Erosion of Soil Pollution of Air and Water

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  • Natural Capital Degradation
  • A Supplement to A Tale of Twin Towns: Natural Capital Degradation
  • by
  • Vandana A. Gudi Department of Science
  • Robert Morgan Educational Center, Miami, FL
  • National Center for Case Study Teaching in Science

Natural Capital Degradation

  • By
  • Deforestation (Logging)
  • Mining
  • Burning of Fossil fuel
  • Acid rain
  • Agriculture & Industrialization
  • Eutrophication
  • Human ignorance


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


  • Advantages
  • Renewable resource
  • Jobs

Mining: Nonrenewable (Mineral) Resources

  • Habitat destruction
  • Soil erosion
  • Air & water pollution
  • Solid waste generation
  • Extraction and processing of minerals causes …

Acid Mine Drainage

Acid Drainage

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
  • Acid Rain Formation

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

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

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.

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.

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

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
      • Drought,
      • Damming or
      • Diverted to agriculture or industries

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
  • Construction site runoff in Davidson, North Carolina
  • Runoff
  • Runoff from farm fields reaches sediment-laden stream in southwestern Iowa


  • 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.

Relationship between Dissolved Oxygen Levels and Water Quality

  • DO (ppm) at 200C
  • Water Quality
  • 8.0-9.0
  • Good
  • 6.7-8.0
  • Slightly Polluted
  • 4.5-6.7
  • Moderately Polluted
  • Below 4.5
  • Heavily Polluted
  • Below 4.0
  • Gravely Polluted
  • Miller T. G. 2005. Living in the Environment, 14th edition, Brooks/Cole, Page 492.

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

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

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

Sources of Ground Water Pollution

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

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

Solutions to Groundwater Pollution

  • Prevention is better…
  • Limit the use of polluting chemicals in the environment, find alternates
  • Quick detection system for leakage of underground storage tanks and pipe lines
  • No dumping of hazardous wastes in landfill, make people aware of recycling centers
  • Solutions:
  • Bioremediation
  • Pump up the polluted water to clean up, then return to aquifer (may not be cost efficient)
  • Prevention is better than cure!

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

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


  • 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

Image Credits

  • Slide 3
  • Description: Deforestation in the Usambara Mountains in Lushoto District, Tanga Region, Tanzania. Author: Mohsin Karmali Link: Clearance: CC BY 2.5
  • Slide 5
  • Description: Logging; “Zrywka drewna 776” Author: Przykuta Link: Clearance: CC BY-SA 3.0
  • Slide 6
  • Description: Mining; “Schaufelradbagger (Vorraumbagger) im Tagebau Welzo” Author: JaySef Link: 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: Clearance:
  • Slide 8
  • Description: Acid mine drainage causes severe environmental problems in the Rio Tinto, Spain. Author: Carol Stoker, NASA Link: 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.”

Image Credits cont.

  • Slide 10
  • Description: Acid rain formation diagram. Author: Unspecified, EPA Link: Clearance: United States Environmental Protection Agency
  • Slide 11
  • Description: Photo showing the effects of acid rain, woods, Jizera Mountains, Czech Republic. Author: Nipik Link: 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: 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: 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: 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: Clearance: Diagram courtesy of the UK Groundwater Forum; “permission is freely granted for …use in academic and non-commercial publications “ (

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