Fluorescence characterization of the interaction of Al3+ and Pd2+ with Suwannee River fulvic acid in the absence and presence of the herbicide 2,4-dichlorophenoxyacetic acid.

In an effort to understand the role of environmental metal ions in the interaction of charged pesticides with humic substances, a fluorescence study of the interaction of the widely-used herbicide 2,4-dichlorophenoxyacetic acid (DCPAA) with Al(3+) and Pd(2+) and Suwannee River fulvic acid (SRFA) was undertaken. Initial fluorescence experiments on binary solutions clearly indicated that both Al(3+) and Pd(2+) strongly interact with both SRFA and DCPAA when alone in solution with the metal ion. Titrations of SRFA with Al(3+) at pH values of 4.