Study of five years nitrite and nitrate content trends of Zanjan groundwater resources using GIS from 2006 to 2010

Nitrite and nitrate ions are considered part of the natural cycle of nitrogen. Concentrations over the standards endanger human health, therefore determination of groundwater nitrite and nitrate contamination, using a new technology is necessary. The purpose of this study was to compile, map, and evaluate patterns of nitrite and nitrate occurrence in Zanjan groundwater during 2006 to 2010. This cross-sectional study was investigated on Zanjan drinking water wells. Groundwater samples were taken directly from 72 wells. Nitrite and nitrate content of samples identified. Geographic information systems, ArcGIS and IDRISI, were used to map and evaluate the data and also analysis the nitrite and nitrate content trends. The results of this study showed that only a well had nitrate concentration above the standard and other wells were acceptable in nitrite and nitrate concentrations. The data showed falling and rising trend in nitrite and nitrate concentrations, respectively. Whereas the sewer system and wastewater treatment plant in Zanjan is not yet fully implemented, and traditional method of wastewater disposal is using absorption wells, hence, it can be contamination sources in the water.