(564d) Understanding Protein Uptake in Water Distribution Systems Using Amino Acids as Exemplar Contaminants

Understanding the fate and transport of a given contaminant within a water distribution system is critical in being able to appropriately respond to an accidental or intentional contamination event. Unfortunately, performing fate and transport studies on every potential contaminant is prohibitively expensive, both in terms of cost and time. A more appropriate solution may lie in defining and examining classes of similar compounds based on smaller functional units. For proteins, the adhesion to pipes in a water distribution system can be predicted based on understanding the behavior of the individual amino acids composing them. Guided by results obtained from molecular simulations of amino acid adsorption to phantom surfaces, we have performed laboratory experiments to probe the sorption/desorption behavior of several amino acids on pipe walls. The amino acid concentrations were monitored in static pipe samples over a period of time to establish equilibrium concentrations and adsorption parameters. The hydrophobicity of the amino acid and the size of the organic side chains influenced the percentage of amino acid adsorbed to the pipe surfaces. A variety of pipes (PVC, copper, and concrete lined ductile iron) were used to examine the role pipe material played in amino acid uptake. Our results are compared to previously reported trends in binding energies as predicted by molecular modeling over a phantom surface.