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GEOMATRIX Mr. Don O. Culbertson Chevron Pipe Line Company S March 1995 Page 3 t The WSF of fresh petroleum products and crude oil has been investigated at laboratory conditions using gas chromatography (GC) in a qualitative manner (Bruya and Friedman, 1992). The chromatograms produced during this study are provided as pairs; (a) of each pair is the GC trace of a fresh petroleum product and (b) of each pair is the GC trace of the WSF of the product in (a). The WSF of each pair was collected by obtaining a water sample in equilibrium with and immediately underneath the floating product. Note that the scale of the Y-axis is not consistent among all chromatograms (Figures la through 3b); this is not critical as this research was primarily qualitative. The first pair of GC traces shows a fresh crude oil and the WSF of the crude oil (Figures la and lb). The crude oil trace shows constituents that elute from about C, to C,0 (the limit for this GC column); the dominant peaks are the n-alkanes. The WSF of this crude oil is limited primarily to the low molecular weight alkanes (C, through Ch) and BTEX (C6 through C8), with very low concentrations of C9 through C„ constituents, most likely C9 and CIO monoaromatics and the smaller PNAs. The gasoline trace (Figure 2a) shows peaks that elute from approximately C, to C12. The WSF of this gasoline (Figure 2b) shows that the alkanes C, through C6, BTEX, alkylated benzenes (C9, CIO and C„), naphthalene (CIO), and methyl naphthalenes (CII) were detected. The diesel trace (Figure 3a) shows constituents that elute between approximately C6 and C24. The WSF of this diesel (Figure 3b) shows that the alkanes C4 through C6i BTEX, alkylated benzenes, naphthalenes, and phenanthrenes (C14) and anthracenes (C14) were detected. The WSF of fresh fuels in equilibrium with groundwater at laboratory conditions has been investigated in a quantitative manner by GC and GC/MS analyses (Thomas and Delfino, 1991). This research supports the qualitative findings of Bruya and Friedman (1992) and indicates that the WSF of the fuels tested includes the monoaromatics and the PNAs having 14 carbons or fewer (Table 1); the low-boiling alkanes were not included as target analytes in this study. These studies provide clear evidence that, at controlled laboratory conditions and when analyzed by standard commercial analytical methods, the detectable WSF of fresh crude oil and fresh fuels is limited to the low molecular weight alkanes ( C6), the monoaromatics, and the PNAs having 14 carbons or fewer. Under field conditions, however, the presence of phenanthrenes (C14) and anthracenes (C14) may not be detected at practical detection limits during routine analyses of environmental samples because of their very low concentrations and the probable lack of true equilibrium conditions.