PAHs in Urban Background: Rations and Patterns
David Mauro, President, META Environmental, Inc.
Recently, Mr. Mauro presented the results of analyses of tars and tarry materials from former manufactured gas plants, coke plants, tar refineries, and related operations to identify chemical patterns with the greatest forensic value. It was shown how tar formation conditions affect the composition of byproducts of these operations and how the patterns in those byproducts could be used for source identification. Previous presentations focused on pyrogenic, high polycyclic aromatic hydrocarbon (PAH) concentration substances only. However, it has long been recognized that PAHs are nearly ubiquitous at low to moderate concentrations in urban surface soils, and that the PAHs generally originated from both pyrogenic and petrogenic sources. Two studies of PAHs in urban surface soil in the United States were completed by META Environmental, Inc. for the Electric Power Research Institute and the Gas Research Institute. Surface soil samples from over 500 sites in 42 population centers in four states were collected and analyzed for PAHs; this represents the most comprehensive study of PAHs in urban surface soil available. The samples were analyzed for GC/FID fingerprints and 40 PAHs and alkylated PAHs by GC/MS. The chemical data from the background PAH study were “mined” for additional characteristics and compounds and trends that help delineate former manufactured gas plant (MGP)-derived PAHs from general urban background. The study data indicated that much, if not all, of ambient PAHs in soil are from non-MGP-sources. The findings of the data mining exercise will be summarized and chemical characteristics, such as PAH patterns and co-contaminants, with the greatest forensic value will be highlighted.
Mr. Mauro is an environmental and analytical chemist with more than 30 years of experience in the field. He is co-founder and president of META Environmental, Inc. (META), a nationally-recognized environmental consulting company. Mr. Mauro has served as the project manager or senior technical consultant for dozens of projects involving design and implementation of site characterization, source identification and cost allocation, treatability studies, environmental fate and transport, statistical and quality control assessments, and remedial designs under CERCLA, RCRA, and other programs.