Water Pollution Chapter 21 (pgs 338-355)

Section 21.1 Water Pollution Problem Objectives: Explain the link between water pollution and human disease. Identify the major types of water pollutants and their sources. Think Critically Medical waste on NY and NJ beaches, warnings not to eat shellfish in Delaware because of bacteria in the water, an oil slicks near Texas and Alaska discolor beaches and damage ecosystems. What is the major cause of these problems? How can these problems be stopped?

Water Pollution Problem For many years, people dumped garbage into waterways As waters became contaminated, infectious diseases (cholera, typhoid, dysentery) became more common In 1885 in Chicago, 90,000 people died from a cholera outbreak German doctor, Robert Koch, linked cholera outbreaks to contaminated water People realized contaminated water was a problem and began dumping garbage further out at sea But garbage in the ocean affects the ocean ecosystem and drifts back to shore

Sewage Sewage – water that carries organic wastes from humans and industry Comes from toilets, sinks, washing machines, and industrial equipment The U.S. dumps approx. 8.9 trillion liters of sewage into the ocean each year Most of this waste is treated, but some may not be treated and can contain toxic chemicals and metals Also, in many developing countries, sewage is not treated at all

Sewage Treatment Plants Sewage Treatment Plant – a facility that processes raw sewage before the sewage is returned to surface water systems Sewage is 1st passed through screens that filter out plastics, fabrics, and metal objects Further processing includes the treatment of solid materials called sludge, and the addition of bacteria and purifying chemicals Bacteria – break down organic pollutants Chemicals (chlorine) sanitize and deodorize These treatments do nothing to remove organic matter This organic matter can lead to an excess of nutrients in the water which causes eutrophication

Pathogens Pathogens – parasites, bacteria, and viruses that cause diseases in living things Many pathogens spend part of their lifecycle in water – they enter the water through infected raw sewage or animal wastes Pathogens carried by water result in more human illness and death than any other environmental factor With improved sanitation in developed countries diseases like cholera and typhoid are under control In developing countries – still a problem!

Schistosomiasis Disease caused by microscopic worms that enter through the skin of people who walk in water contaminated by infected human waste The worms attack the liver, bladder, and intestines Affects as many as 100 million people in the tropics and causes > 1 million deaths/year Most common in Africa, the Middle East, and Egypt

Malaria Disease caused by a protozoan Transmitted to humans by bite of infected mosquito Water serves as the breeding ground for the mosquitos Worldwide > 800 million people are infected with malaria One million people die each year Common in Africa, East Asia, and Latin America

Types of Water Pollution

Check For Understanding 1. What is sewage? 2. Create a flowchart that details the relationship between sewage, contaminated water, pathogens, and humans

Section 21.2 Chemical Pollutants Objectives: Examine the sources and effects of inorganic and organic toxic chemicals Describe the process of eutrophication and its effects on lake ecosystems Think Critically Did you ever read the book “Alice’s Adventures in Wonderland”? There was a character called the Mad Hatter. Can you guess why he was called Mad?

Toxic Chemicals Toxic chemicals – elements and molecules that are directly harmful to living things Inorganic chemicals – elements or molecules not derived from organisms Organic chemicals – molecules containing atoms of carbon that are derived from organisms

Inorganic Chemicals Include acids, salts, heavy metals, and plant nutrients Heavy metals – metallic elements with high atomic masses (lead, mercury, arsenic, chromium, etc) that are often from industrial processes Plant nutrients – molecules that do not contain carbon but are needed for plant growth (phosphates, nitrates) Enter water through seepage, runoff and direct discharge into lakes, rivers, and streams, and oceans

Minamata, Japan Animals began to behave strangely – birds fell out of trees, cats acted crazy Townspeople began to complain of headaches, dizziness, blurred vision, and numbness of hands and feet The cause of symptoms turned out to be mercury poisoning A plastics factory was discharging mercury directly into Minamata Bay This contaminated the fish, which the people ate Over 20 years, 8,000 people suffered paralysis or brain damage and several hundred people died.

Organic Chemicals Chemicals from living things or synthetically made Gasoline, oils, plastics, some pesticides, fertilizers, solvents, and wood preservatives Enter water as: Wastes from petroleum refineries, chemical factories, and from canning, meat- packing, and food processing plants Runoff from farmland Crude oil spills

Exxon Valdez 1989- oil tanker ran aground off coast of Alaska 42,000 metric tons of crude oil gushed into Prince William Sound Ecosystem was devastated and thousands of birds, mammals, and other organisms dies

Eutrophication Fertilizers and detergents contain nutrients, phosphates, and nitrates They enter the water system and promote the growth of algae and aquatic plants When plants die, get huge amounts of decomposing bacteria Bacteria use up all the oxygen and the fish die More than 65% of the lakes in the U.S. are affected

Issues – Lake Erie: A Success Story Read page 346 in your textbook Answer Decision questions on a sheet of paper and hand in before class is over.

Check For Understanding 1. What is eutrophication? 2. Describe the difference between an organic and inorganic chemical. Give one example of water pollution by each. 3. The Exxon Valdez oil spill occurred because of human error. Can the possibility of human error ever be eliminated?

Section 21.3 Radioactivity and Thermal Pollution Objectives: Explain the problems of radioactive and thermal water pollution Think Critically Nuclear power plants can produce energy that does not pollute the air. But, they also produce a lot of radioactive wastes that are hard to get rid of. Do you think we should rely on nuclear energy?

Radioactivity Radioactive elements are used as fuels in nuclear power plants, as medicines, and in nuclear weapons Radioactivity is very dangerous and radioactive wastes are difficult to handle Whether a solid or a liquid, they may result in water pollution In 1973, 1 million liters of radioactive waste leaked into the soil from the Hanford nuclear weapons site in Washington The radiation contaminated the fish and drinking water 2,100 people were exposed to dangerous levels of radiation

Thermal Pollution A large increase in water temperature due to human activity Usually occurs in lakes, rivers, or shallow bays near power plants or industrial sites Affects ecosystems in several ways: Increased water temperature decreases the amount of dissolved oxygen Increased water temperature increases the body temperature of fish, which increases their metabolism so they need more oxygen Fish suffocate because they can’t get enough oxygen Higher temperatures of water is also destructive to developing fish eggs

Check For Understanding 1. What is thermal pollution? 2. Nuclear power plants produce large amounts of radioactive water? Why?

Section 21.4 Controlling Water Pollution Objectives: Identify government attempts to control water pollution. Describe the problems involved in enforcing laws regarding water pollution. Think Critically Water pollution is found almost everywhere. Laws have been made to control this pollution. Why might these be hard to enforce?

Laws Beginning in 1898, laws were designed to control water pollution. But, the laws were not strong enough and not enforced. Individual states responsible for enforcing laws Scientific reports on pollution were not accurate Several sources could be responsible for pollution – who pats? Little was known about the effects of pollution on ecosystems The politics of industry (money or environment?) In response Congress passed the Clean Water Act (1972) which was an attempt to set water quality standards for all states

Check For Understanding 1. What is being done to control water pollution? Are these measures effective? 2. What can you do as an individual to reduce the effects of water pollution? 3. You are on the town planning community. A company that employs 75% of the people in your community has been cited for water pollution violations. The company says it will move if it is told to pay the fines. Will you vote to make the company pay?