| Statistical Modeling Suggests that Antiandrogens in Effluents from Wastewater Treatment Works Contribute to Widespread Sexual Disruption in Fish Living in English Rivers Susan Jobling,1,2 Robert.W. Burn,3 Karen Thorpe,4 Richard Williams,5 and Charles Tyler4 1Institute for the Environment, Brunel University, Uxbridge, Middlesex, United Kingdom; 2Beyond the Basics Ltd., Burnham, Buckinghamshire, United Kingdom; 3Statistical Services Centre, School of Biological Sciences, University of Reading, Reading, United Kingdom; 4Ecotoxicology and Aquatic Biology Research Group, School of Biosciences, University of Exeter, Exeter, Devon, United Kingdom; 5CEH Wallingford (Centre for Ecology & Hydrology), Wallingford, Oxfordshire, United Kingdom Abstract
Background: The widespread occurrence of feminized male fish downstream of some wastewater treatment works has led to substantial interest from ecologists and public health professionals. This concern stems from the view that the effects observed have a parallel in humans, and that both phenomena are caused by exposure to mixtures of contaminants that interfere with reproductive development. The evidence for a “wildlife–human connection” is, however, weak: Testicular dysgenesis syndrome, seen in human males, is most easily reproduced in rodent models by exposure to mixtures of antiandrogenic chemicals. In contrast, the accepted explanation for feminization of wild male fish is that it results mainly from exposure to steroidal estrogens originating primarily from human excretion. Objectives: We sought to further explore the hypothesis that endocrine disruption in fish is multi-causal, resulting from exposure to mixtures of chemicals with both estrogenic and antiandrogenic properties. Methods: We used hierarchical generalized linear and generalized additive statistical modeling to explore the associations between modeled concentrations and activities of estrogenic and antiandrogenic chemicals in 30 U.K. rivers and feminized responses seen in wild fish living in these rivers. Results: In addition to the estrogenic substances, antiandrogenic activity was prevalent in almost all treated sewage effluents tested. Further, the results of the modeling demonstrated that feminizing effects in wild fish could be best modeled as a function of their predicted exposure to both antiandrogens and estrogens or to antiandrogens alone. Conclusion: The results provide a strong argument for a multicausal etiology of widespread feminization of wild fish in U.K. rivers involving contributions from both steroidal estrogens and xenoestrogens and from other (as yet unknown) contaminants with antiandrogenic properties. These results may add further credence to the hypothesis that endocrine-disrupting effects seen in wild fish and in humans are caused by similar combinations of endocrine-disrupting chemical cocktails. Key words: antiandrogen, endocrine disruption, estrogen, feminization, fish, testicular dysgenesis. Environ Health Perspect 117:797–802 (2009) . doi:10.1289/ehp.0800197 available via http://dx.doi.org/ [Online 7 January 2009]
Address correspondence to S. Jobling, Institute for The Environment, Brunel University, Uxbridge, Middlesex, UK UB83PH. Telephone: 44-793-206-6351. E-mail: susan.jobling@brunel.ac.uk Supplemental Material is available online at http://www.ehponline.org/members/2009/0800197/suppl.pdf Statistical modeling was supported by Beyond The Basics Ltd. and the U.K. Environment Agency. The U.K. National Survey of hormonal activity and chemical monitoring was sponsored by The U.K. Environment Agency. C.R.T. was further supported by the Natural Environment Research Council (NER/ NE/E016634/1) . S.J. is employed by Beyond the Basics Ltd., an independent consultancy. The other authors declare they have no competing financial interests. Received 17 September 2008 ; accepted 6 January 2009.
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