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Impact of iron‐rich scale in service lines on lead release to water
Author(s) -
Bae Yeunook,
Pasteris Jill D.,
Giammar Daniel E.
Publication year - 2020
Publication title -
awwa water science
Language(s) - English
Resource type - Journals
ISSN - 2577-8161
DOI - 10.1002/aws2.1188
Subject(s) - lepidocrocite , magnetite , corrosion , iron oxide , lead (geology) , metallurgy , coating , oxide , tap water , chemistry , service life , materials science , chemical engineering , environmental science , environmental engineering , goethite , nanotechnology , geology , composite material , adsorption , engineering , organic chemistry , geomorphology
Total iron and total lead concentrations were correlated in water that had stagnated in laboratory‐scale experiments with sections of 10 harvested lead service lines (LSLs) from Providence, Rhode Island. One of these sections had much greater lead release and pH decrease during stagnation, and the inner surface of this service line had a thick coating of iron oxide scale. The iron‐rich scale was composed of coarse‐grained iron oxides (lepidocrocite and magnetite) covered with a thin lead‐bearing layer (hydrocerussite). Complementary batch experiments with pure iron oxides found that their surfaces accelerated the oxidation of Pb(II) from hydrocerussite, which produced PbO 2(s) and decreased the pH. While the findings presented are for LSLs from Providence, the co‐occurrence of iron oxides and lead corrosion products is widespread. The results highlight the importance of considering iron corrosion when evaluating processes that control lead concentrations in tap water.