Temporal distribution and zoning of nitrate and fluoride concentrations in Behbahan drinking water distribution network and health risk assessment by using sensitivity analysis and Monte Carlo simulation.

The present study aimed to investigate the spatial distribution and zoning of nitrate and fluoride concentrations in the drinking water distribution network of Behbahan city and the health risk caused by their concentration using sensitivity analysis and the Monte Carlo simulation during 2018 to 2019.In this cross-sectional study, 90 samples were collected from 45 points of the city's drinking water distribution network in the two high-rainy and low-rainy seasons.Nitrate and fluoride concentration was measured byDR 5000 spectrophotometer and its non-carcinogenic impacts were calculated using EDI and HQ.The results showed that the average nitrate concentrations in high and low rainy seasons in the study area were 15.05 and 13.35 mg l−1, respectively.Also, the average concentrations of fluoride in high and low-rainy seasons were 0.67 and 0.76 mg L−1, respectively.The fluoride concentration in the high-rainy season showed a decreasing trend from north to south.The nitrate concentration decreased from north to south and southwest.The amount of nitrate HQ in the age groups corresponding to children, adolescents, adults and infants were 0.5, 0.4, 0.34, and 0.07, respectively.The fluoride HQ levels in the age groups corresponding to children, adolescents, adults and infants were 0.7, 0.5, 0.05, and 0.1, respectively.These results showed that children were the significant at-risk group due to these ions.According to the Monte Carlo simulator, 95th percentile caused by exposure to nitrate and fluoride ions in all age groups was more than one.Based on the sensitivity analysis, the most efficient factor in the health risk caused by nitrate and fluoride ions was the concentration of these ions in the drinking water distribution network. [ABSTRACT FROM AUTHOR]