مجله محیط زیست و مهندسی آب
سال دوم شماره 4 (زمستان 1395)

Water pollution in recent decades is as serious threat to the human and natural ecosystem so that assessing changes water quality are one of the most important topics for desirable use . In this investigation has been studied the Azna river quality in Chamzaman Hydrometric station that used for dry period (April to September) and wet period (October to March).To evaluate the water quality were used the Piper, Schoeller, Wilcox and time-series diagrams. Results water river Azna in Piper diagram indicative water type is calcic bicarbonates. In studied river, according to the graph Schuler is evaluated good and desirable for drinking. According to statistical studies, the methods of data analysis led to be determined 11 principal components for the data set, the first three components with more than 70% variability, statistical population interpret. Also according to the graph plotted cluster the samples is plotted in four clusters contains: the first cluster SO4-2 and pH, second cluster K,third cluster Ca2 and in the fourth cluster TDS, EC, Cl-, Mg2, HCO3-, Na and TH. The highest correlation between the total dissolved solid and chloride is observed. According to meaningful level of 0/05 in Kolmogorov – Smirnov, all ions of Azna River have normal distribution. Linear regression analysis of cations, anions and electrical conductivity as the dependent variableversus of total dissolved solids as the independent variable show high correlation between TDS with EC and Cl.

Because of scarcity of surface water, consideration of water quality is a very important issue in Iran. Surface water quality monitoring and assessment is very expensive and time consuming; Therefore, finding a cheap, simple, and relatively exact method which can predict water quality would be very useful. In this study, Water Quality Index was used for measuring water quality. In order to monitor surface water quality and calculating the water quality, the data of six quality survey stations in SofiChay watershed during the period 1972-2012 were used. To determine the influencing parameter on the surface water quality within the watershed, the Shannon weight entropy method was used. Based on the amount of Shanon entropy and the calculated entropy weight, the effective parameter was evaluated in six stations: Tazekand, khormazard, Esfestanaj, Kahlikdarasi, Maragheh, and Khekan. The results indicated influencing parameters at the stations studied are pH, Mg, TDS, EC, and HCO3 respectively. Calculating the water quality index through using Shannon entropy indicated excellent quality of surface waters of the study area.

Estimation of scour depth and understanding the flow field around pier would help to design with safer factor. In this study, we used the numerical model SSIIM as a CFD model to simulate flow and scour pattern simultaneously around single pier. The model was verified using laboratory data including the results reported for single pier. In this model, we considered the as a turbulence model to solve the 3D Navier-Stokes flow equations and used their outputs as inputs of sediment transition equations. Comparison between scour calculations of SSIIM model and experimental terms showed that the model has appropriate deviation value for estimating the maximum scour depth around single pier. Numerical and graphics discussions of scour pattern and flow field have been done in various simulation time for pier. Graphical results showed that the down flow at front of pier and upward flow at the rear of pier. In addition, the maximum down flow was simulated with high accuracy in compare with experimental results.

Time series analyses is a base method for more decisions about hydrological process and water operation. In Iran, drought is a continues and normal condition happening frequently and can be predicted by statistical and mathematical methods and models. In this research, meteorological drought was analyzed in 5 stations of Salmas region (Nazarabad, Salmas, Yalgozagaj, Chahrygeolya and Urban) located in West Azarbijan Province, Iran. For this purpose, the monthly rainfall time series, 30 years lengths (1979-2008) for these stations were simulated by times series models as: AR, MA, ARMA and ARIMA. Then the best model was used for forecasting the drought. Then the monthly rainfalls were predicted for next 7 years using the chosen model. In the following, the intensity of droughts was calculated by standard precipitation index (SPI). The final model chosen for the stations of Nazarabad, Salmas, Yalgozagaj, Chahrygeolya and Urban were the ARMA(1,1), ARMA(3,2), ARMA(1,1), ARMA(2,3) and ARMA(4,2) models, respectively. The results showed that for 30 years (1978-2008), drought had increasing trend just in Nazarabad station, while in other stations such as Salmas, Yalgozagaj, Chahrygeolya had decreasing trend.

In this study, groundwater of Ardabil aquifer quality in terms of drinking and agricultural, was evaluated. For this purpose, 76 wells including 32 drinking wells and 44 agricultural wells were considered. The results indicated that groundwater quality on the Water Quality Index (WQI) is in good condition. Based on the standards of the World Health Organization (WHO) and Institute of Standard and Industrial Research of Iran (ISIRI), 10.5 percent of the wells have nitrate levels above the limit in the wet season; but in the dry season, about 29 percent of the wells had nitrate values higher than allowable level. In order to assess the quality of groundwater for agricultural use, as well as the Wilcox diagram and other parameters of sedimentation and corrosion including: Langelier saturation index (LSI), Ryznar Index (RSI) and Puckorius (POR), magnesium hazard (MH), permeability (I), the remaining sodium percentage (RSC), sodium adsorption ratio (SAR) and the percentage of sodium and chlorine were used. The results showed groundwater of this aquifer are corrosive and use it in urban water supply systems, causing illness and various problems caused by corrosion of pipes and the, the human will. The use of these waters, for agricultural purposes will cause problems in metal fittings of sprinkler irrigation systems.

This study was performed to evaluate the effect of soil physicochemical characteristics on the gully expansion in the Darrehshahr Township of Ilam Province, Iran. In this regard, 36 gullies were selected. The soil physicochemical properties and geometry characteristics of gullies were tested using aerial photography, the digital maps, and field operations. The multiple regression was used to determine the impact of these factors on each gully geometry characteristics and to establish relationship between dependent and independent variables. The results showed that EC, SAR, and Na have the highest impact and play the most important role in the development of gully. Whereas amount of organic matter and total of Caﯣ⃻ prevent gully development because of their soil adherence and flocculating nature. Moreover, based on the cross-section development model, the amount of SAR and the Na had the highest impact in the increasing cross section of gully. However, the amount of gypsum and total of Ca and Mg play the most important role in control and prevent of the gully development.

In the past decade, remote sensing has been widely used to identify surface changes of different vegetation and their classification. Increasing the level of Canebrake of the Zarivar Lake and its risks for aquatic organisms living in the lake has become one of the most important issues in recent years. Therefore, the aim of this study was to identify surface changes of this Canebrake in the past three decades using Landsat TM and ETM. For this purpose, bands 3, 4, and 5 of images were geo-referenced. RMSE were less than one pixel for all bands. The supervised classification method with a maximum likelihood algorithm was also applied to detect the changes of water area on the combined images (bands 5, 4, and 3) of months with full water in the lake. NDVI index was utilized to identify the surface changes of Canebrake on the images taken in the months with low water in the lake. The results show that the rise and fall of water area and surrounding canebrake has a direct correlation with a rainfall and increase in both levels maybe occur at the same time. Study on the coastal strip of water area with GPS and combined images showed that the coastal line had not a significant change in the past three decades.

Food contamination with aflatoxins, a secondary metabolite produced by filamentous fungi, is a fundamental subject in food safety for human. Therefore, especial attention should be dedicated about contamination of animal feed and transfer to human food chain by contaminated livestock products. The promising approach for controlling aflatoxins in food is prevention of fungi growth. However, practically this method is not successful; therefore, alternative techniques are needed to eliminate these toxins from consumed products in human and animals. In present study, four phrases used as key words were “aflatoxin, reducing methods, food and feed “by databases including Elsevier, Scopus, PubMed, and Google Scholar. After reviewing 83 articles, 59 studies were selected; these papers were published between 1960 -2014 for recent review. Therefore, it was decided to collect and review the common and usual methods for decreasing or deletion of deterioration of Aflatoxin in livestock feed and human food including physical, chemical and biological methods.