Water Pollution
Answer Key
Vocabulary: bacterial pollution, nutrient pollution, sediment pollution, toxic pollution, water pollution
Prior Knowledge Questions (Do these BEFORE using the Gizmo.) [Note: The purpose of these questions is to activate prior knowledge and get students thinking. Students are not expected to know the answers to the Prior Knowledge Questions.] 1. Water pollution is the addition of harmful substances to water. Some of these substances are found at home. What household chemicals might be harmful if not disposed of properly? Answers will vary. [Examples could include paint, paint thinner, weed killer, insecticide, batteries, and motor oil.]
2. What are some other causes of water pollution? Answers will vary. Gizmo Warm-up The Water Pollution Gizmo™ will teach you about some of the main kinds of water pollution. On the TYPE tab, under Types of pollution, check that Toxic is selected. Read the paragraphs on the right and bottom of the Gizmo. 1. What is toxic pollution? Toxic pollution is contamination of water by materials that cause death, disease, or birth defects.
2. What are some examples of toxic pollutants listed in the Gizmo? Paints, gas, battery acid, mercury, pesticides
3. Can you think of other examples of toxic substances, not listed in the Gizmo? Answers will vary. [There are many toxic substances. These include industrial chemicals, radioactive nuclear waste, heavy metals, PCBs, etc.]
Activity A: Types of water pollution
Get the Gizmo ready: Check that the TYPE tab and Toxic pollution are selected.
Question: What are the main types of water pollution? 1. Read and learn: Besides toxic pollution, the other types of pollution are sediment pollution, nutrient pollution, and bacterial pollution. You have already described toxic pollution on the previous page. Read about the other types, and describe each in your own words.
Sediment pollution Description:
Pollution by sand, soil, and other minerals that are washed into streams and rivers after rainfall.
Causes:
Caused by careless farming, mining, and building activities
Consequences:
Destruction of fish and wildlife habitat, clouds water (blocking sunlight needed by aquatic plants), and piles up in reservoirs, rivers, and harbors.
Nutrient pollution Description:
Contamination of water by excessive nutrients, usually nitrogen and phosphorus.
Causes:
Fertilizer, manure, and human waste
Consequences:
Excessive algae reduce sunlight passing through water. [Algal blooms can also deplete oxygen levels, killing fish and other organisms.]
Bacterial pollution Description:
Contamination of water by bacteria.
Causes:
Manure, human waste, and spoiled food.
Consequences:
Human, animal, and plant health problems. [Some types of bacteria aid in pollution control by breaking down organic matter.]
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Get the Gizmo ready:
Activity B:
Select the EXAMPLE tab. Check that example 1/12 is selected. (If not, use the arrow buttons to get to example 1/12.)
Real-world examples
Question: What are the real-world causes of water pollution? 1. Practice: For each Real-world example presented in the Gizmo, guess which type or types of pollution will result by checking the boxes. When you are ready, click Check answer to see if you were right. Read the explanation, and then use your own words to fill in the table. Example
Pollution type(s)
Explanation
1
Nutrient Bacterial
Chicken manure contains high levels of bacteria and nitrogen.
2
Toxic Nutrient
Car gases and leaking fluids cause toxic pollution. Nitrogen oxide in exhaust causes nutrient problems.
3
Toxic
Pesticides can enter the water supply through runoff or seepage through the soil.
4
Sediment
After trees are removed, exposed soil will erode into streams and rivers.
5
Toxic
Oil and antifreeze are toxic chemicals that will wash into local waterways after being dumped in the alleyway.
6
Sediment
Removal of trees and shrubs will expose soil that can be washed into the lake.
7
Toxic
Paint and paint thinner are toxic substances that will leach into groundwater at the landfill.
8
Nutrient Bacterial
The sewage treatment plant will not be able to treat all the water, so some untreated water will be released into the environment.
9
Sediment
Paper products are made from trees. Logging exposes soil and leads to sediment pollution.
10
Toxic Sediment
Oil and other fluids will wash off the parking lot into the stream. Construction will cause soil erosion.
11
Nutrient
Plants can’t use all of the fertilizer. Excess fertilizer will be washed into the environment, causing nutrient pollution.
12
Nutrient Bacterial
Human waste is leaking from the septic tank. This is a source of nutrients and bacteria.
(Activity B continued on next page)
Activity B (continued from previous page) 2. Practice: Classify each of the following examples as toxic, sediment, nutrient, and/or bacterial pollution. Explain your classifications. A. Logging removes trees from a hill, leaving a barren landscape. Classification: Sediment pollution Explanation: Without tree roots to hold it in place, soil will be washed into streams and rivers.
B. A man washes clothes in a stream using a detergent that contains phosphorus. Classification: Nutrient pollution Explanation: Phosphorus is a nutrient that can cause harmful algal blooms.
C. At an old gas station, gasoline leaks from an underground storage tank. Classification: Toxic pollution Explanation: Gasoline is a harmful chemical.
D. At a research lab, a scientist carelessly pours cultures of living microbes down the drain. Classification: Bacterial pollution Explanation: Living microbes can cause disease or infection.
3. Think and discuss: Many sources of water pollution are found within the home. What actions can you take to reduce water pollution? Answers will vary. Sample answer: To reduce water pollution, I can properly dispose of harmful chemicals such as paint, paint thinner, oil, pesticides, and cleaning solvents. (Most landfills have a special facility for handling chemicals.) I should not use excessive amounts of fertilizer on my lawn and garden. I should check below the car to make sure it is not leaking oil or antifreeze.
