The Effects of Various Pollutants on Aquatic Pond Life
Science Fair Projects

Water & Soil Microbes Experimenter Kit	Surface Microbes Experimenter Kit	Student's Microscopes
Age 10 +	Ages 10 and up	Ages 8 thru Adults

Purpose

The purpose of this experiment was to determine the effects of various pollutants on a daphniaís heartbeat.

I became interested in this idea when I noticed articles in magazines and books saying that our water was becoming polluted and killing pond life.

The information gained from this experiment may help people understand the detrimental effects of pollution on pond life.

Hypothesis

My hypothesis is when the pollutant is added to the daphniaís water, it will slowly die due to intoxication. I think the gasoline or the weed killer will be the most toxic and kill the daphnia quicker. I think the control group, the ice melter, and the antifreeze will be less toxic.
I base my hypothesis on information I found on the Internet that scientists who had performed similar experiments put there.

Experiment Design

The constants in this study were:

-The type of daphnia.
-The intervals between checking the daphniaís heartbeat
-The size and type of rubber ring
-The period of time between each trial

The manipulated variable was type of pollutant added to the daphniaís water.

The responding variable was the daphniaís death rate per minute.

To measure the responding variable I used my sight to count the daphniaís heartbeat.

Materials

Procedures

1. Gather materials needed.
2. Complete steps 3-8:
3. Gather 5 glass quart-canning jars. (Make sure they are clean).
4. Take one jar and add 500 ml. of water for your control group.
5. In jar #2 add 5 ml. of gasoline and 500 ml. of water and mix well.
6. For the third jar, add 5 ml. of automobile radiator antifreeze, and 500 ml. of water. Mix well.
7. For the fourth jar, add 5 ml. of ìRoundup Weed killerî (diluted to application rate), and 500 ml of water. Mix well.
8. For the last jar, add 5 grams. of dry driveway ice melter, and 500 ml. of water. Mix well.
9. Label all the jars with the pollutant they contain.
10. Set up the jars in a row in the work area.
11. Place a Petri dish in front of each jar. Distribute 5 clean plastic rings in each Petri dish to act as corrals for the daphnia. Label the rings A, B, C, D, and E. Add 25 ml of liquid from jar #1 to Petri dish #1.
12. In a similar manner add liquid from jar #2 to Petri dish #2. Repeat with 3, 4, and 5.
13. Set up a microscope with 40-power magnification in a safe place.
14. Set up a timer by the microscope.
15. Take an eyedropper and collect one daphnia and place it in the first plastic corral in Petri dish #1.
16. Repeat step 14 for the other four corrals. Try to work quickly, but gently.
17. Place the Petri dish under the microscope.
18. Check daphnia ìAî for a heart beat for 15 seconds. Record whether daphnia is alive (heart beat can be seen) or dead (no observable heart beat), and repeat for the other four daphnia.
19. Set timer for 1 hour.
20. Repeat steps 15 ñ 18 for the other 4 liquids (pollutants.)
21. When the timer goes off observe the daphnia in Petri dish #1 in the same order (A, B, C, D, E), checking the daphniaís heartbeat for fifteen seconds each using the microscope. Record ìaliveî or ìdeadî.
22. Reset timer for 1 hour.
23. Repeat step 21 for the other 4 liquids (pollutants) in the same order as in step 20.
24. Repeat steps 21 ñ 23 until a total of 8 observations have been made.
25. Discard daphnia and clean Petri dishes.
26. Repeat steps 11- 24 two more trials.
27. Average the results from all three trials.

Results

The original purpose of this experiment was to determine the effects of various pollutants on Daphnia.

The results of the experiment were the Gasoline and the ice melter killed all five daphnia each on hour one. The Antifreeze and the water were about the at the same pollutant level. The antifreeze killed one to two daphnia in each test. When the daphnia died on any of the pollutants between hour one, and hour two, I assumed it was because of natural causes, with the exception of the Gasoline and Ice melter. The weed killer (Round Up) killed most of the daphnia between hour 5-6, accept for trial two when four of them lived to hour eight. All three trials turned out very similar results.

Conclusion

My hypothesis was, when the daphnia come in contact with the pollutants; they will slowly die due to intoxication.

The results indicate that this hypothesis should be partly accepted. The gasoline was the most toxic pollutant. But the daphnia lived fairly well in the weed killer. The Ice melter was also very toxic. It killed them in the first hour. The daphnia lived the best in the antifreeze and the controlled group. The results show that the hypothesis should be partly accepted.

Because of the results of this experiment, I wonder how much pollution in water is needed to actually kill daphnia. The amounts of pollution I added to the daphniaís water are probably much larger than you would find in water. So I wonder how much pollution is actually needed. If these large amounts killed them off so easily, how would a smaller amount affect them? I also wonder if the pollutants would have different effects on a different type of marine fish such as salmon.

If I were to conduct this project again I would use more pollutants. I would also do more trials and have more daphnia per trial. I would try to make the whole experiment more accurate so I could present better results. I would also try to take more time to do my experiment to make sure I did it right. The Effects of Various Pollutants on Aquatic Pond Life Research Report