The primary objective of the EDCAT programme
(Phase 1, 2006-2008) is to investigate whether the endocrine disruptors (EDs) present in a large sewage discharge (Swindon Rodbourne STW discharging to the River Ray in Wiltshire, UK) scheduled for remediation in 2008 under the Endocrine Disrupter Demonstration Programme, are having wider effects on breeding success and stability of fish populations - in comparison with a clean reference river.

Substances of especial interest include oestrogens and their mimics (but also androgens, and their respective antagonists), which are already known to be causing feminisation or de-masculinisation of individual fish and reductions in their reproductive potential.

Oestradiol

Roach Rutilus rutilus

The secondary objectives of EDCAT are to develop models which can assist dischargers to predict which river systems would benefit most from remediation technology, and to reveal (Phase 2, 2008 onwards) the extent to which this new technology for the removal of oestrogens leads to ecosystem recovery in the River Ray. EDCAT will combine measurements and modelling of ED concentrations in the River Ray, with experimental measurements of breeding success in intersex roach Rutilus rutilus from the river, and measurements of physiological and population responses of wild sticklebacks Gasterosteus aculeatus.

Above & below: 3-spined stickleback
Gasterosteus aculeatus