Using 14C Labeling in Ecotoxicology Assays to Ensure Relevance and Better Assess the Impact of PFAS in the Marine Environment
Craig Styan | University of South Australia
The objective of this project is to develop a methodology that can be used in ecotoxicological testing of per- and polyfluoroalkyl substances (PFAS) with marine organisms to ensure assays based on reproduction and early life history endpoints are relevant to real world scenarios. Thus far, there has only been a handful of ecotoxicology tests with PFAS and marine invertebrates, most of which have focused on endpoints based around reproduction or early larval survival (e.g., in mussels and sea urchins). Such endpoints are commonly used in marine ecotoxicology and will likely also be used in future tests with other species and PFAS. The duration of such tests, however, are short (ranging from hours to just a few days) and previously uncontaminated gametes or larvae are exposed to toxicants only for the duration of the test. Thus, depending on the uptake of specific PFAS into organisms, the level of PFAS experienced by larvae/gametes in an assay may underestimate the internal concentration of PFAS they would experience if spawned from parents who were previously exposed to the PFAS; consequently, such tests may underestimate toxicity. This project will assess the potential for such bias and determine how it might be avoided in future testing.
The approach will be to use 14C labeled PFAS as a surrogate to confirm nominal exposure concentrations and PFAS accumulation in a suite of common ecotoxicological assays based around reproduction and larval survival in marine invertebrates and macroalgae. The new approach will allow for quicker and cheaper confirmation of PFAS exposures in marine ecotoxicological testing generally and to assess whether assays based around reproduction and larval settlement/survival potentially underestimate toxicity because of the short exposure to PFAS during tests. Testing a series of five hypotheses, the project team will assess the uptake of three PFAS in three different types of ecotoxicology assay based on a) fertilizations and early larval survival in broadcasting spawning marine invertebrates or macroalgae, b) larval settlement, metamorphosis and early survival in brooding marine invertebrates, and c) reproduction in macroalgae.
Developing a methodology that will be adaptable for testing a range of PFAS on a diversity of algae and invertebrate species, this project will produce data that tests (and then accounts) for the potential artifacts caused by the short duration of reproductive tests, helping to develop more realistic toxicity reference values (TRVs). Specifically, perfluorooctanoic acid, perfluorohexanoic acid and perfluorobutyrate will be tested on several common, but hereto untested marine taxa, including a primary producer (green macroalgae) and secondary consumers/filter feeders including bryozoans and ascidians. Outcomes from this project will deliver fundamental information on the relevance of invertebrate and macroalgal reproduction and larval survival tests for deriving TRVs for PFAS in marine and coastal systems.