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Soil Cleanup to Begin Next Week

(Photo - shield wall parts in the 'bone yard')
Shielding pieces in the "Bone Yard" near the SLAC linac. (Photo by Nicholas Bock.)

Starting next week, expect to see a little more traffic and a little less dirt around the SLAC campus. The Department of Energy Environmental Management Office is beginning soil cleanup work at seven sites, including the artificial ridge and the lower salvage yard on the south side of the Klystron Gallery, and what's known as the "Bone Yard," a site on the north side of the Klystron Gallery where old shielding blocks rest. To lead the soil removal, the Department of Energy has contracted CPE, a company run by three small business organizations: Cape Environmental Services, Terranear PMC and ECOR Environmental Services. The DOE Environmental Management Office's Federal Project Director Kevin Bazzell will manage the performance of CPE. The removal will continue through August and into the fall until rainy weather forces a stop. Remaining work will resume in the spring.

"People can expect to see earth-moving equipment in areas like the artificial ridge and the Bone Yard," said CPE Environment, Safety and Health Manager Tim Campell, who has been working on the project with SLAC personnel for the past year. "We're working very closely with Janice Dabney, Javier Sevilla, Simon Ovrahim and SLAC security, and SLAC ES&H groups to coordinate movement. We're also working with building and area managers so they are well aware of our plans. We'll try to limit as best we can any impact to the site employees." CPE is also working with SLAC's own Environmental Restoration Group to take on the project. "Everyone at SLAC has been great to work with," Campbell added, "and we greatly appreciate their efforts."

The decision to clean up the sites came after a multi-year DOE soil sampling campaign that was so extensive it even took dirt from SLAC flowerbeds. The survey found some non-hazardous contaminants such as motor oil in certain sites, to be removed from the dirt. There are also some heavy metals to remove, notably lead that has flaked from the old shielding blocks. The DOE Environmental Management Office Facility Representative Jeffry Parkin emphasizes that none of the contaminants are radioactive, and they do not pose a risk to anyone near these areas, either through the air or water. In fact, he said, workers clearing the soil away are not required to wear chemical personal protection equipment while they work on the sites.

"'Cleanup should give the impression of good," said Parkin. "We're taking bad things away." Keeping the campus soil clean is part of the DOE's responsibility in the land lease with Stanford University.

"We'll take more samples and as we find contaminants we'll start to scrape soil off," said Parkin. "If we haven't got it all yet, we go down another few inches. Our samples verify our goals." Parkin expects that the project will remove 25,000 to 35,000 cubic yards of dirt total. In most areas he expects they will remove eight to twelve inches of soil off the surface, but on the artificial ridge they'll remove about eight feet of depth off the eastern end. It will remain up to Stanford University to rebuild the ridge or not. Nearly all of the removed soil will be "type 2" soil and will go to the Altamonte Landfill.

—Calla Cofield
SLAC Today, August 6, 2009