Use of In situ Studies with Salmonid Embryos to Evaluate Water Quality

1
Use of In situ Studies with Salmonid Embryos to
Evaluate Water Quality  
2
Introduction

• Salmonid populations are at risk throughout their
  range due to increasing levels of environmental
  degradation.
• Potential impacts include
• Stormwater
• Point-source discharges
• Changes in land use and water appropriations
• Physical effects of watershed development

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Introduction, contd.

• Complex array of potential contaminants,
  including
• Metals
• PAHs
• Pesticides
• Nutrients
• Other organics
• TSS
• TDS

4
Introduction, contd.

• Additional complexities in assessing the
  potential for environmental effects include
• Temporal variation
• Spatial variation
• Environmental
• variables
• Interactions with
• other contaminants

5
Monitoring Options

• Usual approaches
• Chemistry
• Toxicity
• Bioassessment

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Chemical Monitoring

• Pros
• Simplified approach
• Direct comparisons
• to regulatory benchmarks
• Cons
• Problematic to establish cause and effects
• Differences in bioavailability may affect
  potential to cause adverse effects
• Difficult to identify potential interactions with
  habitat factors and other contaminants

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Toxicity Tests

• Pros
• Conducted under controlled conditions
• Measures biological response
• Integrates effect of all contaminants in sample
• TIEs can be used to ID cause of toxicity
• Cons
• Provides snapshot of potential impact and
  exposure
• Involves a relatively short duration of exposure
• Doesnt incorporate potential interactions
• May result in false positives

8
Biomonitoring

• Pros
• Evaluates instream population
• under natural conditions
• Cons
• May respond to a variety of impacts difficult to
  establish which one(s) is a driver
• May be subject to natural population fluctuations
  that make it problematic to establish stressor
  effects
• May be problematic to establish exposure history
  (e.g., mobile fish populations)

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In situ Tests

• Pros
• Controlled exposure at site of interest
• Exposure integrates multiple events
• Exposure integrates ambient conditions and
  potential interactions (site-specific)
• Can focus on particular life history stages
• Can discriminate between different impacts (e.g.,
  sedimentation vs water quality)
• Bridges gap between laboratory exposures and
  bioassessment studies
• Can incorporate bioaccumulation end-points
• Leads into TIEs to identify cause

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In situ Tests, contd.

• Cons
• Vandalism
• Losses during flooding and low water events
• Losses due to disease and predation

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Example Study

• Mine located in Strathcona Park, on Vancouver
  Island
• Discharges treated wastewater to Myra Creek
• Also has potential subsurface seeps from tailings
  deposits
• Creek supports population of cutthroat trout
• Question are mine discharges affecting resident
  trout?

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Why Use an In situ Approach?

• Multiple contaminant sources (discharge points)
• Can locate exposures in direct proximity to
  discharges
• Limited fish population
• Adversely affected by destructive sampling
• Small creek
• Fish population mobile difficult to separate
  exposed from un-exposed groups

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Valued Ecosystem Components
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Study Design
Reference Site (upstream of impacts)
Flow
Tailings Area (localized seeps)
Far-field
Discharge (impact source)
Mixing zone (potential impact area)
(No impact zone)
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Study Design

• Cutthroat trout embryos -25 per Whitlock-Vibert
  box (modified to prevent escape of fry)
• Box enclosed in chicken basket, surrounded by
  rocks (reduce impact of flow, sedimentation and
  light)
• Baskets placed in excavated area of stream bed
  covered with rocks
• Monitored at regular intervals
• Laboratory control

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Exposure Locations
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Impact Analysis

• Measured biological endpoints
• Survival
• Growth
• Abnormalities
• Tissue metals concentrations
• High statistical sensitivity
• Effects limited to mixing zone in vicinity of
  discharge and localized tailings seeps
• Areas of potential impact highly localized no
  adverse effects at downstream edge of mixing zone

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Survival vs Zn in Water
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And Now for the Details

• Method considerations
• Species
• Spawning period
• Embryo stage
• Regulatory considerations

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Test Containers

• Hatch boxes
• Chicken baskets

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Selecting Exposure Locations
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Hatch Box Placement
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Monitoring

• Boxes checked periodically
• Monitor intermediate developmental endpoints
• Evaluate status
• Supporting analyses
• Water quality
• Contaminants

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Laboratory Control

• Concurrent exposure under laboratory conditions
• Verify embryo quality
• Monitor key developmental periods

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Test Termination and Endpoints

• Survival
• Hatching success
• Abnormalities
• Growth
• Swim-up
• Tissue concentrations

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Data Analysis

• Consult with a statistician!
• Lots of options, depending on study design
• Consult with a statistician!

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Next Steps

• Continued monitoring
• Prioritize streams for follow-up studies
• More focused studies to determine cause
• TIEs
• Sedimentation vs water column effects
• Source identification

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Summary

• Powerful tool for evaluating potential effects
  and causes
• Controlled exposure minimizes confounding factors
  
• High statistical sensitivity for a field test
• Cost effective, considering the amount of
  information obtained, the relevance of the
  endpoint and the duration of exposure.

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Acknowledgements

• The assistance of Armando Tang and Andreas
  Diewald (Nautilus Environmental), Sharlene
  Henderson (NVI Mining Ltd, Myra Falls Operations)
  and Mike Hagen (Environment Canada) in the
  successful completion of the field study is
  gratefully acknowledged.
• NVI Mining Ltd., Myra Falls Operations,
  generously supported the field study, as well as
  this education module.

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Contributors

• Howard C. Bailey, Ph.D.
• Senior Scientist
• Nautilus Environmental
• howard_at_nautilusenvironmental.com

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Contributors

• Ben Chalmers, MSc.
• Environmental Scientist
• NVI Mining, Myra Falls Operations
• bchalmers_at_bc.breakwater.ca

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Contributors

• James Elphick, BSc.
• Environmental Scientist
• Nautilus Environmental
• james_at_nautilusenvironmental.com

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Contributors

• Lan C. Wiborg, MPH
• Toxicologist
• City of San Diego
• Chair, SETAC NA
• Education Committee
• LWiborg_at_sandiego.gov