Iron and sulfur biogeochemical processes involved in mercury mobility and speciation in an artificial aquifer
type: Dataset
description: Although many data are available on the Hg cycle in terrestrial surface aquatic environments, little is known on its behaviour in subsurface and deep aquifers where environmental conditions (anoxia, water saturation) may be favourable to Hg methylation. Bioavailability of Hg, a prerequisite for its methylation by sulphate or iron reducing bacteria, is mainly controlled by physico-chemical conditions and the strong affinity of Hg for organic matter or iron (oxy)hydroxides. This work presents an original experimental setup combining geochemical and microbiological approaches in order to imitate reactions observed in aquifers (i.e., Hg biosorption, solubilisation versus sequestration, speciation, dual effect of iron and sulphate). Two columns were filled in the lower half with sterile sand and in the upper half with a sterile mixture of sand and iron oxides, initially enriched with Hg(II). The water flow was ascendant. Five septa set regularly along the columns enabled water sampling from the different layers of the column without perturbing water flow or in-situ experimental conditions. After an abiotic rinsing period, the system was inoculated with a bacterial consortium and physico-chemical and microbial parameters were monitored in time and space. The inflowing groundwater was supplemented with sulphate (370 g.L-1 MgSO42-) and lactate (830 mg.L-1 sodium lactate) to encourage sulphate-reducing bacteria in the first column (A) and with molybdate (0.40 mmol.L-1) to inhibit sulphate reduction and glucose (10 g.L-1) to favour iron-reducing bacteria in the second column (B). At the end of the experiment (130 days), microbial methylation potentials were evaluated using stable isotope-spiked incubations, diversity using Denaturing Gel Gradient Electrophoresis (DGGE) followed by band sequencing and Fluorescent in situ hybridisation (FISH). Raman spectrometry was carried out to identify neo-mineral formation and selective extractions provided information on Hg distribution b…
landing page: International Conference on Mercury as a Global Pollutant (ICMGP)
keyword: conference-papers
keyword: ferri-reduction
keyword: infoeu-reposemanticsconferenceobject
keyword: mercure
keyword: methylmercure
keyword: sdebeenvironmental-sciencesbiodiversity-and-ecology
keyword: sulfato-reduction
issued: 2026-05-08T06:28:16.283062
modified: 2026-05-08T06:28:16.283067
language: en
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

Iron and sulfur biogeochemical processes involved in mercury mobility and speciation in an artificial aquifer
type: Distribution
format: HTML
access URL: https://brgm.hal.science/hal-00903916
issued: 2026-05-08T06:28:16.292796
modified: 2026-05-08T06:28:16.274824