GIS-based prediction of groundwater fluoride contamination zones in Telangana, India

Groundwater is the only perennial water resource available to rural communities, especially in semi-arid regions. This study aims to provide an overview of fluoride-contaminated groundwater in the Telangana, India, by predicting potentially affected areas. The prevalence of endemic fluorosis in different parts of Telangana has been widely reported. Therefore, it is necessary to demarcate the fluoride-affected areas to adopt the remedial measures. In this context, the available information on related environmental variables such as geological settings, hydro-morphological inputs, climatic information and soil properties have been integrated as thematic layers in an ArcGIS environment. The thematic layers and their features were assigned with suitable weights, which were normalised using the analytic hierarchy process to obtain final ranks and the weighted overlay analysis method was carried out to delineate the potential fluoride contamination (PFC) zones. The entire state was classified into four broad categories, i.e., very high (17.6%), high (15.8%), medium (32.7%) and low (33.9%), in terms of groundwater fluoride enrichment. A comparison of the output map and the reported data indicates that the PFC zone model could explain 68.7% of fluoride variation. This study is the first such attempt to offer a regional-scale PFC zone for an entire state and offers a first-hand insight into the severity of fluoride contamination.