Premium
Importance of pipe deposits to Lead and Copper Rule compliance
Author(s) -
Schock Michael R.,
Cantor Abigail F.,
Triantafyllidou Simoni,
Desantis Michael K.,
Scheckel Kirk G.
Publication year - 2014
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.5942/jawwa.2014.106.0064
Subject(s) - manganese , lead (geology) , environmental science , copper , corrosion , contamination , metallurgy , geology , materials science , ecology , geomorphology , biology
When Madison, Wis., exceeded the lead action level in 1992, residential and off‐line tests suggested that lead release into the water was more complex than a lead solubility mechanism. Scale analyses (color and texture as well as mineralogical and elemental composition) of five excavated lead service lines (LSLs) revealed that accumulation of manganese (and iron) onto pipe walls had implications for lead corrosion by providing a high‐capacity sink for lead. Manganese that accumulated from source well water onto pipe scales (up to 10% by weight of scale composition) served to capture and eventually transport lead to consumer taps. In addition, manganese sometimes obstructed the predominance of an insoluble (and thus potentially protective) plattnerite [Pb(IV) solid] scale layer. Full LSL replacement in Madison achieved Lead and Copper Rule compliance and a major reduction in lead contamination and exposure, supplemented by unidirectional flushing of water mains and manganese control in the source well water.