The Decomposition of Crude oil Residues in Sand Columns

Abstract

The fouling of formerly clean sandy shores by the weathered residues of crude oil is all too familiar. Vigorous use of solvent emulsifiers can restore the beach ‘whiter than white’ but this damages the creatures which normally live in and on the sand. Unless the oil pollution is continual, the beach will usually rid itself of oil aided by waves and tides. Sometimes the disappearance of the oil may amount to no more than its bodily removal elsewhere or its burial out of sight, but inevitably, its ultimate destruction must be as the result of photochemical and biological processes. For intertidal sands where oil may become buried by wave action, the photochemical aspect is perhaps less important than for floating oil and the biological pathway is more important. In the experiments described here an attempt is made to investigate the rate of oil destruction by natural beach micro-organisms. Under the experimental conditions used, it is not difficult to sustain over a period of several months a fairly representative model of a beach with its populations of bacteria, diatoms and interstitial benthic animals.