Water Quality:

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Water Quality The Basics NSTA Regional
Conference Omaha, Nebraska October 19th, 2005
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• Why is Water Quality Important?
• Effects all humans
• Safe drinking water
• Allows for food productions and SAFE food
  products
• Effects Wildlife
• Health domestic and wild animals
• Diversity of Life (insects or
• macroinvertebrates)
• Recreation
• Swimming
• Water Sports
• Fishing

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• What determines the Quality of Water?
• Individual test parameters
• pH
• Temperature
• Dissolved Oxygen
• Clarity
• Turbidity
• Secchi
• Total Nitrogen
• Total Phosphorus
• Salinity
• Alkalinity

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pH pH Negative logarithm of the hydrogen ion
concentration pH -log H
H OH- OH- OH- H OH- H H H OH-
H H H OH- H H OH- OH-
H H H
Each whole pH below 7 is ten times more acidic
than the next higher value. For example, a pH of
4 is ten times more acidic than a pH of 5. The
same holds true for pH values above 7. Each value
above 7 is ten times more basic than the next
lower pH value.
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• Temperature
• Important because
• Dissolved Oxygen
• Temperature Dissolved Oxygen
• -Decreases in Dissolved Oxygen can cause
  problems
• for wildlife (ex. fish kills)
• Fluctuations can cause problems for many plants
  which moves up the food web.

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Dissolved Oxygen A measure of free O2 (gas) in
the water. lt5 ppm dangerous zone 5 10 ppm
adequate zone gt10 ppm good
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Clarity Turbidity A measure of the suspended
solids, which reduce the transmission of light
through scattering or absorption. Secchi Measur
ing how far down a person can see the secchi
disk. Somewhat objective, but fairly accurate.
Easy to discuss results among non-scientists.
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• Nitrogen
• Nitrogen is a nutrient, like calcium or
  potassium.
• Nitrogen is available in the environment
  naturally.
• The problem is when more is added fertilizers
• or confinements.

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Phosphorus

• Phosphorus is also a nutrient, like nitrogen,
  calcium,
• or potassium.
• It is also available in the environment
  naturally, but
• phosphorus is more limiting in freshwater
  ecosystems.
• Adding too much phosphorus (making it no linger
  limiting)
• can cause algal blooms.

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• Salinity
• A measurement of the salt content in the water
• lt 5 psu freshwater
• gt 5 psu brackish water
• gt 32 psu sea water
• Not necessarily table salt (NaCl)
• - Examples of salts sodium calcium magnesium,
• potassium, sulfate, and chloride.
• - All dissolved from geologic materials
• rocksthe bottom of the lake.

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• Conductivity
• A measure of the electromagnetic charge of the
  water.
• Measures the electrical charge between two
  electrodes (metal rods) in the water.
• -For there to be an electrical charge, there
  must be free ions or dissolved salts (TDS).
• -The higher the TDS or free ions, the
  more electrical current that can occur,
  causing higher conductivity.

134 uS
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• Alkalinity
• The ability of a lake (or body of water) to
  buffer from
• changes in pH.
• Causes in changes in pH
• discharge
• plant productivity
• animal waster, processes
• Why is alkalinity important?
• Drastic or constant changes in pH can cause
  problems for the biota of the lakes ecosystem.

ACID
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Questions?