PARENT SESSION
PT2 - Endocrine Disruption
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P537) Identification and Biological Screening of Endocrine Disruptors in Effluents from Missouri Sewage Treatment Plants.

Huang, Yue-wern^*,1,2, Nam, Paul², ¹ Department of Biological Sciences, University of Missouri - Rolla, Rolla, MO, USA² Center for Environmental Science and Technology, University of Missouri - Rolla, Rolla, MO, USA

ABSTRACT- Effluent samples were taken from four Missouri municipal sewage treatment plants. Each effluent sample was subject to the solid phase extraction and then analyzed for natural estrogens, synthetic estrogens, pesticides, herbicides, and industrial chemicals using GC/MS. An aliquot of each water extract was reconstituted in DMSO, then further diluted in medium to test its ability to induce cell proliferation in MCF7 cells. The proliferation tests for each effluent are underway and the data will be compared with the standard curve of 17-estradiol (E2). Single chemicals that have been reported to be estrogenic and/or commonly present were also tested for their relative estrogenicities in induction of cell proliferation. In general, industrial chemicals such as 4-octylphenol, nonylphenols, 4-tert-octylphenol, dibutyl phthalate, butyl benzyl phthalate, and bisphenol A are more prevalent in the effluents compared with the other four types of chemicals. For the cell proliferation test, relative proliferative effect (RPE) was defined as the average maximal induction fold of each chemical normalized with that of E2, whereas the relative proliferative potencies (RPP) was defined as the EC50 of each chemical normalized with that of E2. The ranking order of the RPE of the five estrogens tested was E2 > 17-ethinylestradiol >> diethylstilbestrol > estriol > estrone. The average maximal fold inductions of these five chemicals were around 5-fold, with an exception of estrone at 3.68-fold. The RPP of 17-ethinylestradiol, diethylstilbestrol, and estriol were around 1.0; that is, their RPPs were comparable with that of E2. On the other hand, the RPP of estrone was 26% lower than the other four chemicals. The other three categories of the chemicals are either weak estrogens or non-estrogenic.

Key words: Sewage treatment plants, Endocrine disruptors, MCF7 cell proliferation, Chemical analysis