Algae prompt Des Moines to switch drinking-water rivers
By JASON PULLIAM, jpulliam@dmreg.comSeptember 23, 2009, Des Moines Register
Record levels of potentially toxic algae in the Raccoon River have once again forced the Des Moines Water Works to draw from the Des Moines River to keep drinking water free of poor tastes, bad smells and health risks.
Levels of blue-green algae — also known as cyanobacteria — for the past month have been higher than those of last year, when readings were the highest Water Works CEO Randy Beavers had seen in his nearly 30 years of service.
Samples collected from the Raccoon in recent weeks have frequently exceeded 20,000 cyanobacteria cells per milliliter of river water — well beyond levels that can easily be treated for use as drinking water. Tests from this week showed levels above 60,000 — the highest waterworks employees have ever measured in the Raccoon River.
In some cases, cyanobacteria can release a toxin that can sicken or even kill animals and humans.
"That’s one of the reasons we go to the Des Moines River as another safety precaution should there be any unforeseen spikes in that toxin," Beavers said. "Fortunately, the toxin has been at very low concentrations."
Of further concern this year: Blue-green algae blooms have been more prevalent in the Des Moines River than in the past.
"It’s problematic for us when we are, in essence, reduced to one river source," Beavers said. "Our current treatment system just has a very difficult time handling the really high counts" of cyanobacteria. "From an infrastructure standpoint, we feel water quality should be sufficient that we could draw water from either river."
Water quality experts had wondered whether last year’s floods helped trigger the dramatic increase in cyanobacteria. However, the second year of high numbers has raised more questions about the causes and the solutions.
"The fact that this is not just a one-year event and the magnitude of the problem is greater this year than last gives me concerns that we’re heading in the wrong direction here," said Susan Heathcote, water program director for the Iowa Environmental Council. "We’re in a position where the Des Moines Water Works doesn’t have a lot of other options."
If current trends continue, the blue-green algae problem would complicate already complex pollution issues water works employees face, such as routinely treating for elevated levels of E. coli bacteria.
Toxins from the blue-green algae at extremely high levels can cause cramps, fever, vomiting, diarrhea or death. Lower levels commonly cause skin rashes.
Cyanobacteria readings over 100,000 are considered a health threat by the World Health Organization.
Beavers said the history of bacteria pollution coupled with the emergence of blue-green-algae problems underscores the need to improve conditions throughout the Raccoon and Des Moines river watersheds.
It would probably cost $1 million or more to upgrade treatment facilities to handle consistently elevated levels of cyanobacteria, Beavers said.
Instead, Beavers and others are hopeful improvements can be made throughout the 2.3-million-acre Raccoon River watershed to decrease the amount of nutrients such as nitrogen and phosphorus that feed the growth of algae blooms.
A group of ag retailers in central Iowa called Agriculture’s Clean Water Alliance formed in response to water quality concerns in the Raccoon River watershed. The group is working on ways to decrease nutrient runoff into the river and its tributaries.
Gulf of Mexico panel meeting in D.M.
The algae problems in the Raccoon and Des Moines rivers have similarities to runoff-related challenges in the Gulf of Mexico.
TASK FORCE: Today and Thursday, Des Moines will play host to the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force, comprising representatives from state and federal agencies who are working to reduce the nitrogen and phosphorus pollution linked to the "Dead Zone" in the Gulf of Mexico.
REMINDER: "The situation we are facing here in Des Moines with cyanobacteria blooms in the Raccoon and Des Moines River over the past few months reminds us that we must find ways to reduce the nutrient pollution in Iowa waters not just to benefit the Gulf of Mexico, but also to address serious nutrient pollution affecting Iowa waters," said Susan Heathcote, water program director for the Iowa Environmental Council.
For more information, visit www.tetratech-ffx.com/
http://www.desmoinesregister.