Manganese Deposition in Drinking Water Distribution Systems

Gerke TL, Little BJ, Barry Maynard J. Manganese deposition in drinking water distribution systems. The Science of the total environment. 2015 Sep 23;541:184-193. doi: 10.1016/j.scitotenv.2015.09.054.

This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn3+ and Mn4+) and hollandite (Mn2+ and Mn4+), and a Mn silicate, braunite (Mn2+ and Mn4+), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality.

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