title: Impact of water treatment on the contribution of faucets to dissolved and particulate lead release at the tap.
abstract: A field study was performed in a building complex to investigate the extent and sources of lead (Pb) release in tap water and brass material was found to be the main contributor in the very first draw (250 mL). Based on these results, a pilot installation was built to study Pb leaching from old and new faucets in the presence and absence of a connection to Cu piping. Four water quality conditions were tested: i) no treatment; ii) addition of 0.8 mg P/L of orthophosphate; iii) pH adjustment to 8.4; and iv) adjustment to a higher chloride to sulfate mass ratio (CSMR; ratio from 0.3 to 2.9). Pb concentrations in samples taken from the faucets without treatment ranged from 1 to 52 μg/L, with a mean of 11 μg/L. The addition of orthophosphate @ 0.8 mg P/L (OrthoP) was the most effective treatment for all types of faucets tested. On average, OrthoP reduced mean Pb leaching by 41%, and was especially effective for new double faucets (70%). In the presence of orthophosphates, the relative proportion of particulate Pb (Pbpart) (>0.45 μm) increased from 31% to 54%. However, OrthoP was not efficient to reduce Zn release. The higher CSMR condition was associated with greater dezincification of yellow brass but not of red brass. Corrosion control treatment influenced Pb concentration equilibrium, directly impacting maximal exposure. Significantly higher Pb release (3 fold) was observed for 1 of the 8 faucets connected to Cu exposed to high CSMR water, suggesting the presence of galvanic corrosion.
authors.affiliation: École Polytechnique de Montréal, Civil, Geological and Mining Engineering, P.O. Box 6079, Station Centre-ville, Montreal, Quebec, Canada H3C 3A7. clement.cartier@polymtl.ca
authors.forename: Clément
authors.initials: C
authors.lastname: Cartier
authors.forename: Shokoufeh
authors.initials: S
authors.lastname: Nour
authors.forename: Benoit
authors.initials: B
authors.lastname: Richer
authors.forename: Elise
authors.initials: E
authors.lastname: Deshommes
authors.forename: Michèle
authors.initials: M
authors.lastname: Prévost
mesh_terms: D015169:Colony Count, Microbial; D003343:Corrosion; D060766:Drinking Water / Q000737:chemistry*; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D007854:Lead / Q000032:analysis*; D013058:Mass Spectrometry; D010710:Phosphates / Q000737:chemistry; D011330:Prisons; D011792:Quebec; D012044:Regression Analysis; D012498:Sanitary Engineering / Q000295:instrumentation*; D018709:Statistics, Nonparametric; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D015032:Zinc / Q000032:analysis
chemical_list: D060766:Drinking Water; D010710:Phosphates; D014874:Water Pollutants, Chemical; D007854:Lead; D015032:Zinc