Spread of Pollution Spurs EPA Water Study

The U.S. Environmental Protection Agency, spurred by concern that water contamination in the San Gabriel Valley has spread to Whittier Narrows and could flow into the central Los Angeles water basin, has earmarked $3.85 million to investigate the potentially serious problem.

The agency also will use $1.95 million from its Superfund earmarked to combat severe contamination to construct treatment plants in north El Monte, where contaminants have already been identified in the water system.

Trying to determine how pollutants are getting to Whittier Narrows and pinpointing their source will involve an investigation of the entire San Gabriel Valley ground-water basin, said Neil Ziemba, an EPA environmental engineer who is directing the work here.

The basin is bordered by the San Gabriel Mountains on the north, the Puente Valley on the east, Alhambra on the west and Whittier Narrows on the south,

The 400 wells in the 170-square-mile area serve nearly 1 million people.

“Our work now is to come up with an overall approach for the valley because the site is so large,” Ziemba said. “We know the contaminants are migrating to Whittier Narrows but we don’t know where they are coming from.

“We have not identified the pollutants, their cause or their extent. But we are concerned that they could migrate through the Whittier Narrows to the Los Angeles basin, where they would be very difficult to contain.”

Information Under Review

The EPA and other agencies involved, including the state and county departments of health services and the Upper San Gabriel Valley Water District, are reviewing current data, Ziemba said.

The early focus will be on Whittier Narrows, where the pollutants were discovered in 1985 through well sampling and an analysis of ground-water flow in the area, he said.

Field work, starting with the periodic monitoring of wells, is expected to begin in two to three weeks. In early June, soil gas, which may indicate the presence of contaminated water below, will be sampled, Ziemba said.

The next step will be a sampling of surface water in San Jose Creek in the Industry area and the lower San Gabriel River.