Components Testing - Effects of Changing Disinfectants and Other Water Quality Parameters on Lead and Copper Release

摘要

New and used meters and stop valves were provided by participating utilities (Seattle Public Utilities and DC Water) and tested using local tap water to measure leaching of lead and copper upon exposure to changing disinfectants (free chlorine to chloramines and vice versa) and other controlled water quality conditions (pH, alkalinity, phosphate). The tests were conducted by a “fill, stand, dump, and refill” procedure. Components were tested at the same time, in the same facilities, and using the same water quality as pipe loop testing that was conducted as part of this research project. Results showed that high lead and copper levels were measured initially from both new and used components, but levels declined rapidly during baseline tap water conditions. In the absence of phosphate, lowering pH and/or switching from chloramines to free chlorine resulted in higher metals levels. The lowest lead and copper levels were measured when phosphate was present. After an initial period of conditioning, results from components testing provided supporting data consistent with copper alloy pipe loop testing results.