Inhibition of release of lead into water owing to galvanic corrosion of lead solders

Studies of Pb/Sn solder embedded in copper plates exposed to tap water (TW) and well water (WW) have shown the release of unsafe levels of Pb into water owing to galvanic corrosion of the solder. The addition of small amounts of sodium silicate (40 ppm) reduced the levels of Pb released in TW and WW to below the detection limits. Surface analysis of the deposits on the samples showed the presence of copper silicate and calcium carbonate on solder samples exposed to TW and WW containing silicate respectively. The practical implication of the work is that the addition of a small amount of sodium silicate at the main water source of old buildings with lead in the plumbing system can alleviate the contamination of water by lead which is known to be a health hazard.