In contrast to the low levels of hydrocarbons being discharged in 

 produced water, some 207 kg of sulfur were estimated to have been 

 discharged daily from BGOF production platforms. As sulfur has a 

 specific gravity of about two and is insoluble in water, it may serve as 

 the major transporter for oil through the water column and into 

 sediments, if hydrocarbons can be adsorbed on sulfur particles. The 

 acrolein biocide used to control microbial aggravated corrosion of pipes 

 and vessels was not detected in produced water discharge samples „ This 

 biocide, while highly toxic, is quite labile. 



As mentioned above, particulate sulfur was a major component in the 

 produced water and, along with metal flakes from the platform, may have 

 served as a transporter of hydrocarbons to the bottom. Hydrocarbon 

 levels in sediments beneath the production platforms, although highly 

 variable, were typically higher than levels in sediments in control 

 areas. Another possible transporter of hydrocarbons to the bottom was 

 oily sand which was sometimes present in the skim tank and discharged 

 overboard. 



With the exception of the large pieces of metal and barnacle 

 shells, the residence time of particulates beneath the platform was 

 presumably very short due to resuspension (waves) and transport out of 

 the area (currents). The direction of sediment transport appeared 

 controlled by seasonal current patterns. Dilution and/or biodegradation 

 appears to reduce levels of contaminants to that of background 

 conditions within short distances (<50 m) from the platforms. 



The bacterial data provided evidence that the degree of hydrocarbon 

 contamination emanating from the Galveston field was, indeed, minimal. 

 Bacterial diversity and density levels in the BGOF were markedly similar 

 to those in control areas. Although numerical densities and taxa 

 represented in collections from the two areas were the same, the 

 relative abundance of taxa was different between the BGOF and control 

 areas. BGOF samples contained relatively more oil-degrading, 

 sulfur- oxidizing, and sul fate-reducing bacteria than did samples from 

 control areas outside the field. These data indicated chronic, 

 low-level pollution was occurring, but not to the extent that population 

 levels were significantly increased. 



Produced water inhibited or retarded the growth of laboratory 

 cultures of bacteria, but appeared to have either no effect, or a 

 stimulatory effect, on isolates obtained from the BGOF. Both pure and 

 mixed cultures of bacteria from the BGOF exhibited the ability to 

 degrade significant portions of the n-alkanes in BGOF crude oil . 



Tillery (1980) found that produced waters were enriched in barium 

 and strontium, but characterized the levels of other trace metals in the 

 discharge as being extremely low. These findings confirmed the previous 

 work of Anderson and Schwarzer (1979), also performed in the BGOF. 



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