CLARK and FINLEY: UPTAKE AND LOSS OF PETROLEUM HYDROCARBONS 



Figure l.-Tidal aquarium system showing the test and control tanks. 



the bottom of the sloping aquarium bottom, and 

 exposed to the tidal sweep of the oil floating on the 

 water surface. The second set was placed below the 

 extreme lower level of the tidal sweep so that the 

 organisms were continuously immersed in the 

 medium where they were exposed to dissolved and 

 emulsified fractions of the pollutant but never 

 physically covered with oil. 



During the experiment, a known volume of oil 

 was layered onto the 1,700 cm^ surface of the test 

 aquarium at "high" tide. The system was then 

 allowed to run through several complete tidal 

 cycles in an attempt to simulate the conditions 



Table 1.— Data on size of mussels, number of specimens, and 

 experimental conditions. 



which might be found under a pier or along a beach 

 following a significant oil spill. Two types of 

 refined products were used in the uptake studies, a 

 No. 2 heating fuel oil and a No. 5 heavy burner fuel 

 oil. 



At the end of the exposure, the bulk oil was 

 skimmed from the surface at "high" tide, and the 

 organisms were immediately placed in aerated 

 aquaria containing seawater medium. The water 

 was changed daily and the mussels fed a clam- 

 based diet three times a day (LaRoche et al. 1970). 

 Groups of the two sets of mussels were removed 

 from these aquaria for analysis 1, 7, 14, and 35 days 

 after the end of the exposure experiments. 



The paraffin hydrocarbon analysis techniques 

 for marine organisms have been described by 

 Clark and Finley (1973b). Mussels were sampled 

 and analyzed in groups of two to six individuals; 

 analysis was run on the combined tissue and body 

 fluids. No hydrocarbon content of the test 

 seawater medium nor of the clean seawater was 

 determined. Care was taken to minimize con- 

 tamination of the shucked meats from oil that 

 might have adhered to the shell, particularly in the 

 early samples (1 and 7 days). All results have been 

 reduced to "parts-per-million (ppm) dry extract- 



509 



