Contraceptive pill residues in sewage effluent are estrogenic to fish

The estrogenicity of sewage effluent water to fish has been described in several countries. Natural oestrogens have been confirmed as major causing agents in several British rivers. In a recent study (Larsson et al., Aquatic Toxicology, 1999, 91–97) we identified estrogenic substances by GC/MS in effluent water from a Swedish sewage treatment works receiving mainly domestic wastewater. Substances found include the synthetic estrogen used in contraceptives 17α-ethinylestradiol (4.5 ng/l), the natural estrogens estrone (5.8 ng/l) and 17β-estradiol (1.1 ng/l) and the weaker non-steroidal estrogens 4-nonylphenol (840 ng/l) and bisphenol A (490 ng/l). Ethinylestradiol exceeded levels shown to be estrogenic to fish by 45 times. The estrogenicity of the effluent water was investigated by introducing juvenile rainbow trout (Oncorhynchus mykiss) in cages downstream of the sewage treatment works. All estrogens indicated above were present in the bile of the fish, and the estrogen-inducible protein, vitellogenin, was found in large amounts in the plasma as determined by ELISA and Western blotting. At present we are studying effects further downstream on caged as well as wildcaught fish. Our studies suggest that a widely used synthetic estrogen affects the endocrine systems of fish exposed to sewage effluent water.