Agency Releases Wildlife Refuge’s Cleanup Options

The U.S. Bureau of Reclamation on Tuesday said it is considering a $1.1-million plan to spray herbicides on vegetation and then set it on fire as a means of beginning an interim cleanup of the selenium-contaminated Kesterson National Wildlife Refuge near Los Banos.

But, bureau spokesman Jerry King emphasized in a telephone interview from his Sacramento office, the plan is only one of several that the bureau is considering as part of its effort to protect waterfowl and other wildlife while a long-range solution to the Kesterson contamination problem is developed.

The other options, none of which would require anything as drastic as herbicide spraying or burning, emerged Tuesday at a meeting of various officials representing San Joaquin Valley communities and the state and federal governments.

The Kesterson refuge, considered one of the worst cases of selenium contamination in the country, has become the focus of national and international interest. Selenium, a trace material occurring naturally in soil, is necessary to growth, but when it reaches the high levels found at Kesterson, it becomes a powerful mutagen and killer. Severe birth deformities have been found in ducks and other waterfowl, and creatures such as frogs are dying.

Kesterson lies directly beneath the Pacific Flyway, which is one of the principal routes taken by migrating waterfowl between Canada and Mexico each year. The United States, along with Canada and Mexico, is a signatory to the 1918 Migratory Bird Treaty that pledges the three nations to protecting migratory birds.

Last month, the Department of the Interior said it would immediately close the refuge to selenium-laden agricultural waste water and cease delivering irrigation water to more that 42,000 acres of farmland.

Since then, a compromise has been reached allowing farmers to receive their water this year. But the federal government has continued to seek ways to begin the cleanup of the refuge and still says it will close the refuge to farm wastewater by June 30, 1986.

The plan to spray herbicides on the contaminated vegetation immediately drew protests at Tuesday’s meeting.

Scientists with the U.S. Geological Survey warned that removing the vegetation might remove an important natural filtering mechanism that reduces the amount of selenium seeping into the shallow ground water aquifers directly beneath the contaminated ponds.

“It’s a concern,” said Marc Sylvester, toxic waste coordinator with the survey’s Western Region office in Menlo Park.

“We don’t know what the impact will be on the surface or subsurface water systems in terms of the hydrology and geochemistry. We do know that if you do anything, it will change that system. There is a potential that if you scrape off the soil and de-water the ponds and remove a protective layer of soil that that could result in greater seepage, particularly if you filled the ponds back up to their capacity.”

In addition, Merced County officials and others objected to burning the vegetation because of fears over the selenium being put into the air.

The spraying plan calls for using the herbicides Rodeo, diquat and dalapon--all effective at killing a wide range of vegetation. The burning would then take place after the vegetation had been dried. King, the bureau spokesman, also said consideration was being given to lacing the ponds with rotenone to kill the fish.

“The idea is to remove vegetation in the waterfowl food chain as a means of enhancing the hazing program,” King said. “It’s a very short-term undertaking, perhaps over the next 12 to 18 months, if we do it. The biggest problem is that the vegetation provides both a habitat and food source.”

The hazing program King was referring to began last autumn. Basically, it involves the use of explosive noisemakers and the deployment of men throughout the refuge to scare birds away.

Other options under consideration include harvesting the aquatic vegetation, either while the ponds are full of water or after they are emptied. This option could be combined with a plan to trap coots and other waterfowl so that they could be removed from the area and released in safe habitats.

The bureau could also take no action except to increase the hazing program and step up warnings to the public not to hunt at the refuge or eat waterfowl taken there. One proposal calls for the erection of a fence to keep individuals out of the area. Southeast Asian refugees are reported to forage for food at the refuge.

Another alternative involves removing the water from one of the 12 ponds and sterilizing the basin to see what effect there would be on ground water after the pond is refilled.