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There are, of course, many substances which are harmless, or 
relatively harmless, to the marine environment. Most construction 
materials such as bricks, rock fragments, cement, and wood are in this 
category and the main caution is that they not be dumped in areas 
heavily populated with bottom dwelling (benthic) organisms. Dredged 
materials are generally harmless although, there is some danger when 
dredging is done in highly polluted sediments. Transport of polluted 
material to a clean area may simply result in spreading the pollu- 
tion. For example, it was reported earlier this year in the harbor 
at Cleveland, Ohio, some 17,600 tons of oil and grease were found 
in 660,000 tons of solids removed during 1966-67 dredging opera- 
tions (5). ; 
In summarizing my comments on the nature of the material dumped 
I repeat that any material will cause some change in the environ- 
ment. This change can vary widely from a trivial effect to a very 
serious effect. We need immediate action to prevent dumping of the 
most hazardous chemicals but it would be possible to postpone action 
on the less harmful substances until studies have been completed 
for suitable standards and localities for dumping. 
In picking disposal sites I would like to emphasize that it is just 
as important to understand the bottom currents as the surface cur- 
rents since the former control the movement of soluble and neutrally 
bouyant materials leaking from the dump. The item I am holding 1s 
called a seabed drifter. It enables us to determine the residual drift 
along the sea bottom in much the same manner as drift bottles are 
employed at the surface of the sea. 
The way this works is that you take a series of these, and you clamp 
them together with a salt spool and drop them from either an airplane 
or a boat. The salt spool carries the whole group to the bottom. The 
salt dissolves and each one of these separates. The residual current on 
the bottom will then carry this thing along the sea bottom very much 
like this. There is a small weight on here that gives it neutral bouyancy. 
In figure 1, which I have at the end of my statement, the same one 
that showed the mercury, you will see a whole series of arrows. These 
arrows show the general direction of residual drift on the sea floor 
bottom in the area from Delaware Bay to Nantucket. You will note 
that most of the arrows on the north side of the dashed line show 
movement back toward the land. This means that many of the soluble 
or suspendable items that are dumped west of this line will eventually 
find their way to the nearshore area which has the greatest concentra- 
tion of marine life and recreational facilities. On the next page is a 
figure called percent of SBD. That means seabed drifter, these little 
gadgets, launched and recovered on coasts or estuaries. The colors 
don’t show too well on this copy, but you will notice the darkest areas 
in toward shore are the areas where the largest percent of samples 
dropped found their way back to shore. The New Jersey-New York 
area has one of the highest recoveries of drifters dropped at sea, and 
therefore represents one of the worst areas along the coast for 
dumping. boo 
Beyond the 100 fathom line which is out at the edge of that colored 
area, almost none of the drifters were recovered so this area is rela- 
tively safe from the standpoint of having dumped materials coming 
back to shore. These deeper areas, however, do contain bottom dwelling 
