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It should be pointed out that submarine canyons of one type or another cccur 
throughout much of the world ocean.. Some of these may not be appropriate 
for disposal because of the fact that they are migration routes for finfish 
or shellfish. 
CREATION OF OFFSHORE ISLANDS TO SEQUESTER VERY CONTAMINATED MATERIAL 
It- is envisaged that in appropriate places and with careful planning 
artificial islands can be created in offshore waters that will sequester 
dangerous pollutants away from the marine ecosystem and important 
groundwater supplies. This would be done by creating an island shell with 
central pits into which the pollutants could be pumped and the partially 
filled pit capped with clean material. Later the pit cover could be left 
barren or planted to appropriate vegetation to encourage development of 
habitat for sea birds. 
DISPOSAL BELOW THE ZONE OF MAXIMUM PLANKTON PRODUCTIVITY 
In areas- where disposal of dredged material must be carried out during 
periods of maximum phytop‘ankton production, it should be possible to 
ameliorate impacts by shunting dredged material below the zone of maximum 
production. As noted earlier, the lower part of this zone in temperate 
regions is no deeper than 15 or so meters. It may be feasible to pipe 
material for that depth from a sea-going barge. 
SPECIAL CARE DREDGING MEASURES 
PUMPING FROM HOPPER DREDGES TO SEA-GOING BARGE 
When hopper dredges are used more environmental concern is expressed over 
the dredging than the disposal process. This is due to the great amount of 
fine material released as the hoppers are overfilled in order to obtain as 
much sediment per shipload as possible. The turbid slurry that overruns the 
weirs often creates a massive turbid plume. Moreover, it is this fine 
material to which many pollutants are attached. And in some instances the 
