water quality measurement by N1OGt08x


									Water Quality:
  The Basics
   NSTA Regional Conference
      Omaha, Nebraska
      October 19th, 2005
         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

      Water Sports
What determines the Quality of Water?
Individual test parameters:
• pH
• Temperature
• Dissolved Oxygen
• Clarity
• Total Nitrogen
• Total Phosphorus
• Salinity
• Alkalinity
 pH: Negative logarithm of the hydrogen ion concentration

                       pH = -log [H+]

      H+  OH-                            H+ H+ H+
           OH-                            OH-    H+
       OH-     H+                             H+ OH-
     OH-    H+    H+                       OH- H+
       H+      OH-                       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.
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.
      Dissolved Oxygen

A measure of free O2 (gas) in the water.

      <5 ppm – dangerous zone
     5 – 10 ppm – adequate zone
           >10 ppm – good
       A measure of the suspended
       solids, which reduce the
       transmission of light through
       scattering or absorption.

         Measuring how far down a
         person can see the secchi disk.
         Somewhat objective, but fairly
         accurate. Easy to discuss
         results among non-scientists.
•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.
• 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.
• A measurement of the salt content in the water
            < 5 psu = freshwater
            > 5 psu = brackish water
            > 32 psu = sea water

• Not necessarily “table salt” (NaCl)…
       - Examples of salts: sodium calcium magnesium,
         potassium, sulfate, and chloride.

      - All dissolved from geologic materials …
        rocks…the bottom of the lake.

•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
   134 uS            -The higher the TDS or free ions, the
                             more electrical current that can
occur,                       causing higher conductivity.
• The ability of a lake (or body of water) to buffer from
  changes in pH.
• Causes in changes in pH:
      plant productivity
      animal waster, processes
• Why is alkalinity important?
      Drastic or constant changes in pH can cause
      problems for the biota of the lake’s ecosystem.

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