D. Mauro Presents two Courses in Environmental Forensics to the Massachusetts LSPA and the Connecticut EPOC
March and November, 2022
META Presents at the 8th International Symposium on the Redevelopment of Manufactured Gas Plant Sites - MGP 2019
PAHs in Urban Background: Ratios and Patterns
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.
Figure 1. Distribution of Fluoranthene/Pyrene Ratio in 418 Background Soil Samples
META was proud to Sponsor the 2019 10th Annual Oil Spill Symposium
Wednesday, May 8, 2019 | Great Hall, State Bar Center, Albany.
Hosted by the New York State Bar Association
Oil Spill Fund Update
Case Law Update
Gas Station Development, Redevelopment, and Due Diligence
Individual Liability & the Responsible Corporate Officer Doctrine
Petroleum Spill Case Study
META presents at Tenth International Conference on the Remediation and Management of Contaminated Sediments
February 13, 2019
DISTINGUISHING PYROGENIC PAH SOURCES IN SEDIMENT FROM MGP AND OTHER TAR SOURCES USING EXPLORATORY DATA ANALYSIS
Over the past 28 years, the laboratory at META Environmental, Inc. has analyzed many hundreds of tars and tarry materials from former manufactured gas plants (MGPs), coke plants, tar refineries, and related operations. A large subset of those data have been compiled and the trends in PAH distributions examined graphically, statistically, and with a variety of exploratory data analysis (EDA) techniques. For example, it was shown that tarry materials with very similar compositions could be distinguished using the appropriate chemicals and principal components analysis.
Figure 1. Principal components analysis (PCA) of 103 pyrogenic reference samples
Urban background is a ‘catch all’ term that includes a variety of sources of PAHs within urban environments. In sediment, urban background is commonly a mixture of petrogenic and pyrogenic PAHs; however, pyrogenic PAHs usually dominate. The chemical data from several sediment studies and from META’s tar reference archive were “mined” for characteristics and compounds and trends that help delineate former manufactured gas plant (MGP)-derived PAHs from general urban background. In addition to simple ratio approaches, multivariate exploratory methods, such as principal components analysis (PCA), cluster analysis, and positive matrix factor analysis (PMF) were used to identify and quantify differences between background patterns and the tar references. As with the tarry materials analysis (Figure 1), the data show that background can often be distinguished from tarry materials using the appropriate compounds and multivariate methods, even at relatively low concentrations.