WATER-SOLUBLE ORGANIC COMPOUNDS FROM BIOCHARS AND FOREST FIRES

The application of biochar to soil has been proposed as a long-term sink for atmospheric carbon dioxide in terrestrial ecosystems while also providing improved soil fertility and increased crop production with concurrent energy from and constructive use for waste biomass. To investigate effect of large-scale incorporation of biochar into agricultural soils on surface and ground waters, a series of laboratory-produced and commercial pine biochars were extracted with water and analyzed by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry to determine organic compounds that may elute from the biochars under environmental conditions. Water samples from downstream of burned areas of pine forest were also analyzed. Some typical organic compounds found in the water extracts of low temperature pine chars were guaiacol (a component of pine tar), syringol (found in wood smoke), vanillin, ethyl vanillin, isovanillic acid, and levoglucosan, while none of these were found in water extracts of high temperature laboratory chars or from local commercial chars. Several of these pine-related compounds were found downstream of burned areas, including guaiacol, vanillin, ethyl vanillin, and homovanillyl alcohol.