Geomedical Assessment of Areas Having Varying Groundwater Fluoride Levels in Rudraprayag District, Uttarakhand

Abstract

Background: Fluorosis is a public health problem caused by excess intake of fluoride through drinking water. Groundwater around the rocks composed of fluoride-rich compounds may have a high concentration of fluoride. Thus, analyzing the geology of the area may serve as a guide for easy surveillance of fluorosis disease. Methods: The geological maps of the district were analyzed to develop a fluoride risk map for the occurrence of fluorosis i.e., the district was divided into three geological categories; high risk, intermediate, and low-risk areas. This map was correlated to the groundwater fluoride levels and prevalence and severity of dental fluorosis in the population of the corresponding area. A cross-sectional study was conducted using a purposive cluster sampling method, a total of 12 villages were selected from the district. Dental fluorosis was recorded in 558 children and 36 groundwater samples of these villages. Results: Fluoride contamination was almost nil (< 0.6ppm) in the areas composed of quartz and limestone which also showed an absence of fluorosis in the dependent population. It was moderate (0.6-1.5ppm) in areas ofaugen gneiss, porphyritic gneiss with mica schist which showed around 59.9% prevalence of fluorosis. Whereas, heavy contamination of fluoride (> 1.5ppm) was seen where granite was the main soil-forming parent rock and around 93% of the related population was affected by fluorosis. Conclusions: This study confirms the positive association between the presence of fluoride-rich rocks around the water source and the prevalence of fluorosis in the population of the area. Based on the finding of this study, geological maps of each district of the state may help in indicating the higher chances of occurrence of fluorosis in the respective districts.