Sources of Nitrate and Bromide Contaminants in Groundwater of the Alluvial Aquifer of Arak, Iran

The present study investigated NO3- and Br- contamination in groundwater of Arak aquifer, Markazi province, Iran. Correlation and factor analyzes were used to detect interrelations and sources of NO3- and Br- ion concentration and other physicochemical variables. No correlation was observed between NO3- and others contents, but a positive correlation was identified between Brand other major variables such as EC, TDS, Cl- and SO42- in the groundwater. The results showed that groundwater samples of two areas of Arak aquifer were severely contaminated by NO3- (up to 50 mg/L) and Br- (up to 0.5mg/L), which exceeded the WHO and EU provisional guideline values. Nitrate showed an anthropogenic source that originated from sewage water from domestic and industrial activities. Bromide originated from palaeo-salty water of Mighan Lake with a geogenic source.