This powerpoint presentation begins by presenting a review of causes for concern that include the following:
Pb action level exceedance when coagulant
changed from alum to PACl;
Dodrill & Edwards (1995)- more lead with
higher chloride and lower sulfate;
pH as low as 3.4 at solder surface
(Triantafyllidou, 2007); and,
Triantafyllidou (2007) proved galvanic
corrosion increased Pb release by 16 X. Possible origin of effect is presented, along with a mechanistic study of Patuxent River water. Presentation conclusions indicate the following:
lead solder-copper couples sustained very
high lead levels throughout the study;
low pH measured at anode;
Anions (Cl- and SO<sub>4</sub><sup>2-</sup>) migrate to the lead
anode;
lead sulfate is relatively insoluble, while
chloride complexes lead and increases lead
leaching; and,
increased lead levels correlated with
increased galvanic current;
galvanic effects are very persistent in some
systems; and,
high orthophosphate or high alkalinity do
not eliminate galvanic effects, but can
reduce them. Includes figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.9 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 40 |
| Published : | 11/01/2008 |
