Third national assessment
- Executive Summary
- 1.0 Introduction
- 2.0 Methods
- 3.0 Presence or Absence of Effects
- 4.0 Effluent Quality
- 5.0 Biological Monitoring Studies Investigating Observed Effects
- 6.0 Key Findings
- 7.0 Glossary
- 8.0 References
- Appendix A: Metal Mines Subject to the Metal Mining Effluent Regulations in 2013
- Appendix B: Effect Indicators, Critical Effects Sizes and Studies Conducted
- Appendix C: Mine-by-Mine Results of Studies Assessing Potential Effects
- Appendix D: Fish Tissue Mean Total Mercury Concentrations per Mine
- Appendix E: Trends in Sublethal Toxicity
- Appendix F: Trends in Sublethal Toxicity for Ore Types
- Appendix G: Annual Mean Concentrations of Effluent Characterization Data
- Appendix H: Mine-by-Mine Summary of Investigation Studies
Appendix B: Effect Indicators, Critical Effects Sizes and Studies Conducted
| Fish Population Effect Indicators | Fish Population Effect Endpoints | ||
|---|---|---|---|
| Lethal sampling design | Non-lethal sampling design | Alternative design* | |
| Survival | Age Age frequency distribution | Length frequency distribution | Length frequency analysis |
| Growth (energy use) | Body weight-at-age | Weight of young-of-the-year (YOY) (age 0) at end of growth period Length of YOY (age 0) at end of growth period | Whole animal wet weight Shell length and width Soft tissue fresh weight |
| Reproduction (energy use) | Gonad weight-at-body weight | Relative abundance of YOY (% composition of YOY) | Gonad weight-at-body weight (gonadosomatic index [GSI]) |
| Body Condition (energy storage) | Body weight-at-length | Body weight-at-length | Weight (whole animal dry weight, dry shell or soft tissue) related to shell length |
| Liver Condition (energy storage) | Liver weight-at-body weight | ||
*Alternative monitoring monitoring designs are described in the Metal Mining Technical Guidance for EEM (Environment Canada 2012a).
Table B2. Fish Habitat Effect Indicators:
- Total density (number of animals per unit area)
- Evenness index (distribution of numbers of individuals among types of organisms)
- Taxon richness (number of different types of organisms)
- Similarity index (resemblance in invertebrate community structure between exposed and reference areasFootnote 21)
| Fish Effect Endpoints | CES | Benthic Invertebrate Effect Endpoints | CES |
|---|---|---|---|
| Body weight-at-length | ± 10% | Total density | ± 2SD |
| Relative liver weight | ± 25% | Taxon richness | ± 2SD |
| Relative gonad weight | ± 25% | Evenness index | ± 2SD |
| Weight-at-age | ± 25% | Similarity index (Bray-Curtis) | ≥2SD |
| Age | ± 25% |
Note: Differences in fish population effect endpoints are expressed as percent (%) of reference mean, while differences in benthic invertebrate effect endpoints are expressed as multiples of within-reference-area standard deviations (SDs).
Table B4. Number and design of biological monitoring studies conducted or attempted by mines (number of mines conducting studies in parentheses)
| Biological Monitoring Study Design | 1st Study* | 2nd Study | 3rd Study | 4th Study | Total Studies Conducted |
|---|---|---|---|---|---|
| Control Impact and Multiple C/I | 109 (114) | 73 (77) | 27 (28) | 4 (4) | 213 |
| Gradient | 3 (3) | 2 (2) | 0 | 0 | 5 |
| Reference Condition Approach | 1 (3) | 1 (3) | 0 | 0 | 2 |
| Magnitude and Geographic Extent** | 11 (13) | 3 (3) | 14 | ||
| Investigation of Cause | 10 (13) | 21 (25) | 31 |
| Biological Monitoring Study Design | 1st Study* | 2nd Study | 3rd Study | 4th Study | Total Studies Conducted |
|---|---|---|---|---|---|
| Lethal (only) | 66 (69) | 36 (38) | 17 (17) | 3 (3) | 122 |
| Non-lethal (only) | 24 (24) | 17 (17) | 5 (5) | 0 (0) | 46 |
| Lethal and non-lethal | 12 (14) | 17 (19) | 5 (6) | 2 (2) | 36 |
| Alternative | 4 (5) | 5 (7) | 2 (2) | 0 (0) | 11 |
| Magnitude and Geographic Extent | 9 (11) | 2 (2) | 11 | ||
| Investigation of Cause | 7 (7) | 16 (18) | 23 |
| Biological Monitoring Study Design | 1st Study* | 2nd Study | 3rd Study | 4th Study | Total Studies Conducted |
|---|---|---|---|---|---|
| Fish tissue | 30 (30) | 25 (26) | 11 (12) | 1 (1) | 67 |
Note: some studies were conducted jointly by two or more mines;
* includes five mines considered to have completed the first study twice (two had a change in the location of the final discharge point, one had an important change in water treatment and two had to relaunch the assessment of effects as the reference and exposure areas sampled in the previous studies differed in terms of habitat type).
** Seven mines were not required to assess the fish component in at least one biological monitoring study because the proportion of effluent in the receiving environment was lower than 1% at a distance of 250 metres from the final discharge point.
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