Fecal Coliform Testing Lab Report

I. TITLE: Fecal Coliform Testing ; M. Zinkievich , L. Moore ; APES ; Wends. Oct 21 2015

II. INTRODUCTION:

Purpose: What is the amount of fecal coliform in my sample - from Fall Creek Reservoir? Is my water potable, safe for swimming and safe for incidental contact?

Background: Fecal Coliform is a bacteria that grows in the intestinal tract, and is expelled during defecation. This means that where it is found has a source of raw sewage near it, being a leak in a septic system, or animal droppings. This is not good, because the feces are usually a large food source for harmful, disease causing bacteria, such as E. coli or other pathogens. It is important that we measure fecal coliform around recreational areas to make sure that we are not infecting

RESULTS:

For our negative sample, Sterile buffer, we counted 0 colonies on the filter after 24 hours in the incubator at 44.5 degrees centigrade. For our sample, water from the Fall Creek Reservoir, we counted 127 colonies on the filter after incubation. For our positive sample, a diluted broth of E. coli, we counted 38 colonies on the filter after incubation.

The expected levels for the Fall Creek Reservoir, which is mainly a source of drinking water, is 0 CFUs. Our water sample has 127 CFUs. However, because the water has not been filtered at all, this makes sense. This water is relatively clean though, it is well below the 200 CFU desired amount for swimming.

VI. DISCUSSION/ANALYSIS:

On our sample, we counted 127 CFUS. This number is surprising for two reasons. One, the fact that the amount of fecal coliform in this open body of water is so low. It is true that the permissible level of CFUs in drinking water is 0, however, the permissible count of CFUs in swimming water is preferably 200. Significantly higher than the 127 measured in our sample. This shows that the residual amount of coliform is not from any large flows of raw sewage, but is most likely simple from the fact that animals defecate near, and in the open water. This is inevitable, and is not terribly harming. The second reason that this number is surprising, is that this water is supposed to be used for household and domestic use, which it is not permitted to be used as. So, from this point, I can imagine

We had thought that the positive would yield more colonies than it did. We thought that it would grow an amount that was TNC, but instead, it had 38. This was simply an overestimate on the potency of the E. coli broth that was filtered for this plate. The negative however, does support our hypothesis. We had predicted that there would be 0 colonies on the filter, and we were correct. The sterile buffer that we filtered, gave yield to 0 colonies. We were slightly off on our prediction for our sample. We thought that there was going to be approximately 25 colonies; instead, there were 127. This was an overestimate on the cleanliness of the