Organic tracers from wild fire residues in soils and rain/river wash-out

The molecular compositions and alteration products of the major organic components in soils and litter subjected to controlled or wildfire burning, and subsequent erosion by rain and river transport have been determined by GC-MS. The major compound groups imparted to soils include n-alkanoic acids, n-alkanes, n-alkanols, phytosterols, and terpenoids. Biomarker tracer analysis indicates that organic compounds remain as internal lipid components of char and heavy particles and are deposited onto soil during wildfire and prescribed burning. The process of rain erosion and river transport releases some of these internal components into the surroundings where they are further subjected to biological alteration. The distributions and abundances of homologous compound series coupled with biomarker tracer analysis provides a chemical fingerprint which is useful for identifying the single or multiple plant species contributing organic matter by both thermal (burning) and biological processes. Such fingerprints are useful for tracking soils which are transported in the atmosphere by wind as suspended particles in dust storms and on land by rain erosion to rivers.