ch5: water pollution

Question 1

Define water pollution:

Answer 1

• Any physical or chemical change in water that adversely affects the health of humans and other organisms
  
  • Varies in magnitude by location

Question 2

Types of water pollution:

Answer 2

• Sewage
• Disease-causing agents
• Sediment pollution
• Inorganic plant and algal nutrients
• Organic compounds
• Inorganic chemicals
• Radioactive substances
• Thermal pollution

Question 3

Sources of water pollution:

Answer 3

• Point sources
• Non-point sources

Question 4

Global water pollution issue:

Answer 4

• Lack of disease free water

Question 5

Define sewage:

Answer 5

• The release of wastewater from drains or sewers
• Include
  
  • Human wastes
  • Soaps
  • Detergents

Question 6

Sewage causes environmental problems which are:

Answer 6

• Enrichment
  
  • Fertilization of a body of water by high levels of plant and algal nutrients
    
    • Nitrogen and phosphorus
• Increase in BOD
  
  • Amount of oxygen needed by microorganisms to decompose biological wastes
    
    • As BOD increase DO decreases

Question 7

Sewage eutrophication:

Answer 7

• Oligotrophic
  
  • Unenriched, clear water that supports small populations of aquatic organisms
  • Causes:
    
    • Low nutrient levels
    • Good light penetration
    • High dissolved oxygen
    • Deep waters
    • Low algal growth
    • Small mouth bass, lake trout, pike, sturgeon, white fish
• Eutrophic
  
  • Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus
  • Often due to fertilizer or sewage runoff
  • Causes:
    
    • High nutrient levels
    • Poor light penetration
    • Low dissolved oxygen
    • Shallow waters
    • High algal growth
    • Carp, bullhead, catfish

Question 8

Define disease causing agents:

Answer 8

• Infectious organisms that cause diseases
  
  • Originate in the wastes of infected individuals
  • Common bacterial or viral diseases:
    
    • Typhoid
    • Cholera
    • Bacterial dysentery
    • Polio
    • Infectious hepatitis

Question 9

How is the presence of disease causing agents tested in the water?

Answer 9

• By fecal coliform tests
  
  • Testing for presence of E. coli in the water
    
    • The test indicate the presence of pathogenic organisms

Question 10

Sediment pollution:

Answer 10

• Excessive amounts of suspended soil particles
• Originates from:
  
  • erosion of agricultural lands,
  • forest soils exposed by logging,
  • degraded stream banks,
  • overgrazed rangelands,
  • strip mines, and
  • construction
• problems:
  
  • limits light penetration
  • covers aquatic animals and plants
  • brings insoluble toxins into water ways

Question 11

Compare streams with low vs high level of sediment

Answer 11

Stream with low level of sediment

Stream with high level of sediment

Many potential shelters for small aquatic organisms

Potential shelters buried under sediment

Light penetration supports photosynthesis of algae and aquatic plants

Sediment prevent light penetration; photosynthetic organisms cannot survive along bottom

Bacteria, protozoa, insect larvae attach to rocks

Aquatic organisms attached to rocks removed by sediment washing along bottom

Question 12

Inorganic plant and algal nutrients:

Answer 12

• Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae
  
  • Harmful in large concentrations
• Sources:
  
  • Human and animal wastes,
  • plant residues,
  • atmospheric deposition, and
  • fertilizer runoff
• Causes:
  
  • Enrichment,
  • bad odors, and
  • a high BOD

Question 13

Define dead zone:

Answer 13

• hypoxic (low-oxygen) areas in the world’s oceans and large lakes
• caused by:
  
  • Excessive nutrient pollution from human activities
• Effect:
  
  • Coupled with other factors it deplete the oxygen required to support most marine life in bottom and near-bottom water.

Question 14

Organic compounds:

Answer 14

• Chemicals that contain carbon atoms
• Natural examples:
  
  • sugars,
  • amino acids, and
  • oils
• Human-made examples:
  
  • pesticides,
  • solvents,
  • industrial chemicals, and
  • plastics

Question 15

inorganic chemicals:

Answer 15

• Contaminants that contain elements other than carbon
• Do not degrade easily
• Examples:
  
  • Acids
  • Salts
  • Heavy metals
  • Lead
    
    • Found in
      
      • old paint
      • industrial pollutants
      • lead gasoline
  • mercury
    
    • mercury bio accumulates in the muscles of top predators of the open ocean

Question 16

Radioactive substances:

Answer 16

• Contain atoms of unstable isotopes that spontaneously emit radiation
• Sources:
  
  • Mining
  • Processing radioactive materials
  • Nuclear power plants
  • Natural sources

Question 17

Thermal pollution:

Answer 17

• Occurs when heated water produced during industrial processes is released into waterways
• Organisms affected
  
  • Temperature affects:
    
    • reproductive cycles,
    • digestion rates, and
    • respiration rates
  • Warm water holds less DO than cold water

Question 18

How do we measure water quality?

Answer 18

• Dissolved Oxygen:
  
  • BOD Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposers
• Chemical Analysis:
  
  • looking for presence of inorganic or organic chemicals
• Suspended Sediment
  
  • water clarity

Question 19

Point source pollution:

Answer 19

• water pollution that can be traced to a specific origin
• Discharge via
  
  • pipes,
  • sewage, and
  • ditches

Question 20

Non-point source pollution:

Answer 20

• Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry
• Diffuse, but its cumulative effect is very large
• Ex: runoff from agricultural fields or parking lots

Question 21

Water Pollution from Agriculture

Answer 21

• Agriculture is leading source of water pollution in US
  
  • Animal wastes and plants residues have high BOD
  • Chemical pesticides can leach into groundwater
• Almost all streams and rivers are polluted with agricultural pesticides

Question 22

Industrial Wastes in Water

Answer 22

• Different industries generate different pollutants
  
  • Food processing plants- high BOD
  • Paper mills- High BOD and toxic compounds
• Many industries recover toxins before they go into the waste stream

Question 23

Ocean Pollution:

Answer 23

• Oceans can disperse and break down large quantities of degradable pollution if they are not overloaded.
  
  • Pollution worst near heavily populated coastal zones
  • Wetlands, estuaries, coral reefs, mangrove swamps
  • 40% of world’s pop. Live within 62 miles of coast

Question 24

Ocean pollution contain:

Answer 24

• Large amounts of untreated raw sewage (viruses)
• Leaking septic tanks
• Runoff
• Algae blooms from nutrients
• Dead zones NO DO
• Airborne toxins
• Oil spills

Question 25

Improving Water Quality-Purification of Drinking Water

Answer 25

• Municipal water supplies are treated
• Collected from water or reservoir
• Treated