CLARK and FINLEY: UPTAKE AND LOSS OF PETROLEUM HYDROCARBONS 



48-h exposure plus 1 day in clean medium was 110 

 ppm. for the slick-exposed specimens compared 

 with only 29 ppm. for the submerged specimens. 

 Within 7 days the residual content had dropped by 

 nearly 75%, after which it declined at a slower rate 

 but was still significantly above background (8 

 ppm.) after 35 days in the slick-exposed specimens. 



No. 5 Fuel Oil Studies 



The residual paraffin hydrocarbon pattern 

 (Figure 8) for mussels exposed to a No. 5 fuel oil 

 revealed a definite uptake of pollutant hydrocar- 

 bons at the end of the 32-h exposure, and the 

 specimens collected 7 days later from clean 

 seawater medium contained less than 1 ppm. total 

 residual paraffin hydrocarbons attributable to the 

 pollutant (Figure 7). 



Gas-liquid chromatography of the saturated 

 hydrocarbon fraction of the exposed mussels 

 revealed a series of branched-chain hydrocarbons 



X CONTROLS 



EXPOSED -SURFACE SLICK 

 EXPOSED -SUBMERGED 





UJ 



a. 



Q. 



10 



15 20 25 30 35 



CARBON ATOMS /MOLECULE 



40 



from below C14 to C26, but of this series only pris- 

 tane was quantified and included in the calcula- 

 tions. Most unsaturated and aromatic compounds 

 were separated from the saturated fraction at the 

 silica gel/alumina column chromatography stage 

 without further analysis. 



DISCUSSION AND CONCLUSIONS 



These experiments, although preliminary in 

 nature, provide four basic conclusions: 1) mussels 

 rapidly took up pollution hydrocarbons during ex- 

 posure; 2) mussels lost pollution hydrocarbons 

 when removed from the test tanks and held in 

 clean seawater (depuration), but significant quan- 

 tities of No. 2 fuel oil remained for 35 days; 3) the 

 w-paraffin residual pattern (exposed levels minus 

 control levels) established for the exposed mussels 

 nearly duplicated the shape of the pollutant 

 hydrocarbon pattern; and 4) these laboratory 

 results confirmed analyses made on shellfish 

 following actual oil spills in the marine environ- 

 ment. 



O O 48-H AGED NO. 2 FUEL OIL 



X X EXPOSED TO SURFACE SLICK 



I DAY AFTER REMOVAL 



9 

 ■o 



V 



>, O 



o 



a. a. 



a. Q- 



v> _i 



2 — 



UJ o 

 u 



UJ 



a. 



EXPOSED TO SURFACE SLICK 

 7 DAYS AFTER REMOVAL 



15 20 25 30 35 



CARBON ATOMS / MOLECULE 



40 



Figure 4.-ParafRn hydrocarbon patterns in mussels exposed to a 

 No. 2 fuel oil: 1 day after removal. 



PiGUSE 5.-Residual paraffin patterns of mussels exposed to a No. 

 2 fuel oil: 1 and 7 days after removal. 



511 



