title: Impact of treatment on Pb release from full and partially replaced harvested Lead Service Lines (LSLs).
abstract: Release of lead from 80% partially replaced service lines was compared to full lead service lines using harvested-stabilized lead pipes and field brass connectors. After more than a year of stabilization, lead release was consistent with field samples. Over the relatively short duration partial replacement of lead pipe by copper pipe (3 months), generated high lead release, attributed to galvanic corrosion, resulting in a final outcome for lead release that was even worse than for a full lead pipe. Increased lead release was especially evident at higher flow rates. Orthophosphate reduced lead release from full lead pipes by 64%. For partially replaced samples with copper, lead concentrations were unchanged by phosphate dosing at moderate flow (103 ± 265 vs 169 ± 349 μg/L) and were increased to very high levels when sampled at high flow rates (1001 ± 1808 vs 257 ± 224 μg/L). The increase lead release was in the form of particulate lead (>90%). In comparison to the condition without treatment, increased sulfate treatment had little impact on lead release from 100%-Pb rigs but reduced lead release from partially replaced lead pipes with copper. Our results also raise questions concerning protocols based on short 30 min stagnation (as those used in Canada) due to their incapacity to consider particulate lead release generated mostly after longer stagnation.
authors.affiliation: Claro Environmental Technologies & Equipment, 4721 Louis-B.-Mayer, Laval, QC, Canada H7P 6G5. ccartier@claroglobal.com
authors.forename: Clément
authors.initials: C
authors.lastname: Cartier
authors.forename: Evelyne
authors.initials: E
authors.lastname: Doré
authors.forename: Laurent
authors.initials: L
authors.lastname: Laroche
authors.forename: Shokoufeh
authors.initials: S
authors.lastname: Nour
authors.forename: Marc
authors.initials: M
authors.lastname: Edwards
authors.forename: Michèle
authors.initials: M
authors.lastname: Prévost
mesh_terms: D002170:Canada; D003300:Copper / Q000737:chemistry; D003343:Corrosion; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry*; D007855:Lead Poisoning / Q000517:prevention & control; D008669:Metallurgy / Q000379:methods*; D010710:Phosphates / Q000737:chemistry; D010865:Pilot Projects; D011792:Quebec; D012995:Solubility; D013431:Sulfates / Q000737:chemistry; D014481:United States; D014504:Urban Health; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014877:Water Pollution, Chemical / Q000517:prevention & control*; D018508:Water Purification / Q000379:methods*; D060753:Water Quality / Q000592:standards; D014881:Water Supply / Q000032:analysis* / Q000592:standards
chemical_list: D010710:Phosphates; D013431:Sulfates; D014874:Water Pollutants, Chemical; C012036:sodium sulfate; D007854:Lead; D003300:Copper