How arsenic contamination influences downslope wetland plant and microbial community structure and function

Kimber E Munford; Spencer Gilbert-Parkes; Nadia C S Mykytczuk; Nathan Basiliko; Kurt M Yakimovich; Alexandre Poulain; Shaun A Watmough

doi:10.1016/j.scitotenv.2023.162839

How arsenic contamination influences downslope wetland plant and microbial community structure and function

Sci Total Environ. 2023 Jun 10:876:162839. doi: 10.1016/j.scitotenv.2023.162839. Epub 2023 Mar 14.

Authors

Kimber E Munford¹, Spencer Gilbert-Parkes², Nadia C S Mykytczuk³, Nathan Basiliko⁴, Kurt M Yakimovich⁴, Alexandre Poulain⁵, Shaun A Watmough⁶

Affiliations

¹ Environmental and Life Sciences, Trent University, Peterborough, ON K9L 0G2, Canada. Electronic address: kmunford@uoguelph.ca.
² Environmental and Life Sciences, Trent University, Peterborough, ON K9L 0G2, Canada.
³ School of the Environment, Laurentian University, Sudbury, ON P3E 2C6, Canada.
⁴ School of Natural Sciences and the Vale Living with Lakes Centre, Laurentian University, Sudbury, ON P3E 2C6, Canada.
⁵ Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
⁶ School of the Environment, Trent University, Peterborough, ON K9L 0G2, Canada.

PMID: 36921856
DOI: 10.1016/j.scitotenv.2023.162839

Abstract

Mine tailings are prevalent worldwide and can adversely impact adjacent ecosystems, including wetlands. This study investigated the impact of gold (Au) mine tailings contamination on peatland soil and pore water geochemistry, vegetation and microbial communities, and microbial carbon (C) cycling. Maximum arsenic (As) concentrations in peat and pore water reached 20,137 mg kg^-1 and 16,730 μg L^-1, respectively, but decreased by two orders of magnitude along a 128 m gradient extending from the tailings into the wetland. Carbon and other macronutrient (N, P, K) concentrations in peat and pore water significantly increased with distance from contamination. Relative percent cover and species richness of vascular and non-vascular plants significantly increased with distance into the wetland, with higher non-vascular richness being found at intermediate distances before transitioning to a vascular plant dominated community. Bacterial and archaeal community composition exhibited a decreased proportion of members of the phylum Acidobacteria (notably of the order Acidobacteriales) and increased diversity and richness of methanogens across a larger range of orders farther from the tailings source, an indication of microbial C-cycling potential. Consistent with changes in microbial communities, in vitro microbial CH₄ production potential significantly increased with distance from the contaminant source. This study demonstrates both the profound negative impact that metalliferous tailings contamination can have on above and belowground communities in peatlands, and the value of wetland preservation and restoration.

Keywords: Acid mine drainage; Arsenic; Canada; Greenhouse gas; Heavy metals; Remediation.

MeSH terms

Arsenic*
Carbon
Microbiota*
Soil / chemistry
Water
Wetlands

Substances

Arsenic
Soil
Water
Carbon