Arsenic-enriched groundwaters of India, Bangladesh and Taiwan--comparison of hydrochemical characteristics and mobility constraints.
J Environ Sci Health A Tox Hazard Subst Environ Eng
; 46(11): 1163-76, 2011.
Article
in En
| MEDLINE
| ID: mdl-21879849
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Arsenic
/
Water Pollutants, Chemical
/
Drinking Water
/
Groundwater
Country/Region as subject:
Asia
Language:
En
Journal:
J Environ Sci Health A Tox Hazard Subst Environ Eng
Journal subject:
TOXICOLOGIA
Year:
2011
Document type:
Article
Affiliation country:
Taiwán