FIELD EVALUATIONS OF NATURAL CHROMATOGRAPHIC SEPARATION AND RATIO ANALYSIS OF COMMON PETROLEUM CONSTITUENTS FOR PETROLEUM SOURCE IDENTIFICATION

Although ratio analysis has been used to differentiate or even age gasoline or diesel fuel petroleum hydrocarbon plumes, few case studies involving single, point source release scenarios in virgin settings are available to establish the reliance of these methods. Over 200 spill sites are currently under review to identify if they meet the criteria above. Of the initial 50 sites reviewed, data from five spill sites are presented herein. In each case, a gasoline surface spill occurred in an area that had (1) no history of petroleum usage, (2) relatively fast infiltration limiting the success of emergency response efforts, and (3) at least one year of groundwater monitoring prior to the commencement of groundwater remediation. The groundwater monitoring data along the primary groundwater flow path from each was evaluated by tabulating commonly used ratios. For the five spill sites, natural chromatographic separation of the BTEX compounds occurred along the primary flow path; however, the data also suggests that the use of various ratios for differentiating sources is limited. Of those ratios evaluated, only the ratio of benzene to xylenes (B:X) followed a relatively consistent trend for all five sites.