Dynamics of steroid estrogen daily concentrations in hospital effluent and connected waste water treatment plant.

Hospital effluent and connected waste water treatment plant (WWTP) influent and effluent were sampled daily to determine the levels and inter-day variations of three naturally occurring steroid estrogens: estrone, 17β-estradiol, estriol, and synthetic 17α-ethinylestradiol. After solid phase extraction, interferences were removed with a silica gel clean-up step and the samples analysed using gas chromatography with mass selective detection (GC-MSD). The determined inter-day concentrations in hospital effluent were between 8.6 to 31.3 ng L(-1) for estrone,