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Water

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  1. Water Chapter 5

  2. Our water resources • Life on Earth would be impossible without water • Living organisms contain more water than any other substance • Renewable resource that is continuously circulated by the water cycle

  3. The Water Planet • 70 % of Earth’s surface is water • 97% of that is salt water • That means on 3% of all water on Earth is fresh water • Most is frozen in the icecaps

  4. Fresh Water Resources • A. Surface water- water above ground: lakes, pond, rivers and streams • Watershed- entire area of land that is drained by a river

  5. Fresh Water Resources • B. Rivers of Controversy • 1. Why are there conflicts over water rights? Many • people rely on river water as a water supply. • 2. Dams • -A dam is a structure built across a river it restricts the flow of water downstream • water collects behind the dam and a reservoir forms

  6. Dams • What are some advantages to damming rivers? • -in a drought there is still water source • -flood control • -source of electricity • What are some disadvantages to damming rivers? • -ecosystems destroyed • -expensive • -restricts water flow down stream

  7. Fresh Water Resources • C. Ground water • 1. Ground water is water that soaks into the ground • 2. Aquifers are...porous rock formations that hold groundwater

  8. Solutions to water shortages • 1. Desalinization • process of removing salt from sea water • Disadvantages to desalinization • EXPENSIVE • Methods of desalinization • 1) Distillation • heat is used to evaporate water from salt • as water evaporates the salt is left behind • 2) Reverse osmosis • pressure is used to push water thru a semi • permeable membrane that will not allow salt to pass

  9. Solutions to water shortages • 2. Towing water • Moving it from one place to another • Icebergs • PROBLEMS • -Icebergs are hard to tow • -they melt • -hard to transport on land

  10. Solutions to water shortages • 3. Water Conservation: • Take shorter showers • Install water saving devices: faucets, toilets, shower heads etc.

  11. Freshwater Pollution • Water pollution is when chemical, physical or biological agents get into water and it degraded the water quality and affects organisms that depend on it

  12. Kinds of Pollutants • 1. Pathogens • disease causing organisms in water • comes from human waste or untreated sewage or animal waste • 2. Organic Matter • biodegradable remains of animals and plants –include feces • these come from non point sources • 3. Organic Chemicals • pesticides, fertilizers, plastics, detergents, gas, oil and other materials made from fossil fuels • these come from non point sources • 4. Inorganic Chemicals • acids, salts, toxic metals • from point and non point sources

  13. Kinds of Pollutants (continued) • 5. Toxic Chemicals • metals like lead, mercury and cadmium • come from household chemicals or industry • 6. Physical Agents • heat or solids • 7. Radioactive Waste • waste from a nuclear power plant

  14. Types of Water Pollution • 1. Point Pollution • pollution discharged from a single source • Examples – factory or treatment plant • 2. Non-point Pollution • pollution that comes from many sources • Examples - runoff

  15. Water pollution and ecosystems • Bioaccumulation – AKA: biological magnification • it is an increase of toxics at the top of the food chain • examples: DDT and Eagles, mercury in fish • Thermal Pollution • caused when excess heat gets released into the water • Excess heat can cause fish kills because warm water hold less dissolved oxygen than cooler water so fish suffocate

  16. Water pollution and ecosystems • Eutrophication • Containing excess nutrients • Occurs from decompositions- adds nutrients to the water -plants take root and sedimentation starts • Artificial eutrophication • fertilizers or other inorganic plant nutrients get into water • the fertilizer causes water plants to grow in excess (pond scum)

  17. Cleaning up Water Pollution • 1. 1972: Clean Water Act • goal to make surface waters fit for fishing and swimming • banned pollution discharge into water • required that metals be removed from waste water • 2. 1972: Marine Protection, Research & Sanctuaries Act • gave the EPA power to control the dumping of • sewage and toxins into the ocean • 3. 1975: Safe Water Drinking Act • protects both groundwater and surface water from pollution • 4. 1980: CERCLA – superfund • makes owners, operators, and customers who use • hazardous waste responsible for their clean up

  18. Ocean Pollution • 85% of pollution in the ocean comes from activities on land – runoff or dumped • Oil spills also...contaminate ocean water • Plastic is also an ocean pollutant because...it is not biodegradable • animals eat the plastic or get tangled in it

  19. Preventing Ocean Pollution • 1) MARPOL- prevents pollution from Oil tankers • prevents plastics and oils from being discharged into the oceans • 2) Oil pollution Act of 1990 requires that all oil tankers have double hauls

  20. Who owns the oceans? • If we don’t know who owns them…who should clean them up? • The Law of the Sea Treaty: • Territorial sea 12 nautical miles from nations coastline • Exclusive economic zone: 200 nautical miles from coastline • Signed by 134 countries USA was NOT one of them