Relative Potencies and Combination Effects of Steroidal Estrogens in Fish

Abstract

The natural steroids estradiol-17beta (E2) and estrone (E1) and the synthetic steroid ethynylestradiol-17alpha (EE2) have frequently been measured in waters receiving domestic effluents. All of these steroids bind to the estrogen receptor(s) and have been shown to elicit a range of estrogenic responses in fish at environmentally relevant concentrations. At present, however, no relative potency estimates have been derived for either the individual steroidal estrogens or their mixtures in vivo. In this study the estrogenic activity of E2, E1, and EE2, and the combination effects of a mixture of E2 and EE2 (equi-potent fixed-ratio mixture), were assessed using vitellogenin induction in a 14-day in vivo juvenile rainbow trout screening assay. Median effective concentrations, relative to E2, for induction of vitellogenin were determined from the concentration-response curves and the relative estrogenic potencies of each of the test chemicals calculated. Median effective concentrations were between 19 and 26 ng L(-1) for E2, 60 ng L(-1) for E1, and between 0.95 and 1.8 ng L(-1) for EE2, implying that EE2 was approximately 11 to 27 times more potent than E2, while E2 was 2.3 to 3.2 times more potent than E1. The median effective concentration, relative to E2, for the binary mixture of E2 and EE2 was 15 ng L(-1) (comprising 14.4 ng L(-1) E2 and 0.6 ng L(-1) EE2). Using the model of concentration addition it was shown that this activity of the binary mixture could be predicted from the activity of the individual chemicals. The ability of each individual steroid to contribute to the overall effect of a mixture, even at individual no-effect concentrations, combined with the high estrogenic potency of the steroids, particularly the synthetic steroid EE2, emphasizes the need to consider the total estrogenic load of these chemicals in our waterways.

Steroid Hormone Runoff from Agricultural Test Plots Applied with Municipal Biosolids

“…1,46−50 The lowest observed effect level (LOEL) affecting vitellogenin production in juvenile female rainbow trout was found to be as low as 3.3 ng E1/L. 51 Furthermore, the possible impact of hormone exposure on terrestrial organisms has not been documented. However, Kinney et al 52 demonstrated the uptake of wastewater-derived compounds by earthworms and this suggests the potential for bioaccumulation of these compounds in the food web.…”

Acute and chronic effects of testosterone and 4-hydroxyandrostenedione to the crustacean Daphnia magna

“…Several steroid hormones have been detected in water and sediment samples (Lai et al, 2000;Thorpe et al, 2003). Agricultural and other anthropogenic activities are principal non-point sources for steroid hormones in water and sediment systems (Kolpin et al, 2002).…”

Monitoring of selected estrogenic compounds and estrogenic activity in surface water and sediment of the Yellow River in China using combined chemical and biological tools

“…One of the most reported biological effects is fish feminization found in various rivers (Angus et al, 2002;Harries et al, 1997;Jobling et al, 1998;Kristensen et al, 2007;Xie et al, 2010). The observed effects in fish include vitellogenin induction, abnormal development of gonads (Harries et al, 1997;Lye et al, 1997;Jobling et al, 2002) and secondary sexual characteristics (Batty and Lim, 1999;Xie et al, 2010), which have been linked to some estrogenic compounds in the effluents of sewage treatment plants (Harries et al, 1997;Jobling et al, 2002;Lye et al, 1997;Thorpe et al, 2003;Xie et al, 2010). These compounds include 4-t-octylphenol (4-t-OP), 4-nonylphenols (4-NP), bisphenol-A (BPA), estrone (E1), estradiol (E2) and triclosan (TCS), which have been demonstrated to have in vitro and/or in vivo estrogenic activities (Foran et al, 2000;Ishibahsi et al, 2004;Jobling and Sumpter, 1993;Jobling et al, 1995;Raut and Angus, 2010;Stasinakis et al, 2008).…”