Copper Release in Drinking Water Due to Internal Corrosion of Distribution Pipes

The present paper deals with water quality modification during its stagnation in copper distribution pipes caused by electrochemical corrosion processes. Copper is chosen as plumbing material because of its wide use in drinking water distribution systems all around the world, and because of its recognized toxicity at high dosages. Several experiments are developed, varying water composition and stagnation length, to ascertain the dependence of copper release on both parameters. The effect of different concentrations of bicarbonates, sulphates and phosphates on metal release is studied, assuming stagnation periods ranging from 15 to 90 minutes. The corrosion potential of the metal surface during stagnation episodes is also monitored to verify the existence of a direct correlation between this potential at the end of each stagnation episode, and the corresponding total dissolved copper concentration in the stagnating water. The correlation allows to quantify copper release in drinking water, measuring the corrosion potential, drastically reducing, in this way, the cost of water quality monitoring.