The Importance of WaterThe Importance of Water

Pollution

Water Quality

What Can We Do?

Why is there such a fuss Why is there such a fuss about conserving water?about conserving water?

80% of the earth’s surface is covered by water!

Where is this water?Where is this water?

97.2 % is in the oceans

(* as we all know salt water is undrinkable!!!)

2.15% is locked in glaciers and icecaps

That leaves us with less than 1%; 0.65% to be exact!!

Canada has less than 1% of the world’s population, but has 22% of the world’s fresh water! Lucky us, right?!

We need water We need water

To drinkTo use for washingTo use for cookingFor industrial processes (manufacturing)To irrigate cropsFor recreationSewage treatment, waste disposal

Problem: Rivers and Lakes Problem: Rivers and Lakes contain more substances than contain more substances than everever before that make water before that make water

less desirable for drinking and less desirable for drinking and other usesother uses

How did these substances get How did these substances get into the water?into the water?

R ocks

S o il A ir P lan ts A ctiv ities from P eop le

D issolved Substances in Lakes A n im a ls

Effects Hum ans Have on W ater

W a ste D isp o sa la nd

In c in e ra ting

F a rm ing M a nu fa c tu ring R e fin ing S e wa ge

A c tiv it ie s fro m P e o p le

FarmingFarming

Herbicides and pesticides:

*they get washed into nearby lakes and other sources of water

Soil nutrients are deposited into water through erosion and poor farming practices

ManufacturingManufacturing

Manufacturing plants release harmful air pollutants called dioxins

Bodies of water absorb these dioxins from the polluted air above them!

RefiningRefining

Petroleum Products are dumped in the water from ships and refineries on shore

SewageSewage

Have you ever been to Point Pleasant Park in Halifax?

What were some of the things you saw in the water?

YUCK!!!!

NeedsNeeds

Humans

We need clean water that wecan drink safely.

• The water must be freeof living things andchemical poisons!

• It must be filtered, processed, and purified.

Animals

• Aquatic animals need dissolved oxygen for breathing

• Need a clean water environment free of pollutants

Tests scientists perform to Tests scientists perform to discover what is in waterdiscover what is in water

Dissolved OxygenDissolved Oxygen

The level of dissolved oxygen in water is a very important indicator of water quality

WHY?

Water gets oxygen from two places: From the air above the water From plants in the water (photosynthesis)

Dissolved Oxygen cont.Dissolved Oxygen cont.

5-6ppm dissolved oxygen is required for normal growth and activity

<3ppm is stressful; <2 is too low for animals and plants to survive!

AcidityAcidity

Strong acids and bases are both dangerous to have in water (they’re corrosive!)

Can test pH of water with pH paper or with a pH probe

TurbidityTurbidity

Turbidity is the measure of how cloudy water is

If the water is too cloudy, sunlight is blocked from reaching aquatic plants

ReflectionReflection

How can we conserve water as

individuals? As a city?

What changes do humans have to make

to prevent water from becoming so

polluted?