Do DOM quality and origin affect the uptake and accumulation of lipid-soluble contaminants in coastal filter feeders? An experimental simulation of teflubenzuron exposure to blue mussels

Sabrina Schultze; Tom Andersen; Nina Knudtzon; Anders Ruus; Jan T Rundberget; Steven J Brooks; Amanda Poste; Dag O Hessen; Katrine Borgå

doi:10.1016/j.aquatox.2023.106696

Do DOM quality and origin affect the uptake and accumulation of lipid-soluble contaminants in coastal filter feeders? An experimental simulation of teflubenzuron exposure to blue mussels

Aquat Toxicol. 2023 Oct:263:106696. doi: 10.1016/j.aquatox.2023.106696. Epub 2023 Sep 25.

Authors

Sabrina Schultze¹, Tom Andersen², Nina Knudtzon², Anders Ruus³, Jan T Rundberget⁴, Steven J Brooks⁴, Amanda Poste⁵, Dag O Hessen², Katrine Borgå²

Affiliations

¹ Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway. Electronic address: sabrina.schultze@ibv.uio.no.
² Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway.
³ Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway; Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway.
⁴ Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway.
⁵ Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway; UiT-The Arctic University of Norway, Tromsø 9037, Norway; Norwegian Institute for Nature Research, Fram Centre for High North Research, Hjalmar Johansens gate 14, 9007 Tromsø, Norway.

PMID: 37757569
DOI: 10.1016/j.aquatox.2023.106696

Abstract

The increased export of terrestrial dissolved organic matter (terrDOM) to coastal marine ecosystems may affect local filter feeders and the local food web via the altered uptake of organic material and associated contaminants. To compare terrDOM to marine DOM (marDOM) as contaminant vectors to coastal biota, we exposed blue mussels (Mytilus sp.) to the different DOM types in combination with teflubenzuron, a widely applied lipophilic aquaculture medicine targeting salmon lice (Lepeophtheirus salmonis). A 16-day exposure of the blue mussels to DOM and teflubenzuron was followed by a depuration phase of 20 days without teflubenzuron. We calculated teflubenzuron adsorption rates and bioaccumulation factors (BAF) using a Bayesian model, expecting teflubenzuron uptake to be greater with terrDOM than marDOM due to the higher prevalence of large amphipathic humic acids in terrDOM. Humic acids have strong absorption properties and are able to envelope lipophilic molecules. Thus, humic acids can function as an efficient contaminant vector when taken up by filter feeders. Although there were varying degrees of overlap, the mussels tended to accumulate higher amounts of teflubenzuron in the DOM treatments than in the seawater control (bioaccumulation factor [BAF] in seawater: median 106 L/kg; 2.5 %-97.5 % percentile: 69-160 L/kg). Contrary to expectations, mussels exposed to marDOM showed a trend toward more bioaccumulation of teflubenzuron than those exposed to terrDOM (BAF marine 144 L/kg; 102-221 L/kg versus BAF terrestrial: 121 L/kg; 82-186 L/kg). The highest teflubenzuron accumulation was observed with the 50:50 mixture of marDOM and terrDOM (BAF mix: 165 L/kg; 117-244 L/kg). The slight difference in DOM-type accumulation rates observed in this experiment-especially the accumulation rate of terrDOM compared to that of the seawater-only treatment type-was not considered environmentally relevant. Further studies are necessary to see if the observed trends transfer to complex environmental systems.

Keywords: Bioaccumulation; Browning; Contaminant vector; DOM; Ecotoxicology; Humic acids; Mytilus spp; Teflubenzuron.