Impacts of divalent cations (Mg2+ and Ca2+) on PFAS bioaccumulation in freshwater macroinvertebrates representing different foraging modes

Asa J Lewis; Xiaoyan Yun; Max G Lewis; Erica R McKenzie; Daniel E Spooner; Marie J Kurz; Rominder Suri; Christopher M Sales

doi:10.1016/j.envpol.2023.121938

Impacts of divalent cations (Mg²⁺ and Ca²⁺) on PFAS bioaccumulation in freshwater macroinvertebrates representing different foraging modes

Environ Pollut. 2023 Aug 15;331(Pt 2):121938. doi: 10.1016/j.envpol.2023.121938. Epub 2023 May 30.

Authors

Asa J Lewis¹, Xiaoyan Yun², Max G Lewis³, Erica R McKenzie², Daniel E Spooner⁴, Marie J Kurz⁵, Rominder Suri², Christopher M Sales⁶

Affiliations

¹ Department of Civil, Architectural, and Environmental Engineering, Drexel University, 3100 Market St., Philadelphia, PA, 19104, USA. Electronic address: ajl394@drexel.edu.
² Civil and Environmental Engineering Department, Temple University, Philadelphia, PA, 19122, USA.
³ Department of Biology, Temple University, Philadelphia, PA, 19122, USA.
⁴ Department of Biology, Commonwealth University of Pennsylvania, Lock Haven University, Lock Haven, PA, 17745, USA.
⁵ Academy of Natural Sciences of Drexel University, Philadelphia, PA, 19103, USA; Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
⁶ Department of Civil, Architectural, and Environmental Engineering, Drexel University, 3100 Market St., Philadelphia, PA, 19104, USA.

PMID: 37263566
DOI: 10.1016/j.envpol.2023.121938

Abstract

Per- and polyfluoroalkyl substances (PFAS) have extensively contaminated freshwater aquatic ecosystems where they can be transported in water and partition to sediment and biota. In this paper, three freshwater benthic macroinvertebrates with different foraging modes were exposed to environmentally relevant concentrations of eight perfluoroalkyl carboxylates (PFCA), three perfluoroalkyl sulfonates (PFSA), and three fluorotelomer sulfonates (FTS) at varying divalent cation concentrations of magnesium (Mg²⁺) and calcium (Ca²⁺). Divalent cations can impact PFAS partitioning to solids, especially to sediments, at higher concentrations. Sediment dwelling worms (Lumbriculus variegatus), epibenthic grazing snails (Physella acuta), and sediment-dwelling filter-feeding bivalves (Elliptio complanata) were selected due to their unique foraging modes. Microcosms were composed of synthetic sediment, culture water, macroinvertebrates, and PFAS and consisted of a 28-day exposure period. L. variegatus had significantly higher PFAS bioaccumulation than P. acuta and E. complanata, likely due to higher levels of interactions with and ingestion of the contaminated sediment. "High Mg²⁺" (7.5 mM Mg²⁺) and "High Ca²⁺" (7.5 mM Ca²⁺) conditions generally had statistically higher bioaccumulation factors (BAF) than the "Reference Condition" (0.2 mM Ca²⁺ and 0.2 mM Mg²⁺) for PFAS with perfluorinated chain lengths greater than eight carbons. Long-chain PFAS dominated the PFAS profiles of the macroinvertebrates for all groups of compounds studied (PFCA, PFSA, and FTS). These results indicate that the study organism has the greatest impact on bioaccumulation, although divalent cation concentration had observable impacts between organisms depending on the environmental conditions. Elevated cation concentrations in the microcosms led to significantly greater bioaccumulation in the test organisms compared to the experimental reference conditions for long-chain PFAS.

Keywords: Bioavailability; Environmental relevance; Fate and transport; PFAS profiles; Uptake mechanism.

MeSH terms

Alkanesulfonates
Bioaccumulation
Carboxylic Acids
Cations, Divalent
Ecosystem
Fluorocarbons* / analysis
Fresh Water
Water
Water Pollutants, Chemical* / analysis

Substances

Cations, Divalent
Water Pollutants, Chemical
Fluorocarbons
Alkanesulfonates
Water
Carboxylic Acids