U.S. Water News Online
LAKE HAVASU CITY, Ariz. — The U.S. Bureau of Reclamation is beginning tests to see if a common bacteria can kill an invasive mussel threatening to spread across the West's waterways and damage systems that deliver water to millions of people in the region.
Reclamation scientist Fred Nibling said a preliminary test was done this summer at Davis Dam, on the Colorado River at Laughlin, Nev. Quagga mussels were exposed to a dead form of Pseudomonas fluorescens bacteria, a non-infectious microbe that occurs commonly in food, soil and water.
Reclamation decided to test the bacteria after a report by a researcher at the New York State Museum showed that both zebra and quagga mussels died after ingesting it.
“We are always looking for new, more effective techniques for managing mussels, and this one looks very safe and very promising,” Nibling said.
Quagga mussels were first found west of the Rockies in Lake Mead in January 2007. Since then, they've been spotted in canals in Phoenix and prompted boat inspections at lakes in California, Nevada and Utah to prevent their spread. They've become well established along the Colorado River's reservoirs and been found in California and Arizona.
The freshwater mollusks and their close cousins, zebra mussels, were accidentally introduced to the Great Lakes in the ballast of ships from Eastern Europe and the Ukraine. They are prolific reproducers and can plug pipes up to 12 inches in diameter and restrict flow in larger pipes. Their colonies can also cause corrosion in pipes and other underwater structures. Such as marinas and docks.
This summer's initial test involved exposing mussels to the bacteria in jars. Nibling said the next test would be conducted in a 10- to 20-gallon aquarium under conditions that simulate water flowing through the dam. The water used is disposed of through the dam's evaporation pond and never enters the river.
A third experiment will involve a domestic water intake line at the dam that's currently encrusted with 2 to 3 inches of mussels.
“We'll have a series of tests where we're going to be testing off-line, off the river, so we can have the data to where we can apply for the permits to test elsewhere,” Nibling said.
Reclamation could then do a larger scale test, possibly involving a marina. Open water tests would require Environmental Protection Agency approval and depend on the cost and availability of large quantities of the bacteria.
“Testing open water or testing a lake – that's a real unknown at this time,” Nibling said.
Before the product would be put into general use on the Colorado River, the bureau would meet with municipal public works and water authority officials, Nibling said.
“We want to make sure they're very comfortable and they have a chance to ask questions,” he said.
New York State Museum researcher Daniel Molloy confirmed the effects of Pseudomonas fluorescens on the mussels in 1998. The museum patented the invention, and in March announced that the Davis, Calif., firm Marrone Organic Innovations had been awarded a National Science Foundation grant to commercialize the technology.
According to Molloy's research, when mussels ingest a high density of a strain of the bacteria, a toxin inside the bacteria's cells destroys the creatures' digestive tract. Mussels readily feed on the bacteria, making it superior to a treatment like chlorine, which causes the mussels to close their feeding valves defensively.
The research also found the bacteria caused no mortality in fish and other desirable, freshwater organisms, including other shellfish.
Click here to subscribe to e-Water News Weekly!