Arsenic in groundwater of the Red River floodplain, Vietnam: Controlling geochemical processes and reactive transport modeling

Postma, Dieke; Larsen, Flemming; Huệ, Nguyễn Thị; Duc, Thanh; Viet, Pham Hung; Nhân, Phạm Quý; Jessen, Søren

doi:10.1016/j.gca.2007.08.020

Cited by 349 publications

(305 citation statements)

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“…Moreover, the increasing IC concentrations may also have played a role. The subsequent decrease of As concentrations between days 90 and 186 can be attributed to readsorption of the arsenic on remaining Fe oxides, as suggested by Postma et al, 35 or more probably to the precipitation of As as sulfides. All sulfates had indeed disappeared below the water table in the Bornem soil from day 186 onwards.…”

Section: Relation Betweenmentioning

confidence: 67%

“…Arsenic sorption in an aerated soil is considered to be largely controlled by Fe (hydr)oxides and to a lesser extent Mn (hydr)oxides, 37 which can be proven by conducting selective extractions. 35,38 As a result, reductive dissolution of these Fe and Mn (hydr)oxides upon creation of wetland conditions can be accompanied by the release of adsorbed or occluded As. Although there is a wide consensus over the fact that Fe and Mn oxides play a role, the mechanism is not always clear.…”

Section: Greenhouse Experimentsmentioning

confidence: 99%

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Presence and mobility of arsenic in estuarine wetland soils of the Scheldt estuary (Belgium)

et al. 2009

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We aimed to assess the presence and availability of arsenic (As) in intertidal marshes of the Scheldt estuary. Arsenic content was determined in soils sampled at 4 sampling depths in 11 marshes, together with other physicochemical characteristics. Subsequently, a greenhouse experiment was set up in which pore water arsenic (As) concentrations were measured 4 times in a 298-day period in 4 marsh soils at different sampling depths (10, 30, 60 and 90 cm) upon adjusting the water table level to 0, 40 and 80 cm below the surface of these soils. The As content in the soil varied significantly with sampling depth and location. Clay and organic matter seem to promote As accumulation in the upper soil layer (0-20 cm below the surface), whereas sulfide precipitation plays a significant role at higher sampling depths (20-100 cm below the surface). The As concentrations in the pore water of the greenhouse experiment often significantly exceeded the Flemish soil sanitation thresholds for groundwater. There were indications that As release is not only affected by the reductive dissolution of Fe/Mn oxides, but also by e.g. a direct reduction of As(V) to As(III). Below the water table, sulfide precipitation seems to lower As mobility when reducing conditions have been sufficiently established. Above the water table, sulfates and bicarbonates induce As release from the solid soil phase to the pore water.

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Section: Relation Betweenmentioning

confidence: 67%

Section: Greenhouse Experimentsmentioning

confidence: 99%

Presence and mobility of arsenic in estuarine wetland soils of the Scheldt estuary (Belgium)

et al. 2009

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“…Rural residents have switched from using surface water or water from shallow dug wells to using family tubewells from Holocene aquifer and Pleistocene aquifer (Berg et al 2001) as their primary sources of drinking water. The removal of groundwater from the Pleistocene aquifer causes water to flow down from the Holocene aquifer (Postma et al 2007). A water-permeable layer of clay several meters thick separates the Holocene and Pleistocene sediments, allowing water to flow between the two aquifers (Smedle et al 2002).…”

Section: The Situation In the Red River Deltamentioning

confidence: 99%

Remarks on the current quality of groundwater in Vietnam

Luu

2017

Environ Sci Pollut Res

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This paper reviews the current quality of groundwater in Vietnam. In Vietnam, groundwater is obtained primarily from tubewells, which have high concentrations of pollutants such as As, Fe, Mn, and NH 4 + . In the areas where groundwater tests were conducted, arsenic levels ranged from 0.1-3050 μg/L, which substantially exceed the standard of 10 μg/L which has been established by the WHO. Contamination sources are distributed over a large area from the Red River Delta in the north to the Mekong River Delta in the south, putting as many as ten million people at risk of adverse health effects. Levels of arsenic and iron in sediment are strongly correlated, which indicate that the presence of arsenic in groundwater results from the reduction of arsenic bound to iron oxyhydroxides. It is important to raise awareness of these issues among the Vietnamese public by disseminating information about the negative effects of contaminated drinking water, as well as carrying out long-term research projects to identify other sources of contamination and improving water treatment technology and water management capabilities.

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“…In the last decades, some research efforts were devoted to developing a quantitative understanding of the processes governing As mobility through the implementation of reactive transport modeling [11,[23][24][25][26][27]. However, none of these previous modeling efforts implemented the role of bacteria in mediating OM degradation and related TEAPs within the numerical simulations of As mobility.…”

Section: Introductionmentioning

confidence: 99%

Considering a Threshold Energy in Reactive Transport Modeling of Microbially Mediated Redox Reactions in an Arsenic-Affected Aquifer

Rotiroti

Jakobsen

Fumagalli

et al. 2018

Water

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Abstract:The reductive dissolution of Fe-oxide driven by organic matter oxidation is the primary mechanism accepted for As mobilization in several alluvial aquifers. These processes are often mediated by microorganisms that require a minimum Gibbs energy available to conduct the reaction in order to sustain their life functions. Implementing this threshold energy in reactive transport modeling is rarely used in the existing literature. This work presents a 1D reactive transport modeling of As mobilization by the reductive dissolution of Fe-oxide and subsequent immobilization by co-precipitation in iron sulfides considering a threshold energy for the following terminal electron accepting processes: (a) Fe-oxide reduction, (b) sulfate reduction, and (c) methanogenesis. The model is then extended by implementing a threshold energy on both reaction directions for the redox reaction pairs Fe(III) reduction/Fe(II) oxidation and methanogenesis/methane oxidation. The optimal threshold energy fitted in 4.50, 3.76, and 1.60 kJ/mol e − for sulfate reduction, Fe(III) reduction/Fe(II) oxidation, and methanogenesis/methane oxidation, respectively. The use of models implementing bidirectional threshold energy is needed when a redox reaction pair can be transported between domains with different redox potentials. This may often occur in 2D or 3D simulations.

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Arsenic in groundwater of the Red River floodplain, Vietnam: Controlling geochemical processes and reactive transport modeling

Cited by 349 publications

References 50 publications

Presence and mobility of arsenic in estuarine wetland soils of the Scheldt estuary (Belgium)

Presence and mobility of arsenic in estuarine wetland soils of the Scheldt estuary (Belgium)

Remarks on the current quality of groundwater in Vietnam

Considering a Threshold Energy in Reactive Transport Modeling of Microbially Mediated Redox Reactions in an Arsenic-Affected Aquifer

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