Development of the so-called Public Health Goal for chromium 6 is in its final stages, and water officials have declined to venture a concrete guess, but the acceptable level “could very well be a fairly low number, less than the five [parts per billion],” said Dan Askenaizer, senior environmental program specialist for Glendale Water & Power.
Chromium 6, or hexavalent chromium, has been shown to cause cancer when inhaled. A National Institutes of Health study last year found chromium 6 caused cancer in lab animals when ingested.
A state Environmental Protection Agency limit based on the Public Health Goal advisory, which will take several more years to develop, has local water officials working to reduce chromium 6 levels before they face environmental penalties.
There is currently no regulatory limit for the toxic element in water supplies, just a combined limit of 50 parts per billion for all types of chromium, according to the EPA.
Two Glendale wells have been found to be contaminated with chromium 6 beyond that threshold, city officials say. But by the time the water reaches the Glendale Water Treatment Plant, the average contamination rate is between 10 and 12 parts per billion, according to the report. And after that water is blended with untainted imports, the contamination level citywide drops to below five parts per billion, Askenaizer said.
A $2-million state grant was approved in March to help fund an ongoing, cross-jurisdictional pilot study of two chromium filtering systems at Glendale’s treatment plant. At the same time, cleanup efforts continue through the San Fernando Valley basin in an attempt to halt the spread of chromium 6 plumes underground.
