tion are non-hydrocarbons, and do not elute from silica gel in either 

 hexane or benzene. These components may be largely responsible for 

 the toxicity of the test oils to marine bacteria. This observation also 

 made by the UT group for algae may have important implications for 

 our understanding of the mechanism of oil spill damage. 



It was observed that for any given oil, the toxicity to marine bac- 

 teria was dependent on the concentration of organic nutrients avail- 

 able to the bacteria. When data from all 5 oils were averaged, the 

 following numbers were calculated: 



Cone, of yeast extract % reduction in growth 



in culture medium ( % ) relative to control 



0.1 10% 



0.05 20% 



0.01 50% 



Low organic nutrients were accompanied by a greater relative toxicity 

 to marine bacteria in the presence of water soluble fractions of oil. 

 Although it is not legitimate to extrapolate the above data to the very 

 low concentration of dissolved organic matter typically found in the 

 oceans, it is clear that the concentration of water soluble fraction re- 

 quired to produce toxicity in the ocean should be much lower than 

 concentrations required in laboratory experiments. 



When bacteria which had been grown in the presence of WSF's at 

 each of the yeast extract concentrations above were re-inoculated into 

 media without WSF, their growth was equal to or often better than 

 untreated controls. 



Hydrocarbon Solubility 



Since hydrocarbons dissolved in seawater are toxic, it is important 

 to establish the solubility of several types of hydrocarbon molecules. 

 The Florida State University group has made these measurements. 



The true solubilities of several aliphatic and aromatic hydrocarbons 

 were determined in both distilled water and seawater (Table 4). In 

 most cases, the seawater solubilities represent new additions to the lit- 

 erature. It was determined that the solubility of the aromatic hydro- 

 carbons was related most closely to their molar volume and Lewis 

 basicity. These hydrocarbons are "salted out" with increasing salinity 

 and the salting coefficients were the same whether the hydrocarbons 

 existed in pure solution or in simple mixtures. 



The Florida group studied the levels of hydrocarbons in ocean 



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