Comparing the mean manganese concentrations in hair with the nails a significant difference is indicated in the two tissues (pdd0.05). Human hair and nails are hence recording filaments that can reflect metabolic changes of many elements over long periods of time and hence furnish a post nutritional event of some essential micro-elements.

A rapid and reproducible method is described that employs solid phase extraction (SPE) using dichloromethane, followed by gas chromatograph-mass spectrometry for the determination of toxic toluene, xylene and cumene (TXC) from different lake water of Dhaka mega city of Bangladesh. The method was applied to detect and quantify TXC in water samples collected from surface and 30 cm depth of water. Fifty milliliters of pretreated methanol and filtered water samples were applied directly to a C18 SPE column. TXC were extracted with dichloromethane and the TXC concentration was obtained to be 2.34 to 52.12 ppm. The factors influencing SPE e.g., absorbent types, sample load volume, eluting solvent and temperature, were investigated. A cartridge containing a C18 absorbent and using solvent gave a better performance for the extraction of TXC from the lake water samples. Average recoveries exceeding 90% could be achieved for toluene at 24°C with a 2.8% RSD.

The toxicity of 7 herbicides to the three cyanobacteria was tested in this work. The results indicated that: (1) There was a highly significant relationship between dried weight or chlorophyll-a and OD680nm for tested cyanobacteria; (2) the toxicity of the tested herbicides with the order from high to low was: photosynthesis-inhibiting > ACCase inhibitor > protox inhibiting herbicides; (3) the sensitivity of various species exposed to cyanazine, diclofop, prometryn, simazine and simetryn varied by over one order of magnitude. The decreasing order of sensitivity of cyanobacteria to the selected herbicides was: M. Flosaquae > M. Aeruginosa > A. flos-aquae. Cyanobacteria can produce toxins including hepatotoxins e.g. microcystins and endotoxins e.g. lipopolysaccharides. Therefore, the research on comparing the differential sensitivity of cyanobacteria and green algae is of important scientific significance and realistic value.

The degradation of crude oil under a no-control and dispersant-control setting was evaluated using loss of biological activity test, microbial population growth and measurements of optical transmittance of test media. Comparison of the toxicity of crude oil under the no-control setting to crude oil-dispersant mixture revealed that the mixture was about 2 times more toxic than the crude oil under the no response strategy. Furthermore, the results of the toxicity testing experiments also showed that under the no-control setting, there was a loss in the toxicity of the crude oil from 6.03mL/L - 9.43 mL/L compared to crude oil-dispersant mixture where the toxicity of the crude oil-dispersant mixture was found to remain fairly constant with LC50 value of the mixture ranging from 4.0 mg/L to 4.38 mg/L over the 28 days experimental period. On the basis of the regression coefficient factor (R2), loss of biological activity during the no-control setting was found to be about 3 times more than under the dispersant-control setting. The result of the measurement of optical transmittance of crude oil depicting rate of emulsification under the no-control and dispersant control settings revealed that level of light transmittance under no-control setting ranged from 0% to 84%, while under the dispersant-control setting light transmittance ranged from 0% to 72% over the 28 days of observation. The derived regression factor (R2) however revealed that under the dispersant-control setting, the rate of emulsification and degradation of crude oil was faster (R2 = 0.96) than under the no-control setting (R2 = 0.77). The result of the microbial growth assays also revealed that under the dispersant-control setting, the numbers of microbial colony forming units was about 7 folds higher than the number of colony forming units observed under the no-control setting. The usefulness of the methods for assessing crude oil degradation and its implications for choosing dispersants and making decision on whether or not to deploy dispersants for oil spill control are discussed.

This study investigates the application of landscape ecology in planning and design of urban ecological systems. The ecological approach to landscape planning and the concepts of designing and implementing ecological systems have gained increasing attention in the last two decades. However, the ecological systems of urban environment need more research to consider built and natural patches and corridors together and to provide proper and applicable strategies that meet all of the diverse aspects of planning and designing sustainable urban systems. This approach could help in defining sustainable landscape development, aiming for a balance between both physical and natural systems in urban areas. This research is focused on Tehran’s metropolitan area as a case study to provide a relationship between landscape ecology and urban planning and design to propose a model for analyzing and providing strategies and policies for conserving and resorting urban ecological systems. The spatial structure of green and natural areas are studied and categorized based on the patch-corridor-matrix model. Overlaying the selected layers helped provide strategies for conservation and reclamation, and policies to improve the structure and function of urban landscapes. The strategies to restore the ecological structure and to develop its function in Tehran metropolitan area are based on structural congruence, aggregate with outliers, local compensation and indispensable patterns.