title: Uptake, elimination, and biotransformation of 17α-ethinylestradiol by the freshwater alga Desmodesmus subspicatus.
abstract: Bioconcentration and transformation of the potent and persistent xeno-estrogen 17α-ethinylestradiol (EE2) by organisms at the basis of the food web have received only little research attention. In this study, uptake, elimination, and biotransformation of radiolabeled EE2 ((14)C-EE2) by the freshwater green alga Desmodesmus subspicatus were investigated. The alga highly incorporated radioactivity following (14)C-EE2 exposure. Up to 68% of the test compound was removed from the medium by D. subspicatus within a rather short time period (72 h C(algae)/C(water): 2200 L/kg wet weight). When the algae were transported to clear medium, a two-stage release pattern was observed with an initially quick elimination phase following slower clearance afterward. Interestingly, D. subspicatus brominated EE2 when bromide was available in the medium, a transformation process demonstrated to occur abiotically but not by algae. The consequence of the presence of more hydrophobic mono- and dibrominated EE2 in the environment remains to be further investigated, as these products were shown to have a lower estrogenic potency but are expected to have a higher bioaccumulation potential and to be more toxic than the mother compound.
authors.affiliation: Institute for Environmental Research (Biology V), RWTH Aachen University , Worringerweg 1, Aachen 52074, Germany.
authors.forename: Hanna Maja
authors.initials: HM
authors.lastname: Maes
authors.forename: Sibylle Xenia
authors.initials: SX
authors.lastname: Maletz
authors.forename: Hans Toni
authors.initials: HT
authors.lastname: Ratte
authors.forename: Juliane
authors.initials: J
authors.lastname: Hollender
authors.forename: Andreas
authors.initials: A
authors.lastname: Schaeffer
mesh_terms: D001711:Biotransformation; D000460:Chlorophyta / Q000378:metabolism*; D052244:Endocrine Disruptors / Q000378:metabolism*; D004967:Estrogens / Q000633:toxicity; D004997:Ethinyl Estradiol / Q000378:metabolism*; D005618:Fresh Water; D054879:Halogenation; D007700:Kinetics; D010839:Phytoplankton; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D052244:Endocrine Disruptors; D004967:Estrogens; D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol