title: Hydrogeochemical behavior of arsenic-enriched groundwater in the deltaic environment: comparison between two study sites in West Bengal, India.
abstract: Groundwaters have been collected from deltaic areas of West Bengal (Chakdaha and Baruipur blocks) to record their hydrogeochemical characteristics, and to verify the mechanism of arsenic (As) release. The data reveals that shallow (<70 m) groundwaters in both areas are of Ca-Mg-HCO(3) type; however deeper (>70 m) groundwaters in Baruipur areas are slightly enriched with Na, Cl and SO(4), indicating possible saline water intrusion. The groundwater is anoxic (mean Eh: -124 and -131 mV) with high levels of As (mean: 116 and 293 microg/L), Fe (mean: 4.74 and 3.83 mg/L), PO(4) (mean: 3.73 and 3.21 mg/L) and Mn (mean: 0.37 and 0.49 mg/L), respectively for Chakdaha and Baruipur areas. The observed values of As and bicarbonate (mean: 409 and 499 mg/L) in the shallow aquifer are indicative of redox processes (e.g., oxidation of organic matter) favouring the release of As. Moreover, the presence of DOC in the shallow aquifer suggests that organic matter is young and reactive, and may actively engage in redox driven processes. Our study further confirms that both Fe- and Mn-reduction processes are the dominant mechanisms for As release in these groundwaters.
authors.affiliation: Department of Chemistry, University of Kalyani, Nadia 741 235, West Bengal, India.
authors.forename: Aishwaya
authors.initials: A
authors.lastname: Mukherjee-Goswami
authors.forename: Bibhash
authors.initials: B
authors.lastname: Nath
authors.forename: Joydev
authors.initials: J
authors.lastname: Jana
authors.forename: Sudip Jyoti
authors.initials: SJ
authors.lastname: Sahu
authors.forename: Madhav Jyoti
authors.initials: MJ
authors.lastname: Sarkar
authors.forename: Gunnar
authors.initials: G
authors.lastname: Jacks
authors.forename: Prosun
authors.initials: P
authors.lastname: Bhattacharya
authors.forename: Abhijit
authors.initials: A
authors.lastname: Mukherjee
authors.forename: David A
authors.initials: DA
authors.lastname: Polya
authors.forename: Jiin-Shuh
authors.initials: JS
authors.lastname: Jean
authors.forename: Debashis
authors.initials: D
authors.lastname: Chatterjee
mesh_terms: D001151:Arsenic / Q000032:analysis*; D004784:Environmental Monitoring; D005618:Fresh Water / Q000032:analysis*; D019015:Geologic Sediments / Q000737:chemistry*; D055593:Geological Phenomena; D007194:India; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D001151:Arsenic