Types of pollutants

One type of water pollutant is nutrients. Nutrients from fertilizer have been major water pollutants since the 1940s. Although plants and animals need nutrients for growth, an overabundance of nutrients cause algae and other aquatic plants to grow too rapidly. Rapidly growing plants in water means a greater amount of plants that will die and decay, using up dissolved oxygen in the process. As a result, fish and other aquatic life die.

A second type of water pollutant is bacterial waste (human and animal). Lakes and beaches are often closed to swimmers and fishermen because of high counts of fecal coliform bacteria from sewage (human wastes), feedlot runoff, pet wastes, and improperly maintained septic tanks. Although fecal coliform bacteria are not harmful themselves, they usually indicate that pathogens, disease-causing organisms, are present.

A third type of water pollutant is toxic, or poisonous, chemicals. The most common sources of toxic pollution are from point pollution sources (sources of pollution that are easily pinpointed) such as industrial discharges or oil spills. Toxic pollution can also come from less identifiable, or nonpoint, pollution sources, including runoff from both urban and rural areas and fallout from the atmosphere. Point sources are the easiest to correct and can be dealt with directly. Nonpoint sources are more difficult to fix and require a lot of cooperation by every part of a community.

In the past, as we progressed as a nation, we were careless with our water. Farmers used chemicals to help crops grow and to kill insects, and later the rain and snow washed these chemicals into streams and lakes. Factories made many useful products from chemicals, such as medicine, clothes, automobile lubricants, and household goods. Water was always used in the process, and wastewater was discharged into rivers and streams. People added pollutants to water when they used it in their homes and on their lawns. They added soap, toothpaste, shampoo, bleach, detergents, fertilizers, insect spray, human wastes, paint, oil, and grease, plus many more.

Today, we are more aware of the damage that can be caused by water pollution, and many best management practices (BMPs) have been developed and are used to prevent water pollution. As we learn more about our natural systems and the impacts of our interactions on these systems, we are developing new laws, regulations, and BMPs to protect our water systems.

This activity can be done individually or in groups.

1. Pour ¼ cup (60 mL) of tap water into the first jar. This is the control; you will not add a pollutant to this jar.
2. In a second jar, mix ½ teaspoon (2–3 mL) soap or detergent and ¼ cup of tap water.
3. In a third jar, mix a solution of vinegar (1½ ounces or 45 mL) and ¼ cup of tap water.
4. In a fourth jar, mix ½ teaspoon (2–3 mL) of flea powder and ¼ cup of tap water. (The powder is similar to chemicals used to kill pests in lawns and gardens.)
5. In a fifth jar, mix ½ teaspoon (2–3 mL) food scraps and ¼ cup of tap water. (Bacteria will break down the food.) Note: Avoid using any meat scraps, because they will become very smelly.

Grades 6–8

Science
The Nature of Matter
Standard 1: The student understands that all matter has observable, measurable properties.
SC.A.1.3.1: The student identifies various ways in which substances differ (e.g., mass, volume, shape, density, texture, and reaction to temperature and light).
Processes that Shape the Earth
Standard 2: The student understands the need for protection of the natural systems on Earth.
SC.D.2.3.2: The student knows the positive and negative consequences of human action on the Earth’s systems.
How Living Things Interact with Their Environment
Standard 2: The student understands the consequences of using limited natural resources.
SC.G.2.3.2: The student knows that all biotic and abiotic factors are interrelated and that if one factor is changed or removed, it impacts the availability of other resources within the system.
SC.G.2.3.4: The student understands that humans are a part of an ecosystem and their activities may deliberately or inadvertently alter the equilibrium in ecosystems.
The Nature of Science
Standard 1: The student uses the scientific processes and habits of mind to solve problems.
SC.H.1.3.4: The student knows that accurate record keeping, openness, and replication are essential to maintaining an investigator’s credibility with other scientists and society.
SC.H.1.3.5: The student knows that a change in one or more variables may alter the outcome of an investigation.

Social Studies
People, Places, and Environments (Geography)
Standard 2: The student understands the interactions of people and the physical environment.
SS.B.2.3.6: The student understands the environmental consequences of people changing the physical environment in various world locations.
SS.B.2.3.9: The student understands how the interaction between physical and human systems affects current conditions on Earth.

Grades 9–12

Science
Processes that Shape the Earth
Standard 2: The student understands the need for protection of the natural systems on Earth.
SC.D.2.4: The student understands the interconnectedness of the systems on Earth and the quality of life.
How Living Things Interact with Their Environment
Standard 2: The student understands the consequences of using limited natural resources.
SC.G.2.4.6: The student knows the ways in which humans today are placing their environmental support systems at risk (e.g., rapid human population growth, environmental degradation, and resource depletion).
The Nature of Science
Standard 1: The student uses the scientific processes and habits of mind to solve problems.
SC.H.1.4.1: The student knows that investigations are conducted to explore new phenomena, to check on previous results, to test how well a theory predicts, and to compare different theories.
SC.H.1.4.7: The student understands the importance of a sense of responsibility, a commitment to peer review, truthful reporting of the methods and outcomes of investigations, and making the public aware of the findings.
Standard 3: The student understands that science, technology, and society are interwoven and interdependent.
SC.H.3.4.3: The student knows that scientists can bring information, insights, and analytical skills to matters of public concern and help people understand the possible causes and effects of events.

Social Studies
People, Places, and Environments (Geography)
Standard 2: The student understands the interactions of people and the physical environment.
SSB.2.4.4: The student understands the global impact of human changes in the physical environment.