title: Arsenic-enriched groundwaters of India, Bangladesh and Taiwan--comparison of hydrochemical characteristics and mobility constraints.
abstract: Arsenic (As) enrichment in groundwater has become a major global environmental disaster. Groundwater samples were collected from 64 sites located in the districts of 24-Parganas (S), and Nadia in West Bengal, India (Bhagirathi sub-basin), and 51 sites located in the districts of Comilla, Noakhali, Magura, Brahman baria, Laxmipur, Munshiganj, Faridpur and Jhenaida in Bangladesh (Padma-Meghna sub-basin). Groundwater samples were also collected from two As-affected areas (Chianan and Lanyang plains) of Taiwan (n = 26). The concentrations of major solutes in groundwater of the Padma-Meghna sub-basin are more variable than the Bhagirathi sub-basin, suggesting variations in the depositional and hydrological settings. Arsenic concentrations in groundwaters of the studied areas showed large variations, with mean As concentrations of 125 μg/L (range: 0.20 to 1,301 μg/L) in Bhagirathi sub-basin, 145 μg/L (range: 0.20 to 891 μg/L) in Padma-Meghna sub-basin, 209 μg/L (range: 1.3 to 575 μg/L) in Chianan plain, and 102 μg/L (range: 2.5 to 348 μg/L) in Lanyang plain groundwater. The concentrations of Fe, and Mn are also highly variable, and are mostly above the WHO-recommended guideline values and local (Indian and Bangladeshi) drinking water standard. Piper plot shows that groundwaters of both Bhagirathi and Padma-Meghna sub-basins are of Ca-HCO(3) type. The Chianan plain groundwaters are of Na-Cl type, suggesting seawater intrusion, whereas Lanyang plain groundwaters are mostly of Na-HCO(3) type. The study shows that reductive dissolution of Fe(III)-oxyhydroxides is the dominant geochemical process releasing As from sediment to groundwater in all studied areas.
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, 168 University Road, Ming-Shung, Chiayi County, Taiwan. jyoti_maity@yahoo.com
authors: Jyoti Prakash
authors: JP
authors: Maity
authors: Bibhash
authors: B
authors: Nath
authors: Chien-Yen
authors: CY
authors: Chen
authors: Prosun
authors: P
authors: Bhattacharya
authors: Ondra
authors: O
authors: Sracek
authors: Jochen
authors: J
authors: Bundschuh
authors: Sandeep
authors: S
authors: Kar
authors: Roger
authors: R
authors: Thunvik
authors: Debashis
authors: D
authors: Chatterjee
authors: Kazi Matin
authors: KM
authors: Ahmed
authors: Gunnar
authors: G
authors: Jacks
authors: Arun B
authors: AB
authors: Mukherjee
authors: Jiin-Shuh
authors: JS
authors: Jean
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D001459:Bangladesh; D060766:Drinking Water / Q000032:analysis / Q000737:chemistry* / Q000592:standards; D004784:Environmental Monitoring / Q000379:methods; D005290:Ferric Compounds / Q000032:analysis / Q000737:chemistry; D060587:Groundwater / Q000032:analysis / Q000737:chemistry*; D007194:India; D007501:Iron / Q000032:analysis / Q000737:chemistry / Q000592:standards; D008345:Manganese / Q000032:analysis / Q000737:chemistry / Q000592:standards; D017895:Manganese Compounds / Q000032:analysis / Q000737:chemistry; D010084:Oxidation-Reduction; D013624:Taiwan; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D060766:Drinking Water; D005290:Ferric Compounds; D017895:Manganese Compounds; D014874:Water Pollutants, Chemical; D008345:Manganese; C092844:ferric oxyhydroxide; D007501:Iron; D001151:Arsenic