Introduction to the St' Lawrence River

1
Introduction to the St. Lawrence River

Environmental Technician Field Course 2004
2
(No Transcript)
3
Water Quality Characteristics

• Physical attributes
• Microbiological attributes
• Chemical attributes

4
Physical properties

• Turbidity
• has decreased up to 10x since zebra mussels
  invaded in 1990
• Solids
• suspended
• dissolved
• Colour
• Temperature

5
Microbiological properties

• Bacteria - fecal coliforms, E. coli
• Viruses - enteric viruses
• Protozoa - Cryptosporidium, Giardia
• Algae - Cyanobacteria

6
Chemical properties

• General water chemistry parameters
• e.g. pH, conductivity, alkalinity, hardness,
  dissolved organic carbon

7
Water Chemistry Basics

• Major ions
• cations (Na, K, Ca, Mg)
• anions (Cl-, SO4, HC03)
• salinity, total dissolved solids, conductivity,
  alkalinity, and hardness

8
Water Chemistry Basics

• Oxygen content
• important for fish and aquatic biota
• solubility affected by temperature
• colder water contains more oxygen than warmer
  water
• oxygen content of water can be increased by
  photosynthesis and decreased by respiration.

9
Distribution of pH in Ontario Lakes
St. Lawrence River
10
Distribution of TDS in Ontario Lakes
St. Lawrence River
11
Nutrients

• Phosphorus (HPO4, PO43-)
• Nitrogen (N2, N03-, NO2-, NH4)
• Excess nutrients can affect water quality (e.g.
  Nitrates)

12
The Growth of Algae Depends on Nutrient Levels
Eutrophic (poor water quality)
Mesotrophic
Oligotrophic
Dead lake
13
Distribution of TP in Ontario Lakes
St. Lawrence River
14
Water Chemistry Basics - Micronutrients

• Other nutrients found in very low concentrations
  (eg. trace metals)
• Fe, Si, S, Zn, Cu, Mn, Mo
• Concentrations in water affected by redox
  potential of the water (O2 and pH)

15
Trace Metals - A Narrow Biological Window
Optimal growth
Toxicity
Deficiency
16
Contaminants

• Contaminants can be either natural (nutrients) or
  man-made (PCBs)
• trace or heavy metals
• organic compounds, especially chlorinated
  compounds
• are classified according to their persistence,
  transport, toxicity, and to accumulate in fish
  (Methylmercury).

17
Legacy Contaminants

• Many legacy contaminants in the Great Lakes /St.
  Lawrence
• (DDT, PCB, Hg and other heavy metals)
• Reside mainly in sediments
• Fate burial, breakdown, resuspension
• Show they stay or should they go?

18
Sedimentation
O2
Biologically active zone
Diagenetic zone
Depth
Burial
19
St. Lawrence River at Cornwall
20
Pilon Island
Moses-Saunders Dam
Bridge
21
Some parameters for the St. Lawrence near the
Cornwall waterfront (From Bridge to Pilon
Island).
22
Courtaulds (closed 1992)
WWTP
ICI (closed 1995)
Lake St. Lawrence
Domtar
G. M.
ALCO
Reynolds Metals
ALCOA
23
The Cornwall Area of Concern

• Designation by International Joint Commission
• Moses-Saunders Dam to Quebec Border
• Impaired Ecosystem from
• Industrial Inputs Dam construction
• Municipal Inputs
• Lake Ontario
• Mercury, PCBs, Fibres, Bacteria, Habitat

24
Remedial Action Plan

• Stage I Environmental Assessment
• Stage II Remedial Action Planning
• Stage III Implement Plan
• Stage IV - Monitoring

25
Mercury
Lake St. Lawrence
PCBs
G. M.
ALCO
Reynolds Metals
ALCOA
26
Domtar / ICI Inputs
Diffuser
27
Sedimentation Zones
28
Exposure Assessment (Benthos Hg Uptake)
29
Conceptual Model of Cornwall Waterfront
Hodson and Chapman, 2002. St. Lawrence River
Ecosystem Conference, Cornwall, ON