Nitrate leaching and its implication for Fe and As mobility in a Southeast Asian aquifer. Issue 4 (14th March 2023)

• Record Type: Journal Article
• Authors: Glodowska, Martyna; Ma, Yinxiao; Smith, Garrett; Kappler, Andreas; Jetten, Mike; Welte, Cornelia U
• Is Part Of: FEMS microbiology ecology. Volume 99:Issue 4(2023)
• Publication Date: 2023-03-14
• Subjects: arsenic -- groundwater -- iron -- methane -- N-DAMO -- nitrate; Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1093/femsec/fiad025
• Languages: English
• ISSNs: 0168-6496

Abstract

Abstract: The drinking water quality in Southeast Asia is at risk due to arsenic (As) groundwater contamination. Intensive use of fertilizers may lead to nitrate (NO3 − ) leaching into aquifers, yet very little is known about its effect on iron (Fe) and As mobility in water. We ran a set of microcosm experiments using aquifer sediment from Vietnam supplemented with 15 NO3 − and 13 CH4 . To assess the effect of nitrate-dependent anaerobic methane oxidation (N-DAMO) we also inoculated the sediment with two different N-DAMO enrichment cultures. We found that native microorganisms and both N-DAMO enrichments could efficiently consume all NO3 − in 5 days. However, CH4 oxidation was observed only in the inoculated microcosms, suggesting that the native microbial community did not perform N-DAMO. In uninoculated microcosms, NO3 − was preferentially used over Fe(III) as an electron acceptor and consequently inhibited Fe(III) reduction and As mobilization. The addition of N-DAMO enrichment cultures led to Fe(III) reduction and stimulated As and Mn release into the water. The archaeal community in all treatments was dominated by Ca . Methanoperedens while the bacterial community consisted of various denitrifiers. Our results suggest that input of N fertilizers to the aquifer decreases As mobility and that CH4 cannot serve as an electron donor for NO3 − reduction. Abstract : The input of nitrate to the aquifer inhibits Fe(III) reduction and As mobilization preventing As groundwater contamination.