Hydrochemical appraisal of fluoride contamination in groundwater and human health risk assessment at Isa Khel, Punjab, Pakistan

Fluoride contamination in the groundwater of Pakistan is widespread with serious potential health consequences. We determine the groundwater of Isa Khel Tehsil upper Indus plain for drinking purposes and fluoride contamination by collecting 236 water samples from the water supply schemes supplied with groundwater. Results show that the majority of the parameters exceed the standard concentration of potable water. The concentration of fluoride ranges from 0.02 to 5.35 mg/L with an average of 1.8 mg/L, and about 58.5% of the collected samples have higher fluoride concentration than the allowed limit for drinking purposes. Fluoride pollution index results show that about 48.73% of samples have a high level of risk, 41.95% samples of the study area have medium level and only 9.32% of the water samples show low level of fluoride contamination. The health risk assessment due to fluoride contamination was computed based on chronic daily intake (CDI) and hazard quotient (HQ). For adult’s variation in CDI and HQ ranges from 0.001–0.15 mg/kg/day and 0.001–2.55 respectively whereas in children it ranges from 0.001–0.29 mg/kg/day and 0.02–4.84. Health risk assessment parameters indicate that in the case of adults, about 40.25% of samples exceeded the maximum allowed value of hazard quotient i.e., HQ > 1, while for children, about 66.95% of samples have HQ > 1, which means that children are at higher risk than adults because of higher vulnerability to fluoride contamination in drinking water. Thus, there is a need for effective groundwater monitoring and management in the study region to safeguard residents from various illnesses associated with drinking water with varying fluoride concentrations.