There’s No Way Yet to Reach Level Sought for Chromium 6, Study Says

As Los Angeles and other cities consider the costs of tougher drinking-water standards for chromium 6, a draft report says there is no proven treatment for reducing the suspected carcinogen to the trace levels recommended by a state health agency for optimum safety.

Los Angeles, Glendale, Burbank and San Fernando would have to spend hundreds of thousands of dollars in research and development to test water treatment systems to ensure that they can reduce chromium 6 to such low levels, according to a draft report prepared for the cities.

Such research would be a necessary first step before the construction of multimillion-dollar treatment plants, said Michael Maguire, the environmental consultant who wrote the draft report.

“We don’t know if we can achieve those low concentrations because all of the current technology is shooting to meet the existing standard of 50 parts per billion,” Maguire said.

Santa Monica-based Maguire Environmental Consulting Inc. was hired to help Los Angeles and the other cities assess water treatment options and costs in a first step toward building treatment plants to reduce chromium 6 in drinking-water supplies.

Anticipating tougher state standards, officials in the four cities--among the first to express concern over chromium 6 in drinking water--are trying to assess how they will comply if forced to reduce chromium 6 levels.

The report will be used by the cities to plot their courses of action in determining whether to invest millions of dollars to build treatment plants for water supplies that already meet all current drinking-water standards.

Pankaj Parekh, manager of regulatory compliance for the Los Angeles Department of Water and Power, said his agency is taking a cautious approach, given the uncertainties.

“We don’t want to be a guinea pig for technologies that are not yet proven,” Parekh said. “We would rather invest in something that has a track record.”

The state Office of Environmental Health Hazards Assessment has called for slashing the chromium standard in drinking water from the current 50 parts per billion to 2.5 ppb--which assumes a chromium 6 level of 0.2 ppb. There is no separate standard for chromium 6.

Lawmakers are considering legislation to force the state Department of Health Services to reconsider its current standard for chromium and develop a separate one for chromium 6.

Although the health hazards office has set a public health goal for chromium to reduce levels of the metal’s toxic byproduct, chromium 6, federal, state and county health officials have said that evidence suggesting chromium 6 is a carcinogen is inconclusive.

Without an existing treatment model, the cities will have to develop their own methods for reducing chromium 6 contamination in water from the polluted San Fernando Valley aquifer.

A byproduct of industrial manufacturing, chromium 6 has been found at levels as high as 30 ppb in the San Fernando Valley aquifer, which supplies Los Angeles and other cities with drinking water.

Treatment systems now in use--including facilities in Ontario and La Puente--reduce overall chromium to the current state limit of 50 parts per billion or lower, Maguire said.

To further reduce those contamination levels, the cities will have to spend hundreds of thousands of dollars in research to build scaled-down models of full-size treatment plants for testing to ensure that their goals can be achieved, Maguire said. He is optimistic.

“Our expert judgment is that it looks like it would work,” Maguire said.

But it would be costly. Sen. Jack Scott (D-Altadena) has introduced legislation to provide $15 million to the state Department of Health Services for research and the development of technology to reduce chromium 6 contamination to trace levels.

Don Froelich, Glendale’s Water Services administrator, said state and federal governments should help pay for the research.

“It’s something that will benefit California and other communities that have chromium in their water supplies,” he said.

Under state law, the health department must consider technical feasibility and treatment costs in deciding whether to tighten drinking-water standards.

Dr. David Spath, drinking-water chief for Health Services, said the state has not yet begun those evaluations. Spath said his office is evaluating the extent of chromium 6 contamination in the state’s drinking-water supplies and will decide within the next year or two whether to toughen the standard for chromium or to set a new one for chromium 6.

Besides the unproven treatment technology, Spath said, reliable methods also are needed to test for chromium 6 at levels as low as 0.2 ppb.

“We would not feel comfortable in telling water companies they have to test down to that level,” Spath said.

Chromium 6 can be reduced in water by ion exchange or the more costly reverse osmosis method. In one Burbank scenario, Maguire estimates that reverse osmosis treatment to lower chromium 6 levels to 0.2 ppb would cost $580 per acre-foot of water--$51 more than the cost of buying imported water from the Metropolitan Water District.

Ion exchange is less expensive and removes other contaminants such as nitrates, arsenic and perchlorates, which also diminish drinking-water quality.

Maguire also warned of the potentially high cost of disposing of chromium 6-tainted waste from any treatment plant.