|Nebraska Department of Environmental Quality|
Weekly Sampling Measures Blue-Green Algae Toxins,
Bacteria at Nebraska Lakes
During the summer months, Nebraska’s lakes are a popular destination for activities such as boating, water skiing and swimming. In an effort to provide the public with information about current water quality and potential risks, the Nebraska Department of Environmental Quality conducts weekly sampling at public beaches from the beginning of May until the end of September and posts the information on the agency web site.
NDEQ and its partners (the Nebraska Game and Parks Commission, Natural Resources Districts and other entities) obtain their weekly samples at publicly-owned and operated swimming beaches and public lakes that allow power boating. In 2008, 51 swimming beaches at 47 lakes were included in the network.
What is monitored at the beaches?
In 2005, NDEQ combined the monitoring of two aspects of water quality – Microcystin (toxic blue-green algae) and E. coli bacteria -- into a single statewide monitoring network. Samples that are collected early in the week are typically posted on the web site by Friday morning. The public can access the weekly results by going to: Toxic Blue-Green Algae and Bacteria Sampling Results.
Toxic blue-green algae – potential effects and the Health Alert system
Microcystin is a toxin that is released when certain strains of blue-green algae die and break down. Blue-green algae look like thick green paint or oil floating on the surface of a lake and often exhibit an offensive odor. If concentrations of the toxin are high in a lake, it can cause a number of unpleasant health effects to recreational users including; skin rashes, lesions, and blisters. If swallowed, the toxin can cause flu-like symptoms such as headaches, nausea, diarrhea or vomiting.
When levels of microcystin exceed 20 micrograms per liter, the Departments of Environmental Quality and Heath and Human Services jointly issue a Health Alert. During a Health Alert at a public lake, signs are posted advising the public to use caution. Affected swimming beaches will be closed. Boating and other recreational activities will be allowed, but the public will be advised to avoid full body contact with the water where one would become submerged, and to particularly avoid drinking the water.
Click here for more information about Health Alerts and toxic algae
E. coli bacteria – potential effects and how the data is used
The state measures the levels of E. coli bacteria in state recreational lakes because high levels can be an indicator of pathogens that can cause illnesses. Swallowing water containing these types of bacteria can cause nausea and other stomach flu-like symptoms.
E. coli bacteria is considered to be at high levels when the counts are greater than 235 counts of bacteria per 100 milliliters of water. The state does not issue Health Alerts regarding high bacteria at lakes. Instead, weekly bacteria information is posted on the web site, so that the public can decide whether or not to use the lake. The state provides the following guidelines to consider regarding bacteria:
- Avoid situations which could cause you to swallow lake water
- When levels are high, shower after coming in contact with the water
- If you have been in contact with lake water, wash hands before eating
- Use particular caution after a heavy rain, because runoff can cause higher levels of bacteria
Click here for more information about bacteria and its potential health effects.
In 2008, the Beach Monitoring program collected a total of 1,022 microcystin samples and 957 E. coli bacteria samples. Often bacteria present a problem early in the recreation season as a result of rain and run-off from land, whereas blue-green algae (microcystin) impacts are more likely to occur later in the summer, after lake water has warmed up and algae have had time to grow. The data indicated:
- Microcystin (toxic blue-green algae) sampling in 2008 resulted in Health Alerts being issued at eight lakes with the periods of time beached were closed spanning from two to eleven weeks. Of the 1,022 samples that were collected, 34 (3%) exceeded the health alert level of 20 parts per billion. From 2005 through 2008, NDEQ collected more than 3,000 microcystin samples from 58 lakes across the state. Seventeen (29%) of these lakes had at least one sample with concentrations above 20 parts per billion.
- Of the 957 bacteria samples taken and analyzed in 2008, 82, or 9%, exceeded 235 counts per 100 milliliters of water. The total number of lakes in the network that exhibited high levels of E. coli varied from zero to six in any given week. During the month of June, 23 samples exceeded 235, while in August, only four samples exceeded the 235 count limit.
For more information
To view the weekly readings for toxic algae and bacteria, go to: http://www.deq.state.ne.us/Beaches.nsf/LakeSampling09.
If you have questions about the sampling program at Nebraska public lakes or you suspect a public lake is experiencing a water quality problem, contact NDEQ at (402) 471-2186 and ask to speak to someone in the Surface Water Unit or the Public Information Office.
If you have questions regarding sampling of a private lake, contact the University of Nebraska Water Quality Extension Program at (402) 472-7783, or (402) 472-8190.
If you experience health symptoms, notify your physician, and also report it to the Nebraska Department of Health and Human Services at (402) 471-8880. You can also contact the Nebraska Regional Poison Center at
800-222-1222 for more information.
Nebraska Department of Environmental Quality
1200 "N" Street, Suite 400
P.O. Box 98922
Lincoln, Nebraska 68509