نشریه علوم و تکنولوژی محیط زیست
سال سیزدهم شماره 3 (پیاپی 50، پاییز 1390)

Awareness of petroleum leakage in oil refineries is a vital issue in environmental investigation of water and soil pollution. During war between Iran and Iraq, leakage of enormous oil and its refined products from storage tanks, pipe lines, and refinery units of Abadan refinery to surrounding environment had occurred. Also, leakage of petroleum and its products during the existence of Abadan refinery to surrounding environment had led to conduct this research for determination of extension and quantity of oil pollution of underground layers of Abadan refinery. Location of twenty boreholes was investigated by considering petroleum leakage to surrounding area during and after war. Geological underground layers of Abadan refinery was determined from coring during drilling of the boreholes. Oil saturation, porosity and density of cores from underground layers were measured. Finally the quantity of existing petroleum in underground layers of Abadan refinery was estimated.

Construction and operation of dams have two main effects on streams. At first it increases detention time and then leads to thermal stratification. Changing of water quality is the result of these effects and the outflow has different physical, chemical and biological characteristics from inflow.In this study thermal regime in proposed Bakhtyari reservoir was simulated with CE-QUAL-W2 model. The inputs are reservoir topography, hydrological and meteorological data. As there is no chance to calibrate or verify the model, they will be done in monitoring and operation period. Three different inflow scenarios were simulated based on dry, normal year. Simulation results represent that in dry year stratification starts at April and remains up to September, but the results of normal year indicates that Stratification is between May and November. In all scenarios a stagnant layer could be seen in downward of outlet structure(700mASL).It is concluded that in dry years which dam has a major effect in inflow regime, turnover is mostly conform thermal stratification theories in reservoirs. Because of long detention time, transitional zone have turnover periods like lakes and there is not stagnant layer like near the dam.

Tailings from metal mining operations were conventionally disposed of as slurry in an engineered surface impoundment near a mine-mill complex. Such disposal can lead to a variety of environmental and other hazards, such as dust generation, dam failure, and leakage. Additional disadvantages may result from the requirement for large amounts of land with limited long-term beneficial use, as well as aesthetic impacts. Paste and thickened tailings technology is becoming recognized as an alternative for minimizing the engineering and environmental challenges commonly associated with the disposal of mineral wastes conventional tailings storage facilities. Paste is simply dewatered tailings with little or no water bleed that are non-segregating in nature. This paper focuses on some environmental and operational benefits associated with disposal of tailings in paste form.The environmental benefits of surface disposal of paste can be divided into two main categories; first, very little free water is available for generation of a leach ate, thereby reducing potential impacts on receiving waters and biological receptors. Second, the paste production technology allows for production of an engineered material by modifying the paste geochemistry in such a manner that environmental benefits result.Because of environmental risks related to gold beneficiation, a Paste Production and Storage Mechanism (PPSM) were installed in Agh-Darreh gold beneficiation complex. Research results are as follows: 34%reduction in tailing volume, 14% reduction in fresh water and required Sodium cyanide, 2 million U.S $ economic saving in construction of tailing dam, and decrease of environmental pollution of beneficiation complex.

Environmental pollution in metropolitans due to rapid growth of using gasoline as the main fuel in transportation sector has become one of the most important problem in national level, so substituting clean fuels in this sector could be one of the most effective options.The main question which this research is going to answer is the beneficiary (non-beneficiary) of converting Tehran's taxis from gasoline to Compressed Natural Gas (CNG) in order to decrease social costs that should be interpreted as increasing social benefit's factor. In this article, after reviewing the current concepts and principles of social costs and their measuring methods, social benefits of substituting gasoline with CNG are evaluated. Considering the existing figures, reduced social costs as a result of this substitution are calculated.The results of this research suggests that substituting gasoline with CNG in Tehran's taxis reduces the social costs of using gasoline (about 63.8 Million US $). As a matter of fact this substitution increases the social benefits equivalent at mentioned figure.

Because of less supervision on small industries, environmental standards are applied in lower degrees and as a result, the environment will become comparatively more polluted. In this regards, 32 small industrial centers in city of Sari were investigated by cluster branch sampling and contingent valuation method (CVM), and consequently, the effects of different variables on industries’ willingness to pay in order to reduce the environmental pollution were identified. Results of estimation showed that the higher effect in acceptation of bids is related to industrie's monthly income. By one percent of income growth, probability for acceptation of bids for environmental preservation was increased by 0.4124 units. In this study, variables such as industrial pollution, managers’ environmental information, managers’ level of education, indigenous managers, and industrial monthly income showed positive and significant effect in acceptation of bid for environmental preservation in the province. Conversely, variables of constant industries’ capital, number of industrial labors, and the amount of offered bid and average of salaries showed negative significant effect in this regards. By application of CVM estimation, annual and monthly WTP of small industries in order to preserve environment was estimated at 180842.55 and 2170110.60 Rials, respectively. Thereafter, these quantities can be used in taxation and persuasive guidelines towards the reduction of environmental pollutions.

Expansion of pollution and increasing of different needs of human societies have raised solid waste productions. Daily average of 7,450 tons of solid waste production and a day-by-day decrease in the capacity of Kahrizak landfill bear, urge the need of a new site for this purpose in the city of TehranThis problem, however, requires an Environmental Impact Assessment report at the feasibility and site selection study according to the approved decisions of the High Council of Environment. The proposed site with an area of 1000 hectares is situated at Hassan Abad Road, off Houshang Abad. This area is situated in the hydrological zone of Saveh – Zavieh. Shour River which is located 10 kilometers off the center of the proposed landfill. The soil in this area is Bazark type. The area's vegetation includes native species, which have been sampled during field work. There are rare and endangered species which have been determined. Inhabited Wildlife of the area and the endangered species have been determined.Application of the assessment was carried out by means of Monavari 2001 Method. By this method, the assessment has been considered for each of the construction and operation phases of a matrix. The results show the earthworks have most negative, significant and important impacts on plants and wildlife. There are most long term negative impacts on vegetations. There are no mitigation measures for reduction of vegetation destruction on the study area

As a Permanent Wetland, Howr-al-Azim is a very important habitat in protection of resident and migratory water bird generations. Because of having high diversities and outstanding abundances in wetland ecosystems, birds are the most important key groups of vertebrates in wetlands. For this purpose, the study was carried out to examine monthly changes in water birds and waders population, Density and diversity on 7 selected sites from January until September 2008. The results showed that 53 species from 10 families of water birds and waders were presented in the wetland with a population of 80000.In general, the species seen consisted of 60% wintering, 23% breeding and 17% resident birds; 5.6% of all the species are classified as "Threatened Species" according to Red Data Book of IUCN. During the study period, water bird's maximum population (32103) was seen in January 2008.Comparing water bird's population density on all sites showed that the density was reduced considerably from the north of the wetland (Shahid Bakeri Road, near Neisan River) towards the middle parts of the wetland (Shat Ali), so as in January, Shat Ali site showed the least density of 2 birds per hectare among all the selected sites.

Human being has made its own environment undesirable in cities by adverse changes on it, so in order to recreate, refresh and rest, mankind needs to get faraway to difficult accessible places. Nowadays tourism industry which is a human intrinsic need turns to one of the important activities and economic indicator for countries and has played a highly important role in country's national benefits in economical and cultural section. The "Dare eshgh" zone which is located in Chahrmahal- Bakhtiary province is one of the regions that has full potential for developing ecotourism. This region has capability for developing various tourism activities such as wild life, Canoe polo, mountain and rock climbing. Village and tribe tourism is another tourism potential of this area. In addition, this area is the origin and habitat of various herbal and animal species which increases the environmental sensitivity and importance of this area. Developing sustainable ecotourism needs establishment and planning comforting facilities. Also sensitive bio-factors such as soil, water, herbal resources, wild life, must be considered so the ecological potential of the land must be recognized by assessment and determine land suitability for preservation, recreation or other activities. In this research localizing tourism village is assessed based on Dr Makhdom's model and is performed by GIS instruments. Between areas that have tourist potential "Dare more" was recognized suitable for recreation activities. This area is over hanged to "Dre eshgh waterfall" which has the most important view of region- and accessible road. In addition most lands of this region has low slope. In order to increase ecotourism activities, some other facilities such as camping sites need to be placed. This area is introduced as recreation centre and as long as other potential ecotourism activities do not endanger the protection of the environment, can be considered as wide refreshing activities.