Unmixing of PAHs in Contaminated Sediments Using Positive Matrix Factorization

Abstract

Abstract One of the challenges to apportioning PAH-related remedy costs at contaminated sediment Sites is unmixing of PAH fingerprints to PAH source classes (petrogenic, pyrogenic, and runoff, a derivative of petrogenic and pyrogenic sources). Unmixing of PAHs can be challenged by lack of source samples, different PAH signatures associated with different sources (or sometimes the same source), historical PAH sources long removed, urban sediment movement by boat traffic and, in turn, PAHs mixing, and weathering effects on PAH fingerprints. This work demonstrates using Positive Matrix Factorization (PMF) as a method to unmix PAH fingerprints to its source classes, while overcoming these challenges. A large PAH dataset (over 700 samples) assembled from contaminated urban sediment sites was used as an input to PMF. Using a 3-Factor PMF analysis, a petrogenic, pyrogenic, and runoff/weathered PAH end member fingerprints were identified. Different numerical mixing percentages of the PMF-identified end member sources were able to replicate the site-measured PAH fingerprints, with the percent contribution of each of the end members to each sediment sample calculated. In addition, the analysis calculated the percent contribution of each end member source to each PAH compound (e.g., benzo([a]pyrene). The demonstrated work provides a method to satisfy the unmixing of PAH fingerprints to its source classes, as a step towards apportioning of PAH contamination.