from food crops with a concentration of three times the mean value is very
small.

Soil concentration data are also lognormally distributed with

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Similar percentages accounted for by x, 2 x, and 3 x and re-enforce those
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data observed 1n coconut meat and milk; concentrations in plants should,
overall, reflect the concentration in soil.
The observed lognormal distribution of radionuclide concentrations in
soils and plants at the atolls 1S consistent with most elemental

distributions in nature.” Also the observation that 3 times the mean value
includes more than 95% of the population distribution is consistent with
other observations several of which have recently been summarized by Cuddihy

‘ét al (43).
Strontium-90 concentration distributions in bone have been specificelly
addressed by Kulp and Schulert

(44).

They found that 20s; from fallout

was distributed lognormalliy and that the 9&th percentile value was 2.3 times
the mean value.

Maximum values observed for ?%sr in bone by Bennett were

3 times the mean; most of the data fell below 3 times the mean (18,19).
These data also reflect the combined variability of the 90s, concentration

in food products and the variability in dietary intake.
The range of values observed for the retention of 13?og in humans hes
been summarized in ICRP 10 and 10A (24,25) and NCRD 52 (26).

For exanple,

the range of observed valves for the retention time for the shart term

compartment is 0.5 to 2.1] day with a mean of 1.0 day; the upper limit thet
has been observed 18 only a factor of 2,

greater than the mean value.

For

the long term compartment the data range from 60 to 165 with a mean value of
115 days;

the maximum value in this case is less than twice the mean value.

The fraction of the intake which has been observed to go to the short term

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