likely, that an addition 10 curies of 729+2*°py (associated with soil)
could be brought to Runit Island for disposal.

If this contaminated

soil were spread on the northern end of Runit Island, plutonium would be
expected to leach from the soil to the groundwater and subsequently
reach the lagoon.

The rate of remobilization would be similar to the

rates presently assessed from available island data.

Our best estimate,

based on average groundwater residence times on Runit, present plutonium

concentration in soil and groundwater, is that it will require more than
10° years to remobilize the present plutonium inventory from the island
soil to the groundwater by natural processes.

It is estimated that

presently 0.23 mCi of 239*24°py annually migrates to the lagoon via groundwater at Runit.

0.23 mCi represents less than 0.01% of the current plutonium

inventory in the water in the entire lagoon.¢

Therefore if the Runit

terrestrial plutonium inventory were doubled (i.e., an additional 10 Ci),
the groundwater concentration would eventually double and then contribute
an estimated 0.02% to the lagoon inventory as measured in 1972.

We have

found that the concentrations of plutonium in the lagoon water has been
essentially

non-varient over the last 10 to 15 years since testing stopped.

However, we are not in a position to predict what the lagoon inventory

will be in hundreds and thousands of years from now.

The concentration

of plutonium in fish is related to the concentration of plutonium in water.
Therefore an increase in water concentration of 0.01% will increase present
fish concentrations by 0.01% and subsequent dose to man through consumption
of marine products by 0.01%.

Select target paragraph3