A.Zahid By HAMEEDA RASHEED INSTITUDE OF SCIENCE AND TECNOLOGY

1. Water
Resources and
Pollution

2. Importance of Water
➝ Found in every living organism.
➝ Dissolves and transports many molecules (nitrates,
phosphates, minerals).
➝ Quickly moves between three phases, transferring it
(and heat) between the surface, atmosphere, and
around the planet.
2

3. 3
Ocean
97%
Freshwater
Surface Freshwater
Ice Caps and Glaciers
70%
Groundwater
(Aquifers) 29%
Soil Moisture 38%
Water Vapor
8%
Living Organisms
1%
Rivers
1%
Lakes
52%
Distribution of
Water

4. Hydrologic Cycle
Movement processes of water.
4

5. 5
Evaporation
Liquid water
is heated and
converted to
water vapor.
Condensation
Water vapor
cools and
liquifies.
Precipitation
Water droplets
combine and fall
from clouds.
Runoff
Flows downhill to
a stream, then a
lake or ocean.
Transpiration
Evaporation
from leaves.
Infiltration
Seeps through
spaces in soil.

6. What water
cycle
process is
6

7. What water
cycle
process is
7

8. What water
cycle
process is
8

9. What water
cycle
process is
9

10. Importance of Water
➝ Aquifers are
underground
formations of
rock and sand
that hold water.
➝ The uppermost
boundary of
aquifers is
called the water
table.
10

11. ➝ An unconfined
aquifer is
recharged from
the ground
surface directly
above it.
➝ A confined
aquifer has an
impermeable
layer of clay or
rock that limits
recharging to a
11

12. A watershed
is the entire
area of land
where water
runoff or
infiltration
feeds a 12

13. Water Use
Withdrawal and consumption of water for agriculture, drinking,
etc.
13

14. Using Water
Withdrawal
Amount of water
diverted or removed
from its source. A
portion may be
returned afterwards.
Example: Power plant
coolant water
Consumption
Water withdrawn AND
permanently removed
from a source.
Example: Irrigation
14

15. ➝ The three largest
demands for water
withdrawal include:
⇾ Power generation:
Coolant water and for
generating steam.
⇾ Irrigation: Watering
crops.
⇾ Domestic: Household
water uses.
15

16. ➝ Irrigation is the
largest consumer of
water worldwide, as
most of it is either
taken in by plants or
evaporated into the
atmosphere.
16

17. ➝ Water stress
occurs when
the demand for
water is greater
than the
supply.
⇾ Leads to
depletion of
freshwater
resources.
17

18. ➝ Regions with
water stress
tend to be:
⇾ Naturally arid
⇾ Heavily
populated
⇾ Growing
water-
intensive
crops and
animals.
18

19. ➝ Environmental
impacts of
overconsumption
of freshwater
supplies:
⇾ Decrease in river
flow.
⇾ Lowering of lake
and reservoir levels.
⇾ Subsidence, or the
gradual sinking of
land.
19

20. Cone of Depression
Lowering of water
table around a well.
Saltwater Intrusion
Freshwater depletion causes the movement of saltwater into freshwater aquifers.
Well
Well
Contaminated with saltwater.
Salt
water
Cone of
Depression

21. Water Conservation
Alternative water sources and reducing water consumption.
21

22. ➝ Desalination is the removal of salt from ocean water, through
two possible methods:
⇾ Distillation boils the water and collects the steam.
⇾ Reverse osmosis passes pressurized water through a filter.
22

23. Desalination
produces a lot of
salt waste called
brine.
23
The energy costs
for desalination are
very high.

24. ➝ Water conservation efforts
focus on agriculture, as it is
the biggest source of water
consumption.
⇾ Installing drip irrigation
systems for tree crops with
high water demands.
⇾ Contour plowing and
terracing to slow runoff and
increase infiltration.
⇾ Lining irrigation canals to
prevent leaks and block
evaporation.
24

25. Home water
conservation
centers
around high-
efficiency
devices.
25
Dual-flush toilets use
less water for urine
and more for solid
waste.
Low-flow
showerheads and
faucets use aerators
to reduce water
consumption.

26. Efficient dishwashers and
washing machines run longer,
but use much less water per 26

27. Xeriscaping
uses drought-
tolerant plants in
the homes and
yards in arid
climates. 27

28. ➝ Graywater systems recirculate used water from the sink or
shower into the toilet or for yard irrigation.
28

29. Water Pollution
Alternative water sources and reducing water consumption.
29

30. From the industrial
revolution until the
passage of the
Clean Water Act in
1970, surface
waters were used
as industrial dump
sites.
30

31. The Clean Water
Act established
rules and
regulations for
what can be
discharged into
surface waters. 31
The EPA lists
all impaired
waters that do
not meet one or
more of the
standards.

32. Causes of impaired waters
Coliform
Bacteria
Disease-causing
bacteria from
untreated human
sewage and
manure.
Heavy Metals
Neurotoxins.
Released by
mining and the use
of synthetic
fertilizers.
Persistent
Organic
Pollutants
(POPs)
Synthetic
chemicals that do
not degrade and
are prone to
biomagnification
and
bioaccumulation.
“Forever
chemicals.”
32
Oxygen-
Depleting
Pollution
Biodegradable
matter consumed
by decomposers,
who deplete
oxygen levels in
Nutrient
Pollution
Nitrogen and
phosphorous-rich
compounds that
promote algae
overgrowth.

33. 33
Point source water
pollution comes from
single, identifiable
source.
➝ Factories
➝ Water treatment plants
Factory
Water
Treatment

34. 34
Nonpoint source water
pollution comes runoff or
infiltration from a wide
area.
➝ Agricultural fields
➝ City stormwater drains
➝ Home septic systems
Septic
Systems
City stormwater runoff Agricultural
- Manure
- Fertilizer
- Pesticides

35. ➝ Cultural eutrophication
is an increase in algae
growth as fertilizer enters
surface waters.
⇾ Elevated nitrates and
phosphates promote algae
overgrowth.
⇾ Algae block sunlight, killing
submerged plants.
⇾ As the algae die,
decomposers use up the
dissolved oxygen in the water.
35

36. Oligotrophic
Fish
More fish and zooplankton
• low nutrients
• low turbidity
• high sunlight
Benthos
Submerged
Plants
Zooplankton
Mesotrophic
• Increasing nutrients,
turbidity, and algae
• Decreasing sunlight
• High nutrients
• High turbidity
• Hypoxia, reduced
dissolved oxygen
Hypoxia
Death of submerged plants and benthos
Eutrophic Hypereutrophic
Anoxia
No fish, only plankton.
• High nutrients
• High turbidity
• Anoxia, absence of
dissolved oxygen.

37. ➝ Dead zones are any areas of water where the dissolved
oxygen is too low for fish and other large animals to survive.
Causes:
Cultural
eutrophication
Sudden
increase in
water
temperatures
Disruption in
normal oxygen
mixing

38. ➝ Explain why the 3
C’s rule exists for
Lake Michigan Fish:
⇾ Choose fish that are
primary consumers
and not bottom
feeders.
⇾ Clean fish for eating
by removing as
much fat as
possible.
⇾ Cook fish on a grill
38

39. Drinking Water Regulations
Safe Drinking Water
Act (EPA)
Sets limits and testing
requirements for
contaminants in municipal
tap water.
Does not apply to non-
municipal well water or
bottled water.
Food, Drug, and
Cosmetic Act (FDA)
Generally fewer testing and
contaminant requirements
than tap water.
Water must be classified --
Artesian: Confined aquifer
Mineral/Spring: Unconfined
aquifer
Purified: Tapwater
39

40. Ocean Pollution
Oil and plastics.
40

41. ➝ In 1989, the Exxon Valdez oil tanker ran aground in Alaska,
causing the greatest oil spill up to that point.
➝ The Oil Pollution Act of 1990 required tankers to have a
double-hull design by 2015 and increased the legal liability of
oil companies for spills. 41

42. ➝ In 2010, the Deepwater Horizon oil rig experienced a blowout
and explosion, then leaked oil for about 3 months.
➝ No laws passed in response; a new executive branch agency
was created to oversee offshore drilling.
42

43. Impacts of oil spills
Mammals
Penetrates their
fur, causing
hypothermia in
cold waters.
Birds
Penetrates
feathers,
preventing flight
and causing
hypothermia.
Fish and
Plankton
Oil is directly toxic
to them.
43
Benthos
If dispersants are
used, oil sinks to
the bottom of the
sea and suffocates
benthic
communities.
Coastal
Ecosystems
Oil washes up on
shore, polluting
beaches and wetlands.

44. ➝ The ocean is also heavily
polluted with plastics
released from ships and
rivers that flow into the
ocean.
⇾ Dead beached whales are
commonly found with
stomachs full of plastic bags.
44

45. ➝ Plastics are not biodegradable but will break down into
smaller pieces as they are exposed to sunlight, forming
tiny microplastics.
45

46. 46
➝ Microplastics bioaccumulate in
fish and shellfish, then
biomagnify through the food

47. ➝ There are five major circular currents called gyres that plastic
pollution accumulates in.
47

48. Watch the first 4 minutes of this clip
about the Great Pacific Trash
Vortex.
What gyre is it in?
Why is the plastic not visible from
the surface?
How much is there?
48

49. The Ocean Cleanup has developed a trawl net to skim plastic from the
gyre.
49
A test run captured about 10 tons out of an estimated 79,000 tons.