Human health risk assessment: Study of a population exposed to fluoride through groundwater of Agra city, India

Fluoride (F-), a harmful compound if present in high concentration, is typically found in groundwater. It is important to investigate the F- concentrations in groundwaters of areas where individuals use groundwater for drinking purposes. The objectives of this study were: (a) to estimate the F- exposure, and (b) to assess the non-carcinogenic risk through consumption of groundwater among urban population (different age groups) of Agra city. A total of 28 groundwater samples were collected from Agra city in May 2016, which comprised 22 samples from hand pump and 6 samples from tube wells from shallow aquifers at different sites. The F- concentrations varied from 0.90 to 4.12 mg/L with an average value of 1.88 mg/L. The results obtained reveal that about 64% of the samples exceeded the F- permissible limit of 1.5 mg/L. Nevertheless, 32% of the samples were well within the WHO drinking water guidelines and 3.5% of the samples from the groundwater were below the 1.0 mg/L threshold. The maximum estimated exposure doses were 0.69, 0.31 and 0.12 mg/kg/day for infants, children and adults, respectively. A dental fluorosis becomes evident when the results obtained are compared with an oral reference dose of 0.06 mg/kg/day. The hazard quotient (HQ) was found to be more than 1 for infants and children in all the studied areas which indicates that young consumers are more vulnerable to non-carcinogenic risk due to exposure of F-. On the other hand, the adults at about 71% of the sampled sites may be victims of non-carcinogenic risk. From the results obtained in this study, it is recommended that there be implementation of the appropriate remediation for defluoridation of water to circumvent the population from the probable health risks of F-.