Lead and Copper Rule (LCR) compliance monitoring
is intentionally biased toward sites that
exhibit elevated lead rather than elevated copper,
but water utilities, especially those with higher
percentages of newer copper piping, need to be
aware that copper concentrations above the action
level (AL) may be present in their systems. Orthophosphate
doses at sufficient concentrations can
help high-alkalinity groundwater systems (even
those with new plumbing) meet the copper AL.
The theoretical cupric-hydroxide copper-solubility
model predicts that as pipe ages, tenorite or
malachite forms and predominates as the surface
phase, lowering copper levels. Orthophosphate
dosing, however, can prevent the reduction of
copper solubility over years and decades, with the
result that systems which do not use corrosion
inhibitors likely will experience copper levels
lower than what would be achieved with
orthophosphate. Using the information presented
here, water suppliers will be better able to evaluate
the tradeoff between orthophosphate treatment
versus pH and/or alkalinity adjustment to
meet the LCR. Includes 17 references, tables, figures.
| Edition : | Vol. 101 - No. 7 |
| File Size : | 1
file
, 920 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 07/01/2009 |
