How Various Pollutants Affect Daphnia

Researched by Rob B.


The purpose of this experiment was to determine the effect of various pollutants on the survival of daphnia.

I became interested in this idea when I noticed all the problems that water pollution was creating and what harm it would do to not only sea life, but to humans too. 

The information gained from this experiment will help people realize which pollutants damage water life. Since all life is connected in a food web, any pollutants that kill daphnia or other micro life could affect all other life including humans.

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My hypothesis is the petroleum-based pollution will be more effective in killing the daphnia than other pollutants. 

I base my hypothesis on The World Book Encyclopedia and a book called Our Poisoned Waters. They both say that Oil spills are most effective in killing sea life.

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The constants in this study were:
* Do all the experiments at the same time.
* Put the same amount of pollutants in at a time.
* Put the same amount of water in each container.
* Put the same amount of light over each container.
* The amount of daphnia faced to the pollution.
* The same dropper to put the daphnia in with the polluted water

* The manipulated variable was the pollutants that I put in with the daphnia.

* The responding variable was the amount of time the pollutants took to kill the daphnia. 

* To measure the responding variable must check the daphnia frequently to see how long it took for the daphnia to die in the pollutant.

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Item Description
1000 mL. Pond Water
25 Daphnia
1 Eyedropper
1 Microscope
5 mL. Petroleum based pollutant
5 mL. Antifreeze
5 mL. Weed Killer
5 mL.  Diazinon
5 Petri Dishes
25 Plastic rings
5 Quart size jars
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1. Gather all the materials needed.
2. Complete steps. 
3. Gather 5-quart size jars (must be clean).
4. Put 100 ml. of water in jar #1 for your control group.
5. In jar #2 add 100 ml. of water plus 10 ml. of petroleum based pollutant (oil) and mix well.
6. In jar #3 add 100 ml. of water plus 10 ml. of antifreeze.
7. In jar #4 insert 10 ml. of "Weed Killer" with 100 ml. of water.
8. In jar #5 place 10 ml. of a pesticide called "Sevin" with 100 ml. of water.
9. Set them side by side in the workplace. 
10. Label each jar with the pollutant it contains.
11. Get five petri dishes and mark them as A, B, C, D, and E.
12. Get five plastic rings; mark them 1, 2, 3, 4, and 5. These are used to act like corrals for the Daphnia.
13. Set ring #1 in petri dish A, and insert 50 ml. of the liquid from jar #1.
14. After doing this enter the daphnia in with an eyedropper in with the polluted liquid.
15. Set up a timer and time it for one hour.
16. After the timer goes off, take the petri dish under a microscope and examine the daphnia to 
       see if its heart is beating.
17. Once you are finished insert the data into the computer to make a couple of graphs. 
18. Take the liquid from jar #2 and insert it into petri dish B.
19. After this is done enter the daphnia in with the liquid from jar #2.
20. After an hour examine and write down the data.
22. Repeat steps 14 ? 18 in each experiment.
23. Once you get all the information create a diagram of the information.

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The original purpose of this experiment was to test various pollutants on the survival of Daphnia.

The results of the experiment were Diazinon, Antifreeze, and Ortho Weed Killer, were most hazardous to the Daphnia. The petroleum-based pollutant was the least affective in harming the daphnia. 


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My hypothesis was that the petroleum-based pollution will be more effective in killing the daphnia than other pollutants. 

The results indicate that this hypothesis should be rejected, in fact, the oil was the least succesful in harming the Daphnia.

Because of the results of this experiment, I wonder if I should have used more kinds of pollutants and Daphnia to see which one is the most affective. I also wonder what would of happened if I used fresh water and not tap water.

My findings should not be useful to the people of the world because I used tap water and did not check the Daphnia repeatedly.

If I were to conduct this project again, I would like to gather more pollutants and more daphnia to see what pollutant would be most harmful to the Daphnia. I would also like to get fresh water from the habitat of the Daphnia. Another thing I would like to do is put more Daphnia in with the pollutants to test how affective the pollutants are at harming the Daphnia. I also would have liked to use fresh water and not tap water in my experiment.

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Water Pollution is a big problem. People are letting different kinds of pollution into the water, which is killing most of our water life. That is what this report is about. 


Daphnia are a crustacean known as Daphnia Pulex or a water flea.  It is about the size of the led of a pencil (0.25cm to be exact). It has a clear shell for protection.  The only thing that is out of the shell is its long finger that helps them glide through the water. Daphnia reproduce rapidly. They are found in ponds and ditches in The United States and Europe. Daphnia create the order of Cladicera of the class Branchiopada.


There are many pollutants and many ways to get them into our environment.  Sewage, oil or petroleum based pollutant, garbage, there are many different kinds of pollutants and they are released into our water because of our needs. We release sewage the most. It is probably the worst kind of pollutant because it is released into lakes, rivers, and etc. Sewage is the most common and the most feared of pollutants because it makes our waters unattractive and dangerous to the fish. If the fish eat the sewage and then we catch them to eat them, they are infected by our pollution and we get sick from them. This is just the act of the food chain.
 Oil spills are also a big problem. It cuts off the oxygen in our water so the water life canít breath and they die. And if the water life is all gone it goes up the food chain and effects each and every one of us. Now we know that when we pollute our waters it doesnít only affect animals, it affects us too.
 Garbage is also a big factor in the pollution game.  It falls in the gutter and travels through the sewage systems and ends up in our fresh or salt waters. Many fish and other water life die by garbage.  The plastic rings that they use with pop cans sometimes get caught on the fish and they strangle to death.


Sewage makes big effects in our water by its pollution. Sewage uses 85% of fresh water in a year, which leaves us with only 15% in house, hold and outdoors fresh water uses. Oil spill are also hazardous, the oil cuts off the oxygen and gets in fish and other animals and when we eat them, they make us sick. Also sewage and all other human luxuries have used 90% of all our fresh water. 


Daphnia are only apart of water life, but there are millions more and the pollution humans are letting out are killing all of the water life. Sewage, Oil spills, Garbage, all of this is kill the water life, but it is not only them, but humans to. By oil spills humans are putting oil in the fish people eat and are making us ill. See, humans are not only harming animals but themselves too. 

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"Daphnia Pulex" Encarta Deluxe. 1998. Vol. 1 pp. 1-2

Dolan, Edward F. Our Poisoned Waters  Dutton, New York: Cobble Hill Books, pp. 1-20

"Effects of Water Pollution" World Book Encyclopedia,  1991. Vol.21.Pp.1

P. A. McLaughlin. "Water Flea"World Book Encyclopedia,1991.Vol.21. Pp.1

"Water Flea" Encarta. 1996. Vol. 1 pp. 1-2 

"Water Pollution" Encarta.1996. Vol. 1 pp. 1-2

"Water Pollution" Encarta. 1998. Vol. 1 pp. 1-2

"Water Pollution" Encarta. 1999. Vol. 1 pp. 1-2

"Water Pollution" Encarta Deluxe. 1999. Vol. 1 pp. 1-2

"Water Pollution" Encarta. 2000. Vol. 1 pp. 1-2

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