water pollution

thermal pollution

Thermal pollution is pollution that raises the temperature of water. This is caused by power plants and factories that use the water to cool their machines. The plants pump cold water from a lake or coastal area through giant cooling towers, like those in Figure 21.14. As it flows through the towers, the cold water absorbs heat. This warmed water is returned to the lake or sea. Thermal pollution can kill fish and other water life. Its not just the warm temperature that kills them. Warm water cant hold as much oxygen as cool water. If the water gets too warm, there may not be enough oxygen for living things.

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coastal pollution

The oceans are most polluted along coasts. Why do you think thats the case? Of course, its because most pollution enters the oceans from the land. Runoff and rivers carry the majority of pollution into the ocean. Many cities dump their wastewater directly into coastal waters. In some parts of the world, raw sewage and trash may be thrown into the water (see Figure 21.12). Coastal water may become so polluted that people get sick if they swim in it or eat seafood from it. The polluted water may also kill fish and other ocean life.

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oil spills

Oil spills are another source of ocean pollution. To get at oil buried beneath the seafloor, oil rigs are built in the oceans. These rigs pump oil from beneath the ocean floor. Huge ocean tankers carry oil around the world. If something goes wrong with a rig on a tanker, millions of barrels of oil may end up in the water. The oil may coat and kill ocean animals. Some of the oil will wash ashore. This oil may destroy coastal wetlands and ruin beaches. Figure 21.13 shows an oil spill on a beach. The oil washed ashore after a deadly oil rig explosion in the Gulf of Mexico in 2010.

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water pollution from agriculture

Huge amounts of chemicals, such as fertilizers and pesticides, are applied to farm fields (see Figure 21.10). Some of the chemicals are picked up by rainwater. Runoff then carries the chemicals to nearby rivers or lakes. Dissolved fertilizer causes too much growth of water plants and algae. This can lead to dead zones where nothing can live in lakes and at the mouths of rivers. Some of the chemicals can infiltrate into groundwater. The contaminated water comes up in water wells. If people drink the polluted water, they may get sick. Waste from livestock can also pollute water. The waste contains bacteria and other organisms that cause disease. In fact, more than 40 human diseases can be caused by water polluted with animal waste. Many farms in the U.S. have thousands of animals. These farms produce millions of gallons of waste. The waste is stored in huge lagoons, like the one in Figure 21.11. Unfortunately, many leaks from these lagoons have occurred. Two examples are described below. In North Carolina, 25 million gallons of hog manure spilled into a nearby river. The contaminated water killed

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water pollution from industry

Factories and power plants may pollute water with harmful substances. Many industries produce toxic chemicals. Some of the worst are arsenic, lead, and mercury. Nuclear power plants produce radioactive chemicals. They cause cancer and other serious health problems. Oil tanks and pipelines can leak. Leaks may not be noticed until a lot of oil has soaked into the ground. The oil may pollute groundwater so it is no longer fit to drink.

municipal water pollution

Municipal refers to the community. Households and businesses in a community are also responsible for polluting the water supply. For example: People apply chemicals to their lawns. The chemicals may be picked up by rainwater. The contaminated runoff enters storm sewers and ends up in nearby rivers or lakes. Underground septic tanks can develop leaks. This lets household sewage seep into groundwater. Municipal sewage treatment plants dump treated wastewater into rivers or lakes. Sometimes the wastewater is not treated enough and contains bacteria or toxic chemicals.

ocean water pollution

The oceans are vast. You might think they are too big to be harmed by pollution. But thats not the case. Ocean water is becoming seriously polluted.

point and nonpoint source pollution

Pollution that enters water at just one point is called point source pollution. For example, chemicals from a factory might empty into a stream through a pipe or set of pipes (see Figure 21.9). Pollution that enters in many places is called non-point source pollution. This means that the pollution is from multiple sources. With non-point source pollution, runoff may carry the pollution into a body of water. Which type of pollution do you think is harder to control?

sources of water pollution

There are three main sources of water pollution: 1. Agriculture. 2. Industry. 3. Municipal, or community, sources.

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instructional diagrams

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questions

The Gulf of Mexico oil spill began with

a. a ship running aground

b. a rig that cracked apart in a storm

-->  c. a rig explosion

d. an onshore pipeline breaking apart

Industrial pollutants include

a. radioactive substances

b. chemicals

c. heat

-->  d. all of these

Dead zones are found mostly

a. off of industrialized areas in developed nations

b. in the Gulf of Mexico

-->  c. off of farming areas in developing nations

d. none of these

The temperature of a lake may rise if the water is

a. released from a reservoir

-->  b. used to cool a power plant

c. exposed to oil drilling

d. all of these

An example of point source pollution is

-->  a. a nuclear power plant

b. acid rain

c. a set of enormous animal farms

d. steel factories along a river

Point source pollution is harder to control.

a. true

-->  b. false

Agricultural pollution can contaminate well water.

-->  a. true

b. false

Livestock waste is always stored safely in lagoons.

a. true

-->  b. false

Industrial water pollution commonly includes toxic chemicals such as mercury.

-->  a. true

b. false

No harm is done if lawn chemicals are washed into storm sewers.

a. true

-->  b. false

Water pollution contributes to water shortages.

-->  a. true

b. false

Most ocean pollution comes from ships at sea.

a. true

-->  b. false

Most of the pollution in the oceans is carried there by rivers and runoff.

-->  a. true

b. false

Animal waste and fertilizers bring nutrients to nearby water sources.

-->  a. true

b. false

Oil leaks and spills occur only in the oceans.

a. true

-->  b. false

Thermal pollution kills fish by making the water too cold.

a. true

-->  b. false

Water pollution includes any contaminant that gets into lakes, streams, and oceans.

-->  a. true

b. false

Factory farms with thousands of animals pollute ocean water with animal wastes.

-->  a. true

b. false

In some places, people dump trash and raw sewage into the ocean.

-->  a. true

b. false

If polluted water infiltrates the ground, it is no longer a problem.

a. true

-->  b. false

major cause of water pollution

a. non-point source pollution

b. dead zone

c. point source pollution

-->  d. agriculture

e. coast

f. thermal pollution

pollution that enters water in many places

-->  a. non-point source pollution

b. dead zone

c. point source pollution

d. agriculture

e. coast

f. thermal pollution

pollution that raises the temperature of water

a. non-point source pollution

b. dead zone

c. point source pollution

d. agriculture

e. coast

-->  f. thermal pollution

where ocean pollution is worst

a. non-point source pollution

b. dead zone

c. point source pollution

d. agriculture

-->  e. coast

f. thermal pollution

pollution that enters water in just one place

a. non-point source pollution

b. dead zone

-->  c. point source pollution

d. agriculture

e. coast

f. thermal pollution

area in a body of water where nothing can live

a. non-point source pollution

-->  b. dead zone

c. point source pollution

d. agriculture

e. coast

f. thermal pollution

Sources of water pollution include

a. industry.

b. agriculture.

c. municipal sources.

-->  d. all of the above

Examples of non-point source pollution include

a. a factory discharging chemicals into a lake through a pipe.

-->  b. runoff carrying pesticides into a lake from surrounding farmland.

c. a nuclear power plant pumping warm water into a nearby lake.

d. two of the above

If dissolved fertilizer enters bodies of water, it can lead to

a. too many fish.

b. too many algae.

c. dead zones.

-->  d. two of the above

Bacteria are most likely to contaminate water if it is polluted by a(n)

a. oil refinery.

b. chemical plant.

c. nuclear power plant.

-->  d. sewage treatment plant.

Nuclear power plants use water for

-->  a. cooling.

b. chemical reactions.

c. nuclear fusion reactions.

d. neutralizing radioactive elements.

Water pollution is a problem

a. only in poor nations.

b. mainly in rich nations.

-->  c. all over the world.

d. only for ocean animals.

diagram questions

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