EDCAT aims to investigate whether complex mixtures of endocrine disrupting chemicals in fresh waters, known to affect individual fish, are causing ecologically relevant effects at the catchment scale. The project is of direct relevance to CGMP policy development, since it will help to provide a scientific basis for demonstrating potential environmental impacts of endocrine disrupting chemicals, as required under REACH.
EDCAT comprises 5 separate projects and will `piggy-back` on the forthcoming Demonstration Programme planned by the Water Industry, the Environment Agency and Defra Water Quality Division to investigate cost-effective methods for the removal of oestrogenic substances from sewage treatment effluents.
Phase 1 of EDCAT will establish a baseline in impacted receiving water up to 2008, when the new water treatment plant will be ready at the study sites. Phase 2 will study recovery of the system after the new plant begins to operate in 2008 and will form the basis of a separate programme in due course.
It is now well established that in many rivers in the UK quite a high proportion of the males of some species of fish are feminised to varying degrees, as a result of exposure to oestrogenic chemicals present in the water. This project, EDCAT 7, will determine whether or not feminised roach can reproduce, and if so, how successful they are when they spawn together with other fish in shoals. The project is divided into two contracts - 7B with Brunel University, and 7A with the University of Exeter(see CB01083).
Groups of roach (representative of a naturally spawning shoal) containing both normal and feminised fish, will be allowed to spawn naturally in large fish tanks. The eggs will be allowed to develop without interference and the offspring grown normally. Once the young are large enough, genetic fingerprinting techniques will be used to assign the offospring to the parents. In this way we will discover which adults contributed to the nsxt generation and to what degree. Thus we will find out when in groups containing normal (not feminised) fish, whether or not feminised fish can reproduce and if so, how successfully compared to normal fish. This information will enable us to deduce whether or not feminisation of male fish poses a threat to the long-term sustainability of fish populations.