rubber cement. The specimens were positioned so that one set of ropes and electrical 

 cables would be buried in the sediment (in which bacteria are ordinarily most active) 

 and an identical set would be exposed about 3 feet above the sediment. 



Table 8. Materials Used in the Formulation of Insulating Materials Tested 



Test Specimen 



Plasticizer 



Filler 



Antioxidant 



Polyethylene (standard 

 polyethylene insulation) 





- 







Polyvinyl chloride 



- 



- 



- 



Government rubber 

 styrene (styrene 

 butadiene rubber) 



Cumarone-indene 

 resin and micro- 

 crystalline wax 



Hard clay and 



water-ground 



whiting 



Polymerized 



trimethyl 



dihydroquinoline 



Silicone rubber 



- 



- 



- 



Neoprene (Type W) 



Light process oil 

 and petroleum 



Hard clay 



4, 4 thiobis (6- 

 tert-butyl m- 

 creosol) 



Metal test specimens were also placed on the STU, but materials containing 

 antifouling paints or other toxic substances were excluded from exposure aboard the 

 STU. The current velocity at a depth of 2,340 feet (about 0.3 knot) was not great 

 enough to carry away any water-soluble toxic substance which might alter the 

 natural biological fauna found in the immediate vicinity of the STU. 



RESULTS 



Recovery of Test Materials 



As soon as the recovered STU was placed on the deck of the ship, the test 

 panels were examined and any attached organisms were photographed. The animals 

 were then carefully lifted from the test specimens and preserved in a 5% glycerol - 

 alcohol solution for further examination and analysis in the laboratory. 



As soon as the STU was secured to the deck, the bio-racks attached to the 

 side of the STU (Figure 7) were disassembled. The individual test specimens were 

 placed in plastic bags for later examinations, tests, and evaluation in the laboratory. 



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