APES midterm Questions with Correct Answers (Grade A+)
Question 1: Natural Sources of water pollution
Answer: oil seeps, erosion, weathering (metals), salt concentrations, radioactivity, volcanoes
Question 2: Difference between point and non-point anthropologic causes of water pollution
Answer: -point-causes are direct and traceable -non point-scattered, no specific location of discharge
-NONpoint is harder to control because it is harder to regulate and multiple causes blend together PLUS the
timing is irregular and is affected by rain/seasons
Question 3: Point sources of pollution
Answer: sewage treatment, mining, factories, power plants, tail pipes of car, leaking septic tanks
Question 4: nonpoint source pollution
Answer: lawns/gardens (fertilizers)gold, crops, feedlots/pastures, untreated sewage, roads, construction
sites, atmospheric deposition
Question 5: Atmospheric deposition
Answer: -a certain type of nonpoint pollution of contaminants carried by air currents and precipitated into
watesheds or directly onto surface waters -Like: insecticides, herbicides, NOxs
Question 6: Life at low levels
Answer: sludge worms, midge/mosquito larvae, etc
Question 7: BOD
Answer: stands for biochemical oxygen demand (demanded by the bacteria)
Question 8: Dissolved oxygen measurements indirectly measure BOD. They are often used because they
are easier, quicker, and cheaper. Still it is an indirect measurement. What other factors does DO
depend on?
Answer: -Eutrophication=low DO -Summer=Low DO -Pollution -Temperature high=Low DO -Aeration
high=DO High
Question 9: Clean Zone Macroinvertebrates
Answer: mayfly, stone fly, caddis fly larvae (see graph on page 405 for more)
Page 1
,Question 10: Distance from pollution source
Answer: X-axis of DO graph
Question 11: Oxygen levels
Answer: Y-axis of DO graph
Question 12: Dissolved Oxygen Graph
Answer:
Question 13: where oxygen sag starts
Answer: oxygen drops in decomposition zone, but sags in septic
Question 14: what do you think might have caused the sharp rise in BOD
Answer: the organisms in the zone needed O2 to survive
Question 15: What is the level of DO in the clean zones?
Answer: 5-10 ppm
Question 16: Water clarity is another useful measure of water quality. High clarity is an indication of
low sedimentation and __________ is measured by turbidity. This is considered __________ trophic,
Answer: low biological productivity, also considered oligo trophic
Page 2
, Question 17: Some eutrophication is normal/healthy. It brings nutrients needed for plant growth.
However, it is more often today associated with ecological collapse. Describe this process step by step,
starting with nitrates and phosphates (from either fertilizer or animal waste)
Answer: 1Chemicals/ artificial fertilisers: Chemicals and artificial fertilisers (nitrates/phospahtes) used on
the land (e.g. for farms/crops) are washed into a pond/ lake by rainwater. Algal bloom: The excess nutrients
from the chemicals cause the algae in the water to grow at a fast rate and bloom over the surface of a
pond/lake. Plants die: The algal bloom on the surface of the water blocks sunlight to the plants at the bottom
of the pond/lake. As plants require light for photosynthesis and this light is blocked, the plants die.
Decomposition of the dead plants and algae: The algae eventually die and bacteria decompose both the dead
plants and the dead algae, further using up the oxygen in the pond/lake. Fish die: As there are no longer
plants to supply oxygen to the water and bacteria are decomposing dead plants and algae further using up
the oxygen, the oxygen in the lake depletes. As there is not enough oxygen in the pond/lake to survive, the
fish suffocate and die.
Question 18: Pathogens
Answer: infectious agents that are the most serious water pollutants worldwide, they cause: roundworm,
fluke infections, e.coli, fatal diseases, cholera, polio, infectious hepatitis, etc. -in developing countries this
comes from night soil (human/animal waste) as fertilizer
Question 19: coliform bacteria
Answer: Bacteria that live in the intestines (including the colon) of humans and other animals, used as a
measure of the presence of feces in water or soil.
Question 20: Toxic metals
Answer: Mercury (most problematic, comes from consuming fish), lead, cadmium, tin, nickel
Question 21: Over 1/2
Answer: # of fish with unsafe mercury levels
Question 22: shark, swordfish, king mackerel, blue-fine tuna, marlin
Answer: fish that should be avoided due to how much mercury they likely contain
Question 23: persistent organic pollutants (POPs)
Answer: organic chemicals, often unchlorinated, used to make drugs, pesticides, DDT, all types of plastics
(dioxins) and cleaning aids, antibiotics. Many are toxic in small doses and degrade really slowly. Many of
them also bio accumulate and bio magnify in the food chain
Page 3
Question 1: Natural Sources of water pollution
Answer: oil seeps, erosion, weathering (metals), salt concentrations, radioactivity, volcanoes
Question 2: Difference between point and non-point anthropologic causes of water pollution
Answer: -point-causes are direct and traceable -non point-scattered, no specific location of discharge
-NONpoint is harder to control because it is harder to regulate and multiple causes blend together PLUS the
timing is irregular and is affected by rain/seasons
Question 3: Point sources of pollution
Answer: sewage treatment, mining, factories, power plants, tail pipes of car, leaking septic tanks
Question 4: nonpoint source pollution
Answer: lawns/gardens (fertilizers)gold, crops, feedlots/pastures, untreated sewage, roads, construction
sites, atmospheric deposition
Question 5: Atmospheric deposition
Answer: -a certain type of nonpoint pollution of contaminants carried by air currents and precipitated into
watesheds or directly onto surface waters -Like: insecticides, herbicides, NOxs
Question 6: Life at low levels
Answer: sludge worms, midge/mosquito larvae, etc
Question 7: BOD
Answer: stands for biochemical oxygen demand (demanded by the bacteria)
Question 8: Dissolved oxygen measurements indirectly measure BOD. They are often used because they
are easier, quicker, and cheaper. Still it is an indirect measurement. What other factors does DO
depend on?
Answer: -Eutrophication=low DO -Summer=Low DO -Pollution -Temperature high=Low DO -Aeration
high=DO High
Question 9: Clean Zone Macroinvertebrates
Answer: mayfly, stone fly, caddis fly larvae (see graph on page 405 for more)
Page 1
,Question 10: Distance from pollution source
Answer: X-axis of DO graph
Question 11: Oxygen levels
Answer: Y-axis of DO graph
Question 12: Dissolved Oxygen Graph
Answer:
Question 13: where oxygen sag starts
Answer: oxygen drops in decomposition zone, but sags in septic
Question 14: what do you think might have caused the sharp rise in BOD
Answer: the organisms in the zone needed O2 to survive
Question 15: What is the level of DO in the clean zones?
Answer: 5-10 ppm
Question 16: Water clarity is another useful measure of water quality. High clarity is an indication of
low sedimentation and __________ is measured by turbidity. This is considered __________ trophic,
Answer: low biological productivity, also considered oligo trophic
Page 2
, Question 17: Some eutrophication is normal/healthy. It brings nutrients needed for plant growth.
However, it is more often today associated with ecological collapse. Describe this process step by step,
starting with nitrates and phosphates (from either fertilizer or animal waste)
Answer: 1Chemicals/ artificial fertilisers: Chemicals and artificial fertilisers (nitrates/phospahtes) used on
the land (e.g. for farms/crops) are washed into a pond/ lake by rainwater. Algal bloom: The excess nutrients
from the chemicals cause the algae in the water to grow at a fast rate and bloom over the surface of a
pond/lake. Plants die: The algal bloom on the surface of the water blocks sunlight to the plants at the bottom
of the pond/lake. As plants require light for photosynthesis and this light is blocked, the plants die.
Decomposition of the dead plants and algae: The algae eventually die and bacteria decompose both the dead
plants and the dead algae, further using up the oxygen in the pond/lake. Fish die: As there are no longer
plants to supply oxygen to the water and bacteria are decomposing dead plants and algae further using up
the oxygen, the oxygen in the lake depletes. As there is not enough oxygen in the pond/lake to survive, the
fish suffocate and die.
Question 18: Pathogens
Answer: infectious agents that are the most serious water pollutants worldwide, they cause: roundworm,
fluke infections, e.coli, fatal diseases, cholera, polio, infectious hepatitis, etc. -in developing countries this
comes from night soil (human/animal waste) as fertilizer
Question 19: coliform bacteria
Answer: Bacteria that live in the intestines (including the colon) of humans and other animals, used as a
measure of the presence of feces in water or soil.
Question 20: Toxic metals
Answer: Mercury (most problematic, comes from consuming fish), lead, cadmium, tin, nickel
Question 21: Over 1/2
Answer: # of fish with unsafe mercury levels
Question 22: shark, swordfish, king mackerel, blue-fine tuna, marlin
Answer: fish that should be avoided due to how much mercury they likely contain
Question 23: persistent organic pollutants (POPs)
Answer: organic chemicals, often unchlorinated, used to make drugs, pesticides, DDT, all types of plastics
(dioxins) and cleaning aids, antibiotics. Many are toxic in small doses and degrade really slowly. Many of
them also bio accumulate and bio magnify in the food chain
Page 3
