Assessment of origin and distribution of fluoride contamination in groundwater using an isotopic signature from a part of the Indo-Gangetic Plain (IGP), India

Abstract

To understand the factors controlling origin and distribution of fluoride concentration in groundwater of the Indo-Gangetic plain comprising the Indian states of Uttarakhand, Uttar Pradesh, Bihar, Jharkhand, and West Bengal, 209 groundwater samples are analyzed for their fluoride concentration, electrical conductivity (EC) and pH. The relation between fluoride concentration and d-excess are also used to investigate the role of evaporation in the fluoride enrichment. Maximum fluoride concentration is observed in Raebareli (Uttar Pradesh) and Koderma (Bihar) as 7.6 ppm and 6.8 ppm respectively, which could be explained in terms of presence of fluoride bearing minerals in the aquifer system. In all regions, most of the samples correspond to low fluoride and EC value. For large range (+20 to −10‰) of variation in d-excess, fluoride content varies within a narrow range of 0–1 ppm, therefore, evaporation cannot be ascribed as the principal factor for observed variation in fluoride content.