Chemical Investigations of Two Experimental Oil Spills in an Estuarine Ecosystem, Part Ii

Abstract

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.

Potential Damage of Oil Wastes in Coastal Estuary Sediments1

“…3,8 ' n ' 12,10 The aromatic hydrocarbons obtained from these sites give further credence to a petroleum source in the sediments. 2 The most complete data were obtained at Chevron N. Dock nearest the refinery, where fluorescence and mass spectrometric data also confirm the presence of a number of polynuclear aromatic hydrocarbons (PNA) at >10 nanogram/gram levels. The aromatic chromatogram of this sample contained an array of PNAs similar to those of fresh crude oil giving firm evidence of a recent oil spill.…”