Analysis of Polycyclic Aromatic Hydrocarbon (PAH) Concentrations and Source Profiles from Sealcoated Pavements at Two Commercial Lots in Carlisle, Pennsylvania

Date of Award


Document Type

Honors Thesis



First Advisor

Amy E. Witter




Coal-tar-based sealcoats have been identified as a significant source of polycyclic aromatic hydrocarbon (PAH) pollutants. The concentrations and source profiles of PAHs in seal-coat samples from two commercial lots in Carlisle, Pennsylvania, were quantified. Seal-coat scrapings, from which a robust data set of PAHs was extracted (>1000 data points), were collected over approximately three-and-a-half months. PAHs were extracted from sealcoat emulsion samples, and the crude extracts were cleaned using solid-phase extraction prior to analysis using gas chromatography-mass spectrometry (GC-MS). Although samples from both sites exhibited similar PAH assemblages, the PAH profiles at each site varied temporally. Site A showed decreases in total PAH concentrations and low-molecular-weight-to-high-molecular-weight ratios; Site B's chemistry remained relatively static. Results suggest that different sealcoats used in Carlisle have diverse chemistries and varying cure times. Although a curing period of 24-48 hours is often recommended, curing times for sealcoats at the two Carlisle lots were found to last at least 41 days and even longer than 103 days.

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