Influence of natural organic matter on the morphology of corroding lead surfaces and behavior of lead-containing particles

Influence of natural organic matter (NOM) on the morphology of lead surfaces exposed to drinking water and on the properties of lead-containing colloidal particles was explored based on the data of scanning electron microscopy, sequential filtrations, measurements of particle size distributions and electrophoretic potential. It was demonstrated that NOM prevented the formation of cerussite and hindered the growth of hydrocerussite crystals. Measurements of ζ-potential showed that the surface activity was highest for unaltered NOM, while ozonation and chlorination decreased it. The concentrations of soluble lead and tin increased several fold in the presence of NOM, while large colloidal particles of lead and solder corrosion products tended to break down to form smaller fragments. It is suggested that these phenomena are important for understanding of lead release mechanisms in drinking water.