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2010 Shoal Lake water quality test results

Image of Shoal Lake inletOur staff test Shoal Lake and the intake at the west end of Indian Bay (where the water enters the aqueduct) as part of our routine water quality testing program.

For more information on Winnipeg's drinking water and our impact on Shoal Lake, visit the web page on Shoal Lake - Our Water Source.

Testing

We take samples at the intake every week during the open water season and every two weeks during the rest of the year. We also take samples from the Shoal Lake watershed from May to October. We test the intake samples for:

  • routine water chemistry
  • taste and odour compounds
  • metals
  • disinfection by-products
  • bacteria and protozoa
  • toxins produced by algae

By taking these samples, we track seasonal changes in water quality and determine the effects (if any) of human activity within the Shoal Lake watershed.

Water entering the aqueduct intake passes through screens before being treated by chlorine on a periodic basis for slime and Zebra mussel control. The aqueduct brings water to Deacon Reservoir before entering the Water Treatment Plant. There, we test both the raw and treated water samples before the water is distributed to Winnipeg homes and businesses.

What is being measured How it's measured Guideline or regulation Shoal Lake average Shoal Lake range Comments
Odour units Inoffensive 112 50 to 200 Raw water - guideline does not apply
Geosmin parts per trillion no guideline 4.4 <0.5 to 9.2 Common taste and odour compound
IPMP - 2-isopropyl-3-methoxypyrazine parts per trillion no guideline <0.5 <0.4 to <0.5 Common taste and odour compound
IBMP - 2-isobutyl-3-methoxypyrazine parts per trillion no guideline <0.5 <0.4 to <0.5 Common taste and odour compound
MIB - 2-methylisoborneol parts per trillion no guideline <2.0 <0.6 to 2.5 Common taste and odour compound
246 TCA - 2,4,6-trichloroanisole parts per trillion no guideline <0.5 <0.5 to <1.0 Common taste and odour compound
236 TCA - 2,3,6-trichloroanisole parts per trillion no guideline <0.5 <0.5 to <1.0 Common taste and odour compound
345 TCV - 3,4,5-trichloroveratrole parts per trillion no guideline <0.5 <0.4 to <0.5 Common taste and odour compound
MTBE - methyl tertiary-butyl ether parts per million no more than 0.015 <0.0005 <0.0005 to <0.0005 Raw water - guideline does not apply
NDMA - N-nitrosodimethylamine parts per billion under review 0.002 0.0007 to 0.005 Guideline under review by Health Canada
Plankton (algae) count cells/mL no guideline 56,415 1,500 to 335,800 Algae contribute to odours and may cause filter clogging
Chlorophyll-a parts per billion no guideline 7 <1 to 29 Chlorophyll is found in algae
Microcystin LR parts per billion no more than 1.5 <0.2 <0.2 to <0.2 Raw water - guideline does not apply
Cryptosporidium oocysts per 100 litres no guideline <1 <1 to <1 14 samples taken in 2010 - no positive results
Giardia cysts per 100 litres no guideline <1 <1 to <1 14 samples taken in 2010 - no positive results
Turbidity (clearness) Nephelometric turbidity units no guideline 1.48 0.25 to 8.10  -
Colour, Apparent Apparent colour units no guideline 5.0 2.5 to 15.0  -
Total Solids parts per million no guideline 100 80 to 126  -
Total Dissolved Solids parts per million no more than 500 90 75 to 111 Raw water - guideline does not apply
Conductivity microsiemens per centimetre no guideline 148 134 to 166 Another measure of dissolved solids
pH units between 6.5 and 8.5 8.16 7.61 to 8.87 Raw water - guideline does not apply
Temperature degrees Celcius no more than 15 9.3 2.0 to 22.7 Raw water - guideline does not apply
Total Alkalinity parts per million as calcium carbonate no guideline 72 62 to 80  -
Total Hardness parts per million as calcium carbonate between 80 and 100 73 66 to 82 Raw water - guideline does not apply
Total Organic Carbon parts per million no guideline 10 7 to 17  -
Soluble Organic Carbon parts per million no guideline 10 7 to 14  -
Total Kjeldahl Nitrogen (TKN) parts per million no guideline 0.50 <0.20 to 0.90 TKN is a combination of ammonia and organic nitrogen
Total Phosphorus parts per billion no guideline 12 2 to 24 Phosphorus can contribute to algae growth
Dissolved Reactive Phosphorus parts per billion no guideline 1 <1 to 3  -
Fluoride parts per million no more than 1.5 <0.08 <0.08 to 0.09 Raw water - guideline does not apply
Nitrate Nitrogen parts per million no more than 10 0.009 <0.003 to 0.031 Raw water - guideline does not apply
Chloride parts per million no more than 250 2.1 1.2 to <9.0 Raw water - guideline does not apply
Sulfate parts per million no more than 500 3.4 1.0 to 9.4 Raw water - guideline does not apply
Trihalomethanes parts per billion no more than 100 <0.5 <0.5 to 1.1 Raw water - guideline does not apply
Haloacetic acids parts per billion no more than 80 <10 <5 to <10 Raw water - guideline does not apply
Aldehydes parts per billion no guideline <2 <2 to 5  -
Calcium parts per million no guideline 19.8 18.1 to 21.4 Contributes to hardness
Magnesium parts per million no guideline 5.5 5.3 to 5.7 Contributes to hardness
Sodium parts per million no more than 200 2.0 1.9 to 2.1 Raw water - guideline does not apply
Potassium parts per million no guideline 1.2 1.1 to 1.3 Raw water - guideline does not apply
Iron parts per million no more than 0.3 <0.01 <0.01 to 0.05 Raw water - guideline does not apply
Copper parts per million no more than 1.0 <0.001 <0.001 to 0.002 Raw water - guideline does not apply
Lead parts per million no more than 0.010 <0.001 <0.001 to <0.001 Raw water - guideline does not apply
Aluminum parts per million no more than 0.1 <0.001 <0.001 to 0.003 Raw water - guideline does not apply
Antimony parts per million no more than 0.0006 <0.02 <0.001 to <0.02 Raw water - guideline does not apply
Arsenic parts per million no more than 0.010 <0.001 <0.001 to <0.001 Raw water - guideline does not apply
Nickel parts per million no guideline <0.001 <0.001 to <0.001  -
Chromium parts per million no more than 0.05 <0.001 <0.001 to 0.005 Raw water - guideline does not apply
Boron parts per million no more than 5 0.013 0.010 to 0.025 Raw water - guideline does not apply
Cadmium parts per million no more than 0.005 <0.001 <0.001 to <0.001 Raw water - guideline does not apply
Manganese parts per million no more than 0.05 0.008 0.002 to 0.014 Raw water - guideline does not apply
Uranium parts per million no more than 0.02 <0.001 <0.001 to <0.001 Raw water - guideline does not apply
Zinc parts per million no more than 5.0 <0.002 <0.001 to <0.003 Raw water - guideline does not apply
Zirconium parts per million no guideline <0.001 <0.001 to <0.001  -
Mercury parts per million no more than 0.001 0.0000013 <0.000001 to 0.0000017 Raw water - guideline does not apply

Guidelines from 'Summary of Guidelines for Canadian Drinking Water Quality' by Health Canada, revised February 1, 2011.

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Last updated: June 29, 2018

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