WATER CONTAMINANTS

UNDERSTANDING EARTH SYSTEMS WATER SYSTEMS

MRSTAV

PREDICT

OBSERVE

EXPLAIN

DENSE �DEAD SEA

PREDICT

OBSERVE

EXPLAIN

FRESH WATER

SALT WATER

PREDICT

OBSERVE

EXPLAIN

IF/THEN STATEMENT

IF…

If we place one egg in fresh water and one egg in salt water,

THEN…

then ????.

PREDICT

OBSERVE

EXPLAIN

FRESH WATER

SALT WATER

PREDICT

OBSERVE

EXPLAIN

PREDICT

OBSERVE

EXPLAIN

1. Why were the results �different in each beaker?
2. How can these results help you to explain the effects of the Dead Sea?

PREDICT

OBSERVE

EXPLAIN

WATER CONTAMINANTS

UNDERSTANDING EARTH SYSTEMS WATER SYSTEMS

MRSTAV

SALINITY

• the salinity measures the concentration of the salt
• recall that concentration is calculated by dividing the mass by the volume

a measure of the amount of salt in a water sample

C =

m

v

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SALINITY

• the greater the mass of salt dissolved in a sample, the higher the salinity will be

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a measure of the amount of salt in a water sample

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ATLANTIC OCEAN

3 g of salt �in 100 mL of water

C = 3 g/mL or 3%

30 g of salt �in 100 mL of water

C = 30 g/mL or 30%

DEAD SEA

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the higher the salinity, �the denser the salt solution

people in the Dead Sea float so easily because the salinity is so high

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DESALINATION

• the salt water is heated to the point of boiling
• the water particles evaporate, leaving the salt particles behind
• the water vapour is collected and cooled, causing it to condense back into liquid water

The process to remove salt from water

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CHEMICAL CONTAMINANTS

• salt is used to in winter to prevent ice buildup but in the spring it can wash off the roads and into the waterways
• increased salinity in fresh water is a serious problem for the organisms in the aquatic system that require fresh water

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contaminants found in air and on the ground can wash into the water system

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CHEMICAL CONTAMINANTS

• fertilizers are for farming and for lawns and gardens but are often applied too liberally and the excess can’t soak into the ground, allowing some to enter the water system
• if enough fertilizer makes its way into the water system, it can cause an algal bloom

contaminants found in air and on the ground can wash into the water system

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ALGAL BLOOM

• the high levels of fertilizer feeds the algae that exists in the water system to the point that it grows uncontrollably
• the massive growth in algae:
• blocks sunlight from reaching the other organisms
• decaying algae uses up oxygen in the system

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CHEMICAL CONTAMINANTS

• HERBICIDES/PESTICIDES are used to control unwanted species but excess amounts wash into the water
• many of these substances can biomagnify within the species found in the water system

contaminants found in air and on the ground can wash into the water system

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BIOMAGNIFY

• small algae become contaminated and then are eaten by larger organisms, which also become contaminated
• the higher the contaminant moves up the food chain, the more concentrated they become within the organisms

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BIOMAGNIFY

• organisms that are higher up the food chain can have enough contaminant that serious problems can result
• e.g. DDT caused shell weakness for eagles,
• mercury levels are very high in Great Lakes fish

DDT

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BIOLOGICAL CONTAMINANTS

• MANURE from farms found in low lying areas can contaminate water when surface run-off washes parasites into the water system
• parasites such as�E. coli can be fatal while others such as Giardia cause intense nausea and diarrhea

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biological contaminants come from living sources and can also enter the water system

MRSTAV

• Salinity
• Concentration
• Desalination
• Chemical Contaminants
• Algal Bloom
• Biomagnify
• Biological Contaminants
• Dichlorodiphenyltrichloroethane

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