Katrina Cavlek, Dag Ekeberg, Kenneth A. Kristoffersen, Fedor Kryuchkov and Roland Kallenborn
Faculty of Chemistry, Biotechnology and Food Science (KBM), Norwegian University of Life Sciences (NMBU), Ås,
Norway
Email: Katrina.cavlek@nmbu.no
Ciona intestinalis is a globally distributed tunicate and one of the closest living relatives to vertebrates1, widely used as a model organism in environmental toxicology and developmental studies2. Among the contaminants of concern in marine ecosystems, per- and polyfluoroalkyl substances (PFAS) which are synthetic compounds built on a carbon–fluorine backbone, known for their exceptional chemical stability and persistence3. Due to their resistance to degradation, high mobility, and bioaccumulative properties, PFAS have become globally recognized contaminants of concern with potential ecological and toxicological effects4.
This study investigates PFAS occurrence in C. intestinalis collected from four locations in the inner Oslofjord to evaluate variation and potential exposure levels. Samples were analysed using a modified EPA Method 1633 protocol coupled with LC–MS/MS. A range of perfluoroalkyl carboxylic acids (PFCAs) and sulfonic acids (PFSAs) were detected, with perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) as dominant compounds.
Figure 1. C. intestinalis adults. Photo credit: Morten Munthe (Marea).
The results revealed generally low PFAS concentrations across all sites, suggesting limited contamination within the inner Oslofjord. The consistency in PFAS profiles and the observed reduction in concentrations between sampling periods indicate stable accumulation dynamics and potentially decreasing environmental exposure. These findings support the use of C. intestinalis as a sentinel species for monitoring persistent pollutants while highlighting its potential role in mitigating PFAS levels through large-scale cultivation in eutrophic coastal areas.
(1) Brunetti, R.; Gissi, C.; Pennati, R.; Caicci, F.; Gasparini, F.; Manni, L. Morphological evidence that the molecularly determined Ciona intestinalis type A and type B are different species: Ciona robusta and Ciona intestinalis. Wiley Online Library: 2015; Vol. 53, pp 186-193.
(2) Wilson, E. R.; Murphy, K. J.; Wyeth, R. C. Ecological review of the Ciona species complex. The Biological Bulletin 2022, 242 (2), 153-171.
(3) Gaines, L. G. Historical and current usage of per‐and polyfluoroalkyl substances (PFAS): A literature review. American Journal of Industrial Medicine 2023, 66 (5), 353-378.
(4) Ahrens, L.; Bundschuh, M. Fate and effects of poly‐and perfluoroalkyl substances in the aquatic environment: A review. Environmental toxicology and chemistry 2014, 33 (9), 1921-1929.