An interpolation technique, ordinary Inverse distance Weighted (IDW), was used to obtain the spatial distribution of groundwater quality parameters in Damghan plain of Iran. According to Scofield guidelines for TDS value, 60% of the water samples were harmful for irrigation purposes. Regarding to EC parameter, more than 60% of studied area was laid in bad range for irrigation purposes. The most dominant anion was Cl- and 10% of water samples showed a very hazardous class. According to Doneen guidelines for chloride value, 100% of collected water from the aquifer had slight to moderate problems for irrigation water purposes. The predominant cations in Damghan plain aquifer were according to Na+>Ca++>Mg++> K+. Sodium ion was the dominant cation and regarding to Na+ content guidelines, almost all groundwater samples had problem for foliar application. Calcium ion distribution was within usual range. The magnesium ion concentration is generally lower than sodium and calcium. The majority of the samples showed Mg++amount within usual range. Also K+ value ranged from 0.1 to 0.23 meq/L and all the water samples had potassium values within the permissible limit. Based on SAR criterion 80% of collected water had slight to moderate problems. The SSP values were found from 2.87 to 6.87% According to SAR value, thirty percent of ground water samples were doubtful class. The estimated amounts of RSC were ranged from 0.4-2 and based on RSC criterion, twenty percent of groundwater samples had slight to moderate problems.

Introduction: Estimating air pollution levels in areas with no measurements is a major concern in health-related studies. Therefore, the aim of this study was to investigate the amount of exposure to particulate matter below 2. 5 μ (PM2. 5) in the metropolis of Tehran. Materials and methods: The hourly concentrations of PM2. 5 during 2017-2018 period were acquired from the Department of Environment (DOE) and Air Quality Control Company of Tehran (AQCC). The hourly concentrations were validated and 24-h concentrations were calculated. Inverse distance weighting (IDW), Universal Kriging, and Ordinary Kriging were used to spatially model the PM2. 5 over Tehran metropolis area. Root Mean Square Error (RMSE) and Mean Error (ME) were used to measure and control for the accuracy of the methods. Results: The results of this study showed that RMSE and MENA values in Kriging method was less than the IDW, which indicates that the Kriging was the best method to estimate PM2. 5 concentrations. According to the final map, the highest annual concentrations of PM2. 5 were observed in the southern and southwestern areas of Tehran (districts 10, 15, 16, 17, and 18). The lowest exposure to PM2. 5 was found to be in districts 1, 2, 3, 6, and 8. Conclusion: It can be concluded that Kriging method can predict spatial variations of PM2. 5 more accurately than IDW method.

Introduction: Water conflict is a major challenge that, if left unmanaged, will become a security issue. Although tensions over water have increased, conflicts over shared water resources are more likely to happen. The study aimed to investigate water conflict and its management strategies among farmers. Methods: The descriptive-survey research method was used. The data-gathering tool was the questionnaire, which its validity was verified through face validity. The study population included farmers who used shared water wells to provide water for agriculture (N=478). Using Cochran's formula, the sample size was 214 farmers who were selected by the simple random sampling method. Data were analyzed using SPSS software. Findings: The results showed that “, drought”,and “, increasing number of farmers”, , with an average score of 3. 56 and 3. 45 respectively on a scale of 1 to 5, are considered as the main causes of agricultural water conflict. From the farmers’,view, the priority for reducing water conflicts was the participation of farmers in managing water wells and negotiating with farmers around the water. On a scale of 13 to 65 with an average of 38. 51, the perceived agricultural water conflict was at the medium level. By increasing farm distance from the well, area of agricultural rental land, and annual income from non-agricultural activities, the perception of agricultural water conflict increased. However, by increasing owned agricultural land area and agricultural income, the perception of agricultural water conflict decreased. The main strategy used by farmers to manage agricultural water conflict was “, control”, , in which coercion and force are used to manage conflict. The “, problemsolving”, and “, avoidance”,strategies were the second and third priorities respectively.