title: Predicted exposures to steroid estrogens in U.K. rivers correlate with widespread sexual disruption in wild fish populations.
abstract: Steroidal estrogens, originating principally from human excretion, are likely to play a major role in causing widespread endocrine disruption in wild populations of the roach (Rutilus rutilus), a common cyprinid fish, in rivers contaminated by treated sewage effluents. Given the extent of this problem, risk assessment models are needed to predict the location and severity of endocrine disruption in river catchments and to identify areas where regulation of sewage discharges to remove these contaminants is necessary. In this study we attempted to correlate the extent of endocrine disruption in roach in British rivers, with their predicted exposure to steroid estrogens derived from the human population. The predictions of steroid estrogen exposure at each river site were determined by combining the modeled concentrations of the individual steroid estrogens [17beta-estradiol (E2), estrone (E1), and 17alpha-ethinylestradiol (EE2)] in each sewage effluent with their predicted dilution in the immediate receiving water. This model was applied to 45 sites on 39 rivers throughout the United Kingdom. Each site studied was then categorized as either high, medium, or low "risk" on the basis of the assumed additive potency of the three steroid estrogens calculated from data derived from published studies in various cyprinid fish species. We sampled 1,438 wild roach from the predicted high-, medium-, and low-risk river sites and examined them for evidence and severity of endocrine disruption. Both the incidence and the severity of intersex in wild roach were significantly correlated with the predicted concentrations of the natural estrogens (E1 and E2) and the synthetic contraceptive pill estrogen (EE2) present. Predicted steroid estrogen exposure was, however, less well correlated with the plasma vitellogenin concentration measured in the same fish. Moreover, we found no correlation between any of the end points measured in the roach and the proportion of industrial effluents entering the rivers we studied. Overall, our results provide further and substantive evidence to support the hypothesis that steroidal estrogens play a major role in causing intersex in wild freshwater fish in rivers in the United Kingdom and clearly show that the location and severity of these endocrine-disrupting effects can be predicted.
authors.affiliation: Beyond The Basics Ltd, Burnham, Bucks, United Kingdom. drsusan-jobling@beyondthebasic.co.uk
authors.forename: Susan
authors.initials: S
authors.lastname: Jobling
authors.forename: Richard
authors.initials: R
authors.lastname: Williams
authors.forename: Andrew
authors.initials: A
authors.lastname: Johnson
authors.forename: Ayesha
authors.initials: A
authors.lastname: Taylor
authors.forename: Melanie
authors.initials: M
authors.lastname: Gross-Sorokin
authors.forename: Monique
authors.initials: M
authors.lastname: Nolan
authors.forename: Charles R
authors.initials: CR
authors.lastname: Tyler
authors.forename: Ronny
authors.initials: R
authors.lastname: van Aerle
authors.forename: Eduarda
authors.initials: E
authors.lastname: Santos
authors.forename: Geoff
authors.initials: G
authors.lastname: Brighty
mesh_terms: D000818:Animals; D015331:Cohort Studies; D003530:Cyprinidae / Q000002:abnormalities; D012734:Disorders of Sex Development / Q000139:chemically induced / Q000453:epidemiology; D052244:Endocrine Disruptors / Q000633:toxicity*; D004781:Environmental Exposure / Q000009:adverse effects*; D004967:Estrogens / Q000633:toxicity*; D005260:Female; D005262:Feminization / Q000139:chemically induced; D005399:Fishes; D005544:Forecasting; D008297:Male; D008962:Models, Theoretical; D009865:Oocytes / Q000187:drug effects; D018570:Risk Assessment / Q000379:methods; D045483:Rivers / Q000737:chemistry; D012722:Sewage / Q000737:chemistry; D046468:Sexual Development / Q000187:drug effects*; D013223:Statistics as Topic; D006113:United Kingdom; D014819:Vitellogenins / Q000097:blood / Q000378:metabolism
chemical_list: D052244:Endocrine Disruptors; D004967:Estrogens; D012722:Sewage; D014819:Vitellogenins