Chemical Pollution

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Chemical Pollution Eutrophication
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Types of chemical pollution found in bodies of
water

• Excess sewage and waste
• Toxic Chemicals (ex mercury/PCBs)
• Fertilizers/Detergents
• Any chemical that alters the chemical balance in
  the body of water

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How do these pollutants enter the bodies of water?

• Runoff of fertilizers from farms and homes.
• Sewage backup from excessive rains.
• Runoff of water from parking lots etc. that does
  not end up in sewage systems.
• Pollution that comes from rainfall. Example
  acid rain

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Eutrophication

• Process of increasing the amount of organic
  matter and nutrients in a lake or body of water.
  
• This is a natural process that occurs over
  thousands to millions of years.
• Sometimes eutrophication is referred to as aging
  of a lake.

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What are eutrophic lakes like?

• Abundant nutrients
• Abundant life algae, fish, and other animals.
• Comparatively shallow
• Lake Erie is the most eutrophic of the Great
  Lakes. It is the most biologically productive.
  More fish are caught in Erie than any of the
  others.

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Sounds like Eutrophication is Good!

• A little eutrophication that occurs in nature is
  normal. But??
• But too much of a good thing is bad!! Man-made
  or cultural eutrophication happens on a much
  faster and larger scale.

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• In the 1960s, Lake Erie was declared "dead,"
  though, ironically, it was full of life -- just
  not the right kind. Eutrophication had claimed
  Lake Erie and excessive algae became the dominant
  plant species, covering beaches in slimy moss and
  killing off native aquatic species by soaking up
  all of the oxygen.

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What causes cultural eutrophication?

• Fertilizers, detergents, and sewage are the types
  of chemical pollution that lead to cultural
  eutrophication.
• These types of pollution have large amounts of
  phosphorus and nitrogen which lead to excessive
  algae growth.

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Return to the Profundal

• The excessive algae out compete most other
  phytoplankton and then die and go to the bottom.
• Excessive decomposition and sedimentation leads
  to large amounts of cell respiration which uses
  up all the oxygen.
• Literally, the excessive algae suffocates most of
  the rest of life in the lake.