Granular activated carbon was recently shown to effectively remove natural organic matter (NOM) precursor material and lower the formation of regulated and unregulated disinfection by products (DBPs) at full-scale drinking water treatment plants.<sup>1</sup> However, it is currently unknown whether point-of-use (POU) activated carbon (AC) filters remove a broad range of regulated and unregulated DBPs formed in treated drinking water. In this study, the efficiency of a Brita® pitcher filter was investigated for removing 57 priority unregulated DBPs from tap water, including halonitromethanes, haloacetamides, haloacetonitriles, haloacetaldehydes, and iodo-acetic acids. A highly sensitive gas chromatography (GC)-mass spectrometry (MS) method was used to measure them.<sup>2</sup> To simulate realistic use, Brita® pitcher filters were tested at various ages (at the beginning, middle, and end of their lifetimes) for samples of unspiked tap water and samples of nanopure water spiked with a high and low concentration of DBPs; all experiments were conducted in triplicate. Results demonstrate that DBPs in every investigated class show significant reduction at the beginning of the filter’s lifetime, with a drop in efficiency as the lifetime of the filter progresses. For example, for the high spike level, the Brita filter achieved 64%, 40%, and 33% removal from the beginning (2L), middle (45L), and end (90L) of their lifetimes, respectively. Interestingly, at the end of the filter’s lifetime, concentrations for some DBP classes increase, likely due to breakthrough from the AC column. This project gives us a better understanding of the impact that home-use activated carbon filters have reducing exposure to DBPs from drinking water.

Emerging unregulated disinfection by-products: Can Brita filters remove them?

ACS Fall 2021

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