title: Hydrogeochemical processes controlling the high fluoride concentration in groundwater: a case study at the Boden block area, Orissa, India.
abstract: The present investigation reports the assessment of hydrochemical/geochemical processes controlling the concentration of fluoride in groundwater of a village in India (Boden block, Orissa). Boden block is one of the severely affected fluoride-contaminated areas in the state of Orissa (India). The sampling and subsequent analysis of water samples of the study area was carried out following standard prescribed methods. The results of the analysis indicate that 36.60% groundwater F(-) concentration exceeds the limit prescribed by the World Health Organization for drinking water. The rock interaction with groundwater containing high concentration of HCO(3)(-) and Na(+) at a higher pH value of the medium could be one of the important reasons for the release of F(-) from the aquatic matrix into groundwater. Geochemical classification of groundwater based on Chadha rectangular diagram shows that most of the groundwater samples having fluoride concentration more than 1.5 mg L(-1) belongs to the Na-K-HCO(3) type. The saturation index values evaluated for the groundwater of the study area indicated that it is oversaturated with respect to calcite, whereas the same is undersaturated with respect to fluorite content. The deficiency of calcium ion concentration in the groundwater from calcite precipitation favors fluorite dissolution leading to excess of fluoride concentration. The risk index was calculated as a function of fluoride level in drinking water and morbidity of fluorosis categorizes high risk for villages of Amera and Karlakote panchayat of Boden block.
authors.affiliation: Post-Graduate Department of Chemistry, Ravenshaw University, Cuttack-753 003, Orissa, India. rkdey@rediffmail.com
authors.forename: R K
authors.initials: RK
authors.lastname: Dey
authors.forename: S K
authors.initials: SK
authors.lastname: Swain
authors.forename: Sulagna
authors.initials: S
authors.lastname: Mishra
authors.forename: Prachi
authors.initials: P
authors.lastname: Sharma
authors.forename: Tanushree
authors.initials: T
authors.lastname: Patnaik
authors.forename: V K
authors.initials: VK
authors.lastname: Singh
authors.forename: B N
authors.initials: BN
authors.lastname: Dehury
authors.forename: Usha
authors.initials: U
authors.lastname: Jha
authors.forename: R K
authors.initials: RK
authors.lastname: Patel
mesh_terms: D004784:Environmental Monitoring; D005459:Fluorides / Q000032:analysis* / Q000737:chemistry; D055593:Geological Phenomena; D060587:Groundwater / Q000737:chemistry*; D007194:India; D007700:Kinetics; D008956:Models, Chemical; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D014874:Water Pollutants, Chemical; D005459:Fluorides