INTRODUCTION 



All fate and effects studies of oil spills in the marine environ- 

 ment depend on analytical chemical information concerning the distribu- 

 tion and composition of the spilled oil. This includes petroleum 

 hydrocarbon concentrations and compositions in water, sediment, and 

 tissue samples. In turn, this information can be used to deduce the 

 nature of the weathering process (including evaporation, dissolution, 

 and biodegradation) , biological assimilation and depuration, and the 

 mass budget of the oil. Thus the analytical chemistry component of the 

 AMOCO CADIZ research program provides crucial information to many 

 other components of the program in the investigation of the time- 

 dependent fate and effects of this spill. 



During the six weeks following the grounding of the supertanker 

 AMOCO CADIZ on March 16, 1978, oil came ashore along 320 kilometers of 

 the Brittany coastline (Gundlach and Hayes, 1978). Various shoreline 

 types were impacted (e.g., rocky shores, sand flats, coastal embay- 

 ments, tidal mud flats and salt marshes). During the early stages of 

 the spill, oil was transported offshore and deposited in the benthic 

 environment. The fate of petroleum residues deposited in these impact- 

 ed areas was and continues to be affected by coastal processes which 

 dictate such factors as wave energy and sediment transport, and create 

 environments of differing substrate character (e.g., grain size), 

 chemical status (oxidizing versus reducing) , and biological activity 

 (e.g., microbiological biomass) . All of these factors and others 

 (e.g., light intensity) combine to determine the weathering character- 

 istics of the residual petroleum assemblage. 



Biological populations initially impacted by the spilled oil may 

 be subject to chronic exposure to petroleum hydrocarbons associated 

 with (and released from) the substrate to which they are closely 

 linked, or they may undergo rapid or slow depuration of initial resi- 

 dues if no longer exposed to oil, via transplantation or due to flush- 

 ing by "clean" seawater. Such differential exposure histories have 

 been previously observed to profoundly affect the spilled oil residual 

 body burdens in marine organisms (Boehm et al., 1982). 



Although oil spills have received increasing attention from the 

 scientific community during the past decade, there have been few 

 opportunities to examine the chemical compositional changes in beached 

 or sedimented oil in a variety of coastal environments, over a signifi- 

 cant period of time and to examine uptake (impact) and depuration 

 (recovery) of petroleum by marine organisms. A detailed examination of 

 the chemical changes in oiled substrate suggests both the anticipated 

 residence time of deposited oil, and the potential for biological 

 damage of the petroleum residues. Rashid (1974) examined compositional 

 changes of Bunker C oil from the ARROW spill in Nova Scotia at dif- 

 ferent coastal locations. Other than this study only site-specific 

 studies of the geochemistry of petroleum weathering (e.g., Mayo et al., 

 1978; Blumer et al., 1973; Teal et al . , 1978) have been undertaken. 



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