16.8.2: Chapter Questions

Study Question

1. What is the difference between contamination and pollution?
2. Explain assimilative capacity. How are assimilative capacity and residence time linked?
3. How can human activities alter primary production?
4. Which human activities cause alterations in marine habitats? How many can you list? In what way do each of these activities alter habitat?
5. How can we evaluate the toxicity of a substance to marine species? Why is it so difficult to decide what concentration is safe in the environment?
6. What is the difference between bioaccumulation and biomagnification? Why should we be more concerned about toxic substances that are biomagnified?
7. In what ways can fishing damage the marine ecosystem?
8. List the principal sources of contamination in the oceans. Summarize the characteristics of each type of waste or other source
9. What are antifouling paints? What would be the desirable characteristics of a future antifouling paint?

Critical Thinking Questions

1. What is the difference between naturally occurring toxic substances and synthetic toxic substances that suggests that they might be considered differently by policy makers and managers concerned with marine pollution?
   (a) Do you think discharges of these two types of substances should be subject to different rules? Why or why not?
   (b) Do you think the production of all synthetic toxic substances (without any exception) should be banned?
   (c) If only some such substances are to be banned from being produced while others are allowed to be produced but their discharges regulated, what factors would you consider in deciding which of these two policies should be applied to a specific synthetic toxic substance?
2. In this chapter, it is speculated that the use of oceans for sewage waste disposal was one of the most effective advancements in human health protection in history. Do you think this statement is correct? Why or why not?
3. DDT has been banned from production and use in many countries, primarily in mid-latitudes, where it was previously used on crops for insect control. However, DDT is still produced and used in large amounts in some nations, particularly developing nations in tropical regions where malaria is rampant. Although effective substitutes for DDT exist, they are not used in these countries, because they cost too much. What should be done about this situation, and how?
4. On an annual average, petroleum hydrocarbons from street runoff contribute more than twice the volume of oil spilled in the oceans from tanker accidents.
   (a) What are the sources of petroleum hydrocarbons in street runoff?
   (b) What would you suggest politicians do to reduce the amount of petroleum hydrocarbons released to bays and estuaries by this route?
   (c) Should politicians require all storm water runoff to be treated to remove the hydrocarbons?
   (d) Should politicians attempt to control the release of hydrocarbons to the environment so that they do not get into the storm water? How could this be done?
   (e) What can you personally do to reduce the amount of hydrocarbons that you release to the environment?
5. Describe the principal sources of petroleum contamination in the oceans. Discuss what would probably cause more pollution of the oceans: production of oil from drilling platforms in U.S. coastal waters and transport of the oil ashore in seafloor pipelines, or purchase of oil from foreign suppliers and transport to the United States in oil tankers.
6. Because of environmental concerns, offshore oil exploration is currently banned in large areas of the Pacific and Atlantic continental shelves of the United States, despite the successful safety record of the oil industry operating under U.S. laws and regulations. Some oil companies are drilling instead in other areas, such as the ice-filled waters near the Russian island of Sakhalin, where the safety and environmental rules are weaker and sometimes totally unenforced, and from where the oil must be transported long distances to the locations where it is used.
   (a) Discuss the implications that drilling operations like the one conducted off Sakhalin Island might have for the ocean environment as a whole.
   (b) Should the drilling bans in U.S. waters be continued? Describe all the reasons for your answer.
   (c) If the ultimate political decision were to increase the drilling and oil activity in U.S. waters, what studies should be done or actions taken before such drilling took place?
   (d) Have such studies been done already?
7. Describe the principal adverse effects of sewage discharged to the oceans and how they can be reduced or eliminated. What actions have been taken to reduce or eliminate sewage pollution of the oceans in the United States? Have these actions been effective?
8. Billions of dollars have been spent on the construction of secondary sewage treatment plants in all cities and towns regardless of the locations of their discharges.
   (a) Was this uniform approach justified scientifically? If so, why? If not, what other approaches to sewage treatment and disposal might have been taken?
   (b) What are the characteristics of sewage that you would wish to modify by alternative treatment approaches before discharging it to the oceans?
   (c) What are the factors that you would consider in deciding where you might not require secondary treatment or where you might allow only primary treatment?
   (d) How would you determine the environmental benefits or detriments of alternative treatments?
9. Numerous sources release trace metals, toxic organic substances, nutrients, and pathogenic microorganisms to the environment. These releases are eventually discharged to the oceans in sewage, urban storm-drain runoff, and runoff from agricultural land.
   (a) List as many of these sources as possible.
   (b) What substances do the various sources contain
10. After you have answered Critical Thinking Question 9 above, take a look at the labels on all of the containers of cleaning fluids and powders, cosmetics, shampoos, paints, and other materials around your house.
    (a) What additional sources can you now list?
    (b) Where do these products and their chemical constituents go after you have used them?
    (c) Make two lists: one of the products whose containers tell you enough about their composition for you to decide what contaminants they might release to the environment, and another of those that do not. Do you know what is in the products that do not tell you on their label what they contain?
    (d) Why do some products have information on their labels that divulge their composition, while other products do not? Should this situation be changed? If so, how?
11. Discuss why it is more difficult to control contamination of the oceans from urban and agricultural inputs than from industrial inputs.