1.Determination of natural and synthetic glucocorticoids in effluent of sewage treatment plants using ultrahigh performance liquid chromatography-tandem mass spectrometry
Tomohiko Isobe & Kentaro Sato & Kim Joon-Woo & Shinsuke Tanabe & Go Suzuki & Kei Nakayama. Environ Sci Pollut Res (2015) 22:14127–14135
Concentrations of the detected GCs during diurnal variation study (STP-EW) were summarized in Table 2 and Fig. 2. Among the 10 target GCs, only four groups of compounds including cortisol, dexamethasone+betamethasone, betamethasone valerate, and prednisolone were detected and the others were below MDLs. Because beclomethasone dipropionate is a pro-drug and difluprednate is an antedrug, these compounds could be metabolized immediately after administration and not found in waste-water. Cortisol, which was the most frequently detected compound, was found in all the analyzed effluent samples within the range of 0.42–1.36 ng/L. Although diurnal variation in concentration was not substantial, cortisol levels were slightly higher in the afternoon samples than those collected in morning and night. During sampling period, physical/chemical characteristics (water temperature, pH, and conductivity) of effluent were fairly constant (Table 2), suggesting that waste-water treatment efficiency could be stable over time and diurnal variation in cortisol level might result from variation in levels in influent. This trend might be affected by our usual lifestyle pattern, although we could not get supporting evidence. Since normal residential time of treatment plant is 8 h, high levels of cortisol observed in the afternoon could reflect the intensive use of shower and/or toilets in the morning. In contrast to cortisol, dexamethasone+betamethasone, betamethasone valerate and prednisolone were detected only in 5, 3, and 2 samples, respectively, among the 13 analyzed effluent samples.