Stefan Örn

Stefan Örn


I am a researcher in aquatic ecotoxicology. The aim of my research is to increase the knowledge of harmful effects of environmental pollutants on aquatic animal health. This is performed both by applied field research and effect-based laboratory studies. The laboratory studies include both in vivo and in vitro fish models for determination of toxicological effects on embryological development, sexual differentiation, reproduction, and behavior. The applied research include field studies and in situ field experiments, such as on-site studies at sewage treatment works. I have been involved in several projects regarding evaluation of different sewage treatment techniques in order to reduce the release of chemicals into the environment, including pharmaceuticals and human pathogens. Part of the research has also been working with regulatory aspects of toxicological assessment, such as development of standardized toxicity tests for evaluating endocrine disrupters in both fish and snails within OECD. Much of my research has been focused on endocrine disrupting chemicals that alter the function of the reproductive and endocrine system in fish. My current research areas also include studies of emerging contaminants and micropollutants (e.g. PFAS, pharmaceuticals), wastewater treatment technologies, and antibiotic resistant bacteria and pathogens in wastewater effluents and recipients.



Current projects:

Using the zebrafish embryo test (ZFET) as an alternative model for assessing bioconcentration in fish (PI Stefan Örn, Formas Research Council 2020-2022)

Risk modeling of mixtures of endocrine disrupting chemicals relevant to human exposure, using zebrafish (Danio rerio) embryo as model organism (RiskMix) (PI Jana Weiss, Formas Reseach Council 2019-2023)

Environmental hazard assessment of per- and polyfluoroalkyl substances (PFAS) using a tiered testing strategy (PI Stefan Örn, Formas Research Council 2018-2020)

Screening of antibiotic resistant bacteria (PI Stefan Örn, Swedish EPA 2017-2019)

New in vitro models for studying effects of environmental pollutants on early embryo development (PI Ylva Sjunnesson,, The Swedish Research Council 2018-2020)

Intersex in wild roach (Rutilus rutilus) from Swedish waters (PI Stefan Örn, SLU FoMA)

Fish health in domestic and industrial STW recipients (PI Stefan Örn, SLU FoMA)

Antibiotic resistant bacteria and pathogens in domestic STW effluents (PI Stefan Örn, SLU FoMA)


MSc (Fil.mag) Biology 1996, Uppsala University
The impact of an orally administered mixture of selected PCBs on reproduction in zebrafish

PhD Pathobiology/aquatic ecotoxicology 2006, Department of Biomedical Sciences and Veterinary Public Health, Veterinary Faculty, SLU
The zebrafish as a model organism for evaluation of endocrine disrupters

Associate professor Aquatic ecotoxicology 2019

Publikationer i urval

Menger F, J Pohl, L Ahrens, G Carlsson, S Örn (2020) Behavioural effects and bioconcentration of per-and polyfluoroalkyl substances (PFASs) in zebrafish (Danio rerio) embryos. Chemosphere 245:125573

Pohl J, O Golovko, G Carlsson, J Eriksson, A Glynn, S Örn, JM Weiss (2020) Carbamazepine Ozonation By-Products: Toxicity in Zebrafish (Danio rerio) Embryos and Chemical Stability. Environmental Science & Technology (in press)

Pohl J, L Ahrens, G Carlsson, O Golovko, L Norrgren, J Weiss, S Örn (2019) Embryotoxicity of ozonated diclofenac, carbamazepine, and oxazepam in zebrafish (Danio rerio). Chemosphere 225:191-199

Örn S, LL Fernström, O Golovko, L Ahrens, I Hansson, S Frosth (2019) Screening of faecal bacteria and antibiotic resistance in urban wastewater and recipient river surface water (

Pohl J, B Björlenius, T Brodin, G Carlsson, J Fick, DGJ Larsson, L Norrgren, S Örn (2018) Effects of ozonated sewage effluent on reproduction and behavioral endpoints in zebrafish (Danio rerio). Aquatic toxicology 200:93-101

Örn S, H. Holbech, L. Norrgren (2016) Sexual disruption in zebrafish (Danio rerio) exposed to mixtures of 17a-ethinylestradiol and 17b-trenbolone.  Environmental Toxicology and Pharmacology 41:225–231

Ulhaq M, M Sundström, P Larsson, J Gabrielsson, Å Bergman, L Norrgren, S Örn (2015) Tissue uptake, bioconcentration and elimination of 14C-PFOA in zebrafish (Danio rerio). Aquatic Toxicology 163:148–157

Carlsson G., S. Örn, DGJ. Larsson (2009) Effluent from bulk drug production is toxic to aquatic vertebrates. Environmental Toxicology and Chemistry, 28 (12):2656-2662

Örn S., S. Yamani, L. Norrgren (2006) Comparison of vitellogenin induction, sex ratio and gonad morphology between zebrafish and Japanese medaka after exposure to 17α-ethinylestradiol and 17β-trenbolone. Archives of Environmental Contamination and Toxicology 51:237-243

Örn S., A. Svenson, T. Viktor, H. Holbech, L. Norrgren (2006) Male-biased sex ratios and vitellogenin induction in zebrafish (Danio rerio) exposed to pulp mill effluent. Archives of Environmental Contamination and Toxicology 51:445-451

Örn S., H. Holbech, T.H. Madsen, L. Norrgren, and G.I. Petersen (2003) Gonad development and vitellogenin production in zebrafish (Danio rerio) exposed to ethinylestradiol and methyltestosterone. Aquatic Toxicology 65:397-411

Svenson A., S. Örn, AS. Allard, T. Viktor, J. Parkkonen, L. Förlin, L. Norrgren (2002) Estrogenicity in domestic and industrial effluents in Sweden. Aquatic Ecosystem Health & Management 5(4):423-434


Publication list at Google Scholar


Forskare FLK vid Institutionen för biomedicin och veterinär folkhälsovetenskap (BVF); Enheten för farmakologi och toxikologi
Telefon: +4618673486
BVF, Avd för farmakologi och toxikologi, Box 7023
Besöksadress: Ulls väg 26, Uppsala