Bacteria sample sites in the James River Basin

What are bacteria?
Bacteria are microscopic organisms that with many different types of species, shapes and characteristics.  Bacteria have been negatively associated with infections from tuberculosis to strep throat, and many illnesses today are related to the presence of harmful bacteria.  However, not all bacteria are harmful.  Bacteria in the environment help to cycle nutrients such as nitrogen.  Many bacteria are beneficial to humans—for instance allow fermentation cheese and yogurt.  They inhabit nearly all environments, from hot springs to cold artic habitats.  In humans, bacteria normally reside in many body parts, including the skin and the digestive tract.  In rivers and lakes, bacteria are most common on the banks and the bottom.  Bacteria are usually in lower numbers in the open waters of rivers and lakes.

What is E.coli?
E.coli is a shorthand abbreviation for the bacteria species Escherichia coli.   E. coli belongs to a group of bacteria known as coliforms. E. coli is used to test for harmful bacteria because it is found in the waste materials of animals and humans. Because of this fact, the presence of E.coli in water suggests that there may be other intestinal bacteria in the water that could cause sickness.  E.coli is also used to test for fecal contamination (intestinal bacteria) because it is usually not found in uncontaminated water.  E.coli is used in tests because of the ease of identification.  Because E.coli do not live long in water, presence of E.coli indicates that contamination is recent and other fecal bacteria may be present in the water at that time. Many E.coli strains will not make you sick, however, the strain E.coli 0157:H7 is known to cause illnesses in humans.

Why should you be concerned about bacteria in our local waters?
If water contains bacteria from fecal origins such as E.coli, the water is unsafe to drink and activities where water may be ingested should also be avoided. If someone does ingest water contaminated with harmful bacteria such as E.coli, they could have ailments such as typhoid fever, cholera, and bacillary dysentery.  Likely ailments resulting from the ingestion of harmful bacteria in water include acute dehydrating diarrhea, prolonged fever and abdominal troubles, acute bloody diarrhea, and chronic diarrhea.  Avoid eating fish from these waters.

What level of E.coli is unsafe?
The Environmental Protection Agency has established a safety level of 235 colonies of E.coli per 100mL of water.  Samples with readings above this level are unsafe to swim in and to drink. Samples with readings below this level are considered safe for “full body contact”.  Even if below this safety limit, as a usual rule, water from local lakes and streams should not be ingested on purpose.  Drinking water from the city is monitored regularly for E.coli and is safe to drink. The level of 235 colonies of E.coli per 100 mL of water sample means that for every 1,000 swimmers, about eight of them will be infected with waterborne illnesses. 

How do agencies measure the bacteria levels in water?
A number of different tests can be used to determine how much bacteria is in the water. Usually, a sample is collected (100mL in size) and this sample is then taken back to a laboratory where the analysis is conducted.

In one type of test, the 100mL sample is poured through a paper filter that sucks the water through, leaving the bacteria on the top of the paper filter.  This filter is then placed in a container that has enough nutrients for the bacteria to grow. The container is incubated, and then the number of bacteria colonies are counted.

Another test called the Colilert defined substrate test is used to detect E.coli.   In this test, the water sample is put into certain nutrients and chemical agents.  If coliforms are present, the sample will turn yellow and the number of yellow colonies can be counted. The sample can also be looked at under special UV lights to see if the sample is fluorescent, which indicates that E.coli are present. This is the method used by local health departments.  The maximum number of colonies that can be counted with this method is 2,419.  Therefore, values of 2,419 colonies indicate that levels are actually higher than this number.

Where are the bacteria coming from?
Bacteria such as E.coli live in the intestines of animals. Because of this, common sources of E.coli in waters are animal waste runoff and sewage.  According to the Greene County Health Department, E.coli in recreational water can come from the following sources:

• Urban and agricultural runoff
• Malfunctioning onsite sewage treatment systems (septic tanks, lagoons, etc.)
• Sewer overflows (both sanitary and combined sewers),
• Wild and domestic animal waste
• Human fecal accidents in the water” (Goddard 2002).

Sometimes, E.coli/bacteria will increase in a body of water after a rainstorm because the rainwater washes animal waste from the ground into the water.  Other spikes in the data could result from events described in the bullets above.

Many bacteria are common to waters.  Bacteria live on the surfaces of plants and aquatic animal as well as in the soil substrate of lakes and rivers. These bacteria are important to the functioning of the river ecosystem.

How can we determine where the bacteria have come from?
One way to see where the bacteria are coming from is to take water samples at different locations on a river/creek.  For instance, if you take a water sample above (upstream) a suspected source (a leaking septic tank for example) and then take a water sample below this site, you can compare the levels from both samples.  If the value of bacteria is higher below the site (downstream), then you can infer that the septic tank was a source of the elevated bacteria levels. 

DNA analysis can also be done to determine where the bacteria have come from.  According to the University of Missouri’s FAPRI Environmental Report, “DNA source tracking techniques are used to obtain patterns of the coliform colonies and compare them to patterns of known species including humans, cattle, poultry, dogs, horses, hogs, and wildlife” (Shoal Creek Watershed Project 2002).

Solutions to Bacteria in Water
This section discusses what both the local agencies are already doing and what the individual citizen can do to decrease harmful bacteria in local waters. A list of important contact numbers is provided at the end of this section.  If you need more information concerning these issues, or if you want to find out about current bacteria levels, feel free to call these local agencies. 

What are local agencies/authorities doing to prevent bacteria contamination in our local waters?
Locally, the Christian County Health Department, the Greene County Health Department, and the Stone County Health Department are monitoring specific river sites.  These health departments measure the water for bacteria regularly during the summer months because this is the time when people will be recreating in the water.  Most of the health departments begin their monitoring for bacteria in mid-May and continue through August.  If an event occurs such as a wastewater overflow, the health department will then start monitoring the river where the contamination occurred.  The health departments also will issue a “whole body contact” ban on a particular river/creek if the E. coli levels are higher than the 235 colonies/100 mL safety limit (Goddard 2002).  This means that swimming is not allowed and other activities like fishing or canoeing should be done cautiously.