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SPECIAL CARE DISPOSAL AREAS AND SITES 
RATIONALE FOR DEEP OCEAN DISPOSAL 
Special consideration is given to deep ocean disposal as a “special care“ 
measure. The arguments in favor of this proposal are numerous but some of 
the more cogent are that (1) there will be an amelioration of effects during 
d long transit in the water column, there being large areas and immense 
volumes of water to dilute materials, (2) there is a marked reduction of 
animal biomass in offshelf waters as compared with onshelf waters, (3) there 
are no commercial fisheries below depths of 800-1000m (and probably never 
will be), and (4) the deep ocean basins, of all places, have been receiving 
large amounts of sediment since their creation. 
HYPERSALINE BASINS 
Anoxic hypersaline basins exist on the outer continental shelf and upper 
continental slope of the northern Gulf of Mexico and elsewhere. The largest 
basin so far studied is about one-third full of brine that is 8.6 times as 
salty as the normal seawater overlying the basin. It is thought that suf- 
ficient seawater dissolution of the associated salt dome to completely fill 
the basin with brine will take at least 30,000 years. 
The basins are devoid of life except for simple bacteria whose utilization 
of organic matter produces methane, ammonia, and hydrogen and keeps the dis- 
solved oxygen content of the brine at zero. 
SUBMARINE CANYONS 
Submarine canyons are sea-floor valleys that generally begin as notches in 
the continental shelf from which they cut as troughs into the continental 
slope and terminate in fans of sediment. They are viewed by some marine 
scientists as being ideal locations for disposal of polluted dredged materi- 
al, primarily because the floors of active canyons support very little 
life. 
