Online Sample - Chapter 1 Environmental Interrelationships

Environmental Science: A Study of Interrelationships, 6th/ed., 6th/ed.

Chapter 1 Sample

Chapter 1 Environmental Interrelationships

1-A TRUE-FALSE QUESTIONS

Where "F" is your answer, change the underlined portion (and the underlined portion only) of the statement to make it true.

___1. The official name of the 1992 Rio de Janeiro Earth Summit is the World Conference on the Environment.

___2. An ecosystem is a dynamic complex of plants, animals, microorganisms and their physical environment interacting and functioning as an essentially self-sustaining unit.

___3. Soil erosion leads to siltation of rivers, which in turn may lead to fish kill.

___4. The use of pesticides in agriculture often results in both surface water and groundwater pollution.

___5. Natural ecosystems do not require material input or energy input to sustain themselves.

___6. In an ecosystem, a living organism interacts with other organisms but not with the physical components of the environment.

___7. Through bioaccumulation, toxic chemicals that are very dilute in the environment can reach dangerously high concentrations in the fatty tissues and organs of fish, mammals and birds.

___8. The excessive growth of algae in rivers and lakes is often due to inputs of calcium and carbon from farmland runoff and sewage treatment plant outfall.

___9. A smokestack is an example of a point source of pollution.

___10. The loss of old-growth forests is one of the major environmental concerns in the Dry West of Canada.

1-B MATCHING QUESTIONS

Match each of Q.1-7 with the most appropriate item from the following list. Any item in the list may be used more than once, or not at all.

a. Wilderness North b. Agricultural Middle c. Dry West d. Forested West e. Great Lakes and Industrial NE f. Diverse South g. edge effect

___1. Long-term use of irrigated lands in this region often results in the buildup of salts in the soil.

___2. This region has the most fragile and vulnerable ecosystems of all.

___3. Old-growth forests are being logged here.

___4. Soil erosion and groundwater pollution are common in this region.

___5. It develops when a large forest is carved up and divided into smaller patches.

___6. Loss of wetlands and salt water intrusion are causes for concern in this region.

___7. Industry in this region is the main source of acid deposition and toxic wastes in the environment.

1-C MULTIPLE-CHOICE QUESTIONS

___1. Environmental problems are difficult to resolve mainly because a. the problems are technically too complex. b. they are interrelated with societal issues like jobs and growth. c. the required anti-pollution equipment is not commercially available. d. industries continue to pollute.

___2. In an ecosystem, all components each other. a. help b. compete with c. act independently of d. interact with

___3. Which of the following statements about the IJC is false? a. It was established in 1909. b. It remains to be a major scientific organization today. c. It plays a major role in Great Lakes water quality issues. d. Its full name is Interprovincial Joint Commission.

___4. From the ecological point of view, old-growth forests ought to be preserved mainly because these forests a. contain trees that are old and special. b. support rare species of birds. c. serve as the habitats for unique, diverse communities. d. provide us with more oxygen and help reduce the greenhouse effect.

___5. If PCB concentrations in phytoplankton in a lake are in the neighborhood of 0.002 ppm (parts per million) while PCB concentrations in lake water are 200 times lower, you would attribute the effect to

a. biomagnification. b. bioaccumulation. c. biodegradation.

d. biogeneration.

___6. All of the following statements about ecosystems are true EXCEPT:

a. Ecosystems refer to the physical components of the environment. b. Ecosystems may be large or small in size. c. Lake Erie is an ecosystem. d. Ecosystem boundaries may or may not be distinct.

___7. Environmental science is a. another term for ecology. b. based on physics and chemistry alone. c. a subdivision of biology. d. an interdisciplinary science.

___8. The Wilderness North is environmental assault. a. insensitive to b. resilient to c. vulnerable to d. unspoiled by

___9. The region referred to as the Agricultural Middle in your text encompasses parts of in Canada. a. Ontario b. Ontario and Quebec c. Manitoba and Saskatchewan d. Alberta, Saskatchewan and Manitoba

___10. The northern spotted owl has become an endangered species because of

a. toxic chemicals in their food. b. competition from another species. c. habitat alteration/destruction. d. hunting by humans.

1-D QUESTIONS FOR REVIEW, RESEARCH AND CRITICAL THINKING

1. Ecosystems are often characterized as self-sustaining and self-regulating. What do these words mean? Explain in terms of energy inputs, material cycles and ecosystem interactions.

2. On the premise that all ecosystems are self-sustaining and self-regulating, determine which of the following are ecosystems: (a) a home aquarium, (b) Metropolitan Toronto, (c) Lake Ontario, (d) the planet Earth. Do ecosystems have time scales associated with them? Discuss.

3. List three major environmental problems that are of national significance, and another three that are of global significance. Briefly explain why you consider each to be a serious problem, and describe what you as an individual can do to help alleviate it.

4. There are different approaches to solving environmental problems. Using the solid waste (generation and disposal) problem as an example, propose solutions based respectively on (a) an ecosystem approach, (b) a technology approach, (c) an economics approach, (d) a legislation approach. Are these approaches mutually exclusive? Which of these would be the approach of your choice, and why?

5. Why are we faced with so many serious environmental problems today? Is it largely because of a lack of political will and leadership at different levels of government? A disregard for public welfare on the part of industry and business? A lagging anti-pollution technology and scientific know-how? Existing economic and legal structures that are environmentally unsound and unfriendly? A world population that keeps growing and consuming more resources?... Is there a root cause? If so, identify it and justify your answer.

6. Using ideas derived from the ecosystem approach, compare electric cars and gasoline cars with respect to their impact on air pollution. Did electric cars come out clear winners in this comparison? Elaborate.

7. In the early 1950s eutrophication was emerging as a serious pollution problem in Lake Erie.

(a) What does eutrophication mean, literally and generally?

(b) What processes and what chemicals were responsible for the eutrophication in Lake Erie?

(c) Algal blooms were cited as one consequence of the eutrophication problem. What was the reason for the blooms to occur?

(d) Oxygen depletion was cited as another consequence of the eutrophication. Where was the oxygen depletion occurring - in the surface waters or bottom waters? And why would more algae (which are plants that release oxygen) in the Lake subsequently result in a depletion of dissolved oxygen in the water?

(e) Is eutrophication still a serious pollution problem in Lake Erie today? In the other Great Lakes? And in smaller lakes such as those in Ontario's cottage country? Comment.

8. Distinguish between bioaccumulation and biomagnification (also known as biological amplification). Why are persistent toxic chemicals such as PCBs often linked with bioaccumulation and biomagnification?

9. (a) The public has been advised by health agencies against eating very large trout from all five lakes. Why? If consumption of very large trout is to be avoided, should consumption of very large fish of other species be avoided as well? Explain.

(b) Suppose a 2-kg lake trout caught from one area of Lake Ontario contains 4 mg of PCBs. Guesstimate the number of milligrams of PCBs in a 5-kg lake trout taken from the same area of the Lake. Would it be close to 10 mg, considerably less than 10 mg, or considerably more than 10 mg? Give your reasoning.

10. Name three main environmental issues that were examined and discussed at the 1992 Earth Summit.

11. Compare environmental science and traditional science (e.g. biology, chemistry and physics). What are the major similarities and differences?

1-E WORKING WITH NUMBERS AND GRAPHS

1. Some quantities encountered in environmental science appear so enormous or so minuscule as to "boggle the mind." What general strategy would you suggest to render such quantities more meaningful? Illustrate your strategy by applying it to each of the following:

(a) Amount of water in the atmosphere: 1.3 x 10¹³ m³

(b) Global energy demand (1990): 3.9 x 10²⁰ J(oules) per year

(c) Dioxin concentration in lake trout from Lake Ontario (1987): 38 ppt (parts per trillion)

(d) Groundwater flow rate in a certain aquifer: 5 x 10^-7 m/s

(e) Canada's prime agricultural land area (1980s): 4.8 x 10¹¹ m²

(f) Worldwide topsoil loss (1990s): 23 billion tonnes per year

2. Few areas of basic mathematics are as widely used - and misused - in everyday life (and in environmental studies) as percent figures and percent calculations. When working with such figures and calculations, what basic rules should you be mindful of? What common pitfalls should you attempt to avoid?

3. Parts per million (ppm) and parts per billion (ppb) are often used as units for measuring pollutant concentrations. What exactly do these units represent? What ambiguities over the meaning of these units may sometimes arise? How are these units related to percent?

Chapter 1 Answers and Solutions

1-A T: Q.2, 3, 4, 7, 9

F: Q.1, 5, 6, 8, 10

Q.1 United Nations Conference on Environment and Development

Q.5 material input

Q.6 and with the physical components of the environment

Q.8 phosphates and nitrates

Q.10 in the Forested West of Canada

1-B 1c 2a 3d 4b 5g 6f 7e

1-C 1b 2d 3d 4c 5b 6a 7d 8c 9d 10c

1-D

1. Ecosystems are self-sustaining with respect to materials only. They do need energy inputs. Materials within ecosystems are continually cycled, and therefore supplies from outside are not needed. But the same can not be said about energy.

Ecosystems are self-regulating in the sense that interactions within an ecosystem tend to moderate excesses in either the positive or negative direction, thereby gradually restoring balance to the ecosystem.

2. All except Metro Toronto fulfill the requirements of self-sustaining and self-regulating, and hence are ecosystems.

Though not normally specified as such, ecosystems do have time scales associated with them. A small lake, for example, is an ecosystem only to the extent that a time scale of centuries is used.

3. Any reasonable answer is acceptable, e.g. acid deposition, toxic chemicals in Great Lakes waters and destruction of old-growth forests as national environmental problems; global warming, stratospheric ozone depletion and world population growth as global environmental problems.

Some ways an individual can help include being a lifelong student-teacher of environmental education; adopting a lifestyle of minimal environmental impact; and actively supporting environmental groups that promote sustainable development, restructuring of the economy, biodiversity preservation, population stabilization, pollution reduction and control, and other fundamental solutions to ultimate global environmental problems.

4. (a) Ecosystem approach: Practice the 3Rs.

(b) Technology approach: Use state-of-the-art high-efficiency incinerators.

(c) Economics approach: Impose surcharge on households with excessive garbage.

(d) Legislation approach: Require the use of recyclable containers. These approaches are not mutually exclusive - they could be used concurrently to complement each other. However, solutions based on technology, economics and legislation generally tend to be narrowly focused and neglect the big picture. For that reason, solutions based on an ecosystem approach would be preferable.

5. While we all love to put the blame on government, industry or the system, we are the root cause. We need an environmentally correct worldview and value system that translate into actions, lifestyle changes and new priorities.

6. If one looks at the big picture, one would find that electric cars are not "pollution-free." The electrical energy that propels these cars comes from electric power plants, most of which get their energy from burning coal or oil. So while the electric cars themselves may not emit any air pollutants, the power plants do. Perhaps insofar as air pollution is concerned, the dubious advantage of electric cars is that it changes the nature and location of the pollution: from photochemical smog in urban areas to acid deposition in neighboring regions.

7. (a) The word means good nutrition literally; in common usage, it refers to the overfertilization of a body of water by plant nutrients, resulting in abundant algae growth and oxygen deficiency in the water.

(b) The chemicals were phosphates and (to a lesser extent) nitrates. They entered the Lake as runoff from farmland and as effluent from sewage treatment plants.

(c) Phosphorus is usually the limiting factor in lake waters. As Lake Erie waters became overenriched with phosphates, the limiting factor was removed and algal bloom followed.

(d) Oxygen depletion was occurring in bottom waters where dead algae had accumulated. The dead algae didn't directly cause the oxygen depletion; the bacteria that were breaking them down did.

(e) Eutrophication is no longer a serious pollution problem in Lake Erie, nor is it in the other Great Lakes. However, eutrophication is a problem or emerging as a problem in some smaller lakes such as Lake Simcoe in Ontario. The reason: sewage treatment facilities have not caught up with population growths in the area.

8. Bioaccumulation refers to the buildup over time of toxic chemicals in the bodies of organisms (at a particular trophic level). Biomagnification refers to the increase in the concentration levels of these chemicals in organisms at a higher trophic level.

They are ubiquitous in the environment; they are very persistent and nonbiodegradable. Once ingested by an organism, they tend to accumulate in the fatty tissues of the body and build up to higher and higher levels. They then move up the food chain, resulting in biomagnification.

9. (a) Large trout have been found to contain levels of toxic chemicals higher than the maximum allowable concentrations, hence the advisories. Yes, as a general rule, consumption of very large fish of any species should be avoided.

(b) One should expect the 5-kg lake trout to contain considerably more than 10 mg of PCBs. Other factors being equal, the amount of toxic chemicals accumulated in the body is roughly proportional to the total amount of food consumed. As the age of the 5-kg trout is likely to be more than 2.5 times that of the 2-kg trout, and the daily amount of food required by the larger fish is likely to be higher than that required by the smaller fish, one should expect that the cumulative amount of food consumed by the 5-kg trout is much more than 2.5 times that consumed by the 2-kg trout.

10. Global climate change and greenhouse gas emissions, global deforestation, and the protection of biodiversity.

11. Similarities: Same physical and biological laws and principles; same analytical and data-based approach; same green planet and life thereof to study.

Differences: Environmental science is multidisciplinary and holistic; environmental science is a "soft" science; environmental science offers few perfect, ultimate solutions.

1-E

1. Divide (say by the world's population to make the number smaller), multiply (say by 1000 years to make the number larger), or somehow manipulate the number under consideration so as to link it with more familiar quantities or situations in our everyday life.

(a) It's about the same amount of water as contained in Lake Superior.

(b) It translates into about 11 barrels of oil per person per year

(c) You would need about 20 million lake trout to get just one spoonful of dioxin.

(d) It would take the groundwater a whole year just to move through a distance of 16 m.

(e) It's slightly more than half the size of Ontario.

(f) It's tantamount to losing all of the topsoil on about 5 million hectares of land, an area the size of Nova Scotia.

2. Basic rules:

a. Know the base. A figure like 5% is meaningless unless we know it's 5% of what. (A very small % figure may actually represent a huge quantity, and vice versa.) As any of the attributes, like sex, volume, weight, etc., of a given organism or physical quantity may be used as the base, the resulting % figure obviously depends on the choice of the base. Thus, if you are one of a group of one hundred people, by body count, you make up 1% of the group, but by body weight, you may not be 1%. As another example, "71% of the Earth is water" (as stated in some textbooks) can be a really confusing statement, when "71% of the Earth's surface is covered by water" is meant.

b. In computations involving %, use the decimal equivalent instead. Thus, rewrite 1.5% as 0.015 before doing a calculation on it.

c. Constituent parts should add up to 100%.

Pitfalls:

a. Be wary when additions or subtractions involving percents are performed, or when comparisons of them are made. If the base is not the same, then 1% of this simply isn't the same as 1% of that. For example, if the annual population increases of a certain city in five consecutive years are respectively 1.0%, 0.7%, 1.3%, 1.2%, and 0.8%, the total population increase for the 5-year period is not 5.0% (of the initial population).

b. When interpreting cumulative percent changes (e.g. "Tailpipe emissions of nitrogen oxides have been reduced by 75%."), ask questions like "Since when?", "Compared to what?" and "In absolute numbers, how large a quantity is it?" (For the above statement, the pertinent question might be: On average, how large a quantity of nitrogen oxides is still being emitted per car per kilometer driven?)

c. The kinds of growth we encounter in environmental studies are mostly of the compound growth type. Therefore, when figuring out the rate or the amount of growth, one has to use the compound interest formula or the exponential increase formula, rather than the simple interest formula.

3. Parts per million and parts per billion are simply extensions of parts per hundred (percent). 5 ppm, for example, means five parts of a certain pollutant/substance per 1,000,000 parts of polluted water (or air, or soil, or whatever). Occasionally, ambiguities arise over the meaning of parts. Is it grams, liters, the number of molecules, or what that are being used for counting and comparing? A common but not universal practice is to use mass units for counting in work involving liquids and solids, and to use volume units for counting in work involving gases.

To change from % to ppm, multiply the % value by 10,000. To change from % to ppb, multiply the % value by 10,000,000.

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