EFFECTS OF THE SYNTHETIC ESTROGEN 17α-Ethinylestradiol ON THE LIFE-CYCLE OF THE FATHEAD MINNOW (PIMEPHALES PROMELAS)

Abstract

A fish full life-cycle (FFLC) study was conducted for 17 alpha-ethinylestradiol (EE2) using the fathead minnow, Pimephales promelas. Newly fertilized embryos (< 24 h old) were exposed to five concentrations of EE2 (0.2, 1.0, 4.0, 16, and 64 ng/L nominal) in continuous flow-through conditions for 305 d at 25 +/- 1 degrees C. Exposure concentrations were verified by 14C-EE2 radiochemistry, supported by radioimmunoassay, and mean measured values were > or = 70% of nominal. For the F0 adult phase until 301 d posthatch, the no-observed-effect concentrations (NOECs) for growth, survival, and reproduction (as egg production) were all > or = 1.0 ng/L. The NOEC values for F1 embryo hatching success and larval survival (at 28 d posthatch) were both > or = 1.0 ng/L. While statistically detectable changes in F1 growth were evident at 0.2 ng/L, these were not considered to be biologically significant when compared with historical control data. Male fish exposed to EE2 at 4.0 ng/L failed to develop normal secondary sexual characteristics; on the other hand, assumed females exposed to this level of EE2 were able to breed when paired with males that had not been exposed to EE2. Histology of F0 control, 0.2-, and 1-ng/L exposed fish at 56 d posthatch indicated an approximate female-to-male (F:M) sex ratio of 50:50 (with no ovatestes observed in the control), while fish exposed to EE2 at 4.0 ng/L for 56 d posthatch had a F:M sex ratio of 84:5 (with ovatestes in 11% of fish). After 172 d posthatch, no testicular tissue was observed in any fish exposed to EE2 at 4.0 ng/L. At the same time point, plasma vitellogenin levels were significantly higher in fish exposed to EE2 at 16 ng/L. A lack of sexual differentiation occurred in males at concentrations > or = 4.0 ng/L. Taking into account these data, the overall no-observed-adverse-effect concentration was considered to be 1.0 ng/L.

Effects of 17?-ethinylestradiol on zoo- and phytoplankton in lentic microcosms

“…However, the number of investigated species is low and test endpoints might not always be sensitive. A variety of authors have reported endocrine-disruptive effects on different animals in ng L -1 concentration ranges [9,10,11]. Unfortunately, no toxicity data for copepods, which seem to be most sensitive in this study, are available.…”

“…In fish first toxic effects were reported between 1 and 100 ng L -1 [8,9,10]. For invertebrates, Vandenberg et al showed effects on the sexual development of the amphipod Hyalella azteca in the concentration range 100 to 3420 ng L -1 [11].…”

Vorkommen natürlicher und synthetischer östrogener Steroide in Wässern des süd- und mitteldeutschen Raumes

“…EE2 induzierte Vitellogenin in juvenilen Karpfen bei 10 ng/L und in männlichen Regenbogenforellen bereits bei einer Konzentration von 0.1 ng/L [1,6]. In einer Langzeitstudie mit dem Fisch Pimephales promelas wurden Entwicklungsstö-rungen bei Konzentrationen von 4 ng/L beobachtet [7]. Diese Befunde deuten darauf hin, dass EE2 schon in sehr niedrigen Konzentrationen in Fischen Wirkungen hervorruft, die durch eine Störung des endokrinen Systems ausgelöst werden.…”

“…Diese Konzentrationen sind deutlich niedriger als populationsrelevante Effektkonzentrationen für die primären Zielorganismen Fische. Länge et al[7] berichten eine "No-observable-effect"-Konzentration (NOEC) für EE2 von 1 ng/L für die Spezies Pimephales promelas in einer 2-Generationen-Studie, bei der Entwicklung, Wachstum, Reproduktionserfolg sowie histopathologische Veränderungen an den Gonaden und Vitellogeninsynthese untersucht worden waren. Scholz und Gutzeit[30] ermittelten eine NOEC für EE2 von 1 ng/L für Oryzias latipes bezüglich Reproduktion und gonadosomatischem Index, nachdem die Fische über 2 Monate nach Eiablage exponiert worden waren.…”

Environmental Risk Assessment of Pharmaceuticals

“…Synthetic estrogens such as ethinyl estradiol can feminize fish, reduce fertilization rates, and obliterate populations at concentrations from 1 to 6 ηg/L (Länge et al 2001, Parrott and Blunt 2005, Kidd et al 2007. Synthetic steroids used for growth promotion in cattle can masculinize fish (Ankley et al 2001(Ankley et al , 2003.…”