National Center for Case Study Teaching in Science
Erosion of Soil
Pollution of Air and Water
A Supplement to A Tale of Twin Towns: Natural Capital Degradation
by
Vandana A. Gudi
Department of Science
Robert Morgan Educational Center, Miami, FL
Natural Capital Degradation
By
1. Deforestation (Logging)
2. Mining
3. Burning of Fossil fuel
4. Acid rain
5. Agriculture & Industrialization
6. Eutrophication
7. Human ignorance
2
Deforestation
3
Deforestation: Harmful to the Environment
• Causes soil erosion
• Results in decreased soil fertility
• Eroded soil runoff may increase turbidity in
the nearby water reservoirs
• Extensive clearing of forests may change local
climate
• Flooding becomes common as there is no soil
to retain water
4
Logging
Advantages
• Renewable resource
• Jobs
Disadvantages
• Damages surrounding ecosystems
• Decreases biodiversity
• Decreases recreational opportunities
5
Mining: Nonrenewable (Mineral) Resources
Extraction and processing of minerals causes …
•
•
•
•
Habitat destruction
Soil erosion
Air & water pollution
Solid waste
generation
6
Acid Mine Drainage
7
Acid Drainage
8
Air Pollution
Acid Rain due to Fossil Fuel Consumption
(Regional Problem)
Sources:
• Coal burning power plants
• Ore smelters
• Industrial plants
Harmful effects:
• Causes respiratory diseases
• Metal corrosion &
weathering of stone
sculptures
• Haze
• Harmful to aquatic life
Pollutants:
• Sulfur dioxide, Nitrogen
oxides, suspended
particulates
• Primary pollutants become
secondary pollutants such as
HNO3, H2SO4, during
transportation over several
kilometers by prevailing
winds
• Dry deposition of
particulates as SO4 & NO3
salts, away from the source 9
Acid Rain Formation
10
Effects of Acid Rain
Usually mountain top ecosystems with thin soil cover and
low amounts of Ca and Mg salts (low buffering capacity)
in the soil are vulnerable to acid rain damage
11
Acid Rain on Forests
•
•
•
•
Acid rain when pH of rain is < 5.1
Acids leach Ca & Mg salts from soils
Soils lose their buffering capacity
Ca-deficiencies in plants growing in such soils can
pass to primary consumers. Ex. Birds lay eggs with
brittle shells
12
Effects of Acid Rain cont.
• Low pH releases highly toxic ions such as Al, Hg, Pb,
and Cd from insoluble compounds in soil. Absorption
of these ions makes trees weak.
• Weak trees become vulnerable to low temperatures,
drought, and to infection by insects and acid loving
mosses.
13
Types of Sources of Water Pollution
• Point Sources are easy
to locate and control
• Discharge at specific
locations
• Ex. drain pipes, sewer
lines
• Culprits: industries,
sewage treatment plants
• Non-Point Sources are
dispersed and difficult
to pin point
• Ex. agricultural run off,
run off from live stock
feed lots, lawns of
suburban
neighborhoods,
construction sites,
streets and parking lots,
acid rain etc.
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Major Sources of Water Pollution
• Agriculture: agricultural runoff, erosion from
overgrazed land, microorganisms from live
stock, wastes from food processing industries,
excess salts from soils of irrigated crop land
• Industries: wastes stored can leach to surface
and/or ground water
• Surface mining: disturbs earth’s surface, runoff
of toxic chemicals
15
Pollution of Fresh Water Streams
• As the water is flowing, moderate amounts of
biodegradable wastes and excess heat gets diluted
easily in a stream
• It is a problem when large amounts of pollutants
contaminate the stream or
• The water flow is reduced due to
a. Drought,
b. Damming or
c. Diverted to agriculture or industries
16
Pollution of Fresh Water Reservoirs
• Surface water reservoirs like lakes can easily get
contaminated with pollutants as water is mostly
stagnant
• Additionally, there is little vertical mixing among the
stratified layers of a lake which further inhibits the
dilution of the pollutant
• Air pollutants produced by industries and
automobiles, agricultural run off, run off from mining
and construction sites, run off from streets and lawns
are the major sources leading to nutrient overload of
lakes
17
Runoff
Runoff from farm fields reaches sediment-laden stream
in southwestern Iowa
Construction site runoff in Davidson, North Carolina
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Eutrophication
1. Nutrient rich runoff
from farmlands to
surface water reservoirs
allows phytoplanktons
to grow uncontrollably.
So zooplanktons that
feed on them grow
uncontrollably too.
2. When phytoplanktons &
zooplanktons die and
sink to the bottom,
aerobic decomposers
metabolize them,
consuming almost all of
the dissolved O2 in the
water creating a
hypoxic zone where no
aerobic organisms can
live.
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20
Relationship between Dissolved
Oxygen Levels and Water Quality
DO (ppm) at 200C
8.0-9.0
6.7-8.0
4.5-6.7
Below 4.5
Below 4.0
Water Quality
Good
Slightly Polluted
Moderately Polluted
Heavily Polluted
Gravely Polluted
Miller T. G. 2005. Living in the Environment, 14th edition, Brooks/Cole, Page 492.
21
How Ground Water Gets Polluted?
• Leakage from underground septic tanks, industrial
waste storage tanks, chemical storage ponds,
agricultural runoff can easily contaminate water in an
aquifer
• The plume of contaminated water may reach a well
which is used as a source of ground water for human
consumption and/or for agriculture
22
Contaminated Ground Water is a
Serious Problem
• Unlike surface water, ground water does not get
diluted of pollutants as it flows extremely slowly
• The decomposers responsible to degrade
contaminating organic matter are low in number due
to the lower amounts of dissolved oxygen in ground
water
• The colder temperatures of aquifers further slow
down the rate of decomposition
23
Ground Water Contamination is Permanent
on a Human Time Scale
• Ground water contaminated with biodegradable
wastes cleanses itself within hundreds to thousands of
years
• Ground water contaminated with non degradable
wastes such as lead, arsenic, fluoride stays like that
permanently
24
Sources of Ground Water Pollution
25
Is the Water Safe to Drink?
• As per World Health Organization, about one in every
seven people does not have access to clean drinking
water
• About 1.6 million people die prematurely every year
due to contaminated water or unhygienic conditions
due to lack of water
http://www.who.int/water_sanitation_health/mdg1/en/
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Pollutants in Drinking Water are
Harmful to Human Health
• High levels of naturally occurring fluoride(F-) in drinking
water may lead to crippling backbone disease, neck damage
and is responsible for many dental problems
• NO3 ions from agricultural run off can contaminate ground
water. NO2 ions in the digestive system react with these NO3
ions in the water after human consumption to form organic
intermediates which can be carcinogenic
• These NO3 ions when in blood interfere with oxygen
circulation especially in infants causing ‘blue baby syndrome’
• Arsenic(As) enters drinking water when a well is drilled in the
rock naturally rich in it. Long term exposure to As may lead to
various cancers
27
Solutions to Groundwater Pollution
Prevention is better…
1.
2.
3.
Solutions:
Limit the use of polluting
1. Bioremediation
chemicals in the
2. Pump up the polluted water
environment, find
to clean up, then return to
alternates
aquifer (may not be cost
Quick detection system for
efficient)
leakage of underground
3. Prevention is better than
storage tanks and pipe
cure!
lines
No dumping of hazardous
wastes in landfill, make
people aware of recycling
centers
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How to Keep Ground Water Safe?
• Reduce the use of chemical fertilizers by planting native trees
• Increase use of greywater (treated waste water from homes
and office buildings)
• Use ecologically friendly methods to treat sewage (black
water)
• Minimize industrial air pollution
• Educate public about refuse, reduce, reuse and recycle
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How to prevent water pollution?
Water pollution can be prevented by educating the
public on the following issues:
• Why the use of synthetic, chemical fertilizers, and pesticides
should be reduced and the use of green fertilizer or manure
should be increased
• How to compost the kitchen organic waste
• Never to dump household chemicals such as oil (frying oil or
car oil), paint thinners, paints, pesticides, unwanted medicines
etc. onto the ground or down the drain
• Never to apply pesticides or synthetic fertilizers near a water
reservoir
• How to grow your own vegetables or encourage public to buy
organic food to support organic food industry
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Reference
Miller T. G. 2005. Living in the Environment, 14th edition. Brooks/Cole.
•
•
•
•
•
Chapter 11. Sustaining Terrestrial Biodiversity: Managing and Protecting Ecosystems. Human impact on ecosystems,
managing and sustaining forests, tree harvests, deforestation, logging in U.S. National Forests, etc. Pages 194-223
Chapter 15. Water Resources. Supply, renewal and use of various water resources, withdrawing ground water, depletion of
ground water, reducing wastage of purified water, etc. Pages 305-330
Chapter 16. Geology and Nonrenewable Mineral Resources. Surface and subsurface mining, different types of surface
mining, environmental impact of surface mining etc. Pages 331-349
Chapter 20. Air Pollution. Primary and secondary pollutants, local and regional effects of air pollution, acid deposition,
effects of acid deposition, etc. Pages 433-460
Chapter 22: Water Pollution. Sources of water pollution, point and nonpoint sources, pollution of streams, lakes and ground
water, solution, etc. Pages 491-517
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Image Credits
Slide 3
Description: Deforestation in the Usambara Mountains in Lushoto District, Tanga Region, Tanzania.
Author: Mohsin Karmali
Link: http://commons.wikimedia.org/wiki/File:Lushoto.jpg
Clearance: CC BY 2.5
Slide 5
Description: Logging; “Zrywka drewna 776”
Author: Przykuta
Link: http://commons.wikimedia.org/wiki/File:Zrywka_drewna_776.jpg#mediaviewer/File:Zrywka_drewna_776.jpg
Clearance: CC BY-SA 3.0
Slide 6
Description: Mining; “Schaufelradbagger (Vorraumbagger) im Tagebau Welzo”
Author: JaySef
Link: http://commons.wikimedia.org/wiki/File:Schaufelradbagger_Welzow_1404.jpg
Clearance: CC BY-SA 3.0
Slide 7
Description: Diagram of acid mine drainage at Iron Mountain Mine
Author: Believed to be U.S. Geological Survey, Department of the Interior/USGS, U.S. Geological Survey.
Link: http://ca.water.usgs.gov/projects/iron_mountain/environment.html
Clearance: http://www.usgs.gov/laws/info_policies.html
Slide 8
Description: Acid mine drainage causes severe environmental problems in the Rio Tinto, Spain.
Author: Carol Stoker, NASA
Link: http://commons.wikimedia.org/wiki/File:Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center.jpg
Clearance: This file is in the public domain because it was solely created by NASA. NASA copyright policy states that
“NASA material is not protected by copyright unless noted.”
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Image Credits cont.
Slide 10
Description: Acid rain formation diagram.
Author: Unspecified, EPA
Link: https://blog.epa.gov/acidrain/2010/04/what-is-acid-rain/
Clearance: United States Environmental Protection Agency
Slide 11
Description: Photo showing the effects of acid rain, woods, Jizera Mountains, Czech Republic.
Author: Nipik
Link: http://commons.wikimedia.org/wiki/File:Acid_rain_woods1.JPG
Clearance: Released to the public domain by the author.
Slide 18 (left)
Description: Photo of agriculture runoff.
Author: Photo by Lynn Betts, USDA Natural Resources Conservation Service.
Link: http://commons.wikimedia.org/wiki/File:NRCSIA99139_-_Iowa_%282979%29%28NRCS_Photo_Gallery%29.jpg
Clearance: This image is a work of the Natural Resources Conservation Service, part of the United States Department of
Agriculture, taken or made as part of an employee's official duties, and accordingly in the public domain.
Slide 18 (right)
Description: Photo of construction site runoff.
Author: Brett VA
Link: http://commons.wikimedia.org/wiki/File:Construction_runoff_Davidson_%286124078615%29.jpg
Clearance: CC BY-SA 3.0
Slide 20
Description: Photo of Lake Maracaibo, Venezuela, contaminated by Lemna minor (duckweed) due to nutrient pollution.
Author: “The Photographer”
Link: http://commons.wikimedia.org/wiki/File:Aguas_del_lago_de_Maracaibo_contaminadas_por_Lemna_03.JPG
Clearance: Released to the public domain by the author.
Slide 25
Description: Diagram showing sources of ground water pollution.
Author: Chris Wardle of the British Geological Survey.
Link: http://www.groundwateruk.org/Image-Gallery.aspx
Clearance: Diagram courtesy of the UK Groundwater Forum; “permission is freely granted for …use in academic and noncommercial publications “ (http://www.groundwateruk.org/Image-Gallery.aspx).
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