Laboratory, pilot, and field data collected support the theoretical "cupric hydroxide" copper
solubility model. For the short time frames inherent in laboratory and pilot studies of copper
solubility and in initial field monitoring for the LCR from Tier 1 soldered copper sites, cupric
hydroxide or a very microcrystalline tenorite should be the dominant solid phase, whereas over
time, the pipe will "age" and tenorite or malachite will form and predominate as the surface
phase. Orthophosphate treatment will initially lower copper levels, when applied in the proper
pH range. Unlike systems optimizing pH and DIC adjustment, the orthophosphate-treated
systems tend to see stable copper levels, rather than the "aging" phenomenon. Given enough
time (years to decades), in similar systems without orthophosphate, the copper levels will
probably eventually drop below what would be achieved with orthophosphate. Systems
employing orthophosphate see rapid reductions initially, but the stabilization long-term could be
difficult to overcome if there are later issues with more stringent limits on phosphate or copper
levels in wastewater.
Compliance monitoring required for the LCR is biased towards sites that may exhibit elevated
lead levels rather than elevated copper levels. Current targeting will likely show that Cu levels
will continue to decline, so the discrepancy between the copper levels covered under LCR
monitoring and that in the locations with potential for highest exposure to copper will increase
over time. Includes 7 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 530 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 26 |
| Published : | 06/01/2006 |
