A PRINCIPAL-COMPONENT AND LEAST-SQUARES METHOD FOR ALLOCATING POLYCYCLIC AROMATIC-HYDROCARBONS IN SEDIMENT TO MULTIPLE SOURCES

A method was developed to allocate polycyclic aromatic hydrocarbons (P AHs) in sediment samples to the PAH sources from which they came. The method uses principal-component analysis to identify possible sources and a least-squares model to find the source mix that gives the best f it of 36 PAH analytes in each sample. The method identified 18 possibl e PAH sources in a large set of field data collected in Prince William Sound, Alaska, USA, after the 1989 Exxon Valdez oil spill, including diesel oil, diesel soot, spilled crude oil in various weathering state s, natural background, creosote, and combustion products from human ac tivities and forest fires. Spill oil was generally found to be a small increment of the natural background in subtidal sediments, whereas co mbustion products were often the predominant sources for subtidal PAHs near sites of past or present human activity. The method appears to b e applicable to other situations, including other spills.