Chapter 21: Water Pollution. Section 21.1 – The Water Pollution Problem. Contaminated water is a major cause of human disease . Sewage – water that contains organic wastes from humans and industry. - Comes from toilets, sinks, dishwashers, washing machines and industrial equipment.
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Contaminated water is a major cause of human disease.
Sewage – water that contains organic wastes from humans and industry.
- Comes from toilets, sinks, dishwashers, washing machines and industrial equipment.
- The U.S. dumps about 8.9 trillion L of sewage into the ocean each year.
- In the U.S., most sewage is treated.
- Sewer system – urban areas where solid and liquid waste enter an underground system of interconnected pipes.
- Rainwater from streets also enter the sewer system.
- Sewage-treatment plant – a facility that processes raw sewage before the sewage is returned to surface water systems.
Sewage is first passed through screens that filter out large debris.
Sewage then enters the grit tank where it sits undisturbed.
3. Sewage is now in the settling tank where sludge can be removed.
4. Water now enters the aeration tank where oxygen is added.
5. Water gets clarified by adding chlorine and other chemicals to sanitize and deodorize the treated water.
6. Clean water gets sent back out, sludge gets disposed of properly.
- Pathogens – parasites, bacteria, and viruses that cause diseases in living things.
- Many pathogens enter water systems through infected raw sewage or animal wastes.
Typhoid fever, cholera and dysentery are all examples of bacteria infections caused by untreated water.
- Schistosomiasis (SHIS-tuh-soh-MY-uh-sis) a disease caused my microscopic worms.
- Water infected with human waste.
- Attacks the liver, urinary bladder and intestines.
- Malaria – a disease caused by a protozoan (microscopic animal-like protists).
- Transmitted from the bite of an infected mosquito.
- Water is the breeding ground for mosquitos.
- Common in Africa, E. Asia, Latin America.
Types of water pollution
1. The largest is runoff from agriculture.
- This includes pesticides, fertilizers, nutrients, plant and animal wastes.
2. The second largest is sewage.
3. Toxic chemicals.
- Elements and compounds that are directly harmful to living things.
- Inorganic – lack carbon
- Organic – contain carbon
- These range from crude oil, solvents and metallic elements, such as lead and mercury.
5. Acids and radioactivity affect land, water and air.
6. Nontoxic substances like plastics and fishing lines harm marine animals.
- DO NOT contain carbon.
- Include acids, salts, heavy metals, and plant nutrients.
- A heavy metal is a metallic element with a high mass number.
- Mercury, lead, cadmium, nickel, chromium.
- Plant nutrients such as nitrates and phosphates.
- Metal drums filled with toxic waste get dumped into oceans and the salt water corrodes the metals.
- Heavy metals from industry such as paints and plastic productions.
- Are poisonous, can cause brain, liver and kidney damage, coma, and even death.
- Minamata Bay, Japan – heavy metal poisoning known as mercury in the 1950’s.
- First signs
- Birds fell out of trees and flew into buildings.
- Cats developed a strange walk, foamed at the mouth, meowed constantly and ran into circles until they died.
- People complained of headaches, dizziness, blurred vision and numbness in their hands and feet.
Minamata Bay, Japan
-Mercury came from a plastics factory that discharged mercury into the bay.
- Contaminated the fish and shell fish which was the primary diet of the towns people.
- Over 20 years, 8000 people suffered paralysis, brain damage and several hundred people died.
- One example of toxic chemical pollution.
- Chemicals that come from living things.
- Contain Carbon.
- Synthetic organic substances such as gasoline, oils, plastics, pesticides, fertilizers, solvents, and wood preservatives.
- Crude oil is the most common and dangerous because it is transported along waterways – threat of spills.
- The process by which lakes and ponds are changed by excess plant nutrients.
- Organic materials such as nitrates and phosphates are used to fertilize crops.
- Runoff occurs.
- Large amounts of nitrates and phosphates promote growth of algaeand aquatic plants.
- Plants die and decompose, decomposers increase which starts lowering the amount of oxygen in the water which now results in increased animal death.
- The disposal of radioactive wastes, both solid and liquid, may also result in water pollution due to the containers they are stored within.
- The best location to dispose of radioactive waste would be an area underground with a low water
- Thermal Pollution – a large increase in water temperature due to human activity.
- Usually given off by power plants from the coolant water.
- Bad for fish because warm water has less oxygen than cool water.
In 1972, Congress passed the Federal Water Pollution Act, also known as the Clean Water Act.
- It was an attempt to set water-quality standards for all 50 states.
- The Clean water Act is not a set of laws for enforcement.
- It addresses the drinking water and the interstate navigation of water use.
- There are still many problems with sewage treatment, soil erosion, land-use control, and the removal of toxic chemicals and heavy metals.
- Some states have fewer regulations on water pollution in order to attract businesses.