Health risk assessment of nitrate in drinking water in Shiraz using probabilistic and deterministic approaches and impact of water supply

•The nitrate concentration was higher in southeastern of the city.•Total means of nitrate concentration was lower than the standard.•The maximum of the hazard quotient belonged to infants.•The hazard quotient was higher than one for infants at 11 points. Increased nitrate concentration in water resources due to human activities and lack of wastewater management can affect consumers' health adversely. The objective of this study is health risk assessment of nitrate in distribution drinking water in Shiraz using probabilistic and deterministic approaches. Nitrate concentration was determined in 31 sampling sites of distribution system. N-carcinogenic human health risk as a consequence of the drinking contaminated water to nitrate was assessed in four age groups (less than 2, 2 to 6, 6 to 16, and more than 16 years). Also, health Hazard Quotient (HQ) and sensitivity analysis were investigated using the Monte Carlo simulation technique with a probabilistic approach. The lowest and highest two-year mean concentration were 2.1, 58.35 and the total two-year mean of nitrate concentration was 22.6 mg/l. Nitrate concentration was higher than standard level in grab sampling at some points. While the total mean of HQ was less than the adopted threshold in all age groups, the results showed that HQ at some sites is higher than adopted threshold level. The minimum and maximum of the HQ belonged to adults (0.22) and infants (0.8). The mean and the 90th percentile estimated HQ using probabilistic approach for infants, children, teenagers, and adults were (0.78, 1.66), (0.45, 0.0.95), (0.41, 0.86), and (0.23, 0.48), respectively. Sensitivity analysis indicated that concentration is the most effective parameter in HQ. Considering that the highest estimated HQ was related to infants and also increased nitrate concentration can have adverse health effects for this age group, it is suggested to apply management and control measures to reduce the nitrate concentration in groundwater resources with a high concentration of nitrate.