Partitioning of no. 2 fuel oil in controlled estuarine ecosystems. Sediments and suspended particulate matter

To investigate the transport and incorporation of waterborne oil to sediments, no. 2 fuel oil was added as a dispersion in semiweekly doses to three controlled estuarine ecosystems. Samples of suspended particulate matter and sediments were analyzed by gas chromatography for saturated and aromatic hydrocarbons. Fractionation of the oil in the water column by adsorption to particulate matter resulted in the sedimentation of about 50% of the insoluble, saturated hydrocarbons, but less than 20% of the more soluble, aromatic hydrocarbons. The oil-derived hydrocarbons were slowly mixed down through the bioturbation zone. Biodegradation and other processes effected the removal of most of the hydrocarbons soon after the additions ended, but a residue of 10-20% in the form of branched alkanes, cycloalkanes, and aromatics in an unresolved complex mixture persisted more than 1 year later.