3.2 - Changing the Concentration of Harmful Chemicals to the Environment

Question 1

What is dispersion?

Answer 1

Involves scattering a chemical over a large area to avoid causing too much damage to one spot

Question 2

What is dilution?

Answer 2

Involves mixing a chemical with large amounts of air or water to reduce its concentration

Question 3

What is biodegradation?

Answer 3

When organisms such as earthworms, fungi, and bacteria break down organic material, including some pollutants

Question 4

True or False:

Some bacteria use carbon from substances for food

Answer 4

False. All bacteria use carbon from substances for food

Question 5

WHat is aerobic biodegradation?

Answer 5

When O2 is present, some bacteria thrive. This is called aerobic biodegradation

Question 6

WHat is anaerobic biodegradation?

Answer 6

Some bacteria thrive when O2 is absent. Some anaerobic bacteria can remove chlorine from harmful compounds such as PCBs

Question 7

When would bacterial growth and biodegradation slow?

Answer 7

Bacterial growth and biodegradation slow during cold winter months

Question 8

How can biodegradation be enhanced in landfills?

Answer 8

Bioreactor technology is used to enhance biodegradation in landfill. Liquids are added to create ideal conditions for decomposition

Question 9

How does adding vegetation speed up biodegradation?

Answer 9

Adding vegetation increases the numbers of bacteria and fungi, speeding up biodegradation

Question 10

What is phytoremediation?

Answer 10

Involves growing plants that “clean” the soil. These plants absorb and accumulate harmful chemicals as they grow. They are then harvested and burned or composted
- Ex. Planting of sunflowers at Chernobyl

Question 11

What is photolysis?

Answer 11

When compounds are broken down by sunlight

 - Ex. Nitrogen oxides can breakdown in the presence of light to form ozone
 - Ex. Photodegradable plastics