Institute for Environmental Research (Biology V), RWTH Aachen University , Worringerweg 1, Aachen 52074, Germany.
Environ Sci Technol. 2014 Oct 21;48(20):12354-61. doi: 10.1021/es503574z. Epub 2014 Oct 13.
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.
在食物网基础上的生物体对强持久性的外源性雌激素 17α-乙炔基雌二醇（EE2）的富集和转化受到的关注较少。本研究调查了淡水绿藻杜氏藻（Desmodesmus subspicatus）对放射性标记 EE2（（14）C-EE2）的吸收、消除和生物转化。藻类在（14）C-EE2 暴露后大量吸收放射性。在相当短的时间内（72 h 藻类中的 C（浓度）/水相中 C（浓度）：2200 L/kg 湿重），D. subspicatus 将测试化合物的 68%从培养基中去除。当藻类被转移到不含 EE2 的培养基中时，观察到一个两阶段的释放模式，最初是快速消除阶段，随后是较慢的清除阶段。有趣的是，当培养基中有溴化物时，D. subspicatus 会对 EE2 进行溴化，该转化过程被证明是由非生物因素而不是藻类引起的。环境中存在疏水性的单溴化和二溴化 EE2 的后果仍有待进一步研究，因为这些产物的雌激素活性较低，但预计具有更高的生物累积潜力和比母体化合物更高的毒性。
