Effects of the mixture of two endocrine disruptors (ethinylestradiol and levonorgestrel) on selected ecological endpoints ofAnuraeopsis fissaandBrachionus calyciflorus(Rotifera)

Abstract

In Mexico ethinylestradiol (ETE) and levonorgestrel (LEV) are regularly produced and utilized for birth control by women. In this work, we tested the effect of both hormones on the life table demography (LTD) of the rotifersAnuraeopsis fissaandBrachionus calyciflorus, exposed to different concentrations of mixed LEV and ETE in a ratio of 5:1 (500/100, 250/50, 125/25, 62.5/12.5, 31.25/6.25 for the rotifers but with an additional level of 15.625/3.125 µg L−1forB. calyciflorus). We also tested the effect of these endocrine disruptors on the population growth rate ofA. fissa. Our results showed that significant differences with respect to the control in the lower concentrations of the hormones corresponding to 31.25/6.25 and 62.5/12.5 µg L−1of LEV/ETE. Among the life history variables ofA. fissa, the average lifespan and net reproductive rate were stimulated by the mixed hormones at 31.25/6.25 of LEV/ETE. Both gross and net reproductive rates and the rate of population increase per day ofB. calycifloruswere stimulated by the higher levels (250/50 and 500/100 µg L−1) of endocrine disruptors.