Effects of trace metals on chloraminated disinfection byproduct formation of drinking water biofilms

Abstract

The use of disinfecting chemicals on public water supplies is a practice conducted around the world today. Disinfectants such as chlorine, chloramine, and ozone can be added to a water supply to eliminate any bacteria and waterborne diseases in the water. Studies have found that these chemicals can also oxidize natural organic matter in the water, creating disinfection byproducts (DBPs). Presently, hundreds of DBPs have been identified, both volatile and nonvolatile. Due to the potential harms of these DBPs, countries have established regulations that limit their concentration in water and pushed for research to improve our understanding of their formation. Recent research has found that the presence of metal ions in treated water can influence the types and concentration of DBPs formed. The aim of this study was to determine the influence trace metals have on the production of DBP precursors from bacterial isolates. The samples tested in this study showed that metal's do have influence over DBP formation. When compared against a set of control samples, samples with the addition of metal ions had increase and decreased concentrations of the targeted DBPs. Some DBPs such as chloroform that were not present in the control samples, were present in high concentrations in samples with metal additives. Chloropicrin was present in the control sample, and with the addition of various metals, such as Mg, the formation was increased. The addition of metals such as Fe and Mn resulted in no formation of chloropicrin in solution.