Water & Water Pollution Chapters 20-21

Household Water Use

Household Water Use Activity Daily Consumption Brushing teeth 19-39 L Washing hands/face 4-8 L Showering 75-80 L Taking a bath 96-116 L Dishwasher 56-60 L Toilet flushing 16-21 L (per flush)

Use the table on the previous slide & calculate your average daily water consumption

Household Water Use Average person uses 300 L daily Small percentage is for drinking and cooking

Industrial Water Use 44% of all fresh water is used by industry Power source Coolant Disposes waste 15,000 L used to produce steel for 1 washing machine

Agricultural Water Use Single largest consumer of water in US (47%) Irrigation Flood irrigation (flooding flat land) Furrow irrigation (water into ditches near crops) Overhead irrigation (sprinklers)

Types of Irrigation

Effects of Water Use on Ecosystems Dams, draining swamps, changing stream courses Damages habitat

Las Vegas

Las Vegas Water from Lake Mead Created by Hoover Dam Slowly depleting

Lake Mono, CA Mineral-rich water from surrounding mountains As water evaporates, it leaves the minerals behind 1940 they started diverting this water to other areas Increased salt concentration Affects algae & shrimp, which feeds gulls & other migratory birds

Water Sources

Surface Water Streams Lakes Ponds Melting snow Rain Melting ice caps Colorado River

Aquifers Water that has seeped down into the spaces between soil particles and eventually into the bedrock to become groundwater Top of the saturated layer of rocks is the water table Wells are used to access the aquifer

Aquifers

Overdraft Water gets used faster than it is replenished Salt water can get into an aquifer & make the water unpotable Bedrock that stores the water can weaken Land may sink or “subside”

Water Treatment

Removing Salts Desalination Can be used for drinking, cooking, and irrigation

Distilling Heat water to boiling Water vapor is collected & cooled Liquid fresh water is collected

Reverse Osmosis Salt water gets forced through a strainer that traps the salt and only lets fresh water pass The pores in the membrane are too small for salt to pass through

Freezing Salt water gets frozen It separates into ice and salty slush The ice can be melted for fresh water

Water Purification Removes harmful chemicals & microorganisms Makes water potable Sedimentation Filtration Aeration Sterilization

Sedimentation & FIltration Coagulation- chemicals added to water to make sediments clump together Sedimentation- particles settle to the bottom Filtration- sent through a fine filter

Aeration & Sterilization Water may still contain dissolved gases or bacteria that cannot be filtered out Aeration- exposing it to air by spraying it into the air, where it mixes with “good” bacteria that break the bad stuff down Sterilization- the added “good” bacteria are killed through extreme heat or very small concentrations of chlorine/ozone

Water Pollution

History of Water Pollution 19th century people would dump garbage into the most convenient waterway In London, the smell of the River Thames was so bad, that Parliament had to close on several occasions!

History of Water Pollution This build up of bacteria and pollution led to the spread of several dangerous diseases: Cholera Typhoid fever (killed 90,000 in Chicago in 1885) dysentary

History of Water Pollution Ocean dumping is still a common practice today!

Top 2 Sources of Water Pollution 1st: Runoff from Agriculture 2nd: Sewage

It goes untreated before dumping in many developing countries. Sewage Contains organic waste from humans and industry Toilets Sinks Washing machines It goes untreated before dumping in many developing countries.

Sewage The US dumps approximately 8.9 trillion Liters of sewage into the ocean every year

Sewage-Treatment Plant Processes raw sewage before it is dumped Solid waste = Sludge

Pathogens Disease-causing organisms Pathogens carried by water result in more human illness and death than any other environmental factor

Schistosomiasis Microscopic worms Enter through skin Attack liver, bladder & intestines Africa, Middle East, Egypt

Malaria Passed through bite of infected mosquito Not directly through water Attack liver Dirty Water = breeding ground for bugs

Types of Pollutants

Chemical Pollutants Toxic chemicals Directly harmful to living things

Inorganic Chemicals Usually by-products of metal treatment and plastic production Acids Salts Heavy metals (high mass number) Mercury Lead

Mad Hatters Disease Mercury from the softening of materials used to make hats Tremors Hallucinations Anxiety Insanity 2:05

Mercury Poisoning Usually from plastics factories Runoff gets into waterways & fish absorb it Early signs: local animals behaving strangely Brain damage, paralysis, liver, kidney damage

Mercury Poisoning Fish w/ high levels of mercury: Shark Swordfish Largemouth bass Tuna Mahi mahi

Organic Chemicals Gasoline Oils Plastics Pesticides & fertilizers

Eutrophication Lakes and ponds can be changed by excess plant nutrients From fertilizers and other organic wastes Overgrowth of algae & decomposing bacteria Lowers the available oxygen in the water Fish numbers decline

Eutrophication