Escherichia coli and coliform levels in the Milwaukee River

Chelsea Marx and Marie Havaich

 

Abstract

            This experiment was designed to see if there was a correlation between the number of colonies of Esherichia coli and fecal coliform in the Milwaukee River and the distance from Lake Michigan. To gather our data, we started on the North Hampton Avenue entrance of Estabrook Park in Milwaukee, Wisconsin and worked our way downstream until we encountered Lake Michigan.  We took two water samples from 20 different sites we chose haphazardly.  After plating our samples, we counted the number of colonies from each site. The data showed that there was no correlation between the distance from Lake Michigan and the number of coliform and E. coli colonies (E. coli, R2= 0.0713; coliform, R2= 0.6463 concluding that E. coli and coliform levels vary throughout the Milwaukee River. However, there were increased levels of coliform colonies at the intermediate sites.     

Keywords:  coliform, Lake Michigan, Milwaukee River, E. coli, water pollution

 

Introduction

            Escherichia coli and other fecal coliforms have the ability to grow in fresh and sea water, especially where there is elevated animal and human contact (Miescier & Cabelli, 1982).  E. coli is a bacterium that is found in the gut of most animals, including humans, and helps with the breakdown and digestion of food.  Though it is found in humans, they are not immune to all forms.  E. coli that the body is not used to can be harmful. It can cause vomiting, fever, diarrhea, belly pains, fatigue, frequent urination, and can develop into hemolytic uremic syndrome (Center for Disease Control and Prevention, 2008). To avoid E. coli and other fecal coliform infections it is necessary to stay away from swallowing lake, river, and sea water.  Infection can occur after ingestion; therefore it is beneficial to wash your hands after coming in contact with such forms of water.

The Milwaukee River runs throughout the eastern side of Wisconsin, starting in the southeast corner of Fond Du Lac county, running though several counties and all the way down to Lake Michigan in downtown Milwaukee.  Most of the river is surrounded by forest and some locations are surrounded by urban structures, like condos, roads, and restaurants.  Currently, the Milwaukee River is being contaminated by sewage, ultimately increasing the amount of fecal coliform found in the water (Wisconsin Department of Natural Resources, 2001). This led us to question the amount of fecal coliform found in the Milwaukee area.  Our hypothesis was that E. coli and other fecal coliform bacterium would be highest near Lake Michigan.

Materials and Methods

            At 0900 on October 8, 2009, our group went to the North Hampton Avenue entrance of Estabrook Park in Milwaukee, Wisconsin to start collection of our water sample. Starting at this location we took two samples using a net about 1.22 meters in length.  We tied two sterile plastic containers to the netting material and immersed them into the river reaching out as far as the pole could reach.  We traveled downstream about 13 Km taking a total of forty samples from twenty different sites finishing at the end of Erie Street at the Riptide Restaurant pier (Table 1).  The sites we chose to collect our water samples from were chosen haphazardly due to limited accessibility to the river.  We collected our samples within a 12 hour period ending at 1700; the day was cloudy and rainy.

            To collect our data we used 3MTM PetrifilmTM E. coli/Coliform Count Plates.  On October 9th, after refrigeration, we used aseptic techniques to place one milliliter of each water sample on a PetrifilmTM E. coli/Coliform Count Plate and labeled the plate with the corresponding site. We then incubated the plates for three days at 37o C and then began counting the colonies on each plate.  Red colonies with gas bubbles were recorded as hazardous fecal coliform, and blue colonies with gas bubbles were recorded as hazardous E. coli.  Using Microsoft Excel 2007, we charted the number of colonies found from each sample and used the program to make correlation calculations.

Table 1- Site Locations on the Milwaukee River where water samples were extracted

 
 

 


Site Number

Location

1

Hampton St Entrance of Estabrook Park

2

Downhill picnic area 8 Estabrook Park

3

Hubbard Park

4

Under East Locust Street bridge

5

About 300 meters South of Locust Street bridge

6

North side of North Ave bridge

7

South side of North Ave bridge

8

Pierce Street and Commerce Street

9

Holton Street Bridge

10

Cherry Street Bridge

11

Juneau Street Bridge

12

Kilbourn Street Bridge

13

Between Wells Street and Wisconsin Ave

14

Between Michigan Street and Clybourn Street

15

At watershed near St. Paul Ave

16

Between Milwaukee Ave & Buffalo Street by Milwaukee Ale House

17

Near Water Street Bridge by Fratello’s Restaurant 

18

Near Erie Street and Milwaukee Ave

19

Jackson Street and Erie Street

20

End of Erie Street at Riptide Restaurant pier

 

Results

            Our results show that there is no correlation between the distance from Lake Michigan and the amount of coliform and E. coli colonies (E. coli, R2= 0.0713; coliform, R2= 0.6463; Figure 1).  We got our R2 value by choosing between different trend lines through the Excel program to find the one with the highest R2 value; the polynomial trend line had the greatest R2 value for each.  

            The location with highest E. coli and coliform levels was found from our 13th site located between Wells Street and Wisconsin Avenue on the river (20 colonies of coliform; 7 colonies of E. coli).  Three different locations had the same levels of E. coli colonies (Site 2, sample 3; Site 6, sample 12; and Site 13, sample 25).  The areas with lowest colonies of E. coli and coliform were located throughout the distance of our sites. The greatest number of coliform colonies was found between sites 8 (sample 16) and

17 (sample 34). 

 

 

 

 

 

 

 

 

 

Figure 1- E. coli and coliform colonies counted for each site location.  The lower the number of location sites the further from Lake Michigan. 

 

 
 

 


Discussion

            There was no correlation between the distance from Lake Michigan and the amount of coliform and E. coli colonies, concluding that E. coli and coliform levels vary throughout the Milwaukee River.  In the end, these results refuted our hypothesis that E. coli and coliform levels would be greater the closer we got to Lake Michigan.

            Though our results did not support our hypothesis, some factors may have contributed to the variability of E. coli and coliform levels.  One of these factors could have been the time of year.  E. coli and other coliform grow at an optimal temperature of 37o C (Nelson, Attwell, Dawson, & Smith, 1996).  On this day, air temperatures ranged from 8.3o C and 11.7o C.  Another factor that could have affected our results could be that we did not inoculate and incubate our plates until the following day and refrigerated our water samples until that point.  By inoculating our plates right away we could have achieved more accurate results because there would be less time for growth and/or death of our bacteria. Future experiments can eliminate this possible error by preparing the plates immediately after samples are taken from the river.

            Something we would change in this experiment would be to test the entire length of the river.  By doing this we could have a more complete picture of the fecal coliform bacterial growth throughout the Milwaukee River.  Also, it would be beneficial to take samples from the river throughout the year, at least one sample per season.  This also could give a more complete picture of fecal coliform bacterial growth throughout the Milwaukee River and could show how temperature affects the growth in fresh water. Pollution has been correlated with fecal coliform bacterial growth; therefore, it would be beneficial to identify pollution sources on the Milwaukee River to compare fecal coliform bacterial growth (Wisconsin Department of Natural Resources, 2001). Further it would be beneficial to find the number of harmful E. coli and coliform bacterium in a specific measurement of water. By doing this we could decide if the water is hazardous to human health.  Safe E. coli and coliform levels range about 77 microorganisms to 100 mL of water (Vermont Department of Health , 2005).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Literature Cited

 

Center for Disease Control and Prevention. (2008, March). Escherichia ecoli. Retrieved November 7, 2009, from Department of Health and Human Services: Center for Disease Control and Prevention: www.cdc.gov/ecoli/

Miescier, J., & Cabelli, V. (1982). Entercoccie and Other Microbial Indicators in Municipal Wastewater Efluents. Water Pollution Control Federation , 54 (12), 1599-1606.

Nelson, S., Attwell, R., Dawson, M., & Smith, C. (1996). The Effect of Temperature on Viability of Carbon- and Nitrogen-Starved Escherichia coli. Microbial Ecology , 32 (1), 11-21.

Vermont Department of Health . (2005). Coliform Bacteria in Water . Retrieved December 1, 2009, from Vermont Department of Health : http://healthvermont.gov/enviro/water/coliform.aspx

Wisconsin Department of Natural Resources. (2001). The State of the Milwaukee River Basin. Milwaukee: Wisconsin Department of Natural Resources. Retrieved November 7, 2009 from http://dnr.wi.gov/org/gmu/milw/milwaukee_801.pdf