Transcript Water pollution – the final chapter

Sediment and heat pollution, and invasive species
WATER POLLUTION – THE FINAL CHAPTER
THREE OTHER TYPES OF WATER POLLUTION
Sediment pollution (too much soil getting into the
water)
Thermal pollution (water that is too warm getting
into a lake or river)
Invasive species (species that don’t belong take
over)
LET’S START WITH SEDIMENT POLLUTION
What is sediment?
It is loose sand, clay and silt, and some organic
matter (dead leaves, branches, etc.) that is
washed or blown away.
LET’S START WITH SEDIMENT POLLUTION
Where does this soil/sediment come from?
Mostly from agriculture (erosion of soil from farm
fields or animals drinking directly from water
body) and some from clearcutting forests
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LET’S START WITH SEDIMENT POLLUTION
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What is the problem with sediment pollution?
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LOTS!
animals that live in the water can be affected
(e.g. fish’ gills get clogged).
 If soils carries nutrients, it could lead to algal
blooms
 Could block sunlight to aquatic life
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SEDIMENT POLLUTION
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What can be done about it?
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Plant tree/shrub ‘buffer’ strip between farms
and a body of water

Plant grasses on bare soil fields
THERMAL (HEAT) POLLUTION
What is it?
A lowering of water quality due to the addition of
hot or cold water that will change the
temperature of the body of water.
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THERMAL POLLUTION
Where does thermal pollution come from?
Mostly from power plants that need water to cool
equipment. After the water is used it can be
released into lakes and rivers.
AND MORE ABOUT THERMAL POLLUTION
What’s the problem? When the returned water is
hotter?
 Decrease in oxygen
 Increased hunger and activity in fish and other
water (aquatic) animals – they will eat more
 Reproduction problems
 Bacteria and algae can grow fast
AND MORE ABOUT THERMAL POLLUTION
What’s the problem? When the returned water is
COLDER?
Could stop reproduction completely
Could cause extinction of certain sensitive fish
species
THERMAL POLLUTION – FINAL THOUGHT
What can be done to prevent it?
Require power plants to use very efficient cooling
Encourage people to use less energy – that
means less power for power plants to produce.
Other ideas?
AND THEN THERE ARE INVASIVE SPECIES
What is it?
An invasive species is not from here and once it
is here it is likely to hurt the ecosystem. Often
they have nothing that eats them so they can
multiply like crazy!
INVASIVE SPECIES
What is the problem? Invasive species can:
Can make other native species go extinct (gone
forever!)
Can reduce biodiversity
Can cost a lot of money to deal with (i.e. zebra
mussels)
INVASIVE SPECIES…..
Some examples:
Sea lampreys – now much less but caused the
collapse of the Great Lake trout and whitefish
fisheries in the 1950s. They suck bodily liquids
out of other fish.
INVASIVE SPECIES
Another example – zebra mussels
Came in with international ships, they spread
rapidly and grow on docks, boats, fishing nets,
pipes, etc. they also make the water cloudy…
INVASIVE SPECIES
What can be done?
Depends on the species – fish can be fished,
plants can be physically removed
Difficult and usually expensive!