3. Sorption onto selected clay minerals has been studied and is 
recommended as a means of solution decontamination, under certain 
conditions. 
4. The differences in composition between marine sediments and 
the solids carried to sea by rivers is attributed to exchange and sorp- 
tion reactions between the solids and dissolved substances during sedi- 
mentation. 
5. The sediments in the area around the end of the discharge line 
from the British Atomic Energy Authority processing plant at Windscale 
on the shore of the Irish Sea, show a relatively large accumulation of 
radioactive substances. 
Although some of this information is quantitative it cannot be ap- 
plied directly to the dispersal problem we are considering. Neverthe- 
less, since radioactive waste components and naturally occurring sus- 
pended and deposited solids generally exhibit exchange and sorption 
reactions; and since the disposal canisters will be partially or perhaps 
completely buried in bottom deposits during the time the waste com- 
ponents are escaping from them, it seems inevitable that these reac- 
tions will have a major influence in controlling the rate of dispersal 
and ultimate distribution of the wastes. 
These sorption and exchange reactions appear to us to be a safety 
factor (an exception is noted below) in disposal problems. So far as 
uptake by permanent bottom deposits are concerned the effect is that of 
achieving additional containment time, thus providing for greater radio- 
active decay than would be achieved by containment only in the canister. 
There is at least one situation in which sorption onto bottom de- 
posits may represent the development of a possibly hazardous situation. 
This is the situation in which bottom areas adjacent to a disposal site 
are the source of marine food products such as oysters, clams, mus- 
sels, etc. In this case accumulation of wastes on the bottom would pro- 
vide for a greater level of contamination of the food product than would 
occur in the absence of sorption and exchange with the bottom. Our 
recommendation of a complete survey of a proposed inshore disposal 
area prior to the start of disposal operation will help preclude the de- 
velopment of such a hazard. 
Because we are unable to make a quantitative estimate of the 
magnitude of uptake on suspended and deposited solids, we have neg- 
lected this factor in our evaluation of the quantities of wastes likely to 
be found in the water and in marine food products for various rates of 
disposal of radioactive wastes. We believe that by neglecting this 
factor our recommendations concerning disposal rates include a safety 
factor of at least 10, and possibly more. 
Z5 
