J 



vj 



\M U 



v. 



-GASOLINE RANGE 



HMW RANGE 



Figure 2-10. — A sample spiked with Ocean 2S0 gasoline to illustrate two ranges of interest on the traces, thai for gasoline and thai for higher molecular weight (HMW) 

 petroleum and biogenic hydrocarbons. This can be compared lo the lower gas chromatographic trace in which is illustrated a small amount of gasoline components and a larger 

 amount of HMW biogenic compounds found in yellow-tail flounder collected at Station 112 in the area of the Ocean 250 spill. 



trol sample is of crucial importance in evaluating the analytical 

 results of the other samples. As Figure 2-10 illustrates, there are 

 several components in the gasoline boiling range (probably alkyl 

 benzenes) present in the control animals. The chemical nature of 

 these components is unknown at present. Examination of their 

 structure and identification by combined GC-MS is suggested for 

 further study. At present their structure and origin remains uncer- 

 tain. Many of the actual samples contain these components, but it is 

 difficult to ascribe their presence to recent incorporation of gasoline 

 due to their presence in the control. 



However, Table 2-6 represents an attempt at an objective 

 quantification of these compounds. Based on 1) the qualitative 

 scrutiny of the gas chromatograms and 2) quantitative values 

 higher than the control sample, five of the samples may contain 

 small amounts of gasoline components acquired from the spilled 

 gasoline. Without statistically rigorous measurements of control 

 levels of these components, we cannot be sure of a cause and effect 

 relationship concerning the component levels associated with those 



samples designated by "G" in Table 2-6. The "G" designations in 

 Table 2-6 reflect those samples having at least twice the control 

 levels of the measured components. 



Of perhaps equal interest is the presence of large quantities of 

 HMW petroleum compounds in four of the flounder samples, in- 

 cluding the control (Figs. 2-11, 2-12). The homologous series of 

 n-alkanes and the dominance of the unresolved "hump" are keys 

 to the HMW designation. Although not quantified, levels of HMW 

 are two orders or magnitude (10 2 ) higher than the gasoline concen- 

 trations observed. The possibility remains that the fish specimens 

 had depurated any assimilated gasoline during the 2-4 d period be- 

 tween the spill and when the fish were captured and frozen. 



Conclusions.— The processes of selective solubilization ana selec- 

 tive uptake of gasoline components complicates our ability to pre- 

 sent definitive "total gasoline concentrations." A more fruitful ap- 

 proach would be to focus on several key components — perhaps 

 alkyl benzenes— and to follow their incorporation into marine 



14 



