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 [17β -estradiol (E2), estrone (E1), and 17α -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.

Treatment of micropollutants in municipal wastewater: Ozone or powdered activated carbon?

“…Similar VTG concentrations (67.3 ± 26.9 ng ml -1 ) were found by Stalter et al (2010b) in juvenile rainbow trout exposed to secondary effluent. VTG, an egg yolk precursor normally produced by mature female fish, can be used as a biomarker for exposure to exogenous estrogens for juvenile and male fish (Jobling et al, 2006;Thorpe et al, 2000). The increase of VTG content in juvenile fish in BIO effluent indicates the presence of environmentallyrelevant concentrations of estrogenic compounds.…”

Research trends on emerging environment pollutants – a review

“…These results do not change the fact that long-term exposure to even low concentrations of active endocrine compounds may adversely affect human health [41]. Increased presence of the hermaphrodite fish populations in the reservoirs fed with purified water flowing from sewage treatment plants was observed in the US, Asia and Europe [42][43][44]. Still, however, there is a need to prove a direct relation between the presence of estrogens in surface waters, and changes in the sexuality of fish populations found in rivers, lakes and streams.…”

A Toxicological Assessment of Endocrine Disrupting Chemicals Found in the BMW (Border, Midland and Western) Region of Ireland

“…Many of the chemicals shown to mimic the action of endogenous oestrogens are reaching freshwater environments and water supplies in Ireland [18,19,34], the United Kingdom [35,36], the Netherlands [37], Germany [38,39], the USA [40] and China [41]. Bioaccumulation of these compounds should be taken into account for appropriate risk assessment.…”