330 



submarine canyons along this stretch of the continental shelf may play an im- 

 portant role in the mixing processes. Direct current measurements in the 

 canyons are needed to evaluate this hypothesis. 



While the observations necessary for an evaluation of the physical oceanog- 

 raphy are being made, water samples will also be collected for chemical analyses. 

 Various heavy metals, pesticides and their residues, petroleum products and 

 detergents analyzed in samples throughout this part of the continental shelf 

 should provide a present-day baseline for evaluation of further changes (see 

 Section c. below). 



Biological samples for both plankton and benthos would also be necessary to 

 define the present distribution of the organisms in this marine ecosystem. In 

 some cases, particularly for oil and pesticide residues which accumulate in the 

 lipid pool, an analysis of the organism may be more informative than an analysis 

 of the water. It is known that the biological characteristics of this stretch of the 

 continental shelf are quite variable and it is important to know existing condi- 

 tions so that future changes can be evaluated. The biological sampling plan of 

 operations would be to select pairs of "standard" stations at various locations 

 along the coast. One station of each pair would be selected as a potential indi- 

 cator of pollution effects, while the other station would be selected for similar 

 environmental characteristics (type of bottom, water flow, etc.) in an area 

 more remote from pollution. Periodic sampling of these pairs of stations will 

 establish the present-day baseUnes and detect biotic changes as a result of addi- 

 tional environmental modifications. 



In this field program, cooperation of other marine laboratories to evaluate 

 local conditions would be particularly valuable. Each of the major estuaries 

 discharging into this stretch of the Atlantic coastline will require intensive study 

 and evaluation. All of them are definitely polluted at present. Studies of the 

 local distribution and the seaward extension of selected pollutants will give us 

 an indication of how far the effects extend from shore and the pollutants may 

 also act as tracers and help to evaluate the rate of exchanges between the coastal 

 water and the deep sea. 



6. Domestic pollution 



There are many questions concerning the advisability of adding domestic pol- 

 lution directly into the sea, and the rate at which this can be done without 

 deleterious effects. Our ongoing program concerning the use of domestic pollu- 

 tion as a possible fertilizer for sea water has already been mentioned. This 

 program may answer some questions, such as the rate of addition of domestic 

 pollution that can be tolerated by the ocean without over fertilization and 

 eutrophication, the advantages of secondary treatment prior to discharge of the 

 domestic pollution, the potential advantages of tertiary treatment in which the 

 fertilizing elements, such as phosphorus and nitrogen, are removed from the 

 pollution, and the survival of various viruses in the sea water with the possible 

 danger of transmittal of disease by discharging sewage at sea. We have some 

 approximations to some of these questions, and it is easy to see, for example, 

 that the estuary of the Hudson River is over fertilized by the pollution discharged 

 by the Metropolitan New York area. It seems clear that secondary treatment 

 alone will not cure the problems of the pollution of the Hudson River estuary 

 but it is uncertain how much more could be achieved by more refined treatment 

 methods. 



The sewage slude resulting from secondary treatment plants presents another 

 kind of problem. For forty years, sewage sludge has been dumped at sea off New 

 York and it has had seriously damaging effects on the bottom populations in 

 the dumping area. There is evidence for the accumulation of petrochemicals and 

 of heavy metals in the sludge deposits. The presence of these toxic materials may 

 have inhibited the bacterial breakdown of the organic materials in the sludge. 

 The rate of addition of organic sludges to the coastal zone should not exceed 

 the rate at which these materials can decay so that the marine environment can 

 recover from the addition. Unfortunately, we do not know the rate of decay nor 

 whether this is inhibited by toxic components of the sludge. Precise answers are 

 not yet available as to an acceptable rate of disposal of this type of material. 



There are several proposals for the disposal of sewage in the deep water off 

 the edge of the continental shelf, either by a direct pipeline or by barging mate- 

 rial out to sea. At first glance this seems to have the advantage that the best 

 fishing areas can be avoided. The deep sea, however, is a very constant environ- 



