Journal of Environmental Studies
Year:2000 | Volume:26 | Issue:25|Papers Count:10

The concentration of pollutants around tall buildings can be influenced by many factors such as down wind effects, waves, airflow due to free convection of heat transfer, building height etc. The main objective of this research was the investigation of the variation of pollutants concentration at different heights around tall buildings. Research was carried out measuring parameters such as Co or particle concentration around tall buildings. This study provided the behavior pattern of air pollution concentration variation at different heights. A comparison was made with a theoretical convection model to verify the trend of experimental results.

Several physical, chemical, biological methods and combination of them are used for domestic wastewater nitrogen and phosphrous removal. In this study, subsurface horizontal constructed wetland with length of 13-6 m, width of 10 m and depth of 0.55 m with Phargmites australis is used. Soil porosity was 40 percent. The system irrigated with domestic wastewater. The wastewater COD, TN, TKN and PO4 concentration was 300, 45-57 and 45-92 mg /l respectively. Hydraulic loading increased from 5 cm / day to 7.2 cm /d while detention time decreased from 4.2 days to 3 days. Removal percent of COD, TN, TKN and PO4 = at hydraulic loading equal to 5 cm / d and detention time of 4.2 days was 90, 83, 94 and 92 percent respectively. The study also indicates that removal percent of COD / TN / TKN and PO4 = at loading of 7.2 cm/day was 93, 8, 86 and 73 respectively.

About 700000 m3 of waste water is produced from Zirab coal washery plant every year. This black water not only carries about 4000 tons fine coals, It also contains waste water pollution. In this investigation by flocculation studies under optimized conditions (like concentration of flocculant, 0.0015 g/t , pH=8, concentration of silicate 0.01 g/t as depressant, and r.p.m of 150) has been shown that it is possible to separate solid particles from black water with recovery of 93% with ash removal of 40% at the same time. So, the water produced can be recycled to the washery plant with improved quality.    

The native fishes of springs, Ghanats and Caves of Iran are uniquely significant, since they are rear and, because of pollution, dryness, purposeful of or accidental introduction of exotic species and over all, because of industrialization are in danger. The stock of valuable fishes of Iran are declining while they have not been completely identified. The stock of these fishes, particularly those of economic value, such as large Barbus sp. at western part of Iran are declining. In an atempet fishes among the 140 station and average of three unit of effort for catch of fish in every station (total of 400 unit of effort) about 80 specimen of large Barbus were caught. Fishes were caught by electroshoker and various kind of net with mesh size of 2 cm to 4 cm. The Gamasib River was known to have large Carp, but this result showed that nowadays the stock of large Barbus substantially damaged. The stock of: B. subquincunciatus and B. grypus severely damaged. The purpose of this paper is to describe those factors, which affect the stock and abundance of Iranian freshwater fishes, and to suggest measures for the conservation of this fauna.  These factors include pre – industrial, and such factors related to industrialization and population increases as devegetation, water abstraction, fishing, pollution and faunal introductions. Introduction of new species to increase fish production and exploit the fishery potential of waterbodies, can be great utility; but has many hazardous impacts on native species, Biodiversity and Ecology of the Waterbodies. Some aspect of theses impacts are outlined.

Determination of water efficiency and resistance to drought in range plants are important factors that have essential role in selection of range development methods. As there is not any comprehensive study in resistance to drought, present research was done with selection of two range species. Selected species were two kinds of Gramineae, namely Dactylis glomerata and Eragrostis curvula. Some parameters such as used water, length, width and number of leaves, dry mass of leaves were studied. Obtained results showed that length and width of leaves were not under stress in irrigation periods, but number of laves, dry mass of leaf and stem decreased under drought stress. Amount of decrease in Er.cu was less than Da. gl. Increment of irrigation periods, increased root growth rather than stem, but root growth in Da. gl. Species has less water requirement and higher water usage efficiency in terms of amount of water usage. In terms of resistance to drought, Er. Cu has more resistance rather than Da. gl. Because of high water potential and lower witting point.    

In some rural areas in Kermanshah and Kurdistan provinces in western part of Iran, vegetation covers, in and around commentaries, are left intact. A plant ecology survey was carried out in seventeen of such sacred groves. Density, cover and dominance for each tree species was determined and the ecological values were calculated using Curtis method (1976). Results obtained from this study indicate that various aspects of vegetation structure such as species composition, growth form and canopy stratification are under strong influence of the long term conservation and other factors such as edge effect and chance extinction relating to grove size. These results, compared with similar information available on natural oak forests in the Zagros Region in Kemanshah province, indicate that sacred groves are more abundant, less diverse, have lost some of their life forms such as bushes and grass communities, have less complex cover strata and suffer from an unbalanced and aged age structure. These study shows that despite people efforts these natural – cultural heritage have no secure future and may be damaged by the same factors that destroyed oak forest in Zagros Region. Soil erosion, trampling, overgrazing and limitations by grove size on plant reproduction are imposing sever barriers to community regeneration in some of the sacred groves.

In this research common methods of ecological capability evaluation of forests were reviewed and limitations for performance were analysed. Ecological capability of forests is an index that show site potential in several role of wood production, soil conservation, flood control, biodiversity, conservation and water supply. This index is related to ecological capability evaluation must be chosen according to the objective of forestry. Common methods for ecological capability evaluation include plant and animal diversity, site index curve, soil and landform, interbranches, index plants, leave analyses, analyses regeneration and ecological mapping.  

In this research, the extensive lowland of the Khuzistan in SW. Iran has been studied floristically. Brief information on climatic, topograghic and lithologic aspects of the area are presented. Plants encountered in the area, based on collecting 1300 specimens are listed using the alphabetic system. The oil field areas, SW. Iran comprise three habitats: salt deserts and saline coasts, dunes and sandy soils, and finally marls, gypseous and calcareous places. Altogether 531 species from 351 genera belonging to 81 families were recognized in the study areas. For each species it’s collecting places and habitat, life-form and phytogeographical region is cited.