Proceedings - Teaching and Learning Centre - Simon Fraser ...

Fraser River Action Plan 3rd Research Workshop
Session 6:
Estuary Issues
Chair: P. Harrison
Study started in mid-1994 through 1995 (only full year’s data) and continues through fall 1996.
Study looked at three sites:
1. Iona; A0 = specific point contaminated site.
2. Mouth of the Fraser R., A14 = reference site.
3. Fraser Estuary Mudflat (Sturgeon Bank, Roberts Bank and Boundary Bay).
• Work covers new data on nutrient cycling, primary production, formation of nutrients, pore-waters,
cohort analyses for secondary production, pollutant transfer from sediments to invertebrates to birds,
and bird predation on invertebrates; no rate measurements have been made.
• By combining current data from the various estuary studies with historical data from the literature, it
will be possible to get some idea of Iona recovery.
• We need more work to better understand the ecology of the mudflat.
1. Iona
• In 1988 sewage input into mudflat halted — a unique opportunity to follow the response/recovery.
• Silver (Ag) is a good tracer of sewage.
• Zn and Hg are still high, especially Hg, is very high.
• Previously anoxic and azoic A0 site is recovering as indicated by nutrients, chl a, primary and
secondary production, and fish.
• Benthic invertebrate populations in intertidal mudflats are dynamic and this could have some
implications for monitoring programs (i.e., the size of the program, budget and sampling sizes).
• Dunlin may be good indicator species as they overwinter in the area, have sustainable populations,
and their toxic loads are good indicators of estuary health.
• Year 3 (1996) will involve more sampling around A0.
2. Mouth of Fraser
• Metal concentrations indicate broader, low levels of pollution.
• Need good baseline data for site A14, before Annacis and Lulu Island convert to secondary STPs.
3. Fraser Estuary Mudflat (Sturgeon Bank, Roberts Bank and Boundary Bay)
• Boundary Bay relatively pristine (with regard to metals) and may serve as good reference site.
• High stress area (MacDonald Slough, airport, coal port ferry terminal, housing developments).
• Need a better understanding of basic ecology of mudflat and how pollutants affect the area.
Deliverables:
1) Pollutant Status:
– metals (Hg, Pb, Cd, Zn)
– sewage tracer - Ag
– organics - PAHs, OCs
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