This article has been amended, see note below for details.
After spending more than 10 years and roughly $9 million, engineers testing two high-tech methods for removing chromium 6 from groundwater say neither method can reliably bring levels of the cancer-causing contaminant down to the point where it would hit a state public health goal.
In 2011, the California Office of Environmental Health Hazard Assessmentset set a goal of drastically reducing the amount of chromium 6 — the contaminant brought to notoriety by the 2000 film “Erin Brokovich” — in the water supply.
Research on developing new, cost-effective methods for ridding groundwater of chromium 6 — which has been ongoing in Glendale for more than a decade — will play a key role in determining how far agencies will be forced to go in removing the contaminant from water supplies.
Glendale Water & Power, which has been grappling with vast swaths of underground aquifers tainted with chromium 6 by a long-gone aerospace manufacturing industry, has been the lead agency, using state grants and money from polluters to fund the research.
The two methods have proven effective in stripping tainted water of the chromium, but Nicole Blute, senior associate at Hazen & Sawyer, an environmental engineering firm hired by the city to conduct the research, said “this research really demonstrates that we could not get to the public health goal.”
And even though the test results show utilities can get close to the goal, it could cost tens of millions of dollars to do so over the span of 20 years, according to a final report researchers submitted to the state last week.
The cost and feasibility report will play an important role as state officials set a new legal limit for chromium 6.
By law, state officials must get the limit — planned to be released by July 2015 — as close as economically feasible to the public health goal of .02 parts per billion. Currently, the maximum contaminant level for total chromium in California is 50 parts per billion.
The state Department of Public Health is in the process of reviewing Glendale's report and plans to respond with comments, said agency spokeswoman Anita Gore.
Glendale and other San Fernando cities have been grappling with water contamination. The city distributes water with chromium levels of 5 parts per billion or less by blending contaminated groundwater with clean imports from the Metropolitan Water District of Southern California.
But the cost of Metro water has pushed Glendale Water & Power to ratchet up its own rates. That, in turn, has fueled efforts to improve local well systems in order to reduce the utility's reliability on imports by pumping more from underground aquifers.
According to the research report, it would be cheaper per acre foot — roughly 325,900 gallons — for a utility the size of Glendale Water & Power to use the tested removal methods than to pay for imported water if local wells are used year round.
One method, which uses a resin to remove chromium 6, could cost about $500 per acre foot for treatment compared to the $847 per acre foot Glendale pays for imported water.
But the estimates reflect the contaminant at 5 parts per billion, far from the public health goal, and use numbers spread out over a 20-year lifespan.
The lower the state contaminant limit, the higher potential costs for utilities statewide — and ratepayers can expect to pay for the increase.
“This will have an impact to the rate that any entity charges,” Ramon Abueg, assistant general manager for Glendale Water & Power, said at a City Hall meeting this week.
Steve Zurn, the utility's general manager, said Glendale may ask companies who first contaminated the water decades ago to foot the bill.
The upfront costs of installing the cleansing systems could be a hindrance to utilities that have difficulties raising capital, Blute said.
Glendale has two systems that can reduce the contaminant's levels, but one, a labor-intensive method, was mothballed last year after researchers finished tests.
Installing the resin removal method in a large system — one that can handle a population of 10,000 to 100,000 — could cost $27 million to install, operate and maintain over 20 years, according to the report.
While the final report is complete, researchers plan to continue working, sending a supplemental report to state officials by the end of the year.
The research has sparked other chromium removal studies, but Glendale has been a pioneer.
“Glendale is the nationwide leader,” Blute said.
[For the Record, March 11: An earlier version of this story incorrectly referred to the California Department of Public Health setting the public health goal.]