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Water quality-pipe deposit relationships in Midwestern lead pipes
Citation:
Tully, J., M. DeSantis, AND M. Schock. Water quality-pipe deposit relationships in Midwestern lead pipes. JOURNAL OF THE AMERICAN WATER WORKS ASSOCIATION. American Water Works Association, Denver, CO, 1(2):1-18, (2019).
Impact/Purpose:
This research paper will provide new information on the mechanisms of lead release control by corrosion control treatment in 22 Midwestern water systems. The conclusions are that in only a minority of cases were the actual pipe scales responsible for reducing lead release predictable by solubility equilibria of simple lead carbonates and phosphates. Thus, minimization of lead release should be determined by actual utility specific studies and the success of the treatments are best determined by diagnostic tap sampling reflecting water in contact with the different lead sources in premise plumbing and service lines.
Description:
The conventional wisdom of lead solubility has been built over the years by geochemical solubility models, experimental studies, and field sampling of drinking water lead levels by differing protocols. Rarely, have the phases formed in real world drinking water lead service lines (LSLs) been compared to the theoretical predictions. LSL scales from 22 drinking water distribution systems (DWDSs) in US EPA’s Region 5 were evaluated. The pipe scale analysis used multiple analytical methods for compound and elemental composition to compare the observed phases to those predicted by solubility modeling. Only 9 of the 22 systems had LSL scales that followed model predictions. Nine systems contained unpredictable amorphous phases of unknown lead release characteristics at the scale surface. This study concluded that for many systems, appropriate water sampling is needed to determine lead release from LSLs, and pilot studies would usually be necessary to evaluate and optimize corrosion control alternatives.
URLs/Downloads:
Free access through PubMed Central
https://awwa.onlinelibrary.wiley.com/doi/full/10.1002/aws2.1127