Sorption of the natural endocrine disruptors, oestrone and 17 beta-oestradiol in the aquatic environment.

Adsorption of hydrophobic contaminants at the particle/water interface is one of the key processes controlling their fate in the aquatic environment. The sorption of the natural female hormones oestrone and 17 beta-oestradiol has been studied under simulated riverine conditions. Both the kinetics and the effects of varying fundamental environmental parameters (e.g. sediment properties) on the thermodynamic equilibrium partition coefficient (Kp) have been studied in continuous and batch sorption experiments, respectively. Results showed that the sorption of oestrone and 17 beta-oestradiol by sediment was relatively slow, reaching equilibrium in 50 days. In addition, relatively small adsorption of both oestrone and 17 beta-oestradiol onto the sediment was observed, with Kp values between 200 and 250 mL g-1. The comparable Kp values of the two compounds reflect their structural similarity. It can be concluded that the two endocrine disruptors, oestrone and 17 beta-oestradiol remain primarily in association with the aqueous phase.