2.4 Chemical Analyses of Fish Samples 



This section was prepared by P. D. Boehm" and J. E. 

 Barak." 



Collection procedures. —A total of five 30 min groundfish 

 trawls were made on 18 and 20 March 1978, using a 12 m net (Table 

 1-2). The doors crossed on one trawl so no sample was obtained. 

 Fish and invertebrates were sorted at each station, identified to 

 species, and were frozen for hydrocarbon analyses (Table 1-3). 



Analytical procedure. — The fish were in good condition and 

 remained frozen until tissue preparation was begun. Each in- 

 dividual fish was filleted and the sample obtained from a combina- 

 tion of the skin, adipose tissue, and muscle. The samples were cut 

 into small pieces and wet weight (25-125 g) obtained (a subsample 

 was kept for dry weight determinations). The weight range was due 

 to both the size of the specimens and the number of individuals 

 comprising each sample. The tissues were then digested in 0.3 N 

 KOH-methanol in a screw-capped flask. The digestion mixture was 

 covered with a layer of 25 ml pentane (Resi-Analyzed, Baker). The 

 tissues were digested for 48 h on a shaker table after which time the 

 mixture was extracted three times with pentane. The combined pen- 

 tane extracts were concentrated down to 0.5 ml, and this volume 

 was passed through a clean-up column of fully activated silica gel to 

 remove polar lipid material. After eluting the column with 5 ml 



"Energy Resources Company, Inc., 185 Alewife Brook Parkway, Cambridge, 

 MA 02138. 



pentane, the eluate was concentrated under purified nitrogen to 50 

 Ml- 



One microliter out of 50 was injected into a Hewlett Packard 

 5840A gas chromatograph equipped with a spitless injector system 

 linked to a 15 m SE-30 glass capillary (WCOT) column. The oven 

 was held at 30 °C for 15 min and then temperature programmed at 

 2*C/min to an upper temperature of 260 °C. Peaks in the gasoline 

 range were integrated directly by the gas chromatographic 

 microprocesser. 



Concentrations were determined by comparison of the total 

 area of the sample peaks in the gasoline range to that in a tissue 

 spike of the combined cargo (Fig. 2-10). One microliter of a com- 

 bination of the five cargos was spiked to fish tissue, and the spiked 

 sample was carried through the entire procedure. Recovery of the 

 spike was 95% relative to a direct injection of the cargo mixture on 

 the gas chromatograph. To check on the possibility of evaporative 

 losses in the sample concentration (evaporation) steps, a spike was 

 administered to 25Q ml CHC1 ; and the spikes solvent evaporated to 

 50 /ul , first by rotary evaporation and finally by careful use of a 

 purified nitrogen stream. Losses by evaporative concentration were 

 negligible. Therefore, the quantification procedure which was based 

 on the detector response of an injection of a known volume of the 

 recovered cargo spike was a valid and reproducible method. 



Results. — The gas chromatogram of the spiked fish tissue 

 (Fig. 2-10) illustrates those components whose quantifications were 

 the analytical objective of this study. All samples contained some 

 higher molecular weight (HMW) hydrocarbon material. This is 

 especially evident in the control sample (Fig. 2-10) and in other 

 samples so designated in Table 2-6. The chemical nature of this con- 



Table 2-6. — Data summary of hydrocarbon analysis of fish samples collected near the site of the 

 Ocean 250 grounding. Samples designated G had at least twice the control levels of measured com- 

 ponents in the gasoline range. Those samples designated HWM had higher molecular weight 

 petroleum components. 









Concentration of 











components in 











gasoline range 











from Figure 2-10 









Days 



(mg/g dry 





Sample 



Station 



after spill 



weight of tissue) 



Designation 



Xfacrozoarces americanus 



12 



+ 2 



0.4 





Scophthalmus aquosus 



12 





0.5 





Pseudopleuronectes americanus 



12 





2.4 



G 



Limanda ferruginea 



12 





1.9 



G 



Raja erinacea 



12 





0.2 





Myoxocephalus octodecemspinosus 



12 





0.5 





Tautogolabrus adspersus 



12 





0.6 





Gadus morhua 



12 





1.1 





Macrozoarces americanus 



15 





1.7 



G 



Scophthalmus aquosus 



15 





0.6 



HMW 



Limanda ferruginea 



15 





0.6 



HMW 



Macrozoarces americanus 





+ 4 



1.6 



G 



Scophthalmus aquosus 







0.5 





Pseudopleuronectes americanus 







0.5 





Limanda ferruginea 







0.3 



HMW 



Raja erinacea 







1.1 





Macrozoarces americanus 



10 





1.0 





Scophthalmus squosus 



10 





0.2 





Pseudopleuronectes americanus 



10 





0.7 





Raja erinacea 



10 





0.2 





Hemitripterus americanus 



10 





1.3 





Clupea harengus 



10 





1.9 



G 



Pseudopleuronectes americanus 











Control 







0.7 



HMW 



Blank 







0.0 





13 



