Formatted Title:

PCB Congeners for Aroclor Determination and Chemical Fingerprinting: Sediment Case Study

Background/Objectives:

Aroclor PCB analysis (USEPA 8082) has been around for decades and continues to be the default method used for environmental monitoring of PCBs. However, this method is now considered outdated analytically since advancements have made it feasible to measure and interpret individual PCB congeners. Furthermore, many environmental PCB sources are mixtures of commercial formulations, environmentally degraded products, or include non-Aroclor PCB sources, making reliance on Aroclor formulations potentially misleading.

This study aims to determine Aroclor mixtures using PCB congener data, allowing for accurate quantification of Aroclor equivalents. This approach facilitates long-term monitoring and identifies alternative PCB sources.

Approach/Activities:

PCB congener samples with prior Aroclor measurements using USEPA 8082 were processed through a chemometric workflow to visualize congener profiles, which were statistically compared to Aroclor commercial mixtures. The chemometric workflow was aimed at reducing the multi-dimensional PCB congener data to cluster the PCB fingerprints by similarity. Aroclor equivalents were calculated and compared against laboratory measurements using EPA Method 8082. Biases between the methods were analyzed, and non-Aroclor PCB sources present in samples were identified, which would not have been detected using Aroclor data alone. Additionally, receptor modelling was conducted on PCB congener data to apportion PCB sources and compare with calculated Aroclor equivalents and measured Aroclor concentrations.

Results/Lessons Learned:

Aroclor PCB concentrations can be accurately calculated from congener PCB data. These calculated Aroclor equivalent concentrations better represent the commercial PCBs in samples as congener analysis is less prone to interferences resulting from co-elutions. These interferences associated with laboratory Aroclor measurements overpredicted commercial PCBs compared to congener PCB data. The ability to detect alternative byproduct PCB sources further underscores the advantage of using PCB congener data for environmental PCB evaluation.

Mike Dereviankin

Affiliation

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(Group 1, Poster Board #15) PCB Congeners for Aroclor Determination and Chemical Fingerprinting: Sediment Case Study