Lead and copper release in distribution systems is influenced by physical, chemical and biological characteristics of the water and what other factor?

• A. The metal surface
• B. Pipe length
• C. Water source
• D. Chlorine dose

Answer: (A)

Lead and copper release in a distribution system is driven by how the water interacts with the pipe’s interior metal surface. The pipe surface itself is the source and mediator of metal dissolution, so its condition largely determines how much metal enters the water. If the surface has a stable protective film or scale and the water chemistry supports passivation, metal release stays low. If the surface is damaged, rough, or heavily corroded and lacks protection, metals dissolve more readily, especially under aggressive water conditions (low pH or low alkalinity, high oxidants, stagnant water). Water chemistry can influence the surface reactions, but the key factor that sets the potential for lead and copper release is the state and composition of the metal surface itself, which is why corrosion control aims to create and maintain protective surface films on the pipes.