Abstract
The seasonal variation of water sample profiles, sourced from two different locations (named Sources A and B), were investigated using excitation-emission matrix (EEM) fluorescence spectroscopy. Subtle spectroscopic differences between the two water profiles were observed within the EEM using principal component analysis (PCA) and fluorescence regional integration (FRI). Each water sample exhibited significant variation in algal/cyanobacterial pigments and humic-like molecules. It was possible to distinguish between water samples taken from Sources A and B. In addition, single value parameters (such as turbidity, temperature, pH, conductivity, and colour) were analysed using multiple one-way Welch's analysis of variance (ANOVA) and was used to observe correlation with EEM fluorescence data, if any. A decrease in contributions from algae and cyanobacteria was found in the water samples between New Zealand autumn (March to June), which infers an increased cyanobacteria and algae activity during warmer months when the water is less acidic. These results highlight the utility of EEM fluorescence spectroscopy, combined with PCA and FRI, as a sensitive, powerful, exploratory tool to characterize components within source water which serve as indicators for water quality and support long-term environmental management.
• Analysis of input streams to treatment plants is critical for quality drinking water.
• Emission excitation spectroscopy may be used to identify pigments and organic matter.
• Principal component analysis (PCA) may be used to further analyse water content.
• Multivariate analysis may be correlated to pH and temperature in the input stream.