Molecular and isotopic identification of PAH sources in a highly industrialized urban estuary

Sources of polycyclic aromatic hydrocarbons (PAHs) in sediments in the Elizabeth River, VA, USA, a highly industrialized urban estuary, were examined using multiple source identification techniques. Large-scale historical creosote releases from former wood-treatment facilities had long been considered the dominant source of PAHs to the estuary. Employing principal component analysis (PCA) along with identification of source-specific isomer ratios, contributions from two former wood-treatment facilities were differentiated. Additionally, a significant coal contribution was determined by also incorporating compound-specific carbon isotope ratio analysis (CSIA). Use of CSIA also successfully isolated and separated the coal signature from a coal gasification signature, which could not be distinguished using only PCA and isomer ratios. The major contributors to sediment PAH contamination in the river were successfully identified, which included a former wood-treatment facility and historical and/or current coal transport and use, a source not considered in previous investigations.