Hydrogeochemical behavior of arsenic-enriched groundwater in the deltaic environment: comparison between two study sites in West Bengal, India.
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.
Mukherjee-Goswami
Aishwaya
A
Department of Chemistry, University of Kalyani, Nadia 741 235, West Bengal, India.
Nath
Bibhash
B
Jana
Joydev
J
Sahu
Sudip Jyoti
SJ
Sarkar
Madhav Jyoti
MJ
Jacks
Gunnar
G
Bhattacharya
Prosun
P
Mukherjee
Abhijit
A
Polya
David A
DA
Jean
Jiin-Shuh
JS
Chatterjee
Debashis
D
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*
D014874:Water Pollutants, Chemical; D001151:Arsenic