Evaluation of Vulnerability of the Nitrate Pollution in Aquifer of Hamedan-Bahar

Point and non-point Pollutions (agricultural and urban) are among the major reasons of the decrease of the groundwater quality.The aim of this study was the assessment of nitrate pollution and usage management of irrigation and drinking water in forbidden Hamedan- Bahar plain. In this study 69 data of Nitrate pollution levels were evaluated with ArcGIS software then the amount of Nitrate pollutionand also the pollution of drinking water were compared with California and EPA standards, respectively, during two periods, before and after the growing season, in 1389. According to the results, the average of Nitrate during May and September were12.14 and 15.13 mg/litter of nitrogen ions, respectively. The plain area percentage that had the Nitrate concentrations between 5 to 30 mg/litterwere 99.17 and 96.24 during June and September, respectively. Comparing with California standard, the results indicated the moderate contamination of irrigation water. The highest level of DO in September was 17.2 mg/l and in June on the same place was 2.28 mg/l. Also in September the area that located in the range of5 - 10 mg/lhad 4.81 percent of the plain. The most contaminated section scontainedyekn- Abad village, the suburb of Hamedan and parts of the Central Plains due to excessive use of fertilizer, transfer of sewage and industrial centres. According to California standard the pollution of irrigation water was in the moderate range and according to EPA standard the drinking water was in the hazard range.