ON THE COMPOSITION AND PROPERTIES OF HUMIC SUBSTANCES ISOLATED FROM DEEP GROUNDWATER AND SURFACE WATERS

Fulvic and humic acids were collected from groundwater and surface waters by an isolation procedure utilizing DEAE-cellulose, a weak anion exchange resin. DEAE-cellulose was selected since it can adsorb humics without any pH adjustment of the sampled water (in the pH range 4-8), thus making the method well suited for isolation of groundwater humic substances in the field. Characterization of general parameters (elemental composition, molecular weight, acidity, absorptivity, C-14-age) was performed on these humic substances as well as on humics isolated by other procedures. The humic substances were divided into three categories on the basis of calculated atomic ratios, molecular weights and absorptivity: humic acids (high molecular weight) and fulvic acids (low molecular weight) from groundwater and surface waters, respectively. The similarities of the humics within each group, despite variations in age and origin, support the contention that humic substances have more properties in common than they have differences.