Unit 7-1 Notes Mr. Hefti – Pulaski Biology. Ozone Depletion ► Ozone Depletion ► What is it? Thinning of ozone layer Shield of gases 20-50 km above Earth’s.

Ozone Depletion & Water Pollution

Unit 7-1 NotesMr. Hefti – Pulaski Biology

Ozone Depletion ► What is it?

• Thinning of ozone layer• Shield of gases 20-50 km

above Earth’s surface that absorb UV radiation from sunlight

OD ► What causes it?

• CFCs (chlorofluorocarbons) break apart ozone molecules

• CFCs were formerly used to make: – Foam– Coolants– Propellants for aerosol cans

OD ► Why is it bad?

• UV exposure causes:– Sunburns– Skin cancer– Damage to eyes– Disrupted growth patterns of producers in food

webs– Genetic mutations

OD ► What can be done about it?

• Ban CFCs [worldwide]

Water Pollution ► What is it?

• Contamination to:– Streams– Lakes– Underground water (aquifers)– Bays– Oceans

• All organisms require water

WP ► What causes it?

• Major water pollutant categories:– Chemical– Biological– Physical materials– Thermal

WP ► Why is it bad?

• Survival impossible in presence of toxic chemicals or harmful microorganisms

• Polluted water causes people to become ill or develop defects

WP ► What can be done about it?

• Clean Water Act (1972) – outstanding legislation• Sewage treatment• Discourage careless dumping through fines• Limit erosion