(clams and oysters) suggest that similar detoxification pathways are 

 not present in these less complex species. 



Since naphthalenes appeared to be important petroleum hydrocar- 

 bons from the standpoint of toxicity and tissue retention, the relation- 

 ship between exposure water and tissue naphthalenes concentrations 

 and respiratory response was investigated by the Texas A&M group. 

 The respiratory response of several species to oil exposure was evalu- 

 ated. The only species studied which consistently demonstrated ab- 

 normal oxygen consumption rates in response to exposure to oil was 

 the mysid Mysidopsis almyra. In this species oil exposure always re- 

 sulted in respiratory rates significantly higher than control values. 

 It is interesting that during exposure to both the WSFs (water soluble 

 fraction) and OWDs (oil- water-dispersal) of No. 2 fuel oil, the maxi- 

 mum respiratory rate occurred at an exposure concentration of 0.40 

 ppm total naphthalenes. 



An attempt was made in subsequent experiments to correlate ab- 

 normal respiratory responses to the concentration of oil-derived naph- 

 thalenes in the tissues of the experimental animals. When postlarval 

 brown shrimp Penaeus aztecus were exposed to a 30% WSF of No. 2 

 fuel oil for 4 hours, they accumulated high concentrations of naph- 

 thalenes in their tissues and had respiratory rates significantly higher 

 than those of controls. After a recovery period of 27 hours in oil free 

 sea water, the shrimp still contained approximately 6.2 ppm naphtha- 

 lenes and had respiratory rates still significantly above those of con- 

 trols. In another experiment, grass shrimp Palaemonetes pugio were 

 exposed to a dilute of No. 2 fuel oil OWD (0.10 ppm total naphtha- 

 lenes) for 5 hours. They accumulated approximately 2.0 ppm total 

 naphthalenes in their tissues and had respiratory rates which were 

 depressed to a level similar to that of animals which had been starved 

 for 48 hours. Seven days after exposure, the shrimp had released the 

 naphthalenes during maintenance and feeding in clean water and 

 their respiratory rates had returned to the control level. 



At the University of Texas the investigators have been studying the 

 effects of the water soluble components of petroleum oils and deriva- 

 tives on marine animals. A series of fuel oils, petroleum cuts, fractions 

 of No. 2 fuel oil and automotive oils have been examined. The main 

 emphasis has been on the aromatic components of the water soluble 

 fraction, and selected aromatics found therein have been tested in- 

 dividually. In these investigations both adult and early developmental 

 stages have been studied. It was expected that aquatic animals, during 

 the several stages of their life histories, would possess variable resis- 



30 



