LC-MS measurment of free steroids in mussels (Mytilus trossulus) from the southern Baltic Sea.

The aim of this study was to identify and quantify natural steroid hormones (17β-estradiol E2, estriol E3, estrone E1, testosterone T) and xenoestrogen (17α-ethinylestradiol EE2) in gills and gonads of Mytilus trossulus from the Gulf of Gdańsk, Poland, using the LC-MS technique based on the enzymatic digestion of tissues, SPE extraction, and subsequent LC-MS analysis of the eluates. As a result, spatial differences in several steroid hormone concentrations were detected. While the highest concentrations of testosterone and natural estrogens were documented in mussels collected at the reference station (app. 13 ng g(-1) wet weight for T, 9 ng g(-1)w.w. for E2 and 3.5 ng g(-1)w.w. for E1), decreased levels of natural steroids and increased levels of 17α-ethinylestradiol (EE2) were determined in individuals from the sewage treatment plant zone (app. 5 ng g(-1)w.w. for T, 3 ng g(-1)w.w. for E1, 1 ng g(-1)w.w. for E2 and E3, 1 ng g(-1)w.w. for EE2). No statistically significant tissue-related changes in steroids concentrations were found, but a trend towards higher steroids level in gills than in gonad was observed.