Per- and polyfluoroalkyl substances (PFAS) move through aquatic food webs, linking contaminated basal resources to invertebrates, fish, and human consumers. Yet predicting when and where PFAS propagate through food webs remains challenging because field exposure varies across resource types, abundance, and timing. Translating toxicokinetic rates from laboratory experiments to field conditions is particularly difficult because natural variability in exposure, chemical properties, and organismal traits can strongly influence observed concentrations and rate estimates. Our goal was to develop a quantitative bridge between laboratory toxicokinetics and field exposure by combining diet-based PFOS uptake and elimination rates with PFAS concentrations measured in basal food resources sampled opportunistically across Lake Michigan tributaries (biofilm, detritus, algae) as well as spawned salmon eggs which represent a seasonal, pulsed, resource subsidy that may alter PFAS exposures. Field concentrations were paired with laboratory-derived toxicokinetic parameters from dietarily exposed amphipods (Hyalella azteca). Amphipods were fed contaminated [~87 ng/g PFOS] benthic diatoms for 7 days followed by a 4-day elimination period with clean diatoms for food. In laboratory exposures, one-compartment models produced PFOS uptake rates of 0.095–0.150 d⁻¹ and elimination rates of 0.165–0.389 d⁻¹, yielding kinetics-based bioaccumulation factors (BAFkin = 0.39–0.58 kg kg-1) that indicate limited bioaccumulation under short-term diet-only exposure. We combined these empirically derived parameters with field-measured PFOS concentrations in basal and seasonal food resources to predict invertebrate body burdens from various diet types, including pulsed subsidy scenarios relevant to salmonid spawning events. This paired framework provides a novel quantitative link between field exposure measurements and food-web modeling to improve ecosystem-scale understanding of PFAS transfer.