Community level vulnerability of groundwater fluoride contamination and exposure by the application of multi-criteria model

Elevated fluoride (F⁻) levels in groundwater, primarily due to geogenic processes, pose significant health risks,
including dental and skeletal fluorosis and neurological disorders. This study aimed to quantify source-dependent
F⁻ exposure at the community level in selected tropical dry regions of Andhra Pradesh, India. These locations
include Chintal Cheruvu, Rompicharala, Shantamangalur, Thimmapur, and Nadendla. Community surveys and
drinking water sample analyses were conducted in these regions. Dental Fluorosis Index (DFI) was used to estimate
exposure levels across age and sex groups. Findings of surveys indicate that groundwater consumption
with high F⁻ (4.3 mg/L) results in the highest exposure dose (0.62 mg/kg/day), with Chintal Cheruvu identified
as the most affected. A strong positive correlation was observed between exposure dose, water F⁻ content, and the
Community Fluorosis Index (CFI), with R² values of 0.98 and 0.97, respectively. Dental fluorosis prevalence
exceeded 80% across all age groups, and household surveys revealed 100% unawareness of F⁻ exposure risks.
Though there exist many ways to determine the impact of fluoride, the hierarchy of regions may change with the
type of parameter chosen. To address this, we developed the Fluoride Impact Index (FII), a multi-criteria index
computed considering various parameters indicating the impact of fluoride in a region. The magnitude of FII for
Chintal Cheruvu is 0.563 which is highest among the considered regions indicating that it is most impacted
region that needs remedial measures first in the hierarchy. Rompicharala with FII as 0.252, Nadendla (0.223),
Shantamangalur (0.214), and Thimmapur (0.188) follows the hierarchy. These findings highlight the urgent need
to raise awareness about F⁻ exposure risks and to identify sustainable alternative water sources. Immediate interventions,
including human health risk assessments using the USEPA approach and the provision of safe
drinking water, are critical to achieving SDG-6 of safe drinking water for all by 2030.