Approximately 2,000 acres of land in the center of the Hanford Reservation is contaminated with an estimated 14 Ci of /sup 137/Cs and 81 Ci of /sup 90/Sr associated with animal wastes. Approximately half of this activity is located on (or within) 2.5 centimeters of the ground surface. The source of the contamination was the B-C Cribs and trenches which were used as liquid radioactive waste disposal sites during the 1950's. The mechanism for movement of radionuclides from the disposal site to the ground surface is believed to have been burrowing by an animal (probably a badger) followed by use of the exposed material as a salt lick by rabbits and other animals. When the radioactivity was discovered, the burrow was sealed, the contaminated site was classed as a radiation zone, and surveillance initiated. The contamination site has not been a significant hazard to employees at the plant or to the public. The Atlantic Richfield Hanford Company maintained control over the surface contamination by isolation, zoning, and by continued surveillance. Methods of handling the contaminated area have been considered. Discussions of these alternatives and applicable safety analysis information are included in this document.

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