Transcript Water Quality PPT - Mrs. Meadows Science

Water Quality Factors
TEMPERATURE
TURBIDITY
DISSOLVED
OXYGEN (DO)
PHOSPHATES
BIOINDICATORS
pH
NITROGEN
TEMPERATURE
EFFECTS:
changes rate of photosynthesis
changes rate of respiration
changes DO in water
cold water holds more DO
hot water holds less DO
changes sensitivity of organisms to toxic
waste, parasites, disease.
TEMPERATURE
• Thermal pollution = adding warm water to
cold water.
CAUSES OF THERMAL POLLUTION:
• Industry (nuclear power plants, paper
mills)
• Urban Development (storm water runoff,
construction, soil erosion)
DISSOLVED OXYGEN (DO)
ORANGE =
Oxygen
MICKEY
MOUSE =
Water
Fish need
Oxygen
Less Oxygen =
Less fish
DISSOLVED OXYGEN (DO)
TO INCREASE DO:
• Much of DO comes from atmosphere
• Some of DO comes from photosynthesis
TO DECREASE DO:
• Add pollution
• Add organic waste
ORGANIC WASTE = LOW DO
• Organic waste = parts of once living things
EXAMPLES OF ORGANIC WASTE:
Sewage
Farm runoff
Discharge from food processing plants
HOW RAW SEWAGE LOWERS
DO
RAW SEWAGE GOES INTO WATER:
1. Decomposers chow down
2. Decomposers take up oxygen
3. Decomposers reproduce, taking up more
oxygen
4. No more oxygen for other animals
5. Nothing left but decomposer & sewagefilled water.
HEALTHY POND
RAW SEWAGE IS DUMPED
UNHEALTHY POND
pH
• pH = measure of concentration of
hydrogen ions in a substance
• Tells whether substance is:
ACID
BASE
NEUTRAL
pH
Measured on scale from 0 to 14
0 = highly acidic (HCl)
7 = neutral (pure water)
14 = highly basic (bleach)
Seawater pH ranges from 7.5 – 8.5
Average pH of ocean water = 7.8
pH of natural water = 6.5 – 8.5
Optimal range for life = 6.5 – 8.2
pH
US Northeastern rain pH =
4.3
Rain elsewhere in US pH =
5.0 – 5.6
pH
pH
SOURCES OF LOW pH IN WATER:
• Acid rain is cause of acid in
thousands of lakes
• Burning fossil fuels has increased
acid rain
EFFECTS OF LOW pH IN WATER:
• Low pH directly kills fish
• pH < 5, most fish eggs die
NITROGEN
• Living organisms need nitrogen to
make proteins
• Nitrates (NO3) & Nitrites (NO2) are
compounds made of nitrogen &
oxygen
• Some nitrogen in water is good
• The wrong amount is bad
NITROGEN
SOURCES OF NITROGEN IN WATER:
Human & animal waste
fertilizer
EFFECTS OF TOO MUCH NITROGEN:
Lowers dissolved oxygen (DO).
NITROGEN – EUTROPHICATION
Q: How does Nitrogen reduce the amount of DO?
A: Eutrophication
• Nitrogen feeds algae (green stuff)
• Algae grows & grows
• Algae blocks sunlight
• Underwater plants die
• Algae die and decompose
• The decomposition takes up oxygen
• No DO for organisms, so they die
NITROGEN
OUR HAPPY POND IS
NOW “DEAD”
EUTROPHICATION
NITRATES
PHOSPHATES
• Phosphorus is an element like hydrogen
or oxygen
• Phosphorus combines with other things to
make phosphates
• Essential for living things
• Usually present in very small amounts
• Too much is bad
PHOSPHATES
SOURCES OF PHOSPHATES IN WATER:
Storm sewer runoff
Soil erosion
Fertilizer
Forest fires
Volcanic eruptions
PHOSPHATES
PHOSPHATES
EFFECTS OF PHOSPHATES:
Eutrophication (same as with nitrates)
PHOSPHATES
OUR HAPPY POND IS
NOW “DEAD”
EUTROPHICATION
PHOSPHATES
TURBIDITY
• Measures clearness of
water
• Murky water = greater
turbidity
• Caused by solids
blocking sunlight
• Measured using a
Secchi disk or turbidity
meter
TURBIDITY
TURBIDITY
SOURCES:
Human dumping
Construction
Soil erosion
Nitrate pollution
Phosphate
pollution
HUMAN DUMPING:
Clay
Silt
Industrial waste
Raw sewage
TURBIDITY
EFFECTS:
Clogs fish gills
Smothers eggs
Makes water unlivable
BIO-INDICATORS
• Bio-indicators = organisms that help
determine health of water.
• Presence or absence tells something
about the water.
• Not always an accurate way to measure
water quality.
• Accurate in telling environmental stress
BIO-INDICATORS
HOW HUMANS AFFECT
BIO-INDICATORS:
Over-fishing
Industrial pollution
Poor farming practices
Adding foreign species
BIO-INDICATORS
BIO-INDICATORS