Biological Effects : Marine Animals 



A major goal of the Program is to determine the effects of sublethal 

 concentrations of pollutants on marine animals including sperm, eggs 

 and larvae. All investigators have found it necessary to establish lethal 

 levels for several organisms then to proceed to evaluate parameters 

 such as reproduction, growth and various physiological responses as 

 indicators of pollutant effects. The state of our knowledge does not 

 promise that mechanisms of uptake, toxic activity and detoxification 

 will be soon discovered. Several more immediate problems which can 

 be resolved include the relative sensitivity of larvae vs adults and 

 estuarine vs open ocean organisms for various pollutants. 



Heavy Hydrocarbons 



Texas A&M investigators have provided the Program with samples 

 of four American Petroleum Institute standard oils and their hydro- 

 carbon composition (Table 7). These data support the view of all in- 

 vestigators that the water soluble fraction of oil is of concern and 

 should be studied in depth. These oils and selected pure compounds 

 have been used by the Texas A&M group to determine the lethal con- 

 centration (96 hr. LC50) for a variety of organisms some of which are 

 given in Table 8. Test species were selected on the basis of their signifi- 

 cance in the food web, their diversity of taxa, their abundance in the 

 environment and their ability to survive, and in some cases reproduce 

 successfully in the laboratory. The experiments indicate that the high 

 aromatic #2 fuel oil and the Bunker C oil are the more toxic materials 

 (see also Anderson et al., 1974). In these studies there is a difference 

 of 2-3 orders of magnitude between adults and fry of Cyprinodon 

 variegatus. In nearly all cases, LC50 values are significantly higher 

 than levels of oil in the oceanic environment. However, in areas of oil 

 production or dumping and certainly in some estuaries these levels are 

 within the range encountered by animials. 



When exposed to dispersed #2 fuel oil in sea water, oysters rapidly 

 accumulated a wide spectrum of different hydrocarbons in experi- 

 ments carried out by Texas A&M investigators (Table 9) . The mono-, 

 di-, and tri-methylnaphthalenes were accumulated more than the 

 other di- and tri-aromatic hydrocarbons or individual paraffins. When 



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