A Comprehensive Perspective of Drinking Water Quality

Assessment of Lead in Drinking Water from Multiple Drinking Water Sampling Programs for a Midsize City

“…Data from the customer-requested sampling and LCR sampling were analyzed for statistically significant changes in lead concentrations after the introduction of orthophosphate in 2019, which was expected to improve corrosion control. It is important to note that the optimization of orthophosphate dosing can take years, and lead concentrations can continue to decrease after dose optimization. ,, LCR samples and customer-requested samples after the introduction of orthophosphate were expected to be lower, and the 90th percentile concentrations in the LCR data would be expected to be below the EPA action level once corrosion control was optimized. Table , far right column, describes how the available data from each data source were divided into pre- and post-orthophosphate introduction data sets.…”

Estimating Lead Concentrations in Drinking Water after Stagnation in Lead Service Lines Using Water Quality Data from across the United States

“…Because 5th liter lead concentrations were not reported in CCRs, sequential sampling data from 10 prior studies were tabulated (Table ) for comparing calculated equilibrium lead concentrations with concentrations observed in different parcels of water. − ,,,,, Table includes 1st, 5th, and highest lead concentrations with plumbing configurations from 31 sequential sampling events in 17 locations with unique water quality conditions (pH, alkalinity, and orthophosphate). If a study included 5th liter lead for several sampling events with the same water quality, the highest 5th liter lead was listed.…”

“…A parcel of water stagnating inside of a lead pipe can reach equilibrium with the pipe scales and can also carry any detached particulate lead based on the physical stability of the scale layer. Predicted dissolved lead concentrations in equilibrium with dominant lead-containing solids in pipe scales have been used to understand the dynamics of lead release in LSLs. − Limitations in the solubility model resulting in discrepancies between the scales predicted to form and those actually seen in the LSLs have also been noted . While many studies have observed the predicted solid as the most dominant phase of lead inside the pipe, − ,− several have shown a high probability of multiple phases co-existing within an LSL. ,, Hydrocerussite (Pb 3 (CO 3 ) 2 (OH) 2 ) and cerussite (PbCO 3 ) are the most commonly seen phases of lead­(II)-based solids along with litharge (PbO). ,,,− Lead phosphate solids can occur only in phosphate-receiving systems. ,,, …”

Release and migration of Pb from Pb(ii) and Pb(iv) compounds in the presence of microbiological activity

“…Coliform bacteria 14 and various heavy-metal tolerant microbial species have been detected in recovered Pb service lines, 15 and controlled lab/pilot-scale studies have shown that biofilms can form on Pb coupon/pipe surfaces and stored Pb. 16–19 In one study, the numbers of gene copies found on Pb pipe surfaces were comparable to those from PVC and galvanized steel surfaces. 17…”