Health risk assessment of nitrate pollutant in purified water for recycling in residential settlements

Groundwater is one of the sources used for drinking water.Nowdays, the amount of nitrate in most of the industrial effluents is outside the standard limit, and during the purification process, the efficiency of its removal should be carefully considered.Because, the infiltration of indaustrial wastewater into underground water, is unavoidable. In this study, it was conducted with the aim of investigating the health risk of nitrates present in the treatment of underground water extracted in the vicinity of one of the oil facilities located in the city of Tehran for reuse in a residential area. In order to assess the risk of purified water, the amount of nitrate output was sampled once every two weeks for a year and finally 25 samples were analyzed. The average measured nitrate concentration in the samples is equal to 3/63 mg/liter and the maximum measured concentration is equal to 7/134 mg/liter. Nitrate risk assessment method is selected based on EPA standard. The results showed that the level of non-cancerous risk in 84% of the samples for babies was above one (HQ ≥ 1) and consumption of this water can be dangerous for them. As a result, more sensitivity should be considered on the efficiency of nitrate removal in the treatment plant system.