PFAS: Smart Characterization for an Emerging Contaminant

The benefits of flux-based conceptual models derived from high-resolution site characterization are well understood for chlorinated solvents (CVOCs) and hydrocarbons. However, most practitioners are not aware that the approach can be used for emerging contaminants like per- and polyfluoroalkyl substances (PFAS). The introduction of a mobile laboratory capable of producing reliable PFAS results in hours instead of weeks has enabled us to conduct real-time characterization at PFAS sites for the first time. When combined with high resolution injection logging methods like the Hydraulic Profiling Tool (HPT), PFAS impacts can be mapped using a mass flux framework to identify key transport pathways that help focus extraction-based remedies.

The mobile PFAS laboratory (Pace Analytical Services, Inc.) uses a solid phase extraction sample prep technique followed by LC/MS/MS analyses that are based on EPA Method 537 (modified). The mobile lab is able to process up to 20 groundwater samples per day, which is sufficient to guide multiple drilling rigs and eliminate wasted borings and samples. This approach allows stakeholders to quickly understand the distribution of PFAS, and evaluate focused, efficient remedies – particularly important given the challenges associated with PFAS remediation. These concepts are illustrated using several case studies.