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?

Copy this week’s agenda down quietly. 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.

These are the substances you are testing for: pH (if acid or alkaline) 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 Source Effect on health pH (acidity vs alkalinity)* Acid (low pH) Alkalinity, limestone (high pH) Low pH: Sour taste High pH: Bitter metallic taste Nitrate* nitrogen Runoff from fertilizer Infants (< 6 mo.) May become seriously ill/ die Phosphate* phosphorous Sewage; Runoff from agriculture sites; lawn fertilizers Severe exposure: kidney weakened

Read: Contaminants and their Effects Source Effect on health Dissolved oxygen DO 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.

Read the instruction cards in the middle of the table. 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.

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)

A/B will test nitrate and phosphate C/D will test DO and pH. 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?