I am an environmental toxicologist and the AstraZeneca global lead for the development of innovative science to support future environmental risk assessments and secure the environmental safety (eco-toxicology) of pharmaceuticals; fundamental for sustainability.

As a comparative physiologist and expert fish biologist, I lead the mode-of-action driven investigations that provide a mechanistic understanding of how human pharmaceuticals may work in animals so as to better predict the possible risks to wildlife.

I am passionate about research to drive the aquatic safety testing paradigm away from animal studies. I do this by investigating new alternative approaches such as using cells to build 3D organoid tissues in culture. At AstraZeneca I am the global lead for the 3Rs (reduction, replacement and refinement) of animal studies and I am proud to chair the prestigious AstraZeneca awards that help share the innovation from these teams.

I am privileged to work with some of the leading academics and opinion formers in my field and have published more than 65 scientific papers. I work extensively supporting early career scientists and I am an Honorary Associate Professor in the College of Life and Environmental Sciences at the University of Exeter. In 2021 I joined the independent Hazardous Substances Advisory Committee for the UK Government, bringing expertise in New Approach Methods to support future chemical assessments.

By collaborating with some of the best scientists and leaders in academia, regulators and industry I am working towards finding better ways to predict the potential impacts of chemicals in the environment.

Stewart Owen Principal Environmental Scientist

Hon Associate Professor, University of Exeter.

Hazardous Substances Advisory Committee (HSAC)

Independent Member of UK Government Defra Advisory

AstraZeneca Council for Science and Animal Welfare


Principal Environmental Scientist


Invited to join the UK Government Defra Hazardous Substances Advisory Committee (HSAC) to share expertise in New Approach Methods to support future chemical assessments.


Published a book chapter on how to use artificial intelligence and machine learning innovations to better protect the environment from chemicals.


‘Prioritisation and Risk Evaluation of Medicines in the EnviRonment (PREMIER)’, a European Union Innovative Medicines Initiative (IMI) Joint Undertaking where I act as an industry lead and designated Ethics Officer.

Featured publications

Beyond the patient: Advanced techniques to help predict the fate and effects of pharmaceuticals in the environment.

Chapter 11 by Owen & Snape in: The Era of Artificial Intelligence, Machine Learning, and Data Science in the Pharmaceutical Industry. Academic Press, 2021, Pages 217-235, ISBN 9780128200452.


Pharmacology-informed prediction of the risk posed to fish by mixtures of non-steroidal anti-inflammatory drugs (NSAIDs) in the environment.

Marmon et al., 2021 Environment International 146, 106222


Vision of a near future: Bridging the human health–environment divide. Toward an integrated strategy to understand mechanisms across species for chemical safety assessment.

Rivetti et al., 2020 Toxicology in Vitro 62, 104692


Testing the translational power of the zebrafish: an interspecies analysis of responses to cardiovascular drugs.

Margiotta-Casaluci et al., 2019 Frontiers in pharmacology 10, 893


Pharmacology beyond the patient–The environmental risks of human drugs.

Gunnarsson et al., 2019 Environment International 129, 320-332


Prediction of bioconcentration factors in fish and invertebrates using machine learning.

Miller et al., 2019 Science of The Total Environment 648, 80-89


Machine learning for environmental toxicology: a call for integration and innovation.

Miller et al., 2018 Environmental science & technology 52 (22), 12953


A review of the pharmaceutical exposome in aquatic fauna.

Miller et al., 2018 Environmental Pollution 239, 129-146


The Use of Molecular Descriptors To Model Pharmaceutical Uptake by a Fish Primary Gill Cell Culture Epithelium.

Chang et al., 2018 Environmental science & technology 53 (3), 1576-1584


ECOdrug: a database connecting drugs and conservation of their targets across species.

Verbruggen et al., 2018 Nucleic acids research 46 (D1), D930-D936