Levels and their effects ON US!
article written by Bill Byrd from
graphics and verbage on the USGS website
How safe is it for us to swim, wade, fish, and boat in the Chattahoochee River today? The Chattahoochee flows through a VERY highly developed area with increasing warm water runoff, so much of the water quality answer depends on bacteria levels in the water. The Chattahoochee Riverway BacteriALERT provides you with daily bacteria information for three locations on the Chattahoochee River: Medlock Bridge, Johnson Ferry, and Paces Ferry. The map below left shows locations where samples are collected to grow cultures and determine bacteria levels.
Bacteria are common single celled organisms, and are natural components of lakes, rivers, and streams. Most bacteria are harmless to humans, but certain bacteria normally residing in the intestinal tracts of warm blooded animals have the potential to cause sickness and disease in humans. High numbers of these harmless bacteria often indicate high numbers of harmful bacteria as well as other disease causing organisms such as viruses and protozoans. One method of determining the amount of bacteria present is to take water samples and count the number of bacteria colonies from those samples that grow on a prepared medium.
Total coliforms were originally believed to indicate the presence of fecal contamination. Over time total coliforms have been found to be widely distributed in nature, and are not always associated with the gastrointestinal tracts of warm blooded animals. The number of total coliform bacteria in the environment is still widely used as an indicator for potable water in the U.S. The Chattahoochee Bacteria Monitoring Network is sampling for total coliform and E. coli bacteria. Coliform bacteria include fecal coliform, and E. coli.
Fecal coliform bacteria are a subgroup of coliform bacteria that were used to establish the first microbial water quality standards. The ability to grow at an elevated temperature (44.5 C) separate this bacteria from the total coliforms and make it a more accurate indicator of fecal contamination by warm-blooded animals. Fecal coliform bacteria are detected by counting the pink-red colonies that grow on a 0.65 micron filter placed on mFC agar incubated in a 44.5 C oven for 22-24 hours. The presence of fecal coliforms in water indicates that fecal contamination of the water by a warm-blooded animal has occurred, however, recent studies have found no statistical relationship between fecal coliform concentrations and swimmer associated sickness.
Escherichia coli (E. coli) is a rod shaped bacteria commonly found in the gastrointestinal tract and feces of warm blooded animals. It is a member of the fecal coliform group of bacteria and is distinguished by its inability to break down urease. E. coli numbers in freshwater are determined by counting the number of yellow and yellow brown colonies growing on a 0.45 micron filter placed on m-TEC media and incubated at 35.0 C for 22-24 hours. The addition of urea substrate confirms that colonies are E. coli. This bacteria is a preferred indicator for freshwater recreation quality, and its presence provides direct evidence of fecal contamination from warm-blooded animals. Although usually harmless, E. coli can cause illnesses such as meningitis, septicemia, urinary tract, and intestinal infections. A recently discovered strain of E. coli (E. coli 0157:H7) can cause severe disease and may be fatal for small children and the elderly
The relation between bacteria counts and sickness is an indicator of potential health problems. Consumption of or contact with water contaminated with feces of warm-blooded animals can cause a variety of illnesses. Minor gastrointestinal discomfort is probably the most common symptom; however, pathogens that may cause only minor sickness in some people may cause serious conditions or death in the very young, the elderly, or those with weakened immune systems.
Studies have shown that there is not a positive relationship between either total coliform or fecal coliform counts and sickness, but studies have shown a positive relationship between E. coli and sickness. As E. coli counts go up, the occurrences of sicknesses go up. That is why this project is focusing on E. coli as the main indicator of potential risk.
For your health, check on bacteria levels at this website BEFORE you go fishing. After fishing the Chattahoochee when high E. Coli levels are present, disinfect your hands with a good antibacterial soap before eating. Cleanse equipment after use with an anti-bacterial cleaner as well. Common sense will go a long way in keeping your good health.
Thanks to USGS for this wealth of information. For even more information on bacteria and the programs to keep us aware of bacteria counts please click here:
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