Water Pollution

Water Pollution Problem• For many years, people dumped garbage

into waterways• Contamination caused: diseases such as cholera, typhoid,

dysentery• In 1885 in Chicago, 90,000 people died from a cholera

outbreak• Robert Koch- German doctor, linked cholera outbreaks to

contaminated water• People realized contaminated water was a problem and

began dumping garbage further out at sea• What is the problem with this??

Sewage

• Sewage – water that carriesorganic wastes from humans and industry• Where does it come 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

Sewage Treatment Plants• Sewage Treatment Plant – a facility that

processes raw sewage before the sewage is returned to surface water systems• Sewage screens that filter out plastics, fabrics, and metal

objects 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 can cause eutrophication.• Eutrophication: excess of nutrients in a lake or body of water

What do you think about this? Good or bad?

Pathogens• Pathogens – parasites, bacteria,

and viruses that cause diseases in living things• Many pathogens spend part of their

lifecycle in water they enter thewater through infected raw sewage or animal wastes cause human illness and even death• With improved sanitation in developed countries

diseases like cholera and typhoid are under control• In developing countries – still a problem!

Malaria

• Disease caused by a protozoan• Humans infected by

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

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• 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

Heavy Metals PoisonsHeavy metals are metallic elements with high atomic

masses (that’s why their called HEAVY)EX: Arsenic, lead, nickel chromium and mercury Many heavy metals find their way into ground water as

by-products of manufacturing products. EX: Plastics, paint

In 17th century France mercury was used to treat material for hat-making.

How might the hat-makers be exposed to mercury?What were the effects of mercury poisoning on the hat

makers? Emotional disturbancesLack of coordinationShyness

Organic Chemicals• Chemicals from living

things or synthetically made, contain the element CARBON• Gasoline, oils, plastics, some

pesticides, fertilizers, solvents, and wood preservatives• Enter water as:• Wastes from petroleum

refineries, chemical factories, food processing plants

• Runoff from farmland• Crude oil spills

Minamata, Japan• Animals began to behave strangely –

birds fell out of trees, cats acted crazy• Townspeople: headaches, dizziness,

blurred vision, and numbness of hands and feet• The cause of symptoms turned out to be

mercury poisoning• A plastics factory- dumped 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.

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• 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

Radioactivity

• Radioactive elements fuels in nuclear power plants, as medicines, and in nuclear weapons• Dangerous and 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

• 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

Laws• 1898 laws were designed to control water

pollution.• The laws were not strong enough and not enforced.• Little was known about the effects of pollution on

ecosystems• The politics of industry (money or environment?)

• Clean Water Act (1972): Congress passed this act which

was an attempt to set water quality standards for all states