Chapter 4Chapter 4Land, Water and Air Land, Water and Air

ResourcesResourcesSection 3Section 3

Water Pollution and SolutionsWater Pollution and Solutions

Notes 4-3Notes 4-3

Limited SupplyLimited Supply

Most water on Earth is saltyMost water on Earth is salty 97%97%

Only 3% of all water is usable (fresh)Only 3% of all water is usable (fresh) 2/3 of all fresh water is in the form of ice2/3 of all fresh water is in the form of ice Groundwater is another form of fresh Groundwater is another form of fresh

waterwater Water stored in layers of soil and rock under Water stored in layers of soil and rock under

the surface of the earththe surface of the earth

Renewing SupplyRenewing Supply

Fresh water is renewableFresh water is renewable Water cycle continuously renews fresh waterWater cycle continuously renews fresh water When water evaporates, it leaves the pollution When water evaporates, it leaves the pollution

behindbehind Water is fresh once it is in the form of water Water is fresh once it is in the form of water

vaporvapor However, water can re-pollute itself if it falls However, water can re-pollute itself if it falls

through pollutionthrough pollution Forms acid rainForms acid rain

Water ShortagesWater Shortages

Occur when people use water fast than it Occur when people use water fast than it can be renewedcan be renewed Happens often in a droughtHappens often in a drought

Can also make fresh water, for places that Can also make fresh water, for places that do not have enough rain fall to produce do not have enough rain fall to produce the water that they need, by taking salt out the water that they need, by taking salt out of sea waterof sea water

Water PollutionWater Pollution

Any change in water that has a harmful Any change in water that has a harmful effect on people or other living thingseffect on people or other living things Iron or copper: make drink and bathing Iron or copper: make drink and bathing

unpleasantunpleasant Mercury or benzene: cause sickness or deathMercury or benzene: cause sickness or death Most pollution is caused by human activitiesMost pollution is caused by human activities

SewageSewage: water and human waste washed : water and human waste washed down sinks, toilets and showersdown sinks, toilets and showers Can make people very illCan make people very ill

Water PollutionWater Pollution

Agricultural WasteAgricultural Waste: : Animals waste and farm chemicalsAnimals waste and farm chemicals Fertilizers: chemicals that provide nutrients to Fertilizers: chemicals that provide nutrients to

help crops grow betterhelp crops grow better Pesticides: chemicals that kill crop-destroying Pesticides: chemicals that kill crop-destroying

organismsorganisms These can build up to harmful concentrationsThese can build up to harmful concentrations

Water PollutionWater Pollution

Industry and MiningIndustry and Mining:: Chemical plants, paper and textile mills, and Chemical plants, paper and textile mills, and

factories use metal that can pollute.factories use metal that can pollute. Metal can harm ecosystems: people, animals, Metal can harm ecosystems: people, animals,

plants and environmentplants and environment

SedimentsSediments:: Tiny particles of rock, silt and sandTiny particles of rock, silt and sand Can be washed into areas where it covers Can be washed into areas where it covers

food, nesting sites and eggs of organismsfood, nesting sites and eggs of organisms

Water PollutionWater Pollution Oil and GasolineOil and Gasoline::

Oil spills kill fish, birds and other life in ocean Oil spills kill fish, birds and other life in ocean areasareas

Gasoline can leak out of underground tanks Gasoline can leak out of underground tanks and get into groundwater and drinking waterand get into groundwater and drinking water

HeatHeat:: Power plants sometimes put hot water used Power plants sometimes put hot water used

to cool devices back into the environment too to cool devices back into the environment too soonsoon

Causes plants and animals to dieCauses plants and animals to die Cooling towers are now used to keep this Cooling towers are now used to keep this

from happeningfrom happening

Cleaning Up the WaterCleaning Up the Water To reduce water pollution:To reduce water pollution:

1.1. Treat wastes so they are less harmfulTreat wastes so they are less harmful

2.2. Find substitutes for pollutantsFind substitutes for pollutants

Sewage TreatmentSewage Treatment Primary TreatmentPrimary Treatment: removes solid materials : removes solid materials

from wastewaterfrom wastewater Water passes through filtersWater passes through filters Solids are held in tanks and particles settle outSolids are held in tanks and particles settle out

Cleaning Up the WaterCleaning Up the Water Secondary TreatmentSecondary Treatment: bacteria break down solid : bacteria break down solid

wasteswastes Water is treated with chlorine to kill disease causing Water is treated with chlorine to kill disease causing

organismsorganisms

Arcata, CAArcata, CA Wastewater flows into ponds with algaeWastewater flows into ponds with algae

Algae breaks down sewageAlgae breaks down sewage Water moves to marshes with cattails and bulrushes to Water moves to marshes with cattails and bulrushes to

clean the waterclean the water Areas are also for habitats for fish and birdsAreas are also for habitats for fish and birds Also areas for bike riding and trails for recreation Also areas for bike riding and trails for recreation

Cleaning Up the WaterCleaning Up the Water Oil and GasolineOil and Gasoline

Oil spills Oil spills can be cleaned up with bacteriacan be cleaned up with bacteria Bacteria eat the oil and reproduce as long as there is Bacteria eat the oil and reproduce as long as there is

foodfood They die off as soon as their food disappearsThey die off as soon as their food disappears Big oil spills affect the wildlife before the bacteria can Big oil spills affect the wildlife before the bacteria can

restore the ecosystemrestore the ecosystem Gasoline spills Gasoline spills are hard to clean upare hard to clean up

Soil can be removedSoil can be removed However, if gasoline reaches the groundwater…much However, if gasoline reaches the groundwater…much

worse!worse! Water has to be pumped out and cleanedWater has to be pumped out and cleaned Then it can be put back into the groundThen it can be put back into the ground

Cleaning Up the WaterCleaning Up the Water Industrial ChemicalsIndustrial Chemicals

Industries can recycle their wastesIndustries can recycle their wastes They save money and reduce pollutionThey save money and reduce pollution

Industries can change how they produce their productIndustries can change how they produce their product Use less water or create less harmful wastesUse less water or create less harmful wastes

Farming ChemicalsFarming Chemicals Finding alternatives to pesticides and fertilizersFinding alternatives to pesticides and fertilizers DDT (dichloro-diphenyl-trichloroethane)DDT (dichloro-diphenyl-trichloroethane)

1972 DDT usage was stopped1972 DDT usage was stopped Today it is labeled as a probable human carcinogen Today it is labeled as a probable human carcinogen

Stays in an organism for a long timeStays in an organism for a long time

What can you do?What can you do? Little changes can make a big differenceLittle changes can make a big difference

Don’t pour harsh chemicals down the drainDon’t pour harsh chemicals down the drain Don’t dump them in the grassDon’t dump them in the grass

Paint thinnerPaint thinner Motor oilMotor oil Garden chemicalsGarden chemicals

Use environmentally friendly cleaning suppliesUse environmentally friendly cleaning supplies