Thursday, November 5, 2009: 11:40 AM
Kohlberg (Camino Real Hotel)
Endocrine disruptor compounds (EDCs), such as estradiol (E2), estrone (E1) and alkylphenols, present analytical challenges in complex matrices at low levels (ng L-1). Even with a complete chemical characterization, it is not possible to anticipate net estrogenic effect due to simultaneous presence of many other trace organic residuals in treated water. Therefore, bioassays are necessary to measure net estrogenic activity in the whole water sample or corresponding concentrates. However, since bioassays respond to all substances with receptor-mediated estrogenic activity regardless of the chemical structure, chemical analysis is needed to identify the individual estrogenic compound in environmental samples. In this study the total estrogenic activity in wastewater was assessed using a chemiluminescents yeast estrogen screening (CYES) modified to test water samples directly. EDCs concentration was determined by Stir Bar Sorptive Extraction –Gas Chromatography-Mass Spectroscopy (SBSE-GCMS). The concentrations measured (CYES) in samples ranged from no activity (NA) to 28.4 of E2 equivalent (EEQ) ng L-1 . Calculated estrogenic activity (SBSE-GCMS) ranged from 2.1 to 155.9 EEQ ng L-1 . A regression analysis of measured and calculated EEQs showed that there is a positive correlation. This implies that at high concentration of EDCs in the water higher is the estrogenic activity. However, calculated EEQ values were approximately 3 times higher than CYES, probably due to the presence of potential interfering (antagonistic) compounds in water samples.