Environmental Problems 7 th Grade Science Pg. 78.

Environmental ProblemsEnvironmental Problems

77thth Grade Science Grade Science

Pg. 78Pg. 78

PollutionPollution

-unwanted change in environment.-unwanted change in environment.

-what causes it?-what causes it?

-wastes, forms of energy-wastes, forms of energy

-pollutant – anything that causes -pollutant – anything that causes pollution.pollution.

-some made by -some made by natural eventsnatural events (volcanoes).(volcanoes).

-some made by -some made by humans.humans.

GarbageGarbage – Cause of – Cause of PollutionPollution

-average American – 12kg of trash per -average American – 12kg of trash per week.week.

-goes to landfills.-goes to landfills.

-hazardous waste – can catch fire, -hazardous waste – can catch fire, corrode (eat through metal), explode, corrode (eat through metal), explode, make people sick.make people sick.

ChemicalsChemicals – Cause of – Cause of PollutionPollution

-may help people, but may harm environment.-may help people, but may harm environment.

-2 groups of harmful chemicals:-2 groups of harmful chemicals:

1. CFC’s 1. CFC’s (chlorofluorocarbons)(chlorofluorocarbons) – destroy – destroy ozone.ozone. Used in aerosols, refrigerators, Used in aerosols, refrigerators, plastics.plastics.

2. PCB’s 2. PCB’s (polychlorinated biphenyls)(polychlorinated biphenyls) – – poisonous & may cause cancer.poisonous & may cause cancer. Used in Used in appliances & paint.appliances & paint.

-now banned, but still remain in atmosphere.-now banned, but still remain in atmosphere.

Radioactive WasteRadioactive Waste – Cause of – Cause of PollutionPollution

-hazardous waste that gives off -hazardous waste that gives off radiation.radiation.

-produced by nuclear power plants.-produced by nuclear power plants.

-may take 1000’s of years to recover.-may take 1000’s of years to recover.

-Chernobyl disaster, Ukraine. 1986.-Chernobyl disaster, Ukraine. 1986.

Noise Noise – Cause of Pollution– Cause of Pollution

ResourcesResources

-Renewable – can be used over & over.-Renewable – can be used over & over.

-nearly unlimited supply.-nearly unlimited supply.

-solar, wind, geothermal energies.-solar, wind, geothermal energies.

-Nonrenewable – cannot be replaced, or -Nonrenewable – cannot be replaced, or takes thousands or millions of years to.takes thousands or millions of years to.

-fossil fuels – coal, oil.-fossil fuels – coal, oil.

Exotic or Invasive SpeciesExotic or Invasive Species

-Organism that makes a home in a new -Organism that makes a home in a new place outside native area.place outside native area.

-free from predators.-free from predators.

-become pests.-become pests.

-can take over new area.-can take over new area.

ex: zebra mussels in ex: zebra mussels in

Lake ErieLake Erie

OverpopulationOverpopulation-Too many individuals for the available -Too many individuals for the available

resources.resources.

-Figure 5, pg. 81-Figure 5, pg. 81-1800- 1 billion people on Earth.-1800- 1 billion people on Earth.-2000- over 6 billion.-2000- over 6 billion.

-Why are people living longer?-Why are people living longer?-advances in medicine, farming, -advances in medicine, farming, others?others?

-Impacts on Earth?-Impacts on Earth?

Point-Source Pollution vs. Point-Source Pollution vs. Nonpoint-source PollutionNonpoint-source Pollution

-Point-source: pollution that comes -Point-source: pollution that comes from one source.from one source.

-ex: oil spills-ex: oil spills

-Nonpoint-source: comes from many -Nonpoint-source: comes from many different sources.different sources.

-ex: runoff chemicals into lake or -ex: runoff chemicals into lake or riverriver

SolutionsSolutions

-REDUCE, REUSE, RECYCLE!!!!!-REDUCE, REUSE, RECYCLE!!!!!

-figure 11, pg. 90.-figure 11, pg. 90.

-can you think of any others?-can you think of any others?