Spatial Distribution and Health Risk Assessment of Nitrate in Drinking Water: A Case Study in the Central Plateau of Iran

Introduction: This study aimed to determine nitrate levels in water wells supplying drinking water in Taft city, Iran, and assess the associated health risks using the method proposed by the US Environmental Protection Agency. Materials and Methods: In 2021, the average annual nitrate levels were determined in 48 drinking water wells which were located in Zone 39 (Taft city). Health risk assessment and sensitivity analysis were conducted to identify the most influential variables.  Results: The mean nitrate content in  the water wells under study was 32.88 ± 18 mg/L. Out of the 48 examined water wells, 10 had nitrate levels higher than the standard value (50 mg/L) established by the Iranian Institute of Standardization (Standard No. 1053) and WHO. The calculated Hazard Quotient (HQ) for children and adolescents was greater than 1, while it was less than 1 for adults. Nitrate concentration in drinking water was found to be the most important influencing variable in the calculated HQ for children and adolescents. Conclusion: The results indicated that children and adolescents’ health in the studied area is at risk, and appropriate measures must be implemented to avoid and control the exposure of these vulnerable groups; they can be continuous monitoring of nitrate levels using on-site treatment methods where nitrate concentrations exceed the standard level, and decommissioning wells with high nitrate levels.