SUNDAY DEC 16, 2007 (Foodconsumer.org) -- Two reservoirs that supply drinking water to part of the city of Los Angeles have been shut down due to contamination of a cancer-causing agent known as bromate, which results from a sunlight and chlorine reaction in the case, news media reported.

The tainted open-air Elysian and Silver Lake reservoirs will be drained early next year, The Los Angeles Department of Water and Power spokesman Joseph Ramallo was cited as saying in a statement.  

The decontamination process is expected to take 3 to 4 months and will result in the discharge of over 600 million gallons of contaminated water.

The reservoirs of concern account for only less than 1 percent of the city's drinking water, meaning that it won’t cause any significant impact on the serving of drinking water in the city.   Los Angeles uses 107 tanks and reservoirs along the Los Angeles Aqueduct and in the city.

High levels of bromate were detected in a testing performed in early October by a commercial customer although the contaminant is not subject to routine testing.   After the discovery was confirmed, the utility service immediately removed the reservoirs from service and notified the state Department of Public Health.

Officials said the level of the contaminant in the reservoirs does not impose an immediate risk and any toxicity due to ingestion of the pollutant will only show up after a long period of using the tainted water.