Movement and identification of a creosote-derived PAH complex below a river pollution point source.

High pressure liquid chromatography was used to determine the identity of a black, oily leachate seeping into a spring-fed river. The leachate was identified as creosote by comparing a sample of the material to a sample of commercial creosote. As creosote contains a complex mixture of polynuclear aromatic hydrocarbons (PAH), the direct introduction of creosote into a stream system provided an opportunity to study the kinetics of these hydrocarbons as sediment contaminants below the creosote source. Concentrations of PAH, calculated on the basis of the amounts of organic matter contained in the sediments, declined rapidly below the point source in a form readily approximated by double exponential equations. An important aspect of the pattern of decline encountered was that concentrations tended to become asymptotic. As a result, the river's sediments became contaminated over a considerable distance.