Cyto-genotoxicity evaluation of pyroligneous acid using Allium cepa assay

Abstract

Pyroligneous acid (PA) is a highly oxygenated organic condensate obtained by cooling the gases generated from the pyrolysis process. PA has been used in agriculture for several years with multiple beneficial effects, including plant health and yields, pest resilience, and seed germination. It is generally applied to agricultural soils in the dilution of 1:1000 to 1:100, corresponding to 0.1–1% PA concentration. In this study, the cyto-genotoxic potential of PA to Allium cepa meristematic root-tips (where all cells undergo repeated division and form primary root tissues) was examined. Exposure to PA concentrations of 0.1% and above showed a reduction in the mitotic index percentage, and at 5%, a complete arrest in the cell division was recorded. However, chromosomal aberrations at 0.5, 1, and 3% PA were reversible types such as bridges, vagrants, laggards, and multipolar anaphase, with a maximum of only 5.8% chromosomal aberration observed at 3% PA. Comet assay (single-cell gel electrophoresis) for genotoxicity assessment determined using PA exposed A. cepa root tips showed that it was not genotoxic. The absence of cyto-genotoxicity in A. cepa, even at concentrations far above what would be typically encountered in agricultural applications, strongly suggests that PA is unlikely to cause adverse effects on crops and ultimately on the biota and human health.

Keywords:

• Wood vinegar
• pyroligneous acid
• genotoxicity
• cytotoxicity
• chromosomal aberrations
• mitotic index
• comet assay

Disclosure statement

There are no conflicts to declare.

Data availability statement

The data that supports the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

The authors acknowledge the funding under Tech Voucher Program by the NSW Department of Industry in collaboration with Northside Industries Pty Ltd., and the Global Centre for Environmental Remediation, The University of Newcastle, for the laboratory facilities.