Nitrate contamination of groundwater and assessment potential and sources of pollution in the Evan plain

 Assessing pollution potential and amount of nitrate contamination in Evan plain as results of husbandry and fertilizer applications is of great importance for this plain. In this study، 16 wells and several surface water sources were sampled. Nitrate concentrations in these samples were analyzed and were compared to drinking water standards proposed by EPA. The results indicated that most amounts of Nitrate can be found at north part of Evan plain that generally are less than 37 mg/lit. To assess the source of groundwater NO3، the NO3/Cl and NO3/K charts were used. High NO3 concentration and low Cl concentration in the samples from north of Evan plain groundwater was related to leaching of chemical fertilizers to groundwater. Spatial distribution of nitrate concentration confirmed the output of both GOD and AVI models where they predicted maximum NO3 concentration at north part of the Evan plain.