HRS Water Consultants
Ms. Armstrong is a Senior Project Engineer and a licensed Professional Engineer in the State of Colorado. She has consulted on a wide range of environmental contamination and remediation projects and litigation cases. After graduating with a Master’s Degree in Environmental Engineering from the University of Colorado, she built on her research as a graduate student in the design and development of in-situ groundwater remediation, including remedial optimization for groundwater plume management. Her technical experience includes site conceptual model development, data analysis and modeling, and planning and execution of complex site investigations.
No-Purge Groundwater Sampling For PFAS
Sampling groundwater for concentrations of per- and polyfluoroalkyl substances (PFASs) is challenging due to extremely low analytical reporting requirements in the part per trillion range, widespread historical occurrence of PFAS chemicals in consumer products including sampling equipment, and limited options for disposal of investigation derived waste. We report an ongoing pilot study at a PFAS site involving side-by-side comparisons of no-purge groundwater sampling versus low-flow sampling methods. The no-purge groundwater sampling method uses disposable, plastic PFAS-free bailers to grab groundwater samples at monitoring wells without a pre-purging step, also known as the “bailer-grab method.” During the pilot study duplicate groundwater samples were collected using a standard low-flow sampling method immediately after bailer-grabs were collected. Initial results are promising and demonstrate that bailer-grab results are consistent with low-flow results for all PFAS tested over three orders of magnitude in concentration. We also report our decontamination procedures and testing of sampling equipment.