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Title: Application of biological barriers in maintaining the integrity of radioactivity in shallow burial grounds

Conference ·
OSTI ID:5562157

Stabilization of a shallow burial site requires some means of keeping buried radioactive wastes in place and preventing the movement of radioactive elements into the biosphere by various vectors present in the soil covering the burial site. By placing a barrier between the surface of the soil and the buried wastes, it would be possible to isolate the wastes from the biosphere and eliminate the movement of radioactive elements into the environment. An effective biobarrier would make it possible to grow plants over the buried wastes regardless of rooting habits; the plants would stabilize the surface soil, prevent wind erosion, and transpire soil water back into the air, thus preventing it from percolating downward through the buried wastes. This report summarizes the finding of a study undertaken to determine the effectiveness of natural cobblestones as a long-term biobarrier. In the initial field study, we investigated whether a thick layer of cobblestones would prevent plant roots and burrowing animals from reaching contaminated materials and transferring radionuclides to the soil surface. In a subsequent greenhouse study, three modifications of the cobblestone barrier were tested, including the addition of another layer of stones, one of asphalt, and one of a root toxin. These data show that cobblestone can be effective as a barrier to burrowing animals and insects, but not totally effective as a barrier to plant roots. Because of variable weather patterns at Hanford, five to six year studies are recommended for further studies on the effectiveness of different materials as biobarriers to radioactive substances. Stone size appeared to affect the plants' rate of root growth since root growth slowed in the air spaces between stones. Root toxin was 100% effective as a means of keeping roots out of the buried waste; this method could be used as a barrier modification where no plant cover is needed.

Research Organization:
Pacific Northwest Lab., Richland, WA (USA)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
5562157
Report Number(s):
PNL-SA-7142; CONF-790728-8; ON: DE82007090; TRN: 82-007831
Resource Relation:
Conference: 24. annual meeting of the Health Physics Society, Philadelphia, PA, USA, 7 Jul 1979
Country of Publication:
United States
Language:
English