Solution for contaminated soil. Bulldozers may halt a job fungus farming could do naturally

IT was basic research, on the surface the sort of dust-dry topic that wouldn't raise an eyebrow outside of the laboratory: to find out what caused the element selenium to con-vert to gas and escape from the soil. But what University of California professors William T. Frankenberger and Ulrich Karlson soon uncovered promised nothing less than a practical, inexpensive solution to a problem of catastrophic proportions for wildlife - and agriculture as well: selenium contamination, associated with heavy irrigation in desert-type climates.

That problem gained nationwide attention a few years ago when it was found that chicks born at the Kesterson National Wildlife Refuge in central California were grossly deformed. The cause: selenium in the diet of the adult birds.

This natural soil element had been unnaturally concentrated at Kesterson by drainage water from surrounding farmlands. Funding for the canal destined to discharge the drainage water in the San Francisco Bay area ran out, and the canal stopped short at Kesterson, in effect, turning it into a chemical dump, a toxic disaster covering 1,200 acres. The discharge from the canal has since been stopped but the damage had been done.

On the surface everything is serene. Birds still abound, but after eating the seeds of the contaminated vegetation they are unable to reproduce viable offspring. And, just as a wayward lobster trap, broken from its mooring, continues to trap lobsters year after year, the poisoned Kesterson waters continue to attract birds into a futile nesting ritual.

To solve the problem, the State of California is about to resort to the bulldozer. At a cost of some $50 million, it plans to remove all the vegetation and the top six inches of soil and mud and dump it into a landfill with a liner that cannot be guaranteed for more than two years. In effect, a toxic dump will be created to house what under normal circumstances is some of the most fertile soil anywhere.

Meanwhile the University of California scientists are calling for a little time to prove in the field what their exciting findings in the laboratory show is possible. Fungus farming, they say, could be the natural and inexpensive answer; the bulldozer might never need to move in at all.

Following the original directive, professors Frankenberger and Karlson discovered that the organisms at work converting the selenium to a harmless gas were a family of related fungi.

Identifying these agents was no more than expected; the surprise came when the scientists discovered how readily the fungi could be stimulated to work at rates thousands of times faster than normally occurs in nature.

This was accomplished when ``certain management techniques'' basic to good farming practices were carried out. With the addition of carbon, in the form of straw, pectin in orange peels, and certain trace elements, to the soil, the fungi would take off. ``In the lab we had miracle results,'' says Frankenberger. ``We'd often get 40 to 50 percent of the selenium removed from a soil sample in one month.''

Apparently the fungi thrive on the organic matter and other nutrients, including micro quantities of selenium. But, in a defensive measure against a toxic buildup of selenium in their tissue, they get rid of the excess by converting it to a gas that passes harmlessly out of the soil.

Following the laboratory results, in late August last year Frankenberger and Karlson were given test plots to monitor the process at Kesterson. Unfortunately the plots are about to be bulldozed away by the proposed cleanup, ``well before we have had a chance to properly monitor the results,'' says Frankenberger. In effect the field testing began just at the onset of cooler weather when all biological activity begins to slow down. ``We need to continue the tests through the summer,'' he says.

The importance of this work extends beyond Kesterson. More recent discoveries show selenium contamination cropping up elsewhere in the US.

The Stillwater Wildlife Management Area, some 60 miles east of Reno, Nev., has been added to the list of contaminated areas, and last year California authorities had to warn people not to eat coots taken from the Tulare Lake Basin north of Bakersfield because excess concentrations of the element had been found in the flesh of birds taken from there.

Increasing numbers of birth defects in birds have been noted at Ouray National Wildlife in Utah, Benton Lake in Montana, and the Kendrick irrigation project in Wyoming. They can't all be bulldozed into oblivion, Frankenberger contends. ``Presumably it [selenium contamination] exists in other parts of the world, too,'' he says.

Frankenberger concedes it is too late to save Kesterson from the bulldozer, but he is asking that the less than 2 acres covered by the test plots be left untouched. He is less than optimistic, however. Some interests, it seems, would prefer to see the natural system fail.

``When you're talking $50 million in contracts, you're talking a lot of politics,'' Frankenberger says. But, as he points out, it's not just wildlife that will benefit. Unless a natural, inexpensive solution is found, irrigation farming in these areas is doomed as well.

You've read  of  free articles. Subscribe to continue.
QR Code to Solution for contaminated soil. Bulldozers may halt a job fungus farming could do naturally
Read this article in
QR Code to Subscription page
Start your subscription today