Water Resources and Water Pollution Lecture Powerpoint

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Powerpoint presentation given as a lecture to environmental science students studying a unit on water, the water cycle, and water pollution.

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Water: Resources and Pollution

"Water will be more important than oil this century.”
- Former U.N. Secretary General Boutros Boutros Gali
1
Great Plan for the Transformation of Nature

• During the late 1940s, Joseph Stalin
proposed a plan in the Soviet Union
to prevent a repeat of drought-
caused famine in 1947 that killed
nearly a million people.
• A wide variety of ideas were
implemented during the next two
decades.

2
Transformation of Nature

• Windbreaks, or lines of trees, were built to
reduce soil erosion.

A windbreak built into a North Dakota Farm.
Source: Wikimedia

3
Transformation of Nature

• A network of irrigation
canals were built to
divert water from two
rivers into a desert
region, to encourage
the cultivation of crops
such as rice, wheat,
and cotton.
• The rivers normally
fed into the Aral Sea.
4
The Aral Sea

• In the 1950s, the Aral sea
was one of the four
largest lakes in the world,
with an area of 26,300
square miles.
• The entire lake was part
of the U.S.S.R., in the
countries that today are
Kazakhstan and
Uzbekistan.
5
Irrigation Canals

• The irrigation canals were poorly built and
uncovered, allowing about half of the water
to evaporate or leak into the surrounding soil.
• The Aral sea, deprived of its main water
supply, began to shrink in 1961.

Satellite imagery of
the Aral Sea shrinkage
from 1961-2011.

6
Salination

• The amount of water lost by
the Aral Sea would completely
fill Lakes Erie and Ontario.
• The salinity of the remaining
water has increased to 2-3x
that of ocean water.
• The drainage of the lake has An abandoned ship in
Aral, Kazakhstan.
also exposed pesticides,
herbicides, and other
industrial pollutants on the
bottom. 7
Why is Water Important?

• Necessary for all life to exist.
• Next to antibiotics, single biggest increase in
human life span is due to having access to
clean water.
• Diseases/toxins transmitted by contaminated
water:
 Intestinal disease (cholera/dysentery)

 Arsenic poisoning

 Mercury poisoning

8
Hydrologic Cycle

• The water on earth is continually recycled.
• The hydrologic cycle describes this circulation:
1. Water evaporates from wet land, lakes, or

oceans and transpires from plants as they
dry up.
2. Enters the atmosphere, which is much

colder, condenses and falls as
precipitation.
3. Moves underground by infiltration or runs

off into rivers, lakes, or the ocean.
9
10
Earth’s Water Budget

All water

Oceans and
saline lakes
97.4%

Fig. 11-2, p. 238
Earth’s Water Budget

All water

Oceans and
saline lakes
97.4%

Fig. 11-2, p. 238
Earth’s Water Budget

All water Fresh water Readily accessible fresh water
Groundwater
0.592% Biota
0.0001%
Rivers
Lakes 0.0001%
0.007%
Fresh water 0.014%
2.6% Atmospheric
Oceans and Ice caps
Soil water vapor
saline lakes and glaciers
moisture 0.001%
97.4% 1.984%
0.005%

Fig. 11-2, p. 238
MAJOR WATER COMPARTMENTS
• Groundwater
 Largest available (non-frozen) source of fresh

water.
 Water moves underground through infiltration;

percolation through the soil and into fractures
and permeable rocks.
- Zone of Aeration - Upper soil layers that hold

both air and water.
- Zone of Saturation - Lower soil layers where

all spaces are filled with water.
- Water Table - Top of Zone of Saturation

14
Infiltration

15
Groundwater
• Aquifers - Porous layers of sand, gravel, or
rock lying below the water table.
 Aquifers are separate from groundwater;
they are usually isolated by layers of rock.
 Artesian Well – Directly tapes into an
aquifer as a source of water.

16
Groundwater
• The recharge zone is an area where water
infiltrates and refills an aquifer.
 Recharge rate is often very slow,
depending on the size of the recharge
zone and how often it rains there.

17
MAJOR WATER COMPARTMENTS CONT’D

• Wetlands
 Play a vital role in hydrologic cycle.

Wetlands have an unusually high amount
of plant growth. Benefits include:
- Stabilizes soil, preventing erosion

- Slows down surface runoff, allowing

more aquifer recharge.
- Can hold excess water during flooding.

18
MAJOR WATER COMPARTMENTS CONT’D
• Rivers and Streams
 Formed from water that does not infiltrate,
but runs off from surrounding land.
 May also be formed by melting glaciers.

Each of the major
rivers in Southeast
Asia are fed by
Himalayan glaciers.

19
MAJOR WATER COMPARTMENTS CONT’D

• The Atmosphere
 Among the smallest water reservoirs; only

contains 0.001% of the total water supply.
 Has most rapid turnover rate. Water in the

atmosphere does not remain there.
- Redistributes water all over the earth.

20
Water Use

• Consumption – Water that is withdrawn and
no longer available for use because it has
evaporated, been consumed by animals or
plants, or discharged to a different location.

21
Quantities of Water Used
• Water use has been increasing twice as fast
as population growth over past century.
 Worldwide, agriculture claims about 70%
of total water withdrawal.
- In many developing countries,
agricultural water use is extremely
inefficient and highly consumptive.
 Worldwide, industry accounts for about
25% of all water use.
- Cooling water for power plants is single
largest industrial use.
22
Water Withdrawal

23
FRESHWATER SHORTAGES

• Areas that consume more water than
typically falls as precipitation are considered
to have water stress.

24
A Precious Resource

• Currently, 45 countries cannot meet the
minimum essential water requirements of
their citizens.
• Will increase to 60 countries by 2050.

25
Depleting Groundwater

• Groundwater is the source of nearly 40% of
fresh water in the U.S.
• Withdrawing water faster than it can be
replenished leads to a cone of depression in
the water table.
• If this continues, the water table can be
completely withdrawn.

26
Depleting Groundwater

27
Depleting Groundwater Cont’d

• Withdrawing large amounts of
groundwater in a small area causes
porous formations to collapse, resulting in
subsidence.

28
INCREASING WATER SUPPLIES

• Seeding Clouds
• Add silver iodide or dry ice to clouds

• Inconsistent results

29
INCREASING WATER SUPPLIES

• Towing Icebergs
 Cost

• Desalination
 Removal of salt

from ocean water
 Requires a high

input of energy

30
INCREASING WATER SUPPLIES CONT’D

• Dams, Reservoirs, and canals can be
constructed to make the water supply more
consistent or divert water to dry areas.
 This could result in the displacement of

people, flooding of ecosystems.
 Evaporation rates increase as water is

slowed.
 Any dissolved nutrients present in the water

sink into the reservoir.

31
Dams, Reservoirs, and Canals
 Displacement of People
- Any villages present where the new
reservoir will fill in must be evacuated.
- The Three Gorges Dams in China will
force relocation of over a million people.
 Evaporation, Leakage, Siltation

- Evaporative losses from Lake Mead and
Lake Powell on the Colorado River is
about 1km3 per year (264 billion gallons).
- Dams slow water flow, allowing silt
(nutrients) to drop out.
32
Dams, Reservoirs, and Canals
• Loss of Free-Flowing Rivers
 Fish and other organisms will no longer be
able to travel freely up and down that part of
the river.

33
Evaporative losses from Lake Mead and Lake
Powell on the Colorado River is about 1km3
per year (264 billion gallons).
Domestic Conservation
• Estimates suggest many societies could
save as much as half of current domestic
water usage without great sacrifice or serious
change in lifestyle.
 What are the biggest domestic uses of
water?

35
WATER POLLUTION

• Any physical, biological, or chemical change
in water quality that adversely affects living
organisms can be considered pollution.
 Point Sources - Discharge pollution from

specific locations.
- Factories, power plants, oil wells

 Non-Point Sources - Scattered or diffuse,

having no specific location of discharge.
- Agricultural fields, feedlots, golf courses

37
Heavy Metal Pollutants
• Many metals such as mercury, lead,
cadmium, and nickel are highly toxic.
• They are highly persistent and tend
to bioaccumulate in food chains.
• Biggest sources:
 Mercury released from
incinerators and coal-burning
power plants.
 Mine drainage and leaching.

38
Other Inorganic Pollutants
• Nonmetallic Salts
 Biggest source is road salt
used during the winter.
 When the snow melts, the
salt runs off into nearby
rivers or lakes.
• Acids and Bases
 Changes the pH of the
water.
 Aquatic organisms are
very sensitive to pH
changes. 39
Organic Chemicals

• Organic compounds are complex molecules
that contain carbon.
• Two most important sources of toxic organic
chemicals in water are:
 Improper disposal of industrial and

household wastes.
 Runoff of pesticides from private lawns and

farms.

40
Organic Chemicals

• PCBs are one of the biggest and most
persistent examples of organic chemical
pollution
 Used for multiple electronic, wiring,

adhesive, and lubrication applications.
• PCBs are…
 Mutagenic

 Endocrine disruptors (mimic estrogen)

 Carcinogenic

41
This is a guide
to Lake
Michigan fish.

The fish with
the highest
level of
contamination
tend to be
larger or
bottom-
feeders.

42
Sediment Pollution

• Sediment is soil and rock particles that have
entered water due to erosion.
• Erosion is normal, but can be accelerated by
human activities.
• Sediment is beneficial (nourishes plants
found in floodplains) in small amounts but
can be harmful (smother aquatic life) when
there is too much.

43
Thermal Pollution

• Thermal pollution is dumping water into a
river, lake, or sea that is either much warmer
or much colder than normal.
 Oxygen levels in water decreases as

temperatures increase.

44
Groundwater Contamination

• Groundwater is highly susceptible to pollution
due to its location underground.
• Example sources:
- Leftover mining waste

- Radioactive waste

- Organic waste (manure)

- Unsealed municipal waste (landfills)

- Electricity generation waste (fossil fuels)

- Oil and gas drilling

45
Groundwater Pollution

46
Hydraulic Fracturing

• Hydraulic fracturing, or “fracking”, is a
controversial technique used to extract
natural gas from rock formations that are not
very permeable.
 Examples: Shale

and coal beds.

47
Natural Gas Deposits

• Fracturing has become an increasingly
popular tool for extracting natural gas,
especially with the discovery of the methane-
rich Marcellus Shale.

48
The Fracturing Process

• Fracturing fluid is pumped into a narrow hole
drilled into the rock formation.
• The pressure created from this fluid causes
the rock formation to crack.
• Sand is injected afterwards to fill the cracks,
because it is more permeable and allows the
methane to seep out.
 Most of the mixture injected into the rock

formation is rock and sand, however…

49
Fracturing Fluid

• A number of hazardous chemicals are also
present in the fracturing fluid.
 These include carcinogens and endocrine

disruptors.
 In a study published in 2010, the EPA

discovered contaminants in groundwater.
 The gas industry claims that it is

impossible for these fluids to enter
groundwater.

50
2005 Energy Policy Act

• The EPA has been unable to investigate
contamination due to fracturing for two
reasons:
1. The 2005 Energy Policy Act provides the

industry exemption from the Clean Water
and Drinking Water Acts.
2. The specific chemicals used in fracturing

are protected under copyright law as
trade secrets.

51
Incidents Resulting from Fracturing

• Methane gas has entered drinking water
supplies in Dimock, PA.
 Caused a water well explosion.

• A well explosion in Clearfield, PA sent
35,000 gallons of fracturing fluid into the
surrounding forests.
• Another well in Leroy, PA experienced a leak
and entered the groundwater.

52
Impaired Waters

• Impaired waters are rivers, lakes, and
estuaries that cannot fully support their
aquatic biological communities.
• Top three causes:
 Excess sediment

 Nutrients (nitrogen and phosphorous)

 Pathogenic microorganisms

53
Water Quality Today

Source: US EPA
http://pubs.usgs.gov/fs/FS-130-01/ 54
Water Testing Standards

• The EPA requires that local water treatment
plants provide yearly reports to residents
listing any contaminants found in the drinking
water supply.
• Must be tested for microbes several times a
day.
 Bottled water has much less strict

requirements.

55
Tap Water Quality

56
Source: Environmental Working Group; www.ewg.org
Local Tap Water Contaminants

• Chlorine treatment byproducts –
Bromodichloromethane,Dibromochloromethane,
haloacetic acids, bromoform, chloroform
 Formed when chlorine reacts with organic
matter found in water.
 Legal limit for these pollutants is 100 parts

per billion.
 LD50 of chloroform is about 900mg/kg.

57
Bottled Water?

• Spring water – From an underground source.
• Purified water – Treated with distillation,
ozonation, or reverse osmosis.
• Mineral water – Naturally contains certain
amounts of minerals from the source.
• Sparkling water – Naturally containing carbon
dioxide
• Artesian water – Source is a confined aquifer.
• Municipal water – Tap water.
58
Water Filtration

• Reverse Osmosis -
Pressurized water is sent
through a selective
membrane filter.
• Distillation – Water is boiled;
Steam is collected and
bottled.
• Ozonation – Ozone is
bubbled through water to kill
microorganisms.
59
Gold Mining

• Of all the metals that are mined, gold may be
the most polluting.
• Heap Leaching – A mining process that
extracts precious metals (such as gold) by
pouring a cyanide solution over the ore.
 The cyanide dissolves the gold or silver in

the crushed ore.
 The liquid is collected and the metals are

extracted from it.
 The cyanide is reused and the ore is

dumped. 60
Heap Leaching

61
Ocean Pollution

• In spring 2010, a beached whale died off the
coast of Seattle.
• Inside the whale’s stomach was found…
 A pair of sweatpants

 A golf ball

 20 plastic bags

 Surgeon’s gloves

 Duct tape

 Plastic pieces

• Did not play a role in whale’s death 62
Ocean Pollution

• The two biggest ocean pollutants:
 Oil

 Plastics

• Estimated 6 million metric tons of plastic
bottles, packaging material, and other litter
tossed from ships into the ocean annually.
 Plastic bottles gradually break down into

smaller pieces.
 They never fully decompose because they

are synthetic and not found in nature.
63
Ocean Pollution

64
Ocean Pollution

• Most of the oil in the ocean comes from
nonpoint sources.
• The biggest one is people dumping used
motor oil from their cars into the sink or storm
drains.
 Cause more long-term buildup.

• The biggest point source is oil spills or leaks
from oil platforms or tankers.
 The point sources are much more

concentrated and cause much more short-
term damage. 65
Oil Spills

• Exxon Valdez (1989) –
One of the worst incidents
of water pollution to ever
occur.
 High volume of oil

spilled
 Remote location and a

poor cleanup response
 Thousands of sea birds,

sea mammals, and fish
were killed. 66
Exxon Valdez and Tanker Design

• Resulted in the Oil Pollution Act of 1990
 Mandated a double-hull design for oil

supertankers by 2015.
 Would have reduced the oil spilled by

Exxon Valdez by 60%

67
Deep Water Horizon

• The Deepwater Horizon was a floating oil rig
in the Gulf of Mexico contracted to British
Petroleum.
• An explosion
occurred on
this rig in
April of 2010,
resulting in
the worst oil
spill ever.
68
Deep Water Horizon

• The rig was working
drilling and preparing
a well deep in the
seabed of the Gulf of
Mexico when a
sudden surge of oil
and natural gas
traveled up through
the rig, causing a
blowout at the
surface.
69
Deepwater Horizon

• Even as the
flames were
contained, the
oil continued
to gush out at
a rate of about
60,000 barrels
per day.

70
Deepwater Horizon

71
Aftermath

• Damage from the oil spill was the most
intense in three areas:
 The beaches of the nearby states,

especially Louisiana, Missisippi, and
Alabama.
 Underwater; Oil plumes stretched as long

as 10 miles in some spots.
 The sea floor; Oil and residue 2-5 inches

thick has been recorded in some areas.

72
Laws and Lawsuits

• BP reported actual cleanup costs of $3.12
billion.
• The Oil Pollution Act of 1990 also limited the
BP’s liability for non-cleanup costs to $75
million unless gross negligence can be
proven.
• BP estimates that its total costs of cleanup,
recovery, litigation, and restitution will be
about $40 billion.

73
Infectious Agents

• Main source of waterborne pathogens is
untreated and improperly treated human
waste.
 Animal wastes from feedlots and fields is

also an important source of pathogens.
• In developed countries, sewage treatment
plants and pollution-control devices have
greatly reduced pathogens.
 Coliform bacteria - Intestinal bacteria.

- Escherichia coli (E. coli)
74
Oxygen-Demanding Wastes

• Water with an oxygen content > 6 ppm will
support desirable aquatic life.
 Water with < 2 ppm oxygen will support

mainly detritivores and decomposers.
• Oxygen is added to water by diffusion from
wind and waves, and by photosynthesis from
green plants, algae, and cyanobacteria.
 Oxygen is removed from water by

respiration and oxygen-consuming
processes.
75
Oxygen-Demanding Wastes Cont’d
• Biochemical Oxygen Demand - Amount of
dissolved oxygen consumed by aquatic
microorganisms.
 Dissolved Oxygen Content - Measure of
dissolved oxygen in the water.
• Effects of oxygen-demanding wastes on
rivers depend on volume, flow, and
temperature of river water.
 Oxygen Sag - Oxygen levels decline
downstream from a pollution source as
decomposers metabolize waste materials.
76
Oxygen Sag

77
Plant Nutrients and Cultural Eutrophication

• Oligotrophic - Bodies of water that have clear
water and low biological productivity.
• Eutrophic - Bodies of water that are rich in
organisms and organic material.
 Eutrophication - Process of increasing

nutrient levels and biological productivity.
- Cultural Eutrophication - Increase in

biological productivity and ecosystem
succession caused by human activities.

78
79
80
WATER LEGISLATION

• Clean Water Act
 Enacted in 1972, amended in 1977 and

1987.
 Covers only “relatively permanent” waters,

including streams, oceans, rivers, and
lakes.
 Point-source pollutants cannot be

discharged into waters without permits
from their state.
 Does not address non-point pollutants.
81
POLLUTION CONTROL

• Source Reduction
 Cheapest and most effective way to deal

with pollution is avoid producing it or
releasing it into the environment.