Formation of Toxic 2-Nonyl-p-Benzoquinones from 伪-Tertiary 4-Nonylphenol Isomers during Microbial Metabolism of Technical Nonylphenol

详细信息    查看全文

• 作者：Fr茅d茅ric L. P. Gabriel ; Mauricio Arrieta Mora ; Boris A. Kolvenbach ; Philippe F. X. Corvini ; Hans-Peter E. Kohler
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：June 5, 2012
• 年：2012
• 卷：46
• 期：11
• 页码：5979-5987
• 全文大小：343K
• 年卷期：v.46,no.11(June 5, 2012)
• ISSN：1520-5851

文摘

In many environmental compartments, microbial degradation of 伪-quaternary nonylphenols proceeds along an ipso-substitution pathway. It has been reported that technical nonylphenol contains, besides 伪-quaternary nonylphenols, minor amounts of various 伪-H, 伪-methyl substituted tertiary isomers. Here, we show that potentially toxic metabolites of such minor components are formed during ipso-degradation of technical nonylphenol by Sphingobium xenophagum Bayram, a strain isolated from activated sewage sludge. Small but significant amounts of nonylphenols were converted to the corresponding nonylhydroquinones, which in the presence of air oxygen oxidized to the corresponding nonyl-p-benzoquinones鈥攜ielding a complex mixture of potentially toxic metabolites. Through reduction with ascorbic acid and subsequent analysis by gas chromatography鈥搈ass spectrometry, we were able to characterize this unique metabolic fingerprint and to show that its components originated for the most part from 伪-tertiary nonylphenol isomers. Furthermore, our results indicate that the metabolites mixture also contained several 伪, 尾-dehydrogenated derivatives of nonyl-p-benzoquinones that originated by hydroxylation induced rearrangement, and subsequent ring and side chain oxidation from 伪-tertiary nonylphenol isomers. We predict that in nonylphenol polluted natural systems, in which microbial ipso-degradation is prominent, 2-alkylquinone metabolites will be produced and will contribute to the overall toxicity of the remaining material.