Lead Isotopic Fingerprinting: Exploring Applications to Tap Water Lead Contamination in Trenton, NJ

Abstract

Lead ingestion via tap water continues to be a pervasive global issue despite increased awareness of the serious negative health impacts accompanied by even low-level exposure. Corroding lead service lines (LSLs) are believed to be the primary contributor to tap water Pb contamination. Despite the recent increased public focus on service lines, there remain many unknowns, particularly relating to the leaching rates and source contribution to tap water lead concentrations. Additionally, the joint private/public ownership of service lines has lead to poor record keeping resulting in expensive and invasive LSL identification methods. This study presents an isotopic analysis of Pb in LSLs and tap water samples in Trenton, NJ in order to further examine the role of LSLs in drinking water contamination. The methodology is twofold: (1) use Q-ICP-MS to measure reliable and precise Pb isotope fingerprints of LSL and water samples and (2) employ statistical and geospatial data processing techniques to constrain, characterize, and quantify LSLs as a tap water contamination source. This study reveals, through an examination of 208-Pb/206-Pb and 207-Pb/206-Pb concentrations, the presence of multiple contamination sources in residential water systems, preliminary support for the EPA assertion that LSLs are a dominant contamination source, and a preliminary quantification of the contribution of LSLs to tap water Pb contamination. Additionally, a geospatial and high dimension analysis of LSL isotopes reveals potential geospatial clustering of LSL isotope fingerprints, which could have future applications in non-invasive LSL identification.