Transcript Levels of Pollutants in Local Waters

Levels of Pollutants in Local Waters
Emily Young Carr
Grade 9
Academy of Notre Dame de Namur
Problem
o Is there a direct correlation between the extent of
pollution in local waters and the location of the
body of water?
Research
o Factors that cause water pollution include…
• Industry- many companies dispose of waste in freshwater sources
like rivers.
• Sewage and Wastewater- increases with a high population density
and the presence of industry.
• Thermal pollution- when heated water is released into a body of
water, often an industrial practice
o Some common tests used to evaluate purity of water are pH
balance, buffering capacity, and level of bacterial contamination.
o pH balance measures how acidic or basic a substance is, 0-14, the
higher the more basic. 7 is neutral.
o A normal pH measurement for freshwater should be between 6.5
and 8.
o Major or sudden changes in pH balance are stressful for the
water’s ecosystem.
Research
o Buffering Capacity is the amount of acid or base needed to
change the pH balance of a solution.
o A high buffering capacity indicates the water tested is hard
water while a low buffering capacity indicates soft water.
• Hard water is water with a high mineral content (common
minerals are calcium and magnesium); soft water is the
opposite.
• Water pollution is not linked with only hard or soft water.
Hypothesis
o If a body of water lies in close proximity to industry, and/or
there is a high population density in the area, then higher
levels of pollutants will found in the water.
Necessary Materials
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9 sterile 50mL conical tubes
27 sterile 14mL round-bottom tubes
Pipettes of varying size
Pipette aid
9 LB agar plates
Bacteria loops
54 mL of LB broth
Diluted HCl at .02 N HCl
pH meter
Shaker incubator
Bunsen burner with fire source
Cold room
Water from 9 different local bodies of water
Procedure (Water Collection)
o Eight local bodies of water were chosen from which to
collect water samples.
o The first five samples were collected from suburban bodies of
water. The bodies of water from one to five are: Darby
Creek, Harriton Plantation Pond, Rhoads Pond, Dove Lake,
and Mill Creek.
o The remaining three samples were collected from urban
bodies of water. The bodies of water from six to eight are: the
Delaware River, the Schuylkill at the Boathouses, and the
Schuylkill at the Gladwyne Exit.
o All samples were gathered in 50mL conical tubes.
Procedure (pH balance)
o The pH meter was standardized to pH7.
o The pH of the eight water samples and the control were
tested.
o Tests were done three times for each sample for statistical
significance.
o The probe was cleaned after each sample was tested.
Procedure (Buffering Capacity)
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14 mL tubes were filled with 2 mL of water sample per
tube, 3 tubes for each water sample
The pH meter was standardized to pH7.
Acid (HCl) was added in μL increments to the water
sample until it reached the neutral measurement of pH 7
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HCl Concentration: 0.02 N HCL
Tests were done three times for each sample for statistical
significance.
o The probe was cleaned between tests.
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Procedure (Bacterial Growth)
o 14mL tubes were labeled 1-9 with 3 tubes per water sample.
o The tubes were filled with 2mL of LB broth and then 20μL of
water sample was added using a pipette aid.
o The 27 tubes were put into a shaker incubator at ideal bacterial
growth conditions and left in overnight.
• 37 degrees C
o 9 LB agar plates were separated into thirds and the thirds were
labeled A, B, and C.
o Plates were streaked, each of the three bacterial cultures for a
water sample were put into a different third.
o Plates were stored in 37 degrees C oven and bacteria was allowed
to grow overnight.
o Plates were evaluated for bacterial colonies the next day.
Variables
o Independent Variable- the water samples from varying bodies
of water
o Dependent variable- pH balance, buffering capacity, and
bacterial growth
o Control- tab water from laboratory facility
o Constants- the materials used; the amount of water sample
collected; the amount of LB broth used per sample; the
temperature of the lab facility, cold room, shaker incubator,
and water samples; the location of experimentation; and the
amount of time allowed for bacterial growth and observation
Data and Results
o Abbreviations:
 Darby Creek: WS1
 Harriton Plantation Pond: WS2
 Rhoads Pond: WS3
 Dove Lake: WS4
 Mill Creek: WS5
 Delaware River: WS6
 Schuylkill at Boathouse: WS7
 Schuylkill at Gladwyne Exit: WS8
 Tap Water from a Lab Facility: Control
pH Measurements
7.9
Water Sample pH Measurements
pH Measurements with Standard Deviation
7.8
7.7
7.6
7.5
7.4
7.3
Series1
7.2
7.1
7
6.9
6.8
Control
WS1
WS2
WS3
WS4
Water Samples
WS5
WS6
WS7
WS8
Buffering Capacity
Buffering Capacity in μL with Standard Deviation
80
Water Sample Buffering Capacity
70
60
50
40
Series1
30
20
10
0
Control
WS1
WS2
WS3
WS4
WS5
Water Samples
WS6
WS7
WS8
100
Bacterial Growth
Water Sample Bacteria Growth
Percent of Tests with Bacterial Growth
90
80
70
60
Series1
50
40
30
20
10
0
Control
WS1
WS2
WS3
WS4
Water Samples
WS5
WS6
WS7
WS8
Conclusion
o Hypothesis- If a body of water lies in close proximity to
industry, and/or there is a high population density in the
area, then higher levels of pollutants will found in the water.
o The hypothesis was neither supported nor unsupported
• Results too vague to clearly support correlation
• Higher percent of urban bodies of water had bacteria, but some
suburban bodies of water had bacteria also
• Did not consider extent of agricultural pollution
o Possible Errors and Improvements
• There should be a greater number of water samples from both
groups
• More tests could be preformed to test pollutants in water
Recognitions
o Thank you to all sources used.
 Pollution by Debra A. Miller
 “EPA to Staunch Flood of Storm Water Runoff Polluting U.S. Waterways”
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Scientific American
“Water Pollution” http://en.wikipedia.org/wiki/Water_pollution
“Water Pollution and Society”
http://www.umich.edu/~gs265/society/waterpollution.htm
“On Course for a Cleaner Hudson” The New York Times
“Optimum Freshwater pH” http://www.bestfish.com/tips/102998.html
“Hard vs. Soft Water Explained”
http://www.freedrinkingwater.com/water-education
“The Causes of Water Pollution” http://www.waterpollution.org.uk/causes.html
o Thank you to everyone in the audience for listening to my
presentation. I would be happy to answer any questions you
may have about my project.