UPTAKE AND LOSS OF PETROLEUM HYDROCARBONS BY THE 

 MUSSEL, MYTILUS EDULIS, IN LABORATORY EXPERIMENTS 



Robert C. Clark, Jr., and John S. Finley' 



ABSTRACT 



Petroleum paraffin hydrocarbons (W-C14H30 to n-Cs'jK'je) from No. 2 and No. 5 fuel oils were rapidly 

 incorporated into the mussel, Mytilus edulis, in a laboratory system that simulated tides. The mussels 

 were exposed to levels of petroleum hydrocarbons from a surface slick similar to those encountered in 

 the environment after an oil spill. After 14 days in clean seawater, the mussels had lost most of the 

 hydrocarbons from the fuel oils; however, detectable traces of the No. 2 fuel oil still remained after 35 

 days. Preliminary results from these laboratory studies confirm previous studies of pollutant uptake 

 and loss following actual oil spills. 



Petroleum hydrocarbon uptake by the common 

 bay mussel, Mytilus edulis, can be readily deter- 

 mined in the laboratory with the analytical 

 chemical methods of solvent extraction, liquid- 

 solid, and gas-liquid chromatography. Mussels 

 lend themselves well to such studies because of 1) 

 their worldwide distribution and ready 

 availability (Davies 1969; Becker et al. 1973); 2) the 

 considerable amount of physiological base line 

 data available (Field 1922); 3) their hardiness as an 

 experimental test organism (GilfiUan 1973); 4) 

 their convenient size, which is small enough to 

 sample adequately and use in the laboratory 

 experimentally but large enough for specific organ 

 dissection (Lee, Sauerheber, and Benson 1972); 5) 

 their position in the intertidal ecosystem as a 

 major pathway for energy transfer utilizing phy- 

 toplankton and debris (Ricketts and Calvin 1962); 

 and 6) their known capacity for concentrating 

 various pollutants from their environment (Gref- 

 fard and Meury 1967; Modin 1969; Zitko 1970; 

 Clark and Finley 1973a). 



Earlier studies of hydrocarbon uptake and its 

 effects on marine organisms include those by 

 Griffith (1970) who determined the toxicity of 

 Arabian light crude oil and oil-dispersant mix- 

 tures on mussels under tidal conditions, and Lee, 

 Sauerheber, and Benson (1972) who used mineral 

 oil and radio-labeled ['^C] heptadecane to study the 

 laboratory uptake, body distribution, and loss of 

 hydrocarbons in mussels. We previously reported 

 on uptake of petroleum hydrocarbons by aquatic 



'Northwest Fisheries Center, National Marine Fisheries Ser- 

 vice, NOAA, 2725 Montlake Boulevard East, Seattle, WA 98112. 



organisms from several oil spills (Clark and Finley 

 1973a). This paper reports the findings of a 

 preliminary laboratory study using two refined 

 petroleum products, a No. 2 fuel oil and a No. 5 fuel 

 oil, in a laboratory system that simulates tidal ac- 

 tion. 



EXPERIMENTAL METHODS 



A tidal aquarium for laboratory studies of the 

 uptake and loss of petroleum by intertidal or- 

 ganisms has been described (Clark and Finley in 

 press) (Figure 1). This system consists of two 

 aquaria set at a 25° angle to represent a beach 

 surface. The first aquarium contained the or- 

 ganisms being exposed to the pollutant, and the 

 second aquarium, where all procedures were 

 duplicated except for the pollutant exposure, con- 

 tained control organisms. These control organisms 

 served as the base line comparison for mortality 

 studies and hydrocarbon analysis. The flood tide 

 was simulated twice a day by pumping an artificial 

 seawater medium (LaRoche et al. 1970) from a 

 carboy using a timer-equipped, variable-speed 

 pump. The ebb tide was accomplished by siphoning 

 the seawater medium back into the carboys from 

 beneath the surface oil slick in the test tank. Prior 

 to exposure, the mussels (collected in an area dis- 

 tant from known sources of petroleum pollution) 

 were acclimated to the tidal system for 24 h 

 following a previous 48- to 96-h conditioning in the 

 laboratory in an aerated aquarium (Table 1). 



In practice, usually two sets of test organisms 

 were used; one set was placed in the intertidal 

 zone, held by glass rods placed horizontally across 



Manuscript accepted September 1974. 

 FISHERY BULLETIN: VOL. 73, NO. 3, 1975. 



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