Burning logs and the comet assay

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• Created: Wednesday, 09 November 2016 15:44

Scientists from University of Eastern Finland, Kuopio were inspired by statistics from the world health Organization to investigate particulate emissions from the combustion of birch, beech, and spruce logs.  According to the World Health Organization, particulate emissions from the combustion of solid fuels caused more than 110,000 premature deaths worldwide in 2010.

In developed countries, log wood combustion is one of the most prevalent form of residential biomass heating.  However, relatively little is known about how the type of wood logs used in furnaces influences the chemical composition of the particulate emissions and their toxicological potential.

The researchers burned logs of birch, beech and spruce (which are used commonly as firewood in Central and Northern Europe) in a modern masonry heater.  Then, they compared particulate emissions to those from an automated pellet boiler fired with softwood pellets.

The investigators determined the chemical composition (elements, ions, and carbonaceous compounds) of the particulate emissions with a diameter of less than 1 µm and tested:

• cytotoxicity,
• genotoxicity, (note: comets were analyzed with Comet assay IV software, Perceptive Instruments an Instem company, UK).
•  inflammatory potential,
•  and ability to induce oxidative stress in a human lung epithelial cell line.

It was reported that the chemical composition of the samples differed significantly, especially with regard to the carbonaceous and metal contents. Also the toxic effects in the tested endpoints varied considerably between each of the three log wood combustion samples, as well as between the log wood combustion samples and the pellet combustion sample.

Due to the difference in the toxicological potential of the samples in the various endpoints, the researchers were able to conclude that the involvement of different pathways of toxicity was dependent on the chemical composition.  The investigation showed that all three emission samples from the log wood combustions (birch, beech, and spruce) were considerably more toxic in all endpoints than the emissions from the pellet combustion.

Full experimental information, please refer to the original publication:
Particulate emissions from the combustion of birch, beech, and spruce logs cause different cytotoxic responses in A549 cells, Environmental Toxicology First published: 28 September 2016, S Kasurinen, P. I. Jalava, M. S. Happo, O Sippula, O Uski, H Koponen, J Orasche, R. Zimmermann, J. Jokiniemi, M-R Hirvonen,