Groundwater arsenic contamination on the Ganges Delta: biogeochemistry, hydrology, human perturbations, and human suffering on a large scale

Harvey, Charles F.; Swartz, Christopher H.; Badruzzaman, A. B. M.; Keon-Blute, Nicole; Yu, Winston; Ali, Muhammad; Jay, Jenny; Beckie, Roger; Niedan, V.; Brabander, Daniel J.; Oates, Peter M.; Ashfaque, Khandaker N.; Islam, Shafiqul; Hemond, Harold F.; Ahmed, Mubashir

doi:10.1016/j.crte.2004.10.015

Cited by 193 publications

(165 citation statements)

References 16 publications

(48 reference statements)

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“…However, it should be noted that as all groundwater and surface water samples were collected at the same time of the year, no study of seasonal trends was undertaken. The groundwater δ 18 O range of the ECW is within the range of monsoon precipitation composition range of Mukherjee (2006) and Sengupta and Sarkar (2006) during 2004-2005. This indicates that groundwater of the area is probably recharged primarily from precipitation with similar isotopic composition to the present.…”

Section: Discussionmentioning

confidence: 69%

“…The slight deviation of the samples from the LMWL suggest that some evaporation of rainfall occurs prior to or during infiltration, or there might be some mixing of the infiltrating water with preexisting soil moisture that has undergone several cycles of evaporation and wetting. Harvey et al (2005) concluded that the recharge in their study area in Bangladesh is very complex: in addition to direct infiltration from precipitation, recharge may also take place from the bottom of ponds, ox-bow lakes, rivers, and re-infiltration of groundwater withdrawn for irrigation. Such a scenario is probably also true for the present wetland especially in areas where the top aquitard is absent and the piezometric surface is below the water table of the aquitard.…”

Section: Discussionmentioning

confidence: 99%

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Understanding wetland sub-surface hydrology using geologic and isotopic signatures

Sikdar

Sahu

2009

Hydrol. Earth Syst. Sci.

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Abstract. This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) -a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×10 3 m 3 /day. δ 18 O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mix-ing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also present in groundwater of various depths. Therefore, aquifers of wetland and surrounding urban areas which are heavily dependent on groundwater are vulnerable to pollution. In the area south of ECW isotope data indicates no interaction between shallow and deep aquifer and hence this area may be a better location to treat sewage water than within ECW. To reduce the threat of pollution in ECW's aquifer, surface water-groundwater interaction should be minimized by regulating tubewell operation time, introducing treated surface water supply system and artificial recharging of the aquifer.

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Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Understanding wetland sub-surface hydrology using geologic and isotopic signatures

Sikdar

Sahu

2009

Hydrol. Earth Syst. Sci.

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“…That reduction of Fe and Mn oxides, a governing process for As mobilization has not been fully supported is due to several controversial points; e.g., weak relationship between dissolved As and Fe [5,14]; source of organic matter -either sedimentary organic matter or infiltration of labile organic carbon [4,46,51], dissolved Fe, chemical form of reduced Fe oxyhydroxides [24,42], and transportation process of As [52]. Given the previous studies and the present results, we conclude that the spatial variation of redox conditions and the subsequent inconsistent distribution of As and dissolved Fe in groundwater of the upper aquifer are attributable to a range of pressures.…”

Section: Mechanism Of Arsenic Mobilizationmentioning

confidence: 99%

“…recent inflow of labile organic C into groundwater due to pumping for irrigation to shallow aquifers containing As-bearing iron oxyhydroxide, can cause significant release of As to groundwater [4,32,52]. Arsenic leached out of the upper muddy layer is translocated to the lower sand (aquifer) that may be expedited by infiltrated PO 4 3 fertilizer-enhanced movement of As from the muddy layer [27,31].…”

Section: Mechanism Of Arsenic Mobilizationmentioning

confidence: 99%

Arsenic Contamination in Groundwater of Bangladesh: Perspectives on Geochemical, Microbial and Anthropogenic Issues

Anawar

Akai

Mihaljevič

et al. 2011

Water

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A groundwater, sediment and soil chemistry and mineralogical study has been performed to investigate the sources and mobilization process of Arsenic (As) in shallow aquifers of Bangladesh. The groundwater from the shallow aquifers is characterized by high concentrations of Arsenic (47.5-216.8 µg/L), iron (0.85-5.83 mg/L), and phosphate, along with high electrical conductivity (EC). The groundwater has both very low oxidation-reduction potential (Eh) and dissolved oxygen (DO) values indicating reducing conditions. By contrast, the deep aquifers and surface waters (pond, canal) have very low concentrations of Arsenic (<6 µg/L), iron (0.12-0.39 mg/L), and phosphate along with a relatively low EC. Furthermore, the values of Eh and DO are high, indicating oxic to suboxic conditions. Arsenic is inversely correlated with Eh values in the upper aquifer, whereas no relationship in the deeper aquifer is observed. These results suggest that As mobilization is clearly linked to the development of reducing conditions. The clayey silt, OPEN ACCESSWater 2011, 3 1051 enriched in Fe, Mn, Al oxides and organic matter, and deposited in the middle unit of shallow aquifers, contains moderately high concentrations of As, whereas the sediments of deep aquifers and silty mud surface soils from paddy fields and ponds contain a low content of As (Daudkandi area). Arsenic is strongly correlated with the concentrations of Fe, Mn and Al oxides in the core samples from the Daudkandi and Marua areas. Arsenic is present in the oxide phase of Fe and Mn, phyllosilicate minerals and in organic matter in sediments. This study suggests that adsorption or precipitation of As-rich Fe oxyhydroxide on the surface or inner sites of biotite might be responsible for As concentrations found in altered biotite minerals by Seddique et al. Microbially or geochemically mediated reductive dissolution of Fe oxyhydroxides is the main mechanism for As release. The reducing conditions are caused by respiratory decomposition of organic matter, either sedimentary or labile organic C. The process can be accelerated by agricultural activity and domestic organic wastes. An agricultural fertilizer can directly contribute As to groundwater as well as promote As mobilization by ion-exchange with phosphorus.

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“…4,5 For example, in Bangladesh, the arsenite released into the ground water contaminates drinking water, thus causing serious water problems. 6 Arsenate is a chemical analogue of phosphate, and may interfere with oxidative phosphorylation. 1 Accordingly, under the phosphate limited condition, some microorganisms, such as phytoplankton and bacteria, uptake dissolved arsenate through their phosphate-concentrating mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Classification for Dimethylarsenate-decomposing Bacteria Using a Restrict Fragment Length Polymorphism Analysis of 16S rRNA Genes

et al. 2004

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A new monitoring system for bacterial communities involving dimethylarsinic acid (DMAA) decomposition was provided by combining the MPN (Most Probable Number) method and RFLP (restriction-fragment-length polymorphism analysis). The abundance of DMAA decomposing bacteria was estimated by the MPN method using a bacterial culture medium, which included DMAA as the sole carbon source, indicating bacterial cell densities of 1700 cells/ml in Lake Kahokugata and 330 cells/ml in Lake Kibagata. After isolating the dominant bacteria using agar plates, the isolates were classified into some genotype groups by RFLP analysis using 16S rDNA sequences. Classification of the RFLP analysis indicated that 14 isolates of Lake Kahokugata were classified into 6 types, which included 2 dominant types related to genus Pseudomonas, while 8 isolates of Lake Kibagata displayed 6 types including one or two isolates. Moreover, the RFLP types were unique for each lake, suggesting that DMAA decomposing bacteria were specific for the aquatic environment related to the arsenic cycle. The activities of DMAA decomposition mostly matched with the RFLP type category of the isolates. Accordingly, combining the MPN method with the RFLP analysis will play an important role in elucidating the distributions and dynamics of the DMAA-decomposing bacterial community.

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Groundwater arsenic contamination on the Ganges Delta: biogeochemistry, hydrology, human perturbations, and human suffering on a large scale

Cited by 193 publications

References 16 publications

Understanding wetland sub-surface hydrology using geologic and isotopic signatures

Understanding wetland sub-surface hydrology using geologic and isotopic signatures

Arsenic Contamination in Groundwater of Bangladesh: Perspectives on Geochemical, Microbial and Anthropogenic Issues

Classification for Dimethylarsenate-decomposing Bacteria Using a Restrict Fragment Length Polymorphism Analysis of 16S rRNA Genes

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