Probabilistic Human Risks of Fluoride and Nitrate: A Case Study of Municipal Drinking Water in Mosul, Iraq

Abstract

The present study aims to assess the probabilistic health risks to humans from fluoride and nitrate ions in the municipal drinking water supply of the Al-Shurta, Muhandiseen, and Al-Andalus neighborhoods on the left side of Mosul city. A total of 180 water samples, were collected from 30 sites between July 2023 to January 2024 for determination of nitrate and  fluoride. The chronic daily intake and risk quotient (Rf) were also calculated to evaluate the safety of the drinking water across various demographic groups, including (infants, children, adolescents, young adults, pregnant women in early stages, and elderly males and females). The study found that nitrate levels ranged from 2.923 ± 0.736 to 3.932 ± 1.406 mg/L, while fluoride levels varied between 0.357 ± 0.070 to 0.428 ± 0.071 mg/L. The nitrate pollution index (NPI) values did not exceed (0.612) the safe level, indicating that the water is free from nitrate contamination. Studied Rf values for nitrate and fluoride were within safe limits for all age groups. However, the highest Rf values for nitrate and fluoride were observed in 3-month-old children, (0.3682 and 0.0572) followed by infants and children aged from 3 months to 1 year. Adolescents less affected, while elderly females showed slightly higher vulnerability than their male counterparts. In general, these results indicate that there are no current potential health risks, and they constitute a scientific database for the competent authorities to make decisions and manage water resources for use in drinking water supplies.