More Tests Will Assess Danger Posed By Legionella Bacteria

Irvine Ranch Water District officials Tuesday called for more testing to determine whether the legionella bacteria recently detected in irrigation waste water presented any danger to county residents.

The bacteria linked to the cause of Legionnaire’s disease was found in water samples taken from the Orange County Water District and the Irvine Ranch Water District as part of research performed by the Orange County Sanitation Districts.

Those findings were to be presented this week to a convention of the American Society of Microbiologists in Las Vegas.

Ken Thompson, the Irvine district’s water quality manager, said the district has been using reclaimed water for irrigation purposes since 1967 and has “never had an illness caused by the highly treated water.”

“It is important to note that legionella bacteria is a background bacteria found throughout the environment,” Thompson said. “In this instance, we don’t know if the bacteria is alive or not and whether it’s actually the individual species that can be harmful.”

Dr. Hildy Meyers, the county’s epidemiologist, has also called for additional testing of the treated waste water, which has been used to irrigate Mile Square Regional Park in Fountain Valley.

Meyers did not know whether the sanitation agency findings were cause for concern, since the research did not address whether people could be infected by the bacteria found in the water.

Only one case of Legionnaire’s disease has been reported in Orange County this year, Meyers said.

“Legionella is an organism that can be found anywhere, not just in reclaimed water,” Thompson said. “The concentrations in Irvine water noted in the study are far below levels known to cause illness in previous case studies. (Irvine) samples actually showed the lowest levels of legionella bacteria of any noted in the study.”

Legionnaire’s disease was discovered nearly two decades when it struck an American Legion convention in Philadelphia. Legionella bacteria grow in water and can be spread through the air by large air-conditioning systems, decorative fountains or other water systems.

The bacteria may cause a pneumonia-like illness that can be fatal in its most advanced stages.

The sanitation agency research, partially funded by National Water Research Institute, has been the subject of much controversy within the agency itself. Margaret H. Nellor, the agency’s acting director of technical services, has said the report contained “numerous errors” and urged that it should be labeled only as “preliminary.”