Article

First report of intersex roach residing in Irish rivers downstream of several wastewater treatment plants

Authors:
  • Technological University of the Shannon (formerly Athlone Institute of Technology)
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Abstract

Endocrine disrupting chemicals (EDCs) are chemicals that have the ability to mimic or disrupt the endocrine system in wildlife. Many of these EDCs are present in treated Irish sewage effluents and landfill leachate and have recently been identified in Irish rivers. The effects of exposure to EDCs were investigated in Irish brown trout (Salmo trutta), sampled from selected Irish rivers downstream of Irish wastewater treatment plants (WWTPs) with control fish sampled upstream of the same WWTP. The effects were also investigated in Irish roach (Rutilus rutilus) sampled downstream of Irish WWTPs. Control roach were sampled from a pristine salmon fishery river (River Deel) located in the west of Ireland. Histopathological and macroscopic analyses of downstream trout showed no adverse reproductive effects, compared to control fish sampled upstream of the WWTP. Statistically significant (p <0.05) populations of wild roach from three sampled Shannon basin rivers were, however, observed to be phenotypically intersex (ovo-testis) when compared to the control river. This, it is hypothesised, is as a direct result of exposure to WWTP effluents. The results reported herein are the first observations of intersex fish in Irish rivers.

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... been the case of some marine gastropod molluscs, whereby male characteristics (penis and vas deferens) were superimposed onto females in response to TBT exposure derived from antifouling paints which, in severe cases in some species resulted in sterility and population decline ( Barroso et al., 2000;Bauer et al., 1995Bauer et al., , 1997Bryan et al., 1993Bryan et al., , 1986bBryan et al., , 1987Gibbs et al., 1991aGibbs et al., , 1987Gibbs et al., , 1988Gibbs et al., , 1991bOehlmann et al., 1998). The opposite response, feminisation of male individuals, has been most widely reported in freshwater fish exposed to EDCs derived from sewage treatment works and other sources (Hinck et al., 2009;Jobling et al., 1998;McGee et al., 2012;Pollock et al., 2010;Sanchez et al., 2011;Tetreault et al., 2011;Vajda et al., 2011). However, the physical manifestation of intersex (feminization) may take several forms including production of the egg-yolk precursor protein vitellogenin ( Arukwe et al., 2000;Harries et al., 1997;Kime et al., 1999;Leonardi et al., 2010;Matozzo et al., 2008;Routledge et al., 1998); formation of female-like ducts ( Jobling et al., 2002;Liney et al., 2005;Nolan et al., 2001); and the occurrence of oocytes in testicular tissue (ovotestis) ( Bateman et al., 2004;Chesman and Langston, 2006;Langston et al., 2007;Liney et al., 2005;Matthiessen et al., 2002;Nadzialek et al., 2010;Stentiford and Feist, 2005;Stentiford et al., 2003). ...
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... Since the first report on intersex in fish (Goldschmidt, 1931) there has been a dramatic increase over the past eight decades in reports of intersex in fish. Many of the intersex incidences are correlated with different anthropogenic sources of pollutants, especially those chemicals that have an estrogenic mode of action (Dutney et al., 2017;Hinck et al., 2009;Jobling et al., 2002;McGee et al., 2012;Miller et al., 2012). There is only a limited evidence of anthropogenic impact in causing intersex in marine fishes. ...
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Alterations in development and reproduction as a consequence of exposure to endocrine-disrupting chemicals (EDCs) have been demonstrated in many wildlife species. Animals living in, or closely associated with, the aquatic environment are particularly vulnerable to endocrine disruption because thousands of chemicals are actively disposed into rivers, estuaries and seas. Fish have thus been a focus in endocrine disruption studies, and some of the most comprehensive studies on the disruption of sexual development and function are on the roach (Rutilus rutilus). This paper provides a critical analysis of the roach as a sentinel for studies into endocrine disruption. The paper starts by describing what is known on the basic reproductive biology of the roach, information essential for interpreting chemical effect measures on sexual development and function. We then analyze where and how the roach has been applied to improve our understanding of the estrogenic nature of discharges from wastewater treatment works (WWTWs) and describe the phenomenon of feminized male roach in UK rivers. In this paper, the causation of these effects and issues of relative susceptibility and sensitivity of the roach to the effects of estrogenic EDCs are addressed. The paper then describes the ongoing work on the development of genetic and genomic resources for roach and analyses how these are being applied in studies to understand the mechanisms of disruption of sexual development. Finally, the paper addresses the biological significance of sexual disruption and intersex for the individual and discusses the possible implications for wild populations.
Article
Ovotestis (intersex) and raised plasma vitellogenin in male fish are widely employed biomarkers of estrogen contamination in the aquatic environment. In the present study, these biomarkers were used to determine whether Irish rivers contain estrogenic chemicals at levels capable of affecting the reproductive health and success of exposed fish populations. A number of aquatic ecosystems were investigated (the rivers Liffey, Lee, and Bandon and the Killarney lakes). A survey of male wild brown trout (Salmo trutta) was carried out to assess the incidence of endocrine disruption in the feral fish population; no evidence of intersex was found in any of the wild fish sampled. Raised plasma vitellogenin was detected, however, in the wild brown trout downstream of a major municipal wastewater treatment plant on the river Liffey.