Pollution Ch. 12, section 2 Pg368-376
Learning Objectives • Describe types of air pollution • Identify causes of water pollution • Explain methods that can be used to prevent erosion • Air, water, and soil pollution have many causes, including hazardous waste and the burning of fossil fuels.
New Vocabulary • Pollutant • Acid precipitation • Runoff • Greenhouse effect • Ozone depletion • Erosion • Hazardous Waste
Keeping the Environment Healthy • Over 6 billion people live on Earth • Large population puts a strain on the environment • You can help to lessen the strain by becoming aware of how you use natural resources
Types of Pollution • In this section, we will be discussing 3 types of pollution: • Air Pollution • Water Pollution • Soil Pollution
Air Pollution • A pollutantis a substance that contaminates the environment • Pollutants cause hazes over large cities (smog) • Results from burning wood or fuels • Pollutants in the air include soot, smoke, ash, carbon dioxide, carbon monoxide, nitrogen oxide, and sulfur oxide • Air pollution can be caused by volcanic eruptions, dust, sand, forest fires, etc…
Acid Precipitation • Water vapor condenses on dust particles in the air to form droplets that combine to create clouds; when the droplets become large enough they fall as precipitation • Pollutants from burning fossil fuels can react with water in the atmosphere to form acid rain
Effects of Acid Rain • Acid rain washes nutrients from the soil • Leads to the death of plants and trees • Runoff from acid rain can run into lakes or ponds and destroy ecosystems • Lowers pH and kills fish and other organisms
Preventing Acid Rain • Using low sulfur fuels, such as natural gas or low-sulfur coal can reduce acid precipitation • These are less plentiful and more costly to use • Smokestacks that remove sulfur dioxide before it enters the air are also effective • Reducing automobile use and keeping cars properly tuned can help, too • Using hybrid or electric cars
Greenhouse Effect • When sunlight travels through the atmosphere some of it is reflected back to the sun but the rest is trapped by atmospheric gasses • Heat trapping feature of atmosphere is thegreenhouse effect. • Without it temperatures on Earth could possibly be too cold to support life • Atmospheric gases that trap heat are called greenhouse gases • One of the most important is CO2 • The amount of CO2 is increasing and possibly trapping more heat = global warming
Greenhouse Effect • What are the events that cause the green house effect? • Fossil fuels are burned • Level of CO2 in the atmosphere increases • More heat is trapped • Average temperatures rise
Global Warming • Data collected from 1895-1995 indicated an increase of 1°C during that period • No one is certain why or what the results may be (may be human or natural part of Earth) • Changes caused by global warming: • Changing rainfall patterns • Storms and hurricanes increase • Polar ice caps melt resulting in flooding • Tropical diseases increase (malaria)
Ozone Depletion • Ozone is about 20km above Earth’s surface • Ozone is a form of oxygen • Absorbs some UV radiation from the sun • Temporarily becomes thinner over each polar region during its spring season (ozone depletion) • Thinning is caused by certain pollutant gases called chlorofluorocarbons (CFCs) • Used in cooling systems, refrigerators, freezers
What causes Ozone Depletion? • CFC’s are used in cooling systems • CFCs leak into the atmosphere • CFCs slowly rise to the ozone layer • The chemicals react with the ozone (chemical reaction) • Ozone molecules break apart
UV Radiation & The Ozone • Because of ozone depletion the amount of UV rays that reaches Earth’s surface could be increasing • Causing a rise in the cases of skin cancer & harming other organisms • Ozone is very important (companies have decided to stop making/using CFCs) • Ozone is high in the atmosphere & protects life on Earth • If ozone gets near Earth’s surface it can be harmful • Produced when fossil fuels are burned • Pollutes air in lower atmosphere • Damages lungs & sensitive tissues of animals & plants
Indoor Air Pollution • Air pollution can occur indoors as well as outdoors • Today’s buildings are much more energy efficient (better insulation, etc…) but they may also trap harmful substances in rooms by lessening air flow • For example, paints, adhesives, carpets, glues, printers, & photocopy machines give off dangerous gases (formaldehyde) • These gases are carcinogens (can cause cancer)
Carbon Monoxide • Another type of air pollutant • Poisonous gas released when charcoal, natural gas, kerosene, or other fuels are burned • CO poisoning can cause severe illness or death • It is colorless and odorless making it difficult to detect • Alarms are used to detect the presence of CO
Radon • Naturally occurring radioactive gas • Given off by some types of rock & soil • Has no color and no odor • Seeps into basements and lower floors of buildings • Second leading cause of lung cancer in the U.S. • Radon detectors can alert of increasing levels of gas
Water Pollution • Pollutants can enter water by drifting or falling in rain • Rain can also wash land pollutants into waterways • Factories and sewage treatment plants release water into waterways • Laws require that wastewater be treated to remove pollutants before it is released • Water pollution can also occur when people dump litter or waste into rivers, lakes, oceans, etc…
Surface Water • Some water pollutants poison fish and other wildlife and can be harmful to people who may swim or drink the water • Chemical pesticides sprayed on farmland can wash into lakes and streams • Chemicals can harm the animals that fish, turtles, or frogs rely on for food • Shortages of food lead to death among water-dwelling animals • Mercury and other metals can build up in tissues of fish & be transferred to people • Algal blooms can be another pollution problem • Fertilizer contains large amounts of nitrogen • Can cause rapid growth of algae • Algae die and are decomposed by bacteria that use of oxygen
Ocean Water • Polluted water can enter oceans • Oil spills can also cause water pollution • About 4 billion kg of oil is spilled into the ocean every year • “All streams lead to the ocean.” – Finding Nemo
Groundwater • Pollution can affect water that seeps underground • Groundwater is water that collects between particles of soil and rock • Comes from precipitation and runoff that soaks into soil • Flows slowly through permeable layers of rock called aquifers • Polluted groundwater is difficult and sometimes impossible to clean
Soil Loss • The movement of soil from one place to another is called erosion. • Eroded soil that washes into a river or stream can block sunlight and slow photosynthesis • It can also harm fish, clams, and other organisms • Erosion is a natural process but humans can increase it
Soil Pollution • Not only does pollution affect air and water, soil may also become polluted. • Soil can be polluted when air pollutants drift to the ground or when water carries pollutants as it flows through soil • Tossing litter on the ground or disposing of trash in landfills may cause soil pollution, also
Solid Wastes • Most solid waste is dumped in landfills • Most landfills are designed to seal out air and water to prevent pollutants from seeping into the ground • This slows down the normal decaying process though • Paper and food do not decompose as quickly and build up year after year
Hazardous Wastes • Waste materials that are harmful to animals or humans or any living organisms are called hazardous wastes. • Include chemicals such as pesticides, oil, and petroleum-based solvents, radioactive materials used to treat disease, and nuclear weapons • Usually hazardous wastes are disposed of separately from regular trash to be treated in ways to prevent environmental production
What have you learned? • List 4 ways that air pollution can affect the environment. • Explain how an algal bloom can affect other pond organisms. • Describe possible causes and effects of ozone depletion. • How could hazardous wastes in landfills eventually affect groundwater?
