نشریه زمین شناسی محیط زیست
پیاپی 48 (پاییز 1398)

Riverin sediments of the Dohezar River in Tonekabon contain high levels of heavy metals and therefore, they were chemically analyzed to determine concentrations of these elements. In fact, this research intended to evaluate the ecological risks of the heavy metals As, Pb, Cr, Zn, and Cu in the river sediments. Contamination indices such as enrichment factor and contamination factor, were evaluated. Considering the average concentrations of the heavy metals at all of the Stations, the maximum average for the elements was zinc and the minimum was copper. Therefore, the averages of changes in the concentrations of the elements are Zn > Cr > Pb > As > Cu. Considering calculation of the enrichment factors for the heavy metals according to the EF classification table, the maximum number of Stations (43.02%) with respect to contamination with As were in class 4(moderately severe enrichment). With respect to enrichment of Pb, Zn, Cr, and copper, the rest of the stations with 83.72, 77.91, 86.05, and 69.77%, respectively, were in class 2 (minor enrichment). Considering the high concentrations of the studied elements in the sediments of the region compared to the background value, and based on calculations related to contamination factor, arsenic with the average of 11.9 exceeded the most from the standard limit. It was followed by Pb with 2.2, zinc with 2, Cr with 1.8, and Cu with1.6 (copper exceeding the least from the standard limit). This research used statistical studies on correlation coefficients and cluster analysis to find the origin of the heavy metals in the sediments of the region. The low correlation between the heavy metals in the soil can indicate they probably did not have the same source. Moreover, these elements have different geochemical behaviors due to their low correlation.

Major Dam construction projects have increased due to the widespread climate change, because of increased drought, human population growth and, consequently, increased global demand for energy and water. However, without comprehensive research, a large project such as a dam will have an irreversible and unpredictable impact on the environment. A survey on the history of dam construction projects shows that many of them have been designed and exploited regardless of environmental considerations, thus causing various contamination and destruction of major parts of natural resources have been. In this research, the environmental impacts of the Eyvashan earth dam were identified in two phases of construction and exploitation on biological, physical-chemical, economic-social, cultural and strategic environments, using Leopold modified matrix and rapid impact assessment matrix (RIAM). The results showed that the most negative and negative effects in the construction phases and exploitation in the modified Leopold matrix and the Rapid Impact Assessment matrix related to the physical-chemical environment. In addition, the most positive effects in construction and exploitation phases for the modified Leopold matrix are related to the strategic and socio-economic environments and for the matrix of the assessment of the Rapid Impact Assessment of the socioeconomic environment on both phases. The results show a very good fit between the two matrices and confirm the accuracy of the results in the environmental assessment of the Eyvashan Dam in two stages of construction and exploitation.

Water resources management, especially groundwater, is particularly important in arid and semi-arid regions. Various natural and anthropogenic factors, especially in recent decades, have caused critical conditions and groundwater levels in most parts of the country, including Kurdistan province. Therefore, the study of groundwater level drop in Qorveh plain, which is one of the most essential and most extensive plains in the area, is of great interest. It placed. To carry out this study, the statistics of 28 observation wells over two 5-year periods (88-88 and 88-92) studied. Initially, statistical data were collected, and after data entry into Geographic Information System (GIS), interpolation methods, maps of co-potential lines, and groundwater loss zoning prepared. Water level hydrographs also plotted in the Excel software environment. The results obtained from the overlap maps showed that the highest groundwater level in the second 5 years in the western part of the aquifer was 5.75 meters and in the first five years in the eastern parts was 2.15 meters. Groundwater level hydrographs show that during the ten years, the water level in the Qorveh plain was 10.84 meters, which averaged 1.08 meters per year.

This research has examined the changes that have been made as a result of accumulating the Isfahan subway tunnel excavated soils in the Zeinel area (at the east of Isfahan). The samples of the tunnel fresh excavated soils, of the accumulated soils, and of the natural soils in disposal area were taken, randomly. All the samples were sieved and to determine the percentage of drilling foam material, organic carbon percentage of some of them were analised. Elevation and geographic location of the sampling sites were also determined. the directions and speeds of strong winds that have blown in the east of Isfahan was obtained and ranked. Comparison of the granulometry analysis results of the mentioned soils showed that there are great differences between the mentioned criteria of the freshly excavated soils with natural soils and there are afew diffrences between the mentioned criteria of the accumulated soils with natural soils. These differences increase the permeability in the region and reduce the balance between the morphogenic-pedogenic processes.The topographic findings show that mainly accumulating soils in the region have somehow changed the topography of the area that will cause disruption the balance between the morphogenic and pedogenic processes and increase morphogenic processes. Also, the strong winds don't blow toward Isfahan, consequently the environmental hazards will not be created

In recent years, the excessive use of existing water resources and subsequent droughts, have led irrigation water resources quantitatively and qualitatively changes. Water quality is one of the most important determinants for its use in various water uses. Therefore water quality management and monitor are important. In this study, the water resources quality of Siuki area of Torbat-Heydarieh city was investigated according to the water resources chemical analysis used in agricultural sector consist of sugar factory wastewater, refined urban wastewater, Qanat and well (a total of 10 wells with crop use) during 2009-2013 years and Wilcox diagram, permeability index (I), SAR, chorine and sodium percentage and other cations and anions were studied. The results showed that the salinity of the wastewater was equal to 20000 mmhos/cm and in the (C4) class. According to the Wilcox and SAR, most of the samples were in C4S1 and in the middleclass. Based on the results, all of the water resources, both conventional and unconventional of the studied area are suitable for agricultural uses, but for the plant wastewater, more should be taken for agricultural and crop production.

This study examines the environmental, economic, and social impacts of mines on local communities. Impact assessment in these three areas (environmental, social and economic) predicts the potential environmental factors resulting from the implementation of development projects, some of the ways to reduce or eliminate these unacceptable and unintended, it makes predictions and presents predictions to decision-makers. In this study, a reasonable decision can be made by understanding the impact of each of the above factors on the continuation or stopping of mining activity.  By preparing a questionnaire on gathering the required information and compiling a questionnaire in three axes, economic, social and environmental, a total of 32 questions were put on the gathering of opinions from the expert community. Then, the reliability of the questionnaires was assessed by SPSS software and then, a cost-benefit analysis was performed on the status of the proposed sand mines. After implementing the model presented in three axes, economic, environmental and social, the results of the costs were 0%, 53.27%, and 52.67%, respectively, and the income results were 100%, 46.73%, respectively. % 47.33% was obtained. Therefore, the income from the activities under study is dominated by the costs considered in the three axes considered.