Definition: Organic matter in a state of advanced decay, after passing through the stages of COMPOST and PEAT and before becoming lignite (COAL). It is composed of a heterogenous mixture of compounds including phenolic radicals and acids that polymerize and are not easily separated nor analyzed. (E.A. Ghabbour & G. Davies, eds. Humic Substances, 2001).
Anal Chem 49(2):216;1977; Appl Environ Microbiol 1979;38(5):840; Arch Environ Health 31(4):187;1976; Folia Microbiol 21(4):257;1976; Health Physics 32:475;1977