Utility experience under the Lead and Copper Rule was examined to provide improved insight into corrosion control. Average 90th percentile lead concentrations were highest in very low alkalinity water (<30 mg/L as CaCO3) at utilities that did not use inhibitors; lead release was significantly reduced at higher alkalinities. Average lead releases were 20-90 percent lower for utilities using phosphate inhibitors (orthophosphates, polyphosphates, and blended phosphates) in very low alkalinity waters than for utilities not using inhibitors. At alkalinities of 30-74 mg/L as CaCO3 and at pH values > 7.40, it appeared that polyphosphate inhibitors had adverse effects on average lead release. Utilities with pH < 7.40 and high alkalinity waters had the highest copper concentrations. Phosphate inhibitors were usually beneficial in mitigating copper release; however, most benefits were at utilities with pH < 7.80 and alkalinity > 90 mg/L as CaCO3. Inhibitors appeared to adversely affect average copper release in some pH and alkalinity categories. Includes 23 references, tables, figures.
| Edition : | Vol. 87 - No. 7 |
| File Size : | 1
file
, 890 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 07/01/1995 |
