Vitellogenin concentrations in feral Danish brown trout have decreased: An effect of improved sewage treatment in rural areas?

Abstract

Feminization of male and juvenile fish because of exposure to estrogens or estrogenic chemicals in effluents from central wastewater treatment plants (WWTPs) is a worldwide issue of concern. Intersex and induction of the female yolk protein, vitellogenin, in male and juvenile fish are robust biomarkers for estrogenic exposure, and feminized fish have been observed downstream of WWTP outlets in many countries. Danish central WWTPs reduce effluent estrogenicity effectively by advanced sewage treatment, and feminizations have not been observed downstream of central WWTP outlets. However, between 2000 and 2004, investigations of Danish streams not receiving sewage from central WWTPs revealed a high variation in vitellogenin concentrations of male juvenile brown trout (Salmo trutta); some individuals had high concentrations, probably as a result of estrogenic point sources, and the plasma concentration was >50 ng mL in 79% of the juvenile males. The streams were reinvestigated in 2010 to 2016, and the average male level had decreased to a hitherto unseen baseline level; in 2010 only 0.7% (one individual) of the males had a vitellogenin concentration >50 ng mL , which could indicate that the estrogenicity of the streams decreased after 2004. We examined possible estrogenic sources in streams unaffected by central WWTP effluents, and found that the reduced vitellogenin levels are most likely explained by a national effort to improve on-site wastewater treatment in scattered houses not connected to central WWTPs. Environ Toxicol Chem 2018;37:839-845. © 2017 SETAC.

Monitoring of emerging contaminants of concern in the aquatic environment: a review of studies showing the application of effect-based measures

“…By quantifying estrogenicity of WWTP samples before and aer the treatment, it was possible to evaluate the water quality status aer treatment which translated to the effectiveness of the novel eco-friendly method and the WWTP respectively in wastewater treatment. In the same way, Giebner et al 78 quantied VTG levels in juvenile brown trout over two periods, between 2000 through 2004 and 2010 through 2016 to determine trend of chemical pollution in the river body. It was found that average VTG levels in the shes between 2000 and 2004 was signicantly higher than the quantied level between 2010 and 2016.…”

“…VTG secretion, unique to female sh species, has been widely used in different studies as a marker of feminisation in different male sh species due to estrogenic inuence of contaminants in water bodies. 78,85,[125][126][127][128][129][130][131][132][133] Assessment of VTG expression is oen used in conjunction with other estrogenicity bioassays as a complementary method for assessment of endocrine disruption within aquatic fauna. Such application was employed by Geraudie et al (2017) and Ganser et al (2019) in their studies where YES assay was used to evaluate estogenicity of water samples in addition to the VTG assay.…”

Endocrine Disruption Is Reduced but Still Widespread in Wild Roach (Rutilus rutilus) Living in English Rivers

“…It is difficult to reconcile these observations, but we cannot exclude other potential sources of upstream estrogenic contamination and our findings here are not unprecedented. For example, studies in rural Denmark suggested that environmental estrogens derive from domestic sewage treatment facility, such as septic tanks, after observing elevated plasma VTG in caged brown trout (Salmo trutta). , Furthermore, high-density livestock farming and the use of animal manures and sewage sludge on farmland can also be a diffuse source of estrogens entering surface waters (e.g., refs and ).…”

“…For example, studies in rural Denmark suggested that environmental estrogens derive from domestic sewage treatment facility, such as septic tanks, after observing elevated plasma VTG in caged brown trout (Salmo trutta). 40,49 Furthermore, high-density livestock farming and the use of animal manures and sewage sludge on farmland can also be a diffuse source of estrogens entering surface waters (e.g., refs 50 and 51). Our findings suggest that there has been a reduction in environmental estrogenic exposure between the mid-1990s and the contemporary assessment.…”