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Investigation into PCB biodegradation using uniformly 14C-labelled dichlorobiphenyl
A Kubátová1, M Matucha, P Erbanová
1Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Isotopes in Environmental and Health Studies
|March 25, 1999
Summary
Biodegradation of polychlorinated biphenyls (PCBs) in soil is complex. This study used radiolabeled PCB 11 with fungi and bacteria, finding minimal mineralization and significant soil binding.
Area of Science:
- Environmental Science
- Microbiology
- Environmental Chemistry
Background:
- Polychlorinated biphenyls (PCBs) are persistent organic pollutants.
- Soil biodegradation of PCBs is challenging due to complex environmental factors.
- Isotope labeling is crucial for tracking xenobiotic fate in ecosystems.
Purpose of the Study:
- To investigate the biodegradation of a low chlorinated PCB congener (PCB 11) in soil.
- To evaluate the efficacy of white rot fungi (Pleurotus ostreatus) and soil bacteria (Pseudomonas species) in PCB 11 degradation.
- To identify major biodegradation products and pathways.
Main Methods:
- Utilized uniformly 14C-labelled PCB congener 11.
- Employed Pleurotus ostreatus and two Pseudomonas species (alone or in consortium).
- Analyzed degradation products using 14CO2 measurement, radio-HPLC, HPLC, GC-MS, and radio-TLC over two months.
Main Results:
- PCB 11 mineralization was less than 0.4%.
- Volatilization of PCB 11 was less than 3.1%.
- Approximately 30% of radioactivity was irreversibly bound to the soil matrix.
- Intermediate metabolites ranged from 2.5% to 10.5%, with 3-chlorobenzoic acid being the major product.
Conclusions:
- Microbial degradation of PCB 11 in soil by the tested fungi and bacteria is limited.
- A significant portion of PCB 11 becomes bound to the soil, indicating persistence.
- Pseudomonas species showed some potential for metabolizing PCB 11, producing 3-chlorobenzoic acid.