AN EVALUATION OF THE METHODS OF MEASUREMENT OF DISSOLVED ORGANIC-CARBON IN SOILS, MANURES, SLUDGES, AND STREAM WATER

Dissolved organic carbon (DOC) from various organic matter sources was measured using spectrophotometric, wet oxidation, and dry combustion methods. The relationship between light absorption at 250 nm and the c oncentration of DOC varied between the sources which is attributed to the difference in the nature of organic compound, as measured by the r elative molecular weight fractions in the DOC samples. Wet oxidation a chieved only a partial oxidation of the DOC and the extent of oxidatio n varied between the sources. Dry combustion achieved the complete rec overy of DOC, Both air drying and oven drying increased the concentrat ion of DOG; whereas freeze drying had no effect on the concentration o f DOG. DOC concentration increased with an increase in pH.