Chapter 18

Question 1

Define point source and non-point sources of pollution.

Answer 1

• Point Sources : Discharge pollution from specific locations: Factories, power plants, drain pipes.
• Nonpoint Sources : Having no specific location of discharge from farms , golf courses, residential construction sites, as well as from atmospheric deposition carried by air currents and precipitated into watersheds or directly onto surface waters as rain, snow, or dry particles.

Question 2

Provide examples for

Infection agents  
Thermal  
Inorganic chemicals  
Radioactive materials 
natural sources  
Sediment  
Plant nutrients  
Oxygen demanding wastes 
Organic chemicals

Answer 2

• Infection Agents: Bacteria, viruses, parasites
• Thermal: Heat
• Inorganic Chemicals: Acids(from coal mining and fossil fuel combustion), base, salts, metals( mercury, lead, cadmium, nickel)
• Radioactive Materials: Uranium, iodine, radon
• Natural Sources:
• Sediment: Soil, silt
• Plant Nutrients: Nitrates, phosphates, ammonium
• Oxygen Demanding Wastes: Animal manure, plant residues
• Organic Chemicals: Pesticides, plastics, detergents, oil, gasoline

Question 3

What is oxygen sag?

Answer 3

•Downstream from the polluted areas where pollution is high, biochemical oxygen demand increases, resulting in and oxygen content drop in water(oxygen sag).

Question 4

What ppm oxygen levels will support desirable aquatic life?

Answer 4

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

Question 5

Define BOD and DOC and what are the differences between the two?

Answer 5

• -Biochemical Oxygen Demand(BOD): amount of dissolved oxygen consumed by aquatic microorganisms. Used as a test for organic waste contamination from sewage, paper pulp, and food waste.
• Dissolved Oxygen Content (DOC)- measure of dissolved oxygen in the water. Effects of oxygen-demanding wastes on rivers depend on volume, flow, and temperature of river water.

Question 6

Define:

Cultural Eutrophication,
Eutrophic,
Eutrophication,
Oligotrophic

Answer 6

• Cultural Eutrophication: increase in biological productivity caused by human activities. Algal “blooms” often result and the decomposition of the algae depletes oxygen in the water.
• Eutrophic: Bodies of water that are rich in organisms and organic material.
• Eutrophication: process of increasing nutrient levels and biological productivity, a normal part of successional change in most lakes
• Oligotrophic: bodies of water that have clear water and low biological productivity.

Question 7

What problem will algal bloom cause in water?

Answer 7

•Algal “blooms” often result and the decomposition of the algae depletes oxygen in the water.

Question 8

What is the cause of Red Tide?

Answer 8

•Red tides: due to dinoflagellate blooms : Have become increasingly common in slow-moving and shallow waters. Dinoflagellates are single-celled organisms found in marine zones that are polluted due to eutrophication. Dinoflagellates release toxins poisoning the fish.

Question 9

Per Municipal Sewage Treatment: what are the functions of primary, secondary and tertiary treatments?

Answer 9

• 1-Primary Treatment - physical separation of large solids from the waste stream
• 2-Secondary Treatment - biological degradation of dissolved organic compounds. Effluent from primary treatment transferred into trickling bed, or aeration tank. Effluent from secondary treatment is usually disinfected (chlorinated) before release into nearby waterway.
• 3-Tertiary Treatment - removal of plant nutrients (nitrates and phosphates) from secondary effluent. Chemicals which bind or natural wetlands. In many U.S. cities, sanitary sewers are connected to storm sewers. Heavy storms can overload the system, causing by-pass dumping of raw sewage and toxic runoff directly into surface water.

Question 10

What is the purpose of Water Pollution Control Act(1972)

Answer 10

• Established a National Pollution Discharge System which requires a permit for any entity dumping wastes in surface waters and requires disclosure of what is being dumped.

Question 11

What is the purpose of Clean Water Act of 1985(Amending the 1972 Water Pollution Control Act).

Answer 11

• Goal was to return all U.S. surface waters to “fishable and swimmable” conditions. Agricultural runoff and urban nonpoint pollution is the largest source of surface water degradation, but regulation remains a problem.

Question 12

What CRECLA stands for and what is its purpose?

Answer 12

• Compensation, Environmental Response, Compensation, and Liability Act(CERCLA): of 1980 created Superfund program to clean up toxic waste sites