Baseline data from the EDCAT research programme on oestrogens and fish populations

The EDCAT programme now has over two year’s baseline data on the chemistry and fish biology of an English river, the Ray, which receives oestrogenic sewage effluent from the city of Swindon. It has developed models which predict oestrogen concentrations in the river throughout the year, and has successfully corroborated these with data on oestrogenic substances, in vitro oestrogenic activity, and non-oestrogenic contaminants. It has also gathered data on the dynamics and oestrogenic responses of stickleback populations in the river during a period when the sewage discharge received both normal dilution, and high dilution from unusually large river flows. Finally, breeding experiments with wild intersex roach have been conducted in which the breeding success of each individual has been tracked by microsatellite analysis of offspring. The Swindon (Rodbourne) sewage treatment plant has now been upgraded with granular activated carbon filtration technology to remove oestrogens, and future work of the EDCAT programme will monitor the rate of recovery of fish populations in the River Ray.