After release to the sea, following intentional introduction of 
liquid wastes or after rupture of a canister, the concentration of the 
waste will be continually diminished by dilution brought about by the 
natural turbulent mixing processes that occur in the sea, and the mix- 
ture of waste and sea water will be moved from the disposal site by 
ocean currents. An evaluation of the extent of dilution together with 
processes that might combine to return the wastes to man are discussed 
below. 
TRANSPORT AND DISPERSION 
The movement of a contaminant from the disposal area and its 
dilution with sea water will be controlled by circulation in and adjacent 
to the disposal site and the natural turbulent mixing processes in the 
sea. Obviously, the bottom water circulation in the immediate area of 
the disposal site will control the initial movements of the soluble and 
finely divided waste as it diffuses from the ruptured canister. 
Movement of Bottom Sediment 
The mechanisms and patterns of bottom sediment transportation 
on continental shelves are poorly understood. The general circulation 
of the near-bottom water does not wholly control the movements of 
bottom sediments since tides, waves, storm surges and tsunami impose 
controls which may in fact outweigh in importance the average circu- 
lation of near-bottom water. Important in such considerations is the 
recent conclusion independently proposed by several groups studying 
the sediment budget of North Sea beaches that up to half the sediments 
contributed to certain advancing beaches has been derived off shore 
from the floor of the North Sea. The possibility thus exists that detri- 
tal waste may reach adjacent beaches in undesirable quantities. 
The base of effective wave action has been variously estimated at 
30 feet to 900 feet. The discovery of strong scour on seamounts and on 
the Mid-Atlantic Ridge to depths of 2000 fathoms has been interpreted 
as evidence that there is no effective wave base. On the other hand, 
most geologists believe that really intense wave action is limited to the 
upper 30 to 100 feet of the ocean. Because movement of bottom mate- 
rials can be quite independent of the average water circulation since it 
partly depends on wave action and not wholly on water transport, it 
must be considered separately. Before extensive inshore dumping is 
commenced, it would seem desirable to dump harmless trace material 
and observe from what distances appreciable material reaches the ad- 
jacent beaches. 
Near-bottom Water Circulation 
Sub-surface circulation has not been studied with sufficient detail 
to provide a basis for reliable prediction of the direction and speed of 
transport at all seasons of the year in any location that might be chosen 
for a disposal area. Evaluation of bottom circulation must be inferred 
from observations of salinity and temperature distributions, and 
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