oa Geochemical Alterations of Organic Matter During Wildfire

Wildfires are considered a notable ecological event that affects the surroundings, leading to terrestrial ecosystem degradation. Besides climate change, wildfire incidents have been on the rise on a global scale. Because of plant combustion, many health concerning organic pollutants like polyaromatic hydrocarbons (PAHs), many of which are carcinogenic, are produced. The aim of this research was to study the chemical changes of organic matter during wildfire.

A total of 27 samples of plant tissue and ash were collected from wildfire affected site and analysed using gas chromatography-mass spectrometry (GC-MS, py-GS-MS). The samples were analysed for the identification and quantification of organic compounds. For elemental analysis, Total Carbon (TC), Total Organic Carbon (TOC), Total Inorganic Carbon (TIC) and total sulphur (TS) were determined. The samples were also studied under a reflected light microscope to estimate fire temperature.

The results show that phenolic compounds produced during pyrolysis of lignin structure of organic matter can be categorised into three fractions, i.e., volatile phenols, compounds included in pyrolysates and remains of macromolecular. The fractions are driven by fire temperature intensity. It is found that py-GCMS can be applied for analysing the chemical changes caused by wildfire in lignin structure.