Abstract
Biodegradability of bisphenol (BPA) in aquatic environments was evaluated by a river die-away method using a variety of river water microcosms. Among 44 microcosms examined, 40 microcosms (ca. 90% of the total) exhibited BPA-degrading capability to a certain degree in an artificial river water. It suggested ubiquitous presence of BPA-degraders. However, among them only 6 samples showed complete degradation or mineralization of BPA shown as complete removal of TOC, and the other 34 microcosms accumulated common metabolites, which were detected as two peaks according to high-pressure liquid chromatography assay. As a result, more than 10% of the initial TOC remained in test microcosms. Eight BPA-degrading bacteria were isolated from river waters and all the isolates accumulated the same metabolites as those accumulated by river water microcosms during BPA degradation. These results suggest that recalcitrant metabolites are produced even if partial degradation of BPA can proceed easily. In some aquatic environments the metabolite(s)-degraders coexist together with the BPA-degraders and they seems essential for the complete degradation or mineralization of BPA.
