Articles in Press

Anthracene and phenanthrene belong to a group of persistent environmental contaminants called PAHs. Evaluation of the structure of two selected PAHs i.e. anthracene and phenanthrene on their resistance to destruction by UV-activated PDS was the aim of this study. The authors focused on two aspects of this problem: - the role of the so-called ‘bay-region’, in the structure of phenanthrene, during PDS/UV oxidation - formation of substituted forms of these PAHs in the absence and presence of three nitrogen-containing compounds i.e. ammonia and nitrite or nitrate ions. Even though phenanthrene and anthracene have the same molecular formula, the difference in their ring assessment influences their degradability. Considering all the results, in all the cases anthracene was degraded faster and/or had a higher degradation rate. That proves phenanthrene to be more stable and resistant for degradation however comparison of PDS/UV systems vs. UV– irradiation alone confirms that the addition of PDS accelerates the degradation of anthracene and phenanthrene. Comparison of PDS/UV with the addition of three different nitrogen-containing compounds showed a significant difference between anthracene and phenanthrene. In the experiments with phenanthrene were observed additional peaks with an absorption maximum between 230-240 cm-1 which is characteristic of the nitro-group. Based on their absorption maximum and the addition of nitrogen-containing compounds, emerging by-products are assumed to be nitro-derivatives of phenanthrene. The results of GC/MS analysis suggest the possibility of formation of many compounds which can be formed from phenanthrene and are embedded on its skeleton. These analyzes also suggest the rearrangement of phenanthrene’s aromatic rings and formation new compounds.

The large cities are facing with a phenomenon called high-rise buildings which is due to the increasing of the population and also developing the cities. One of the negative impacts of high-rise buildings is the change in urban wind flow. Air pollutions is a major problem in the cities and the wind play an important role in the dispersion of air pollutions. The most probable wind direction for Tehran is west and hence district twenty-two of Tehran municipality which is located in northwest of Tehran (Capital of Iran) is in the dominant direction of wind flow. This paper presents a numerical method to investigate the interaction between the wind flow, pollution and high-rise buildings in district twenty-two of Tehran municipality. The effect of these phenomenon on the other regions is considered as well. Computational fluid dynamics (CFD) by ANSYS Fluent software has been used in order to simulate the problem. The results of this study indicate the existing buildings and their layout had no effect on wind velocity and trapping the pollution and do not cause an increasing of the local concentration of pollutants. So the geometry and layout of buildings allow the flows and environmental pollutants to pass.

The Heihe River is the second longest inland river in China, which is one of the most important inland river basins in the northwest area. The effect of drought on ecological environment can be exacerbated by climate change. Eco-water diversion project was implemented since 2000 to solve the increasingly serious problem of ecological environment deterioration in the lower reaches of Heihe River Basin. In order to reveal whether the eco-water diversion project solve the ecological environment deterioration thoroughly, the change of hydrology and vegetation were investigated and compared by using the remote sensing data, field surveys, monitoring and statistics data. Our results showed that the soil water content, groundwater level and vegetation coverage increased after eco-water diversion, especially in 0-20cm, the value increased 30.05%, which results vegetation restoration in some area. However, the seasonal distribution of eco-water diversion is extremely uneven, 70% of the runoff is mainly concentrated in January to March, and September to October. Water was seriously insufficient in the critical water demand period of plants such as germination and fruit period due to river cutout. Moreover, some areas were degraded due to salinization. In addition, the extreme change of soil water is not conducive to plant growth, but will increase the waste of water resources due to the increasing of ineffective surface evaporation. It is difficult to improve the quantity of discharged water in the upper reaches of Heihe River, so the distribution time and mode is very important for stable and healthy development of vegetation in the downstream. Therefore, eco-water diversion project is not a simply measure to improve the ecological environment. We suggested that hydrological processes should be consistent with ecological processes in the lower reaches of Heihe River, otherwise, the most important significance of eco-water diversion project will be lost. Exploring this will be helpful in formulate scientific and reasonable water dispatching scheme, achieve water resources allocation and water demand matching, improve ecological benefits.