Testing for PAHs has improved using Sitelab’s new UVF-3100D analyzer, fitted with optical filters that are more selective to the PAH compounds reported by US EPA Method 8270 performed using GC/MS instrumentation.  The analyzer is calibrated using a PAH mixture containing the same compounds reported by the reference method. Sitelab's Target PAH concentrations correlate well to the sum of PAHs reported by Method 8270, which includes naphthalene, phenanthrene, benzo[a]pyrene and all the other PAHs added together, as illustrated below.

     Sitelab PAHs are performed to help monitor the progress of a bioremediation project by an environmental engineering firm.  The site is a former power plant located at a U.S. Air Force Base in Goldsboro, North Carolina.

     A contractor used Sitelab during a site assessment testing river sediments contaminated from a former manufactured gas plant in Colorado.  Like many MGP sites throughout the country, this site contains a subsurface plume of DNAPL oil, comprised of old coal tar, which sink in water, leftover from long ago.

    

     This time saving feature allows you to test samples for both PAH fractions at once, by rotating the optics from Slot A to Slot D and re-analyzing the sample. The ratios, or proportions, of a sample’s Total PAH and Target PAH results will vary depending on how old and what type of petroleum contamination exists.

Example:  Soil below a fuel oil tank once containing heating oil is 1,000 ppm EPH and 40 ppm Target PAH.  The drop in concentration is 25 times lower, indicating the spill is not fresh, but fairly weathered and degraded (see chart to right).

     The Target PAH optics are an integral part of Sitelab’s fluorescence fingerprinting method for hydrocarbon identification.  When used with the UVF-3100’s GRO analysis on the Slot B optics, requiring a separate calibration for testing the volatile C6-C10 BTEX fraction, the fluorescence signatures exhibited provides additional forensic screening data useful for delineating sites having unknown petroleum sources.

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