Youth water quality tests – Part 6 – Fecal coliform
Teach students about science by playing in the river! You can learn about the pollution in the river by studying fecal coliform.
This is the sixth article in a series by Michigan State University Extension which continues to discuss water quality test conducted as part of Global Rivers Environmental Education Network (GREEN). This international program began along the polluted Huron River in Ann Arbor, Mich. and has developed into a comprehensive educational program. By conducting some simple tests, students can learn about how clean or polluted nearby streams are. Further investigation will allow the students to identify problems and help to improve rivers.
Fecal coliform bacteria are found in the feces of humans and other warm-blooded animals. These bacteria can enter rivers directly, from agricultural or storm runoff carrying wastes from birds and mammals. It can also enter rivers from human sewage discharged that goes into the water. Fecal coliform by themselves are not all dangerous (pathogenic). Pathogenic organisms include bacteria, viruses and parasites that cause diseases and illnesses. Fecal coliform bacteria naturally occur in the human digestive tract and aid in the digestion of food. In infected individuals, pathogenic organisms are found along with fecal coliform bacteria.
If fecal coliform counts are high (over 200 colonies per 100 mL of water sample) in the river, there is a greater chance that pathogenic organisms are also present. A person swimming in such waters has a greater chance of getting sick from swallowing disease-causing organisms, or from pathogens entering the body through cuts in the skin, the nose, mouth or the ears. Diseases and illness such as typhoid fever, hepatitis, gastroenteritis, dysentery and ear infections can be contracted in waters with high fecal coliform counts.
Pathogens are relatively scarce in water, making them difficult and time-consuming to monitor directly. Instead, fecal coliform levels are monitored because of the correlation between fecal coliform counts and the probability of contracting a disease from the water.
Cities and suburbs sometimes contribute human wastes to local rivers through their sewer systems. A sewer system is a network of underground pipes that carry wastewater.
In a separate sewer system, sanitary wastes (from toilets, washers and sinks) flow through sanitary sewers and are treated at the wastewater treatment plant. Storm sewers carry rain and snow melted from streets and discharge untreated water directly into rivers. Heavy rains and melting snow wash wildlife, livestock and pet wastes from sidewalks and streets while may "flush out" fecal coliform from illegal sanitary sewer connections into the storm sewers.
In a combined sewer system, sanitary wastes and storm runoff are treated at a wastewater treatment plant. After a heavy rain, untreated or inadequately treated waste may be diverted into the river to avoid flooding the wastewater treatment plant. To avoid this problem, some cities have built retention basins to hold excess waste water and prevent untreated wastes from being discharged into rivers. Without retention basins, heavy rain conditions can result in high fecal coliform counts downstream from sewage discharge points. That is why it is important to note weather conditions on the days before a fecal coliform measurement.
E. coli vs. fecal coliform
Total coliform bacteria are a group of easily cultured organisms used to indicate water quality. The U.S. Environmental Protection Agency considers any total coliform to be unacceptable in drinking water. Total coliform bacteria consist of environmental and fecal types. Coliforms are easy to isolate, present in larger numbers and usually survive longer in an aquatic environment than viruses, parasites and more serious types of bacteria. Most of the total coliforms are not considered pathogens under normal conditions.
E. coli is a species of coliform bacteria that is directly linked to fecal contamination by the wastes of warm-blooded animals, including humans. Some strains are pathogens in humans.
Non-coliform bacteria are mainly environmental organisms and in large numbers can compete with total coliform and make it difficult for coliform(s) to be detected. High levels of non-coliform bacteria indicate a reduction in water quality.
There are several methods used by volunteers to measure fecal coliform bacteria. They have been discussed by the University of Wisconsin’s Volunteer monitoring program.
Looking at the data and what kids can do to make it better
Fecal coliform is a serious issue which can impact the health of those swimming or wading in the water. Students can work with local health departments and the county board of commissioner to implement more testing of bathing beaches or septic systems. Some counties in Michigan have no requirements that septic systems ever get tested.
Finding the source of pollution is important as well. Fecal coliform bacteria can come from any warm-blooded animal. Sources could be leaking sewage pipes or septic systems. Pet, livestock and wild animals such as geese could also be the source. Addressing the specific source of bacteria can eliminate the problem.