As the 4th of July weekend approaches, families with recreation plans on Lake of the Ozarks should be mindful of new test results that show elevated levels of a potentially harmful bacteria in parts of the lake.
The Missouri Department of Natural Resources on Tuesday reported that five of 53 samples of lake water have E. coli bacteria in excess of the standard used for swimming and other whole body contact. The samples, taken on June 16, were the first taken from sites between the Lake of the Ozarks Community Bridge and mile marker 30 near Osage Beach.
One sample at Cove 048, near mile marker 21, found E. coli present at 1,553.1 colonies per 100 milliliters, more than 12 times the state standard for swimming and aquatic recreation. The state water quality standard for recreational water bodies is a geometric mean of 126 E. coli colonies per 100 milliliters. This mean is a statistical method used to reduce the impact of higher and lower values because of different results within a given sampling area.
Other sites with E. coli levels above the standard were Woods Hollow near mile-marker 22 and Salt Hollow near mile-marker 21, both near Osage Beach.
Larry Archer, spokesman for the department, said one of the first questions people ask about elevated levels of the bacteria is whether the water is safe. He said that’s for individuals to decide.
“We do the testing and provide the information so individuals can make their own decisions,” Archer said. “If they are concerned, they should check with their local health department to become better informed.”
He said the department tells people to be careful not to ingest the water when swimming in the lake.
A call on Tuesday to the Lake of the Ozarks Convention and Visitors Bureau was not immediately returned.
E. coli is most commonly found in the intestines and feces of healthy warm-blooded animals and humans, according to a fact sheet found on the natural resources department’s Web site. The bacteria can cause gastrointestinal illness, especially in at-risk groups.
“It’s not like a freight train coming at you,” Archer said. “If you’re young, you might be tolerant. But if you’re part of an at-risk group such as the very young, elderly or have an autoimmune disorder you probably want to be more careful.”
The Department of Natural Resources’ Southwest Regional Office will be investigating the possible causes of contamination. Archer said the contamination may be from septic systems, other sewage treatment facilities or from wildlife. Archer said the regional office has a list of all the permanent facilities that operate under a department water permit and regular inspections will be conducted on those facilities.
“The goal is to figure out if this is a man-made problem,” Archer said.
The most recently sampled sites will be tested again in August and October.
“We do that so we can get a track-record of these locations,” Archer said. “We’re looking for long-term trends.”
The monthly sampling from May to October is the result of a partnership between the Department of Natural Resources, the Department of Conservation, AmerenUE and the Lake of the Ozarks Watershed Alliance. Ameren is paying $15,000 per year for the five-year study. When completed, the water testing will include coves from Bagnell Dam to Truman Dam.