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Low Contribution of PbO2-Coated Lead Service Lines to Water Lead Contamination at the Tap
Citation:
Triantafyllidou, S., M. Schock, M. DeSantis, AND C. White. Low Contribution of PbO2-Coated Lead Service Lines to Water Lead Contamination at the Tap. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 49(6):3746-3754, (2015).
Impact/Purpose:
This research establishes that intentional PbO2 scale formation is the most effective water treatment for controlling lead release from lead service lines.
Description:
To determine if field experience corroborates that formation of stable PbO2 coatings on lead service lines (LSLs) provides an effective lead contamination control strategy, lead profile sampling was undertaken at eight home kitchen taps in three US cities (Newport, Rhode Island; Cincinnati and Oakwood, OH) with observed PbO2-coated LSLs. Sampling protocols varied in detail across cities. The variable measured length of premise and LSL piping necessitated collection of different water volumes to capture water in contact with the LSL at each site. After various water standing times (2-101 hours, combining all sites), these LSLs typically released similar or lower peak lead levels (1-18 µg/L) than the lead levels from the respective kitchen faucets (1-130 µg/L), and at least 2 times lower than the lead levels typically reported from Pb(II)-coated LSLs in comparable published sampling studies. Two sampled sites in Cincinnati showed that after prolonged stagnation, lead release from the PbO2-coated LSL increased if the chlorine residual was depleted. Overall, lead release was consistently much lower than that reported for LSLs from studies evaluating Pb(II)-based scales, and was often under 5 µg/L.
