Pelagic embryos of fish may be exposed to high doses of natural UV radiation. Shortwave UV, UVB, as well as UVA may penetrate the water column to depths of several meters. The penetration depth differs depending on the contents of particles, dissolved matter or pollutants. Pollutants may also interact photochemically with UV- and visible radiation.
The aim of this study was to establish the dose-effect relationship of phenotypic changes caused by UV in order to plan further multistressor studies including ionising radiation. A modification of the antioxidant defence was studied by adding a methacrylate that was previously found to decrease the amount of glutathione in cells .
The zebrafish embryo test  was applied to score toxic effects of UVA and UVB. Embryos were treated in the period including mid- to late blastula stage, i.e. until 5 hours post-fertilisation. Radiation exposure was performed with a modified polymerisation unit equipped with various broadband fluorescent units with UVC filter.
The broadband UVB source was approximately 1000 times more effective in inducing morphological lesions and embryo death of the exposed embryos than was the UVA source. Comparison with published action spectra indicates that DNA damage may be a major factor in the pathway leading to the observed effects.
Hydroxyethylmethacrylate increased the UVB-induced effects on the embryos significantly. This finding indicates that synergistic effects may be induced if UV radiation and chemical pollutants interact in the environment.
This work was partly supported by the Research Council of Norway through its Centres of Excellence funding scheme, project number 223268/F50.
 T. Christensen, E. Bruzell, Photochem. Photobiol. Sci., 2010, 9, 1597.
 OECD Test Guideline (TG) 236, Fish Embryo Acute Toxicity (FET) Test, 26 July 2013
Ultraviolet Radiation and Multiple Stressor Effects on Zebrafish Embryos
Christensen T, Aleksandersen TB, Aleström P, Lyche JL, Bruzell EM
The 16th International Congress of Photobiology, Córdoba, Argentina, September 8-12, 2014. Book of Abstracts (A)