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Effect of free chlorine and chloramines on lead release in a distribution system
Author(s) -
Vasquez Ferdinand A.,
Heaviside Robert,
Tang Zhijian Jason,
Taylor James S.
Publication year - 2006
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 - 10.1002/j.1551-8833.2006.tb07596.x
Subject(s) - chloramine , chlorine , chlorine dioxide , chemistry , reduction potential , environmental chemistry , groundwater , inorganic chemistry , organic chemistry , engineering , geotechnical engineering
Total lead release in the presence of free chlorine and chloramine residuals was investigated in drinking waters produced from ground, surface, desalinated, and blended water sources. For desalinated and blended finished waters, more total lead was released in the presence of chloramine than in the presence of free chlorine; for finished groundwater and surface water, however, no statistical differences in total lead release were found. Finished water oxidation‐reduction potential (ORP) differed by residual type but was equivalent by source and not affected by the addition of 100 mg/L of sulfates or chlorides. ORP measurement and development of Pourbaix diagrams showed that lead dioxide was the controlling solid phase in the presence of chlorine, and hydrocerussite was the controlling solid phase in the presence of chloramine. Lead dioxide is less soluble than hydrocerussite, which mechanistically accounted for the lower lead release in the presence of free chlorine.