Journal of Environmental Studies
Year:2007 | Volume:33 | Issue:41|Papers Count:18

Increase in population and development of various industrial and agricultural activities, makes supply of enough water with appropriate quality an ever increasing difficult task. On the basis of various researches different types of hazardous and perhaps dangerous chemical substances have been observed in the water supply reservoirs of large cities. A large proportion of these chemical substances contain organic material. Drinking water of Tehran city is mainly from surface water which are treated in ordinary plants where no units are considered for removal of organic pollutants. Therefore, knowledge of the organic materials is necessary. In the present research, the inflow of the organic material to the treatment plant emphasizing on TOC and also percentage of its removal were measured separately from April to October. Considering the average concentration of the organic material on the plant outflow, changes are necessary in conventional water treatment plants. In majority of the treatment plants including present case, disinfection byproduct is carried out before pre-chlorination. Therefore production of side materials from primary disinfection is not impossible and solutions are suggested accordingly. Finally, the TOC in waste water resulted by wash out of the filters and raw water are compared.

In this study, by using two pH controller, NaOH and Ca(OH)2 the effectiveness of the tannin-contained extracts (acorn extract of Quercus branti) in removing chromium from tannery wastewater was examined. Therefore a native species of oak tree in Kohkiloye & Boyerahmad province, namely Quercus branti that its fruits contain more tannin than other existing oak species in Iran was selected. After drying, crushing acorns into a powder and extracting, the average percent of tannin in the extracted acorns was 10.5%.Then,in order to study impact of tannin extract with and without pH controller (Ca (OH)2 & NaOH) on reducing Chromium concentration, two Samples, from chromium standard solution(Cr III=25mg/l, Cr VI=25mg/l , equal to total Cr concentration of 50 mg/l & pH=3.5) as well as tannery wastewater (Concentrated wastewater containing Cr=3200mg/l , pH=3.98 & diluted wastewater containing Cr=160mg/l, pH=4.38) have been collected and tested. Laboratory tests were conducted in bench scale and room temperature (20-25 °c), the summery of results mentioned below: By adding a concentration of 70 mg/l tannin extract to chromium standard solution, the concentration of chromium reduced to 20% which this removal percentage was increased to 58% by increasing tannin concentration to 100 mg/l together with 70mg/l Ca(OH)2 to the Cr standard solution (pH=4.11). In the other hand adding a concentration of 10 to 100 mg/l tannin extract to the Cr standard solution, in which the residual Cr concentration was decreased to 18.52 by adding Ca(OH)2 and NaOH, pH decreased from 6.99 to 6.76 and Cr removal efficiency was fallen from 63 to 55%.However adding a concentration of 50 to 1000 mg/l tannin extract to alkaline tannery wastewater, which its pH was increased by Ca(OH)2 and NaOH from 4.38 to 9.28 and remaining Cr concentration was decreased from 160 to 7mg/l, pH level decreased to 7.95 and Cr removal efficiency reduced from 95.62 to 80%.Therefore, it was concluded that in alkaline limit (in average from 7 to 10 ) which pH has a crucial role in removing chromium, it seems there is a relationship between increase in tannin extract concentration and decrease in pH level that will be culminated to release more chromium from precipitation phase into the solution phase.

Use of passive samplers has major advantages with respect to weight, cost and maintenance. In order to measure ambient concentration of nitrogen dioxide, a diffusion type passive sampler was made and then investigated. The manufactured samplers were exposed to ambient air in parallel with continuous chemiluminescence's analyzer during weekly to four-week periods. The results show good repeatability as well as good agreement between passive and instrumental methods. Optimum time of exposure was found to be one week.

Halophilic microorganisms have important roles in bioremediation and transformation of the toxic metal compounds in polluted environments. Identification of toxic metal tolerant strains is the first step in applying them in bioremediation processes. In these investigations 90 strains of bacteria were isolated from various salty environments (soil, water and waste water) in Iran. Among them, moderately halophiles and halotolerants were 49 and 41 strains respectively. The resistance patterns, expressed as MIC, to the toxic oxyanion of K-tellurite at 34°C and 168 incubation period were determined ( 0.1 up to 16mM), by using agar dilution method. Minimum Inhibitory Concentrations (MIC) of the CHWI (salt tolerant) and the QW5, QW6 (halophilic), showed maximum resistance to K-tellurite (16, 10 and 12mM respectively). The impacts of salinity (1,5,10,15%w/v NaCl) and various concentrations of the selenooxyanions (5,10,20,25,50,75,100 mM) on the toxicity of the K-tellurite were determined. Tellurite MICs in QW5 and QW6 were highered but in the CHWI was lowered when the NaCl concentrations were increased from 1% to 10%.When K-tellurite was used plus Na-Selenite, the results obtained showed that the MIC in the halophilic strains were increased significantly, whereas, it was decreased considerably in the salt tolerant strain.

Basaltic lava flows of Maku area is the largest quaternary basalt of the north west of Iran, which is erupted from newest activity stage of Ararat Mountain volcanoes. Important portion of these lavas are reached the river Sari so and Bazargan Plain from eastern and southern slopes of the Ararat that after covering of this plain it has changed the route to wards the Maku valley of the Zangmar river and from their inters in to the Poldasht Plain. This noncarbonated fractured rocks is covered the old rivers alluvial and formed a good basaltic- alluvial aquifer in the area.Amount of fluoride ion in the water of this aquifer is more than the universal maximum admissible concentrations. All the people of villages that their drinking water supplies from basaltic springs and wells are suffering from dental and probably skeletal fluorosis. In this study for determining the source of high fluoride concentrations in the ground water of the basaltic area in addition to studying 11 microscopic tine sections from basaltic rocks of the study area, three series water sampling from the springs and rivers were carried on and chemically were analyzed. The water analysis results and basaltic rocks petrography indicate the high fluoride water inters the study area from the river Sari so route.

The Hamadan-Bijar Gas Transfer Pipeline has the duty to transfer sweet gas to northern and northwestern regions of the country. According to regulations of DOE, establishment and operation of gas transfer lines needs carrying out EIA studies. Due to linear nature of this project it is necessary to compile a particular methodology for carrying out these projects. For this purpose, first attempt has been made to obtain a real knowledge of the environment where the project is going to be carried out through conducting library and field studies. At the same time, having reviewed the technical resources of the project, all the activities of the 2 constructional and operational phases were detected. Finally two checklist methods of explanatory and Leopold matrix were chosen to study EIA. With due regard to the compiled methodology it was necessary to use RS and GIS tools, in all stages of identification and conduction of this project, in studying the current environmental conditions, environmental routing of the choices, and preparing precise applied drawings for gas transfer line. The results of the study show that although the environment will incur many damages due to soil excavation operations, earth filling and explosions that may be necessary in some places, performance of this project particularly on operation phase, would be of great local, regional and national benefits because of its socioeconomic advantages. In another words, constructional and operational of this project is quite in accordance with the goals of sustainable development in three mentioned levels. Also carrying out this study suggests that using RS and GIS tools is not only inevitable in the process of performing these types of projects (linear projects) but it provides the environmental assessors with very precise informat ion in order to achieve applied results. The method of using these tools has been discussed to a great extent in this article.

Generally, the mountains in due to the difference Altitude, Volume of relief, form and exposition are organization by variety microclimates: Differences in pressure, temperature, humidity, light, thermal energy, precipitation (and kind of it) and winds give a special form. Valley, Slope, Pick have the specific microclimates: Mountain is defined by bioclimate classification. Thermal inversion often exists in the valley regions and accompanies by fog, Katabatic and Anabatic exist in the mountain regions. While foehn (chinok) is a warm and dry wind and has an environmental impact, Mountain is and important obstacle against movement of air masses, the ascending Mountain air is very important, in this paper, a model of mountain precipitation studied. Damavand as the highest mountain in Iran is situated near East of Tehran and has originated on essential microclimates and environmental impacts.

Gaia theory has provided scopes for new discussions especially in the context of environmental science identity and philosophy, modeling, and developed studies in the area of climatology in the last two decades. Gaia theory has resulted in the creation of new supporting groups particularly the echo feminist parties. Such parties believe that human being should not manipulate the natural order of the earth. According to this theory, the whole existence is something more than its components and it is not possible to get the knowledge about the whole through each one of the components. Therefore, we should use a whole seeing approach for knowing the entire. This approach that is different from individualistic or existentialistic ones, respects other components of the nature and emphasizes on this point that the interaction between the live structures cannot be done only by material frameworks and factors, but non-materialistic elements also play role. There are two main points being emphasized in this theory, the first one being that the continuation of stability and the survival of the existing environments depend largely on the existence of specified or certain borders and boundaries. And secondly those living organisms that have good interaction with their environment, and their interaction shows a common co living leave a large amount of benefit for the future generations and hence provide higher survival chances.

Biodiversity is essential for human survival and economic well being and for the ecosystem function and stability. In this study, two classification methods were used simultaneously for determining ecosystem units. 111 plant species in 58 plots were appropriated to four unites: unit 1 (Pyrus syriaca), Unit 2 (Quercus infectoria group), Unit 3 (Q. brantii) and unit 4 (Rosa caniana). Six diversity and evenness indices consist of: Shannon's (H¢), Simpson's reciprocal, Hill's N1 Pielou's J ¢, Alatalo's F and Molinari's G were calculated. One way ANOVA and Duncan's multiple comparison tests were used to study differences among ecosystem units. Q. infectoria and R. caniana units had more species diversity than others. Slope, aspect, elevation, trees and herbal percent coverage were used in analyses. Discriminat analysis result to construct discriminant function based on slope percent and Molinari's index.

Soil fertility decline and sustainable production of pure plantations of fast growing trees in long time, are the main reasons fore utilization of trees with the ability of nitrogen fixation in mixed plantations. The objective of this study was to survey the effect of pure plantation of Populus eurmaericana (Dode) Guinier and mixed whit Alnus subcordata C.A.Mey on soil properties. In order to investigate soil chemical and physical properties, soil were sampled at 0-15, 15-30 and 30-60 cm depths from the plantation that were located in the next of Chamestan station and also some blank samples were collected (3 samples from the soil that were located out of plantation). The collected samples were transferred to the laboratory and several properties of them such as: texture, pH, Ec, organic matter, organic carbon, total nitrogen and some available nutrients (K, P, Ca, and Mg) were determined. Results showed that, the maximum amount of Nitrogen, C/N ratio, organic matter and electrical conductivity were observed in 0-15 and 15-30 cm depths of mixed plantations. Totally, the presence of Alnus in plantations of populus was an important factor in improvement of soil fertility and sustainable production.

The objective of this study was to determine plant species diversity in the understory ofloblolly pine plantations in different stages of growth. To conduct this study, random-systematic sampling method was used, and plot area was obtained using Whittaker's nested plots and species / area curve. Within each plot, woody and herbaceous species were identified, and percentage cover was estimated according to abundance-dominance criterion of Braun-Blanquet. In order to data analysis, Shanonn-Wiener's diversity index and Smith and Wilson evenness and Jacquard similarity indices were used. Results indicated that the number of plant species (richness) were 25, 38, 48, 42 and 32 in seedling, small sapling, large sapling, bole tree of growth stages and natural forest, respectively. The highest and lowest of plant species diversity were found in the large sapling (non-thinned forest) and seedling growth stages, respectively. Also, plant species diversity was higher in large sapling than bole tree (thinned forest) plantations, but there was no significant difference between them (P>0.05). The jacquard similarity index in the large sapling and bole tree plantations were higher than seedling and natural forest.

Great Cormorants are dependent on marine and freshwater wetlands, and are top-predators in the ecological food-web and are thus particularly exposed to habitat loss, pollution and other human activities affecting such habitats. Reproductive performance in Great Cormorant was studied during the 2003 breeding season (early March-late July) at Ramsar colony. Factors influencing breeding success were taken in study. Mayfield and Maximum Likelihood methods were used to estimate nest survival during incubation stage and nestling stages. Mean brood size was 3.03 and early-breeder pairs had significantly larger broods. A positive relationship found between nest size and both brood size and number of chicks fledged. Breeding success was 2.88 per nesting attempts (80% of initial eggs). The difference in reproductive success between early and late breeders was not significant. There were higher Daily Survival Rate in later stages of chick rearing than the incubation stage and main losses occurred in incubation stage. Results suggest that Ramsar colony site provide more favorable situation for breeding Great Cormorants' than other studied colonies.

In this paper, Concept of "village" can be defined in two ways: substantial and actual. Substantial definition of the village is related to the concept of "settlement". its subjective definition, causing to approach to the concept, considers some methods, such as: referring to dictionaries and related definitions, achieving historical knowledge about the concept and its development process through the time, recognizing its circumstances and comparing it with the City- as a phenomena which is in interaction or interrelation with the village and finally the theory of its structure. As a result, it is going to think twice about the concept of "village". It may consider village, as a "settlement" with a dynamic structure, which develops according to its potentials.