CHARACTERISTICS OF HUMIC AND FULVIC-ACIDS IN ARABIAN SEA SEDIMENTS

Humic and fulvic acids isolated from some of the shelf, slope and offs hore sediments of the Arabian Sea were studied. The molecular weight, functional groups, elemental composition and infrared spectra were exa mined. Humic substances, dominated by humic acids contributed 22-53% o f the sedimentary organic matter. The humic acids in turn are dominate d by the high molecular weight fraction (>300000). A major portion of fulvic acids was mostly present as <10000 molecular weight fraction. T he elemental composition ranges of HA and FA are C: 60.3-50.3%, H: 6.9 -5.7% and N: 4.1-2.0% and C: 46.5-28.1%, H: 8.9-3.6% and N: 4.8-1.6% r espectively. The C/N ratio points out to the dominance of terrigenous matter in the formation of humic substances. The infrared spectra of h umic acids and fulvic acids although similar exhibited perceptible var iations that could be interpreted in terms of changing phenolic, carbo xylic and nitrogen contents.