Absorption, Translocation and Metabolism of Bisphenol A, a Possible Endocrine Disruptor, in Rice Seedlings

Abstract

Rice seedlings quickly absorbed bisphenol A (BPA), a possible endocrine disruptor, in culture medium, indicating that they are capable of improving water quality. Measurements of BPA extracted from roots with the stem base and leaves/stems indicated that BPA was translocated from the roots to the top of the plants. The recovery rate by MeOH extraction was very low even during the absorption period, indicating that BPA is not bioaccumulated in the seedlings. The roots and tops of the rice seedlings cultured in the medium containing deuterium-labeled BPA, [2H] BPA, were extracted with MeOH and hydrolyzed with HC1 and NaOH. The extracts and the hydrolyzates were analyzed by 2HNMR. The spectral data indicated that about 5% of the metabolites, as [2H] BPA equivalents, was found in the MeOH extracts and ca. 25% in the acidic and alkaline hydrolyzates. The rest (ca. 70%) could be polymerized and/or bound in the tissues as insoluble, unhydrolyzable forms. The signals in the 2H-NMR spectra of the extracts and the hydrolyzates indicated that BPA was metabolized by oxidation and skeletal rearrangement to several compounds.