The original program design for analyses recommended a 15% replication of

samples.
Historically, due to economic considerations, the replication has
been about 9% for the total number of samples from Areas 13, 5-GMX, and Double
Tracks.
Experience has shown that the quality assurance program recommended
in the original program design was unrealistic for the safety shot site studies

due to the "hot particle problem." The particle problem was recognized early
in the safety shot site studies, and much of the data has confirmed the importance of the particle problem. Gilbert reviewed the data on replicate samples
provided by the LASL Soils Element Referee and concluded that the number of
replications necessary to detect a significant difference among laboratories
is prohibitive.
Thus, quality assurance cannot be based on real life samples
from the safety shot sites for economic reasons.
For the safety shot site

studies, this type of quality control should be discontinued or adjusted.

One

adjustment might be to follow a recommendation of the Soil Sampling and Analyses
Committee made in September, 1971, that each batch of samples could contain a

known or "standard" (prepared) sample with results of analyses to be reviewed
by the Referee.

One such sample was provided by the EPA early in 1972.

The quality assurance program will be expanded to include other radioisotopes

of interest as they are defined and in matrices encountered on NTS of interest
to the NAEG program.
Soils Element Data
The Soils Element provides a basic source term necessary to all other Elements.

NAEG vegetation studies personnel and the NAEG statistician indicated the need

for better NAEG 24am data, specifically more precise analyses (or more numerous
samples) at low levels of 24lam and determination of 2414m on the same aliquot
as used for 239°240py,
There are indications of disparity in the plutoniumamericium ratios among study sites.

It

is not known whether this is real, but

it is suspected that it ic due in part to difficulty in americium determinations.
The NAEG vegetation study personnel are also interested in concentrations of
radionuclides in the rhizosphere, since that concentration is important to

plant uptake.

A more detailed study of mounds is indicated which is designed

to determine the location, amount, and form of the plutonium and 24lam with
respect to the rhizosphere.

The importance of some profile sampling to greater depths than the originally

recommended 25 cm has been indicated.
The referenced reduction of such profile
data as were available shows anomalous distribution of Pu and Am which should

be studied further to provide data for the prediction of future distribution.
Anomalies at greater depths may exist but information is not available at this
time.
Although some safety shot site profiles have been resampled to greater
depths, the samples have not yet been analyzed.
It is strongly recommended
that future soil sampling efforts include a sufficient number of deep profile
samples to determine the maximum depth of penetration of the radionuclides of
interest and possible presence of anomalies.
The mechanisms of transport of radionuclides through the soil profile are

almost completely unknown.

Plutonium and 24am may be transported as particles,

ions, complex ions, colloids, or combinations of those states to loci of
concentration.
There is a large gap in our knowledge at this point; the
mechanisms should be investigated.
The presence of inorganic and organic

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