Environmental factors affecting ultraviolet photodegradation rates and estrogenicity of estrone and ethinylestradiol in natural waters.

The environmental fate and persistence of steroidal estrogens is influenced by their photodegradation. This can potentially occur both in the presence of the ultraviolet (UV) portion of solar radiation and in tertiary wastewater treatment plants that use UV radiation for disinfection purposes. To determine patterns of UV photodegradation for estrone (E1) and 17α-ethinylestradiol (EE2), water samples containing these compounds were exposed to levels of UVB radiation that would simulate exposure to ambient sunlight. E1 degraded with a pseudo-first-order rate law constant that was directly proportional to UVB radiation intensity (R² = 0.999, P < 0.001) and inversely proportional to dissolved organic carbon (DOC) concentration (R² = 0.812, P = 0.037). DOC acted as a competitive inhibitor to direct photolysis of E1 by UV. In contrast to E1, EE2 was more persistent under similar UVB treatment. A reporter gene assay showed that the estrogenicity of UVB-exposed estrogens did not decrease relative to non-UVB-exposed estrogens, suggesting that some of the photoproducts may also have estrogenic potency. These results show that environmental degradation rates of steroidal estrogens are predictable from the UV intensity reaching surface waters, and the DOC concentrations in these surface waters.

Degradation of estrone in aqueous solution by photo-Fenton system.

Photodegradation of estrone (E1) in aqueous solutions by UV-VIS/Fe(III)/H2O2 system (photo-Fenton system) was preliminarily investigated under a 250-W metal halide lamp (lambda > or = 313 nm). The influences such as initial pH value, initial concentration of Fe(III), H2O2 and E1 on degradation efficiency of E1 were discussed in detail. The results indicated that E1 could be decomposed efficiently in UV-VIS/Fe(III)/H2O2 system. After 160-min irradiation, the photodegradation efficiency of 18.5 micromol L(-1) E1 reached 98.4% in the solution containing 20.8 micromol L(-1) Fe(III), and 1664 micromol L(-1) H2O2 at initial pH value 3.0. The degradation efficiencies of E1 were dependent on initial pH value, Fe (III) concentration and H2O2 concentration. The degradation of four estrogens estrone (E1), estradiol (E2), 17alpha-ethynylestradiol (EE2) and diethylstibestrol (DES) in UV-VIS/Fe(III)/H2O2 system were also conducted. Under the conditions of pH 3.0, the E1 apparent kinetics equation -dC(E1)/dt=0.00093[H2O2]0.47[Fe(III)]0.63[E1]0.24 (r=0.9935, n=11) was obtained. The E1 mineralization efficiency was lower than degradation efficiency under the same conditions, which implied the mineralization occurred probably only at aromatic ring. There are several intermediate products produced during the course of E1 degradation. The comparison of the degradation efficiencies of E1, E2, EE2 and DES degradation in UV-VIS/Fe(III)/H2O2 system were also conducted, and the relative degradability among different estrogens were followed the sequence: DES>E2>EE2>E1.

Simultaneous Degradation of Estrone, 17ß-Estradiol and 17α-Ethinyl Estradiol in an Aqueous UV/H2O2 System.

UV/H2O2, which is an advanced treatment technology used to reduce multiple contaminants, is effective in potable water treatment. Simultaneous degradation effects and kinetics of three types of coexisting micropollutant estrogens (steroid estrogens, SEs), including estrone (E1), 17ß-estradiol (E2) and 17α-ethinyl estradiol (EE2), in deionized water were studied. Experiments were carried out with ultraviolet-C (UVC) radiation, together with hydrogen peroxide (H2O2), in a cylinder photoreactor. The results demonstrated that the degradation processes of all of the estrogens strongly fit first-order kinetics. Single solutions of E1, E2 and EE2 showed higher degradation rates and removal efficiencies under the same reaction conditions compared with those under mixed conditions. Coexisting combinations of estrogens were put into the UV/H2O2 system to estimate their possible competitive influences on each other by examining their removal efficiencies and reaction rate constant, k, values. E1 is predominantly reduced rapidly during the competition, while the presence of other estrogens has negligible impacts on E1; however, the degradation of E2 and EE2 is affected by the competitive background, not in relation to the types but to the existing amounts. In the UV/H2O2 system, photocatalysis of the estrogens can stably produce an intermediate X, with the highest quantity coming from E1, while considerably lower quantities are obtained from E2 and EE2.

Lumi-mestranol and epi-lumi-mestranol.

Treatment of lumi-estrone 3-methyl ether (I) with acetylene gave the C-17-epimeric compounds lumi-mestranol (3-methoxy-17 alpha-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 beta-ol, III ) and epi-lumi-mestranol (3-methoxy-17 beta-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 alpha-ol, IV). The structures of the two isomers were assigned on the basis of their molecular rotations and shift-reagent experiments in the NMR. The irradiation of estrone 3-methyl ether (II) to provide compound I was investigated in two solvent systems. Minor products of these reactions were the seco-steroids VII, VIII and X.

Interaction of the photosensitization products of oestrone with DNA: comparison with the horseradish peroxidase catalyzed reaction.

The interaction with DNA of [4-14C]oestrone upon photosensitization with hematoporphyrin (HP) as a photosensitizer has been investigated. By means of Sephadex LH-20 gel filtration and extraction with dichloromethane it was found that, after irradiation (lambda greater than 425 nm) of a solution of HP, DNA and [4-14C]oestrone 21% of the radiolabel was associated with DNA. If DNA was added after irradiation 23% was bound to DNA, whereas 25% of the oestrone remained after photoreaction under the conditions applied. The binding occurs via the reactive 10 beta-hydroperoxy-1,4-estradien-3,17-dione, which is the only product after photosensitization of oestrone. The hydroperoxide has a strong interaction with DNA compared with that of other steroids. By repeated precipitation with 5 M NaCl and ethanol the association can be broken. It is reported, that binding of oestrone to protein induced by both photosensitization and horseradish peroxidase (HRPO)/H2O2 is irreversible, but that the amount of binding to DNA is dependent on the method of determination. However, neither the hydroperoxide nor its reduced product, a p-quinol, is intermediate or product in the HRPO catalyzed reaction of oestrogens. The tight association of the hydroperoxide product of oestrone with DNA, which may proceed via hydrogen bonding between the -OOH group and oxygen atoms of the backbone phosphate groups or of the furanose ring, might be a cause of chemical modification of DNA and of mutagenic effects.

Photolysis of estrone generates estrogenic photoproducts with higher activity than the parent compound.

In the present study, we aimed to evaluate the effect of UV-visible irradiation on the estrogenicity of an estrone aqueous solution by using chemical analysis associated with an in vitro bioassay and in silico analysis. An estrone aqueous solution was irradiated with an UV-visible high-pressure mercury lamp. By using the MELN in vitro cellular bioassay, based on the induction of a luciferase reporter gene upon the activation of the estrogen receptor by chemicals, we showed that the estrogenic potency of the solution increased after irradiation. High-performance liquid chromatography fractionation of the photolyzed solution followed by in vitro testing of fractions allowed the quantitation of the estrogenic potency of each fraction. Nine photoproducts were detected and characterized by liquid chromatography-mass spectrometry coupling. The observed estrogenic activity is mediated by mono- and multi-hydroxylated photoproducts; it is influenced by the position of hydroxyl groups on the steroidal skeleton. In addition, a structure-activity analysis of the hydroxylated photoproducts confirmed their ability to act as estrogen receptor ligands.

Photodegradation of estrone enhanced by dissolved organic matter under simulated sunlight.

In the present work the degradation of estrone (E1) a natural estrogenic hormone has been studied under simulated solar irradiation. The photodegradation of E1 has been investigated in the absence and in the presence of 7.7-8.9 mg L(-1) of dissolved organic carbon (DOC), under solar light simulation with irradiance approximating that of the sun. DOC extracts from different origins have been used. Half-lives ranging between 3.9 h and 7.9 h were observed. Results indicated that E1 was photodegraded even in the absence of DOC. The presence of DOC was found to enhance the degradation of E1. Experiments performed with the addition of reactive species scavengers (azide ions and 2-propanol) have shown that these two species play a significant role in the photodegradation. Some experiments have been performed with a DOC previously submitted to solar irradiation. Changes in optical and physico-chemical properties of DOC strongly affect its photoinductive properties, and hence its efficiency on E1 degradation. A part of the study consisted in the investigation of photoproducts structures. Five photoproducts were shown by chromatographic analysis: one arising from direct photolysis and the four others from DOC photoinduced degradation.

Photosensitized irreversible binding of estrone to protein via a hydroperoxide intermediate: an explanation of (photo-) allergic side-effects of estrogens.

After irradiation (lambda greater than 425 nm) for 15 min of a solution of [4-14C]-estrone, albumin and the photosensitizer hematoporphyrin in phosphate buffer, more than 30% of the radioactivity could not be extracted. When the protein was added after irradiation, irreversible binding also occurred. Sephadex gel filtration showed that the radiolabel was bound to albumin as well as to the photosensitizer. A 10 beta-hydroperoxide is the reactive intermediate in this binding. Inasmuch as phenolic steroids coupled to proteins have been used for the induction of estrogenic-specific antibodies, the irreversible binding observed between estrone and albumin by photosensitization might be an explanation for (photo)allergic disorders associated with estrogens.