Walk-In
• Copy the question and answer in
sentences.
• Plants produce oxygen, and also
use oxygen to grow. Would a large
amount of dissolved oxygen in
water be good or bad for plants?
Walk In
• Copy this week’s agenda
down quietly.
Testing Water Quality
What can affect our water quality?
• Watch this trailer for the
documentary, Gasland, about
the effect of human activities
on our water!
What else affects
our water?
• Quickly discuss these questions
at your table…
– Where does our drinking water come from?
– When you flush the toilet, does that water end up in a
home’s tap water?
– How do we know that the water in the tap is safe?
– If water is contaminated, can it be cleaned?
4 Ways Humans Impact Water
#1. In your notebook, write 4 ways you think
humans can impact (have an effect on)
water quality.
Human activities do impact
water sources.
Did you write some of these?
– Golf course (fertilizers)
– Water parks (human waste)
– Home (sewage)
– Car washing
– Rain water in cities (gutters on the roads)
– Garbage dumps / landfills
– Paint, pesticides, litter, chemical fertlizers
– Corrosion from plumbing
Water Will have Contaminants
• Contaminants will have to be removed or
treated
• Some will be visible to the naked eye:
– Sediment (sand, gravel, small stones)
– Large particles like tree branches, twigs, animal
carcass
– Smaller particles leaves, grass, animal waste
– Particles not visible: dissolved in the water
#2. Write three examples of contaminants large
enough to be seen by the naked eye.
Testing Water Quality
You will test different sources of water for
contaminants.
• These are the substances you
are testing for:
–pH (if acid or alkaline)
–Nitrate
–Phosphate
–Dissolved Oxygen, D.O.
Read: Contaminants and their Effects
Contaminant
pH (acidity vs
alkalinity)*
Nitrate*
nitrogen
Phosphate*
phosphorous
Source
Effect
on health
Acid (low pH)
Low pH: Sour
Alkalinity, limestone taste
(high pH)
High pH: Bitter
metallic taste
Runoff from
Infants (< 6 mo.)
fertilizer
May become
seriously ill/ die
Sewage; Runoff
Severe exposure:
from agriculture
kidney weakened
sites; lawn fertilizers
Read: Contaminants and their Effects
Contaminant
Dissolved
oxygen DO
Source
Effect
on health
The sources of
dissolved oxygen (D.O.)
in natural waters is
from atmosphere and
photosynthesis of
plants.
When a body of water is
over productive, the oxygen
in the water may get used
up faster than it can be
replenished. This occurs
when a body of water is
overstocked with organisms
or if there is a large algal
bloom die-off.
Walk-In
• Take out engineering notebook and pencil.
• Put backpack near the wall.
• Read the instruction
cards in the middle of the
table.
• Write a summary in your notebook of
the general procedure to test the water.
Test water samples
• You will test water samples for:
– pH
– Nitrate
– Phosphate
– Dissolved Oxygen
• We will have multiple samples:
– Bottled water
– Tap water
– Lake water (from the lake in Lakewood)
– Stream water (from a stream in Chandler)
Materials
PER TABLE
- 1 tablet each for testing nitrate, phosphate,
DO, and pH.
– 1 “Results card”.
– 2 plastic test tubes with caps
–A/B will test nitrate and
phosphate
–C/D will test DO and pH.
Recording Your Information
• Recording chart
• Locate the column for your group’s type of
water.
• Write your results in the your chart.
• Later, we will share class results and find
the average value.
Doc-Cam Class Chart
• You will also enter your group’s results into
the class chart under the doc-cam, so
groups can share information.
Get Acquainted With The Materials
• Look at the set-up on the demo table.
• Get a test-tube, small tube, results card.
• Pick up the GRAY INSTRUCTION CARDS
for each kind of tablet and read them.
• Safety: We will wear goggles during the
lab.
Background Information
• For each slide about contaminants that
follows,
– Read the slide.
– Answer 3 of the questions that follow the
information.
– Read the procedure. You can get the test
tubes and practice measuring and what you
will do.
Why is dissolved oxygen important to aquatic ecosystems?
Why are natural waters with high DO levels most likely to be healthy?
What sorts of human changes to the aquatic environment do you think
could affect the availability of DO?
What affect do high levels of bacteris fro sewage pollution have on the
amount of DO? Why might this be so?
Could too much DO be a problem in an aquatic system? What could
happen?
What is nitrate, and how is it used?
How is nitrate released into aquatic (water) systems?
What happens if there is too much nitrate in the water system?
What is the main source of excess nitrate?
What is phosphate?
What can high levels of phosphate lead to?
What are sources of phosphate in an aquatic system?
What kinds of evidence might a community find to indicate that
their phosphate level is too high?
Should phosphates be banned from use in industry?
What is pH a measurement of?
What do the values of 0, 14 and 7 represent on the pH scale?
What is the pH range of natural water?
Why is it important to maintain the pH level of an aquatic system?
What factors can affect pH of water?