The impact of chromophoric dissolved organic matter on the photodegradation of 17α-ethinylestradiol (EE2) in natural waters

17 alpha-Ethinylestradiol (EE2), the potent estrogen which forms the basic constituent of the contraceptive pill, can undergo degradation in natural waters by sunlight and via secondary reactions initiated by photo-excited dissolved organic matter. The current paper presents the findings of an investigation into the irradiation process of EE2 when dissolved in natural waters. This investigation was carried out under simulated sunlight in samples of sea, river and distilled water at a 17 alpha-ethinylestradiol concentration of 300 ng L-1. Several notes of significance may be made on the basis of these results. Firstly, an enhancement of the degradation, observed in the presence of co-absorbing dissolved organic matter, was shown to be proportional to the absorbance of the sample. Secondly, the kinetics of the process obtained during this investigation were within the range of previously reported findings, despite the fact that significantly higher concentrations of EE2 were used in earlier studies. Finally, the environmental half-life times for 17 alpha-ethynyloestradiol, calculated from the results of the experiments, were found to be one and two days in the top layer of river and sea water respectively. (C) 2014 Elsevier Ltd. All rights reserved.