Investigation of Nitrate in surface water supply Taham dam Zanjan and zoning in winterand spring 2015

Rivers are a small fraction of the world's water resources and are as one of the main sources of water supply for a variety of uses including agriculture, industry and drinking. The aim of this study was to evaluate the measure of nitrate concentration in the entering surface water of Zanjan Taham dam and Zoning.
In this cross-sectional study, First 40 stations was found the base of entry contamination of points and feeder of branches in both of the rivers. Number of 160 samples of water were taken from Ghalharod and Taham rivers based on the time of fertilization and rain of season in during the two period of time winter 1393 and spring 1394 and test of samples was performed according to standard method guideline (4-123). Compare the results with national and international standards they were analyzed using SPSS16 and ArcView GIS 9.3 software. the distributions of concentrations were mapped in Geographic Information System and influential factors were investigated.
According to the results of this study, the concentration of nitrate was lower than WHO guideline and Iran's drinking water standards. Statistical analysis of results showed that there is not significant differences between nitrate concentration in the winter and spring seasons in the both rivers, but it was a significant difference between concentration of nitrate in the rivers. According to the obtained maps, the maximum nitrate concentration was observed in the 134, 151, and 169 locations.
Based on the obtained results, the main reasons for variation of nitrate concentration was related to unsanitary human sewage and animal waste disposal. The results of zoning of nitrate along with the rivers showed that by moving away from the source of contamination, concentration of pollutant reduced again. However, due to the self-purification power of the river, Water quality lower than standard.