Brass fittings as a source of lead and nickel in drinking water. Stage 3 Long term testing April 2015 to March 2016

Abstract

Metal leaching from pipes and fittings into drinking water has been an issue in the UK for several decades, particularly as standards have progressively tightened (the Prescribed Concentration Value (PCV) for lead reduced to 10 µg/l from 25 µg/l in December 2013). This study has examined the leaching of lead, nickel and other metals of interest from UK brass fittings and US low lead fittings in hard and soft water, with and without phosphate dosing. In Stage 1, laboratory and short term (up to 6 month) field experiments on lead leaching were undertaken on a range of brass fittings. In Stage two, longer-term (up to 2 years) lead and nickel leaching characteristics were examined together with experiments on the removal and addition of phosphate dosed water. Stage three, reported here, has continued the study of the long term leaching characteristics of lead and nickel from the brass fittings (up to 3 years including stages 1 and 2) and other metals of interest (Al, Cu, Zn, Fe & Mn), The overall findings show that metal leaching decreases with time in both hard and soft waters.  In non-phosphate dosed waters some individual brass fittings and combinations of fittings can potentially cause failures to Random Daytime Sample for lead and nickel, especially when new or following periods of stagnation. Phosphate dosing was shown to be an effective way of suppressing metal leaching (particularly lead, nickel, copper and zinc) from brass fittings.

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Supporting Material