Iranian Journal of

Background and Objectives: Dez dam located on Karun River is one of the largest Iranian dams. In a field study, EC, NO₃, NH₄, PO₄, turbidity, TS, alkalinity, coli, temperature, chlorophyll a, DO, BOD₅, and Secchi disk (at depths of 0, 2.5, 5, 10, 25, and 50 m)were measured at five sampling points during 2011-2012 water year. Materials and Methods: Water Quality Index and TSI were calculated for all sampling points and quality zonation was conducted in GIS. Results: It was found that the best water quality index for reservoir water is at second sampling point with amount of 61 situated at the center of reservoir, and the worst index is at entering point to the reservoir with amount of 46 in April. The main reason of changes was turnover of thermal stratification. Conclusion: The laboratory analysis and assessing the quality indices revealed that the Dez reservoir water is suitable for variety of public uses, however, it needs advanced treatment for drinking purpose. Moreover, in the case of continuity of pollutant entrance into the reservoir, the eutrophication risk would threaten the reservoir water quality. Eutrophication occurrence will cause serious limitations in water use applicability, increase turbidity, produce toxic materials, and increase sedimentation regime.

Background and Objectives: Street dust reflects one of the most important indicators of pollution in the urban environment. Most studies carried out in the world on heavy metal pollution are related to cities and metropolitans, while less attention has been paid to towns. Masjed-e- Soleiman, the most oil-rich town is located in the north eastern part of Khuzestan Province in Iran. This town contains geogenic pollutants such as gas and oil sources, oil and gas activities, oil and gas combustion, industries, and heavy traffic, which make it important from the viewpoint of environmental impact assessment.

Materials and Methods: For monitoring and management of pollution, 11 samples of street dust were collected and prepared from different stations within the town during the dry season (June 2013). Each sample was analyzed using ICP-OES instrument.

Results: Possible sources of the heavy metals were identified by multivariate analyses such as Principal Component Analysis (PCA) and Cluster Analysis (CA). In addition, factors such as the Index of Geo-accumulation (Igeo), Pollution Index (PI), Integration Pollution Index (IPI), and Enrichment Factor (EF) were assessed to determine the degree of heavy metals pollution in street dust of the Masjed-e- Soleiman Town. The results of PCA and CA indicated that the region is mostly affected by oil pollution (both natural and combustion of fossil fuels), traffic, and industrial activities (PI revealed high levels of Pb, Cd, Cu, and Zn pollution in samples and the average level of Ni, As, and V pollution in other samples). Igeo indicated the moderate to severe pollution of some samples to Pb, Cd, Cu, and Zn while no to moderate pollution against Ni, As, and V in other samples. EF for Pb, Cd, Cu, and Zn showed a significant pollution in some samples and other samples represented the least pollution against Ni, As, and V.

Conclusion: Results showed that the concentrations of heavy metals in dust samples were higher than control samples in Masjed-e- Soleiman. Thus, the classification of pollution in street dust in Masjed-e- Soleiman is as follows: IPI> EF> Igeo ≈ PI.