Survey and Zoning of Nitrate Concentration in Groundwater Resources in Freidan Using Geographic Information System (GIS)

The high consumption of nitrogen-containing fertilizers in the agricultural lands of Freidan is resulted to increasing of the nitrate concentration in drinking water in some of the underground water wells even higher than allowed amount. Therefore, the aim of this study is survey and zoning of nitrate concentration in groundwater resources in Freidan using Geographic Information System (GIS). This study is analytical-cross sectional. In this research, nitrate concentration determination carried out by spectrophotometry according to standard method and compared with WHO guideline (50 mg/l). Then zoning of nitrate concentration in groundwater resources in Freidan was investigated using Arc GIS 10.1 by IDW and Kriging methods. Findings: The results of this study showed that in half of the wells in Freidan, nitrate concentration was higher than the WHO guideline. Also, nitrate concentration zoning using GIS in groundwater resources was showed that the wells including high nitrate were located in central and southern regions of Freidan. Improper irrigation methods and excessive use of nitrogen fertilizers by untrained farmers can increase nitrate in groundwater resources. So should consider arrangements for farmers Training related to reduction of these fertilizers consumption.