How to Assess Potential Biological Effects of Subaqueous Disposal of Mine Tailings – Literature Review and Recommended Tools and Methodologies MEND Report 2.19.1 This work was done on behalf of the Mine Environment Neutral Drainage (MEND) Program and sponsored by: The Mining Association of Canada (MAC) and MEND November 2018 How to Assess Potential Biological Effects of Subaqueous Disposal of Mine Tailings – Literature Review and Recommended Tools and Methodologies Report prepared for: MEND Secretariat Natural Resources Canada 555 Booth Street Report prepared by: Peter G.C. Campbell, PGCC Environnement Inc., 2891 rue de la Providence, Quebec City, QC G1W 2C1 William A. Price, Natural Resources Canada, 3793 Alfred Avenue, Bag 5000, 1st Floor, Room: 5000, Smithers, BC V0J 2N0 Table of Contents Figures ............................................................................................................................................. vi Tables ............................................................................................................................................. vi Glossary ............................................................................................................................................ vii Acknowledgements .............................................................................................................................. ix Executive summary ............................................................................................................................... x Sommaire Exécutif .............................................................................................................................. xv 1 Introduction ..................................................................................................................................1 1.1 Overview ....................................................................................................................................... 1 1.2 Study Objectives ........................................................................................................................... 2 2 Metal – Organism Interactions (water) .......................................................................................... 3 2.1 Brief description of the BLM ......................................................................................................... 4 2.2 BLM update .................................................................................................................................. 5 2.2.1 Metal speciation calculations ................................................................................................ 5 2.2.2 Synthetic organic ligands ....................................................................................................... 6 2.2.3 Organism acclimation ............................................................................................................ 6 2.2.4 Metal mixtures ...................................................................................................................... 6 2.2.5 Applications to trivalent metals ............................................................................................ 7 2.2.6 Analytical methods of use in estimating metal bioavailability .............................................. 8 2.3 BLM conclusion ........................................................................................................................... 10 3 Metal – Organism Interactions (ingested solids; food) ................................................................. 12 3.1 Biodynamic modelling ................................................................................................................ 12 3.2 Dietary uptake of metals ............................................................................................................ 13 3.3 Bioaccumulation of contaminants through the freshwater food chain ..................................... 15 4 Metal Bioavailability in Sediments / Subaqueous Tailings ............................................................ 18 4.1 Introduction ................................................................................................................................ 18 4.2 Pore-water metal concentrations .............................................................................................. 19 4.3 Partial extractions of sediments ................................................................................................. 20 4.4 Diagenesis (post-depositional changes in sediments over time) ............................................... 23 4.4.1 Diagenesis in freshwater sediments .................................................................................... 23 4.4.2 Post-depositional changes in sediments ............................................................................. 25 4.4.3 Post-depositional changes in submerged tailings ............................................................... 27 iii 4.5 Biomonitoring ............................................................................................................................. 30 4.5.1 Total metal bioaccumulation ............................................................................................... 30 4.5.2 Subcellular metal partitioning ............................................................................................. 32 4.5.3 Transcriptomic analysis ....................................................................................................... 34 4.5.4 Taxonomy (e-DNA) .............................................................................................................. 36 5 Relative Sensitivity of Different (Aquatic) Organisms to Metals ................................................... 48 5.1 Introduction ................................................................................................................................ 48 5.2 Species sensitivity distributions (SSDs) ....................................................................................... 48 5.3 Limitations of the SSD approach ................................................................................................ 49 6 Oxyanions .................................................................................................................................... 53 6.1 Overview ..................................................................................................................................... 53 6.1.1 Environmental chemistry .................................................................................................... 53 6.1.2 Interaction with living organisms ........................................................................................ 54 6.2 Arsenic ........................................................................................................................................ 57 6.3 Antimony .................................................................................................................................... 58 6.4 Molybdenum .............................................................................................................................. 59 6.5 Selenium ..................................................................................................................................... 60 7 Information About Subaqueous Disposal of Mine Tailings ........................................................... 62 7.1 Regulatory guidance ................................................................................................................... 62 7.2 Differences between subaqueous tailings facilities and natural water bodies .......................... 63 7.3 Review of data available on post-closure behaviour of subaqueous disposal facilities (MEND) 68 7.4 Colonization of subaqueous environments ................................................................................ 70 7.4.1 Influence of metal concentrations ...................................................................................... 71 7.4.2 Influence of chemical and physical factors other than metals ............................................ 73 7.5 Reclamation of SAD facilities ...................................................................................................... 74 8 Summary and Recommendations ................................................................................................ 76 8.1 Recapitulation ............................................................................................................................. 76 8.2 General principles for the geochemical and biological monitoring of Subaqueous Disposal Facilities ...................................................................................................................................... 76 8.3 Geochemical guiding principles .................................................................................................. 77 8.4 Biological guiding principles (tiered approach) .......................................................................... 78 8.5 Reference sites ........................................................................................................................... 79 8.6 Representative scenarios ........................................................................................................... 80 8.7 Data and knowledge gaps: ........................................................................................................