ORCID Profile
0000-0002-7513-6469
Current Organisations
IT University of Copenhagen
,
Earth Institute at Columbia University
,
Columbia University
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Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 2018
Publisher: American Chemical Society (ACS)
Date: 24-07-2018
Publisher: Elsevier BV
Date: 07-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1EM00303H
Abstract: A more ubiquitous use of process-based models will enhance the information gained from biogeochemical experimentation through both, a more rigorous interpretation of acquired data and the optimal design of future experiments.
Publisher: American Chemical Society (ACS)
Date: 20-02-2023
Publisher: Elsevier BV
Date: 2015
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/EN13222
Abstract: Environmental context Arsenic is one of the most common contaminants at US Superfund sites therefore, establishing techniques to accelerate As remediation could benefit many sites. In a pilot scale study, we determined that addition of oxalic acid to the subsurface has the potential to increase arsenic release from sediments and possibly improve remediation efficiency by pump and treat techniques. Because pump and treat remediation can require many decades to sufficiently decrease contaminant levels, methods for improving remediation could lead to substantial savings in time and resources. Abstract Arsenic is a prevalent contaminant at a large number of US Superfund sites establishing techniques that accelerate As remediation could benefit many sites. Hundreds of tonnes of As were released into the environment by the Vineland Chemical Co. in southern New Jersey during its manufacturing lifetime (1949–1994), resulting in extensive contamination of surface and subsurface soils and sediments, groundwater, and the downstream watershed. Despite substantial intervention at this Superfund site, sufficient aquifer clean up could require many decades if based on traditional pump and treat technologies only. Laboratory column experiments have suggested that oxalic acid addition to contaminated aquifer solids could promote significant As release from the solid phase. To evaluate the potential of chemical additions to increase As release in situ and boost treatment efficiency, a forced gradient pilot scale study was conducted on the Vineland site. During spring and summer 2009, oxalic acid and bromide tracer were injected into a small portion (~50m2) of the site for 3 months. Groundwater s les indicate that introduction of oxalic acid led to increased As release. Between 2.9 and 3.6kg of As were removed from the s led wells as a result of the oxalic acid treatment during the 3-month injection. A comparison of As concentrations on sediment cores collected before and after treatment and analysed using X-ray fluorescence spectroscopy suggested reduction in As concentrations of ~36% (median difference) to 48% (mean difference). Although further study is necessary, the addition of oxalic acid shows potential for accelerating treatment of a highly contaminated site and decreasing the As remediation time-scale.
Publisher: Springer Science and Business Media LLC
Date: 14-07-2023
Publisher: Elsevier BV
Date: 02-2016
Publisher: American Chemical Society (ACS)
Date: 30-09-2020
Publisher: Elsevier BV
Date: 2022
Publisher: American Geophysical Union (AGU)
Date: 28-11-2019
DOI: 10.1029/2019GL084767
Abstract: Elevated arsenic in Bengal Basin aquifers threatens human health. Most deep ( m) groundwater in Pleistocene aquifers is low in arsenic however higher concentrations have been reported in the southwest border region. Here, we establish that this extensive arsenic contamination at depth is not associated with well failure. A combination of geochemistry and flow modeling constrains the factors that contribute to arsenic contamination at depth in this region. Deep groundwater in the affected area is younger (2.0 ± 0.6 kyr) than deep, low‐arsenic groundwater elsewhere (12.0 ± 4.0 kyr) based on radiocarbon. Stratigraphic data indicate pre‐Holocene deposition of the contaminated aquifers, but few low‐permeability strata. Numerical modeling indicates that this stratigraphic anomaly permits a natural flow system that transports shallow groundwater to depth. Thus, in areas lacking low‐permeability layers, arsenic contamination can occur in pre‐Holocene aquifers and is probably not an early sign of future deep contamination in regions with interbedded low‐permeability strata.
Publisher: Elsevier BV
Date: 05-2020
Publisher: American Chemical Society (ACS)
Date: 19-01-2018
Abstract: Considerable questions persist regarding tungsten geochemistry in natural systems, including which forms of tungsten are found in soils and how adsorption regulates dissolved tungsten concentrations. In this study, we examine tungsten speciation and solubility in a series of soils at firing ranges in which tungsten rounds were used. The metallic, mineral, and adsorbed forms of tungsten were characterized using X-ray absorption spectroscopy and X-ray microprobe, and desorption isotherms for tungsten in these soils were used to characterize its solid-solution partitioning behavior. Data revealed the complete and rapid oxidation of tungsten metal to hexavalent tungsten(VI) and the prevalence of adsorbed polymeric tungstates in the soils rather than discrete mineral phases. These polymeric complexes were only weakly retained in the soils, and porewaters in equilibrium with contaminated soils had 850 mg L
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-06-2017
Abstract: Diatoms can access mineral iron from dust if it is reduced, and reduced particulate iron is common in glacial dust sources.
Publisher: Springer Science and Business Media LLC
Date: 16-02-2023
Publisher: American Geophysical Union (AGU)
Date: 08-2016
DOI: 10.1002/2016WR018891
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 12-2015
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 08-2016
Publisher: American Chemical Society (ACS)
Date: 26-08-2016
Publisher: Elsevier BV
Date: 07-2021
Publisher: American Chemical Society (ACS)
Date: 24-06-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1EN00502B
Abstract: Synchrotron X-ray absorption spectroscopy analysis of high arsenic Guizhou coal s les reveals stable nano-aggregates of As( v ) bound through edge-sharing with Fe( iii )-oxyhydroxide within an organic matter matrix.
Publisher: CRC Press
Date: 23-08-2018
Publisher: American Chemical Society (ACS)
Date: 20-04-2018
Publisher: MDPI AG
Date: 20-10-2020
DOI: 10.3390/W12102932
Abstract: Superlative levels of arsenic (As) in groundwater and sediment often result from industrial pollution, as is the case for a coastal aquifer in Southern Italy, with a fertilizer plant atop. Understanding conditions under which As is mobilized from the sediments, the source of that As, is necessary for developing effective remediation plans. Here, we examine hydrogeological and geochemical factors that affect groundwater As concentrations in a contaminated coastal aquifer. Groundwater has been subject to pump-and-treat at a massive scale for more than 15 years and is still ongoing. Nevertheless, As concentrations (0.01 to 100 mg/L) that are four orders of magnitude more than Italian drinking water standard of 10 μg/L are still present in groundwater collected from about 50 monitoring wells over three years (2011, 2016, and 2018). As was quantified in three different locations by sequential extractions of 29 sediment cores in 2018 (depth 2.5 m to −16.5 m b.g.l.), combined with groundwater As composition, the aqueous and solid partitioning of As were evaluated by partition coefficient (Kd) in order to infer the evolution of the contaminant plumes. Most sediment As is found in easily extractable and/or adsorbed on amorphous iron oxides/hydroxides fractions based on sequential extractions. The study shows that As contamination persists, even after many years of active remediation due to the partitioning to sediment solids. This implies that the choice of remediation techniques requires an improved understanding of the biogeochemical As-cycling and high spatial resolution characterization of both aqueous and solid phases for sites of interest.
Location: United States of America
Start Date: 2016
End Date: 2017
Funder: German Research Foundation
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