Noble gases in aquitard provide insight into underlying subsurface stratigraphy and free gas formation DOI Creative Commons
Alexandra Lightfoot,

Emiliano Stopelli,

Michael Berg

и другие.

Vadose Zone Journal, Год журнала: 2022, Номер 22(1)

Опубликована: Ноя. 17, 2022

Abstract Biogeochemical gas production resulting in free phase formation can severely affect groundwater and solute transport aquifers. Such gas–water interactions are important aquifers affected by geogenic As, which commonly associated with biogeochemical CH 4 production. Additionally, the influence of aquitards on As concentrations contaminated has recently been challenged. These observations prompted analysis through a heterogeneous aquitard overlying high −gas‐producing zone an As‐contaminated aquifer. A sediment core taken was analyzed for noble gases to assess how physically contributes underlying Results reveal that pore space is unsaturated two separate layers hanging water constrained air‐like phase. This interlayering saturated zones identifies aquitard's stratigraphy as key determining hydrostatic pressure—a main control (i.e., ) The partly conditions reduce pressure 30% compared fully conditions. To our knowledge, this first study applying examine physical state Further, such low conductivity might provide preferential pathways periodic flow, fostering aquitard–aquifer transport. Groundwater samples additionally collected throughout site confirm more widespread degassing than previously reported. Up 90% expected atmospheric lost from immediately below investigated core.

Язык: Английский

Sulfate reduction accelerates groundwater arsenic contamination even in aquifers with abundant iron oxides DOI
Athena Nghiem, Henning Prommer, M. Rajib H. Mozumder

и другие.

Nature Water, Год журнала: 2023, Номер 1(2), С. 151 - 165

Опубликована: Фев. 16, 2023

Язык: Английский

Процитировано

30

Predicting Redox Conditions in Groundwater at a National Scale Using Random Forest Classification DOI Creative Commons
Anthony J. Tesoriero, Susan A. Wherry, Danielle I. Dupuy

и другие.

Environmental Science & Technology, Год журнала: 2024, Номер 58(11), С. 5079 - 5092

Опубликована: Март 7, 2024

Redox conditions in groundwater may markedly affect the fate and transport of nutrients, volatile organic compounds, trace metals, with significant implications for human health. While many local assessments redox have been made, spatial variability reaction rates makes determination at regional or national scales problematic. In this study, were predicted contiguous United States using random forest classification by relating measured water quality data from over 30,000 wells to natural anthropogenic factors. The model correctly oxic/suboxic 78 79% samples out-of-bag hold-out sets, respectively. Variables describing geology, hydrology, soil properties, hydrologic position among most important factors affecting likelihood oxic groundwater. Important variables tended relate aquifer recharge, travel time, prevalence electron donors, which are key drivers Partial dependence plots suggested that decreased sharply as streams approached gradually depth below table increased. probability increased base flow index values increased, likely due well-drained soils geologic materials high areas. topographic wetness (TWI) decreased. High occur areas a propensity standing overland flow, limit delivery dissolved oxygen recharge; higher TWI also tend discharge areas, contain long times. A second was developed predict elevated manganese (Mn) concentrations (i.e., ≥50 μg/L). Mn relied on same be used identify where Mn-reducing there is an risk domestic supplies concentrations. Model predictions produced study help regions country vulnerability stream groundwater-derived contaminants.

Язык: Английский

Процитировано

15

Structural Fe(II)-induced generation of reactive oxygen species on magnetite surface for aqueous As(III) oxidation during oxygen activation DOI

Fangyuan Meng,

Hui Tong, Chunhua Feng

и другие.

Water Research, Год журнала: 2024, Номер 252, С. 121232 - 121232

Опубликована: Янв. 29, 2024

Язык: Английский

Процитировано

8

Lead (Pb) concentrations and speciation in residential soils from an urban community impacted by multiple legacy sources DOI Creative Commons
Ezazul Haque, Peter S. Thorne, Athena Nghiem

и другие.

Journal of Hazardous Materials, Год журнала: 2021, Номер 416, С. 125886 - 125886

Опубликована: Апрель 16, 2021

Язык: Английский

Процитировано

41

Iron mineral transformations and their impact on As (im)mobilization at redox interfaces in As-contaminated aquifers DOI
Agnes Kontny, M. Schneider, Elisabeth Eiche

и другие.

Geochimica et Cosmochimica Acta, Год журнала: 2021, Номер 296, С. 189 - 209

Опубликована: Янв. 13, 2021

Язык: Английский

Процитировано

37

Carbon and methane cycling in arsenic-contaminated aquifers DOI Creative Commons

Emiliano Stopelli,

Vu Thi Duyen, Henning Prommer

и другие.

Water Research, Год журнала: 2021, Номер 200, С. 117300 - 117300

Опубликована: Май 27, 2021

Geogenic arsenic (As) contamination of groundwater is a health threat to millions people worldwide, particularly in alluvial regions South and Southeast Asia. Mitigation measures are often hindered by high heterogeneities As concentrations, the cause(s) which elusive. Here we used comprehensive suite stable isotope analyses hydrogeochemical parameters shed light on mechanisms typical high-As Holocene aquifer near Hanoi where advected low-As Pleistocene aquifer. Carbon signatures (δ13C-CH4, δ13C-DOC, δ13C-DIC) provided evidence that fermentation, methanogenesis methanotrophy actively contributing heterogeneity. Methanogenesis occurred concurrently levels (>200 µg/L) DOC-enriched aquitard pore water infiltrates into Along flowpath Holocene/Pleistocene transition, methane oxidation causes strong shift δ13C-CH4 from -87‰ +47‰, indicating reactivity. These findings demonstrate previously overlooked role cycling DOC infiltration aquifers.

Язык: Английский

Процитировано

37

Groundwater fluoride across the Punjab plains of Pakistan and India: Distribution and underlying mechanisms DOI Creative Commons
Junaid Ali Khattak, Abida Farooqi,

Ishtiaque Hussain

и другие.

The Science of The Total Environment, Год журнала: 2021, Номер 806, С. 151353 - 151353

Опубликована: Окт. 29, 2021

Язык: Английский

Процитировано

37

Surface Flooding as a Key Driver of Groundwater Arsenic Contamination in Southeast Asia DOI
Craig T. Connolly, Mason Stahl, Beck DeYoung

и другие.

Environmental Science & Technology, Год журнала: 2021, Номер 56(2), С. 928 - 937

Опубликована: Дек. 24, 2021

Chronic exposure to groundwater contaminated with geogenic arsenic (As) poses a significant threat human health worldwide, especially for those living on floodplains in South and Southeast (S–SE) Asia. In the alluvial deltaic aquifers of S–SE Asia, aqueous As concentrations vary sharply over small spatial scales (10–100 m), making it challenging identify where contamination is present mitigate exposure. Improved mechanistic understanding factors that control levels essential develop models accurately predict spatially variable concentrations. Here we demonstrate surface flooding duration interannual frequency are master variables integrate key hydrologic biogeochemical processes affect A machine-learning model based high-resolution, satellite-derived, long-term measures effectively predicts heterogeneous at fine Cambodia, Vietnam, Bangladesh. Our approach can be reliably applied locations safe unsafe sources sufficient accuracy management decisions by solely using remotely sensed information. This work important evaluate exposure, impacts public health, shed light underlying hydrogeochemical drive mobilization into groundwater.

Язык: Английский

Процитировано

37

Fermentation, methanotrophy and methanogenesis influence sedimentary Fe and As dynamics in As-affected aquifers in Vietnam DOI Creative Commons
Martyna Głodowska, M. Schneider, Elisabeth Eiche

и другие.

The Science of The Total Environment, Год журнала: 2021, Номер 779, С. 146501 - 146501

Опубликована: Март 18, 2021

Язык: Английский

Процитировано

29

Arsenic speciation transformation in soils with high geological background: New insights from the governing role of Fe DOI

Manshu Gao,

Yue Su, Jiabao Gao

и другие.

Chemosphere, Год журнала: 2022, Номер 302, С. 134860 - 134860

Опубликована: Май 9, 2022

Язык: Английский

Процитировано

18