Ryan Church
Per. 2-3
Testing for Fecal Coliforms
Purpose:
The purpose of this lab was to test the water for fecal Coliforms. We will do this by testing water sample from the river, the pond, and the tap. After we acquire the water we put it in a vile and then into a petri dish to sit and develop the coliforms. Hypothesis:
I believe that we will see a lot of fecal coliforms in the river and in the pond but not in the tap because it goes through a filter, and does not come in contact with animal waste. Data/ Observations: Class Data # of E. coli colonies per 100 mL | Location of the water sample | 33.3 | River | 89.9 | Pond | 0 | Tap |

We could tell that the colonies were E. coli colonies because their color was blue/purple. We tested for the E. coli colonies because that is what made the water in the river and pond dangerous to drink. Even though you cannot drink the water in the river and pond you can still swim in it because they had less than 200 E. coli colonies per 100mL. Analysis:
1a. In this experiment our independent variable was the location that we get the water because it is what we change.
b. In this experiment the dependent variables was the number of E. coli colonies because it is what we measured.
c. In this experiment the controlled variables were the temperature that the water sat in, the amount of sunlight, and the solution that we used to observe the E. coli colonies.
2. After calculating the amount of E. coli colonies per 100 mL in the River we could safely swim in it. The standard numbers of E. coli colonies were 200 per 100mL of water and we had 33.3 E. coli colonies per 100mL.
3. We tested the number of E. coli colonies in the tap water because we had to make sure that the water that we drink is safe to drink. Also, it was important to test these because if we did not we would not have had any controlled group to compare the other data too.
4. The presence of fecal coliforms bacteria is an important indicator of health risks because if there are fecal coliforms in the water then there is bound to be pesticides in the water as well. The pesticides are what may cause diseases, and that is what we were scared of having in the water.
5. Local beaches have to close when the E. coli count is too high because if they do not people can get diseases from the E. coli being too high.
6. I believe that in the winter the fecal coliform counts would be way down because it said that it has trouble thriving when the temperatures are lower. Also, after heavy rainfall the counts can be lower if there is not a lot of runoff, but if there is a lot of runoff than the counts would be very high. Conclusion:
After the testing we found that the water does not have that many E. coli colonies. In the river there were 33.3 per 100mL of water and in the pond there were 89.9 per 100mL of water. After testing I found that my hypothesis was partly correct because I said that there would be a lot in the river and pond and none in the tap, which was right it was the fact that there was not a lot of fecal coliform in the river and pond there were not a lot at all. Some potential error could have been from leaving the vile with the solution open for too long. This would affect the lab because some of the bacteria in the solution would have gotten out and we would not have gotten an accurate fecal coliform count. Also, if we got a lot of the fecal coliform we could have miscounted them and skewed the data. Lastly, if we could do the lab again I would have tested from different parts of the river and pond because at different points in the water the coliform count could be different as well.