Laboratory‐Derived Bioaccumulation Kinetic Parameters for Four Per‐ and Polyfluoroalkyl Substances in Freshwater Mussels

Abstract

Although freshwater mussels are imperiled and identified as key conservation priorities, limited bioaccumulation information is available on these organisms for contaminants of emerging concern. In the present study we investigated the bioaccumulation of per-and polyfluoroalkyl substances (PFAS) in the model freshwater pond mussel Sagittunio subrostratus because mussels provide important ecosystem services and are important components of aquatic systems where PFAS occur. In the present study we selected four representative perfluorinated carboxylic acids and sulfonic acids, then determined the bioaccumulation kinetics of freshwater mussels in a controlled laboratory study. Because uptake (k u ) and elimination (k e ) rate constants and time to steady state are important parameters for food web bioaccumulation models, we derived bioaccumulation kinetic parameters following exposure to perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDA) at 10 µg/L and perfluoroundecanoic acid (PFUnDA) at 1 µg/L during a 14-day uptake period followed by a 7-day elimination period. Kinetic and ratio-based bioaccumulation factors (BAFs) were subsequently calculated, for example ratio-based BAFs for mussel at day 7 were determined for PFHxS (0.24 ± 0.08 L/kg), PFOS (7.73 ± 1.23 L/kg), PFDA (4.80 ± 1.21 L/kg), and PFUnDA (84.0 ± 14.4 L/kg). We generally observed that, for these four model PFAS, freshwater mussels have relatively low BAF values compared with other aquatic invertebrates and fish.

Bioaccumulation Kinetics of Model Pharmaceuticals in the Freshwater Unionid Pondmussel, Sagittunio subrostratus

“…Briefly, when the mixing tank was filled a siphon was created and delivered the premixed chemical and water to the exposure system at a regular interval. Additional details for the experimental system are provided elsewhere (Steevens et al, 2023). The system equilibrated for 7 days with control water, followed by an additional equilibration period of 48 h post chemical introduction of nominal concentrations of 5 µg L -1 acetaminophen and 1 µg L -1 sertraline, respectively, and prior to addition of organisms.…”