[Experimental study on the behaviour of water in contact with pipes containing lead]
Etude experimentale des facteurs qui conditionnent le comportement de l'eau au contact des canalisations qui contiennent du plomb
Abstract
An experimental study was carried out on the behaviour of water with a low mineral content when in contact with pipes containing lead. Two 20m long circuits were used, one in lead, the other in copper with 10 lead-soldered joints. The analysis of the first water drawn off after various contact times ranging from 2 to 65hr showed that the main factors that affect lead dissolution are the pH, the alkalinity and the organic matter concentration in the water. Lead particles form in the few first hours, before the various forms of lead reach the solubility limit. When water is drawn from the pipe, the lead concentration decreases progressively. The contamination rates produced by a constant flow through the lead pipes were also measured. This showed that, if the pH and alkalinity of the water are low, service pipes or internal networks partly in lead, could cause a high risk to exceeding 10mug/l. Lead -solder joints also present a considerable risk of contaminating the first water drawn off.