This document discusses several key factors that influence water quality: temperature, dissolved oxygen, pH, nitrogen, phosphates, turbidity, and bio-indicators. It provides details on how each factor is measured and affected by human and natural influences. For example, it explains that temperature impacts dissolved oxygen levels and organism stress, while excess nitrogen and phosphates can cause eutrophication and lower dissolved oxygen. Turbidity measures water clarity and is increased by sediments, and bio-indicators can help assess water health through presence of different organisms.

1. TEMPERATURE
DISSOLVED
OXYGEN (DO)
pH NITROGEN
PHOSPHATES
TURBIDITY
BIO-
INDICATORS
Water Quality Factors

2. Water Quality – Guided Notes
- pH level
- temperature (thermal pollution)
- turbidity
- bio-indicators
- dissolved oxygen
- salinity
- phosphates and nitrates (Phosphorous and
Nitrogen)

3. Water Quality – Dissolved oxygen
- The amount of oxygen (yes the gas)
dissolved into water. It gets there by rapid
movement of water, diffusion, and as a
byproduct of photosynthesis!

4. Water Quality – Salinity
How much salt is
in water, should
know this.
PPT means parts
per thousand.
For example, if in
1000 grams of
water, there are
30 grams of salt,
it’s ocean water!

5. Water Quality – Thermal pollution
- Changing the water quality by adding
heated water to a non-heated water source.

6. 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.

7. 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)

8. Temperature affects the oxygen-
carrying capacity of water.
Rapid temperature change and
temperature extremes can stress
aquatic organisms.
As the water warms, the
amount of dissolved
oxygen decreases.
14 Dissolved Oxygen (ppm)
12
10
8
6
4
____________________________________
Winter Summer

9. DISSOLVED OXYGEN (DO)
ORANGE =
Oxygen
MICKEY
MOUSE =
Water
Fish need
Oxygen
Less Oxygen =
Less fish

10. 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

11. ORGANIC WASTE = LOW DO
• Organic waste = parts of once living things
EXAMPLES OF ORGANIC WASTE:
Sewage
Farm runoff
Discharge from food processing plants

12. 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 & sewage-
filled water.

13. HEALTHY POND

14. RAW SEWAGE IS DUMPED

15. UNHEALTHY POND

16. Water Quality – pH level
- pH stands for the potential of Hydrogen in
water.
- Here’s the pH scale:

17. pH
• pH = measure of concentration of
hydrogen ions in a substance
• Tells whether substance is:
ACID
BASE
NEUTRAL

18. 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

19. pH
US Northeastern rain pH =
4.3
Rain elsewhere in US pH =
5.0 – 5.6

20. pH

22. ALKALINITY
Alkalinity refers to the water’s
ability to neutralize acids.
Alkalinity is
produced by
minerals such as
limestone.
Limestone is a type of ocean
sediment composed of calcium
carbonate.

23. Limestone bedrock areas often
have caves and sinkholes, known
as Karst.
Water with low
alkalinity is
usually
acidic.

24. Ammonia
Ammonia is produced by the
decay of organic matter and
animal waste.
Ammonia is toxic to most
aquatic life, especially at high
pH.
Bacteria readily convert
ammonia to nitrate.
(a plant nutrient)

25. Ammonia
Ammonia is
a form of
nitrogen
and part of
the
Nitrogen
Cycle.

26. 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

27. Water Quality – Phosphates and Nitrates
- Runoff, fertilizer, eutrophication...

28. 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

29. NITROGEN
SOURCES OF NITROGEN IN WATER:
Human & animal waste
fertilizer
EFFECTS OF TOO MUCH NITROGEN:
Lowers dissolved oxygen (DO).

30. 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

31. NITROGEN
OUR HAPPY POND IS
NOW “DEAD”

32. NITRATES

33. 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

34. PHOSPHATES
SOURCES OF PHOSPHATES IN WATER:
Storm sewer runoff
Soil erosion
Fertilizer
Forest fires
Volcanic eruptions

35. PHOSPHATES

36. PHOSPHATES
EFFECTS OF PHOSPHATES:
Eutrophication (same as with nitrates)

37. PHOSPHATES
OUR HAPPY POND IS
NOW “DEAD”

38. PHOSPHATES

39. Water Quality – Turbidity
- Turbidity is how cloudy a substance is,
basically. Which picture is more turbid?
- Which would you rather swim in…?

40. TURBIDITY
Turbidity refers
to water clarity.
Sediments
suspended in
the water
increase
turbidity.

41. TOTAL SUSPENDED SOLIDS
(TSS)
TSS is the measure of the
sediment suspended in the
water.
TSS is related to turbidity.
Water with high TSS usually has
high Total Dissolved Solids (TDS)
as well.

42. A secchi disk is one type of
instrument used to measure
turbidity.

43. TURBIDITY

44. TURBIDITY
• Measures clearness of
water
• Murky water = greater
turbidity
• Caused by solids
blocking sunlight
• Measured using a
Secchi disk or turbidity
meter

45. TURBIDITY
HUMAN DUMPING:
Clay
Silt
Industrial waste
Raw sewage
SOURCES:
Human dumping
Construction
Soil erosion
Nitrate pollution
Phosphate
pollution

46. TURBIDITY
EFFECTS:
Clogs fish gills
Smothers eggs
Makes water unlivable

47. 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

48. Definition: Bio-indicators
 Bio-indicators: macroinvertibrates found living in
water (they tend to remain in one place) that are
sensitive to pollution

49. BIO-INDICATORS

50. Levels: Bio-indicators
 High level of variety: healthy water source
 Small level of variety: poor water source (indicator of
high levels of pollution)

51. Causes: Bio-indicators
 Causes of changes in bio-
indicators:
Pollution that results in
changes in pH,
temperature, dissolved
oxygen, or nitrate levels

52. Results: Bio-indicators
 Results of few varieties of bio-indicators present: the
lack of a large number of different varieties of bio-
indicators is indicative of pollution

53. BIO-INDICATORS
HOW HUMANS AFFECT
BIO-INDICATORS:
Over-fishing
Industrial pollution
Poor farming practices
Adding foreign species

54. BIO-INDICATORS

55. TOXIC CHEMICALS
Toxic chemicals usually come
from industry and energy
production.
The effects are often not known
until years after they have entered
the environment.

56. Toxic chemicals include
heavy metals (lead,
mercury), organic
compounds (DDT, PCB),
inorganic substances
(arsenic) and others.