BI 105A Environmental Biology

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BI 105AEnvironmental Biology

• Professor Jill Nissen
• Montgomery College
• Fall 2006

2
Water Pollution

• Chapter 22

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Water Pollution

• Any physical or chemical change in water that
  negatively impacts the health of humans or any
  other organism.

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Categories Of Water Pollution

• Sewage
• Disease causing agents
• Sediment pollution
• Inorganic plant and algal nutrients
• Organic compounds
• Inorganic chemicals
• Radioactive substances
• Thermal pollution
• Mini-glossary, p. 488

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Some Types of Water Pollution

• Disease Causing Agents
• Infectious agents such as viruses and bacteria.
• Spread diseases such as typhoid, cholera,
  dysentery, and hepatitis.
• Originate from waste of infected individuals.
• Inorganic Plant Algal Nutrients
• Chemicals such as phosphorus and nitrogen.
• Stimulate excessive growth of plants and algae,
  causing enrichment, bad odors, and high BOD.
• Originate from animal waste, plant residues, and
  fertilizer runoff.
• Inorganic Chemicals
• Acids, salts, and heavy metals such as lead and
  mercury.
• Associated with a variety of health problems
  specific to each contaminant.
• Originate from industries, mines, drilling, and
  urban runoff.

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3 Common Contaminants of the Chesapeake Bay

• Bacteria Sewage systems are one significant
  source.
• Nutrients Nitrogen and phosphorus from
  fertilizers.
• Toxic Substances Industries, agriculture,
  household chemicals and pesticides.

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Fish Advisories

• In many areas of the Bay, some fish have enough
  pollutants in their tissue that consumption
  should be limited or avoided
• http//www.mde.state.md.us/CitizensInfoCenter/Fish
  andShellfish/home/index.asp

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Biochemical oxygen demand (BOD)

• Biochemical oxygen demand (BOD) is the amount of
  oxygen required by microorganisms to decompose
  the organic substances in sewage. More sewage
  means higher BOD.

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Anoxia

• Dissolved Oxygen (DO) is the amount of oxygen
  present in the water, measured in milligrams per
  liter (mg/l).
• Healthy Water 5.0 mg/l or more of dissolved
  oxygen.
• Hypoxia low levels of dissolved oxygen (2.0
  5.0 mg/l).
• Severe Hypoxia very low levels of dissolved
  oxygen (0.2 2.0 mg/l).
• Anoxia very little or no oxygen (0 0.2 mg/l).

During the past two decades, summer-long anoxia
has occurred almost yearly in the Chesapeake Bay
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The Dead Zone

• Just like humans, most living creatures in the
  Chesapeake Bay need oxygen to survive.
• When the dissolved oxygen levels drop too low,
  many aquatic species die.
• The Chesapeake Bays dead zone, stretches for
  hundreds of square miles during the summer. 

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Eutrophic

• A body of water that is extremely rich in
  nutrients and is characterized with high
  biological productivity biomass

• Characteristics of a eutrophic lake
• Cloudy water.
• Poor light penetration.
• Often Shallow.
• Oxygen deficient.
• Can be accelerated by human activity.
• Contains large populations of aquatic animals.

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Oligotrophic

• Lakes, estuaries, and slow flowing streams that
  have minimal levels of nutrients and lowest
  levels of biological productivity.

• Characteristics of an oligotrophic lake
• Clear water.
• Rich with Oxygen.
• Low in Nitrogen.
• Nutrients are short in supply.
• Supports small populations of aquatic organisms.
• Less plant debris accumulated on the bottom over
  the years.

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Point Nonpoint Source Pollution

• Point Source Pollution is pollution that can be
  traced to a specific site
• Oil spill
• Thermal pollution from a power plant
• Discharge from a sewage treatment plant
• Nonpoint Source Pollution is pollution that
  enters a body of water over large areas rather
  than at a single point
• Agricultural runoff
• Mining wastes
• Sediments from construction
• Urban runoff

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Major Sources ofWater Pollution

• Agricultural Organic or inorganic pollutants in
  surface waters groundwater (such as animal
  waste or sediment from eroded cropland).
• Municipal Waste water from homes and commercial
  establishments (including urban runoff combined
  sewer system overflow).
• Industrial Pollutants in waste water from
  different industries (such as toxic compounds and
  sludge from paper mills).

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Safe Drinking Water Act, 1974

• Established to have uniform federal standards to
  protect drinking water.
• Requires the EPA to establish the maximum
  contaminant level, review risks in drinking
  water, and revise the drinking water standards.
• The 1996 amendment requires water suppliers to
  tell consumers what contaminants are present in
  their water system.

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Clean Water Act, 1977

• Established to eliminate discharge in waterways
  and achieve water quality safe for fishing,
  swimming, etc.
• Requires the EPA to set and monitor national
  emission limitations.
• Polluters must obtain permits or be fined.
• The 1987 amendment expanded the system to include
  nonpoint sources, but they are more difficult and
  expensive to regulate.

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How you can help

• Dispose of household chemicals, medicines, and
  motor oil properly.
• Pick up pet wastes, litter, leaves, and debris to
  keep them out of street gutters and storm drains.
• Apply lawn and garden chemicals sparingly.
• Drive less and make sure your car is
  well-maintained.
• Wash your car on a porous surface such as your
  lawn.

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Review Objectives

• Types of Water Pollution Define water
  pollution. List and briefly define eight
  categories of water pollutants. Discuss how
  sewage is related to eutrophication, biochemical
  oxygen demand (BOD), and dissolved oxygen.
  Describe water quality issues in the Chesapeake
  Bay. Distinguish between oligotrophic and
  eutrophic lakes.
• Water Quality Today Contrast point source
  pollution and nonpoint source pollution.
• Laws Controlling Water Pollution Compare the
  goals of the Safe Drinking Water Act and the
  Clean Water Act.