Spectroscopic characterization of fulvic acid fractions of a contaminated groundwater

Two fulvic acid (FA) samples taken from a former gas production facility in the Southwest of Germany were characterized using advanced fluorescence te chniques. Steady-state fluorescence (fluorescence excitation, synchronous f luorescence) as well as time-resolved fluorescence were applied. Distinct d ifferences between the sample B22 FA taken within the contamination plume a nd the sample B53 FA taken downstream were found. Comparison with a model c ompound for metabolites and humic substances revealed that due to the downs tream passage the characteristics of the dissolved organic matter became mo re humic-like. The assignment of single classes of compounds in the sample B22 FA is discussed in terms of their synchronous fluorescence spectra and fluorescence decay time distribution.