PARENT SESSION

1B+C Abiotic Transformation
Hall 9
8:30 AM - 12:30 PM, Monday, 28 April 2003
Chair: Peijnenburg, W.¹, ¹
Co-chair: Jafvert, C.T.², Gombar, V.K.³, ^{2 3}

(MO9/7) Assessing environmental persistence of polar pollutants - The need to consider interaction of biotic and abiotic processes.

Reemtsma, Thorsten¹, ¹ Technical University of Berlin, Sekr KF4, Strasse des 17 Juni 135, 10623 Berlin, Germany, Germany

ABSTRACT- The assessment of the environmental persistence of pollutants is often based on laboratory biodegradation tests under aerobic and, less frequently, anaerobic conditions. Such isolated experiments can be misleading as they neglect interactions between various classes of microorganisms as well as interactions between biotic and abiotic transformation processes. We have investigated transformation processes of different compound classes with the help of modern analytical techniques. Liquid chromatography-mass spectrometry (LC-MS) enabled us to identify transformation products of polar pollutants and, thus, allowed to determine such interactions of (i) different kinds of microorganisms and (ii) of biotic and abiotic reactions in the course of biodegradation experiments. On one hand, these interactions can be productive and render seemingly persistent compounds biodegradable. We have observed this for sulfonated phthalocyanines, where oxidative fission by white-rot fungi [1], abiotic hydrolysis and mineralization by aerobic mixed cultures was observed [2]. On the other hand, abiotic transformation may interfere with a promising biodegradation pathway, as we discovered in the case of anaerobic/aerobic degradation of azo dyes [3]. Here autoxidation reactions of quinoid intermediates formed by anaerobic transformations led to complex structures resistant to aerobic degradation. The concerted transformation of environmental pollutants by different classes of microorganisms and by biotic and abiotic processes need to be understood based on investigations with modern analytical techniques such as LC-MS. And the interaction between biotic and abiotic processes, whether productive or not, need to be considered to correctly assess the persistenceof polar environmental pollutants. [1] Heinfling-Weidtmann A., Reemtsma T, Storm T. and Szewzyk U. (2001) FEMS Microbiol. Lett. 203, 179. [2] Reemtsma T. and Jakobs J. (2001) Environ. Sci. Technol. 35, 4655. [3] Reemtsma T. and Stueber M. (2002) Environ. Sci. Technol., subm.

Key words: bacteria, persistence, white-rot fungi, liquid chromatography-mass spectrometry