U.S. Backpedaling on Agreement to Clean Up Selenium at Kesterson

The federal government is trying to back out of an agreement to clean up hazardous concentrations of selenium at Kesterson National Wildlife Refuge.

The state ordered the U.S. Bureau of Reclamation to remove more than 600,000 tons of selenium-contaminated earth from a dozen dry ponds on the 5,900 acre refuge, after scientists discovered that high levels of the toxic mineral were causing widespread death and deformity among birds nesting in the marshes of the central San Joaquin Valley site.

The deadline for the cleanup is the end of August, before the rainy season usually begins. But federal officials say they have new evidence showing that the state-ordered cleanup plan may not be a “safe or effective” way to get rid of the selenium contamination. They are asking the California Water Resources Control Board to reverse its 1987 order and consider alternative solutions, a process that could delay cleanup for at least a year or two.

The federal request was made during a two-day state-board hearing last week in Sacramento. A decision by the board is not expected until mid-June.

The state order was issued after scientists discovered that selenium was contaminating underground aquifers in and around the 5,900-acre refuge. The cleanup plan calls for the contaminated soil to be piled in a 45-acre mound somewhere on the refuge.

The 25-foot-high mound would be sealed to prevent leakage, bureau officials said. The initial cost would be more than $8 million, but maintenance of the disposal site could run the costs considerably higher over the years, experts said.

As a substitute, the bureau is offering to make Kesterson unattractive to wildlife so that the birds will not feed on the selenium-contaminated vegetation. Its actions would include plowing the marshland or spraying herbicides to kill the vegetation. Bureau officials would also spray pesticides on ponds that would form after rains, destroying insects and plants contaminated by selenium that might be consumed by birds.

This, bureau officials say, would give them more time to find alternative ways to solve this toxic dilemma. The officials told the state board that UC Riverside soil scientists are experimenting with ways of getting rid of the selenium problem naturally.

The experimental process involves soil microbes that can ingest selenium and convert it to harmless gas that disappears in the atmosphere, said Dave Houston, the bureau’s Western regional director.

“This has great promise,” Houston said, explaining that by adding manure and citrus hulls to “feed” the microbes, the scientists have stimulated the natural processes that remove selenium from the soil, releasing it into the air.

The bureau’s new proposal is vigorously opposed by environmentalists who demand that the cleanup be completed on schedule.

Proposed Alternative

“The bureau’s proposed alternative is a technically and legally deficient plan that will not provide a cleanup in the foreseeable future,” said Natural Resources Defense Council scientist Laura King. The Environmental Defense Fund’s Terry F. Young agreed, contending that the bureau’s new proposal “will result in further damage to wildlife” because it leaves selenium in place while the new techniques are tested.

The selenium problem is linked to the government irrigation projects that deliver water to the once-arid plains along the west side of the Central Valley.

Selenium appears naturally in these soils and, in tiny amounts, the mineral moves naturally up into the food chain, where it becomes a part of the wildlife diet. However, when farmers in the area irrigate their lands, the excess water draining through the soil collects selenium, carrying off high concentrations of the toxic mineral.

For years, the bureau collected the drain water and used it to flood the Kesterson marshes and ponds. When the dying and deformed birds signaled a major pollution problem was in the making, the drains were plugged and the Kesterson ponds were drained.

Leaking Into Aquifers

Last spring, the state ordered the site cleaned up because selenium was leaking into the aquifers. “Although we disagreed with the board that the excavation and on-site disposal method was the best way to proceed . . . our overriding concern was to correct the problem and not waste time arguing,” Robert Kallman, special assistant to Interior Secretary Donald Hodel, told the board. The Bureau of Reclamation is a part of the Interior Department.

“Our scientists now believe that the planned excavation will not achieve cleanup . . . and the post-excavation effects may complicate the process of completing an effective cleanup,” Kallman said. He said new research has come up with “promising alternative cleanup strategies.”

Testifying before the board, a dozen bureau experts said they tested the on-site disposal method and found that removing six inches of contaminated soil from the dried-out ponds would not solve the problem because more selenium was lurking below the surface. The additional selenium concentrations have been found in the water trapped in the porous layer of soil that extends 10 feet or more below the ponds.

During the wet season, the shallow water tables flood to the surface and bring high concentrations of selenium, recontaminating the surface water and wildlife habitat, the experts testified.

This new finding means that the cleanup process might have to be repeated and the total cost of trying to keep a selenium-free environment could reach $100 million, bureau officials told the state board.

“The on-site cleanup just does not make sense--it will not work,” Houston said. He contends that the new bureau plan would keep the Kesterson environment “benign,” by keeping the wildlife away while scientists seek new solutions to the problem. He could not say how long it would be before the microbiological experiments would be completed and full-scale application of this technique could be used.