1104 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1957 



Table V — Oxygen Consumption by Marine Bacteria in BOD Test 



WITH Poly(Vinyl Chloride) Plastics, Epoxide Casting Hesin 



OR Jute as Only Sources of Organic Carbon 



Test Material 



PVC — no plasticizer (rigid) 



PVC — tricresvl phosphate (TCP) 



PVC — di-2-ethvlhexvl phthalate (DOP) 



Shore A" 88 



PVC — polyester A 



Epoxide casting resin 



Jute 



Controls (inoculated sea water) 



* All free O2 in sea water consumed. 



O2 Consumption After Weeks of Incubation 



carboy containing 0.01 per cent ammonium phosphate. Nitrogen is 

 introduced into the carboy immediately. When the sea water is cool, 

 inoculum, which is prepared as described for the aerobic procedure, is 

 added and additional nitrogen pressure placed on the carboy for filling 

 the test bottles. Since anaerobic activity is usually slower than aerobic, 

 the time in test is increased. Analysis for hydrogen sulfide in the sea 

 water is carried out at 0, 4, 8, 12 and 16 weeks. Since the sulfate-reducing 

 bacteria are ubiquitous anaerobic marine species, the hydrogen sulfide 

 produced by them in the course of breaking down organic material is 

 used as an indicator of their activity. The sulfide in the sea water is de- 

 termined volumetrically according to the method described in the Oflficial 



Table VI — Oxygen Consumption by Marine Bacteria in BOD 



Test with Poly (Vinyl Chloride) Plastics 



as the Only Source of Organic Carbon 



Plasticizer 



Nitrile rubber/polyester C 



Nitrile rubber 



None' 



None' 



Tri-2-ethvlhexyl phosphate 



Di-2-ethvlhexvl phthalate (DOP) Shore A 62 



Polyester E/DOP (BTL 46-55) 



Controls (inoculated sea water) 



* All free O2 in sea water consumed. 

 ' Semi-flexible PVC copolymer. 



O2 Consumption After Weeks of Incubation 



ppm 



10.3 

 9.2 

 3.7 

 4.0 



11.7 



6.4 



* 



3.5 



ppm 



12.9 



12.3 



4.2 



5.5 



14.4 



8.4 



4.5 



ppm 



21.4 

 18.7 

 6.5 

 8.4 

 23.1 

 11.5 



7.1 



ppm 



* 

 * 



10.5 



11.0 



* 



* 

 9.7 



