| In recent years, estrogens have been detected in various aquatic ecosystems worldwide. Research findings have led to mounting concern that exposure to trace estrogens (ng/L) may interfere with the reproductive success of wildlife. These endocrine disrupting estrogens constitute natural steroid hormones such as estrone (E1), 17beta-estradiol (E2), and estriol (E3) and their synthetic counterparts such as 17alpha-ethinylestradiol (EE2) and mestranol (MeEE2), which are major components of contraceptive pills. However, much work still remains toward thoroughly understanding these estrogens in the environment. We started our investigations evaluating the environmental hazard posed by estrogens with respect to their occurrence, biodegradation, and photochemistry in a selected aquatic environment.; A GC-MS analytical procedure for the simultaneous determination of both natural and synthetic estrogenic steroids (E1 and EE2) in water was developed and validated. Using N, O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) + trimethylchlorosilane (TMCS) + pyridine as derivatization reagent, a single and stable di-TMS derivative of EE2 was obtained at a temperature range 25-80°C with a derivatization time of 30 min. The developed method successfully solved incomplete derivatization of EE2 and decomposition of di-TMS derivative of EE2 that would invalidate the quantitative results of GC analysis.; Detection of three estrogens, E1, E2, and EE2, was achieved in Acushnet River Estuary seawater using the developed GC-MS method. The concentration of EE2 was up to 4.7 ng/L, at which EE2 may affect reproductive success of fish in the aquatic environment.; Degradation, including biodegradation and photodegradation, of E1, E2, E3, EE2, MeEE2 were examined in the river, lake, and seawater. Under aerobic conditions, biodegradation of the five estrogens was faster than under anaerobic conditions. In natural surface water, sunlight induced photochemical degradation of the five estrogens was much faster than their biodegradation.; Fe(III)-oxalato complexes catalyzed photolysis of E1, E2, E3, EE2, and MeEE2 was investigated under monochromatic UV light irradiation with emphases on the reaction kinetics, mechanism, and intermediate products. The Fe(III) catalyzed photolysis of E2, E3, EE2 or MeEE2 was significantly increased in the presence of 80 muM oxalate. (Abstract shortened by UMI.)... |
