Points and Plumes
5
FRUITVALE GROUNDWATER C
ONTAMINATION: INVESTIGATION
Name
________________________________
What are the similarities and differences of point and nonpoint source contamination?
The geologic cross section of Fruitvale showed that a contaminant in
water or another liquid could easily percolate down and spread out
into an aquifer. The part of the aquifer that becomes contaminated is
called a plume. Knowing this, you decide to find out more about how
contaminants move once they have been released onto the earth’s
surface. You discover that substances released into the environment,
harmful or not, can be classified into two categories, depending on
their source. If there is a single source of the chemical, such as a leaky
fuel storage tank or an overturned truck, the contamination is called a
point source. If there are a number of sources, such as millions of
exhaust pipes, or acres of fertilized farmland, the contamination is
called a non-point source. Point source and non-point sources can
produce very different plumes.
Safety Note: Food coloring can stain clothes, and work surfaces. Immediately
rinse any spills with water.
MATERIALS
For each group of four students:
1 spray bottle of “groundwater contaminant”
o Spray bottle has 2 modes: Stream and Spray
For each team of two students:
1 contaminant plume tray (cafeteria tray)
2 moistened paper layers
PROCEDURE
Part A: Point and non-point source plumes in horizontal
layers
1. Place the tray on your table tilted on the plastic tub or a stack of
books.
2. Stack the two moistened paper towels on top of each other on
the tray.
3. Read step 4 & 5. Make a prediction sketch, then do the steps.
4. In STREAM mode, hold the spray bottle about 8 inches
from the towels and squeeze two squirts in one location.
5. In SPRAY mode, repeat the last step in another location.
6. Wait 10-20 seconds then sketch and describe what you observe:
Stream Mode
Spray Mode
Prediction
Actual
7. Carefully peel both layers off the tray and separate them.
Describe, sketch, and compare the appearance of the top
paper layer and the bottom one.
Top Layer
Bottom Layers
Stream:
Spray:
ANALYSIS
1. Which spray mode represented Point Pollution? _____________
Non-point Pollution? ______________
2. Compare and contrast the results for point source and nonpoint groundwater contamination. Which type of contaminant
plume do you think might be easier to clean up? Why?
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Part B: Predicting the Spread of Groundwater Contaminants
How might a contaminant spread under different circumstances in
Fruitvale?
The colored areas you observed on the paper layers represented a
groundwater contaminant plume. The shape and size of a
contaminant plume is affected by a number of factors related to the
contaminant and to the local environment. These factors include the
amount of contaminant released, whether it was a point or non-point
source, the type of earth material through which the contaminant is
spreading, the amount of time the contaminant has been spreading,
the amount of precipitation or irrigation that has occurred during
that time, and the amount and direction of groundwater flow.
(WHOA, WAIT… That was a lot of factors! Go back and read that
again. NUMBER each factor with 1, 2, 3… and UNDERLINE the key
words for each. Go ahead, I’ll wait. How many were listed? _______
Nice job, carry on.)
Part B: Predicting the Spread of Groundwater Contaminants
How might a contaminant spread under different circumstances in
Fruitvale?
The colored areas you observed on the paper layers represented a
groundwater contaminant plume. The shape and size of a
contaminant plume is affected by a number of factors related to the
contaminant and to the local environment. These factors include the
amount of contaminant released, whether it was a point or non-point
source, the type of earth material through which the contaminant is
spreading, the amount of time the contaminant has been spreading,
the amount of precipitation or irrigation that has occurred during
that time, and the amount and direction of groundwater flow.
(WHOA, WAIT… That was a lot of factors! Go back and read that
again. NUMBER each factor with 1, 2, 3… and UNDERLINE the key
words for each. Go ahead, I’ll wait. How many were listed? _______
Nice job, carry on.)
PROCEDURE
Use your Fruitvale Street Map to locate Eat ‘Em Up Berry Farm, the
Orchard, and the Municipal Water Well.
PROCEDURE
Use your Fruitvale Street Map to locate Eat ‘Em Up Berry Farm, the
Orchard, and the Municipal Water Well.
Do the following steps on the Predicting Plumes Using Geologic Cross
Sections page.
Do the following steps on the Predicting Plumes Using Geologic Cross
Sections page.
1. Read the spill descriptions then label each as either point source
or non-point source.
1. Read the spill descriptions then label each as either point source
or non-point source.
2. Use a colored pencil to draw plumes for the scenarios described
on each geologic cross section. Notice what kinds of sediment
layers are underground. This is important!
2. Use a colored pencil to draw plumes for the scenarios described
on each geologic cross section. Notice what kinds of sediment
layers are underground. This is important!
3. Use a different color to circle any wells (there are two on each
map) that are likely to be affected by the contaminant plumes.
EXPLAIN why you circled those wells. Use scientific information
about aquifers, movement of water through soil, point vs nonpoint pollution, your drawings, etc. (answer in notebook)
3. Use a different color to circle any wells (there are two on each
map) that are likely to be affected by the contaminant plumes.
EXPLAIN why you circled those wells. Use scientific information
about aquifers, movement of water through soil, point vs nonpoint pollution, your drawings, etc. (answer in notebook)