17α-ethinyl estradiol induces behavioral and reproductive damages in zebrafish (Danio rerio)

Abstract

Synthetic estrogen 17α-ethinyl estradiol (EE2) is recognized for its ability to cause endocrine disruption in aquatic organisms and its high resistance to environmental degradation, being found in Brazilian waterbodies up to 100 ng L -1 . Thus, the aim of this study was to evaluate the exploratory behavior and the histological effects on zebrafish gonads, caused by environmentally relevant concentrations of EE2. Females were exposed to nominal concentrations of 25 ng L -1 and 100 ng L -1 EE2 for 21 days. After that, a behavioral and histological analysis of gonads was performed. The EE2 caused the reduction of the exploratory activity of the animals, when observed the behavior, and an acceleration of the maturation process of the oocytes evaluated in the histological analysis. Considering the results obtained after the exposure to EE2, we highlight the concern about the potential risks it may cause to the aquatic biota, alerting to the need to control and monitor these micropollutants present in Brazilian water resources.

Development of the integrated fish endocrine disruptor test (iFEDT)—Part A: Merging of existing fish test guidelines

“…Overall, EE2 exposure leads to a decrease or retardation of gonadal maturation (Baumann et al, 2014), which was evident in F 1 females after exposure to both 0.6 and 2.5 ng/L, as well as males exposed to 2.5 ng/L EE2. However, life stage, exposure duration, and exposure concentrations need to be considered since an acceleration of oocyte maturation linked to an increase of VTG levels has also been documented in adult zebrafish exposed to 100 ng/L EE2 for 21 days (Schuster et al, 2019). Moreover, EE2-induced effects on female gonad differentiation and maturation are, at least to some extent, reversible, whereas masculinizing effects are not (Baumann et al, 2014).…”