Unit C Lesson 8: How Substances Travel Through Air, Soil, and Water
Completion requirements
Unit C Lesson 8: How Substances Travel Through Air, Soil, and Water |
Learning Targets |
Big Question: How are materials transported through air, soil, and water?
It is easier to understand the impacts of pollutants once you observe the movement of substances through the environment.
It is easier to understand the impacts of pollutants once you observe the movement of substances through the environment.
At the end of this inquiry, you should be able to answer the following question:
- How do wind, soil, ocean currents, and rivers carry pollutants from one area to other areas?
Pages 237, 239, and 241 to 243 in your textbook will help you answer these questions about how substances travel through the air, soil, and water.
Introduction
Particles Travel Through the Air
The other side of the world could be closer than you think. Airborne chemicals can travel halfway around the globe and alter air quality, which affects animals, plants, as well as the weather. What are the various ways that chemicals move through air, water, and soil?
Often, the place where pollution is produced is not where the contaminants stay. Pollutants can travel great distances in the air. When pollutants are released into the air in New York City, they may travel to Nova Scotia. How exactly does this happen?
The three stages of atmospheric transport are
The other side of the world could be closer than you think. Airborne chemicals can travel halfway around the globe and alter air quality, which affects animals, plants, as well as the weather. What are the various ways that chemicals move through air, water, and soil?
Often, the place where pollution is produced is not where the contaminants stay. Pollutants can travel great distances in the air. When pollutants are released into the air in New York City, they may travel to Nova Scotia. How exactly does this happen?
The three stages of atmospheric transport are
- release
- dispersion
- deposition
Stage 1: Release
Chemicals are released as pollutants into the air from some source. They enter the air from large smoke stacks, car exhausts, volcanoes, dust storms, or even forest fires.
Stage 2: Dispersion
Pollutants in the air are scattered by the winds. The distance and direction that these particles travel is dependent on
Chemicals are released as pollutants into the air from some source. They enter the air from large smoke stacks, car exhausts, volcanoes, dust storms, or even forest fires.
Stage 2: Dispersion
Pollutants in the air are scattered by the winds. The distance and direction that these particles travel is dependent on
- the pollutant's particle size
- wind speed
- the direction of the prevailing winds
Particles of pollution in the air we breathe vary greatly in size. The smaller particles that are less dense can travel greater distances than the larger and heavier pollutants can.
Wind speed affects the distance that pollutants travel. When winds are calm or light (0 to 8 km/h), pollutants can accumulate very close to where they are released. Light to moderate winds (8 to 15 km/h) transport pollutants further downwind from the source that releases the chemicals. High wind speeds (25 km/h greater) allow pollutants to travel great distances, dispersing the pollutants to many places.
Prevailing winds blow predominantly in a single general direction over a particular point on the Earth's surface. In much of Alberta, the prevailing winds come from the northwest, so the particles are spread to the southeast.
Wind speed affects the distance that pollutants travel. When winds are calm or light (0 to 8 km/h), pollutants can accumulate very close to where they are released. Light to moderate winds (8 to 15 km/h) transport pollutants further downwind from the source that releases the chemicals. High wind speeds (25 km/h greater) allow pollutants to travel great distances, dispersing the pollutants to many places.
Prevailing winds blow predominantly in a single general direction over a particular point on the Earth's surface. In much of Alberta, the prevailing winds come from the northwest, so the particles are spread to the southeast.
Stage 3: Deposition
Eventually, the transported pollutants fall from the air. These pollutants “deposit” or settle on the soil or in the water. This process is called deposition.
The closer downwind an area is to the source of pollution, the more contaminated the area becomes.
Precipitation speeds the rate of deposition of particles. The pollutant is deposited closer to the source if it is carried to the ground by precipitation (rain or snow).
Eventually, the transported pollutants fall from the air. These pollutants “deposit” or settle on the soil or in the water. This process is called deposition.
The closer downwind an area is to the source of pollution, the more contaminated the area becomes.
Precipitation speeds the rate of deposition of particles. The pollutant is deposited closer to the source if it is carried to the ground by precipitation (rain or snow).
Figure 1 – This is a blanket of volcanic ash 25 km from the eruption.
Watch
Watch the following video carefully, it does an excellent job of explaining the many ways chemicals and pollutants can travel from place to place in the environment.
Materials Transported in Water and Soil
Water moves continually around, above, and below the Earth’s surface. This continual movement of water is referred to as the water cycle.
The water that we can see in our everyday lives is called surface water. Examples of surface water are lakes, rivers, ponds, streams, and oceans. However, in the ground below your feet, there is even more water.
Groundwater is the water in the tiny gaps in soil, rocks, and sediments under the ground. The arrows in Figure 2 indicate the tiny gaps or pores between soil particles.
Water moves continually around, above, and below the Earth’s surface. This continual movement of water is referred to as the water cycle.
The water that we can see in our everyday lives is called surface water. Examples of surface water are lakes, rivers, ponds, streams, and oceans. However, in the ground below your feet, there is even more water.
Groundwater is the water in the tiny gaps in soil, rocks, and sediments under the ground. The arrows in Figure 2 indicate the tiny gaps or pores between soil particles.
Figure 2 – The water cycle
Figure 3 – Water moves between soil particles.
Soils are composed of three types of particles: sand, silt, and clay. The size of the particles varies, with clay the smallest size and sand the largest. Tiny spaces between the particles in the ground called pores are similar to the pores
in a sponge. The connection between these pores and the movement of substances in the soil depend on the size of the particles in the soil.
Water, air, or a mixture of both water and air can be in the pores. Soil is said to be permeable if it has many interconnected pores that allow substances such as water to move through it.
Water, air, or a mixture of both water and air can be in the pores. Soil is said to be permeable if it has many interconnected pores that allow substances such as water to move through it.
The composition of a soil can affect how well water flows through the soil. Smaller-sized particles pack more closely together and slow the flow of water through the soil. (See Figure 4).
Clay particles are small and tightly packed, which produces very small pores that are not interconnected. As a result, water sits above the clay because few interconnected pores allow the water to move through.
Larger-sized particles that are more loosely packed allow water to flow through the soil more easily. (See Figure 5).
Sand particles are packed loosely so there are many interconnected pores. Therefore, water or any substance can move quickly through the spaces between the sand particles.
Clay particles are small and tightly packed, which produces very small pores that are not interconnected. As a result, water sits above the clay because few interconnected pores allow the water to move through.
Larger-sized particles that are more loosely packed allow water to flow through the soil more easily. (See Figure 5).
Sand particles are packed loosely so there are many interconnected pores. Therefore, water or any substance can move quickly through the spaces between the sand particles.
Figure 4
– Smaller soil particles, like clay, slow down or stop water movement.
Figure 5
– Large particles, like sand, allow water to move freely.
Soil Contamination
Soil can become contaminated in several ways. Examples of soil pollution or soil contamination are
Any contamination in the soil enters the surface water or ground water supplies, which can negatively affect plants, organisms that live in the soil, as well as people. When water in the form of precipitation lands on the soil, it dissolves contaminates found on or in the soil, resulting in pollution.
One of four things can happen to this contaminated water solution:
Soil can become contaminated in several ways. Examples of soil pollution or soil contamination are
- spilling soapy water when you wash your car
- dumping the contents of your root beer can
- fertilizing your lawn
- applying pesticides
- spilling gasoline (which is a type of hydrocarbon)
- dog waste
Any contamination in the soil enters the surface water or ground water supplies, which can negatively affect plants, organisms that live in the soil, as well as people. When water in the form of precipitation lands on the soil, it dissolves contaminates found on or in the soil, resulting in pollution.
One of four things can happen to this contaminated water solution:
- It can evaporate into the air.
- It can run onto the street and enter the storm drain. Most storm drains empty untreated into a body of water such as a lake or a stream.
- It can soak into the soil and be absorbed by plants, which can be toxic for the plants
- It can soak into the soil and pick up pollutants as it travels downwards through interconnected pores, forming a toxic mixture called leachate. This leachate contaminates the groundwater.
Any pollution that enters soil, air, groundwater, and surface water eventually enters our drinking water because our source of drinking water comes from surface water as well as ground water. The best way to protect our drinking water is by
preventing potentially hazardous chemicals from entering the environment.
Read the table that describes how "Some Substances that Contaminate Groundwater" on page 239 of the Science in Action 9 textbook.
Interactive
Groundwater
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To see what happens when water soaks into the Earth and through bedrock, view BrainPOP video, "Groundwater". Click here to watch Groundwater.
You will need a username and password to access the video.
- Username: 0099
- Password: students
- Click here to complete the BrainPOP quiz on Groundwater. Remember to check your answers at the end!