Evaluation of Nanoparticles and Colloids in a Public Water Supply from Well-Head to the Consumer Tap

Abstract

Nanoparticles (NP) (<100nm in one dimension) are ubiquitous in low temperature environments including surface and groundwater. NP are extremely reactive due to large ratio of surface area to volume. Synthetic NP used in industry are surviving wastewater treatment and showing up in surface waters, some of which are used for public water supplies. NP form surface complexes with metals in solution. The stability of surface complexes is pH dependent. Formation of complexes always increases metal solubility. Therefore, complexes increase metal transport ability. Natural NP have a variety of compositions. Particles sampled from the Eau Claire well field articles predominantly contain Ca, Si, Mg with several minor constituents. Each well has a unique compositional signature. NP chemistry evolves during the treatment process. Ca is increased, while Fe and Mn are reduced during the treatment at the Eau Claire water plant. The Eau Claire municipal water does not carry priority metals.