title: A high throughput passive dosing format for the Fish Embryo Acute Toxicity test.
abstract: High throughput testing according to the Fish Embryo Acute Toxicity (FET) test (OECD Testing Guideline 236) is usually conducted in well plates. In the case of hydrophobic test substances, sorptive and evaporative losses often result in declining and poorly controlled exposure conditions. Therefore, our objective was to improve exposure conditions in FET tests by evaluating a passive dosing format using silicone O-rings in standard 24-well polystyrene plates. We exposed zebrafish embryos to a series of phenanthrene concentrations until 120h post fertilization (hpf), and obtained a linear dilution series. We report effect values for both mortality and sublethal morphological effects based on (1) measured exposure concentrations, (2) (lipid normalized) body residues and (3) chemical activity. The LC50 for 120hpf was 310μg/L, CBR50 (critical body residue) was 2.72mmol/kg fresh wt and La50 (lethal chemical activity) was 0.047. All values were within ranges expected for baseline toxicity. Impaired swim bladder inflation was the most pronounced morphological effect and swimming activity was reduced in all exposure concentrations. Further analysis showed that the effect on swimming activity was not attributed to impaired swim bladder inflation, but rather to baseline toxicity. We conclude that silicone O-rings (1) produce a linear dilution series of phenanthrene in the 120hpf FET test, (2) generate and maintain aqueous concentrations for reliable determination of effect concentrations, and allow for obtaining mechanistic toxicity information, and (3) cause no toxicity, demonstrating its potential as an extension of the FET test when testing hydrophobic chemicals.
authors.affiliation: Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium. Electronic address: lucia.vergauwen@uantwerpen.be.
authors.forename: Lucia
authors.initials: L
authors.lastname: Vergauwen
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Miljoevej 113, 2800 Kgs. Lyngby, Denmark.
authors.forename: Stine N
authors.initials: SN
authors.lastname: Schmidt
authors.affiliation: Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Stinckens
authors.affiliation: Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Walid
authors.initials: W
authors.lastname: Maho
authors.affiliation: Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
authors.forename: Ronny
authors.initials: R
authors.lastname: Blust
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Miljoevej 113, 2800 Kgs. Lyngby, Denmark.
authors.forename: Philipp
authors.initials: P
authors.lastname: Mayer
authors.affiliation: Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Adrian
authors.initials: A
authors.lastname: Covaci
authors.affiliation: Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Dries
authors.initials: D
authors.lastname: Knapen
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D057927:Hydrophobic and Hydrophilic Interactions; D007928:Lethal Dose 50; D010616:Phenanthrenes / Q000737:chemistry / Q000633:toxicity; D013550:Swimming; D023382:Toxicity Tests, Acute / Q000295:instrumentation* / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*; D015027:Zebrafish / Q000196:embryology*
chemical_list: D010616:Phenanthrenes; D014874:Water Pollutants, Chemical; C031181:phenanthrene
keywords: Acute toxicity; Critical body residue; Fish early life stages; Phenanthrene; Polycyclic aromatic hydrocarbon; Zebrafish embryo