Age dating of environmental organic residues

The reformulated gasolines originating from these two refiners can be distinguished on this basis.The following case study illustrates the effectiveness of this method for fingerprinting gasoline: The objective of this investigation was to determine if a non-aqueous phase liquid (NAPL) encountered under a street separating two service stations was correlated to free-phase gasolines on either of the two adjacent service station properties.Significant advances have been made over the last fifteen years with regard to detailed compositional analysis of petroleum in the environment—often referred to as “chemical fingerprinting.” Some of the earliest applications of chemical fingerprinting were related to marine oil spills, e.g., grounding, in which knowledge of crude oil or residual fuel geochemistry was applied to identify and differentiate the spilled oil in Prince William Sound and assess its environmental impacts (e.g., Bence et al., 1996).In the past few years, continued developments in the chemical fingerprinting of refined petroleum products, such as gasoline and diesel fuel (Kaplan et al., 1997; Stout et al., 2002), have provided new tools for answering questions surrounding the source and/or age of contamination resulting from fugitive releases of petroleum (Beall et al., 2002; Kaplan, 2003).Chemical fingerprinting data must provide sufficient specificity to recognize the particular types of petroleum present at a site, characterize the effects of weathering on their chemical composition, and provide the diagnostic information necessary to distinguish and perhaps allocate between multiple sources of petroleum and assess their likely ages.For this reason, a “turnkey” analytical program that utilizes standard, regulatory methods for chemical analysis (e.g., U. Environmental Protection Agency (“EPA”) Methods 8015, 8020, 82, etc) usually does not produce the chemical detail needed to defensibly resolve environmental forensic questions.

Such a strategy allows for the quantitative measurement of a large number of gasoline-range (volatile) and diesel range (semi-volatile) hydrocarbons and non-hydrocarbons.Historic gasolines were blended primarily to achieve physical specifications for boiling range, vapor pressure, oxidation stability, and octane with the goal being suitable engine performance, such as starting under a range of temperatures, acceleration, knock, and resistance to vapor lock.How these physical specifications were achieved was largely left up to the individual refiners.Environmental forensic investigations typically address questions aimed at identifying the nature of contamination, its sources, and the timing of its release to determine the responsible parties.Definitive answers to these questions are not always achieved through forensic investigations, but combining chemical fingerprinting with other types of forensic data, including an understanding of the site-specific geologic and hydrogeologic conditions and operational and regulatory histories for the site, can produce highly effective and defensible arguments (Stout et al., 1998).

Leave a Reply

  1. hot sexy teen dating services 23-Feb-2018 21:15

    Our Ad Server is a solution that stores and delivers the right ads to the right sites in order to reach the right audience.