a. The radioactivity in sea water is not depleted by adsorp- 
tion by the bottom solids, or by the uptake of marine organisms. 
b. Natural radioactive decay has been neglected. 
c. The diffusion process is considered to be Fickian. 
d. The ocean is considered to be of uniform depth. 
The assumption of Fickian diffusion implies that the dispersion of 
a contaminant at distances from the source is much slower than is known 
to occur. The assumptions of no adsorption by bottom solids and marine 
organisms, and no radioactive decay obviously lead to an overestimate 
of the concentration of contaminant. 
Several cases are considered, corresponding to possible conditions 
of release of the contaminant to the sea. These are summarized below. 
Sustained Gross Source. This case is analogous to the continued 
release of a contaminant, at a known rate, as from the end of a pipe, or 
the diffusion of contaminant from ruptured canisters, under a steady 
state condition of supply and rupturing of canisters. 
Considering a bottom disposal area of dimension L x L, over 
which the water depth is D, with a uniform current of speed U parallel 
to the coast, and a diffusivity coefficient K, the maximum concentration 
of contaminant C, along the axis of the current at distance x from the 
source, (when x is large compared with L) for a rate of supply Q, is 
given by: 
(1) 
The maximum concentration at various distances as evaluated 
from equation (1) are listed in Table IV for the following conditions: 
Rate of supply Q= 100 curies per year (274 mc/day) 
Depth of water D = 30 meters (90 feet) 
Diffusivity coefficient K = 1 cm?/sec 
Current velocity U - 10 cm/sec (approx. 5 n.mi/day) 
20 
