FREE, PROTEINACEOUS, AND HUMIC-BOUND AMINO-ACIDS IN RIVER WATER CONTAINING HIGH-CONCENTRATIONS OF AQUATIC HUMUS

Amino acids were determined by GLC analysis at 12 sampling sites along the Williamson River, Oregon [USA], and its principal tributaries at monthly intervals for 2 yr. The 5 most abundant amino acids maintained the relative order Gly > Asp > Ala > Ser .simeq. Glu for the majority of sampling sites and showed no seasonal change. A separation technique using XAD-7 macroreticular resin is described for fractionating total amino acids. At the sampling sites analyzed, .gtoreq. 96% of the dissolved amino acids were associated with dissolved humic material. Correlation of discharge with total amino acid concentration suggests surface runoff as the primary source of amino acids in the river.