Soil, environmental impacts biological activity

From new data and from evaluation of published information, it appears that the magnitudes of uptake of actinide elements by plants from contaminated soil generally are less than the value used in the assessment of radiological impact for the LMFBR environmental assessment. The CR value of approximately 10-1 used in the impact assessment exceeds most observed values for Pu (Fig. 3), and appears conservative for incorporation into foods by the root pathway. Even after 30 years of residence time in the biologically active environment of the Oak Ridge floodplain, greater than 99% of the Pu in this ecosystem remains associated with the soil. The observed CR value is 10-3. For this time frame, there is no evidence that ecological or soil processes will cause the soil-to-plant transfer of Pu to approach the 10-1 value used in the LMFBR... 

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