All

Nutrients and how they get into Lake Winnipeg

We were exceedingly pleased to receive as our September guest speaker, the distinguished retired professor and researcher, Dr. Eva Pip. Throughout her nearly forty years at The University of Winnipeg, she served the community as a researcher, academic, and advocate for clean water. She was twice honoured by the University of Winnipeg with The Clarence Atchison Award for Excellence in Community Service.

Dr. Pip also happens to be very knowledgeable about plants, gardening, trees, home water ponds, safe ways of eliminating garden pests, etc. A truly remarkable person, the Heritage Group extended her a warm welcome to Red River College.

The most important issues that affect Lake Winnipeg are nutrients and  Zebra mussels. Dr. Pip’s presentation focused on the first: nutrients, and how they get into Lake Winnipeg. 

Why are we so focussed on Nutrients?

Because of blue-green algae. Algae growth is a normal part of a lake’s ecosystem. But excessive blue-green blooms are toxic and a hazard. High levels of nitrogen and phosphorus are responsible for increasing algae in Manitoba lakes. Some algae get nitrogen from the air, but the rest get it from the water. All algae obtain phosphorus from water. 90% of Manitoba surface waters have phosphorus as the primary limiting nutrient. Reducing phosphorus and nitrogen levels will decrease algae growth.

Eutrophication

Lake Winnipeg blue-green algae in satellite photo from NASA

The process by which a body of water becomes excessively rich in nutrients is called eutrophication. This results in:

  • Increased algae growth
  • Decreased light penetration
  • Decreased macrophytes (plants that grow on the bottom) production; therefore, decreased oxygen
  • Increased plant decay
  • Increased sedimentation (sinks to the bottom and builds up)
  • Decreased biodiversity (e.g. there were 11 species of native fresh water mussels, now that has decreased to two.)

Sources of nitrogen and phosphorus in Manitoba

  • Domestic sewage
  • Agriculture:  crops, livestock
  • Manufacturing industries
  • Logging and land clearing, especially on the east side of Lake Winnipeg
  • Solid waste: landfills
  • Cottages (there are tens of thousands) and recreation
  • Mining (e.g. gold)
  • Deliberate addition to tap water

More than half of the nutrients flowing into Lake Winnipeg are from the Red River, one quarter from the Winnipeg River, and less from its many other tributaries.

Sources of Water Pollution

  1. Point sources (coming from a specific place, such as the effluent from a treatment plant)
    These are easy to identify, monitor and regulate.
  2. Non-point sources (coming from broad, diffuse areas, such as from many cottages)
    These are difficult to identify and control, and expensive to clean up.

Domestic Wastes

  • Human generated wastes
    • dish soaps, cleaners with phosphorous and ammonia, household products, food waste and garburators
  • Urban sewage treatment plants
    • The North End sewage plant, for example, contributes 600 kg. of phosphorous per day.
    • When storms hit, raw sewage often goes straight into the river.
  • Community sewage Lagoons
    • The Charleswood sewage lagoon does not have plants, and when liquid effluent overflows, it is released into a ditch and ends up flowing into Lake Winnipeg.
  • Septic fields
    • Liquid waste goes into the fields.
    • These are not inspected and there are no regulations for them in Manitoba.
  • Detergents in sewage effluent
    • Many detergents don’t have phosphorous, but some heavy cleaning products do.
  • “Dirty Little Secret”
    • Phosphorous is deliberately added to municipal water supplies in order to mitigate the leaching of lead from the water distribution system (orthophosphate)

 Agriculture

Fertilizing with manure
  • Factory Farming
    • Hog barns amidst wetlands produce four times as much waste as humans. The untreated raw waste is stored in tanks which tend to break , or in pits lined with one metre of clay.  In the fall, the stored sewage is emptied and sprayed onto fields.  
    • There is no such thing as a leak-proof lagoon. 
    • Cattle and turkey farms are a problem as well. 
  • Illegal manure dumping
    • Manure is taken out of the lagoon and dribbled with a truck onto municipal roads.
  • Direct barn drainage to ditches, or runoff into streams and ditches (you can smell it)
    • Hog manure in Hazel Creek flowing into Agassiz Provincial Forest
    • Manure into a wildlife refuge in Fisher Branch. 
    • Fall/winter manure applications on Brokenhead land for crops; the spring melt carries the manure away to the Brokenhead River. 

Manufacturing Industries/ Others

  • Spills from slaughtering plants
  • Livestock deaths on farms
    • Carcasses are incinerated or buried on the farm, illegally dumped in landfills, ditches and water.
    • Mass mortalities from disease or fire are interred in situ (thousands of animals).  They are bulldozed right there.
  • Landfills
    • Carcasses, pet waste, garden and yard clippings, kitchen waste, hospital waste, chemical containers, degradation of products of synthetic solids. 
  • Cemeteries
    • When located on the banks of streams and rivers, they are subject to erosion, landslides and flooding.
  • Logging/Pulping
    • Increase erosion and nutrient leaching into lakes and streams (east side of Lake Winnipeg)
    • Pulp mills contain concentrated organic matter rich in nitrogen and phosphorous.
  • Forest Fires
    • Ash is rich in soluble nitrogen and phosphorous compounds.
  • Mining
    • Cyanide used in gold extraction is rich in nitrogen.
  • Smelting
    • Wind carries the pollutants (e.g. in Thompson)
  • Hydro Electric Dams
    • The increased time water stays stagnant results in nutrients persisting longer instead of being flushed through the system.
    • There is nutrient pooling at the north end of the lake.
Overland flooding in St. Andrews
  • Flooding and runoff
    • All barn lagoons, manure storage and crop lands are affected.
    • The 1997 flood resulted in increased levels of nitrogen and phosphorous.
    • Carcasses, stubble burns, chemical fertilizers are extremely soluble in water and a big rain will wash them out.
    • Chemicals rush off fields and into the lake during spring melts. No one is concerned about farmers who fertilize after a crop is off.
    • A picture was shown of cropland runoff that caused blue-green algae in adjacent ditches in October. Nothing should be growing at that time.
  • Cottages and Recreation
    • A cottage owner at Grindstone Point shot out their holding tank so it would drain into the soil as it was too expensive to have it removed.
    • A picture was shown of a cottage owner at Victoria Beach shampooing a dog in the lake 20 metres from the intake for drinking water.
  • Municipal drainage practices
    • More drainage is going into bigger culverts.
  • Agricultural chemical storage facilities

Effects of Algae

  1. Blue-green Algae
    • Shading: nothing grows underneath
    • Oxygen depletion
    • Destabilization and death of aquatic communities
    • Production of toxins which affect humans: neurological, hepatic, lipopolysaccharide toxins.
  2. Cyanobacteria
    • 50 – 70% produce toxins.
    • They are able to move around and are typical of water that is eutrophic
  3. Microcystins
    • These toxins are lethal to humans and animals.
      • They cause circulatory collapse and pooling of blood in the liver.
      • Symptoms are fever, diarrhea, nausea, vomiting and liver hemorrhaging.
      • There is no antidote.
  4. BMAA
    • Linked to neurodegenerative disease (Parkinsons)

When Blooms Wash up on the Shore

• Decrease ingestion, contact or inhalation
• Do not swim
• NEVER handle
• Keep kids and pets away
• Don’t be downwind, once you smell it you are exposed
• Wash hands
• Never apply copper sulphate
• Toxins can persist after you can’t see the blooms.

What can we do today?

  • Avoid products containing phosphorous (buy phosphate-free detergents).
  • Forgo the cottage: two environmental footprints with a cottage and a house.
  • Shift time: fertilizer and manure.
  • Increase monitoring and enforcement—our wetlands are being destroyed.
  • Push for more legislation.
    • We know who the major offenders are. Yet governments don’t do anything, despite saying they recognize the issue.
    • Our bureaucrats may produce nice reports, but the targets they set are not enforced.

These notes are but a sample of Dr. Pip’s talk  She was amazing! I am certainly going to start checking labels after hearing her. 

We were truly privileged to have her speak at our September gathering. Thank you Dr. Pip!

Hope to see you all at our next meeting.

Leave a Reply