1
In general, what is water pollution? What is the difference between point source and nonpoint source pollution, and what are some common sources of each?
INFOGRAPHIC 15.1
Water pollution is:
found only in surface water near cities.
primarily excess nutrients from lawns, farms, and animal feedlots.
usually from excess carbon being added to the system.
contaminants or excess nutrients in surface water and in groundwater.
D
Fertilizer from your lawn and motor oil from the leaky oil pan on your car are examples of:
nonpoint source pollution.
point source pollution.
eutrophication.
pathogenesis.
A
Compare and contrast three typical point source pollutants and three nonpoint source pollutants from the area where you live.
Answers will vary, depending on whether the area is rural, suburban, or urban. Point source pollutants could be industrial or agricultural chemicals (see the Toxic Release Inventory of the EPA for specifics on a given zip code area). Non-point source pollution could include fertilizer, pesticide and sediment runoff from farms, ranches, lawns, golf-courses, construction sites, streets and parking lots, or air pollutants that fallout and enter the water.
2
What is eutrophication? How can water pollution from fertilizer or animal waste cause eutrophication and ultimately kill aquatic life?
INFOGRAPHIC 15.2
True or False: Hypoxic waters are waters with extremely low levels of oxygen.
TRUE
The following items are parts of the process of eutrophication.
Algae quickly reproduce, blocking sunlight to underwater plants.
Bacteria decompose organic matter (dead algae).
Underwater plants die.
Excess nutrients enter a body of water.
What is the correct order of these parts in the process?
4, 1, 3, 2
Many pastures have ponds to provide water to the livestock. By summer’s end these ponds are often covered in a thick green scum. If the ponds are stocked with fish, the fish can all die. What causes the green scum to form, and what might cause the fish to die?
The green scum indicates algae growth that has probably been fed by animal waste washing into the pond. The floating algae can block sunlight and reduce underwater photosynthesis decreasing underwater oxygen levels. Bacterial growth may also increase as the algae die, further depleting the oxygen - if oxygen levels fall far enough, the fish could die.
3
What is a watershed, and how does it affect the quality of surface water as well as the quantity of groundwater?
INFOGRAPHIC 15.3
A watershed includes:
only the land that would be underwater in a normal rainfall year.
the surface water and the underground aquifer.
all the uphill land surrounding a river and the streams that can feed water into that river.
all the land downhill from a river that could potentially be flooded.
C
You are investigating a die-off of fish in the local mountain lake, Lake Pleasant. It is fed by Hilltop Stream, and the Happy Valley River comes out of the lake and heads down toward Happy Valley. Do any of the following have something to do with the die-off? Justify your answers.
The new manufacturing plant just over the hill in the next valley
The cattle feedlot on the edge of the Happy Valley River
The recent construction of a new subdivision on the eastern slopes above Lake Pleasant
The lovely older neighborhood with wide lawns, a golf course, and a large grassy park on the western slope above the lake
• The manufacturing plant is not in the same watershed so it does not contaminate the lake.
• The cattle feedlot is on the river, which is at a lower elevation than the lake, so it does not impact the lake.
• The new subdivision may cause sediment and fertilizers, pesticides and herbicides to enter the lake.
• The older neighborhood adds fertilizers, pesticides, herbicides, possible household chemicals, automobile wastes, possible sewage and drug contamination of the waters.
4
Why is nutrient pollution from agricultural sites a bigger problem today than in years past?
INFOGRAPHIC 15.4
Nitrogen and phosphorus pollution in the Gulf of Mexico could originate from:
anywhere in the Mississippi River watershed.
areas 100 miles or less upstream from the Gulf.
only farms that lie in the floodplain or delta of the Mississippi River.
agricultural areas but not suburban or urban areas.
A
According to Alex Echols, what three changes to agriculture contribute to the increase of nutrient pollution to the Mississippi River? What could be done to reduce each?
1) change to crops like soybeans and corn that “leak” nitrogen back into the soil (don’t take up all the nitrogen added as fertilizer)
2) using more synthetic fertilizers which makes it possible to add enormous amounts — much more than would be added from manure or other natural sources
3) installing drainage systems to drain excess water out of soil for planting (also takes nitrogen with it. Reducing nutrient pollution could involve switching back to crops that don’t leave as much soluble nitrogen in the soil, reducing the use of synthetic fertilizers (add natural fertilizers or add any fertilizer more efficiently so that only that which is take up by plants is added at any one time) and using controlled drainage to limit the loss of water after fertilizers are added.
5
What actions can be taken to address water quality and quantity problems in the Gulf of Mexico watershed and in other areas?
INFOGRAPHICS 15.5, 15.6, AND 15.7
True or False: The Clean Water Act focuses primarily on reducing nonpoint source pollution.
FALSE
In a biological assessment of stream health, scientists collect bottom-dwelling insects and assess water quality based on:
physical parameters important to life, such as temperature and pH.
the chemical composition of insects captured.
the diversity and abundance of the species present.
the reproductive health of the insects, as determined by the number of eggs and larvae found.
C
Which of the following would be the best land use for a riparian area in terms of reducing runoff pollution?
A paved surface that is smooth and unobstructed
A well-manicured lawn
A forested area with lots of native trees and shrubs
An agricultural field such as a corn field
C
Rain gardens can be planted in areas to:
reduce the amount of stormwater runoff reaching streams.
prevent infiltration.
capture rainfall so it can be used by the homeowner.
direct runoff to storm drains.
A
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