• 76 questions

APES Unit 8 Practice Test

Unofficial practice for Unit 8 of AP Environmental Science, Aquatic and Terrestrial Pollution, from runoff to landfills.

Which of these is a nonpoint source of pollution?

Pick an answer, then press Check answer. Then you see Correct or Not quite, with the reason. Keys: A to D pick, Enter checks.

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Unofficial practice questions, not affiliated with the College Board. Bank checked October 14, 2026.

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All 76 questions

Topic 8.1: Sources of pollution 5

  • After very heavy rain a combined sewer system overflows, and runoff mixed with raw sewage goes untreated into the nearest waterbody. How is this overflow classed? NOAA National Ocean Service, Nonpoint Source Pollution tutorial, "Point Source"; course topic 8.1
  • The EPA defines a point source as "any single identifiable source of pollution from which pollutants are discharged". Which of these fits? NOAA National Ocean Service, Nonpoint Source Pollution tutorial, "Point Source"; course topic 8.1
  • Most nonpoint source pollution occurs as a result of what? NOAA National Ocean Service, Nonpoint Source Pollution tutorial, "Nonpoint Source"; course topic 8.1
  • Which of these is a nonpoint source of pollution? College Board, AP Environmental Science Course and Exam Description, topic 8.1, essential knowledge STB-3.A.2
  • Why is nonpoint source pollution difficult to control? NOAA National Ocean Service, Nonpoint Source Pollution tutorial, "Nonpoint Source"; course topic 8.1
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Topic 8.2: Human impacts on ecosystems 12

  • A stream holds 8 mg/L of dissolved oxygen above a sewage outfall and 2 mg/L just below it. By what percent did the dissolved oxygen fall? Worked from the numbers in the question; course topic 8.2
  • After an oil spill at sea, what do the components of oil that sink do? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.3
  • Below about what concentration of dissolved oxygen is water defined as hypoxic? U.S. Geological Survey, Water Science School, "Dissolved Oxygen and Water"; course topic 8.2
  • Besides being unsightly, what harm does litter do when it reaches aquatic ecosystems? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.8
  • How can heavy metals from mining and the burning of fossil fuels affect people? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.7
  • Increased sediment in a waterway reduces light infiltration. Which organisms does that affect, by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.9
  • Oil that washes up on a beach has economic consequences. Which industries does the course outline name? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.4
  • Organisms have an optimum range for each environmental factor. What may an organism experience outside that range? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.1
  • What do corals do when the water becomes too warm? NOAA National Ocean Service, "What is coral bleaching?"; course topic 8.2
  • What is an oxygen sag curve? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.6
  • When elemental mercury enters an aquatic environment, what do bacteria in the water convert it to? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.10
  • Which factors does the course outline name as damaging coral reefs? College Board, AP Environmental Science Course and Exam Description, topic 8.2, essential knowledge STB-3.B.2

Topic 8.3: Endocrine disruptors 3

  • What are endocrine disruptors? College Board, AP Environmental Science Course and Exam Description, topic 8.3, essential knowledge STB-3.C.1
  • What is one way a chemical can disrupt the endocrine system, according to the EPA? U.S. Environmental Protection Agency, "Overview of Endocrine Disruption"; course topic 8.3
  • Which effects of endocrine disruptors on fish and other species does the course outline name? College Board, AP Environmental Science Course and Exam Description, topic 8.3, essential knowledge STB-3.D.1

Topic 8.4: Wetlands and mangroves 5

  • The EPA says wetlands function as natural sponges. What does that describe? U.S. Environmental Protection Agency, "Why are Wetlands Important?"; course topic 8.4
  • How does the course outline define a wetland? College Board, AP Environmental Science Course and Exam Description, topic 8.4, essential knowledge STB-3.E.1; U.S. Environmental Protection Agency, "What is a Wetland?"
  • Where do mangroves grow? Wikipedia, "Mangrove"; course topic 8.4
  • Which ecological services of wetlands does the course outline list? College Board, AP Environmental Science Course and Exam Description, topic 8.4, essential knowledge STB-3.E.2; U.S. Environmental Protection Agency, "Why are Wetlands Important?"
  • Which threats to wetlands and mangroves does the course outline name? College Board, AP Environmental Science Course and Exam Description, topic 8.4, essential knowledge STB-3.E.3

Topic 8.5: Eutrophication 5

  • How does an oligotrophic waterway compare with a eutrophic one? College Board, AP Environmental Science Course and Exam Description, topic 8.5, essential knowledge STB-3.F.4
  • What is a hypoxic waterway? College Board, AP Environmental Science Course and Exam Description, topic 8.5, essential knowledge STB-3.F.3; NOAA National Ocean Service, "What is a dead zone?"
  • When does eutrophication occur? College Board, AP Environmental Science Course and Exam Description, topic 8.5, essential knowledge STB-3.F.1
  • When the excess algae of a eutrophic estuary decompose, they produce large amounts of carbon dioxide. What does that do to the seawater? NOAA National Ocean Service, "What is eutrophication?"; course topic 8.5
  • Which order of events describes eutrophication? College Board, AP Environmental Science Course and Exam Description, topic 8.5, essential knowledge STB-3.F.2

Topic 8.6: Thermal pollution 3

  • Besides temperature, what lowers dissolved oxygen in water as organic matter decays? U.S. Geological Survey, Water Science School, "Dissolved Oxygen and Water"; course topic 8.6
  • What is thermal pollution? College Board, AP Environmental Science Course and Exam Description, topic 8.6, essential knowledge STB-3.G.1
  • Which water can hold more dissolved oxygen? U.S. Geological Survey, Water Science School, "Dissolved Oxygen and Water"; course topic 8.6

Topic 8.7: Persistent organic pollutants 4

  • How can a persistent organic pollutant affect wildlife far from where it was used? U.S. Environmental Protection Agency, "Persistent Organic Pollutants: A Global Issue, A Global Response"; course topic 8.7
  • In which year did the United States ban the agricultural use of DDT? Wikipedia, "DDT"; course topic 8.7
  • Why can persistent organic pollutants build up in the bodies of organisms? College Board, AP Environmental Science Course and Exam Description, topic 8.7, essential knowledge STB-3.H.2
  • Why do persistent organic pollutants not break down easily in the environment? College Board, AP Environmental Science Course and Exam Description, topic 8.7, essential knowledge STB-3.H.1

Topic 8.8: Bioaccumulation and biomagnification 5

  • A pollutant measures 0.02 ppm in zooplankton and 5 ppm in the fish at the top of the same food chain. How many times more concentrated is it in the top fish? Worked from the numbers in the question; course topic 8.8
  • What is bioaccumulation? College Board, AP Environmental Science Course and Exam Description, topic 8.8, essential knowledge STB-3.I.1
  • When a persistent substance is biomagnified in a food chain, which effects can appear in top carnivores? College Board, AP Environmental Science Course and Exam Description, topic 8.8, essential knowledge STB-3.J.1
  • Which birds showed the eggshell thinning that was tied to DDT? Wikipedia, "DDT"; course topic 8.8
  • Which three substances does the course outline name as bioaccumulating with significant environmental impacts? College Board, AP Environmental Science Course and Exam Description, topic 8.8, essential knowledge STB-3.J.3

Topic 8.9: Solid waste disposal 8

  • NOAA says the "garbage patch" of the North Pacific is not an island of trash that can be seen from the air. What is much of the debris? NOAA National Ocean Service, "What is the Great Pacific Garbage Patch?"; course topic 8.9
  • Used rubber tires are not accepted in sanitary landfills. What problem can piles of them cause? College Board, AP Environmental Science Course and Exam Description, topic 8.9, essential knowledge STB-3.L.3
  • What are the benefit and the drawback of incineration, by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.9, essential knowledge STB-3.L.2
  • What is electronic waste, or e-waste? College Board, AP Environmental Science Course and Exam Description, topic 8.9, essential knowledge STB-3.K.3
  • What is landfill gas roughly made of? U.S. Environmental Protection Agency, Landfill Methane Outreach Program, "Basic Information about Landfill Gas"; course topic 8.9
  • What is leachate? U.S. Environmental Protection Agency, "Municipal Solid Waste Landfills"; Wikipedia, "Leachate"; course topic 8.9
  • What is solid waste, by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.9, essential knowledge STB-3.K.1
  • Which list gives the parts of a sanitary municipal landfill named in the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.9, essential knowledge STB-3.K.4

Topic 8.10: Waste reduction methods 7

  • A school composts 12 kg of food scraps on each of its 180 school days. How much does it keep out of the landfill in a school year? Worked from the numbers in the question; course topic 8.10
  • A town produces 500 tons of solid waste each week and recycles 30% of it. How many tons are left for other disposal? Worked from the numbers in the question; course topic 8.10
  • How can gases from the decomposition of organic material in a landfill be put to use? College Board, AP Environmental Science Course and Exam Description, topic 8.10, essential knowledge STB-3.M.6
  • Recycling reduces the global demand on minerals. What drawback does the course outline name? College Board, AP Environmental Science Course and Exam Description, topic 8.10, essential knowledge STB-3.M.2
  • What can the product of composting be used as? College Board, AP Environmental Science Course and Exam Description, topic 8.10, essential knowledge STB-3.M.3
  • Which range of landfill mitigation strategies does the course outline give? College Board, AP Environmental Science Course and Exam Description, topic 8.10, essential knowledge STB-3.M.5
  • Why must e-waste be disposed of properly? College Board, AP Environmental Science Course and Exam Description, topic 8.10, essential knowledge STB-3.M.4

Topic 8.11: Sewage treatment 4

  • Before treated water is discharged, it is exposed to a disinfectant to kill bacteria. Which three does the course outline name? College Board, AP Environmental Science Course and Exam Description, topic 8.11, essential knowledge STB-3.N.4
  • What does tertiary treatment of sewage do? College Board, AP Environmental Science Course and Exam Description, topic 8.11, essential knowledge STB-3.N.3
  • What happens in the primary treatment of sewage? College Board, AP Environmental Science Course and Exam Description, topic 8.11, essential knowledge STB-3.N.1
  • Why is the tank aerated during the secondary treatment of sewage? College Board, AP Environmental Science Course and Exam Description, topic 8.11, essential knowledge STB-3.N.2

Topics 8.12 and 8.13: LD50 and dose response 4

  • A chemical has an LD50 of 20 mg per kg of body mass for a test species. What total dose does that correspond to for an animal of 0.5 kg? Worked from the numbers in the question; course topic 8.12
  • In which units is an LD50 usually expressed? Wikipedia, "Median lethal dose"; course topic 8.12
  • What does a dose response curve describe? College Board, AP Environmental Science Course and Exam Description, topic 8.13, essential knowledge EIN-3.B.1
  • What does lethal dose 50% (LD50) mean? College Board, AP Environmental Science Course and Exam Description, topic 8.12, essential knowledge EIN-3.A.1

Topic 8.14: Pollution and human health 4

  • Elevated levels of which pollutant does the course outline tie to respiratory problems and reduced lung function? College Board, AP Environmental Science Course and Exam Description, topic 8.14, essential knowledge EIN-3.C.4
  • Exposure to which material is the main cause of mesothelioma, by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.14, essential knowledge EIN-3.C.3
  • Which disease does the course outline tie to untreated sewage in streams and rivers? College Board, AP Environmental Science Course and Exam Description, topic 8.14, essential knowledge EIN-3.C.2
  • Why can it be difficult to establish cause and effect between a pollutant and a human health issue? College Board, AP Environmental Science Course and Exam Description, topic 8.14, essential knowledge EIN-3.C.1

Topic 8.15: Pathogens and infectious diseases 7

  • As equatorial-type climate zones spread north and south, what does the course outline say happens to pathogens and their vectors? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.3
  • Besides malaria, which two diseases in the course outline reach humans through bites from infected mosquitoes? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.8
  • How does malaria reach humans, by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.7
  • What kind of illness is Middle East Respiratory Syndrome (MERS), by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.10
  • Which disease in the course outline is a bacterial disease contracted from infected water? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.12
  • Which part of the body does tuberculosis typically attack? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.6
  • Why do infectious diseases often find opportunities to spread in low-income areas, by the course outline? College Board, AP Environmental Science Course and Exam Description, topic 8.15, essential knowledge EIN-3.D.4

How this list was compiled: Our own questions, written to Unit 8 (Aquatic and Terrestrial Pollution, topics 8.1 to 8.15) of the College Board's AP Environmental Science Course and Exam Description, effective fall 2026, https://apcentral.collegeboard.org/media/pdf/ap-environmental-science-course-and-exam-description.pdf, read 2026-10-14. Each fact was read on 2026-10-14 in the public page named under its question: an essential knowledge statement of the course description; a page of the NOAA National Ocean Service, the U.S. Geological Survey Water Science School or the U.S. Environmental Protection Agency; or a Wikipedia article. Answers that are worked out were recomputed. Licence: Own work.

How it works

This APES Unit 8 practice test has 76 questions of our own on Aquatic and Terrestrial Pollution: water pollution, solid waste, sewage treatment, toxicity and disease. It is unofficial and not affiliated with the College Board, the owner of the AP exams.

Read the full guide

What Unit 8 covers

The College Board's course description, effective fall 2026 and read October 14, 2026, gives Unit 8 fifteen topics. Water comes first here: sources of pollution (5 questions), human impacts on ecosystems (12), endocrine disruptors (3), wetlands and mangroves (5), eutrophication (5) and thermal pollution (3). Then come persistent pollutants and biomagnification (9), solid waste and waste reduction (15), sewage treatment (4), LD50 and dose response (4), and health and pathogens (11). The spread is ours.

Sources you can open

Each answer cites an essential knowledge statement of the course description, a NOAA, USGS or EPA page, or a Wikipedia article. The disease questions repeat only what the outline states: practice for an exam, not medical advice.

  • A point source is one you can point to, such as a pipe or a smokestack. Runoff from many places is nonpoint.
  • For a percent change, divide the change by the starting value, then multiply by 100.

Questions and answers

What is Unit 8 in APES?

Aquatic and Terrestrial Pollution, fifteen topics from sources of pollution to pathogens. It carries 7 to 10% of the multiple-choice section, by the course description, which suggests about 19 to 20 class periods for it.

What does an APES Unit 8 study guide cover on water?

Topics 8.1 to 8.6 and 8.11: point and nonpoint sources, oil spills, dead zones and the oxygen sag curve, endocrine disruptors, wetlands and mangroves, eutrophication, thermal pollution, and the three stages of sewage treatment.

What math is in APES Unit 8?

Topics 8.2 and 8.10 ask for a worked answer with its units, such as a percent change or the amount of waste recycled, and topic 8.12 uses LD50, a dose per kilogram of body mass.

What is the difference between bioaccumulation and biomagnification?

Bioaccumulation is the build-up of a substance in the cells of one living organism. Biomagnification is the increase in its concentration at each higher trophic level of a food chain or food web.

Is this the College Board's Unit 8 test?

No. Its Progress Check for Unit 8, about 35 multiple-choice questions and one free-response question by the description, is assigned in AP Classroom. The 76 questions here were written for this page and copy none of it.

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