Extent of Contamination Unclear at Sea Floor Site

One thing is certain about the radioactive waste at the Gulf of the Farallones National Marine Sanctuary--no one knows much about it.

Government tests have shown low levels of radiation leaking from the corroding drums that were dumped between 1946 and 1970 at what was then the Farallon Islands Nuclear Waste Site. The U.S. Geological Survey has studied only 15%of the almost 48,000 55-gallon drums.

How that waste has moved through ocean currents and affected marine life is even less documented.

In 1996, ecologist Thomas Suchanek studied deep-sea bottom-feeding fish harvested for food--Dover sole, sablefish and two different species of thornyheads--from the waste site and from Point Arena, about 62 miles north.

Suchanek tagged and tracked the fish, which can go as deep as 1,200 feet, and tested them for cesium 137, plutonium 238, 239 and 240 and americium 241. For cesium and plutonium, levels were near background, but for the americium, an artificially produced element, levels were elevated.

Americium is used in industrial measuring devices, such as gauging thickness in the glass industry, in radiology and in household smoke detectors. Some is also produced from plutonium in nuclear reactors.

Because the fish studied move around so much--some went as far away as Japan--it’s unclear if they were contaminated at the Farallones or at another site contaminated by humans somewhere in the ocean.

“It’s possible that the nuclear waste might be transported from the Farallones up north; it’s possible that all these areas are contaminated,” Suchanek said. “It’s unclear how long any individual fish would spend feeding along the dump site.”

Suchanek, now a deputy director of environmental contaminants with the U.S. Fish and Wildlife Service, recommended then and still advocates examining organisms that live their entire lives near the nuclear waste, such as worms and crustaceans that live in sediment.