O Methylnaphthalene 



A Dimethylnaphthalene 



O Fluoranthene 



• Anthracene 



en 



a. 



< 



cr 



UJ 



o 



z 

 c 

 o 



z 

 o 



CD 

 DC 

 < 



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Figure 11. — Decrease in concentration of petroleum 

 hydrocarbons added to CEPEX bags. 



and diatoms. 



In general, the lower alkyl phthalates, such as di-n-butyl 

 phthalate, produce more toxic effects than di-(2-ethyIhexyl)- 

 phthalate. Uptake studies with adult fish yielded low bioaccu- 

 mulation factors for the phthalates, relative to the chlorinated 

 hydrocarbons. One implication of this finding is that slow up- 

 take or rapid metabolism and excretion may be responsible for 

 the low toxicity of phthalates to higher organisms; this finding 

 would also explain the low levels present in biota samples from 

 the Gulf of Mexico. 



Experiments also focused on a characterization of the mixed- 

 function oxygenase (MFO) system in two marine invertebrates, 

 the blue crab and a polychaete worm. The MFO system is 



responsible for the metabolic modification of many foreign 

 compounds, such as hydrocarbons or pesticides, in animals. 

 Compared with the parent compound, the metabolite is more 

 water soluble and can be more easily excreted from the animal. 

 In the worm, enzyme activity was found in the lower intestine; 

 in blue crabs, activity was in the stomach and green gland. In 

 the blue crab, the enzyme activity of the green gland was found 

 to vary with different stages of maturity and molt cycle (fig. 13). 

 The green gland, generally thought of as an excretory organ, 

 may also function to regulate molting hormone levels. This may 

 explain the difficulty crabs and other crustaceans have in molt- 

 ing after exposure to certain pollutants. In worms continually 

 exposed to crude oil, we find higher levels of MFO after the 

 third generation. Thus, crude oil may influence development of 

 a genotype that is resistant to the effects of oil. 



In a similar study, MFO characteristics were studied in more 

 than 30 species of fish. Estuarine and coastal species (e.g., win- 

 ter flounder, two species of mummichogs, bluefish, striped bass, 

 menhaden, and mackerel) have moderate to high level of MFO 

 activity; however, the MFO properties of several of these spe- 

 cies show metabolic and inhibitor response characteristics that 

 are different from mammalian systems. On the other hand, 

 MFO activity in midwater, open-ocean fishes (e.g., viper fish 

 and hatchet fish), which was observed for the first time, was 

 generally very low compared to coastal species. 



In winter flounder and the mummichog, Fundulus hetero- 

 clitus, one or more properties of MFO were found to vary with 

 sex, season, or size. The observed patterns of variation confirm 

 that there are multiple forms of MFO systems within a given 

 fish species. 



In addition, the levels of MFO were consistently found to be 

 higher in estuarine fish from areas contaminated by organic 

 pollutants, including petroleum. For instance, fish from Wild 

 Harbor, Massachusetts, the site of a 1969 oil spill, are still 

 being affected 8 years after the spill. The results generally indi- 

 cate that while there may be a correlation between MFO activ- 

 ity and environmental contamination, the conditions under 

 which use of MFO as environmental indicators may be validly 

 interpreted are limited. 



Observations of the locomotor behavior of certain fish species 

 were made to determine the effect of short-term exposure to 

 increased but subacute concentrations of copper ions. Tempo- 

 rary exposure to increased copper levels drastically altered the 

 locomotor behavior of sheepshead fish. Overall activity was 

 greatly increased, and the pattern of movements in the tank, 

 which depends on the animal's turning behavior and is under 

 central nervous control, underwent distinct changes. Increased 

 activity was also observed in other fish species (spadefish, 

 triggerfish, pinfish, sea catfish, and croaker) exposed to increased 

 copper levels. 



Biological Effects Bibliography 



Anderson, J. W., D. B. Dixit, G. S. Ward, and R. S. Foster. 

 1977. Effects of petroleum hydrocarbons on the rate of heart 

 beat and hatching success of estuarine fish embryos. In: S. J., 

 Vernberg, A. Calabrese, F. P. Thurberg, and W. B. Vernberg 

 (editors), Physiological responses of marine biota to pollut- 

 ants, p. 241-258. N.Y. Acad. Sci., N.Y., N.Y. 



14 



