Fluorescence Technology for Drinking‑Water Management


Optical properties measured in the lab were highly correlated to DOC concentrations and THMFP and HAAFP in watershed samples. Similarly, in-situ FDOM sensors provided an excellent proxy for continuous DOC concentration in the Clackamas River, demonstrating great promise as a cost-effective tool to better understand DBP precursor sources, seasonality and trends, and possible management of precursor compounds. Because DOM concentration is a driving factor in the production of DPBs in finished water and a good predictor for DBPFP for all watershed samples, continuous in-situ FDOM measurements are potentially valuable as an early-warning system, and for understanding and possibly forecasting finished-water DBP concentrations. In this study, for example, FDOM was highly correlated with finished-water HAA5 concentrations, thus this relation was used to estimate continuous HAA5 concentrations over time (fig. 24).


Although both laboratory measurements of FDOM and UVA₂₅₄ were effective proxies for DOC concentration (fig. 23 and table 11), measurement of fluorescence has several advantages over absorbance (Henderson and others, 2009; Kraus and others, 2010; Bridgeman and others, 2011). In particular, absorbance measures are more prone to metal quenching and particle interference compared with fluorescence methods, and absorbance requires filtration prior to analysis. The fact that these flat-faced and flow through fluorometers can measure fluorescence directly without filtration is a tremendous advantage. In this study, FDOM produced as high or higher correlations with finished-water DBP concentrations and laboratory DBPFPs compared with more traditional absorbance measures such as UVA₂₅₄ (table 11). This corroborates findings from a similar study of the nearby McKenzie River (Kraus and others, 2010).


First posted February 11, 2013