Comparison of Total Fecal Coliform Bacteria and E. coli

in Pond vs. Lake Waters

by: Amy Bieniek & Stacy Koprowski

11/30/00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Abstract

In this experiment we tested pond and lake water for total fecal coliform bacteria. Data was collected from sixteen sites; eight ponds and eight different sites at Lake Michigan. Using a coliform membrane filtration technique we were able to detect total coliforms and the presence of E. coli. Pond water had more total coliform bacteria including Escherichia coli (E. coli) then lake water.

Key words to index this experiment include: E. coli, coliform, water

Introduction

The coliform bacterial group consists of several genera of bacteria belonging to the family enterobacteriacae. E. coli is considered the most common member of the family enterobacteriacae (Brown 1995). These mostly harmless bacteria live in soil, water, and the digestive system of animals. Fecal coliform bacteria that belong to this group are present in large numbers in the feces and the intestinal tracts of humans and other warm-blooded animals (Todar 1997). These bacteria enter water bodies from human and animal waste. If a large number of fecal coliform bacteria (over 200 colonies/100 milliliters (ml) of water sample) are found in water, it is possible that pathogenic organisms are also present in water. Fecal coliforms by themselves are usually not pathogenic; they are indicator organisms, which means they may indicate the presence of other pathogenic bacteria (Brown 1995). Swimming in waters with high levels of fecal coliform bacteria increases the chance of developing illness from pathogens entering the body (Murphy 2000).

Coliform bacteria thrive in water enriched with waterfowl droppings, especially when ducks and geese use the pond year round. For ponds used for swimming, maintenance for one pair of domestic ducks or geese per surface acre (surface acre = total m of shoreline) of water is discouraged. In ponds where turbidity is high, there is an excessive growth of microorganisms (Norland 1998).

We decided to do this experiment because of the obvious problem we have with pollution of our waters. Water suppliers have often implicated roosting birds for fecal contamination of their surface waters (Alderisio and DeLuca 1999). Geese and gulls have been the primary targets of the blame, and at all sites we tested they were prevalent. We will give quantitative results that should show greater total fecal coliform bacteria in ponds due to them being smaller, and more concentrated areas of water. A test done in Westchester County, N.Y. over a two-year period showed that gull feces contains 3.68 x 108 concentration of fecal coliform bacteria per gram, and geese feces contains 1.53 x 104 fecal coliform bacteria per gram (Alderisio and DeLuca 1999). In this experiment we will use a t-test to determine whether the pond and lake waters are significantly different in fecal coliform bacteria. We hypothesized that pond water will have more total coliform bacteria containing E. coli then Lake Michigan.

Materials/Methods

On October 31, 2000 sixteen samples were collected from eight different ponds and eight different sites at Lake Michigan (See appendix A&B). We obtained approximately 150 ml of water per site in sterile specimen jars. Following the Membrane Filtration protocol we tested our samples within 24 hours of collection. All testing procedures were performed under a hood to ensure sterility. Using a sterilized forceps, we placed a sterile absorbent pad (filter paper) in a sterile petri dish. M-coliBlue24 Broth was added with a micropipette to the petri dish and the lid was replaced. The membrane filter apparatus (generator with tubing) was set up. Using a sterile forceps, we placed a grid into the assembly. After adequately mixing the sample we poured 100 ml into the apparatus and applied suction. The water was filtered to the bottom of the apparatus while the specimen remained fixed to the grid. Using a sterile forceps we transferred the grid to the previously prepared petri dish. The dishes were inverted and placed in an incubator set at 35 C. After 24 hours the dishes were observed and colonies were recorded.

*Steps were repeated for each sample

 

Results

The following data represents the observations and recordings derived from the ponds and lakes. A statistical T-test was performed to determine the level of significance between total colifrom in ponds and Lake Michigan. The p-value is 0.046827169 indicating the data is statistically significant. (A p-value below 0.05 is generally considered statistically significant)

Table 1: Observations and Recordings

Ponds

Total Coliform: Red + Blue Colonies

E. Coli: Blue Colonies

Humboldt

37

7

Grant

25

9

Whit all

17

11

Jackson

153

149

Save land

102

73

Kosciusko

149

141

Sheridan

35

15

Wilson

317

300

Total

835

705

Lake Michigan

Total Coliform: Red + Blue Colonies

E. Coli: Blue Colonies

Bender

13

0

Grant

52

20

Bay View

151

50

S.S.Y.C

27

10

River Launch

9

0

McKinley

12

5

Juneau

153

29

Bradford

150

76

Total

567

190

*You can see from the table that our hypothesis is supported. The ponds have more total fecal coliform and E. coli then Lake Michigan.

Table 2: Interpreting Results

Coliform density is reported as the number of colonies per 100 ml of sample. In order to quantify the data we used the coliform density equation:

Coliform colonies per 100 ml = Coliform colonies counted X 100

ml of original sample filtered

 

 

Coliform colonies per 100 ml

E. coli colonies per 100 ml

Humboldt 74%

14%

Grant 50%

18%

Witnall 34%

22%

Jackson 306%

298%

Saveland 204%

146%

Kosciuszko 298%

282%

Sheridan 70%

30%

Wilson 634%

600%

 

 

 

 

Bender 265%

0%

Grant 104%

40%

Bay View 302%

100%

S.S.Y.C. 54%

20%

River Launch 18%

0%

McKinley 24%

10%

Juneau 306%

58%

Bradford 300%

152%

 

 

 

 

 

Graph #1

*This graph shows the total coliform and E. coli present in ponds. The total coliform includes E. coli and other bacteria. The presence of E. coli is significantly disproportionate to the total coliform.

Graph #2

*This graph shows the total coliform and E. coli present in Lake Michigan. E. coli makes up only a small portion of the total bacteria coliform.

Graph #3

*This graph shows a comparison between pond vs lake total E.coli and total coliform.

Discussion

The presence of fecal coliform bacteria in aquatic environments may indicate that the water has been contaminated with the fecal material of man or other animals. At the time this occurred the source water could have been contaminated by pathogens, disease producing bacteria or viruses that also exist in fecal material. The presence of fecal contamination is an indicator that a potential health risk exists for individuals exposed to this water. Fecal coliform bacteria may occur in ambient water as a result of the overflow of domestic sewage or non-point sources of human and animal waste (Cooke 2000).

According to the results pond water contained a higher amount of total fecal coliform along with a very significant disproportionate amount of E. coli to the total coliform compared to the water taken from different sites in Lake Michigan. These findings are consistent with the hypothesis that water samples collected at the ponds should contain more total fecal coliform containing E. coli than the water in Lake Michigan.

Appendix A

(WDNR 2000)

Appendix B

Literature Cited

Alderisio, K.A., & N. Deluca. 1999. Seasonal Enumeration of Fecal Coliform Bacteria from the Feces of Ring-Billed Gulls (Larus delawarensis) and Canada Geese (Branta canadensis). Applied and Environmental Microbiology. 65, No. 12

Brown, J. (1997, September). What the Heck is an E. coli ? Bugs in the News. Retrieved from the World Wide Web: http://falcon.cc.ukans.edu/~jbrown/ecoli.html.

Cooke, K. (2000, October). Fecal Cloiform Bacteria. Kentucky Water Watch. Retrieved from the World Wide Web: http://www.state.ky.us/nrepc/water/wcpfcol.htm.

Murphy, S. (2000, August). General Information on Fecal Coliform. City of Boulder/USGS Water Quality Monitoring. Retrieved from the World Wide Web: http://www.bcn.boulder.co.us/basin/data/FECAL/info/Fcoli.html

Norland, E. (1998, November). Potential Pond Problems. Ohio Pond Management. Retrieved November 7, 2000 from the World Wide Web: http://www.ohioline.ag.ohio-state.edu.

Todar, K. (1997, April). Bacteriology 330 Lecture Topics: Pathogenic E. coli. Bacteriology at UW-Madison. Retrieved from the World Wide Web: http://www.bact.wisc.edu/Bact330/lactureecoli.