Escherichia coli (E. coli) bacteria normally live in the intestines of people and animals. Most E. coli are harmless and actually are an important part of a healthy human intestinal tract. However, some E. coli are pathogenic, meaning they can cause illness, either diarrhea or illness outside of the intestinal tract. The types of E. coli that can cause diarrhea can be transmitted through contaminated water or food, or through contact with animals or persons (from CDC web site). The EPA has determined that the presence of bacteria is a good indicator of fecal contamination in fresh water.
Logan Martin Lake Protection Association (LMLPA) monitors use Alabama Water Watch bacteriological monitoring protocols to determine “first alert” levels of E. coli in frequently used swimming areas. Our goal is to determine if there are regular occurrences of E. coli counts above the one time alert level of 235 colony forming units (cfu) of E. coli. If so, LMLPA will continue to monitor the site each summer until the situation improves. In prior years of monitoring, we have only seen one example of regular E. coli spikes and that was remedied when the City of Pell City removed many of the geese from the Lakeside Park swim beach.
We monitor once per month to determine a background count and after rain events during which E. coli on the surrounding land mass could wash into the lake. Our samples take from 36-48 hours for any E. coli to grow into a large enough colony to be seen by the naked eye. Thus, our data will always be about 2 days old and only valid for the day, time and place that the sample was taken. Our data cannot be used to predict what the water conditions will be at any future time. It should also be noted that our sample is extremely small (3mL) when compared to the size of the lake.
LMLPA, as well as Alabama Department of Environmental Management (ADEM), discourages swimming or other whole body contact with the water in the immediate area of waste water discharges. For locations of waste water discharges in the Coosa Valley, including Logan Martin and its tributaries, visit coosariver.org.
LMLPA will post concerns of E. coli counts above 235 cfu/100mL as they become available. Remember, you always swim at your own risk.
The free Swim Guide app is available for Apple and Android devices. The Coosa Riverkeeper tests once per week May – Sept. on Thursdays at selected sites around the lake and posts the results on Swim Guide on Friday afternoons.
