title: Profile sampling to characterize particulate lead risks in potable water.
abstract: Traditional lead (Pb) profiling, or collecting sequential liters of water that flow from a consumer tap after a stagnation event, has recently received widespread use in understanding sources of Pb in drinking water and risks to consumer health, but has limitations in quantifying particulate Pb risks. A new profiling protocol was developed in which a series of traditional profiles are collected from the same tap at escalating flow rates. The results revealed marked differences in risks of Pb exposure from one consumer home to another as a function of flow rate, with homes grouped into four risk categories with differing flushing requirements and public education to protect consumers. On average, Pb concentrations detected in water at high flow without stagnation were at least three to four times higher than in first draw samples collected at low flow with stagnation, demonstrating a new "worst case" lead release scenario, contrary to the original regulatory assumption that stagnant, first draw samples contain the highest lead concentrations. Testing also revealed that in some cases water samples with visible particulates had much higher Pb than samples without visible particulates, and tests of different sample handling protocols confirmed that some EPA-allowed methods would not quantify as much as 99.9% of the Pb actually present (avg. 27% of Pb not quantified).
authors.affiliation: Virginia Tech , Civil and Environmental Engineering, 418 Durham Hall, Blacksburg, Virginia 24061, United States.
authors.forename: Brandi
authors.initials: B
authors.lastname: Clark
authors.forename: Sheldon
authors.initials: S
authors.lastname: Masters
authors.forename: Marc
authors.initials: M
authors.lastname: Edwards
mesh_terms: D004219:District of Columbia; D060766:Drinking Water / Q000737:chemistry*; D006801:Humans; D007854:Lead / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D011634:Public Health; D012212:Rheology; D012237:Rhode Island; D012307:Risk Factors; D012926:Social Control, Formal; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply
chemical_list: D060766:Drinking Water; D052638:Particulate Matter; D014874:Water Pollutants, Chemical; D007854:Lead