Source of Chromium Is Critical

There are still more questions than answers about chromium 6 in local water supplies. Scientists disagree on what level is considered safe, engineers on whether it can be removed--and at what cost.

In the first weekly test requested by the city of Thousand Oaks, Calleguas Municipal Water District found its water to contain a tiny fraction of state-mandated maximum. Calleguas serves Thousands Oaks and much of Ventura County.

But Mel Blevins, the court-appointed watermaster who oversees ground water pumping rights for the upper Los Angeles River basin, is making progress on answering one crucial question: How did it get there?

Chromium 6 is a toxic byproduct of chemical reactions involving chromium, a metallic element found in nature and used in industries ranging from aircraft manufacturing to electroplating.

Last year Blevins unearthed city records from the 1940s and 1950s showing high levels of chromium 6 in storm drains. Water experts speculate that some of that runoff may have seeped into the San Fernando Valley aquifer through a 7-mile stretch of the Los Angeles River near Glendale that is not lined with concrete.

But because the city tested only storm drains, the old records did not tie discharges to specific industrial sites.

Now Blevins believes he has found an even more direct route to the water table--and a specific company. State and county records show that Lockheed Martin Corp. dug wells in the 1940s to draw hundreds of millions of gallons from the aquifer for its air-conditioning system, then discharged the water, by then laced with chromium 6, through separate return wells.

A company spokeswoman confirmed that Lockheed Martin used chromium 6 as a rust inhibitor until 1966 in water circulated through cooling towers at its former Burbank defense plant, but said there is no evidence that the discharged water got back into the aquifer.

Blevins’ investigation will continue; he intends to take testimony from retired water quality workers. In addition, the Los Angeles Regional Water Quality Board, the agency that governs drinking water standards in Los Angeles and Ventura counties, is surveying about 150 industrial sites in the East Valley about their use of chromium 6.

Pinpointing the source of chromium 6 makes it possible to determine whether the metal is still leaching into the water table and therefore may help prevent further contamination.

It also ensures that whoever is responsible for the pollution pays to clean it up and to install, if necessary, the costly technology needed to remove the chromium 6 from the ground water.

Although toxicologists disagree over the danger posed by the fairly low concentrations found around Los Angeles so far, they agree that the uncertainties dictate doing whatever possible to get chromium 6 out of drinking water.

Only by finding the source can the public recoup cleanup costs. And only by tracing the history will the public and policymakers know how bad the problem could get and how bad it may have been in previous decades.