Distribution of dissolved organic matter in freshwaters using excitation emission fluorescence and Multivariate Curve Resolution.

Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) method with the trilinearity constraint is proposed for the analysis of excitation-emission fluorescence data from Dissolved Organic Matter (DOM) in fresh water natural systems, and the results obtained are compared with those obtained with PARAFAC. The effects of different number of components and constraints on the stability of the proposed models are compared. MCR-ALS is shown to be an effective way to characterize and resolve DOM sources in natural fresh water systems from EEM data, with good correlation with experimentally measured DOM concentration values. MATLAB georeferenced mapping is used to illustrate the geographical distribution of resolved DOM contributions. MCR-ALS resolved EEM spectra are used to recognize the corresponding chemical groups assigned to possible DOM sources. Relationships between human activities and the environmental situation of the river system are discussed from these possible DOM sources.