High School Earth Science/Pollution of the Land

Sometimes human activities lower the quality or degrade the land by putting hazardous substance in the soil and water. A well-known example of this is the story of Love Canal in New York. The story began in the 1950s, when a local chemical company put dangerous chemicals in steel drum containers. They buried the containers in Love Canal, an abandoned waterway near Niagara Falls, New York (Figure 19.8). They then covered the containers with soil and sold the land to the local school system.

Figure 19.8: Steel barrels like these were used to contain the hazardous chemicals at Love Canal. After several years, they began to leak the chemicals into the soil and groundwater, which caused many people to become sick.
Figure 19.9: A resident of Love Canal protests the hazardous waste contamination in her neighborhood.

The school system built a school on the land. The city of Niagara Falls also built more than 800 homes near Love Canal. Several years later, people who lived there began to notice bad chemical smells in their homes. Children developed burns after playing in the soil, and they were often sick. A woman living in the area, named Lois Gibbs, organized a group of citizens called the 'Love Canal Homeowners Association' to try to find out why their children kept getting sick (Figure 19.9). They discovered that their homes and school were sitting on top of the site where the dangerous chemicals had been buried. They believed that the old steel drums used to contain the dangerous chemicals were leaking and making them and their children sick. They demanded that the government take action to clean up the area and remove the chemicals.

By 1979, the United States government fully realized that the old drums were indeed leaking dangerous chemicals into the soil and water where the people lived and went to school. The government gave money to many of the people to move somewhere safer and began cleaning up the site. The work of Lois Gibbs was important in bringing the problem of hazardous chemical pollution to people's attention. After the Love Canal problem, the U. S. government created a law called the Superfund Act. This law requires companies to be responsible for hazardous chemicals that they put into the environment. It also requires them to pay the money needed to clean up polluted sites, which can often be hundreds of millions of dollars. As a result, companies today are more careful about how they deal with hazardous substances.

This lesson describes some of the sources of hazardous wastes throughout the world. It then discusses the effects these wastes have on human health and the environment. Finally, this lesson covers ways that we can control hazardous wastes.

Lesson ObjectivesEdit

  • Define hazardous waste and describe its sources.
  • Describe some of the impacts of hazardous waste on human health and on the environment.
  • Detail some ways that we can control hazardous wastes.

What is Hazardous Waste?Edit

Hazardous waste is any waste material that is dangerous to human health or that degrades the environment. Hazardous waste materials include substances that are:

  1. Toxic: something that causes serious harm, death or is poisonous.
  2. Chemically active: something that causes dangerous or unwanted chemical reactions, like dangerous explosions.
  3. Corrosive: something that destroys other things by chemical reactions.
  4. Flammable: something that easily catches fire and may send dangerous smoke into the air.

Hazardous waste may be solid or liquid. It comes from many sources, and you may be surprised to learn that you probably have some sources of hazardous waste right in your own home. Several cleaning and gardening chemicals are hazardous if not used properly. These include chemicals like drain cleaners and pesticides that are toxic to humans and many other creatures. When we use, store, and dispose of them, we have to be careful. We have to protect our bodies from exposure to them and make sure they do not enter the environment (Figure 19.10). If they are thrown away or disposed of improperly, they become hazardous to the environment. Others sources of hazardous waste are shown in Table 19.2.

Figure 19.10: This farm worker wears special clothes for protection from the hazardous pesticide in the container.
Table 19.2: Sources of Hazardous Waste
Type of Hazardous Waste Example Why it is Hazardous
Chemicals from the automobile industry Fuel, used motor oil, battery acid, brake fluid Toxic to humans and other organisms; often chemically active; often flammable
Batteries Car batteries, household batteries Contain toxic chemicals; are often corrosive
Medical wastes Surgical gloves, wastes contaminated with body fluids such as blood, x-ray equipment Toxic to humans and other organisms; may be chemically active
Paints Paints, paint thinners, paint strippers, wood stains Toxic; flammable
Dry cleaning chemicals Many various chemicals Toxic; many cause cancer in humans
Agricultural chemicals Pesticides, herbicides, fertilizers Toxic to humans; can harm other organisms; pollute soils and water

Impacts of Hazardous WasteEdit

Many hazardous waste materials have serious impacts on human health. They often cause cancer and can also cause birth defects. They can make people sick for very long times. Breathing the air or drinking the water that is contaminated with hazardous waste is a major health threat.

Two chemicals that are especially toxic in the environment are lead and mercury. Lead harms people by damaging their brain and nervous system. Lead is especially harmful in children under the age of six; about 200 children die every year from lead poisoning. Lead was once a common ingredient in fuel and paint (Figure 19.11). In the 1970s and 1980s, the United States government passed laws completely banning lead in fuel and paint. This has prevented the lead poisoning of millions of children in the United States. However, several other countries still use fuel with lead in it. Also, homes built before the 1970s may contain paint that has lead in it. These still pose a threat to human health.

Figure 19.11: In the United States, automotive fuel must now be unleaded, or free from lead.
Figure 19.12: This graph shows historic increases of mercury in the atmosphere. Events in blue are volcanic eruptions. Events in brown, purple, and pink are human-caused. Notice the effect of industrialization on mercury levels in the atmosphere (the red region of the graph).

Mercury is a pollutant affecting the whole world (Figure 19.12). Mercury enters the environment from volcanic eruptions, burning coal and from waste products like old batteries and electronic switches. It is also found in old discarded electronic appliances like television sets. Like lead, mercury also damages the brain and impairs nervous system function. Mercury often accumulates in fish, so people and other animals that eat the fish then are in danger of getting the mercury in their own bodies.

Preventing Hazardous Waste PollutionEdit

The United States is currently the world's largest producer of hazardous wastes. However, as China becomes more industrialized, it may take over the number one spot. Countries with more industry produce more hazardous waste than those with little industry. Hazardous wastes can enter the air when we burn things like batteries containing mercury or old tires. Hazardous waste can enter the water when chemicals are dumped on the ground, or are buried and then leak. Substances buried in the ground often leak from their containers after a number of years. The chemicals then move through the soil until they reach groundwater. Hazardous chemicals are especially dangerous once they reach our groundwater resources. Sites like the one at Love Canal are now referred to as Superfund sites. They are found throughout the country. Many of them have been identified and cleaned up. We now have strict laws to prevent new sites like the Love Canal site from ever forming in the first place.

In the United States, we have several laws that help control hazardous waste. The Resource Conservation and Recovery Act requires any company that produces hazardous materials to keep careful track of what happens to it. The government has passed special rules for how these materials can be disposed of. Companies must ensure that hazardous waste is not allowed to enter the environment in dangerous amounts. They have to protect their workers from the hazards of the materials. They must keep a record of how they dispose of hazardous wastes, and show the government that they did so in a safe way.

Individual people can also do much to control hazardous wastes. We can choose to use materials that are not hazardous in the first place. We can make sure that we dispose of materials properly. We can control the amount of pesticides that we use. We can make sure to not pour toxic chemicals over the land, or down the drain or toilet, or even into the trashcan. We can also use hazardous materials less often. We can find safer alternatives for many of the chemicals we use. For example, we can use vinegar and water to clean windows instead of the usual glass-cleaning chemicals.

Lesson SummaryEdit

  • Hazardous wastes are dangerous to human health and the environment. They come from many sources, such as household chemicals, gasoline, paints, old batteries, discarded appliances, and industrial chemicals.
  • Once in the air or buried on land, they can cause human health problems or even death and degrade the environment for other organisms.
  • Developed countries like the United States produce most of the world's hazardous waste.
  • We have passed laws that require careful disposal of hazardous materials and that make their producers financially responsible for them if they pollute the environment.

Review QuestionsEdit

  1. How does the United States Superfund Act help control hazardous wastes?
  2. What is the difference between corrosive and flammable?
  3. Organic farming is a method of growing food crops with natural alternatives to chemical pesticides. How does organic farming help control hazardous wastes?
  4. What is one disadvantage of storing hazardous wastes in barrels buried deep in the ground?
  5. Scientists who work with hazardous wastes often wear special clothing like gloves and masks. Why do you think they wear these items?
  6. Which do you think is easiest and hardest to keep track of: hazardous waste that is present as a gas, liquid, or solid? Why?


To lower the quality of something.
Chemicals used to kill or harm unwanted pests such as insects that damage food crops.
Superfund Act
A law passed by the US Congress in 1980 that held companies responsible for any hazardous chemicals that they might create.
Superfund site
A site where hazardous waste has been spilled. Under the Superfund Act, the company that created the hazardous waste is responsible for cleaning up the waste.

Points to ConsiderEdit

  • What are the best ways to either prevent or safely dispose of hazardous materials?
  • If humans are the ones who mostly create hazardous materials, whose responsibility is it to clean them up?
  • Is it important for each generation to leave the world a safe place? If one generation doesn't do this, who pays the price?

Loss of Soils · Human Actions and Earth's Resources