Journal of Environmental Studies
Year:2003 | Volume:29 | Issue:31|Papers Count:22

Conventional remedial technologies of excavation/retrieval, treatment, and disposal methods for contaminated groundwater are expensive, disruptive for the hydrology of ecosystem, and are of low efficiency. Thus, because of these limitations, in situ technologies have been developed as alternatives. For the treatment of groundwater contaminated with uranium pollutants such a treatment has been developed to minimize the mobility of the uranyle ion by transferring it to a stable phase via chemically or biologically induced formations. Zero valent iron reduction (ZVI) process has been known for years but has only recently been applied to clean up environmental contamination.Not knowing the mechanism of the decontamination process, different forms of ZVI- materials have been synthesized for groundwater remediation, whereas important quantities of scrap iron from the steel industries are discharged or recycled all over the world. These include carbon steel, low alloy steel, cast iron and all other iron containing alloys. The objectives of this research were as follows:1- the reduction of uranel ions by Fe0 to form the sparingly soluble U species2- UO22+ adsorption onto iron oxyhydroxide corrosion products: and3- A combination of both reduction/precipitation and adsorptionIt is important to note that these subjects have been studied regarding to laboratories tests and column studies and also the effect of different parameters such as pH.

In this study n analytical solution model, which is capable to predict salinity at various locations of a river connected to the sea, by considering tidal conditions, has been developed. To illustrate the ability of the developed model, it has been applied to Karoon-Bahmanshir-Hafar river system to predict their salinity situation. In this model sea tidal conditions have been considered. The model is also applied to the system in order to predict critical existing salinity situation and the worst probable salinity conditions in the future. In addition, salinity concentrations at Bahmanshir branch for various upstream discharges of fresh water boundary conditions have been predicted.

The Houbara Bustard is the only species of the genus Chlamydotis, which is subdivided into three sub-species, and the nominate race of Chlamydotis undulata macqueenii is a familiar bird of the desert plains of Iran. The purpose of this research was to find out the suitability and importance of various habitats for the Houbara, and the role of habitat in the conservation of the species. Relevant information from 30 areas was collected, analysed and ranked respectively according to suitability for Houbara protection. The results showed that Dasht-e-Mobarakeh and Siah Kuh (35 15 N, 50 40 E) with HIS=0.84 was identified as having the best habitat conditions with the fewest threat factors, while the Mogham plain (27 20N, 56 50E) with HIS= 0.51 was the least suitable and was faced with severe threat elements. A map showing the distribution of the Houbara in Iran was carefully prepared.

The Horizontal Roughing Filtration (HRF) has been developed as a proper pretreatment for Slow Sand Filtration during 20th century. In some cases it was used for iron and manganese removal from ground water resources. The performance of this kind of filters was improved by a limited dose of coagulant agents like iron or aluminum salts during the two last decades of 20th , and named as Direct Horizontal Roughing Filtration (DHRF). This kind of filters with a simple design, construction, operation and maintenance and using natural filter media, without any complicated mechanical parts, are classified as Low Cost Treatment Methods and used for villages and small communities. The main problem in operation and maintenance of HRF and DHRF is the weak cleaning performance with conventional hydraulic washing methods.The main targets of this research study were: 1. Evaluation of the effects of the hopper shaped under drain compartments on head loss control and development of sediment washout efficiency, regarding the increasing of washing velocity and shear stress through the porous filling media. 2. Evaluation of the effects of air application on the cleaning efficiency of DHRF system during the hydraulic washing process.The results of this study in comparison with the reports presented by other researchers show that, with preparing hopper shaped compartment, at the bottom of the filter box, it acts as the sediment accumulation zone, and with continuous deposit removal, the head loss development during a filter rum would be controlled, as well as, it causes a very good improvement in washing performance and cleaning efficiency. The results of pilot study with a maximum run time of one week between two washing applications, show that with a filtration rate up to 5.6 h/m, the head loss was less than 3 centimeters and maximum accumulation of deposits on the filter media was 2% in weight. The results of air application in pulses during the washing process causes a reduction in deposit accumulation rate form 18% up to 24% in different compartments of pilot filter in DHRF conditions.

In the present investigation conservative/ nonconservative behavior of Cu, Cd, Pb, Co, Fe, Ni, Zn, and Pb in sediments and suspended particulate matter (SPM) of Tadjan river During mixing with Caspian Sea Water has been studied. Results showed that before mixing of the river and sea water SPM carry higher concentrations of Mn, Pb, Fe, Co, Zn and sediment contain higher concentrations of Ni, Cu and Cd. Mixing experiment revealed that from and overall point of view Cu and Fe tend to remove from solution onto SPM and other metals desorbed from SPM to aqueous phase. In sediments also all metal showed descriptive behavior except Fe. It could be said that in SPM, Co and Cu, to some extent, and Co in sediments show conservative behavior during mixing, of river and sea, water. Concentration of other metals in sediments and SPM showed variations during mixing. Correlation coefficient and cluster analysis revealed that in sediments, concentrations of Cd, Pb, Mn and Cu were under control of pH as well as Mn, Cd and Pb in SPM of the river during mixing. It seems that behaviors of Co, Fe and Ni and Zn in sediments depend on some environmental characteristics of water other than pH, TOC and salinity.

Determination of the concentrations of heavy metals in industrial discharge effluent is needed for discharge reuse and treatment. More than 700 contaminated dangerous chemical species in the water resources have been reported. The utilization of effluent discharge from chemical, fertilizer, pesticide, and textile plant is increasing.In arid region of Iran, such as Yazd Province due to shortage of water resources, the industrial discharge effluent can be reused for city green belt, forest, and park. Determination of physical and chemical analysis of industrial wastewater is required for proper treatment to avoid environmental pollution.In this study effluent discharge from four textile plants namely Yazdbaf (1), Jonoub (2), Derakhshan (3) and Taban (4) were collected monthly, for six month. The samples were analyzed for pH, Ec, Na+, Ca++, Mg++, Cl-, So4--, Co3--, HCo3-, and heavy metals of Pb, Cd, and Ni. The results of analysis were compared with Iranian Contaminant Standards. The result for plant No. (1) shows that Cl-, Hco3-, in Plant No. (2) pH, electrical conductivity (EC), Ca++, Mg++, Cl-, So4--, Hco3-, in plant No. (3) Ca++, Mg++, Cl-, Hco3-, in plant No. (4) pH, Ca++, Mg++, Cl-, Hco3- are higher than standards. Heavy metals concentrations in all plants were lower than critical level and are imposing no limitation. In summary, the results of the analysis show that pH, EC, Ca++, Mg++, CI-, So4--, Hco3-, impose limiting factors, but heavy metals impose no limitation. The reuse of wastewater require more research, especially in relation to inorganic compounds.

Ponds, which are called Ab-bandans in mazindaran province, are valuable samples of native knowledge and technology of the people of this region for the optimum use of water. These aquatic systems are used for agricultural water storage and recharge of springs and underground waters, also from ecological points of view, provide habitats for birds and wild life, protection of bio-diversity, gene banks, creation of beautiful landscapes and several other benefits. The ponds of north of Iran are in danger of degradation due to uncontrolled development, pollution of agricultural liquid waste and simplification. The present research is for recognition of the vegetation cover of these ecosystems and also studying the factors causing their degradation in the southern border of the Caspian Sea (Mazindaran Province). The results of this research show there are 423 ponds with total areas of about 14000 hectares. Their distribution is drawn on a map with the 1.300000 scale. Due to change in plant structure of these ecosystems and dominance of increasing species such as Nympha alba, Phragmites australis, Typha latifolia and Lemna minor and invasion of foreign oppurtunist plants such as Azola and also pollution because of incoming agricultural liquid waste, it seems that the ponds are losing their ecological power and are heading towads waterlogging (destrophication). Now that the world is encountered with water crisis it is recommended a scientific overall study of the ponds for their protection and sustainable use, before complete destruction of these cultural-natural heritage of genebanks, diversity and special beauty, takes place.

Qeshm island has specific ecological and environmental features. Because of being an island and as a free zone, its importance and fragile ecosystems merit more protective measures. More important may be the mangrove forests of a different types of Avicennum spp. forests. This has added to island's significance as an international biosphere reserve. During the last couple of decades accelerated development and intensive landuse without regards to its capability has destroyed basic natural resources and the natural coastal environment. Land is polluted and landuse types do not respect natural carrying capacity. Future development of Qeshm island depends on the degree of respect to natural landscape capability. Much more because of its vulnerability which is faced with accelerated population growth. A system approach was adopted for landuse capability evaluation and integrated land suitability for various types of development and specially (eco-) tourism. Resulting zones of various capability for diverse landuse types were then overlayed on administrative divisions map for its practical application in future development planning. Qeshm has many great potentials for all types of landuse, yet according to environmental evaluation, and by presence of biosphere reserve, its potential for integrated tourist and protection is greater. It has relatively little capability for industrial and agricultural development. At last it should be emphesized that the island can easily enjoy an environmental management system for its future sustainable development, what is rather imposible or very difficult for the whole country because of geographic and administrative complexities. Qeshm's EMS planning is one great specific advantage that this largest island of Persian Gulf may relay upon.

 With the considerable and continous attention of individual, academics, and governments to the issue of environmental sustainability, in the three late decades of the 20th century, the demands for 'sustainable urban development' and sustainable cities seem to be the most pressing challenge facing humanity in the twenty-first century.On the other hand, the search for the ideal city, the city form that would be able to express both the advantages of modern technology and the soul of rustic life, on the basis of enlightened ideas of social justice, has long been a major concern to many philosophers, social reformers, writers, and architects and planners. This search, which in its historical roots might be traced back to the Greek philosopher, Plato, and his Republic, resulted in some contradictory socio-political and economic philosophies, and has influenced the development of different types of urban settlement throughout history. In the second half of the twentieth century, with growing awareness of environmental problems and ecological crises, the search has been transformed to address the question: what is the sustainable city? There are many uncertainties in the identification of alternative urban forms. This paper examines the two predominant and contradictory theories that are put forward as the grounds for achieving sustainable city forms: the Compact City and Urban dispersal ideas. A study of four different urban forms in the U. K., which were selected and examined systematically in terms of their densities and land, uses, is described. The results are mostly supportive of the compact city, particularly in terms of energy efficiency and accessibility to the city facilities.

For achievement of sustainable development, conservation of environment and natural resources is a must. Paying attention to societies needs and NGOs for compensating the governmental planning for conservation is vital. This potential of interest in conservation of environment and natural resources could be found in various groups of society including villagers, women, students, experts etc. This study was performed for considering the capability of NGOs for this aim with answer sheet method in Mazindaran province. The results were analyzed by Q-square statistic test. Some results of this research show: 62% of respondents were in the age of 20-40 years old. 84% of them were male. 58% had academic education and all of them were literate. 58% of them had knowledge of at least one foreign language. 12% of them had Internet facilities and 32% had computer. 8% of respondents were member of at least one NGO and 8% were acquiescent of this membership. 60% of their NGOs are active in environment and natural resources conservation and other 40% are working in welfare goals. 88% of respondents are interested in membership of new NGOs for conservation of environment and natural resources. 36% like to be a responsible member, 40% want active membership and 24% want ordinary membership. 42% of respondents believe that education and extension about NGOs is not sufficient and suitable. 78% of respondents believe that NGOs for conservation of environment and natural resources have an important and essential role in the society. 30% of them prefer local level for activity of NGOs for this goal, 20% prefer regional level, 28% prefer national level and 22% like to work in international level. In total, results show that the respondents are interested to participate in NGOs and the potential for establishment of NGOs for conservation of environment and natural resources in the study area is rather high.

Ecotourism is a new trend in tourism industry. Beautiful landscape and natural views are the focal points and tourist-attraction points of this tourism. Thus, it is necessary to consider the importance of its role in environmental preservation to achieve a sustainable development. Although, the relative importance of ecotourism is still lower than collective or traditional tourism, it is gaining an increasing validity and reliability in some countries. Ecotourists travel to natural and genuine parts of earth and gain valuable experiences for their own motifs. They join to nature preservation and friends groups after getting insight on cultural-environmental aspects of the nature of each region and country. The certain fact is that tourism activities influence environment and to prevent or control negative effects on environment. The policy makers and planners should predict basic needs of tourists on one hand and think of the positive and negative effects of tourism on the other hand, when preparing detailed and comprehensive plans.After long years of makind's life in earth, the natural landscapes and sceneries are exposed to the dangers and risks resulted from human activities. To confront this increasing risk and danger, an urgent need is felt in global level to make people aware of the importance of preserving natural resources as a critical issue and to start a new movement to obtain active participation of people, particularly local people of any region to preserve natural resources and landscapes and present it as a tourist goods. The World Tourism Organization; too, recognizes sustainable development as an activity that not only preserves natural and cultural resources, but also increases the capacity to create job and earn income.