biostudies-literatureSun YNational Institute of Environmental Health SciencesShenzhen Science and Technology Innovation ProgramNIEHS NIH HHSNational Natural Science Foundation of ChinaNational Science Foundation124615https://www.ebi.ac.uk/biostudies/studies/S-EPMC7937834biostudies-literatureUnknown406Sediment in fluvial-deltaic plains with high-As groundwater is heterogenous but its characterization of As and Fe oxidation states lacks resolution, and is rarely attempted for aqueous and solid phases simultaneously. Here, we pair high-resolution (> 1 sample/meter) Fe extended fine-structure spectroscopy (EXAFS, n = 40) and As X-ray absorption near-edge spectroscopy (XANES, n = 49) with groundwater composition and metagenomics measurements for two sediment cores and their associated wells (n = 8) from the Yinchuan Plain in northwest China. At shallower depths, nitrate and Mn/Fe reducing sediment zones are fine textured, contain 9.6 ± 5.6 mg kg^-1 of As(V) and 2.3 ± 2.7 mg kg^-1 of As(III) with 9.1 ± 8.1 g kg^-1 of Fe(III) (hydr)oxides, with bacterial genera cJournal of hazardous materialsReduction of iron (hydr)oxide-bound arsenate: Evidence from high depth resolution sampling of a reducing aquifer in Yinchuan Plain, China.PMC7937834P42 ES010349Xia YZheng YLi ZHan LNghiem AABostick BCZhang MLiu SHan SSun YSun JEllis TfalseReduction of iron (hydr)oxide-bound arsenate: Evidence from high depth resolution sampling of a reducing aquifer in Yinchuan Plain, China.Sediment in fluvial-deltaic plains with high-As groundwater is heterogenous but its characterization of As and Fe oxidation states lacks resolution, and is rarely attempted for aqueous and solid phases simultaneously. Here, we pair high-resolution (> 1 sample/meter) Fe extended fine-structure spectroscopy (EXAFS, n = 40) and As X-ray absorption near-edge spectroscopy (XANES, n = 49) with groundwater composition and metagenomics measurements for two sediment cores and their associated wells (n = 8) from the Yinchuan Plain in northwest China. At shallower depths, nitrate and Mn/Fe reducing sediment zones are fine textured, contain 9.6 ± 5.6 mg kg^-1 of As(V) and 2.3 ± 2.7 mg kg^-1 of As(III) with 9.1 ± 8.1 g kg^-1 of Fe(III) (hydr)oxides, with bacterial genera c2021-01-01T00:00:00Z2021 Mar2025-04-04T02:38:19.433Z2024-11-15T21:04:19.193ZS-EPMC79378343331032010.1016/j.jhazmat.2020.124615