Water Pollution
The addition of any substance that has a negative effect on water or the living things that depend
on water is called water pollution. Water pollution can affect ocean water, surface water,
groundwater, and even precipitation. The substances that cause water pollution are called pollutants.
Types of pollutants include disease-causing organisms, pesticides and
fertilizers, industrial chemicals, metals, radioactive wastes, and petroleum
products. Water pollution may be caused naturally. For example, there may
be buildup of sediment caused by flooding or toxins entering in the water
from volcanic eruptions. But the primary source of water pollution is it is a
result of human activity.
After a while pollutants will build up in the bodies of living things in the
water. The food chain is affected when the big fish eat the little fish that ate the algae etc. The levels
are greater in the bigger fish. When humans regularly eat contaminated fish, the toxic chemicals also
build up in their bodies. One example of this is the accumulation of mercury in fish can cause
muscular diseases in those who eat a lot of it. Over a long time, certain pollutants can build up to
levels that can cause birth defects or illnesses such as cancer. Contaminated fish and impure drinking
water are not the only means by which pollutants can affect human health. Bathing or swimming in
polluted water can irritate the skin or cause more serious
problems.
Sources of pollution are classified, in part, on how they enter a
body of water. A point source is a specific source of pollution that
can be identified, such as a leaking pipe. A nonpoint source is a
widely spread source of pollution that can't be tied to a specific point
of origin, such as runoff from a highway. The four major sources of
water pollution are human wastes, industrial wastes, and
chemical runoff, which can be divided into agricultural chemical runoff and runoff from roads . .
Dumping human wastes into drinking water can spread disease because human wastes contain
disease-causing organisms. Water treatment usually kills bacteria. During heavy rains and floods,
sewage from sanitary sewers can pollute the drinking water. In rural areas, livestock wastes that run
off into water supplies can also be a problem. In rural areas where many use a septic system, people
must be careful where they locate septic tanks. If the tank is too near a stream or on a hill,
wastewater can leak into the stream or flow downhill into the area of a well. Animal wastes can run-off
from pastures and barnyards and pass disease causing bacteria and other kinds of pollution into
bodies of water.
Water pollution caused by industrial wastes from factories and mines is a more common problem
than sewage in most areas. Many factories use strong toxic chemicals and strong acids. Other toxic
wastes are produces as a result of manufacturing and mining. Although laws control many point
sources of chemical pollution, some factories still continue to release these toxic chemicals directly
into nearby waters. Smoke and exhaust from power plants, factories,
and vehicles release chemicals into the atmosphere. The result is
rain or other forms of precipitation that are more acidic than normal,
called acid rain. When acid rain falls on lakes and ponds, the water
can become so acidic that fish and other wildlife cannot survive. Acid
rain also harms trees and eats away at stone buildings and statues.
Heated, warm water from factories can also act as a pollutant by
changing the temperature of streams or ponds into which it is
discharged. Most living organisms can only live in a narrow range of temperatures and cannot survive
in the constantly changing waters caused by factories dumping into them.
Agricultural chemicals that can enter surface water in runoff from fields include fertilizers and
pesticides. Pesticides are chemicals intended to kill insects and other organisms that damage crops.
When pesticides are washed from fields by rain or irrigation, they can harm other organisms. Runoff
from roads is another source of pollution. Gasoline, oil, and salt in road runoff pollute rivers, lakes,
and groundwater. Solving pollution problems involves cleaning up existing
problems as well as preventing new ones. One simple solution is to keep cars
and trucks in good condition and check for oil leaks.
Many pollutants are difficult to remove but eventually some are removed
from bodies of fresh water through natural cleaning processes. Living things in
lakes, streams, and wetlands filter out and break down waste materials. Plant
roots filter larger particles from water, and certain bacteria break down toxic
chemicals in rivers and lakes. The rock and sand of an aquifer naturally filter
and purify groundwater. However, if the pollution happens faster than the
natural filtering processes, what will happen? Prevention of pollution is the best
and easier way to keep our water clean.
Ways to Prevent Water Pollution
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Never throw wastes into drains because of convenience.
Dispose of garbage in a bin, landfill or by composting.
Never wash animal waste into trenches. Scoop up the waste and place it in a plastic bag and dispose of in
a trash can or bin.
Never dispose or wash pesticides or toxic chemicals into storm drains or trenches.
Find out where to take harmful waste in your area.
Use fertilizers in small quantities and do not apply them if rain has been forecasted.
Dispose of hazardous waste like asbestos, car batteries, and sewage from septic tanks, in a sanitary
landfill. To do this you must obtain a permit from the town, state or city.
Dispose of used motor oil at recycling centers. These are usually located at an area gas station or check to
see where the nearest recycling center is located.
Name __________________________ Water Pollution
1. The addition of any substance that has a negative effect on water or the living things that depend
on water is called _________________________________.
2. Circle the letter of each sentence that is true about water pollution.
a. It can affect surface water.
c. It results from human activities.
b. It cannot affect groundwater.
d. It does not result from natural causes.
3. The substances that cause pollution are called _________________________________.
4. True or False? It is safe to bathe or swim in polluted water as long as you do not drink it.
5. What are some of the pollutants found in water?
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6. List the four major sources of water pollution.
a. ______________________________ c. ___________________________
b. ______________________________ d. ___________________________
7. What is the difference between a point source and a nonpoint source of water pollution?
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8. How can a flood cause polluted surface water?
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9. True or False? Disposing of human waste is a problem only in big cities.
10. List three types of industrial pollutants. 1. ____________________; 2.___________________;
3. _____________________
11.Circle the letter of each sentence that is true about toxic chemical wastes from industry.
a.
b.
c.
d.
Few industrial processes involve toxic chemicals.
Some toxic wastes are side effects of manufacturing and mining.
Chemical pollution from factories is now controlled by law.
Factories no longer release toxic chemicals directly into rivers and lakes.
12. Rain that is more acidic than normal is called ___________________________________ .
13. How does acid rain happen?
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14. Circle the letter of each sentence that describes an outcome of acid rain.
A. Fish die off.
B. Groundwater is polluted with oil and gasoline.
C. Stone buildings and statues are eaten away.
D. Lake water becomes acidic.
15. How could warm water act as a pollutant?
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16. True or False? Fertilizers in runoff are a point source of pollution.
17. Chemicals intended to kill insects and other organisms that damage crops are called ____________.
18. List three pollutants that are found in runoff from roads.
a. _________________________b. _________________________c.___________________
19. True or False? Road runoff is a nonpoint source of pollution.
20. Circle the letter of each sentence that describes a way that polluted fresh water is cleaned
naturally.
a.Runoff waters from farm fields dilute the pollution in rivers and lakes.
b. Plants absorb metals and chemicals from lake and pond water.
c. Bacteria eat toxic chemicals and oil spills.
d. Sand and rock layers filter groundwater as it flows down through them.
4.
21.True or False? Most pollutants are not difficult to remove.
22.True or False? It is often easier to avoid causing pollution in the first place than it is to clean it up.
23.Describe some ways that can help lessen pollution. ___________________________________
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Just curious …...
How did reading and answering this worksheet make you feel?
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