Professor Southern Illinois University Edwardsville
Lead leaching from water service pipelines is a prominent problem faced by many water utilities. A research was conducted to investigate how major water quality parameters affected the rate of lead leaching from lead-based water service pipelines into potable water. The studied water parameters included hardness, alkalinity, pH and chloramine residual. The tested specimen of lead pipes lost the scaling on their interior surface, resulting in direct contact of water with the lead of pipe material. Each tested lead pipe was placed in a sealed beaker that was filled with the tested water. The water was changed out on a Monday, Wednesday, and Friday schedule for a six-month of testing period. The lead pipes were weighted at set intervals. The water quality that served as control before contacting the lead pipes had hardness of 107 mg/L CaCO3, alkalinity of 38 mg/L CaCO3, pH of 9.45, and chloramine residual of 2.29 mg/L. One water quality parameter was adjusted for each tested lead pipe specimen. Results revealed that parameters that affected lead leaching the most, in descending order, were alkalinity decreased, chloramine decreased, pH decreased, alkalinity increased, and hardness. It was found that decreased alkalinity resulted in 1,700 ppb of lead concentration that was 28 times higher than that in the control sample, decreased chloramine resulted in a significant increase in lead concentrations that warrants further study about how chloramine affects lead leaching. Findings from this study could benefit water utilities to develop appropriate strategy for the control of lead leaching.
