Congener-specific PCB analysis by gas chromatography and a unique XRF method for fingerprinting asphalts were used to characterize a PCB-contaminated, coated corrugated metal pipe storm sewer buried under the Village of Brockport, NY. A recognized PCB-contaminated site was located directly upstream from the storm sewer inlet.

Former owners of the property argued that PCBs were in the “tar” pipe coating as manufactured given extensive use of PCBs in many applications prior to being banned. Analysis using USEPA SW-846 Method 8082, reporting PCBs as Aroclors, misidentified weathered PCBs in the coating as only Aroclor 1248, lending credence to the argument that the PCBs did not come from the upstream site, contaminated with Aroclors 1242 and 1260.

XRF fingerprinting definitively identified the "tar" coating as asphalt and demonstrated that asphalts on different sections of pipe installed over a 40+ year period could be distinguished from each other. XRF confirmed that the CMP sections were coated by the hot-dip process, resulting in the same asphalt applied to the interior and exterior of the pipe.

No PCBs were detected in the exterior asphalt coating, while all interior sections, including a section installed in the 1980's, long after the ban on PCBs, contained between 80-500 ppm PCBs. Congener-specific PCB analysis of the PCBs in several sections of pipe coating proved conclusively that the PCB contamination occurred as a result of an external, upstream source of PCBs flowing through the pipes, identical to those found on the contaminated property.