1108 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1957 



ceptible plasticizer into the sea water medium might greatly accelerate 

 utiHzation of that material and be reflected in rapid oxygen consumption. 



Five different elastomers have been evaluated by the BOD test to 

 date. The results with aerobic bacteria are presented in Table VIII. 

 First, it is apparent that all of the elastomers tested can serve as a source 

 of carbon for the bacteria. As may be noted in the table, GR-S jacket 

 (54-14), butyl jacket (54-19) and natural rubber (54-23) are oxidized 

 at about the same rate — all oxygen being consumed from the test me- 

 dium between the third and seventh day analyses. GR-A (54-18) and 

 neoprene jacket (53-164) are more resistant than the other three elas- 

 tomers in the test. During the fourteen-day test period, approximately 

 twice as much oxygen was consumed in the case of the GR-A as with 

 the neoprene. 



The results of anaerobic bacterial activity, as reflected by analyses 

 for hydrogen sulfide in the sea water medium, are contained in Tables 

 IX to XII, inclusive. As with the results of the aerobic test, materials 

 in a given test run are included in the same table. No polyethylene is 

 utilized as a source of carbon by the sulfate-reducing bacteria. In no 

 case is the production of hydrogen sulfide, with different polyethylenes 



Table X — Hydrogen Sulfide Production By Marine Bacteria 



IN Anaerobic Sea Water Test with Poly (Vinyl Chloride) 



Plastics, Epoxide Casting Resin, or Jute 



as Only Sources of Organic Carbon 



Test Material 



Poly (Vinyl Chloride) Plastics 



No plasticizer (rigid) 



Tricresyl phosphate (TCP) 



Di-2-ethylhexvl phthalate (DOP) Shore 

 A 88 ^ 



Polyester A 



Nitrile rubber/polyester C 



Nitrile rubber 



No plasticizer^ 



No plasticizer' 



Tri-2-ethvlhex3d phosphate 



Di-2-ethylhexyl phthalate (DOP) Shore 

 A 62 



Polyester E/DOP (BTL 46-55) 



Epoxide casting resin 



Jute 



Controls (inoculated sea water) 



1 Semi -flexible PVC copolymer 



H2S Production After Weeks of Incubation 



ppm 



1.90 

 0.22 



0.26 

 2.60 

 1.50 

 4.10 

 0.22 

 0.32 

 0.26 



0.22 

 12.20 

 0.16 

 1.90 

 0.10 



ppm 



3.50 

 0.22 



0.26 

 38.40 

 7.00 

 9.60 

 0.22 

 0.64 

 0.96 



0.22 

 61.40 



0.64 

 13.40 



0.64 



12 



ppm 



4.20 

 0.64 



0.26 



38.40 



19.98 



12.40 



0.90 



1.89 



1.86 



1.09 

 94.10 



0.86 

 38.60 



0.70 



16 



ppm 



5.60 

 0.38 



0.61 



47.70 



18.60 



11.50 



0.51 



1.02 



0.99 



0.58 

 82.90 



0.48 

 52.20 



0.58 



