The major objective of this project is the evaluation and validation of passive samplers capable of quantitatively pre-concentrating a wide range of per- and polyfluoroalkyl substances (PFAS) from surface water, groundwater, and porewater. Specifically, the project team will test three different passive samplers to determine dissolved concentrations of PFAS in different matrices, including groundwater, surface water (fresh and salt water), and porewater. Further, the project team will measure the fundamental physical-chemical properties of PFAS in water and sorbent, and will test each passive sampling approach for a wide range of target PFAS under various environmental conditions. The specific objectives are:

• Validate the agarose gel (AG) integrative passive sampler as a tool to determine dissolved concentrations of PFAS in various water matrices.
• Validate the graphene monolith (GM) equilibrium passive sampler for dissolved PFAS in surface water and porewater.
• Determine fundamental physical-chemical properties for PFAS in GM and AG samplers.
• Evaluate and compare different passive samplers for measuring PFAS in groundwater, surface water (fresh and salt water), and porewater.

The project objectives will be met by performing the following tasks:

• Tasks 1 & 2: Assess the AG and GM passive samplers to measure dissolved PFAS. Determine kinetic vs. equilibrium partitioning in samplers and variables affecting PFAS sampling rates.
• Task 3: Conduct laboratory experiments to determine:
  • molecular diffusion of PFAS in agarose gel passive sampler and water;
  • partitioning of PFAS in water-graphene and water-adsorbents (used in gel passive sampler construction) systems; and
  • the use of performance reference compounds.
• Task 4: Perform field-deployments of AG and GM passive samplers relative to polyethylene tube (PE) and the U.S. Geological Survey (USGS)-developed polar organic chemical integrative sampler (POCIS) to obtain sampling characteristics of individual PFAS in various water environments. The project team will leverage on-going trials of PE-tube samplers for comparison.

There are several expected benefits to DoD, site managers, and fellow scientists. First, the project team will develop and validate simple and reliable passive samplers that can be used by site managers and risk assessors to make informed decisions on the extent and magnitude of PFAS impact. Site managers and risk assessors need to know typical exposure concentrations to perform a sound risk assessment. The passive samplers will measure time-weighted average PFAS concentrations in water, which is highly relevant for exposure and risk assessment. Further, the ability to accurately measure truly dissolved concentrations is important to better characterize sorption and bioavailability, as they both relate to the chemical activity of PFAS. (Anticipated Project Completion - 2023)

Becanova, J., Z. Saleeba, A. Stone, R.H. Hurt, and R. Lohmann. 2021. A Graphene-Based Hydrogel Monolith with Tailored Surface Chemistry for PFAS Passive Sampling. Environmental Science: Nano, 8:2894-2907. doi.org/10.1039/D1EN00517K.

Glüge, J., R. London, I.T. Cousins, J. DeWitt, G. Goldenman, D. Herzke, R. Lohmann, M. Miller, C.A. Ng, S. Patton, X. Trier, Z. Wang, and M. Scheringer. 2021. Information Requirements Under the Essential-Use Concept: PFAS Case Studies. Environmental Science & Technology, 56(10):6232-6242. doi.org/10.1021/acs.est.1c03732. 

Snook, J., J. Becanova, S. Vojta, and R. Lohmann. 2023. Avoiding Artifacts in the Determination of Per- and Polyfluoroalkyl Substance Sorbent-water Distribution.  ACS ES&T Water, 3(8):2355–236. doi.org/10.1021/acsestwater.3c00084.