Cellular damages in the Allium cepa test system, caused by BTEX mixture prior and after biodegradation process

• Published in: Chemosphere (Oxford) 2011-09, Vol.85 (1), p.13-18
• Main Authors: Mazzeo, Dânia Elisa Christofoletti, Fernandes, Thaís Cristina Casimiro, Marin-Morales, Maria Aparecida
• Format: Article
• Language: English
• Subjects: Allium cepa; Animal, plant and microbial ecology; Applied ecology; Bacteria - metabolism; benzene; Benzene - metabolism; Benzene - toxicity; Benzene Derivatives - metabolism; Benzene Derivatives - toxicity; biodegradation; Biodegradation, Environmental; Biological and medical sciences; BTEX (benzene, toluene, ethylbenzene, xylene); Chromosomal aberration; Chromosome Aberrations; culture media; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; General aspects; Genotoxicity; groundwater; groundwater contamination; meristems; Micronucleus; Mutagenicity; Mutagenicity Tests; Mutagens - metabolism; Mutagens - toxicity; Onions - cytology; Onions - genetics; petroleum; Petroleum - metabolism; Petroleum - toxicity; Petroleum derivatives; roots; seeds; toluene; Toluene - metabolism; Toluene - toxicity; volatile organic compounds; xylene; Xylenes - metabolism; Xylenes - toxicity
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2011.06.056

► Effects of BTEX, prior and after biodegradation, evaluated in Allium cepa test system. ► BTEX is genotoxic and mutagenic for Allium cepa cells, even at low concentrations. ► A. cepa is an efficient bioindicator of cellular damages induced by BTEX. ► Bacterial biodegradation process degrades BTEX and decreases its toxic action. Petroleum and derivatives have been considered one of the main environmental contaminants. Among petroleum derivatives, the volatile organic compounds benzene, toluene, ethylbenzene and xylene (BTEX) represent a major concern due to their toxicity and easy accumulation in groundwater. Biodegradation methods seem to be suitable tools for the clean-up of BTEX contaminants from groundwater. Genotoxic and mutagenic potential of BTEX prior and after biodegradation process was evaluated through analyses of chromosomal aberrations and MN test in meristematic and F1 root cells using the Allium cepa test system. Seeds of A. cepa were germinated into five concentrations of BTEX, non-biodegraded and biodegraded, in ultra-pure water (negative control), in MMS 4×10−4M (positive control) and in culture medium used in the biodegradation (blank biodegradation control). Results showed a significant frequency of both chromosomal and nuclear aberrations. The micronucleus (MN) frequency in meristematic cells was significant for most of tested samples. However, MN was not present in significant levels in the F1 cells, suggesting that there was no permanent damage for the meristematic cell. The BTEX effects were significantly reduced in the biodegraded samples when compared to the respective non-biodegraded concentrations. Therefore, in this study, the biodegradation process showed to be a reliable and effective alternative to treat BTEX-contaminated waters. Based on our results and available data, the BTEX toxicity could also be related to a synergistic effect of its compounds.