The fate of fresh and artificially weathered South Louisiana crude oil was investigated in large-scale experimental oil spills. The oil, originally introduced to the surface of a creek bounded by walls of transite (but open at subtidal level to allow communication with surrounding waters), was distributed by tidal action over a marsh of Spartina alterniflora. Samples of surface film, water, organic detritus, sediment, fish (Fundulus heteroclitus), oyster (Crassostrea Virginica), and clam (Mercenaria mercenaria) were collected over long periods and subjected to detailed chemical analysis by gas chromatography and computerized low resolution GC-MS techniques. Results are presented for water and Fundulus. Maximum concentrations of individual aromatic compounds found in fish were similar for both oils. This maximum occurred six hours after the spill for weathered crude, and 76 hours after the spill for fresh crude for all aromatic compounds except naphthalene and the methylnaphthalenes. Uptake appeared to be non-specific. In all cases investigated, hydrocarbon concentrations in animal tissue reached a maximum and then decreased to levels below measurability (<10 ppb). In the interpretation of the data, a distinction is made between environmental residence times observed in natural systems and the biological residence times measured in laboratory experiments.

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This paper deals with hydrocarbons in unconsolidated sediment and oysters, Crassostrea virginica, exposed to experimental oil spills. Quantitative data are based on high resolution, wall coated glass capillaries, and compound identification on mass spectrometry and retention. The results emphasize the general trends observed in Fundulus heteroclitus:3 a rapid response of individual tissue hydrocarbon concentrations to the spill, followed by a gradual decrease that appears to be related to the environmental residence time of the compound. Total aromatic concentrations in unconsolidated sediment (unresolved envelope + peaks), at the maximum, reach >500 parts per million (ppm) in both spill areas. In oyster tissue, maximum concentrations of total benzene eluate are <5 ppm and those of individual isomers in general are <100 parts per billion (ppb). Compositional changes with time are evident in both unconsolidated sediment and oyster extracts, resulting in increasing complexity that in the end becomes a basic limitation to analytical efforts for quantitation from gas chromatograms. Total concentrations of benzene fractions in oysters were found to remain essentially constant over a period of at least 10,000 hours; those of individual compounds clearly decay to ppb levels within a few hundred hours. Unconsolidated sediment extracts were found to contain chlorinated hydrocarbons in concentrations of the same order of magnitude as those of aromatic hydrocarbons. While a few chlorinated hydrocarbons were also detected in oysters, their concentration relative to aromatic hydrocarbons was low and their structure in general different from those in unconsolidated sediments. Contrary to expectations, there is no obvious correlation between unconsolidated sediment and oysters.