RESISTANCE OF MATERIALS TO MARINE BIOLOGICAL ATTACK 1105 



Table VII — Oxygen Consumption by Marine Bacteria in BOD 



Test with Polyethylene, Polyester Casting Resin or Poly- 



(ViNYL Chloride) Resin as Only Source of Organic Carbon 



Test Material 



Polyethylene 0.7 melt index (High Dens.) 

 Nat. + antio.xidant 



Polyethylene 0.7 melt index (High Dens.) 

 Blk 



Styrene polyester, silica-filled 



Poly(Vinjd Chloride) resin 



Controls (inoculated sea water) 



Oz Consumption After Weeks of Incubation 



ppm 



3.1 



2.9 

 5.5 

 4.2 

 2.5 



ppm 



3.3 



4.1 

 7.0 

 4.1 



3.8 



ppm 



6.1 



7.1 

 9.3 

 7.3 

 6.7 



ppm 



6.5 



7, 



12 



7 



6 



and Tentative Methods of Analysis of the Association of Agricultural 

 Chemists. 



The results of the aerobic test procedure are presented in Tables IV 

 to VIII inclusive. In these tables the oxygen consumption values ob- 

 tained with materials which went through the same test run are included 

 in the same table. The materials included in Tables IV and V, with the 

 exception of jute, were exposed in finely ground or shaved form. Since it 

 was not possible to obtain reliable estimates of the surface areas exposed 

 to attack in this case, the oxygen consumption ^'alues in these tables are 

 not directly comparable with respect to rate. The data serve the im- 

 portant basic purpose of indicating whether these materials can serve 

 as a source of energy for the bacteria. However, data in Tables VI to 

 VIII inclusive are based on the use of equally thin sheets of material 

 with about 12.9 sq cm of surface area exposed to attack. Two exceptions 



Table VIII — Oxygen Consumption by Marine Bacteria in BOD 



Test with Elastomers as the Only Source 



OF Organic Carbon 



Elastomer 



GR-S jacket (54-14) 



GR-A jacket (54-18) 



Butvl jacket (54-19) 



Natural rubber jacket (54-23) 



Neoprene jacket (54-164) 



Controls (inoculated sea water) 



* All free O2 in sea water consumed 



0-2 Consumption After Days of Incubation 



