Dynamic Environment & Ecosystem Health Research

In-situ remediation of legacy tailings
Dr. Emily Chapman wearing PPE holding up a small grey dried material which is one of the RAPC components.



Historical gold mine tailings
 - Ecology & biomonitoring
  - Remediation

Invasive species
- Chinese mystery snails
   - Chain pickerel


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Can wetlands impacted by 150-year old contaminated tailings be remediated in-situ to encourage natural recovery?

Note: We are continuing this research 2021-2025. If you are interested in potential applications of our research, joining our research group or would like to contribute to our data analyses, please email Dr. Linda Campbell and Dr. Emily Chapman

Please see our historical gold mine tailings page for more context about the impact of gold-mining activities 150 years ago.

Wetlands are a valuable ecological resource in Nova Scotia.
  Freshwater wetlands provide important ecosystem services, including nutrient control, flooding protection, carbon sequestration and supporting biodiversity. However, gold processing processes 150 years ago relied on freshwater sources to process the high-arsenic ore through mercury amalgamation and/or cyanide extraction. After processing, the finely-powdered material called "tailings" was slurried back into low-lying freshwater sites as seen in the pair of historical photos below. Those practices have impacted numerous freshwater ecosystems and wetlands across the province, exposing those ecosystems to chronically elevated arsenic and sometimes mercury for decades. The ecological impacts of the tailings can still be observed to this day.

Two historical photos.  One shows the interior of a stamp mill / amalgamation processing from 1860's.  Other shows the exterior of ore processing centers showing how tailings moved downstream.

Photos by E. R. Faribault, Natural Resources Canada Photo Library.  L: Photo #5214, 20-stamp mill, Dufferin Gold Mine (1893). 

R: Photo #5297 Stamp mill engine house and shaft house, Mooseland Gold Mining Co. (1897). (Open Government Licence - Canada.)

Our team is researching and developing a in-situ "Reactive Amendment - Protective Capping" (RAPC) application to support the natural recovery of tailing-impacted wetlands. Dr. Emily Chapman is leading the development of the RAPC components and the multi-stage testing of the treatments on wetland sediments. This is a 5-year interdisclipinary project funded by NSERC Alliance and St. Barbara Ltd.

We have conducted multiple experiments and R&D projects, and we are planning a series of laboratory and field experiments for 2023-2025. The interdisclipinary projects span ecotoxicology, chemistry, geology, geography, biology and cultural history topics, and our team includes researchers, collaborators and students from a wide range of disciplines.

A group of smiling scientists wearing waders standing in a wetland.

Our projects can be categorized below. More details will follow.
  • R&D of the RAPC materials and benchtop testing
Series of glass beakers holding sediment-like material and water
  • Ecotoxicology and bioacculation assessments using live organisms.
Close up GIF of an minature crayfish
  • Geochemistry and speciation investigations of the RAPC materials and sediments.
A "micro core" of sediment layers using a straw, with protective capping, reactive admendment and sediment labelled
  • One-year Geochemistry Sediment Column Experiments and Mini-core experiments. (2022 - 2025)
A row of clear PVC pipes mounted upright in wood supports wrapped with foil in a lab.

  • Half-year Bucket Mesocosm Ecology & Geochemistry Experiment (Summer-Fall 2022).
A laboratory with white buckets lined up along all walls. Buckets are covered in mesh and well-light.
  • One-year Field Mesocosm Ecology & Geochemistry Experiment (Summer 2023 - Fall 2024).  The Summer 2023 build is shown below. We will update this with the field deployment of the mesocsms.
Black mesh & wire round cages on a desk after being built.

DEEHR Team & Collaborators Resources
  • Jenna Campbell et al. 2022. Assessing the Effectiveness of Reactive Amendment Protective Capping (RAPC) at Reducing the Mobility of Arsenic and Mercury in Wetlands Impacted by Historical Gold Mine Tailings.  Poster Presentation for ARC 2022 Conference. PDF Link.
  • Liam Hill et al. 2022.  Design of a lab-scale tabletop flow-through wetland mesocosm. Poster Presentation for ARC 2022 Conference.  PDF Link.
  • Dr. Emily Chapman's seminar on low-dose selenium additives for reducing toxicity of gold mine tailing waste to earthworms. Link to You-tube video.  (note: we are not using selenium, but those early experiments has informed many of our current planning.)
DEEHR Team & Collaborators Publications
  • EEV Chapman, C Moore & LM Campbell. 2020. Evaluation of a nanoscale zero-valent iron amendment as a potential tool to reduce mobility, toxicity, and bioaccumulation of arsenic and mercury from wetland sediments. Environmental Science and Pollution Research. Published online. https://doi.org/10.1007/s11356-020-08347-6. Read online: https://rdcu.be/b3cNZ.
  • EEV Chapman, C Moore & LM Campbell. 2019. Native plants for revegetation of mercury and arsenic-contaminated historical mining waste - Can a low-dose selenium additive improve seedling growth and decrease contaminant bioaccumulation?  Water, Air, & Soil Pollution. https://doi.org/10.1007/s11270-019-4267-x. Read online for free: https://rdcu.be/bP9M7.
  • EEV Chapman, J Robinson, J Berry & LM Campbell. 2016. Can a low-dose selenium (Se) additive reduce environmental risks of mercury (Hg) and arsenic (As) in old gold mine tailings? Water, Air, & Soil Pollution. https://doi.org/10.1007/s11270-016-2909-9 Read online for free: http://rdcu.be/mFfT.

External resources:

SELECTED MEDIA MENTIONS (for full list, go to this page.)
  • SMU Press release: AMNS - SMU Partnership. Link. See media page for reporting.



- Wetlands in Nova Scotia.
- RAPC development.
- RAPC Projects
- Useful resources.

David holding up a sediment column while wearing waders in a wetland
All images and content copyright (c) members of Dynamic Environment & Ecosystem Health Research Group.