Effects of 17α-ethinylestradiol on sex ratio, gonadal histology and perianal hyperpigmentation of Cnesterodon decemmaculatus (Pisces, Poeciliidae) during a full-lifecycle exposure

CRISTOS, DIEGO SEBASTIÁN; CARRIQUIRIBORDE, PEDRO; CRESPO, DIANA CRISTINA; YOUNG, BRIAN JONATHAN; SOMOZA, GUSTAVO MANUEL

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2020 vol. 205 p. 1 - 9

0147-6513

The effects of 17α-ethinylestradiol (EE2 ) on sex ratio, gonopodium morphology, and gonadal histology of C. decemmaculatus were assessed by full-lifecycle exposure experiment. Newborn fish were waterborne exposed to 30, 100, and 300 ng EE2 /L for 90 d, using 50 fish per treatment. Additionally, in December of 2016, a field survey was conducted on a C. decemmaculatus population inhabiting the Girado Creek downstream of the Chascomus city wastewater effluent discharge. After 90 d of exposure, EE2 was able to histologically skew the sex ratio toward females and inhibit the full gonopodium development since the lowest tested concentration (LOEC =30 ng/L). At higher concentrations, EE2 was toxic, inducing mortality in a concentration-dependent fashion (90 d-LC 50 = 109.9 ng/L) and altering the gonadal histoarchitecture, causing neither testis nor ovaries discernable histologically (LOEC =100 ng/L). In addition, a novel response, perianal hyperpigmentation, was discovered been induced by the EE 2 exposure in a concentration-dependent fashion (90 d-EC 50 = 39.3 ng/L). A higher proportion of females and perianal hyperpigmentation were observed in wild fish collected from the Girado Creek. The major reached conclusions are: i) EE 2 induce different effects on the sexual traits of C. decemmaculatus whenexposed from early-life or adult stages. ii) The most sensitive effects observed in the laboratory occur in a creek receiving wastewater effluent. iii) The perianal hyperpigmentation comes-up as a promising biomarker of exposure to estrogenic compounds.