Environmental Science Answers for Chapter ExerciseThe first edition by Mony SuTopic 1 Earth Systems and Resources (10-15%)Chapter 02 Principles of Science and SystemsMultiple Choice Questions1 2 3 4 5 6 7 8 9 10B D D B E A AC A B11 12 13 14 15 16 17 18 19 20A C C A A A C D A A21 22 23A A DTrue / False Questions24 25 26F F FChapter 14 Geology and Earth ResourcesMultiple Choice Questions1 2 3 4 5 6 7 8 9 10C D E D A D B B B C11 12 13 14 15 16 17 18 19 20C B A C A E B AD B21 22 23 24 25 26 27 28 29 30E C D C B C A A D A31 32 33 34 35 36 37 38 39 40B A B EC C C A A B41ATrue / False Questions42 43 44 45 46T T T T FEssay Questions47.The diagram should look similar to Figure 14.8 on p. 307 in the textbook. Arrows should indicate that each rock type can be transformed into the other types, depending on the conditions.Chapter 15 Climate ChangeMultiple Choice Questions1 2 3 4 5 6 7 8 9 10A A C C DB B A B D11 12 13 14 15 16 17 18 19 20B A DC A BD C C D21 22 23 24 25 26 27 28 29 30B A BC A E A B B E31 32 33 34 35 36 37 38 39 40B A ACD A D C A A41 42 43 44 45 46 47 48 49 50A D D C C CB EC C51 52 53 54 55C A BD DTrue / False Questions56 57 58 59 60 61T T F F F FEssay Questions62.ENSO = El Nino Southern Oscillation.
El Nino years typically bring intense storms and heavy rain from California across the Midwestern states.
In general, the U.S. sees an increased amount of rainfall during El Nino years.
La Nina years normally bring hot, dry weather to most of the U.S.
The Pacific northwest (Washington, Oregon) usually has the reverse weather patterns. (Drier during El Nino and wetter during La Nina).63.The Kyoto Protocol is a treaty that was established in Kyoto, Japan in 1997. About 160 nations agreed to cut back on emissions of the main greenhouse gases to help with the problems associated with worldwide climate change. Even though the U.S. played an important role in leading the negotiations at Kyoto, it has never been ratified by the U.S. government. President Bush claims that it would be detrimental to our economy to doso.
Several big businesses in the U.S. have joined with four of the largest environmental groups to call for strong national legislation to ultimately achieve significant reductions of greenhouse gases. These are huge companies that can make a major impact (GE, Alcoa, BP Gas, etc.) if they are successful.
On an individual level, there are many things that can be done including: driving less, driving a fuel-efficient vehicle, planting trees, producing less waste (recycle or compost when possible), adjusting thermostats-especially when not at home, insulating your home, purchasing energy-efficient appliances, turning off lights, computers and other energy-consuming items when not in use, etc.Chapter 17 Water Use and ManagementMultiple Choice Questions1 2 3 4 5 6 7 8 9 10C A B A B C A C A A11 12 13 14 15 16 17 18 19 20D C A C C D B AE E21 22 23 24 25 26 27 28 29 30B D DC E B A C A A31 32 33 34 35 36D C D C B ATrue / False Questions37 38 39 40T F T FEssay Questions41.By comparison, both projects have the same purpose. That is to divert or transfer water from one region to another. In California, there is plentiful rainfall in the north, so excess water is pumped to the south. In China, it is the reverse. Southern China has plentiful water and will be pumping it to the north where it is scarcer.
In California, much of the original project was done rather underhandedly. In the early 1900s, land in northern California was quietly purchased by persons in power in Los Angeles. Eventually, they controlled over 90% of the water rights in the Owens Valley area of northern California. They built a huge aqueduct and transported the water to the south. So much water was transferred that the Owens River became dry for much of its course and Owens Lake, which was fed by the river, completely disappeared. In the 1940s, even more water was needed, so sources even further north were tapped to increase the supply. Another lake in this area lost half of its volume. This had serious environmental effects by decimating the population of brine shrimp that lived in the lake. This in turn decreased the number of waterbirds that relied on the shrimp as a food source. After many years of legal issues, the California Water Resources Board ruled in 1994 that LA must allow some water to replenish Lake Mono (the second lake affected). By 2014, the lake must be returned to its 1964 level. Some increase has been seen so far. The ecology also seems to be recovering slowly in this area.
In China, a huge multi-year, multi-billion dollar project is now underway to transfer water from southern to northern China. This will involve not one, but three separate routes to transfer the water to the needed regions. There are many problems and issues that will need to be dealt with. One issue is that water polluted by sewage and industrial waste is being transferred. Even though some areas are extremely dry, they are reluctant to accept this water. One of the routes will be extremely expensive and probably will not reach completion until at least 2050. This route will tunnel through mountains and over deep canyons. In addition, if global warming melts all of Tibet's glaciers, it may not be feasible in the long run. Environmental scientists worry that drawing from the Yangtze River will only worsen its pollution problems. Drawing water away from rivers on which millions rely only makes pollution problems worse. Downstream wetlands may also dry up, and ocean circulation may even be affected.42.Should include at least some of the following, but may include others as well.
▪ don't flush every time you use the toilet
▪ don't let the faucet run when washing hands, dishes, or brushing teeth
▪ take shorter showers
▪ use water-efficient plumbing fixtures
▪ check for leaky plumbing
▪ xeriscaping
▪ use recycled (gray) water for outside uses (if possible)—watering lawn, washing car, etc. ▪ run dishwasher only when fullTopic 2 The Living World (10-15%)Chapter 03 Matter, Energy, and LifeMultiple Choice Questions1 2 3 4 5 6 7 8 9 10E A B D E C C D E C11 12 13 14 15 16 17 18 19 20B E DC E A B E C A21 22 23 24 25 26 27 28 29 30B A B DC B C E A C31 32 33 34 35 36 37 38 39 40B DC AD A C B B E41 42 43 44 45 46 47 48 49 50E D D E A D E D A C51 52 53B E ATrue / False Questions54 55 56 57T T T FEssay Questions58.IV is false. There are many types of biogeochemical cycles, including carbon, nitrogen, phosphorus, and sulfur.59.Points awarded on depth and accuracy of answer. Answer should mention sunlight as the starting point for all energy and transfer of energy through living things in the foodchain/web (including energy lost as heat along each step of the pathway).60.Should include the following: carbon dioxide in the atmosphere, taken up by photosynthesis and released by cellular respiration (same in the oceans); carbon stored in the oceans; carbon deposits (dead organisms) forming calcium carbonate (limestone) on the ocean floor; carbon deposition from dead plants and animals millions of years ago formed today's fossil fuels.Chapter 04 Evolution, Biological Communities, and Species InteractionsMultiple Choice Questions1 2 3 4 5 6 7 8 9 10D C B B B A D DE A11 12 13 14 15 16 17 18 19 20B D BC BD C A A B21 22 23 24 25 26 27 28 29 30D A B D B B D D A D31 32 33 34 35 36 37 38 39 40A ABCD A A C A D41 42 43 44 45 46 47 48E C A E A E B BChapter 05 BiomesMultiple Choice Questions1 2 3 4 5 6 7 8 9 10B C A B C D B B D D11 12 13 14 15 16 17 18 19 20D C D C B BE B A C21 22 23 24 25 26 27 28 29 30D A B D C CE E D D31 32 33 34 35 36 37 38 39 40C B B BD B A A B A41 42 43 44 45 46 47 48 49 50C E E B C B B C C C51DTrue / False Questions52 53 54 55 56F T F T TChapter 11 BiodiversityMultiple Choice Questions1 2 3 4 5 6 7 8 9 10C CD AE C A A C D11 12 13 14 15 16 17 18 19 20D C D A B C C BE B21 22 23 24 25 26 27 28 29 30A D C CBC AD D B31 32 33 34 35 36 37 38 39 40A D D D A DB BC D41 42 43 44 45 46 47 48D B A B CE B ATrue / False Questions49 50 51 52 53T F T T FEssay Questions54.Should include some of the following, but may include others as well.
1) We have a large variety of food sources to choose from—all types of grains, starches, fruits, vegetables, seafood, and meat.
2) Pollinators provide us with many of our food sources, so they are also extremely important. They include birds, insects, and bats.
3) Bacteria and fungi provide us with many antibiotics.
4) Bacteria and fungi are also very beneficial as decomposers—cycling of nutrients.
5) Many plants have provided us with numerous drugs used to treat all types of diseases and illnesses. There are many discovered and undiscovered plants that may have medicinal potential.
6) Organisms provide us with ecological services that are invaluable to us—things like soil formation, water purification, production of oxygen, etc.
7) Organisms provide us with the opportunity for recreation—camping in a forest, fishing, horseback riding, etc.
8) Biodiversity can be economically beneficial. Many countries are now turning to ecotourism—making income by maintaining the natural environment for visitors to enjoy.55.Will vary depending upon the region you live in.Topic 3 Population (10-15%)Chapter 06 Population BiologyMultiple Choice Questions1 2 3 4 5 6 7 8 9 10A D CB A B ECD B11 12 13 14 15 16 17 18 19 20A EBC B A E E C E21 22 23 24 25 26 27 28 29 30A C ABCDE C E D31 32 33 34 35 36D B A C D ATrue / False Questions37 38 39 40T F F TChapter 07 Human PopulationsMultiple Choice Questions1 2 3 4 5 6 7 8 9 10C E E E E E A B A C11 12 13 14 15 16 17 18 19 20C A B A B E CD C A21 22 23 24 25 26 27 28 29 30C E B A A E E B B C31 32 33 34 35 36 37 38 39 40A B D B D C A B A E41 42 43 44 45 46 47 48 49 50B E DC E A B A A CD E B E C A D D E BTrue / False Questions61 62 63 64F T T TEssay Questions65.General trends, not numbers, should be included. There are three basic trends:
1) Rapidly growing countries - characterized by high birth and death rates, high fertility rates, and typically, high emigration rates
2) Stable populations - characterized by low birth and death rates, low fertility rates, and low emigration rates
3) Negative growth countries - characterized by death rates higher than birth rates, (however, both are low), extremely low fertility rates, (typically less than the 2.1 replacement rate) and low emigration rates66.x-axis should be labeled with increasing years of education, y-axis should be labeled with increasing rates of infant mortality. Graph should show a decline in infant mortality rates as years of education increase. Please include X and Y axis label, appropriate scales on the axes, and a legend.Topic 4 Land and Water Use (10-15%)Chapter 09 Food and HungerMultiple Choice Questions1 2 3 4 5 6 7 8 9 10C CD B D DE A C AE E B D A C C D D A21 22 23 24 25 26 27 28D C D B AE A DTrue / False Questions29 30 31 32 33 34T F F T T FEssay Questions35.Genetic recombination involves removing specific genes from one organisms and inserting them into another. This type of technology allows for many advantages. Someone who sees the positive benefits of this technology would be a technological optimist. Scientists working in this field would obviously see the benefits; opponents would most likely not be those in the field of genetic engineering. There are many benefits including: improved crops (yield, pest and disease resistance, salt tolerance, etc.), vaccines could be placed in foods like bananas and potatoes, insulin and other hormones can be mass-produced relatively cheaply.Chapter 10 Farming: Conventional and Sustainable PracticesMultiple Choice Questions1 2 3 4 5 6 7 8 9 10A B B E C D C E E A11 12 13 14 15 16 17 18 19 20B B EC C B E B C B21 22 23 24 25 26 27 28 29 30B E D D BC E B E B31 32 33 34 35 36 37 38 39 40A D AB B BC C B E41 42 43 44 45 46 47 48 49 50B D BC B A C B A AD B CE E D B A E A61 62 63 64 65 66 67 68 69 70B AC E C A E C E B71 72 73 74C D E BTrue / False Questions75 76 77 78 79 80T T T F F TEssay Questions81.Industrial farming produces very large amount of foods—in fact more than enough to feed the world's population (if distributed evenly).However, a large amount of this food goes to waste. The use of pesticides in industrial farming is very high and this results in many environmental problems—Poisoning nontarget species, including beneficial predators, pesticide resistance, reproductive problems in nontarget species, persistence and mobility—all can affect humans and animals thousands of miles away. Pesticides are also responsible for a myriad of human health problems. Organic farming does not result in as great a yield as industrial.However, it is much more eco-friendly. It leaves the soil in much better condition and since prices paid for organic products are higher than conventional, net returns are typically higher with organic crops. Since no pesticides are used, there are no negative health effects or other negative impacts associated with this type of farming.82.Should include at least some of the following, but may include others.
▪ buy organic—should contain no pesticides
▪ wash and scrub all fresh fruits and vegetables to remove residues
▪ peel fruits and vegetables when possible to remove all traces of pesticides
▪ throw away the outer leaves of leafy vegetables to remove highest concentration of pesticides
▪ store food carefully to avoid mold or bacterial growth—these organisms can produce their own toxins
▪ cook foods that you suspect have pesticides to break down residues
▪ trim the fat from meat, chicken, and fish—fat contains the highest concentrations of pesticides
▪ reduce the amount of meat in your diet to reduce your pesticide intake
▪ don't pick and eat wild berries that may have been sprayed—it's better to be safe—wash them first
▪ grow your own fruits and vegetables—then you know exactly where the food came from! Chapter 12 Biodiversity: Preserving LandscapesMultiple Choice Questions1 2 3 4 5 6 7 8 9 10D B C D D B A A C A11 12 13 14 15 16 17 18 19 20A B C B C A C D A B21 22 23 24 25 26 27 28 29 30D E B C C C B C C B31 32 33 34 35 36 37 38 39 40B A E B B D D EC B41 42 43 44C D C BTrue / False Questions45 46 47T T TEssay Questions48.Old growth forests have the following characteristics: very high levels of biodiversity, many unique species live only in old-growth forests, they accumulate more total biomass in standing vegetation per unit area than any other ecosystem, little or no erosion, nutrient-rich soil, only a small percentage remains and large percentages of that are scheduled to be harvested, the most valuable of these forests are protected (at least for now).
Tree farms have the following characteristics: the types and sizes of trees can vary depending upon the cutting technique that is used; however, most are made up of one type of tree, most of which are about the same age and size (clear-cutting), typically soil erosion is prevalent due to lack of undergrowth, rotting logs, and other vegetation, soil is also typically nutrient-poor (no vegetation to be recycled—everything is removed), very little biodiversity due to little variation in habitat, alternative methods of cutting such as selective cutting are much better environmentally—decreases erosion, improves soil quality, increases biodiversity among other benefits.49.Brazil has the largest amount of land in protected status as of now. The majority of this protected land is in the Amazon basin. Nine new protected areas in the northern Amazon basin were established in 2006 (along the borders of Suriname and Guyana). About half of this newly protected land will be strictly protected and will create the largest tropical forest reserve in the world.
In contrast to this is the Pantanal. This is the world's largestwetland/savanna complex (somewhat similar to the Florida everglades). Some of the regions of the Pantanal have even greater amounts of biodiversity than the Amazon basin. However, most of this region is privately owned and so far, very little of it has any protected status.Chapter 13 Restoration EcologyMultiple Choice Questions1 2 3 4 5 6 7 8 9 10D C AE E A E D A B11 12 13 14 15 16 17 18 19 20C A E E B BD C A A21 22 23 24 25 26 27 28 29 30A C D E A A C E A A31 32 33 34D D B ATrue / False Questions35 36 37 38 39T F F T TEssay Questions40.The intent of both is obviously to preserve the prairie. However, it is being approached in two completely different ways. The Nature Conservancy (TNC) is cooperating with local ranchers and allowing them to continue grazing cattle on most of the land (which TNC owns) in exchange for specific conservation measures including protection of prairie dog colonies and sage grouse nests. They must also control weed growth. TNC's approach is that by keeping ranch families working on the land, it preserves their lifestyle and at the same time, preserves the biodiversity of the Great Plains. Close by, the American Prairie Foundation (APF) is going about preservation by a completely different route. They have purchased approximately the same amount of land as TNC (close to 60,000 acres). Instead of continuing to allow cattle ranching, they will remove all fences and buildings and return the area to wilderness. They also plan to return wildlife including elk, bison, wolves and grizzly bears to the land. Nearby ranchers are not thrilled with the prospect of the predators being returned, as they feel their livestock will be threatened. Many also are not happy that the funding is coming mainly from Wall Street or Silicon Valley in California. They are upset that people with money from the outside are forcing changes upon them. They worry about restrictions that may be placed on the land. The APF defends its side by saying that tourism, bird-watching, and hunting will be allowed on nearly all of its lands and that this will bring in more income than raising cattle.41.Should include some of the following:
1) To reduce sediment influx (erosion from stream banks or other areas), several different methods may be employed including planting ground cover on banks or uplands; gullies that empty into the stream may be filled with rocks or brush; barriers can be used to deflect the current away from the stream banks or to trap sediment (these may include weirs, vanes, dams, logs, bundled brush, root wads, etc.)—these can actually be beneficial in carving out deep pools in the stream bottom, which provide excellent habitat for fish and other organisms; stabilizing stream banks—should be no more than 45 degrees to minimize erosion; soil can be held in place by plants, rocks, or other ground cover; if there is not enough space to recontour, steep banks will need to be supported by rock walls, riprap, or embedded tree trunks.Chapter 22 Urbanization and Sustainable CitiesMultiple Choice Questions1 2 3 4 5 6 7 8 9 10D D AE E B C B E A11 12 13 14 15 16 17 18 19 20C B CD C A B A B C21 22 23 24 25 26 27 28 29 30C A B A B A A C E E31 32 33 34C C B DTrue / False Questions35 36 37 38 39T T F F TEssay Questions40.Push factors: no jobs, lack of food, inadequate housing, political conflicts, racial conflicts, religious conflicts
Pull factors: opportunity for education, variety of jobs, entertainment, freedom, social mobility, prestige, power41.Should contain some of the following information and may include others as well.
Compare: Both are communities of living things along with the physical environment; both are affected by the abiotic conditions; both have a constant flow of matter and energy cycling through both living and non-living; both involve niches; both have fairly distinctboundaries.
Contrast: Cities involve only humans—other species may live there, but are not an integral part of the functioning city; people not affected so much by abiotic factors (e.g., temp. is regulated by A/C and heating, go to work whether it is raining or snowing); many human activities and inputs are part of a city, but not an ecosystem (city foundation, drainage, sewage, pollution, garbage, etc.); infrastructure completely different—man-made in cities, natural in ecosystems.Chapter 23 Ecological EconomicsMultiple Choice Questions1 2 3 4 5 6 7 8 9 10E C E A C B B C C D11 12 13 14 15 16 17 18 19 20C A CD D A BE B E21 22 23 24 25 26 27 28 29 30D A D C A B BE B D31 32 33 34 35 36 37 38 39 40C E B C A ADE A E41 42 43 44 45 46 47 48A AB E D A B ATrue / False Questions49 50 51 52 53T T T F FEssay Questions54.Should look like Fig. 23.7 on p. 521 in textbook.55.Should include some of the following answers:
Economist: focus on human resources (buildings, roads, labor); natural systems essential but externalized; manufactured capital is regarded as scarce and valuable; natural capital is regarded as plentiful and cheap; as one natural resource becomes scarce, a substitute will easily be found; based on supply and demand.
Ecologist: focus on value of natural services; natural services are internalized; manufactured capital is very large (not really valuable) and puts stresses on natural resources; recycling is important; limited supplies of natural capital, which is valuable and often fragile.Topic 5 Energy Resources and Consumption (10–15%)Chapter 19 Conventional EnergyMultiple Choice Questions1 2 3 4 5 6 7 8 9 10A C EB D D E A D E11 12 13 14 15 16 17 18 19 20A A CB D A D A B B21 22 23 24 25 26 27 28 29 30D C A D AE A E E B31 32 33 34 35 36 37 38 39 40C A BD A B D B D C41 42 43 44 45A B C E BTrue / False Questions46 47 48 49 50 51F F T T F FEssay Questions52.In your evaluation, provide the pros and cons and the context in which each energy source would work best.53.Answers should contain at least some of the following but may contain others.Chapter 20 Sustainable EnergyMultiple Choice Questions1 2 3 4 5 6 7 8 9 10B BC AD C C B A B11 12 13 14 15 16 17 18 19 20E B D E C C C D C C21 22 23 24 25 26 27 28 29 30E E B E A C E A C B31 32 33 34 35A A C A BTrue / False Questions36 37 38 39 40 41F T T F F FEssay Questions42.Solar energy would be the best option for this situation. The new amorphous silicon collectors can be made into lightweight, paper-thin sheets that can be layered right on to roof tiles. A tropical country implies that it is warm and sunny year-round, providing the optimalconditions for solar collection. These collectors are already currently being used in remote places without access to conventional power, so this would be a perfect place for this technology. Homes and offices can be built without power plants and power lines; no fuels would need to be purchased; and you would have no monthly energy bills. Prices of solar electricity are dropping each year and will be competitive with conventional power (fossil fuels) by 2020. Even though the start-up cost may be more currently, in the long run the solar power will more than pay for itself.43.Should contain some of the items listed in the table below.Topic 6 Pollution (25-30%)Chapter 08 Environmental Health and ToxicologyMultiple Choice Questions1 2 3 4 5 6 7 8 9 10D E D A C A B D A A11 12 13 14 15 16 17 18 19 20B ACD B C B B A D21 22 23 24 25 26 27 28 29 30D E C D B A A E D A31 32 33 34 35 36 37 38 39 40D A B A B DE E C A41 42 43 44 45 46 47 48 49 50B C A B A E D C B C51 52 53 54 55C D E C ATrue / False Questions56 57 58 59 60T T T F TEssay Questions61.You would most likely be worried because: (should mention at least one from each category)
1) They may cause kidney and/or liver damage.
2) They may cause some types of cancer.
3) They can act as endocrine disrupters, affecting sex hormones; this can lead to reproductive abnormalities and decreased fertility as well as low sperm counts and decreased sperm motility.62.Should look like Fig. 8.16 in textbook (see explanation for the below figure).Chapter 16 Air PollutionMultiple Choice Questions1 2 3 4 5 6 7 8 9 10E A B C D A B C B A11 12 13 14 15 16 17 18 19 20E C C B A E A B D C21 22 23 24 25 26 27 28 29 30A A D C D D EB A D31 32 33 34 35 36 37 38 39 40C E E B AD CE A C41 42 43 44 45 46 47 48 49B BC BD B D B ATrue / False Questions50 51 52 53 54 55 56 57F F F F T F F FEssay Questions58.Both are formed by atmospheric oxygen (O2) combining with an atom of singlet oxygen (O).
In the troposphere, ozone is a major component of smog. It is formed as a photochemical oxidant, resulting mainly from too many hydrocarbons in the air. It is a strong oxidizing agent and damages vegetation and buildings. It is also an irritant to the lungs and eyes. It can be very harmful to persons with underlying respiratory conditions, so itis considered a pollutant.
Its role in the stratosphere is completely different. It acts as a UV filter, providing earth with a "natural" shield from incoming solar radiation. When it becomes depleted, due mainly to CFCs, excess UV makes it through the ozone layer. This results in increased incidence of skin cancer and eye damage in humans. It is also harmful to crops, which may show decreased productivity.Chapter 18 Water PollutionMultiple Choice Questions1 2 3 4 5 6 7 8 9 10C ED C A B A A C C11 12 13 14 15 16 17 18 19 20C B A B CD B C A B21 22 23 24 25 26 27 28 29 30D CE E D A E E E A31 32 33 34 35 36 37 38 39 40B C A E D A A C A B41 42D ETrue / False Questions43 44 45 46F F F TEssay Questions47.Point
▪ Examples include factories, power plants, sewage treatment plants, underground coal mines, and oil wells
▪ Pollution is discharged from specific locations (e.g., drain pipes, smoke stacks, ditches, sewer outfalls)
▪ Discrete and identifiable, so are relatively easy to monitor and regulate
▪ Generally feasible to divert effluent from the waste stream and treat it before it is released into the environment Nonpoint
▪ Examples include runoff from farm fields and feedlots, golf courses, lawns and gardens, construction sites, logging areas, roads, streets, and parking lots
▪ There is no specific location where they discharge, so it can end up in water anywhere
▪ Typically are scattered or diffuse
▪ Amount of runoff is seasonal (varies with times and amounts of precipitation); heavy rainfalls may flush or carry a lot of pollutants into lakes, rivers, and other bodies of water at one time
▪ Much more difficult to monitor, regulate, and treat48.BOD is one way to measure the amount of bacteria in a water sample. Organic wastes, including sewage, paper pulp, or food, are very rich in certain nutrients—especially nitrogen and phosphorus. Once in aquatic ecosystems, these nutrients stem the growth of decomposing bacteria. These bacteria consume large amounts of oxygen. The BOD can give us an approximation of the amount of organic waste in the water based on the oxygen content. The effects of oxygen-demanding wastes on bodies of water depend on the volume, flow, and temperature of the water. In general, a characteristic decline in oxygen is seen downstream from a point source (e.g., discharge pipe). This is called the oxygen sag. Farther downstream, levels of oxygen will eventually return to normal.
A diagram similar to Fig. 18.7 on p. 402 in the text (showing the relationship between BOD and oxygen sag) should be drawn with appropriate labels. Zones, oxygen levels, and types of organisms may be included in this diagram.。
