PARENT SESSION

2N - Field Studies
Poster Hall
8:30 AM - Monday, 28 April 2003
Chair: Liess, M.¹, ¹
Co-chair: Berghahn, R.², ²

(MOP/127) Effects of exposure to treated sewage effluent during early life on sexual development in roach (Rutilus rutilus).

Liney, Katherine¹, Jobling, Susan², Simpson, Peter³, Tyler, Charles¹, ¹ University of Exeter, Exeter, UK² Brunel University, Uxbridge, UK³ Environment Agency, Waterlooville, UK

ABSTRACT- Surveys of UK rivers have shown a high incidence of sexual disruption in roach (Rutilus rutilus) living downstream from some sewage treatment works (STW). It has been proven that STWs effluents are oestrogenic to fish, resulting in the induction of vitellogenin. Field data also strongly supports the contention that disruption in gonad development in fish is caused by exposure to STW effluents. A previous study showed that exposure of juvenile male roach from 50-150 days post-hatch (dph) to a single STWs effluent induced feminisation of the reproductive ducts but did not induce intersex (the simultaneous presence of both male and female germ cells in the gonad). In this study we exposed fertilised roach embryos/fry to two STWs effluents, (that included the effluent used in the previous studies) from fertilisation up to 300 days post hatch (dph; to cover the full period of gonadal sex differentiation in this species) to determine if effluent exposure during this period induces the intersex condition. Both effluents were oestrogenic to roach inducing vitellogenin. The magnitude of the vitellogenic responses paralleled the effluent content of steroid oestrogens. Both effluents also contained low mg/L concentrations of alkylphenols. Feminisation of the reproductive ducts occurred in all male fish in concentrations of effluent of 80% and higher, and depuration studies confirmed that this effect was permanent. There was, however, no evidence of major germ cell disruption in fish from either site. It still remains to be proven that STWs effluent induced germ cell disruption and if so what the critical life phase for this effect is.

Key words: roach, sexual disruption, sewage treatment works effluent