فصلنامه محیط شناسی
سال بیست و هفتم شماره 2 (پیاپی 28، زمستان 1380)

This article presents the findings of an environmental evaluation carried out for the city of Tehran. In year 2001 evaluation was based on a mathematical model, the subject of another study prepared for the evaluation of the urban environmental quality of major Iranian cities. The model includes qualitative and quantitative features of a city, forming the whole structure of the model. Those characteristics of the model that would contribute to the quality of urban environment, have been classified on the basis of their importance in the structure of the model. Accordingly, in a hierarchical order a proper value has. been assigned to all the characters of the model. The purpose of this numerical approach is to conclude a figure (proxy), that regarded as the urban environmental quality index of the city of Tehran, in the year that data have been collected. ' The degree of efficiency of the model depends on the availability of data and statistics for the year under consideration. This model is regarded as an efficient tool for evaluation of urban quality of the major Iranian cities. Further the results of this model can be used to overcome possible planning deficiency and to find the degree of impact of implemented environmental policy for enhancement of the urban environmental quality.

In this research, health, safety, and environmental risks were studied for the final compost products in Iran. Municipal solid waste (MSW) is the major feedstock for composting plants and the main users are farmers. According to the objective of this research program three factors including heavy metal concentrations, foreign matter content, and maturity degree were identified as important parameters. The values were measured in the ready-for-sale compost produced in the active Iranian composing plants. This results showed that the amount of foreign matters and the stone of all compost samples were less than the standard values and the samples were either practically free from the above mentioned matters or had a very little amount. In all compost samples the maturity grade, which is very important with respect to the pathogens removal, was in comply with EPA-503 standard, except for Saleh Abad with the maturity grade of III, which needs further fermentation. But the major problem for Iranian compost goes with the heavy metal concentrations in the final product which makes it unsuited to the agricultural applications. The concentrations of copper, cadmium, and zine had the highest differences with the standard values, respectively. For example, copper concentrations had a difference about 4.5 to 8 times by comparing the compost samples with a German standard (which is 100 mglkg). For other heavy metals (Cr, Ni, Pb), except for a few cases, the concentrations at the compost exceeded the standard levels e.g., chromium values, except for one of compost plants, were at least 2 to 2.5 times greater than the standard values.

Growing of urban societies, city development, appearance of metropolice and increasing of municipal solid wastes as well as many urban difficulties all are serious threats to the environment and public health of any given society. These problems, in addition to the need for having temporary waste transfer stations for the transport to the main landfill sites, is another important point to many problems in hand. A study is conducted on. the environmental impact of transfer stations for transport of wastes, especially noise pollution and leachate of unpleasant odor as well as noise during the activities of these sites. Samples were taken from solid waste leachings in small semi-trailers and measurment of average noise level by sound recorder during refuse collection was done at nights from 00:00 hour midnight until 02:00 am and duringmorning hours from 06:00 until 07:30 am. A questionnairewas also prepearedand completed by neighboring people living near these areas. The main results show that majority of people enhabiting near these stations were complaining of noise pollution at nights as a result of activities in these sub-stations. 85% of inhabitants were to dissatisfied from unpleasant smells emitted from these sub-stations. Questionnaires were also compieted, considering the health and probable effects of sound and unpleasantodor pollution among transport personnel in these statioIls. More than 95%. of 'the working personnel lack necessary information and sufficient education for performing their duties. The results also showed that the rate of. pollution of leachate at the ground level is more than the standard level recommended by the Department of the Environment. Samples from Ieachate insemi-trailes showed that the average COD, BOD, TDSandPHofthe materials in these stations were 16744,27522, 685.11 mg/lit respectively, With aPH ofS:S"which all are more than the standard limitations for sewages. According to this research, 98% of stations lack systems of collecting leachate

Landfilling IS an ultimate fate of any municipal solid waste management system, and it is a no alternative choice for disposal of municipal solid waste. The major environmental concerns associated with landfilling of wastes are related to the leachate generation and eventual discharge of leachate into the environment. Leachate quality is formed due to aerobic and anaerobic processes taking place in landfill. During aerobic decomposition of wastes, which is short in period, organic matters are converted to CO2, H20 and volatile acids. Anaerobic decompositon of wastes takes place in three phases, and methane, carbon dioxid, ammonia, and hydrogen sulfide gases are generated. In order to prevent leachate from percolation to ground water, natural or synthetic liners must be constructed at the bottom of landfill. Babol municipal landfill is located in Angelsi region, 30 km southwest of Babol with general slope of 14%. The total area of this site is 4 hectare. Yearly average municipal soild waste generation of Babol is 136 mertic tonne. So the life time of this site is estimated to be 4 years. Generation rate of primary leachate in this landfill is about 11.8m3 per day, for waste field capacity of 0.6 cm/cm and moisture content of 70%. Steress due to vehicle is negligible (0.001492 kg/cm). Leachate management system In Bobal municipal landfill is composed of three elements leachate trench with low permeability of K=10 cm/sec, comprised of sand with 16-32 mm in diametere and depth of 30cm. Thus 10500m3 of sand is used to construct these trenches in 3.5 ha of use full area available for landfilling. Leachate collection system is made of cement pipes with 15 cm in dimeter. These pipes are especially prepared for this purpose. And finally a liner made of local clay compacted in thickness of one meter, so the maximum conductivity of this liner was in the order of mangitude of 10 cm/sec.

The concentrations of cadmium, nickel, lead, and zinc in the four commercial species; Silver pomfret(Pampus argenteus), King mackerel. (Sc0l1l,beromorous commerson), (pomaclasys kaakan), and Green tiger Prawns (penaeus semisulcatus) were determined in the Persian Gulf all were collected from the Bushir coast. The samples were digested by ultrapure. nitric acid, and then analyzed using the atomic absorption spectrophotometry technique. The results show that samples contain 0.4 to 4.45, ?g/g dry weight for Cd, 1.3 to 157.1, ?g/gdry weight for ni 1.9 to 37.25, ?g/g dry weight for Pb, and 39 to 180.25, ?g/ gdry weight for Zn. Significant difference were seen between mean ofconcentrations of Cd, Ni,and Zn green tiger prawns (penaeus semisulcatus) with other species

Structural characteristics and spatial distribution of major farming systems in mountain environment of the Iranian Plateau as well as their developments in the past few decades have been studied by statistical analysis. Using this new approach, towards the study of natural resource allocation methods in mountains of Iran, the following resulted: Land and resource use practices have followed a market supplydemande policy based on the short term benefits of inhabitants of the capital city in the adjacent plain. Land and resource degradations have been much less than expected because of major emmigrations of inhabitants to the plain; Tehran. This is a temporary situation masking the effects of the existing lack Of resource use planning and management in this area. Inter-relations existing; between farming and animal husbandry (allocation of land and natural vegetation), practices within mountain farming systems and mountain-plain inter-dependencies existing in the regional economy, demonstrate the necessity of an integrated approaches in management of mountain resource allocation and farming system analysis. According to the results obtained, it is clear that agricultural planning and management (farming system; cropping coices and pattern) in mountain should take into account demands of for rage and pasture for animal production activities (farmer's major source of income). Proper in frastruture and supply of services for a well planned rural development (site selection) seem to be another major consideration for a sustainable rural development. Finally taking advantage of the existing advantages of mountains compared to plains, by a proper human settlement strategy is another major consideration in planning and development of mountainous regions.