Multi-spectral characterization of natural organic matter (NOM) from Manitoba surface waters using high performance size exclusion chromatography (HPSEC)

Abstract

The main objective of this research was to develop an algorithm that would be able to relate ultraviolet absorbing moieties in potable water to trihalomethanes (THMs) and other water quality parameters. The characterization was carried out using high performance size exclusion chromatography (HPSEC) to separate water samples based on apparent molecule weight (AMW); while the developed algorithm utilized multi-spectral information extracted from 7 Manitoba source waters, and from samples treated with strong base ion-exchange (IX). AMW components between 2.2-4 k Da were strongly associated with the formation of THMs, and more strongly with chlorinated byproducts, determined using Spearman and Pearson coefficients. associations were not improved upon removal of the raw samples from the dataset, indicating that the applied methodology is not specific to IX treatment. Strong associations were also found between initial wavelengths of 226–239 nm and final wavelengths of 257–273 nm, which suggests that absorbing moieties in these ranges are prime precursors in the reaction mechanism to form THMs. A closer look noted that chlorinated THMs were more strongly associated than THMs in general; with brominated byproducts following closely to profiles of UV254 - indicating these parameters are closely related.