Abstract
Endocrine disruptors such as bisphenol A (BPA) and nonylphenol have been frequently detected in environmental water. The objectives of this study were to evaluate the effects of chlorination on the estrogenic activity of BPA and its chlorination by-products. To quantify the estrogenic activity, a yeast two-hybrid assay was conducted. For the measurements of the concentrations BPA and its chlorination by-products, high performance liquid chromatography/mass spectrometry (LC/MS) analysis was used. As a result of BPA chlorination, monochloro-, dichloro-, trichloro- and tetrachloro-BPAs were detected in addition to the original BPA. To evaluate the contribution of each chlorinated BPA to the total estrogenic activity, the detected chlorinated BPAs were fractionated and the estrogenic activity of each chlorinated BPA was examined. Monochloro-, dichloro- and trichloro-BPAs showed higher estrogenic activities than BPA itself, but these activities decreased and were finally eliminated with reaction time. From these results, it is concluded that BPA chlorination is effective in eliminating estrogenic activity although chlorinated BPAs, which have stronger estrogenic activities than BPA, are formed temporarily.
