ABSTRACT
Humic acid, fulvic acid, tannins, and lignins occur abundantly throughout the aquatic environment in marshes, lakes, streams, rivers, and to a lesser extent the sea. Dissolved humic material can be divided into two main fractions, humic acid and fulvic acid, based on their solubility in acid and alkali. Humic acid is that fraction that is soluble at pH 9 but insoluble at pH 2, whereas fulvic acid is that fraction which is soluble at pH 2 and at pH 9. Natural organic compounds, including humic substances tannins, lignins, amino acids, phenols, carbohydrates, and hydrocarbons are widely distributed throughout the environment. Living systems consist of high molecular weight polymeric materials which on degradation break down into yellow colored substances that we frequently find in our surface waters. Humic substances are known to combine with many organic compounds including pesti cides. The traditional method of fractionating extracted humic material into fulvic and humic components was based on solubility at different pH values.
