Humic and fulvic acids in sediments of the Hooghly estuary and some coastal areas in the northern Bay of Bengal

16-20Humic substances separated from the sediments of the Hooghly estuary and some coastal stations, were studied. The major fraction of humic acids was extracted by 0.05 M alkali solution whereas the major fraction of fulvic acids required 0.5 M alkali solution. Humic acids were the major fraction in the riverine region whereas fulvic acids comprised the major fraction of humic substances in the estuarine region. Carbon to nitrogen ratio was characteristic of the allochthonous organic matter. Of the organic matter 40-69% was found to be associated with humic substances