Groundwater arsenic concentrations in Vietnam controlled by sediment age

Postma, Dieke; Larsen, Flemming; Thai, Nguyen Thi; Trang, Pham Thi Kim; Jakobsen, Rasmus; Nhân, Phạm Quý; Long, Tran Vu; Viet, Pham Hung; Murray, Andrew

doi:10.1038/ngeo1540

Cited by 166 publications

(157 citation statements)

References 35 publications

Supporting

Mentioning

139

Contrasting

Order By: Relevance

“…In fact, it has been noted that sediments of older age have higher proportions of recalcitrant OM (which has not been biodegraded), something which could explain the reverse relationship between (microbially mediated) As III release and sediment age. [67] However, it is not clear why in this study 13 C-kerogen amended microcosms exhibited lower Fe III reduction and As III release than the non-amended microcosms (Fig. 2).…”

Section: Degradation Of Hexadecane and Kerogen Under Arsenic-reducingcontrasting

confidence: 39%

Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

et al. 2014

View full text Add to dashboard Cite

Environmental context. The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters.Abstract. Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of As V to As III is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13 C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13 C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant Fe III reduction and As III mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13 C-hexadecane exhibited a similar extent of Fe III reduction to the non-amended microcosms, but marginally higher As III release. Moreover, gas chromatography-mass spectrometry analysis showed that 65 % of the added 13 C-hexadecane was degraded during the 8-week incubation. The degradation of 13 C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13 C-kerogen did not enhance Fe III reduction or As III mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13 C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including Fe III and As V reduction in the subsurface.

show abstract

Section: Degradation Of Hexadecane and Kerogen Under Arsenic-reducingcontrasting

confidence: 39%

Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Arsenic is one of the most toxic elements in the environment, and has been a topic of great interest in environmental studies (Smedley and Kinniburgh, 2002;Takahashi et al, 2004;Polizzotto et al, 2005;Postma et al, 2012). Arsenic contamination is found in many waste streams in the mining industry, such as acid mine waters, tailings, and process effluents (Smedley and Kinniburgh, 2002).…”

Section: Introductionmentioning

confidence: 99%

Arsenic attenuation in geothermal streamwater coupled with biogenic arsenic(III) oxidation

Mitsunobu

Hamanura

Kataoka

et al. 2013

Applied Geochemistry

View full text Add to dashboard Cite

“…Dissolution is controlled by a suite of physicochemical conditions that vary widely within and among hydrogeologic units (9), largely as a result of variability in depositional and paleoclimatic conditions during their formation. Across basins, dissolved arsenic concentrations tend to be highest in the shallow (<100 m) subsurface (10), where the reactivity of host minerals and the organic carbon needed to dissolve them is also greatest (11,12). As a result, considerable attention has been paid to contamination mechanisms in Holocene units (up to ∼0.011 Ma in age), where affected wells are most commonly found, and to older Pleistocene units (∼0.011-2.6 Ma), where they are usually more rare (6)(7)(8)13).…”

mentioning

confidence: 99%

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Erban¹,

Gorelick²,

Zebker

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

235

126

View full text Add to dashboard Cite

Deep aquifers in South and Southeast Asia are increasingly exploited as presumed sources of pathogen- and arsenic-free water, although little is known of the processes that may compromise their long-term viability. We analyze a large area (>1,000 km 2 ) of the Mekong Delta, Vietnam, in which arsenic is found pervasively in deep, Pliocene–Miocene-age aquifers, where nearly 900 wells at depths of 200–500 m are contaminated. There, intensive groundwater extraction is causing land subsidence of up to 3 cm/y as measured using satellite-based radar images from 2007 to 2010 and consistent with transient 3D aquifer simulations showing similar subsidence rates and total subsidence of up to 27 cm since 1988. We propose a previously unrecognized mechanism in which deep groundwater extraction is causing interbedded clays to compact and expel water containing dissolved arsenic or arsenic-mobilizing solutes (e.g., dissolved organic carbon and competing ions) to deep aquifers over decades. The implication for the broader Mekong Delta region, and potentially others like it across Asia, is that deep, untreated groundwater will not necessarily remain a safe source of drinking water.

show abstract

Groundwater arsenic concentrations in Vietnam controlled by sediment age

Cited by 166 publications

References 35 publications

Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

Arsenic attenuation in geothermal streamwater coupled with biogenic arsenic(III) oxidation

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Contact Info

Product

Resources

About