Ecotoxicology

Brunel University has a long history of pioneering research in this field starting in 1978 when Prof. John Sumpter established a research group to examine environmental toxicology with particular emphasis on the causes and effects of endocrine disruption in aquatic wildlife.

Research began with the unexpected finding that male fish living downstream of sewage treatment works synthesise the egg yolk protein, vitellogenin (1). Further studies, involving the exposure of caged fish to various concentrations of sewage effluent, revealed that this occured in a dose dependent manner (2)(Fig.1).

This phenomenon has been studies in greater depth using a combination of laboratory and field-based approaches. For example, Dr Edwin Routledge has helped to develop a recombinant yeast strain that is genetically modified to respond to oestrogenic activity (Fig. 2). This has aided in the identification of many endocrine disrupting chemicals, which include both natural and synthetic hormones, as well as a range of industrial chemicals that induce oestrogenic effects (3). Extensive field studies have revealed further endocrine-mediated effects in fish such as intersexuality (4)(Fig.3). Recent research supervised by Dr Susan Jobling has associated this with reduced reproductive performance in terms of milt production, fertilisation rates and hatching success (5)(Fig.4), which has significant implications for populations of wild fish.

Recently the groups interests have been expanded to include amphibians, with the appointment of Dr. Dan Pickford, who is interested in the potential for endocrine disruption in this vulnerable wildlife group. To date his research has focussed on effects of xenoestrogens on female reproductive and endocrine function (6), and larval development and sexual differentiation in laboratory studies, and includes a fully GLP-compliant study required for EU chemical risk assessment (7). Dr. Pickford is currently extending his activities to field based studies to address the potential for effects of EDs and other contaminants in UK amphibians in the wild.

Current Work

Current projects include research into the mechanism(s) of action responsible for endocrine disruption, which includes the analysis of both oestrogenic and androgenic effects in fish. Research within the group also includes the study of a number of invertebrate species, the toxicology of which have been largely neglected to date. Other new and exciting areas of research include the development of transgenic fish and the study of pharmaceuticals in the environment.

Active Research Projects

• COMPRENDO - Comparative Research on Endocrine Disrupters
• A search for evidence of endocrine disruption of reproduction in top predator fish
• ACE - Assessing Combination Effects of Mixtures of Estrogenic Chemicals in Marine and Freshwater Organisms
• Zebrafish Transgensis: Application to Functional Genomics and Ecotoxicology Research
• Pharmaceuticals in the Environment
• Assessing the impact of endocrine disrupters in the aquatic environment on British Frogs and Toads, DEFRA (EDAQ program)
• Participation in OECD Phase Two Validation of Amphibian Metamorphosis assay for Thyroid Disrupters, DEFRA
• Functional genomics of ovulation in an amphibian model, Silurana tropicalis (Xenopus). Brunel Research Initiative and Enterprise Fund
• Characterisation and Functional Role of Novel Oestrogen Receptors in the Prosobranch Mollusc Marisa cornuarietis
• The effects of sewage pollution on Freshwater Molluscs
• Investigating the effects of pollution from commercial aviation activity on embryonic and larval development in common British anurans. Seed Grant from Declining Amphibian Populations Task Force