September 13, 2017 | Jim Townsend
E. coli bacteria levels in Clear Lake have fallen to levels well below federal safety thresholds, says a University of Houston-Clear Lake microbiologist who has been testing the waters since Tropical Storm Harvey flooding.
The Environmental Protection Agency sets standards of acceptable levels of fecal indicator bacteria in fresh waterways. Escherichia coli – E. coli for short – and other coliform bacteria are produced from the feces of warm-blooded animals, including humans.
Under the direction of Assistant Professor of Microbiology Michael LaMontagne, students in his research-intensive Environmental Microbiology class collected samples from six locations around Clear Lake. In those samples, E. coli bacteria ranged from 488 to 1,733 most probable number of colony-forming units per 100 milliliters. Colony-forming units, or CFUs, estimate the number of viable bacteria cells that have the ability to multiply. EPA’s statistical threshold value for recreational freshwater is 320 cfu/100 mL.
LaMontagne’s students collected new samples from the same sites on Sept. 8. The number of E. coli cells fell levels fell to levels that are considered safe for recreational use, ranging from a low of 4 to 69 cfu/100 mL.
“Things are looking better,” LaMontagne said.
However, he emphasized the value of continued research. “Rising sea levels and warming tropical waters may double the frequency of coastal flooding in the next few decades. We need to develop protocols to both assess the health risks associated with these events and implement long-term monitoring and rapid-response protocols.”
LaMontagne collaborating on the project with George Guillen, associate professor of biology and environmental science at UHCL and executive director of the Environmental Institute of Houston. Other collaborators include Associate Professor Terry Gentry at Texas A&M University and Associate Professor the Michael Allen at the University of North Texas Health Science Center.