EDCAT - Endocrine Disruption in Catchments
EDCAT: Background
Over the last few years, a series of international workshops, scientific groups and regulatory authorities has drawn attention to the fact that we are now beginning to understand some aspects of how endocrine disrupting substances (EDs), e.g. oestrogens and their mimics, act at the level of changes to the biochemistry, histology, morphology and physiology of aquatic organisms. However, we have little idea of the implications of these changes for wildlife populations and communities. We know, from the example of tributyltin-based antifouling paints and their interference with steroid metabolism in molluscs, that very serious ecosystem impacts can occur as a result of endocrine disruption, but we are not able to predict with confidence whether other types of endocrine disrupter pose similar threats.
Intersex roach testis, containing both oocytes and spermatozoa,
caused by exposure to environmental oestrogens
To some extent, this is a general ecotoxicological problem caused by our imperfect understanding of the way in which ecosystems work. The problem is highlighted by the case of oestrogenic endocrine disrupters which are causing feminisation (including intersexuality) of fish, and where regulatory authorities are facing and responding to public pressure to take precautionary action. Such action is justified by the scale of possible future damage (e.g. the potential collapse of many freshwater fish populations), and by the reasonable scientific expectation that oestrogens are indeed interfering with fish reproductive success in some cases. Possible actions have to be balanced against the enormous costs of remediating oestrogen-containing discharges. This balance is currently difficult to make because the extent to which reproductive success can be damaged without incurring adverse consequences for the population is poorly understood, and is likely to vary between species. Without a better understanding of the ecological benefits that are likely to flow from improvements in sewage effluent quality, it will remain difficult to convince dischargers to invest heavily in new plant.
As a consequence of these knowledge gaps, organisations and expert groups as diverse as the EU Scientific Committee on Toxicity, Ecotoxicity and the Environment (1999), the Environment Agency (2000), the European Workshop on Endocrine Disrupters (2001), the DEFRA Workshop on Future Research on Endocrine Disruption in the Aquatic Environment (2001), and DEFRA itself (CTG0301, 2003), have all called for research to investigate the ecological consequences of endocrine disruption at the level of populations and communities. Furthermore, several have advocated the study of these issues on the scale of whole river catchments, or at least of substantial sub-catchments, in order to obtain better information on the geographical extent of damage attributable to endocrine disruption.
EDCAT was therefore set up to address the as-yet unsolved problem of the degree to which feminised fish populations are at risk of long-term damage.
In vitro YES assay used for detecting oestrogenic activity
in environmental samples
References to work of EDCAT scientists in the field of endocrine disruption
This list includes both general review papers, and specific research papers addressing various aspects of exposure to, and effects of, endocrine disrupters in aquatic systems.
